Strong Inversion Research Articles

Petroleum geological characteristics and exploration targets of the oil-rich sags in the Central and West African Rift System

Based on seismic, drilling, and source rock analysis data, the petroleum geological characteristics and future exploration direction of the oil-rich sags in the Central and West African Rift System (CWARS) are discussed. The study shows that the Central African Rift System mainly develops high-quality lacustrine source rocks in the Lower Cretaceous, and the West African Rift System mainly develops high-quality terrigenous organic matter-rich marine source rocks in the Upper Cretaceous, and the two types of source rocks provide a material basis for the enrichment of oil and gas in the CWARS. Multiple sets of reservoir rocks including fractured basement and three sets of regional cap rocks in the Lower Cretaceous, the Upper Cretaceous, and the Paleogene are developed in the CWARS. Since the Late Mesozoic, due to the geodynamic factors including the dextral strike-slip movement of the Central African Shear Zone, the basins in different directions of the CWARS differ in terms of rifting stages, intervals of regional cap rocks, trap types and accumulation models. The NE–SW trending basins have mainly preserved one stage of rifting in the Early Cretaceous, with regional cap rocks developed in the Lower Cretaceous strata, forming traps of reverse anticlines, flower-shaped structures and basement buried hill, and two types of hydrocarbon accumulation models of “source and reservoir in the same formation, and accumulation inside source rocks” and “up-source and down-reservoir, and accumulation below source rocks”. The NW–SE basins are characterized by multiple rifting stages superimposition, with the development of regional cap rocks in the Upper Cretaceous and Paleogene, forming traps of draping anticlines, faulted anticlines, antithetic fault blocks and the accumulation model of “down-source and up-reservoir, and accumulation above source rocks”. The combination of reservoir and cap rocks inside source rocks of basins with multiple superimposed rifting stages, as well as the lithologic reservoirs and the shale oil inside source rocks of strong inversion basins are important fields for future exploration in basins of the CWARS.

Ocular surface lesions in clinical grades of Bell's phenomenon.

Bell's phenomenon, also known as the palpebral oculogyric reflex, is a critical reflex that protects the cornea. We developed an innovative, simple, and practical grading scale for Bell's phenomenon that includes the inverse Bell's phenomenon. Using this scale, we investigated the characteristics of Bell's phenomenon among asymptomatic individuals in different age groups and examined the frequency of ocular surface lesions in asymptomatic and symptomatic participants with different grades. In this cross-sectional study, we randomly included 330 eyes of 165 asymptomatic, healthy, White Turkish individuals who attended the outpatient eye clinic, with a male-to-female ratio of 1:1.4, in the control group. These were categorized into four age groups: 4 - 20 years, 21 - 40 years, 41 - 60 years, and > 60 years. Eighty eyes from 40 patients with ocular surface lesions and absence of grade + 2 Bell's phenomenon were included in the symptomatic group. Bell's phenomenon was classified into five grades: grade + 2 (strong positive), grade + 1 (weak positive), grade 0 (no Bell's phenomenon, no eye movement), grade -1 (weak inverse), and grade -2 (strong inverse). We detected higher frequencies of grade + 2, + 1, and 0 in individuals aged 4 - 40, 41 - 60, and > 60 years, respectively. There was a significant difference between age groups in the frequencies of different grades (P < 0.001). Pairwise analysis revealed a significantly lower frequency of grade + 2 in the age group > 60 years compared with the 4 - 20 and 21 - 40 year groups (both P < 0.05). Grade + 2 was the most frequent in both sexes. We detected grade 0 in 27.1% of men and 22.1% of women in the control group, with no significant difference in the frequencies of different grades between sexes (P > 0.05). We observed significant differences between grades with respect to the frequency of ocular surface lesions (P < 0.001). Pairwise analysis revealed a significantly higher frequency of ocular surface lesions in asymptomatic individuals with grade 0 and all four other grades (all P < 0.001). However, the frequency of ocular surface lesions was comparable between sexes (P > 0.05). Of the 40 symptomatic individuals, 28 (70%), 5 (12.5%), 4 (10%), and 3 (7.5%) had grade 0, + 1, -1, and -2, respectively. The number of symptomatic patients was higher in grade 0 (n = 28) than in other grades (grade + 1, -1, and -2: n = 12 patients), and these individuals had a higher frequency of ocular surface lesions (n = 38 lesions) than others (grade + 1, -1, and -2: 7 lesions). Using a simple, practical grading scale for Bell's phenomenon that includes inverse Bell's phenomenon, we observed that inverse Bell's phenomenon is a reflex that may be present in healthy individuals and could have a protective effect on the eye, although not to such a degree as a strong Bell's phenomenon. Our observations imply that bilateral conjunctival calcifications/Vogt's limbal girdle may be associated with grades 0 and + 1 Bell's phenomenon. Further large-scale studies are needed to determine the frequency of Bell's phenomenon in the general population using this innovative, simple, practical grading scale, and to identify the protective or injurious effect of each grade on the ocular surface.

Planetary Boundary Layer Flow over Complex Terrain during a Cold Surge Event: A Case Study

Planetary boundary layer (PBL) flow over complex terrain during a cold surge event was investigated using 3-hourly radiosonde measurements in upwind, near ridge, and downwind locations of mountains in the northeastern part of Republic of Korea and using a high-resolution (333-m) numerical simulation. A cold surge occurred on 23 January 2018 and lasted for 4 days. We analyzed onset day of the cold surge when air temperature dropped rapidly. Analysis of the radiosonde data shows that the PBL was characterized by an adiabatic layer with strong capping inversion in early morning and evening as well as during daytime in the upwind and near-ridge sites. The PBL flow at the near-ridge site was strongest among three sites except at 0600 local standard time (LST) when the PBL flow in the lee was strongest. We performed high-resolution (333-m) numerical simulations using the Weather Research and Forecasting (WRF) model. The adiabatic PBL in the upwind site at 0600 LST was simulated, although its depth was underestimated. The model reproduced the strong low-level wind at 0600 LST and large wind shear during the daytime in the lee, but it did not capture the exact timing of the large wind shear. The model showed overall good performance in simulating the vertical profile of the virtual potential temperature and wind below 2 km above ground level at the three sites, with a high index of agreement (IOA) except for the wind at 1200 and 1500 LST in the lee. To examine the cause for the different behavior of PBL flow in the lee of mountains between 0600 LST and the daytime, we calculated the Froude number for PBL flow using radiosonde measurements based on reduced gravity shallow water (RGSW) theory. At 0600 LST, the upwind Froude number F0 was close to 1, while during the daytime, it was much lower than 1. The observed lee flow behavior was consistent with the flow regime change of a single layer over an obstacle with changing F0; the flow with a propagating lee jump changes into that with a stationary lee jump with decreasing F0. Numerical simulation shows that the steepening of streamlines of lee-wave field leads to a jump-like structure in the lee of mountains during the daytime.

Achieving Superior Thermoelectric Performance in Ge4Se3Te via Symmetry Manipulation with I–V–VI2 Alloying

AbstractAlthough orthorhombic GeSe is predicted to have an ultrahigh figure of merit, ZT ≈ 2.5, up to now, the highest experimental value is ≈0.2 due to the low carrier concentration (nH ≈ 1018 cm−3). Improving symmetry is an effective approach for enhancing the ZT of GeSe‐based materials. With Te‐alloying, Ge4Se3Te displays the two‐dimensional hexagonal structure and high nH ≈ 1.23 × 1021 cm−3. Interestingly, Ge4Se3Te transformed from the hexagonal into the rhombohedral phase with only ≈2% I–V–VI2‐alloying (I = Li, Na, K, Cu, Ag; V = Sb, Bi; VI = Se, Te). According to the calculated results of Ge0.82Ag0.09Bi0.09Se0.614Te0.386 single‐crystal grown via AgBiTe2‐alloying, it exhibits a higher valley degeneracy than the hexagonal Ge4Se3Te. For instance, AgBiTe2‐alloying induces a strong band convergence and band inversion effect, resulting in a significantly enhanced Seebeck coefficient and power factor with a similar nH from 17 µV K−1 and 0.63 µW cm−1 K−2 for pristine Ge4Se3Te to 124 µV K−1 and 5.97 µW cm−1 K−2 for 12%AgBiTe2‐alloyed sample, respectively. Moreover, the sharply reduced phonon velocity, nano‐domain wall structure, and strong anharmonicity lead to low lattice thermal conductivity. As a result, a record‐high average ZT ≈0.95 over 323–773 K with an excellent ZT ≈ 1.30 is achieved at 723 K.

Comprehensive High-Voltage Parameter Extraction Strategy for BSIM-BULK HV Model

In this work, parameter extraction methodology for the BSIM industry standard high-voltage (HV) device compact model is presented. An extraction procedure covers entire range of operation, including weak inversion to strong inversion region, low and high drain biases, and multiple body biases with temperature effects. The extraction procedure is validated with experimental and numerical simulation data for several configurations of HV devices, including geometric variations.

(Invited) In-Depth Understanding of the Key Contributors to the Total Flicker Noise in Advanced Logic Devices

The aim of this work is to perform an in-depth analysis in order to identify the key contributors to the total flicker noise in advanced MOSFET technologies, e.g. UTBOX, FinFET or Gate-all-around (GAA) nanowire or nanosheet FET devices.In this abstract, as an example, we will focus on p-type gate all around silicon vertical nanowire devices fabricated at imec. The transistors have a fixed gate length (LG) of 50 nm and 1200 nanowires in parallel (N), each nanowire (NW) having a diameter (WNW) of 20 nm. The total width (W) of the device is calculated as . The gate stack corresponds to an equivalent oxide thickness (EOT) of 0.9 nm. A full description of the process flow of the devices is presented in [1]. Comparison between the Y-function strategy of [2] and McLarty methodology [3] permits to estimate with accuracy the DC parameters necessary for low frequency noise modelling, which are summarized in Table 1.Typical low frequency noise spectra are shown in Figure 1. The methodology for the estimation of the low frequency noise parameters is described in [4], but it is obvious that the noise spectra are dominated by 1/f noise and only few Lorentzian contributions appear for some gate voltage polarization. As the corresponding flicker noise levels (K f ), plotted in Figure 2 present a plateau and rise with the increase of the applied gate voltage, the responsible 1/f noise mechanism should be related to the carrier number or correlated carrier number fluctuations mechanism, with a possible contribution of the access resistance 1/f noise.Firstly, the model described in [5-9] expressed as in equation (1) is employed. A linear dependence of the square root of the 1/f noise levels on the measured Id/gm is observed in Figure 3, permitting to estimate from the intercept and slope the flat-band noise level (Svfb) and the W coefficient, respectively. Using the methodology of [9] the estimated W parameter is corrected by the access resistance influence. Good agreement with experimental data in strong inversion may be observed in both cases (Figure 4).Secondly, the model which considers the small signal model of the MOSFET is used, assuming that the channel resistance noise and access resistances noise are uncorrelated noise sources [2,10,11]. The model may be expressed by equation (2) ((13) of [11]), in order to make no assumption concerning the gm/gch ratio. Beyond the threshold voltage, the impact of the cannot be neglected, as observed from Figure 5. It may be observed from Figure 6 that the correlated number fluctuation and mobility noise mechanism cannot explain the flicker noise behavior in very strong inversion, and an additional contribution of the access resistances noise may be considered in order to agree with the experimental data.The noise parameters estimated to agree with the experimental data for both models are summarized in Table 2. It is interesting to note that the experimental data may be explained by both models, but the key contributors are not the same: only correlated number fluctuations and mobility noise mechanism for the first model, and correlated number fluctuations and mobility and access resistance noise mechanisms contribution for the second one. Moreover, the estimated flat-band noise levels are not the same, a much lower Svfb is obtained when the first model is employed. Considering the access resistance impact may correct the W coefficient, but leads to even lower flat-band noise levels, as already reported in [9].These results lead to some questioning about which of these two models is most accurate and give good indications on the key contributors and estimated parameters of the total flicker noise.

What Are the Causes of Super Activity of Solar Active Regions?

Flare productivity varies among solar active regions (ARs). This study analyzed 20 ARs of contrasting sunspot areas and flare productivities to understand the super flare productivity of certain ARs. We used the flare index (FI) as an indicator of flare activity. We examined the pattern of morphological evolution of magnetic features. Further, we derived a set of magnetic feature parameters to quantitatively characterize ARs. Our study found that the correlation coefficient is the highest (r = 0.78) between FI and the length of the strong gradient polarity inversion line (SgPIL), while the coefficient is the lowest (r = 0.14) between FI and the total unsigned magnetic flux. For the selected ARs, this study also found that the super flare productive ARs have SgPILs (R value) longer (greater) than 50 Mm (4.5). These results suggest that flare productivity is mainly controlled by the size of the subregion that comprises close interaction of opposite magnetic polarities and is weakly correlated with the size of the whole ARs. Further, even though magnetic flux emergence is important, this study shows that it alone is insufficient to increase flare productivity. New emergence can drive either the interaction of like or opposite magnetic polarities of nonconjugate pairs (i.e., polarities not from the same bipole). In the former case, the magnetic configuration remains simple, and flare productivity would be low. In the latter case, the convergence of opposite magnetic fluxes of nonconjugate pairs results in a magnetic configuration with long SgPIL and an increase in flare productivity.

Plasma levels of BCMA-positive extracellular vesicles correlate to response and side effects in myeloma patients treated with belantamab-mafodotin.

In myeloma patients, high levels of soluble BCMA (sBCMA) can limit the efficacy of BCMA-directed therapies. Belantamab-mafodotin is a BCMA antibody-drug conjugate and shows good overall response rates in heavily pretreated patients but progression-free survival data are poor. As the drug induces apoptosis, we hypothesized that sBCMA includes extracellular vesicles (EV) and thus evaluated numbers of BCMA-EV before and during belantamab therapy in 10 myeloma patients. BCMA-EV were significantly higher in patients prior to Belantamab (median: 3227/μl; p = .013) than in other myeloma patients before therapy (n = 10; 1082/μl) or healthy volunteers (n = 10; 980/μl). During therapy, BCMA-EV showed a significant increase to a maximum of 8292/μl (p = .028). Maximal changes in BCMA-EV (Δmax = BCMA-EV at C1/maximal BCMA-EV) showed a strong inverse, logarithmic correlation (r = -.950; p < .001) with FLC ratio changes (Δmax = FLC ratio at C1/minimal FLC ratio) and BCMA-EV peaks often preceded FLC progression. Correlating increase of LDH and BCMA-EV levels, together with clinical symptoms, point to a mafodotin-induced eryptosis. In summary, BCMA-EV are a part of sBCMA, peak levels precede progression, and their measurement might be helpful in identifying resistance mechanisms and side effects of BCMA targeted therapies.

Comparative analysis of the dynamics of indicators of timely detection of malignant neoplasms of the stomach in Ukraine and Bukovyna for 2006-2020

Oncological morbidity usually increases with age, and also depends on gender composition and inequalities in access to specialized medical care. Malignant neoplasms of the stomach (MNS), which affect the population of different countries of the world with different frequency, were no exception. Ukraine belongs to the countries with high morbidity and mortality, and the indicators of survival and the specific weight of detection at different stages indicate the usually late detection of this pathology.The aim of the study is to assess the scale of the problematic situation of morbidity and mortality from malignant neoplasms of the stomach in Ukraine as a whole and in Bukovyna in particular.Material and methods. In the process of research, using system-historical and bibliosemantic methods, data from the State Statistics Service of Ukraine (results of the last population census in 2001 and estimated data for the following years 2002-2021) were processed; National Cancer Registry of Ukraine for the past 15 years (2006-2020) and annual "Reports on malignant neoplasms" (form No. 7) for 2016 and 2020.Results. It was established that in Ukraine during 2007-2020 there was a gradual decrease in the specific weight of cases first detected at the I-II stages, and an increase in the frequency of late diagnosis - at the IV stage, which was especially pronounced in the Chernivtsi region. On the other hand, the share of cases of MNS diagnosed at the IV stage, on the contrary, increased in Ukraine from 30.9% in 2007 to 42.7% in 2020 and even more intensively in the Chernivtsi region - from 29.1% to 52.0%. At the same time, the situation with the timely detection of MNSs began to deteriorate both in the country and in the region. Against the background of established low levels of detection of MNSs during preventive examinations and high percentages of late diagnosis, the mortality rate within a year after detection of the pathology was consistently high. The study proved a strong inverse, reliable relationship between the specific weight of preventive examinations and the percentage of diagnosed cases at the neglected IV stage: rxy=-0.90, p&lt;0.05.Conclusion. Over the past fifteen years in Ukraine, and especially in the Chernivtsi region, there has been deterioration in the indicators of early detection of MNSs among the male population.

Momentum-space spin texture induced by strain gradient in nominally centrosymmetric SrIrO3 films

ABSTRACT Spin texture in k-space is a consequence of spin splitting due to strong spin–orbit coupling and inversion symmetry breaking. It underlies fertile spin transport phenomena and is of crucial importance for spintronics. Here, we observe the spin texture in k-space of nominally centrosymmetric SrIrO3 grown on NdGaO3 (110) substrates, using non-linear magnetotransport measurements. We demonstrate that the spin texture is not only induced by the interface, which inherently breaks the inversion symmetry in strong spin–orbit coupled SrIrO3 films, but also originates from the film bulk. Structural analysis reveals that thicker SrIrO3 films exhibit a strain gradient, which could be considered as a continuous change in the lattice constant across different layers and breaks the inversion symmetry throughout the entire SrIrO3 films, giving rise to the spin texture in k-space. First-principles calculations reveal that the strain gradient creates large spin-splitting bands, inducing the spin texture with anisotropy, which is consistent with our experimental observations. Our results offer an efficient method for inducing the spin textures in k-space.

Modelling and design of asynchronous receptive circuit for cone pathways

In this paper, asynchronous receptive circuit of retinal pathway is proposed for cone cells. Cone cells respond differently to different wavelengths of light and they are responsible for color vision. The cells present in retinal pathway namely cone photoreceptor, bipolar cell, amacrine cell and ganglion cell are mimicked using 180 nm Complementary Metal Oxide Semiconductor (CMOS) technology in strong inversion region. The proposed circuit is event based and hence asynchronous in nature. Additionally, amacrine stage is mimicked such that analog multiplexing occurs which is matching with its biological behavior. Both these features give output near to response of actual biological retinal pathway. The circuit detects wavelengths in visible spectrum of light with temporal contrast. At amacrine stage, selectivity is achieved without any external control signal which shows intelligent behavior at analog circuit level. The concept of color sensitivity of cone is considered to generate input stimulus of the circuit using Commission on Illumination (CIE) standard. The power consumed by the entire pathway circuit is 183 mW.

Subseasonal Variation Characteristics of Low-Cloud Fraction in Southeastern and Northwestern North Pacific

The subseasonal variability of the low-cloud fraction (LCF) over the southeastern North Pacific (SENP) and northwestern North Pacific (NWNP) was studied using satellite observations and the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis. It is found that subseasonal variability of the LCF was closely related to variations in the estimated inversion strength (EIS), sea surface wind speed (SSW), sensible heat flux (SHF), sea surface temperature (SST), surface temperature advection (Tadv), relative humidity (RH), surface level pressure (SLP) and surface air temperature (SAT). An increase in the LCF over the SENP is associated with the development of an anomalous anticyclonic circulation, which is located on the west coast of America. The cold advection, together with the subsidence warming associated with the anticyclonic circulation, strengthens the temperature inversion, favoring the development of the LCF. In the NWNP, the maximum LCF anomaly was also correlated with the stable boundary layer. The southerly wind blows airflow over the Kuroshio Extension from the subtropics, which brings warm and moist air. When air flows to the colder sea surface, it is cooled and condensed by the intensified heat exchange. A lead-lag composite analysis indicates that the mechanisms are different between the SENP and the NWNP, possibly due to the different types of low-level clouds over these two regions. In the SENP, the trade cumulus dominates under a strong capping inversion over the subtropics, whereas fog and stratus often occur under a shallow capping inversion in the NWNP. The effects of atmospheric circulation are also discussed.

Remote Sensing of Planetary Boundary Layer Thermodynamic and Material Structures over a Large Steel Plant, China

Air pollutants emitted by industries can significantly affect local air quality and jeopardize human health, and the study of the boundary layer thermodynamic structure and diffusion capacity over industrial plants can be beneficial for the improvement of corporate air pollution control measures. The continuous high temporal and spatial resolution monitoring of the boundary layer structure (thermal, dynamic, and material) by advanced remote sensing instruments over a single strong industrial source (steel plant) in Shanxi Province, China, from May to June 2021 revealed the boundary layer characteristics under the influence of a single strong local anthropogenic influence. Strong nocturnal temperature inversions and grounded temperature inversions were prone to occur over industrial sources. The local wind field was characterized by significant daily variations, with the whole-layer airflow during the daytime dominated by southwesterly winds. At night, under the influence of radiation, topography, and surface, the airflow was dominated by easterly winds with low speeds (less than 2 m/s) in the low altitude range of 100 m, while the wind direction was still dominated by southwesterly winds with higher speeds in the altitude of 100 m. In addition, the average atmospheric diffusion capacity increased significantly with height in the 500 m altitude range, with an increase in rate of about 2~3 times/50 m, and continued to show a discontinuous increasing trend above 500 m. Combined with the wind direction and wind speed contours, it can be seen that the pollutants can be effectively dispersed at a height of 100 m. The thermal and turbulent boundary layer heights were highly consistent, and the material boundary layer height was significantly higher than the thermal and turbulent boundary layer heights during the daytime when convection was strong.

Nighttime ozone in the lower boundary layer: insights from 3-year tower-based measurements in South China and regional air quality modeling

Abstract. Nighttime ozone in the lower boundary layer regulates atmospheric chemistry and surface ozone air quality, but our understanding of its vertical structure and impact is largely limited by the extreme sparsity of direct measurements. Here we present 3-year (2017–2019) measurements of ozone in the lower boundary layer (up to 500 m) from the Canton Tower in Guangzhou, the core megacity in South China, and interpret the measurements with a 1-month high-resolution chemical simulation from the Community Multiscale Air Quality (CMAQ) model. Measurements are available at 10, 118, 168, and 488 m, with the highest (488 m) measurement platform higher than the typical height of the nighttime stable boundary layer that allows direct measurements of ozone in the nighttime residual layer (RL). We find that ozone increases with altitude in the lower boundary layer throughout the day, with a vertical ozone gradient between the 10 and 488 m heights (ΔO3/ΔH10–488 m) of 3.6–6.4 ppbv hm−1 in nighttime and 4.4–5.8 ppbv hm−1 in daytime. We identify a high ozone residual ratio, defined as the ratio of ozone concentration averaged over nighttime to that in the afternoon (14:00–17:00 LT), of 69 %–90 % in January, April, and October, remarkably higher than that in the other three layers (29 %–51 %). Ozone in the afternoon convective mixing layer provides the source of ozone in the RL, and strong temperature inversion facilitates the ability of RL to store ozone from the daytime convective mixing layer. The tower-based measurement also indicates that the nighttime surface Ox (Ox= O3+NO2) level can be an effective indicator of RL ozone if direct measurement is not available. We further find significant influences of nocturnal RL ozone on both the nighttime and the following day's daytime surface ozone air quality. During the surface nighttime ozone enhancement (NOE) event, we observe a significant decrease in ozone and an increase in NO2 and CO at the 488 m height, in contrast to their changes at the surface, a typical feature of enhanced vertical mixing. The enhanced vertical mixing leads to an NOE event by introducing ozone-rich and NOx-poor air into the RL to enter the nighttime stable boundary layer. The CMAQ model simulations also demonstrate an enhanced positive contribution of vertical diffusion (ΔVDIF) to ozone at the 10 and 118 m heights and a negative contribution at the 168 and 488 m heights during the NOE event. We also observe a strong correlation between nighttime RL ozone and the following day's surface maximum daily 8 h average (MDA8) ozone. This is tied to enhanced vertical mixing with the collapse of nighttime RL and the development of a convective mixing layer, which is supported by the CMAQ diagnosis of the ozone budget, suggesting that the mixing of ozone-rich air from nighttime RL downward to the surface via the entrainment is an important mechanism for aggravating ozone pollution the following day. We find that the bias in CMAQ-simulated surface MDA8 ozone the following day shows a strong correlation coefficient (r= 0.74) with the bias in nighttime ozone in the RL, highlighting the necessity to correct air quality model bias in the nighttime RL ozone for accurate prediction of daytime ozone. Our study thus highlights the value of long-term tower-based measurements for understanding the coupling between nighttime ozone in the RL, surface ozone air quality, and boundary layer dynamics.

A Surface Potential Model for Metal-Oxide-Semiconductor Transistors Operating near the Threshold Voltage

Device physics and accurate transistor modeling are necessary to reduce the operating voltage near the threshold for power-constrained circuits. Conventional device modeling for metal-oxide-semiconductor (MOS) transistors focuses on operations in either strong or weak inversion regimes, and the electrostatics at gate biases near the threshold voltage is rarely studied. This research proposed an analytical model to describe the distribution of the surface potential along the channel for near-threshold operation. Numerical device simulations were also performed to investigate the electrostatics near the threshold voltage. The numerical simulation with constant carrier mobility showed an overshoot in the transconductance due to decay of the lateral electric field with gate bias. The decay of the lateral electric field was predicted by the proposed analytical surface potential model which considered widening the channel length with flooding of the inversion carriers in the channel and gate overlap regions. The channel length widening effect saturated as the gate bias further increased. Therefore, evident transconductance overshoot was observed near the threshold voltage in short-channel devices.

The covariability between temperature inversions and aerosol vertical distribution over China

Temperature inversions (TI) have a unique impact on the regulation of aerosol distribution. However, it remains unclear the covariability of TI and aerosol vertical distribution. To address this issue, ten years CALIPSO observations and the fifth-generation European Centre for Medium-Range Weather Forecasts atmospheric reanalysis system (ERA5) data from January 2008 to December 2017 across China were collected. The aim was to explore the relationship between TI and the aerosol vertical distribution. The characteristics of TI and aerosol vertical distribution have been analysed in the Taklimakan Desert (TD), North China (NC), South China (SC) and Sichuan Basin (SB). The results demonstrate that the frequency of TI, inversion strength (ΔT), and TI height (TIH) follow a similar seasonal pattern across the four areas. Specifically, they are highest in winter, followed by spring and autumn, and the least in summer. Notably, NC exhibits a significantly higher average frequency (10.3%) of TI during summertime compared to the other regions. This may be a result of the heating effect of the elevated black carbon aerosol on the upper atmosphere. Moreover, the observations demonstrate that aerosol optical depth (AOD) above the TIH in the four areas is greater during spring and summer months compared to autumn and winter. It indicates that there is an obvious aerosol high-level transport over the Chinese mainland in spring and summer. In winter months, most of the aerosols are located below the TIH. This phenomenon occurs due to the influence of a strong inversion layer and adverse atmospheric ventilation conditions. In addition, the average AOD below TIH increases with the ΔT increased in TD region, supporting the hypothesis that a strong inversion can suppress surface aerosols below the TI. Conversely, in NC and SC regions, the average AOD below (above) TIH decreases (increases) as the ΔT increases. It indicates that the strong atmospheric stability forms a more effective transmission channel, resulting in the accumulation of aerosols above TIH. These findings have important support for studying aerosol transport.

Refining grain structure and improving elongation properties in AZ31 magnesium alloy sheets using hard plate accumulative roll bonding

Magnesium alloy sheet are an ideal choice for achieving material and structural light weighting. Traditional ARB technology can significantly reduce the size of magnesium alloy sheet, but it is faced with the challenge of strong plastic inversion. In addition, it is easy to produce edge cracking defects, and it is also difficult to control the quality of the sheet. In this study, we prepared AZ31 magnesium alloy sheet by HP-ARB process for the first time. The results show that compared to ARB, the HP-ARB sheet has remarkable improvements in and mechanical properties.After two passes, the average grain size of HP-ARB decreased from 6.19 μm to 4.58 μm, tensile strength reaches 291 MPa, and the elongation is 10.1%, which significantly increased to 55.4% compared with ARB. HP-ARB has the ability to transform part of shear stress into compressive stress, which improves the stress distribution on the sheet. On one hand, a large amount of energy stored in dislocations provides energy for DRX, which makes the process more complete, leading to microstructure refinement and grain orientation randomization. This leads to the deviation of texture orientation to TD direction, which leads to the decrease of pole density and weakening of the strong basal texture. On the other hand, dislocation density (ρD) of the sheet is relatively low. The average Schmidt factor of prismatic <a> slip and pyramidal <c+a> slip in the HP-ARB process is higher, which is beneficial to dislocation slip, thus promoting an increase of sheet elongation. This provides a new strategy for the forming and manufacture of high performance magnesium alloy sheet.

A low-voltage MOS translinear loop, biased using FVF and its applications in realizing square-rooter and squarer circuits

In this paper, a new MOS Translinear Loop (MTL), biased using Flipped-Voltage-Follower, has been presented and its use in the CMOS Current-Mode (CM) realization of the non-linear functional circuits namely, square-rooting and squaring has been demonstrated. The new MTL facilitates the low-voltage operation of the proposed CMOS CM circuits while maintaining all the MOSFETs operating in strong inversion mode. The workability of both the proposed circuits has been validated by simulations carried out on Cadence Virtuoso software using 0.18 μm CMOS technology at a DC power supply voltage of 0.85 V and the results of the same have been presented. Furthermore, temperature and corner analyses have been performed to verify the robustness of the proposed circuits in the practical environment.

Tectonic evolution of the Red river basin and adjacent area (Vietnam) in Cenozoic era

Basing on the structural and tectonophysic analysis of data collected from outcrops around Tonkin Gulf and the results of analysis of seismic setions of the Red river basin, the fourmain successivetectonic phases with specific paleostress fields since beginning of Cenozoic era have been established. The first middle Eocene-early Miocene (45-15.97 my) tectonic phase, with sub-latitudinal compression and sub-longitudinal extension, was accompanied by large scale sinistral displacement of the Red river fault, the extension centers of the Red river basin andseafloor spreading of East Vietnam Sea. The second middle-late of middle Miocene (13, 82-7, 25 my) tectonic phase, with sub-longitudinal compression and sub-latitudinal extension, has created a local depocenter N-S orientation; right-lateral strike slip of the Red river fault and first inversion of the basin. The third late Miocene (~7.25-5.33 my BP) tectonic phase, with NE-SWcompression, has caused strongest inversion in the Red river basin with strong uplift of some blocks and significant shrinkage of the RRB up to 15–20%. The fourth Quaternary-to-Recent tectonic phase, with NW-SE compression and NE-SW extension, is appeared in form of existing of the recent grabens of NW-SE direction, earthquakes and GPS data. Formation and development of the Red river basin was controlled by the tectonic activities and closely connected to NW-SE trending fault system of regional scale such as the Red river fault, Chay river fault, Lo river faults as well the local faults such as Ca river fault, Rao Nay river fault, Thakhek-Da Nang fault. Some spectacular examples for tectonic activity can be seen in form of geographic features of Vietnam, Laos and Thailand, in particular the mountain ranges, such as Truong Son (or Viet-Laos) belt. The Red river fault when comes to the sea becomes less active, while the other faults of the RRFS like Chay river and Lo river had played the main role in development of the Red river basin.

The correlation between body weight, serotonin levels, mental health status, sleep disorders and metabolism in patients with obesity

Background. The significant spread of obesity stimulates researchers to search for etiopathogenic treatment by studying the relationships and dependencies of the hormonal, neurochemical and psychosomatic components. The purpose of the study is to determine the correlation between body weight, serotonin level, mental health status, sleep disorders and metabolism in obese patients. Materials and methods. In a cohort, prospective study, 75 patients with obesity were observed for 6 months. They were divided into 2 groups depending on the detected psychosocial characteristics and sleep disorders with the appropriate treatment using a patient-oriented approach. The examination included studying body mass index (BMI), abdominal obesity indices (body surface area, waist/hip ratio, conicity index, a body shape index, abdominal volume index), blood pressure, lipid profile, fasting glucose, insulin, leptin, serotonin, assessment of psychosocial status and sleep quality with Hospital Anxiety and Depression Scale (HADS), Beck’s Depression Inventory (BDI), Hamilton Anxiety Rating Scale (HAM-A), Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), quality of life using the SF-36 questionnaire. Statistical analysis was performed using IBM SPSS Statistics, Statistica 12, Excel 2010. Results. At baseline, the patients had obesity class I and II. Тhe calculated indices of abdominal obesity, indicators of lipid and carbohydrate metabolism, scores of questionnaires of eating behavior, anxiety and depression, quality of sleep, sleepiness and leptin level exceeded the recommended values, while the level of serotonin, the scores of the SF-36 had low values that significantly improved in dynamics. Strong direct correlations at baseline were found between BMI, abdominal obesity indices, blood pressure, indicators of lipid and carbohydrate metabolism, leptin, HADS, BDI, HAM-A, ESS, PSQI global score; a strong inverse (negative) relationship was noted between BMI and the levels of high-density lipoprotein and serotonin. A high negative correlation was found between serotonin and BMI, abdominal obesity indices (body surface area, a body shape index, abdominal volume index, conicity index), blood pressure, indicators of lipid and carbohydrate metabolism, HADS, HAM-A, BDI, PSQI global score, sleep quality, latency, duration, efficiency and the ESS. Conclusions. The high BMI correlates with a low level of serotonin, increased level of anxiety and depression, drowsiness, deterioration of the quality of sleep and life, disorders of lipid and carbohydrate metabolism, which are mutually aggravating factors for the development of obesity and other non-infectious diseases; it must be taken into account when determining approaches to comprehensive patient-oriented treatment of obesity.