Effective Channel Research Articles

Steering charge flow in hierarchical ZnIn2S4/TiO2/Ti3C2 heterojunction for noble-metal-free photocatalytic hydrogen production

The construction of effective photogenerated charge transfer channels through interface engineering is the key to achieving the highly efficient of photocatalysts. Herein, sandwich-like ZnIn2S4/TiO2/Ti3C2 nanosheets integrated type-II heterostructure with Schottky junction are reasonably fabricated by low temperature in-situ growth method. Benefitting from the intensive visible light absorption of ZnIn2S4, the fast electron transport of TiO2, the rich active sites in Ti3C2, as well as the intimate interface coupling and the matched band alignment among ternary components, enhanced hydrogen production can be achieved with ZnIn2S4/TiO2/Ti3C2 hierarchical photocatalyst under visible light irradiation in the absence of noble metal co-catalysts. The concept of coupling type-II heterostructure with the Schottky barrier can steer the charge flow and boost the charge carrier separation and transfer across the interfacial domain, which may spark new ensemble design for efficient solar energy harvesting and conversion.

Design insights into a junctionless nanosheet FET (JL-NSFET) for switching and Analog/RF applications: Device to circuit level assessment

- The advent in semiconductor technology paved the way for electronic industry to place in front row. The nanosheet (NS) device is a type gate all around (GAA) architecture provides an excellent gate electrostatic to suppress the short channel effects (SCEs) and scale it further below sub-7nm technology node. This paper provides a complete design insight from device to circuit of a two sheet NSFET with geometrical variations. All digital and analog/RF parameters are extracted and analyzed based on gate length (LG), sheet thickness (TNS), sheet width (WNS), and spacer material variations. As LG is varied from 8 nm to 12 nm, ION/IOFF is enhanced from 0.249 × 108 to 2.86 × 108 due to improved gate control over the channel region which is also reflected in DIBL to 40.82 % whereas, at lower LG analog/RF metrics are better. The TNS play a vital role in device characteristics, as TNS decreases the chance of interaction of electric field from source to drain decreases owing to full volume conduction and thereby ameliorated performance of JL NSFET. As TNS is varied from 7 nm to 5 nm, all electrical characteristics are improved and analog/RF parameters gm, Av, fT, TFP and GTFP are improved to 10.3 %, 18.4 %, 12.1 % 18.5 % and 54.04 %, respectively. Increase in WNS from 10 nm to 20 nm results into increased effective width of a device, it leads to higher ION current which further impacts on electrical and analog/RF parameters. The DIBL, gm, fT, GFP, TFP and GTFP are enhanced to 63.7 %, 37.9 %, 34.9 %, 9.7 %, 33.5 %, 9.1 %, respectively. The spacer materials are varying from Al2O3 (k = 18), HfO2 (k = 22), ZrO2 (k = 25) to TiO2 (k = 44), the electrical characteristics are better at higher-k whereas analog/RF performances are superior at lower-k. Further, digital circuit elements NOT, NAND and NOR gates are designed, simulated and the delays are examined as 4.25ps, 6.45ps and 5.12ps, respectively. The NML and NMH of NOT gate are noticed as 295 mV and 280 mV at 0.7 V of supply voltage. Furthermore, a common source (CS) amplifier is also simulated and gain of 3.3 is noticed. The aforementioned analysis revels the JL NSFET is best suitable candidate for future nanoscale applications.

Research on building extraction from remote sensing imagery using efficient lightweight residual network

Automatic building extraction from very high-resolution remote sensing images is of great significance in several application domains, such as emergency information analysis and intelligent city construction. In recent years, with the development of deep learning technology, convolutional neural networks (CNNs) have made considerable progress in improving the accuracy of building extraction from remote sensing imagery. However, most existing methods require numerous parameters and large amounts of computing and storage resources. This affects their efficiency and limits their practical application. In this study, to balance the accuracy and amount of computation required for building extraction, a novel efficient lightweight residual network (ELRNet) with an encoder-decoder structure is proposed for building extraction. ELRNet consists of a series of downsampling blocks and lightweight feature extraction modules (LFEMs) for the encoder and an appropriate combination of LFEMs and upsampling blocks for the decoder. The key to the proposed ELRNet is the LFEM which has depthwise-factorised convolution incorporated in its design. In addition, the effective channel attention (ECA) added to LFEM, performs local cross-channel interactions, thereby fully extracting the relevant information between channels. The performance of ELRNet was evaluated on the public WHU Building dataset, achieving 88.24% IoU with 2.92 GFLOPs and 0.23 million parameters. The proposed ELRNet was compared with six state-of-the-art baseline networks (SegNet, U-Net, ENet, EDANet, ESFNet, and ERFNet). The results show that ELRNet offers a better tradeoff between accuracy and efficiency in the automatic extraction of buildings in very highresolution remote sensing images. This code is publicly available on GitHub (https://github.com/GaoAi/ELRNet).

Frequency splitting in undulator radiation from solid-state crystalline undulator

The set of frequencies and angular properties of radiation emitted from a solid-state crystalline undulator based on the channeling effect are considered. High-frequency and low-frequency branches of the undulator radiation and the angular distribution of the emitted radiation are analyzed. The ranges of frequencies and angles of radiation emitted from the solid-state crystalline undulator based on the channeling effect are found. The frequency splitting and the energy threshold in the production of undulator radiation are shown and discussed.

Synergistic catalysis effect of micro-mesoscopic channel for enhanced methyl oleate catalytic cracking to BTX: A molecular simulation study

The hierarchical ZSM-5 zeolite exhibits superior catalytic performance for methyl oleate catalytic cracking to BTX, while the promotion mechanism at the molecular level is still unclear. Herein, the adsorption and diffusion behaviors of reaction species in hierarchical ZSM-5 zeolite, including methyl oleate, C3H6, C4H8 and BTX, were theoretically investigated by Monte Carlo combined with Molecular Dynamics simulation. It is found that the introduction of mesopores exposes the strong adsorption sites (Brønsted acid) without a confinement effect, thereby promoting the adsorption and cracking of methyl oleate. Moreover, the as-formed C3H6 and C4H8 rapidly transfer from mesopore into micropore, enhancing the aromatization reaction to form BTX. Finally, thanks to the adjacent mesopore providing sufficient space for molecule rotation, the desired BTX products easily desorbs from the micropore. Such synergistic catalysis effect of micro-mesoscopic channel increases the BTX yield by decreasing the diffusion coefficient of C3H6 and C4H8 from 13.2 × 10-9 m2/s on the traditional to 6.4 × 10-9 m2/s on the hierarchical ZSM-5. We anticipate that this work could enrich our understanding of the microcosmic mechanism of hierarchical zeolites for prolific aromatics.

High-throughput enrichment of portal venous circulating tumor cells for highly sensitive diagnosis of CA19-9-negative pancreatic cancer patients using inertial microfluidics

The carbohydrate antigen 19-9 (CA19-9) is commonly used as a representative biomarker for pancreatic cancer (PC); however, it lacks sensitivity and specificity for early-stage PC diagnosis. Furthermore, some patients with PC are negative for CA19-9 (<37 U/mL), which introduces additional limitations to their accurate diagnosis and treatment. Hence, improved methods to accurately detect PC stages in CA19-9-negative patients are warranted. In this study, tumor-proximal liquid biopsy and inertial microfluidics were coupled to enable high-throughput enrichment of portal venous circulating tumor cells (CTCs) and support the effective diagnosis of patients with early-stage PC. The proposed inertial microfluidic system was shown to provide size-based enrichment of CTCs using inertial focusing and Dean flow effects in slanted spiral channels. Notably, portal venous blood samples were found to have twice the yield of CTCs (21.4 cells per 5 mL) compared with peripheral blood (10.9 CTCs per 5 mL). A combination of peripheral and portal CTC data along with CA19-9 results showed to greatly improve the average accuracy of CA19-9-negative PC patients from 47.1% with regular CA19-9 tests up to 87.1%. Hence, portal venous CTC-based microfluidic biopsy can be used with high sensitivity and specificity for the diagnosis of early-stage PC, particularly in CA19-9-negative patients.

Pilot scale fabrication of low fouling seawater desalination thin film composite reverse osmosis membrane

We report the pilot scale fabrication of thin film composite seawater reverse osmosis membrane (TFC-SW-RO) with low fouling propensity and improved permeate flux. In situ incorporation of poly(ethylene glycol) (PEG) into the polyamide (PA) network simultaneously improves the permeate flux (effect of hydrophilic channels) and antifouling property of the membrane. The PEG chains exhibit good stability during desalination of SW (NaCl = 33,000 mg L−1, applied pressure = 55.2 bar). The mechanism of PEG stabilization into the PA layer has been elucidated on the basis of hydrogen bond formation between ether linkage of PEG and carboxylic acid group of the PA network as well as steric hindrance posed by the network. The TFC-SW-RO membrane (no PEG) in several 100 m2 batches show pure water permeance of 1.4 L m−2 h−1 bar−1 and 98.5–98.8 % NaCl rejection during SW desalination. On the other hand, TFC-SW-RO-PEG shows pure water permeance of 2.2 L m−2 h−1 bar−1 with marginal drop in NaCl rejection (98.4–98.6 %). The TFC-SW-RO-PEG membrane exhibits improved antifouling (flux recovery ratio = 87 %) property during desalination of SW as compared to that of the pristine membrane (flux recovery ratio = 67 %). This work provides an important strategy for the fabrication of SW TFC RO membrane with improved performance.

The Impact of Spectral and Temporal Degradation on Vocoded Speech Recognition in Early-Blind Individuals.

This study compared the impact of spectral and temporal degradation on vocoded speech recognition between early-blind and sighted subjects. The participants included 25 early-blind subjects (30.32 ± 4.88 years; male:female, 14:11) and 25 age- and sex-matched sighted subjects. Tests included monosyllable recognition in noise at various signal-to-noise ratios (-18 to -4 dB), matrix sentence-in-noise recognition, and vocoded speech recognition with different numbers of channels (4, 8, 16, and 32) and temporal envelope cutoff frequencies (50 vs 500 Hz). Cortical-evoked potentials (N2 and P3b) were measured in response to spectrally and temporally degraded stimuli. The early-blind subjects displayed superior monosyllable and sentence recognition than sighted subjects (all p < 0.01). In the vocoded speech recognition test, a three-way repeated-measure analysis of variance (two groups × four channels × two cutoff frequencies) revealed significant main effects of group, channel, and cutoff frequency (all p < 0.001). Early-blind subjects showed increased sensitivity to spectral degradation for speech recognition, evident in the significant interaction between group and channel (p = 0.007). N2 responses in early-blind subjects exhibited shorter latency and greater amplitude in the 8-channel (p = 0.022 and 0.034, respectively) and shorter latency in the 16-channel (p = 0.049) compared with sighted subjects. In conclusion, early-blind subjects demonstrated speech recognition advantages over sighted subjects, even in the presence of spectral and temporal degradation. Spectral degradation had a greater impact on speech recognition in early-blind subjects, while the effect of temporal degradation was similar in both groups.

Optimization Design of Rocket Deflector Channel Surface Based on Kriging Surrogate Model

This study aims to optimize the gas flow environment of a rocket’s deflector channel. Numerical calculations and analysis were conducted on the influencing factors of a certain type of single-sided deflector channel, with the injection coefficient used as the evaluation index for the flow clearance. The study identified the deflector channel’s impact angle, curvature diameter of the bending section, and distance from the top of the deflector surface to the bottom as important structural parameters. There exists a complex nonlinear relationship between these parameters and the gas flow guiding effect of the deflector channel. The kriging surrogate model was employed for the optimization of the deflector channel’s surface. The results showed that, while meeting the basic requirements of the deflector channel, the optimized design improved the gas flow guiding effect by 27.58%, significantly enhancing the gas flow environment. The optimization error was within 1%, confirming the effectiveness and accuracy of the optimization. This study provides a reference for the future design and optimization of gas flow deflector channels, with the potential to improve the performance and efficiency of rocket deflector channels.

Labor Mobility Networks and Green Total Factor Productivity

Population migration continues to reshape the spatial pattern of China’s population and regional economic development. During this internal migration process, production and consumption patterns often change, ultimately leading to changes in green total factor productivity. This paper, based on the Chinese population census data and 1% sampling survey data from 2005 to 2015, utilizes social network analysis methods to measure the labor mobility network indicators of 284 prefecture-level cities. Further, this paper analyzes the impact and mechanisms of regional network status on green total factor productivity using a panel fixed effects model. We find that as network density increases, the interpersonal connections between regions become closer, and the network exhibits a clear pattern of “concentrated inflows” and “dispersed outflows”, with the trend of forming strong alliances becoming increasingly apparent. Regions positioned centrally either in terms of network in-degree or out-degree exhibit higher green total factor productivity. Among these, the labor mobility network plays a crucial role in enhancing green total factor productivity through the channel of technology diffusion effects, which improve investment efficiency via knowledge exchange and material capital accumulation. The promotive effect of labor network status on green total factor productivity is more pronounced in the eastern regions, where talent quality is higher, and in areas with fewer restrictions from the household registration system.

Impact of Hardware Impairment on the Joint Reconfigurable Intelligent Surface and Robust Transceiver Design in MU-MIMO System

Reconfigurable intelligent surface (RIS) is a revolutionary passive radio technique to facilitate capacity enhancement beyond the current massive multiple-input multiple-output (MIMO) transmission. However, the potential hardware impairment (HWI) of the RIS usually causes inevitable performance degradation and the amplification of imperfect CSI. These impacts still lack full investigation in the RIS-assisted wireless network. This paper developed a robust joint RIS and transceiver design algorithm to minimize the worst-case mean square error (MSE) of the received signal under the HWI effect and imperfect channel state information (CSI) in the RIS-assisted multi-user MIMO (MU-MIMO) wireless network. Specifically, since the proposed robust joint RIS and transceiver design problem yields non-convex characteristics under severe HWI, an iterative three-step convex algorithm is developed to approach the optimality by relaxation and convex transformation. Compared with the state-of-the-art baselines that ignore the HWI, the proposed robust algorithm inhibits the destruction of HWI while raising the worst-case MSE effectively in several numerical simulations. Moreover, due to the properties of the HWI, the performance loss is notable under the magnification of the number of reflected elements in the RIS-assisted MU-MIMO wireless network.

Electroosmotic flow in graphene nanochannels considering steric effects

Graphene nanochannels are excellent channels for electroosmotic flow (EOF) due to their larger slip length. In this study, the fully developed EOF in graphene nanochannels is investigated numerically, where the influence of surface charge mobility on the Navier-slip boundary conditions and the influence of steric effect on the electric potential distribution are considered. In addition, an analytical solution is provided for the scenario with low zeta potential. Detailed investigations are conducted on the impact of slip length, surface charge density, surface charge mobility, effective ion size, solution concentration, and channel height on velocity profiles. The findings indicate that the velocity increases with slip length, surface charge density, and effective ion size. Yet, accounting for surface charge mobility (αs = 0.815) leads to a reduction in slip velocity. It is noteworthy that our investigation focuses on quantifying the velocity decline due to surface charge mobility, as well as the velocity enhancement resulting from the steric effect. By adjusting parameters, such as channel height, bare slip length, and solution concentration, we achieve a maximum velocity increase of approximately 48%. These insights are valuable for optimizing the design of efficient electro-osmotic pumping systems.

A Morphological Assessment On The Effects Of Embankments On Sediment Transport In Sandy Estuaries

Many large estuaries around the world are engineered to some degree for both flood protection of coastal communities and maintenance of economically vital shipping routes. Engineering challenges arise due to the highly dynamic morphological nature of estuaries, where the complex processes of sediment transport are driven by an interplay between the turbulent flows of rivers and tides. Naturally, the planforms of sandy estuaries have the tendency to converge landwards exponentially, where deviations from this shape provide alternating space and constrictions where tidal sandbars and channels form (Leuven et al., 2018-a; 2018-b). In the case of embankment by bank protection and dikes, such topographically forced channels can develop deep scour holes that endanger bank stability. Our objective is to study effects of channel and planform dynamics on scour depth variation near protected banks. To this end, we conducted scale experiments of estuaries with completely fixed banks in the tilting tidal flume the Metronome (Kleinhans et al., 2017). We study the effects of these fixed banks on the morphological behaviour of the channel pattern through one experiment, two repeat experiments, and a control without fixed banks. By collection of much longer timeseries than available in nature, we use the experiments to shed light on the topographic forcing and channel dynamics of these systems, and on the repeatability of Metronome experiments.

A novel configuration capable of enhancing flame acceleration and detonation

This study proposes a novel design concept that leverages the geometric effects of channels with varying diameters and bends to boost flame acceleration and detonation in microchannels. A quasi-direct numerical simulation with detailed chemical kinetics is used to evaluate the processes of flame acceleration and detonation. A comparative study on the impact of equidistant spiral and converging spiral shapes of detonation channels on flame acceleration is conducted and discussed. The results indicate that in the low-speed and high-speed stages of flame propagation, Fermat's spiral channel exhibits a more significant promoting effect on flame acceleration compared to the Archimedes spiral channel. Fermat's spiral channel has significant advantages in terms of combustion efficiency and can save about 30% of fuel during the detonation process. This study helps to further reduce the scale of the detonation system.

Role of electromagnetic interactions in the X(3872) and its analogs

We investigate the role of the electromagnetic interaction in the formation and decay of the X(3872). The binding properties of the X(3872) are studied by assuming the molecular nature and considering the S−D wave mixing, isospin breaking, and coupled channel effects, and in particular the correction from the electromagnetic interaction. The radiative decays can better reflect the difference between the charged and neutral DD¯* components, since the electromagnetic interaction explicitly breaks the isospin symmetry. We further study the radiative decay widths with the obtained wave functions for different DD¯* channels. We also explore other similar hidden-charm molecular states. The electromagnetic interaction can make the molecule tighter. Our result of the radiative decay width for X(3872)→γJ/ψ is in agreement with the experiment. The branching ratio Rγψ is less than 1 in our framework, which supports the Belle and BESIII measurements. Published by the American Physical Society 2024

Atomistic analysis on implantation effects of hydrogen ions and copper ions into 4H-SiC

The microstructure evolution of 4H-SiC under the implantation of hydron ions and copper ions was investigated using molecular dynamics (MD) simulations and experimental analysis. MD models were developed to simulate the implantation of single Cu2+ and H+ ions into SiC, analyzing lattice damage, amorphous defects, and temperature distribution. H+ ion implantation resulted in a higher number of amorphous atoms compared to Cu2+ ions. The maximum atomic temperature during Cu2+ ion implantation was significantly higher (1635 K) than during H+ ion implantation (950 K), although the volume of the temperature rise region was larger in the H+ model. Cu2+ ions induced more severe lattice vibrations than H+ ions. Atom movement along regions of weak lattice binding energy was observed. The study also examined overlapping multiple ion implantations, considering ion type, initial energy, and incident angle. Cu2+ ions exhibited smaller sputtering yield, projection range, number of amorphous atoms, and energy increment compared to H+ ions. A 0° incident angle resulted in higher sputtering yield and increased amorphous structure formation due to the channeling effect, which was more pronounced in the H+ model. The experimental results demonstrate that compared to Cu2+ ions, H+ ions have a greater impact on the surface peak roughness, sub-surface damage depth, and surface damage of SiC samples. It can provide a reliable guidance for selecting process parameters and the types of ions to implant.

Does the transition to low-carbon energy alleviate urban-rural energy inequality? The case of China

This paper aims to investigate whether China can reduce urban-rural energy inequality during its transition to low-carbon energy. Using data from 30 Chinese provinces between 2006 and 2019, we employ the system generalized method of moments (SYS-GMM) to investigate the correlation between low-carbon energy transition (LET) and urban-rural energy inequality. Furthermore, to investigate the mechanism, this study also considers energy service accessibility and industrial structure upgrading. The results of the study show that the degree of LET in China is increasing but with uneven spatial distribution. Moreover, LET is effective in reducing urban-rural energy inequality in China. Specifically, 1 % increase in LET corresponds to 0.045 % reduction in the urban-rural energy inequality index. Additionally, energy service accessibility and industrial structure upgrading are identified as effective channels for LET to mitigate urban-rural energy inequality. Furthermore, our study demonstrates that the alleviating impact of LET on energy inequality is more significant in regions where LET and urban-rural energy inequality levels are high. Drawing on our research results, we suggest policy recommendations to encourage the adoption of low-carbon energy sources and diminish urban-rural energy inequality.

Emotion recognition with reduced channels using CWT based EEG feature representation and a CNN classifier

Objective. Although emotion recognition has been studied for decades, a more accurate classification method that requires less computing is still needed. At present, in many studies, EEG features are extracted from all channels to recognize emotional states, however, there is a lack of an efficient feature domain that improves classification performance and reduces the number of EEG channels. Approach. In this study, a continuous wavelet transform (CWT)-based feature representation of multi-channel EEG data is proposed for automatic emotion recognition. In the proposed feature, the time-frequency domain information is preserved by using CWT coefficients. For a particular EEG channel, each CWT coefficient is mapped into a strength-to-entropy component ratio to obtain a 2D representation. Finally, a 2D feature matrix, namely CEF2D, is created by concatenating these representations from different channels and fed into a deep convolutional neural network architecture. Based on the CWT domain energy-to-entropy ratio, effective channel and CWT scale selection schemes are also proposed to reduce computational complexity. Main results. Compared with previous studies, the results of this study show that valence and arousal classification accuracy has improved in both 3-class and 2-class cases. For the 2-class problem, the average accuracies obtained for valence and arousal dimensions are 98.83% and 98.95%, respectively, and for the 3-class, the accuracies are 98.25% and 98.68%, respectively. Significance. Our findings show that the entropy-based feature of EEG data in the CWT domain is effective for emotion recognition. Utilizing the proposed feature domain, an effective channel selection method can reduce computational complexity.

The Effect of High-Speed Train Channel on the Performance of DVB-Terrestrial Communication Systems

The Effect of High-Speed Train Channel on the Performance of DVB-Terrestrial Communication Systems

Examination of Dominant Factors Affecting The Decision To Purchase Personal Medical Devices

This study aims to analyze the effect of product quality, price perception, advertising and distribution channels on purchasing decisions for personal health devices. In addition, this study also aims to determine the dominant factors that influence purchasing decisions for medical devices. This research was conducted in Denpasar City by taking a research sample of 100 (one hundred) people using purposive sampling technique. This study uses multiple linear regression analysis techniques, t test and F test and test of determination. The result of the research is product quality, price perception has a positive and significant effect on purchasing decisions, while distribution channels have no significant effect on purchasing decisions. The implication of this research is that manufacturers who provide medical devices must be able to carry out price strategies in improving purchasing decisions and controlling market share in the health industry.