Obvious Peak Research Articles

Modified soil scattering coefficients for organic matter inversion based on Kubelka-Munk theory

The existing research into soil component inversion based on spectroscopic techniques has mainly focused on traditional statistical learning. However, the most prominent drawback of this approach is the difficulty in obtaining the soil components’ sensitive bands with explanatory inversion mechanisms. Whether for soil organic matter inversion or soil heavy metal inversion, there is still a lack of inversion models based on the physical theory of remote sensing. Hence, in this paper, an inversion model based on thickness correction using Kubelka-Munk (K-M) theory is proposed. Firstly, in this study, a soil thickness observation experiment based on K-M theory was undertaken. The impact of the soil thickness and the material of the container on the spectra was explored by selecting different experimental samples with different background container materials. A modified K-M thickness model was then developed by combining indoor spectral data. This allows the corresponding scattering coefficients and absorption coefficients for soil samples with different organic matter contents to be calculated. The optimal organic matter inversion model can then be constructed by the scattering coefficients, with the sensitive band at 2.197 μm. The results obtained in this study demonstrate the feasibility and superiority of the proposed method and further explain the sensitive bands of soil organic matter in hyperspectral data, with a determination coefficient accuracy of up to 0.97. The experimental results also demonstrate that the recommended soil thickness for soil samples should be more than 7 mm. In addition, when selecting background container materials, materials with obvious reflectance peak and valley characteristics should be avoided.

Modeling of reducing NH4NO3 in PM2.5 under high ammonia emission in urban areas: Based on high-resolution data

At present, the air quality in urban areas in China has continued to improve, but PM2.5 is still severely polluted in autumn and winter and is difficult to meet the Chinese standard. With the renovation of coal-fired boilers and the transformation of ultra-low emissions in factories, NO3− has gradually become the main inducing species for high levels of PM2.5. In this study, a high-resolution (1 h) online instrument was used to analyze the characteristics of atmospheric PM2.5 in the autumn and winter periods from October 2019 to February 2020 at Zhengzhou University in Zhengzhou. The inorganic nitrate in PM2.5 mainly existed in the form of semivolatile NH4NO3, and the method of reducing NH4NO3 was studied through data analysis. The basic method of reducing particulate nitrate in PM2.5 is not only to reduce nitrate precursors (NOx) but also to transform particulate nitrate into gas by reducing the aerosol pH value (enhancing aerosol acidity). The simulation analysis of NHx (NHx = NH3+NH4+), NO3T (NO3T=HNO3+NO3−), and SO42− reduction using the thermodynamic model ISORROPIA-II revealed that total ammonia (TA) has an obvious peak clipping effect on particulate NO3− when it is reduced by 60% and can effectively reduce NH4NO3 in PM2.5. The reliability and credibility of the data results were enhanced through long-term observation and local time analysis, and reducing TA and NO3− in areas with high ammonia emissions was proven to be feasible. This study is beneficial for formulating measures to reduce the average annual concentration of PM2.5 in ammonia-rich areas.

Quality maintenance of 1‐Methylcyclopropene combined with titanium dioxide photocatalytic reaction on postharvest cherry tomatoes

This study explored the effects of 1-MCP combined with TPC treatment on bioactive compounds, odor, and ultrastructure of cherry tomatoes during postharvest storage. The results showed that the three treatments could all maintain the firmness, soluble solids, and titratable acidity content. It was noteworthy that TPC applied to cherry tomatoes had positive effects on removing off-flavors and reducing accumulation of malondialdehyde, and it can better retain the lycopene content compared with 1-MCP in the later storage period. In addition, the combined treatment was more effective than the control check, single 1-MCP and single TPC, which can inhibit the respiration and ethylene production of cherry tomatoes, maintain the ascorbic acid content, and sustain the integrity of peel and pulp cell structure during postharvest storage. Our study concluded that 1-MCP + TPC was a feasible technology that can enhance the effect of single 1-MCP treatment and make up for the limitations of single treatment. Practical applications The moisture content of cherry tomatoes is higher than 90% so that cherry tomatoes are prone to softening, rot, and quality deterioration after harvest. They are typical climacteric fruits with obvious respiratory peaks. In the process of postharvest transportation and storage, intricate physiological and biochemical reactions occur in cells. A growing number of studies had shown that 1-Methylcyclopropene had certain limitations. We used combined treatment, in order to enhance the effect of single 1-Methylcyclopropene treatment and better guarantee the edible value and commodity value of postharvest cherry tomatoes. Our research showed that 1-Methylcyclopropene combined with titanium dioxide photocatalytic treatment may become an advanced preservation technology, and can provide a new idea for improving the storage quality of postharvest cherry tomatoes.

CELF1 promotes matrix metalloproteinases gene expression at transcriptional level in lens epithelial cells

BackgroundRNA binding proteins (RBPs)-mediated regulation plays important roles in many eye diseases, including the canonical RBP CELF1 in cataract. While the definite molecular regulatory mechanisms of CELF1 on cataract still remain elusive.MethodsIn this study, we overexpressed CELF1 in human cultured lens epithelial SRA01/04 cells and applied whole transcriptome sequencing (RNA-seq) method to analyze the global differences mediated by CELF1. We then analyzed public RNA-seq and CELF1-RNA interactome data to decipher the underlying mechanisms.ResultsThe results showed that transcriptome profile was globally changed by CELF1 overexpression (CELF1-OE). Functional analysis revealed CELF1 specifically increased the expression of genes in extracellular matrix disassembly, extracellular matrix organization, and proteolysis, which could be classified into matrix metalloproteinases (MMPs) family. This finding was also validated by RT-qPCR and public mouse early embryonic lens data. Integrating analysis with public CELF1-RNA interactome data revealed that no obvious CELF1-binding peak was found on the transcripts of these genes, indicating an indirectly regulatory role of CELF1 in lens epithelial cells.ConclusionsOur study demonstrated that CELF1-OE promotes transcriptional level of MMP genes; and this regulation may be completed by other ways except for binding to RNA targets. These results suggest that CELF1-OE is implicated in the development of lens, which is associated with cataract and expands our understanding of CELF1 regulatory roles as an RNA binding protein.

Estimation of a eutectic composition of imidazolium chloride ionic liquids using video imaging and impedance methods

The eutectic temperature Te and composition Xe of binary systems composed of three ionic liquids, 1-ethyl-3-methylimidazolium chloride ([C2mim]Cl), 1-methyl-3-propylimidazolium chloride ([C3mim]Cl), and 1-butyl-3-methylimidazolium chloride ([C4mim]Cl), were estimated using a video imaging method, in which the formation of a liquid phase on solidified ionic liquids at a given composition stored in a vial was detected from time-lapse images taken during temperature scanning. The advantage of this method is that multiple samples (five samples in this study) could be measured simultaneously, whereas its disadvantage is a less accurate determination of the melting point compared with the conventional differential scanning calorimetry (DSC) method. The Te and Xe of [C2mim]Cl–[C3mim]Cl, [C2mim]Cl–[C4mim]Cl, and [C3mim]Cl–[C4mim]Cl binary systems were roughly estimated. Furthermore, the Te of the ternary system of the [C2mim]Cl–[C3mim]Cl–[C4mim]Cl with limited compositions was estimated, which was lower than that of the binary systems. The transition of the electrochemical impedance of [C2mim]Cl ionic liquids was also measured using two Pt wire electrodes as a function of temperature. The differential inversed resistance curve (dR–1/dT)-T shows an obvious peak corresponding to the phase transition from a low conductive solid phase to a highly conductive liquid phase. This peak was comparable with the peak obtained in the DSC measurement.

Impact of Regional Climate Change on the Development of Lithium Resources in Zabuye Salt Lake, Tibet

Climate change has important implication for the ecological environment and human social activities. The Qinghai-Tibet Plateau is a sensitive area for climate change, and the lakes on the Qinghai-Tibet Plateau are known as the “guardians” of climate change. However, there are few studies on the impact of climate variations on the exploitation of lithium resources in salt lakes. In this work, the collected data from Zabuye Salt Lake Observation Station and the experimental data of brine at different temperatures were employed as the research objects to investigate the relationship between regional climate change and lithium resources in salt lakes. The results indicated that Zabuye Salt Lake had abundant solar energy resources from 1991 to 2020 with the annual average sunshine duration of 3,122.4 h, the average annual evaporation of 2,579.07 mm/yr, and the annual average precipitation of 168.65 mm/yr. The average annual evaporation is around 15.3 times the average annual precipitation, owing to the short rainy season and the low rainfall. The phase diagram displayed that two lithium carbonate precipitation peaks clearly appeared at 25°C, and no obvious precipitation peak appeared at 15°C, indicating that a high-grade lithium carbonate mixed salt was prone to be formed at a higher temperature while lithium ions was more inclined to enrich in brine at a lower temperature. Therefore, Zabuye Salt Lake with the characteristics of low temperature, large temperature difference, less precipitation, strong radiation and large evaporation could be applied as unique lithium resources in the salt gradient solar pond, which would play a positive role in the development of salt lake resources.

In Situ Monitoring of Transmetallation in Electric Potential-Promoted Oxidative Coupling in a Single-Molecule Junction

In Situ Monitoring of Transmetallation in Electric Potential-Promoted Oxidative Coupling in a Single-Molecule Junction

Controllable synthesis of multicolor Alq3:DCM single-crystalline microrods for optical waveguides

It has been demonstrated that organic semiconductor micro-/nanocrystals with multicolor emission/waveguide characterizations would be widely utilized as ideal building blocks for the next generation of miniaturized optical, electronic and logic operation devices. However, rational synthesis of one dimensional micro-/nanocrystals with multicolor emission and optical waveguide performances are highly desirable and still remain a challenge. Here, the DCM doped Alq 3 single-crystalline microrods are fabricated via a facile solution-exchange method. It is found that a redshift in light-emission frequency is extremely sensitive to the doping concentration of 4-(dicyano-methylene)-2-methyl-6-(4-dimethylamino-styryl)-4Hpyran (DCM) guest molecule. The green emission at 527 nm of Alq 3 is the main emitting peak when doping concentration of DCM in Alq 3 :DCM is less than 150:1. Then, when the doping concentration of DCM in Alq 3 :DCM is larger than 100:2 such as 100:10, the red emission at 635 nm becomes the dominant emitting peak, the redshift amounts can reach to roughly 108 nm. In addition, the DCM-doped Alq 3 microrods exhibit a lower optical loss of 0.019 dB/μm as a multicolored waveguide material. Therefore, it is demonstrated that the DCM-doped organic micro/nano crystals can be utilized as a promising building block for various optoelectronic components. Herein, the DCM doped Alq 3 single-crystalline microrods were controllably fabricated via a facile solution-evaporation method. It is found that a redshift in light-emission frequency is extremely sensitive to the dopant concentration of DCM guest molecule. Interestingly, when the doped ratio of Alq 3 to DCM are 100:1 and 100:1.5, there is an obvious peak at 557 nm, besides, a weak peak at 613 nm appears. In addition, the DCM:Alq 3 microrods exhibits a lower optical loss of 0.019 dB/μm as a waveguide material. • The DCM doped Alq 3 single-crystalline microrods are fabricated firstly via a facile solution-exchange method. • The light-emission frequency is highly sensitive to the doping concentration of DCM guest molecule. • The DCM-doped Alq 3 microrods exhibits a lower optical loss of 0.019 dB/μm as a multicolored waveguide material.

Ratiometric electrochemical immunoassay for procalcitonin based on dual signal probes: Ag NPs and Nile blue A.

In order to determineprocalcitonin, a sandwich-type ratiometic electrochemical immunosensor was developed by differential pulse voltammetry (DPV).Dueto high chemical stability and good biocompatibility, graphitic carbon nitride (g-C3N4) could be used as feasible supporter to carry silver nanoparticles (Ag NPs) with an obvious oxidative peak (measured typically at + 0.3V vs. SCE). Ag NPs loaded onto g-C3N4 were not only beneficial to prevent the agglomeration of Ag NPs, but also favorable to improve the electron transfer velocity of g-C3N4. Moreover, the g-C3N4-Ag NPs as the matrix could immobilize primary antibody by Ag-N bond. Nile blue A (NBA), an excellent redox probe based on the redox reaction with two-electrons, provides a current signal at - 0.38V (vs. SCE). Zr-based metal organic framework (UiO-67), an ideal framework material with large specific surface area and high porosity, could absorb the substantial water-soluble NBA by electrostatic adsorption. TheUiO-67 modified by NBA (NBA-UiO-67) owned admirable biocompatibility and was a qualifying marker to load the secondary antibody. For the immunosensor, the current ratio of NBA to Ag NPs (INBA/IAg NPs) was increased as the concentrations of PCT increased. Under the optimum conditions, the linear range of the immunosensor was 0.005 to 50ng/mL; the detection limit was 1.67pg/mL (S/N = 3), which reflected the excellent analytical performance of the sensor. The proposed immunosensor strategy isa simple and dependable platform, with great application potential in biometric analysis.

Strength, Microstructure, and Deformation Behavior of Frozen Cemented Tailing Material

Cemented paste backfill (CPB) is a novel cementitious construction material that is used extensively for underground mine support and/or mine waste management worldwide. CPB consists of a mix of tailings (mine waste), water, and binder. In other words, tailings are transformed into construction materials. Key engineering properties required for the geotechnical design of CPB structures include strength and deformation behavior. However, there is a paucity of technical data and information about the effect of sub-zero temperatures on these properties. This paper presents an experimental study that focuses on the investigation of the influence of sub-zero curing temperatures on the strength, deformation behavior, and microstructure (e.g., pore structure, porosity, and binder hydration products) of CPB. Several CPB samples with various combinations of compositions (e.g., binder type, cement amount, and water content) cured at different temperatures (sub-zero and room temperatures) and times (7–90 days) are tested with regard to strength, stress–strain behavior, and microstructural characteristics. It is found that frozen CPB (FCPB) exhibits remarkable strength compared with unfrozen CPB and has a great resemblance to frozen soil. No obvious peak stress is observed from FCPB samples during compression, and strain hardening phenomena are commonly seen after the initial yield point. Factors that may affect the behavior of FCPB are thoroughly examined. Binder contents and types are found to be irrelevant; in contrast, water content plays a dominant role. This negligible effect of binder on the properties of FCPB is due to the inhibition of the binder hydration by sub-zero curing temperatures. FCPBs show coarser pore structure than unfrozen CPBs. The results obtained in this study have significant practical engineering applications for mines located in permafrost or cold regions.

A noninvasive and comprehensive method for continuous assessment of cerebral blood flow pulsation based on magnetic induction phase shift.

Cerebral blood flow (CBF) monitoring is of great significance for treating and preventing strokes. However, there has not been a fully accepted method targeting continuous assessment in clinical practice. In this work, we built a noninvasive continuous assessment system for cerebral blood flow pulsation (CBFP) that is based on magnetic induction phase shift (MIPS) technology and designed a physical model of the middle cerebral artery (MCA). Physical experiments were carried out through different simulations of CBF states. Four healthy volunteers were enrolled to perform the MIPS and ECG synchronously monitoring trials. Then, the components of MIPS related to the blood supply level and CBFP were investigated by signal analysis in time and frequency domain, wavelet decomposition and band-pass filtering. The results show that the time-domain baseline of MIPS increases with blood supply level. A pulse signal was identified in the spectrum (0.2–2 Hz in 200–2,000 ml/h groups, respectively) of MIPS when the simulated blood flow rate was not zero. The pulsation frequency with different simulated blood flow rates is the same as the squeezing frequency of the feeding pump. Similar to pulse waves, the MIPS signals on four healthy volunteers all had periodic change trends with obvious peaks and valleys. Its frequency is close to that of the ECG signal and there is a certain time delay between them. These results indicate that the CBFP component can effectively be extracted from MIPS, through which different blood supply levels can be distinguished. This method has the potential to become a new solution for non-invasive and comprehensive monitoring of CBFP.

Non-isothermal crystallization kinetics and rheological behaviors of PBT/PET blends: effects of PET property and nano-silica content

ABSTRACT PBT and PET are subjected to thermal-oxidative degradation and thermomechanical degradation during the process of melt blending, which affect the polymer structure and properties. The effect of feed properties of PET and the addition of modified nanoparticles on blends are a question worthy of discussion. This work describes the melting and thermal stability, the crystallization behavior and non-isothermal crystallization kinetic, the rheological behaviors and mechanical properties of several PBT/PET blends prepared by twin-screw melt extrusion. Results show that the molecular chain of the polyester blends obtained by stable extrusion are not significantly degraded, there is only one obvious melting peak and crystallization peak on the thermal analysis curves, and the melting point is lower than either of the two polyesters. An appropriate amount of SD can effectively reduce the crystallization rate of the PBT material and extend the crystallization time. The rheological behavior of PBT/PET blends is complicated than PET raw materials and SD, as well as the melt processing temperature and shear rate will all affect the rheological behavior of the blends. For example, at low shear rate, polyester blends with SD exhibit strong shear thinning behavior. In general, the SD content affects the rheological property of blends in a way similar to the law of influence on crystallization behavior. When SD content is 0.3 wt%, a polyester product with higher elongation at break than pure PBT can be obtained. This can provide a useful reference for preparing commercialized polyester blend products with good melt processability and elongation by simple blending.

Improving oxygen reduction reaction of microbial fuel cell by titanium dioxide attaching to dual metal organic frameworks as cathode

In this study, a two-step simple distributed feeding method was used to prepare the core–shell nanocomposite dual metal organic frameworks (D-MOFs, TiO2@ZIF-67/ZIF-8). There were three obvious peaks (011), (112), (222) interface in D-MOFs core, which fully showed that ZIF-67/ZIF-8 crystal core was successfully synthesized. The morphology of composite material was core–shell structure with a rough surface, and Ti, Co, Zn, Al were uniformly distributed on the surface. TiO2@ZIF-67/ZIF-8 also had excellent electrochemical activity and the maximum power density of TiO2@ZIF-67/ZIF-8 microbial fuel cell (MFC) was 341.506 mW/m2, which was 1.30 times of ZIF-67/ZIF-8-MFC (262.144 mW/m2) and 2.07 times of ZIF-67-MFC (164.836 mW/m2). And the continuous output voltage of TiO2@ZIF-67/ZIF-8-MFC was 413.43 mV, which could maintain stable voltage output for 8.3 days. D-MOFs as the core of composites ensured the integrity, stability and high activity of materials; Rough TiO2 as the surface of the material provided surface area and reaction center.

Smith–Purcell radiation improved by multi-grating structure

The photonic crystal structure has attracted much attention due to its ability to confine light. In this paper, we present our study on an improved Smith–Purcell radiation from a simple metal photonic crystal excited by moving electrons. Different from the wide-band Smith–Purcell radiation from a single metal grating, the results show that the injected electrons could induce more dipole oscillations inside the multi-grating structure, and it leads to the enhancement of the radiation intensity. In addition, there are strong resonances in metal multi-grating structure, and the resonance characteristics may narrow the radiation band, which leads to a radiation with an obvious peak in the spectrum. Therefore, the multi-grating structure has the ability to enhance the radiation intensity and shape the radiation frequency band. By optimizing the structure parameters, coherent and tunable Smith–Purcell radiation can be realized, and it provides a potential way to develop band-controllable light or THz radiation source.

The inactivation effects and mechanisms of Karenia mikimotoi by non-metallic elements modified TiO2 (SNP-TiO2) under visible light

As an advanced oxidation technology, photocatalytic treatment of red tide algae pollution was potential of great research prospects. However, the most commonly used photocatalyst TiO2 can only use ultraviolet light with short wavelength because of its wide band gap. In this study, the non-metallic elements S, N and P were added into the TiO2 (SNP-TiO2) lattice by hydrothermal synthesis, and the inactivation effects and mechanisms of Karenia mikimotoi were studied under visible light. The particle size of the obtained photocatalyst was about 10 nm. There were obvious characteristic peaks at the (101) (004) (200) (105) (211) (204) interface and included NO bond, PO bond and SO bond. The incorporation of S, N and P reduced the band gap of TiO2 from 3.2 eV to 3.08 eV, which showed the integrity of the doping process. S0.7N1.4P0.05-TiO2 was full of excellent photocatalytic activity, the continuous inhibition effect was the most obvious. When exposed to 200 mg/L for 96 h, the growth inhibition rate (IR) was 81.8%. Photocatalytic process led to membrane damage of algal cells and collapse of photosynthetic system, caused oxidative stress response and accelerated algal cell inactivation. The study indicated that non-metallic elements modified TiO2 (SNP-TiO2) was full of potential of in treating red tide outbreak pollution under visible light.

Vehicular Emissions Enhanced Ammonia Concentrations in Winter Mornings: Insights from Diurnal Nitrogen Isotopic Signatures.

A general feature in the diurnal cycle of atmospheric ammonia (NH3) concentrations is a morning spike that typically occurs around 07:00 to 10:00 (LST). Current hypotheses to explain this morning's NH3 increase remain elusive, and there is still no consensus whether traffic emissions are among the major sources of urban NH3. Here, we confirmed that the NH3 morning pulse in urban Beijing is a universal feature, with an annual occurrence frequency of 73.0% and a rapid growth rate (>20%) in winter. The stable nitrogen isotopic composition of NH3 (δ15N-NH3) in winter also exhibited a significant diurnal variation with an obvious morning peak at 07:00 to 10:00 (-18.6‰, mass-weighted mean), higher than other times of the day (-26.3‰). This diurnal pattern suggests that a large fraction of NH3 in the morning originated from nonagricultural sources, for example, power plants, vehicles, and coal combustion that tend to have higher δ15N-NH3 emission signatures relative to agricultural emissions. In particular, the contribution from vehicular emissions increased from 18% (00:00 to 07:00) to 40% (07:00 to 10:00), while the contribution of fertilizer sources to NH3 was reduced from 15.8% at 00:00 to 07:00 to 5.2% at 07:00 to 10:00. We concluded that NH3 concentrations in winter mornings in urban Beijing were indeed enhanced by vehicle emissions, which should be considered in air pollution regulations.

An Improved Algorithm for Peak Detection Based on Weighted Continuous Wavelet Transform

Peak detection is a crucial preprocessing step in the analysis of various spectral signals. The method based on the continuous wavelet transform is more practical and popular, and has better detection accuracy and reliability by identifying peaks across scales in the wavelet space and implicitly removing noise as well as the baseline. However, there are inevitably overlapping peaks in the measured spectra, and the formed composite ridges affect peak detection accuracy. Most peak detection methods have limited applicability to overlapping peaks. A weighted continuous wavelet transform (WCWT) peak detection algorithm is proposed to improve the adaptive ability of the peak detection method. This method yields more obvious spectral peak characteristics in low-scale regions. Composite ridges can be successfully truncated by setting a noise threshold based on the standard deviation of the spectral signal. In addition, the maximum value in the ridges was compressed and shifted to a smaller scale, which could determine the peaks more accurately. The method was applied to the peak detection of simulated spectra, Romanian database of Raman spectra, and real liquid electrode glow discharge spectra. The results show that the proposed method exhibits good peak detection performance.

亚热带岩溶区典型常绿和落叶树种的蒸腾特征及其对环境因子的响应

植物蒸腾是水循环的重要组成部分，为了解亚热带岩溶区树木的蒸腾耗水情况，探究气候和水文地质条件对植物蒸腾的影响，运用Granier热耗散探针技术，对亚热带岩溶区次生林内的常绿树种女贞（L.lucidum）和落叶树种刺槐（R.pseudoacacia）的树干液流进行了连续监测，并同步监测了气象因子及土壤含水率（SMC），探讨在不同时间尺度下两种生活型树种的蒸腾特征及其对环境因子的响应。结果表明：（1）在季节尺度下，影响两树种整树蒸腾量（ET）的主要因子为太阳辐射强度（Rs）、气温（T）和水汽压亏缺（VPD）；女贞蒸腾量（ET_L）表现为夏季（1.29 kg/h） > 春季（0.57 kg/h） > 冬季（0.15 kg/h） > 秋季（0.13 kg/h），刺槐蒸腾量（ET_R）表现为夏季（0.90 kg/h） > 春季（0.31 kg/h） > 秋季（0.16 kg/h） > 冬季（0.04 kg/h）。（2）在日尺度下，晴天两树种ET呈现出明显的单峰日变化，且主要影响因子均为T、VPD和Rs；但由于常绿和落叶树种的生理特征差异，降雨时ET_L受到抑制，而ET_R则显著提升。（3）从昼夜层面来看，两树种夜间蒸腾量不足日蒸腾总量的35%。在夜雨现象和树木生理特征的影响下，秋冬季夜间蒸腾量占比明显高于春夏季，刺槐的平均夜间蒸腾量及其占比（1.56 kg，24.1%）高于女贞（1.08 kg，13.9%）。;Plant transpiration is an important part of water cycle in ecosystem, that is, the process of water transfer from soil to atmosphere through plants. It is driven by solar radiation, air temperature, air humidity and wind speed, and also affected by soil water storage capacity. Understanding and quantifying the influence mechanism of transpiration is an important basis to explore the water consumption of vegetation and the water balance of ecosystem. However, although the climate conditions in the subtropical karst area are good, there is a drought period of 4-5 months. At the same time, plants are often affected by water stress because of the thin soil layer and low water holding capacity of soil in karst area. The study of plant transpiration characteristics helps us understand the water consumption of trees in subtropical karst areas, and is also of great significance for exploring the impact of climate and hydro-geological conditions on plant transpiration. Granier's thermal dissipation probe method was used to continuously monitor the trunk sap flow of the evergreen tree species (L.lucidum) and the deciduous tree species (R.pseudoacacia) in the secondary forest in the subtropical karst area. The meteorological factors and soil moisture content (SMC) are also monitored simultaneously. Our purpose is to analyze the transpiration characteristics of two life-form tree species and their responses to environmental factors on different time scales. The results show that:(1) at the seasonal scale, the main factors affecting the whole-tree transpiration (ET) are solar radiation intensity (Rs), air temperature (T) and vapor pressure deficiency (VPD). The transpiration of L.lucidum (ET_L) is shown as summer (1.29 kg/h) > spring (0.57 kg/h) > winter (0.15 kg/h) > autumn (0.13 kg/h), transpiration of R.pseudoacacia (ET_R) is shown as summer (0.90 kg/h) > spring (0.31 kg/h) > autumn (0.16 kg/h) > winter (0.04 kg/h). (2) On the daily scale, the ET of the two tree species shown obvious single peak curve on sunny day, and the main factors affecting transpiration are T, VPD and Rs. However, due to the differences in the physiological characteristics of evergreen and deciduous tree species, ET_L is weakened during rainfall, while ET_R is significantly increased. (3) in terms of day and night, the nocturnal transpiration of the two tree species accounts for less than 35% of the total daily transpiration on average. Affected by the phenomenon of night precipitation and the physiological characteristics of trees, the proportion of nocturnal transpiration in the autumn and winter is significantly higher than that in the spring and summer. At the same time, the average daily nocturnal transpiration and its proportion of R.pseudoacacia (1.56 kg, 24.1%) is higher than that of L.lucidum (1.08 kg, 13.9%).

Impact of COVID-19 Prevention and Control on the Influenza Epidemic in China: A Time Series Study.

Background. COVID-19 prevention and control measures might affect influenza epidemic in China since the nonpharmaceutical interventions (NPIs) and behavioral changes contain transmission of both SARS-CoV-2 and influenza virus. We aimed to explore the impact of COVID-19 prevention and control measures on influenza using data from the National Influenza Surveillance Network.Methods. The percentage of influenza-like illness (ILI%) in southern and northern China from 2010 to 2022 was collected from the National Influenza Surveillance Network. Weekly ILI% observed value from 2010 to 2019 was used to calculate estimated annual percentage change (EAPC) of ILI% with 95% confidence intervals (CIs). Time series analysis was applied to estimate weekly ILI% predicted values in 2020/2021 and 2021/2022 season. Impact index was used to explore the impact of COVID-19 prevention and control on influenza during nonpharmaceutical intervention and vaccination stages.Results. China influenza activity was affected by the COVID-19 pandemic and different prevention and control measures during 2020-2022. In 2020/2021 season, weekly ILI% observed value in both southern and northern China was at a low epidemic level, and there was no obvious epidemic peak in winter and spring. In 2021/2022 season, weekly ILI% observed value in southern and northern China showed a small peak in summer and epidemic peak in winter and spring. The weekly ILI% observed value was generally lower than the predicted value in southern and northern China during 2020-2022. The median of impact index of weekly ILI% was 15.11% in north and 22.37% in south in 2020/2021 season and decreased significantly to 2.20% in north and 3.89% in south in 2021/2022 season.Conclusion. In summary, there was a significant decrease in reported ILI in China during the 2020-2022 COVID-19 pandemic, particularly in winter and spring. Reduction of influenza virus infection might relate to everyday Chinese public health COVID-19 interventions. The confirmation of this relationship depends on future studies.

Na3V2(PO4)2F3@bagasse carbon as cathode material for lithium/sodium hybrid ion battery.

The nano-scale spherical Na3V2(PO4)2F3 with a NASICON structure phase was prepared with a spray drying technique, and the bagasse in Guangxi, China was selected as the carbon source to prepare Na3V2(PO4)2F3/C. The optimal preparation conditions of the composite determined using thermogravimetry, X-ray diffraction, scanning electron microscopy and electrochemical testing were: a calcination temperature of 650 °C and a 20% carbon source. The Na3V2(PO4)2F3/C has obvious redox peaks, determined by cyclic voltammetry (CV), at 3.90 V and 3.75 V, 4.32 V and 4.15 V. These two pairs of redox peaks correspond to the escape/intercalation of the two pairs of Li+/Na+. Notably, compared with pure Na3V2(PO4)2F3, the specific discharge capacity of Na3V2(PO4)2F3/C-20%, which were used as a cathode material for lithium-sodium hybrid ion batteries, increased from 55 mA h g-1 to 125 mA h g-1, which was an improvement of twofold.