Climate state of the Three Gorges Region in the Yangtze River basin in 2022–2023

Based on daily observation data of the Three Gorges Region(TGR)of the Yangtze River basin and global reanalysis data,the climate characteristics,climate events,and meteorological disasters of the TGR in 2022 and 2023 were analyzed.For the TGR,the average annual temperature for 2022 and 2023 was 0.8℃ and 0.4℃ higher than normal,respectively,making them the two warmest years in the past decade.In 2022,the TGR experienced its warmest summer on record.The average air temperature was 2.4℃ higher than the average,and there were 24.8 days of above-average high temperature days during summer.Rainfall in the TGR varied significantly between 2022 and 2023.Annual rainfall was 18.4%below normal and drier than normal in most parts of the region.In contrast,the precipitation in 2023 was considerably higher than the long-term average,and above normal for almost the entire year.The average wind speed exhibited minimal variation between the two years.However,the number of foggy days and relative humidity increased in 2023 compared to 2022.In 2022–2023,the TGR mainly experienced meteorological disasters such as extreme high temperatures,regional heavy rain and flooding,overcast rain,and inverted spring chill.Analysis indicates that the abnormal western Pacific subtropical high and the abnormal persistence of the eastward-shifted South Asian high were the two important drivers of the durative enhancement of record-breaking high temperature in the summer of 2022.

Development and Application of Ultrafast Circular Dichroism Spectroscopy Techniques

Chirality hold broad applications in life sciences,quantum devices,and various other areas.Traditionally,molecular chirality can be characterized by using steady-state circular dichroism spectroscopy.However,the techniques that can characterize excited state chirality are progressively capturing the public interest as it can provide the dynamic information for chirality generation and transfer.In this review,we focus on the theoretical background and the developmental history of femtosecond time-resolved circular dichroism spectroscopy(TRCD)techniques around the world.Additionally,we provide examples to showcase the utility of these techniques in the analysis of the dynamical molecular chemical structures,the investigation of molecular chirality generation,and the detection of electron spin dynamics in semiconductor quantum dots.

槲皮素通过影响Nrf2-Keap1信号通路减缓镉中毒大鼠的生殖机能损伤

本试验旨在探索联合使用槲皮素(QE)可以减轻镉(Cd)致雄性大鼠生殖系统损伤及在此过程Nrf2-Keap1信号通路发挥的作用。试验选取32只3月龄、体重相近的SPF级Wistar雄性大鼠,随机分为4组,每组8只,分别为对照组[0.5mL·(kg·d)^(-1)生理盐水]、Cd组[5mg·(kg·d)^(-1) CdCl_2]、QE组[15mg·(kg·d)^(-1) QE]、Cd+QE组[5mg·(kg·d)^(-1) CdCl_2+15mg·(kg·d)^(-1) QE],连续灌胃1个月。试验结束后,计算各组大鼠睾丸及附睾脏器系数,检测精子质量及睾丸组织抗氧化水平等变化,利用RT-qPCR及Western blot法检测Nrf2及其相关基因mRNA和蛋白的表达。结果表明:与对照组相比,Cd组大鼠生殖机能受损严重。与Cd组相比,Cd+QE组大鼠睾丸附睾脏器系数(P<0.01)和睾酮分泌量(P<0.05)增加明显;精子质量提高;睾丸组织中MDA、H_2O_2含量极显著降低(P<0.01),GSH含量(P<0.05)和CAT、T-SOD、GSH-Px酶活性(P<0.01)明显提高;Nrf2及其相关基因NQO1、γ-GCS、HO-1、GSH-Px的mRNA和蛋白的表达呈现明显上升趋势(P<0.01或P<0.05),而Keap1基因和蛋白质的表达显著降低(P<0.05)。综上,QE可能通过激活Nrf2-Keap1信号通路有效减轻Cd引起的大鼠生殖系统损伤。

华北雨季降水年代际变化与水汽输送的联系

本文基于1961~2018年华北地区均一化逐日降水资料和ECMWF(欧洲中期天气预报中心)ERA5全球再分析环流资料,采用一种综合考虑降水量和西太平洋副热带高压脊线影响的雨季监测标准,计算了华北雨季起讫日期和降水量,在此基础上讨论了华北雨季季节内进程的水汽输送特征。重点分析了降水量与水汽收支的年代际变化关系,揭示了水汽输送的时空变化规律及其对华北雨季降水的影响。研究结果表明:(1)华北雨季每年的起讫日期不同,从而每年雨季发生时段和季节内进程不同。(2)降水的形成与水汽输送及其辐合密切相关,有四个水汽通道维持华北雨季降水,即印度季风水汽、东亚季风水汽、110°E~120°E之间越赤道气流向北的水汽输送和40°N附近中纬度西风带水汽。(3)华北雨季降水和净水汽收支具有相似的年代际变化特征,分别在1977、1987、1999年发生突变,总体呈现“减—增—减”的阶段性变化趋势,两者位相转变相关性很强。(4)水汽输送的强弱和到达华北时间的早晚均对雨季降水多寡有重要影响。华北多雨年代与少雨年代水汽通量有明显的差异,主要表现在:在多雨年代,西北太平洋为反气旋式环流异常,偏南水汽强盛,并且与中高纬西风带异常偏西水汽汇聚于华北,华北地区水汽辐合偏强;考虑季节内进程,水汽到达华北的时间早、强度大,停留时间长、辐合强,减弱的时间晚;而在少雨年代,我国东北地区、朝鲜半岛及日本海附近为气旋式环流异常,华北地区由南向北的水汽输送偏弱,水汽辐散明显加强;季节内进程表现出与多雨年代相反的特征。(5)考虑华北地区四个边界的水汽收支,南边界和西边界有最大、次大水汽输入,二者的年代际变化是影响雨季降水年代际变化的重要因素。在多雨年代,南边界和西边界水汽净输入很强,但北边界的输出也很强;在少雨年代,南边界和西边界水汽净输入很弱,但北边界转为输入,这是区别于多雨年代的重要特征。

赭曲霉毒素A免疫毒性研究进展

赭曲霉毒素A(OTA)是一类免疫抑制类真菌毒素,主要由曲霉属和青霉属等产毒真菌产生。OTA作为食品和饲料原料的一种常见污染物,在各种粮食作物及其副产品中广泛存在,其自身的免疫毒性效应对动物生产和人类健康造成极大的危害,由此引起人们的高度关注。赭曲霉毒素在饲料中广泛存在,饲料中的OTA对动物危害严重,诱发机体产生严重的免疫毒性,但其具体机制目前尚未完全清楚。论文就OTA对动物器官免疫、非特异性免疫、特异性免疫的研究现状进行综述,为深入研究OTA对动物免疫机能的损害机制提供参考依据。

Climate observation of the Three Gorges Region of the Yangtze River in 2019

This report provides a broad overview of the climate and the major weather and climate events over the Three Gorges Region of the Yangtze River(TGR)in 2019.The year 2019,a 0.3℃ warmer year than normal,had a colder winter and warmer spring,summer,and autumn.Annual precipitation in 2019 was 13%less than normal.Below average normal rainfall amounts were received in all four seasons,with 28%and 16%less-than-normal in winter and summer,respectively.The annual mean wind speed in the TGR was higher than normal,and relative humidity was near normal for all four seasons.The intensity of acid rain in 2019 was the weakest since 1999.The major climate events and meteorological disasters in the TGR in 2019 included heat waves,drought,and rainstorms.Heat waves occurred frequently and persisted for long durations.Summer and autumn drought occurred in central and eastern regions of the TGR.The autumn rains of West China occurred earlier this year,which brought much more rainfall than normal in central and western regions of the TGR.

State of the climate in the Three Gorges Region of the Yangtze River basin in 2020

In 2020,the average air temperature in the Three Gorges Region(TGR)of the Yangtze River basin was 17.2℃,which was close to normal,there were exceptionally fewer days than normal with high temperatures,and the high-temperature events mainly occurred in August.Meanwhile,the average precipitation was 1530.8 mm,which was a remarkable 29%more than usual,and the second-highest since 1961.The precipitation was obviously above-normal in summer,and the precipitation in both June and July was the second-highest of the same period in history.The average number of rainstorm days was higher than normal,and the second-highest since 1961.The average wind speed in the TGR was apparently higher than normal;the average relative humidity was slightly higher than normal;and there were no instances of acid rain,with the rain acidity showing a significant weakening trend over the previous 15 years.In the summer of 2020,the TGR experienced heavy rainstorms and flood disasters.Analysis shows that the frequent southward movement of cold air and abundant warm water vapor from the southwest were the direct causes of the abnormally high precipitation in the TGR from June to July.After the spring of 2020,the continuously high sea surface temperature in the Indian Ocean led to a continuously strong western Pacific subtropical high and its average location being situated more to the south than normal,which might have been an important cause for the abnormal climate conditions in the Yangtze River basin from June to July.

Analysis of climatic features and major meteorological disasters over the Three Gorges Region of the Yangtze River Basin in 2021

Based on daily observation data in the Three Gorges Region(TGR)of the Yangtze River Basin and global reanalysis data,the authors analyzed the climate characteristics and associated temporal variations in the main meteorological factors in 2021,as well as the year’s climatic events and meteorological disasters.The 2021 average temperature was 0.2℃above the 1991-2020 average and the 13 th-warmest year since 1961.Seasonally,winter and autumn were both warmer than usual.The annual mean precipitation was 12.8%above normal,and most regions experienced abundant rainfall throughout the year.The seasonal variation in precipitation was significant and the TGR had a wetter-than-normal spring and summer.The number of rainstorm days was higher than normal;the wind speed was above normal;and the relative humidity was higher than normal.In terms of rain acidity,2021 was tied with 2020 as the lowest since 1999.From mid-September to early October 2021,the TGR experienced exceptional high-temperature weather,which was driven by abnormal activity of mid-and high-latitude atmospheric circulation over the Eurasian continent and the western Pacific subtropical high(WPSH).In addition,a strong blocking high over the Ural Mountains accompanied by intense mid-latitude westerly winds prevented cyclonic disturbances from extending to the subtropical region.As a result,under the combined effect of the weaker-than-normal cold-air activities and the anomalous WPSH,the TGR experienced extreme high-temperature weather during early autumn 2021.

Controllable synthesis of a self-assembled ultralow Ru,Ni-doped Fe_(2)O_(3) lily as a bifunctional electrocatalyst for large-current-density alkaline seawater electrolysis

Highly efficient and stable bifunctional electrocatalysts that can be used for large-current-density electrolysis of alkaline seawater are highly desirable for carbon-neutral economies,but their facile and controllable synthesis remains a challenge.Here,self-assembled ultralow Ru,Ni-doped Fe_(2)O_(3) with a lily shaped morphology was synthesized on iron foam(RuNi-Fe_(2)O_(3)/IF)via a facile one-step hydrothermal process,in which the intact lily shaped RuNi-Fe_(2)O_(3)/IF was obtained by adjusting the ratio of Ru/Ni.Benefitting from the Ru/Ni chemical substitution,the as-synthesized RuNi-Fe_(2)O_(3)/IF can act as free-standing dual-function electrodes that are applied to electrocatalysis for the hydrogen evolution(HER)and oxygen evolution reactions(OER)in 1.0 mol L^(-1) KOH,requiring an overpotential of 75.0 mV to drive 100 mA cm^(-2) for HER and 329.0 mV for OER.Moreover,the overall water splitting catalyzed by RuNi-Fe_(2)O_(3)/IF only demands ultralow cell voltages of 1.66 and 1.73 V to drive 100 mA cm^(-2) in 1.0 mol L^(-1) KOH and 1.0 mol L^(-1) KOH seawater electrolytes,respectively.The electrodes show remarkable long-term durability,maintaining current densities exceeding 100 mA cm^(-2) for more than 100 h and thus outperforming the two-electrode system composed of noble catalysts.This work provides an efficient,economical method to synthesize self-standing bifunctional electrodes for large-current-density alkaline seawater electrolysis,which is of significant importance for ecological protection and energy exploitation.

Cold Start Problem of Vehicle Model Recognition under Cross-Scenario Based on Transfer Learning

As a major function of smart transportation in smart cities,vehicle model recognition plays an important role in intelligent transportation.Due to the difference among different vehicle models recognition datasets,the accuracy of network model training in one scene will be greatly reduced in another one.However,if you don’t have a lot of vehicle model datasets for the current scene,you cannot properly train a model.To address this problem,we study the problem of cold start of vehicle model recognition under cross-scenario.Under the condition of small amount of datasets,combined with the method of transfer learning,load the DAN(Deep Adaptation Networks)and JAN(Joint Adaptation Networks)domain adaptation modules into the convolutional neural network AlexNet and ResNet,and get four models:AlexNet-JAN,AlexNet-DAN,ResNet-JAN,and ResNet-DAN which can achieve a higher accuracy at the beginning.Through experiments,transfer the vehicle model recognition from the network image dataset(source domain)to the surveillance-nature dataset(target domain),both Top-1 and Top-5 accuracy have been improved by at least 20%.

UHPLC-MS/MS测定人血浆中尿嘧啶与二氢尿嘧啶的浓度

目的建立同时测定人血浆中尿嘧啶(U)和二氢尿嘧啶(UH_(2))含量的超高效液相色谱串联质谱(UHPLCMS/MS)方法。方法在Agilent 6460A串联质谱仪上采用正离子检测模式,以氯尿嘧啶为内标,3%牛血清蛋白为代血浆基质,样本经乙酸乙酯液液萃取后在Agilent poroshell 120 SB-Aq(2.1 mm×100 mm,2.7μm)色谱柱上采用梯度洗脱进行色谱分离。流动相为5 mmol/L醋酸铵水溶液和乙腈溶液;流速0.3 ml/min;柱温为30℃;进样量为5μl。结果尿嘧啶和二氢尿嘧啶的线性范围为10.0~1500.0 ng/ml,线性关系良好,其相关系数r>0.990,日内与日间精密度偏差均<15%。结论该方法操作简单、选择性好,可用于测定人血浆中尿嘧啶和二氢尿嘧啶的含量。

沼气工程残余物资源化利用探究

沼气工程在当前城镇化建设发展过程中发挥着积极作用,面对沼气工程中的残余物,需要积极开展合理有效的利用工作,切实提升其整体的使用价值和利用效率。本文主要从沼气工程残余物资源化利用的可行性分析入手,介绍了沼气工程沼液沼渣利用过程中存在的问题,提出利用沼气工程残余物的方式,对于切实有效提升沼液沼渣的总体利用价值提供一定借鉴和参考。

Determination of Nine Phenolic Components in Leaves of Crataegus pinnatifida Bge.

[Objectives] To determine the nine phenolic components in the leaves of Crataegus pinnatifida Bge. [Methods] The reversedphase high-performance liquid chromatography( RP-HPLC) was applied. [Results] Nine phenolic components showed a good linear relationship in the range of 2-500 μg/m L with r in the range of 0. 999 5-0. 999 9. The recovery rate of spiked samples ranged from 93. 7% to110. 2%,and the relative standard deviation was in the range of 0. 69%-4. 58%. The leaves of 29 cultivars of C. pinnatifida Bge. were measured,and the average content of the nine phenolic components was as follows: isoquercitrin,hyperoside,procyanidin C1,procyanidin D1,epicatechin,procyanidin B2,chlorogenic acid,eucomic acid,and vitexin 2 "-O-rhamnoside. The contents of flavonoids and phenolic acids were high,up to 15 mg/g D. W,and the content of procyanidins was up to 6 mg/g D. W. [Conclusions]This method is easy and accurate in determination of phenolic components in the leaves of C. pinnatifida Bge.

Biotransformation and pharmacological activities of platycosides from Platycodon grandiflorum roots

In Northeast China,Goubao pickle is a popular food fermented from the roots of Platycodon grandiflorum as the main material,offering a unique flavor and rich nutritional value.Platycosides in roots of P.grandiflorum may play a crucial role in determining the quality of Goubao pickle through microorganism fermentation.However,biotransfermation of platycosides has not been reviewed during fermentation.In this study,we reviewed platycosides in chemical diversity,metabolic processes in vivo,biotransformation of platycosides in vitro,and pharmacological effects.Finally,we also discussed how to improve the bioactive secondary platycosides we desire by regulating enzymes from microorganisms in the future.

Reduction-induced interface reconstruction to fabricate MoNi_(4) - based hollow nanorods for hydrazine oxidation assisted energysaving hydrogen production in seawater

Seawater electrolysis could address the water scarcity issue and realize the grid-scale production of carbon-neutral hydrogen,while facing the challenge of high energy consumption and chloride corrosion.Thermodynamically more favorable hydrazine oxidation reaction(HzOR)assisted water electrolysis is efficiency for energy-saving and chlorine-free hydrogen production.Herein,the MoNi alloys supported on MoO_(2) nanorods with enlarged hollow diameter on Ni foam(MoNi@NF)are synthesized,which is constructed by limiting the outward diffusion of Ni via annealing and thermal reduction of NiMoO_(4) nanorods.When coupling HzOR and hydrogen evolution reaction(HER)by employing MoNi@NF as both anode and cathode in two-electrode seawater system,a low cell voltage of 0.54 V is required to achieve 1,000 mA·cm^(−2) and with long-term durability for 100 h to keep above 100 mA·cm^(−2) and nearly 100%Faradaic efficiency.It can save 2.94 W·h to generate per liter H_(2) relative to alkaline seawater electrolysis with 37%lower energy equivalent input.

Detail control strategies for topology optimization in architectural design and development

With the ability to generate forms with high efficiency and elegant geometry,topology optimization has been increasingly used in architectural and structural designs.However,the conventional topology optimization techniques aim at achieving the structurally most efficient solution without any potential for architects or designers to control the design details.This paper introduces three strategies based on Bi-directional Evolutionary Structural Optimization(BESO)method to artificially pre-design the topological optimized structures.These strategies have been successfully applied in the computational morphogenesis of various structures for solving practical design problems.The results demonstrate that the developed methodology can provide the designer with structurally efficient and topologically different solutions according to their proposed designs with multi-filter radii,multi-volume fractions,and multi-weighting coefficients.This work establishes a general approach to integrating objective topology optimization methods with subjective human design preferences,which has great potential for practical applications in architecture and engineering industry.

Ultrafast modulation of valley dynamics in multiple WS_(2)−Ag gratings strong coupling system

Strong light-matter interactions in two-dimensional transition metal dichalcogenides(TMDCs)with robust spin-valley degrees of freedom open up the prospect of valleytronic devices.A thorough understanding on the dynamics of the valley polarizations in the strong coupling regime is urgently required.Here,multiple polarized TMDCs-SPPs hybrid systems were constructed by combining monolayer WS_(2)flakes to linear,circular,and spiral Ag gratings,resulting in linear and circular polarized modula-tion on the coherent hybrid states,respectively.Particularly,valley polaritons can be tailored asymmetrically by chiral strong coupling regime.Furthermore,the dynamics of the polarized polaritons were directly analyzed by transient absorption(TA)measure-ment.Both of the linear and circular polarization difference in the TA spectra can be retained for a remarkable long time,leading to a polarized PL even at room tempera-ture.More importantly,in the chiral strong coupled WS_(2)-spiral Ag grating devices,the mechanism of the asymmetrical valley-polarized PL(p_(σ+)=14.9%and p_(σ-)=10.8%)is proved by the opposite valley polarization dynamics in the circularly polarized TA spectra.The multiple polarization modulation in monolayer TMDCs-SPPs strong coupling devices could provide a viable route toward multiple polarization polaritonic devices.

Bi-channel near-and far-field optical vortex generator based on a single plasmonic metasurface

With the recent development of the metasurface,generating an optical vortex in optical far or near fields is realized in various ways.However,to generate vortices in both the near and far fields simultaneously is still a challenge,although it has great potential in the future compact and versatile photonic system.Here,a bi-channel optical vortex generator in both the near and far fields is proposed and demonstrated within a single metasurface,where the surface plasmon vortex and the far-field optical vortex can be simultancously generated under circularly polarized light.The ability of generating vortices with arbitrary topological charges is experimentally demon-strated,which agrces well with simulations.This approach provides great freedom to integrate different vortex generators in a single device and ofers new opprtunities for integrated optical communications,trapping,and other related fields.

An improved window opening behavior model involving the division of the dummy variable’s interval level:Case study of an office building in Xi’an during summer

Window opening behavior significantly impacts indoor air quality,thermal comfort,and energy consumption.A field measurement was carried out in three typical rooms(a standard office,a meeting room and a smoking office)within an office building.The window state and the physical environment were continuously recorded during the measured periods.Three typical window opening behaviors were found in the measured samples,namely,active,moderate,and passive.The common logistic regression coefficient indicated that solar radiation exhibited the greatest effect on window opening behavior in the smoking office and standard office.Typically,window opening behavior in the meeting room was the most strongly correlated with time of the day,mainly because of the meeting schedule for occupants in the meeting room.This study discussed the dividing principles involved in setting the dummy variable interval level(discretizing continuous variables and dividing them into different intervals),and proposed a method to determine the optimal interval level of each variable.The improved model led to the increase in the prediction accuracy rate of the window being opened by 2.0%and 3.3%according to the comparison with the original model based on dummy variables and the common model based on continuous variables,respectively.This study can provide a reference value for simulating energy consumption in office buildings in the future.