Tuning electronic structure of RuO_(2)by single atom Zn and oxygen vacancies to boost oxygen evolution reaction in acidic medium

The poor stability of RuO_(2)electrocatalysts has been the primary obstacles for their practical application in polymer electrolyte membrane electrolyzers.To dramatically enhance the durability of RuO_(2)to construct activity-stability trade-off model is full of significance but challenging.Herein,a single atom Zn stabilized RuO_(2)with enriched oxygen vacancies(SA Zn-RuO_(2))is developed as a promising alternative to iridium oxide for acidic oxygen evolution reaction(OER).Compared with commercial RuO_(2),the enhanced Ru–O bond strength of SA Zn-RuO_(2)by forming Zn-O-Ru local structure motif is favorable to stabilize surface Ru,while the electrons transferred from Zn single atoms to adjacent Ru atoms protects the Ru active sites from overoxidation.Simultaneously,the optimized surrounding electronic structure of Ru sites in SA ZnRuO_(2)decreases the adsorption energies of OER intermediates to reduce the reaction barrier.As a result,the representative SA Zn-RuO_(2)exhibits a low overpotential of 210 mV to achieve 10 mA cm^(-2)and a greatly enhanced durability than commercial RuO_(2).This work provides a promising dual-engineering strategy by coupling single atom doping and vacancy for the tradeoff of high activity and catalytic stability toward acidic OER.

Analysis and Innovative Strategies of Tax Preferential Policies to Promote the Sustainable Development of Small-Scale Individual Businesses

This study conducted an in-depth analysis of the current tax preferential policies for small-scale individual businesses and compared them with similar policies both domestically and internationally,aiming to reveal the advantages and disadvantages of the current system.After examining the impact of these tax preferential policies on the economic status of individual business owners and the broader social economy,this article proposes a set of innovative tax preferential strategies based on theoretical foundations.By developing these innovative strategies and clarifying their implementation paths,the aim is to promote the sustainable and healthy development of small-scale individual businesses,thereby fostering comprehensive socio-economic progress.The conclusion of this study not only summarizes policy recommendations with practical significance but also provides theoretical support for the optimization and innovation of future related systems.

Effects of Root Cutting on Morphological Characteristics and Endogenous Hormone Levels of Quercus variabilis Seedlings

The objective of this study was to investigate the effects of root cutting stress on the dynamic changes of endogenous hormone content and growth characteristics of Quercus variabilis roots,and to explore the physiological role of endogenous hormones in regulating root-crown interactions in the short term.The morphological characteristics and endogenous hormone contents of normal roots(no root cutting,CK)and cut roots(cut by 1/3 of the length of the main root,RP)were determined by liquid chromatography,which was combined with mass spectrometry at different levels of different developmental stages.The results showed that the root growth indexes and root endogenous hormones in the RP group were superior to those in the CK group.Through comprehensive analysis of endogenous hormones,it was found that the crosstalk of IAA,JA,ABA and SA could activate the root growth defense.After the root cutting treatment,the root growth of Quercus variabilis seedlings could compensate for the inhibition of taproot growth by promoting lateral root growth.The growth and development of compensatory lateral roots contribute to the increase the total root length of plants,thus promoting the absorption of water and nutrients.It is speculated that plant hormones may be the key factors affecting their development,but this is not only related to the content of a single hormone,but more importantly,it is the interaction between various hormones.

Numerical and Experimental Study on Ventilation Panel Models in a Subway Passenger Compartment

The internal flow field study of car compartments is an important step in railroad vehicle design and optimization. The flow field profile has a significant impact on the temperature distribution and passenger comfort level. Experimental studies on flow field can yield accurate results but carry a high time and computational cost. In contrast, the numerical simulation method can yield an internal flow field profile in less time than an experimental study. This study aims to improve the computational efficiency of numerical simulation by adapting two simplified models—the porous media model and the porous jump face model—to study the internal flow field of a railroad car compartment. The results provided by both simplified models are compared with the original numerical simulation model and with experimental data. Based on the results, the porous media model has a better agreement with the original model and with the experimental results. The flow field parameters (temperature and velocity) of the porous media model have relatively small numerical errors, with a maximum numerical error of 4.7%. The difference between the numerical results of the original model and those of the porous media model is less than 1%. By replacing the original numerical simulation model with the porous media model, the flow field of subway car compartments can be calculated with a reduction of about 25% in computing resources, while maintaining good accuracy.

伊敏矿区地下水水化学特征及其形成作用分析

煤矿区地下水水化学特征及其形成作用对矿井突水水源识别及水害防治具有重要的意义。本文采集伊敏矿区水样21组,综合利用Piper三线图、同位素、Schoeller图、Gibbs图及离子比例关系分析了地下水化学特征及其控制因素。结果表明,矿区不同类型水样主要阳离子为Na^(+),阴离子主要为HCO_(3)−,平均pH值为7.92,TDS平均值为420.59 mg·L^(−1);大气降水、地表水、第四系水以及Ⅰ含水层水化学类型均为HCO_(3)-Ca型,它们之间联系密切,Ⅱ含水层水化学类型为HCO_(3)-Ca型和HCO_(3)-Na型,Ⅲ含水层水与矿井水水化学类型为HCO_(3)-Na型,且Ⅲ含水层水与矿井水δD和δ^(18)O平均值最接近,矿井水主要来源于Ⅲ含水层补给;伊敏矿区地下水及矿井水主要离子形成作用受岩石风化控制,主要离子来源于钾长石、钠长石、钙长石等硅酸盐矿物的溶解,并受到Ca^(2+)、Mg^(2+)、K^(+)、Na^(+)阳离子交换作用的影响.

High-precision geochronology of the Early Cretaceous Yingcheng Formation and its stratigraphic implications for Songliao Basin,China

The Songliao Basin in Northeast Asia is the largest and longest-lived rift basin and preserves a nearcontinuous continental succession of the most of the Cretaceous period,providing great material to investigate the adaption of the terrestrial systems to the Cretaceous greenhouse climate and tectonic events.However,the paucity of precise and accurate radioisotopic ages from the Early Cretaceous strata of the Songliao Basin has greatly held back the temporal and causal correlation of the continental records to the global Early Cretaceous records.Three tuff layers intercalated in the Yingcheng Formation have been intercepted by the SK-2 borehole,which offer excellent materials for radioisotopic dating and calibration of the chronostratigraphy of the Lower Cretaceous sequence of Songliao Basin.Moreover,the Yingcheng Formation recorded the largest and the last of the two major volcanic events in Songliao Basin,which also represents a turning point in the basin evolution history of Songliao from syn-rift stage to post-rift stage.Here we report high-precision U–Pb zircon geochronology by the CA-ID-TIMS technique on three tuff samples from the Yingcheng Formation of the SK-2 borehole in the Songliao Basin to construct a greatly improved,absolute age framework for the Yingcheng Formation and provide crucial age constraints for the Songliao Lower Cretaceous Strata.The new CA-ID-TIMS geochronology constrained the Yingcheng Formation at 102.571+0.320/-2.346 Ma to ca.113 Ma,correlating to the Albian Stage.Combined with the previous published Songliao geochronology,the Quantou Formation is constrained to between 96.442+0.475/-0.086 Ma and 91.923+0.475/-0.086 Ma;the Denglouku Formation is constrained to between 102.571+0.320/-2.346 Ma and 96.442+0.475/-0.086 Ma;the age of the Shahezi Formation is estimated at ca.113 Ma to ca.118 Ma,which could extend to ca.125 Ma in some locations in Songliao Basin.The major unconformity between the Yingcheng Formation and the Denglouku Formation,which represents the transition of the basin from syn-rift to post-rift is thus confined to between 102.571+0.320/-2.346 Ma and 96.442+0.475/-0.086 Ma.This is roughly contemporaneous with the change in the direction of the paleo-Pacific plate motion from west-southwest to north or northwest in mid-Cretaceous,suggesting their possible connections.

欧洲学前融合教育生态系统模式:让所有儿童共享美好童年

秉承让所有儿童共享美好童年的价值理念,欧洲特殊及融合教育发展署与欧洲32国的各级教育部门通力合作,于2017年提出了“学前融合教育生态系统模式”。该模式基于生态系统理论的本体论视角,依据“社会—文化”认识取向的早期教育质量观,澄清了高质量学前融合教育的结构、过程与结果维度,是当前欧洲国家规划、改进、监测和评估其学前融合教育体系的基本框架。由于该模式以支持结构系统为基石,致力于形成多元利益主体合力与全过程质量提升机制,同时充分考虑各国的社会文化背景,坚持尊重差异与保护多样性的教育质量观,所以还为这些欧洲国家构建关于学前融合教育的多层次综合治理系统提供了明确的行动纲领。尽管该模式面临着实证证据的有效性、实践推广的复杂性方面的质疑与挑战,但是仍然能够为我们探寻本土化学前融合教育治理系统与质量提升机制提供有益的启发。我们应继续倡导“零拒绝”理念,努力提升处境不利儿童的学前教育权利保障水平;连通多元利益主体,制定本土化学前融合教育质量评估与改进框架;遵循文化适宜的质量观,因地制宜地促进学前融合教育的多元发展。

Association of swallowing problems with frailty in Chinese hospitalized older patients

Objective:To estimate the prevalence of dysphagia and frailty among hospitalized older patients and to analyze the relationship between dysphagia and frailty in these people.Methods:Data were collected on 386 participants aged 65 and older in a general hospital from April to December 2017.Patients were asked to complete a self-designed demographic questionnaire.Frailty and swallowing function assessments were performed using the Fried frailty phenotype and the 30-ml water swallowing test,respectively.Multiple stepwise logistic regression analyses were used to identify the association between frailty and dysphagia.Results:Dysphagia developed in 31.1%of older people,and 24.4%developed frailty.Frailty was statistically significantly related with dysphagia.Dysphagia was more prevalent in frail and pre-frail patients(48.9%and 32.4%,respectively)than those who were non-frail(13.6%).In multivariate analyses,frail(OR,5.420;95%CI,2.684±10.944;P<0.001)and history of choking/coughing while drinking(OR,2.954;95%CI,1.844±4.733;P<0.001)were associated with dysphagia.result.Conclusions:Frailty is associated with dysphagia.More attention should be paid to frailty and dysphagia of the elderly and further studies are needed to evaluate the correlated mechanism and develop targeted nursing interventions.

A Vaccine Based on the Receptor-Binding Domain of the Spike Protein Expressed in Glycoengineered Pichia pastoris Targeting SARS-CoV-2 Stimulates Neutralizing and Protective Antibody Responses

In 2020 and 2021,severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),a novel coronavirus,caused a global pandemic.Vaccines are expected to reduce the pressure of prevention and control,and have become the most effective strategy to solve the pandemic crisis.SARS-CoV-2 infects the host by binding to the cellular receptor angiotensin converting enzyme 2(ACE2)via the receptor-binding domain(RBD)of the surface spike(S)glycoprotein.In this study,a candidate vaccine based on a RBD recombinant subunit was prepared by means of a novel glycoengineered yeast Pichia pastoris expression system with characteristics of glycosylation modification similar to those of mammalian cells.The candidate vaccine effectively stimulated mice to produce high-titer anti-RBD specific antibody.Furthermore,the specific antibody titer and virus-neutralizing antibody(NAb)titer induced by the vaccine were increased significantly by the combination of the double adjuvants Al(OH)_(3) and CpG.Our results showed that the virus-NAb lasted for more than six months in mice.To summarize,we have obtained a SARS-CoV-2 vaccine based on the RBD of the S glycoprotein expressed in glycoengineered Pichia pastoris,which stimulates neutralizing and protective antibody responses.A technical route for fucose-free complex-type N-glycosylation modified recombinant subunit vaccine preparation has been established.

Porous polymer electrolytes for long-cycle stable quasi-solid-state magnesium batteries

The development of applicable electrolytes is the key point for high-performance rechargeable magnesium batteries(RMBs).The use of liquid electrolyte is prone to safety problems caused by liquid electrolyte leakage.Polymer-based gel electrolytes with high ionic conductivity,great flexibility,easy processing,and high safety have been studied by many scholars in recent years.In this work,a novel porous poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)membrane is prepared by a phase inversion method.By immersing porous PVDF-HFP membranes in MgCl2-AlCl3/TEGDME(Tetraethylene glycol dimethyl ether)electrolytes,porous PVDF-HFP based electrolytes(PPEs)are formed.The PPE exhibits a high ionic conductivity(4.72×10^(-4) S cm-1,25℃),a high liquid electrolyte uptake of 162%,as well as a wide voltage window(3.1 V).The galvanostatic cycling test of Mg//Mg symmetric cell with PPE reveals that the reversible magnesium ion(Mg^(2+))plating/stripping occurs at low overpotentials(~0.13 V).Excellent long cycle stability(65.5 mAh g^(-1) over 1700 cycles)is achieved for the quasisolid-state RMB assembled with MoS2/C cathode and Mg anode.Compared with the liquid electrolyte,the PPE could effectively reduce the side reactions and make Mg^(2+)plating/stripping more uniformly on the Mg electrode side.This strategy herein provides a new route to fabricate high-performance RMB through suitable cathode material and polymer electrolyte with excellent performance.

Learning Effectiveness Oriented Hybrid Teaching Mode

In the course of program comprehension and analysis,we have carried out an effectiveness oriented hybrid teaching mode,and carried out the reform of student-centered teaching methods.The teaching content puts forward specific solution cases from the perspective of industrial practice.Latest literatures from top conferences are analyzed and disused in class,so as to track the state art of research and practice.Practical project is assigned to improve students’practice and innovation ability.Teaching,learning and practice are closely integrated.In each link,students are guided to carry out autonomous and inquiry learning to improve their learning effectiveness.Good learning results have been achieved.

The effects of humus moisture content on underground fires in a Larix gmelinii plantation

Underground fires are a smoldering combustion with a slow spread rate, low temperatures and no flame. They can last from days to several months, and can even become overwintering fires. They are difficult to find, leading to considerable damage to the forests. The moisture content of combustible fuels is an important factor in the occurrence and persistence of underground forest fires. The Daxing’an Mountains are a hot spot for underground fires in China. This paper looks at the influence of different moisture contents on underground fire characteristics using simulation combustion experiments in the laboratory. The study showed that peak temperature and spread rate fluctuation of humus at different moisture levels increased with humus depth. Peak temperature and spread rate fluctuation of humus at different depths decreased with increased moisture;moisture content and depth of humus had a significant effect on peak temperature and spread rate fluctuation;peak temperature at different depths decreased with increased moisture;the spread rate in upper layers increased with moisture content, while the spread rate in the lower layers decreased with increased moisture content.

Performance Evaluation of a Novel and Effective Water-Soluble Aldehydes as Corrosion Inhibitor for Carbon Steel in Aggressive Hydrochloric Medium

A novel and effective water-soluble aldehydes(β-HA)as corrosion inhibitor was synthesized for N80 steel corro-sion in 15%HCl solution,and the corrosion inhibition performance was evaluated by using weight loss,electro-chemical measurements,scanning electron microscope(SEM),quantum chemical calculation and molecular dynamics simulation(MDS).The results show that synthesizedβ-HA showed excellent corrosion performance compared with MHB and PE for carbon steel in 15%HCl solution compared with MHB and PE,and the inhibi-tion efficiency increased with increasing concentration of the inhibitor.The inhibition efficiency of β-HA at 8 mmol/L reached the maximum value 94.08%.The inhibitor acted as mixed-type inhibitor via blocking both the anodic and cathodic reaction.The adsorption of inhibitors on N80 steel surface obeyed Langmuir adsorption isotherm,and the process contained chemisorption and physisorption.TheΔG ads of β-HA was−28.81 kJ·mol^(-1)der the standard atmospheric pressure.Moreover,the theoretical calculation parameters revealed stronger combination and higher interaction energy for inhibitor β-HA comparing with MHB and PE,further demonstrat-ing the correlation between the theoretical and experimental results.

Multiple rapid-responsive probes for hypochlorite detection based on dioxetane luminophore derivatives

In recent years,various methods for detecting exogenous and endogenous hypochlorite have been studied,considering its essential role as a biomolecule.However,the existing technologies still pose obstacles such as their invasiveness,high costs,and complicated operation.In the current study,we developed a glow-type chemiluminescent probe,hypochlorite chemiluminescence probe(HCCL)-1,based on the scaffold of Schaap's 1,2-dioxetane luminophores.To better explore the physiological and pathological functions of hypochlorite,we modified the luminophore scaffold of HCCL-1 to develop several probes,including HCCL-2,HCCL-3,and HCCL-4,which amplify the response signal of hypochlorite.By comparing the luminescent intensities of the four probes using the IVIS®system,we determined that HCCL-2 with a limit of detection of 0.166 mM has enhanced sensitivity and selectivity for tracking hypochlorite both in vitro and in vivo.

Effect of the liquid temperature on the interaction behavior for single water droplet impacting on the immiscible liquid

The interaction of single water droplet impacting on immiscible liquid surface was focused with the temperature varying from 50℃ to 210℃.The impact behavior is recorded with a high-speed camera running at 2000 frames per second.It is found that droplet diameter,oil temperature,andWeber number have important influences on impact behaviors.Three typical phenomena,including penetration,crater-jet,and crater-jet–secondary jet,were observed.Penetration only occurs when the Weber number is below 105.With Weber number increasing to 302,the jet begins to appear.Moreover,to gain deeper physical insight into the crater formation and jet formation,the energy of droplet impingement onto the liquid pool surface was estimated.The oil temperature has a significant effect on the energy conversion efficiency.High temperature is beneficial to improve energy conversion efficiency.

An Empirical Study of Code Clone Clustering Based on Clone Evolution

There are lots of code clones appearing in software,which are similar code fragments with each other. In the past decades,researchers have proposed some state-of-the-art methods to detect clones. The code clones have showing some relationship with the evolution of software. In order to explore relationships between clones and their evolution,we propose a framework to cluster clones with a Fuzzy C-means clustering method.Firstly,we detect all the clones using Ni Cad,and build the clone genealogies for multiple versions software.Secondly,we extract some metrics to describe the clones and their evolution. Finally,we cluster all clone's vectors,which are generated with the different metrics for different proposes. Experimental results on six open source software packages have shown the relationships among the clone life,the number of change times,the clone pattern and et al. can help developers to understand clones.

A Graded and Individualized Teaching and Learning method

Taking the programming course as an example,a comprehensive solution for individualized and precise teaching has been proposed.Firstly,graded teaching strategy is performed.The students are divided into three groups according to their base of learning and the degree of acceptance of knowledge.Designed teaching resources are provided for the teaching mode of low starting points and high landing points.Secondly,a process evaluation method combining online and offline has been proposed.An“evaluation-feedback-improvement”mechanism based on the analysis of students’learning data has been adopted.The practice in Harbin Institute of Technology has shown that the proposed method can not only help students achieve individualized learning goals,but also help teachers achieve precise teaching.

Research and development of prevention and control measures on the transmission of pathogens in compartments of passenger transport

Contagious pathogens like COVID-19 transmitted via respiratory droplets spread effortlessly in the passenger compartments of transport,significantly jeopardizing passengers’safety when taking public transportation.To date,studies on the fundamental theories of airborne droplet transmission and the engineering application of decontamination techniques are insufficient for the prevention and control of pathogens transmitting in the compartments of passenger transport.It is essential to systematically investigate the control approaches to restrain pathogens from transmitting in passenger compartments.Herein,a theoretical framework for calculating the transmission of pathogens in a complex compartment environment was proposed,and experimental platforms that satisfy the Biosafety Level-2 Laboratory safety level for compartment environment simulations were built based on a set of real train cabins.On these bases,numerical investigations on the motion of pathogen-laden droplets were conducted,and decontamination techniques were examined experimentally.Thereby,control measures on the pathogen transmission and pathogen decontamination schemes were proposed.Moreover,highly efficient decontamination devices were developed,and coping strategies for epidemic emergencies were devised.The outcomes provide theoretical and technical support for developing the next generation of transportation and the prevention and control measures cooperatively considering regular and pandemic times.

高速列车过隧道产生压力波的三维特性

本文采用滑移网格法模拟了时速350 km的高速列车通过350 m标准单线隧道,研究了列车前方不同隧道横截面的压力分布,基于等压力曲面描述了压力波的三维特征和传播机理,并提出了一种新式精确的压力传感器布置方案.研究结果表明,隧道横截面距离列车车头越远,平面压力差异越小.受列车车头和隧道横截面形状的影响,压力波不是简单的平面波,而是在传播过程中复杂变化的球面波.以隧道断面的压力差异小于1 Pa来定义平面波,可发现平面波出现在列车前方16.6 m附近.此外,在70-90 m的隧道断面上,隧道壁面测点和建筑限界测点之间的压力峰峰值差异可达13%,因此应将压力传感器布置在附属设施表面而不是隧道壁面.综上所述,本研究对于理解压力波的形成和传播机理以及指导隧道内压力传感器的科学布置具有重要意义.

Recent advances in long-persistent luminescence materials based on host–guest architecture

Organic long-persistent luminescence(LPL)materials,featuring low preparation cost,eco-friendly synthesis,and easy modification of functional groups,have exhibited extensive applications in information encryption,anti-counterfeiting,and biological imaging.Several design strategies including crystallization-inducement,H-aggregation,and host-guest doping to enhance persistent-room-temperature phosphorescence(RTP)effect by precisely controlling intersystem crossing(ISC)constant and suppressing nonradiative decay rates,those are important strategies to enable LPL performance.Among the strategies,researchers have made several efforts to enhance persistent-RTP effect by host-guest interaction,in which the host matrices provide a rigid environment for phosphor guest molecules.The interaction of the luminescent guest molecules with the host matrix can effectively reduce the vibration and rotation of the luminescent molecules,and suppress the non-radiative inactivation,thereby improving the phosphorescence quantum yield.This review aims to summarize several design strategies of pure organic LPL materials based on persistent-RTP effect through host-guest interaction,and describe some applications of pure organic LPL materials in different fields.