Identification of Mulberry Bacterial Blight Caused by Klebsiella oxytoca in Bazhong,Sichuan,China

To provide a scientific basis for controlling mulberry bacterial blight in Bazhong,Sichuan,China(BSC),this study aimed to isolate and purify pathogenic bacteria from diseased branches of mulberry trees in the region and to clarify their taxonomic status using morphological observation,physiological and biochemical detection,molecular-level identification,and the construction of a phylogenetic tree.A total of 218 bacterial strains were isolated from samples of diseased mulberry branches.Of these,7 strains were identified as pathogenic bacteria based on pathogenicity tests conducted in accordance with Koch’s postulates.Preliminary findings from the analysis of the 16S rRNA sequence indicated that the 7 pathogenic bacteria are members of Klebsiella spp.Morphological observation revealed that the pathogenic bacteria were oval-shaped and had capsules but no spores.They could secrete pectinase,cellulase,and protease and were able to utilize D-glucose,D-mannose,D-maltose,and D-Cellobiose.The 7 strains of pathogenic bacteria exhibited the highest homology with Klebsiella oxytoca.This study identifies Klebsiella oxytoca as the causative agent of mulberry bacterial blight in BSC,laying the foundation for the prevention and control of this pathogen and further investigation into its pathogenic mechanism.

多元混合式教学在仪器分析实验课程中的实践

仪器分析实验课程是化学相关专业实践性与应用性极强的核心实验课程之一。在“双一流”建设的大背景下,针对目前仪器分析实验教学存在的问题,从教学模式、教学内容和教学方法三方面进行改革,打造了线上线下相结合,常规实验、虚拟仿真实验和自主创新设计实验相结合,翻转课堂和问题导向学习法相结合的多元混合式教学课程体系。教学实践证明,这种新型的教学课程体系有利于激发学生的学习兴趣与主动性,引导学生内化知识,培养分析和解决问题的高阶思维与综合能力,提高教学效率,优化教学效果。

授人以鱼和渔:仪器分析实验自主设计实验及思政元素融入

为适应现代教育理念及国家对创新型人才的需求,改革传统实验教学模式并激发学生的自主创新意识,在传统仪器分析实验教学基础上探索和构建以学生为主体、以创新能力培养为中心的自主设计实验教学模式。课程在夯实基础和拔高创新方面取得了平衡,同时拓展了课程思政的范畴,如以学生为中心的自主设计实验模式提升了学生学习主动性,课程高阶性、创新性显著提高,授课教师在更多方面以身作则,示范了严谨的科学态度,并倡导了积极的科学探索态度。通过自主设计实验的开展,学生的基础知识、学习兴趣、实验技能、创新能力等都得到了显著提升,建立了有效的仪器分析学习模式。

Solid-state mechanochemistry advancing two dimensional materials for lithium-ion storage applications:A mini review

The vigorous development of two-dimensional(2D)materials brings about numerous opportunities for lithiumion batteries(LIBs)due to their unique 2D layered structure,large specific surface area,outstanding mechanical and flexibility properties,etc.Modern technologies for production of 2D materials include but are not limited to mechanochemical(solid-state/liquid-phase)exfoliation,the solvothermal method and chemical vapor deposition.In this review,strategies leading to the production of 2D materials via solid-state mechanochemistry featuring traditional high energy ball-milling and Sichuan University patented pan-milling are highlighted.The mechanism involving exfoliation,edge selective carbon radical generation of the 2D materials is delineated and this is followed by detailed discussion on representative mechanochemical techniques for tailored and improved lithium-ion storage performance.In the light of the advantages of the solid-state mechanochemical method,there is great promise for the commercialization of 2D materials for the next-generation high performance LIBs.

化学“101计划”基础化学实验课程建设的思考与实践

化学“101计划”基础化学实验课程适用于拔尖学生培养计划2.0基地学校化学类专业低年级学生,是培养化学基础研究创新人才的高阶基础入门实验课程。本课程可以激发学生化学实验的兴趣,具备继续从事化学后续课程学习和化学研究的基本实验素养。通过以合成和测量为载体的单元实验或小综合实验,服务于基础单元操作学习、基础技能训练,或成为合成化学实验和化学测量学实验等课程学习必要的先导内容,为后续实验课程学习打基础。

Study of the geomagnetic field's regional gradients in Chinese continent using three-dimensional surface Spline model

We combined domestic ground-based and satellite magnetic measurements to create a regional three-dimensional surface Spline(3DSS)gradient model of the main geomagnetic field over the Chinese continent.To improve the precision of the model,we considered the data gap between the ground and satellite data.We compared and analyzed the results of the Taylor polynomial,surface Spline,and CHAOS-6(the CHAMP,?rsted and SAC-C model of Earth’s magnetic field)gradient models.Results showed that the gradients in the south-north and east-west directions of the four models were consistent.The 3DSS model was able to express not only gradients at different altitudes,but also average gradients inside the research area.The two Spline models were able to capture more information on gradient anomalies than were the fitted models.Strong local anomalies were observed in northern Xinjiang,Beijing,and the junction area between Jiangsu and Zhejiang,and the total intensity F decreased whereas the altitude increased.The gradient decreased by 21.69%in the south-north direction and increased by 11.78%in the east-west direction.In addition,the altitude gradient turned from negative to positive while the altitude increased.The Spline model and the two fitted models differed mainly in the field sources they expressed and the modeling theory.

Improved algorithms to plan missions for agile earth observation satellites

This study concentrates of the new generation of the agile （AEOS）. AEOS is a key study object on management problems earth observation satellite in many countries because of its many advantages over non-agile satellites. Hence, the mission planning and scheduling of AEOS is a popular research problem. This research investigates AEOS characteristics and establishes a mission planning model based on the working principle and constraints of AEOS as per analysis. To solve the scheduling issue of AEOS, several improved algorithms are developed. Simulation results suggest that these algorithms are effective.

无机化合物的定性分析——第54届国际化学奥林匹克实验试题解析

介绍第54届国际化学奥林匹克的实验试题及两道预备题的设计思路,并对实验试题进行了详细的解析。实验试题与两道预备题相互关联又彼此独立,可以分别用于本科大一学生的无机化学实验以及高中化学奥赛培训,拓宽学生视野,夯实学科基础,对学生的观察能力、归纳总结能力、化学逻辑思维能力和解决问题的能力均能提供很好的训练。

The study of geomagnetic jerk from 2010 to 2021 based on hourly mean data from global geomagnetic observatories

The secular variation in the global geomagnetic field was analyzed in terms of the annual differences in monthly means by using the hourly mean data from 18 foreign(outside China)observatories of the World Data Center(WDC)for Geomagnetism from January 2010 to January 2020 as well as 9 observatories in the Geomagnetic Network of China from January 2015 to April 2021.In addition,according to the correlation of noisy components from the observatories,a covariance matrix was constructed based on residuals between observations and the CHAOS-7.4 model to remove external contamination.Through a comparison before and after denoising,we found that the overall average standard deviations were reduced by 29.97%in China and by 41.4%outside China.Results showed the correlation coefficient between external noise(mainly the magnetosphere ring current)and the Dst index was 0.82,and the correlation coefficient between external noise and the Ring Current(RC)index reached 0.94.A geomagnetic jerk was globally discovered around 2018.0 on the geomagnetic eastward component Y.The jerk timing in China was around 2020.0,and the earliest one was in2018.75,whereas the timing outside China was around 2018.0,and the earliest one was in 2017.67.This 2-year lag may have been caused by the higher electrical conductivity of the deep mantle.After more data were added,this jerk event was found to occur in an orderly manner in the northern hemisphere as the longitude increased and the intensity gradually increased as well.The variations in location of the jerk center were analyzed according to the CHAOS-7.4 model.Results revealed six extreme points distributed nearby the equator.The strongest was near the equator,at 170°E,and the strength gradually decreased as it extended to the northern and southern hemispheres.Another extreme point with the opposite sign was located at the equator,at 20°W,in the south-central part of the Atlantic,and the strength gradually decreased as it extended into Europe.The covariance matrix method can be used to analyze data from the Macao Science Satellite-1 mission in the future,and this method is expected to play a positive role in modeling and separating the large-scale external field.

南开大学化学一流专业建设的探索与实践

经过多年的探索与实践,南开化学在一流专业建设中已形成鲜明的专业特色,本文从特色化人才培养模式、科研创新能力培养、课堂教学质量督导等方面介绍南开化学一流专业建设的举措及成效。

玻纤含量对玻纤增强聚碳酸酯微结构成型及力学性能的影响

取不同玻纤含量的玻纤增强聚碳酸酯原料,通过注射成型得到拉伸样条,测试力学性能分析玻纤含量对复合材料力学性能的影响。通过扫描电镜观测样条断面的微观形貌,通过流变实验分析玻纤含量对材料剪切黏度的影响规律。结果表明,对比纯PC和20%玻纤含量的复合材料,其拉伸强度和弯曲强度均随着玻纤含量的增大而增大,增大幅度分别为75%和40%。而冲击强度随玻纤含量增大呈现先减小后增大的趋势,转折点在玻纤含量接近10%。同时玻纤的加入将使复合材料的黏度增大,并且表观黏度随着剪切应力的增大而减小,在剪切应力接近8000 Pa时表观黏度急剧下降,最终趋于稳定。制得一种LED高帽檐面罩微结构塑件以研究不同玻纤含量对微结构塑件成型的影响。对于此类微结构塑件,微通道的宽度随玻纤含量增大而减小,玻纤含量在10%左右时微结构成型性及综合力学性能最佳。

联二炔囊泡的光致聚合、热致变色及应用

物理化学实验为各大高校本科化学教学的主干实验课程之一。虽然各高校的物理化学实验内容已十分丰富,但仍然缺乏将不同章节知识点融会贯通以及与学科前沿密切联系的综合型实验内容。我们根据南开大学郭东升教授课题组发表的一篇有关联二炔程序性响应检测胆碱酯酶的工作设计了“联二炔囊泡的光致聚合、热致变色及应用”的物理化学实验,涉及到联二炔缔合胶体的制备、联二炔的紫外光致聚合反应和聚联二炔的热致变色,进而显示其在防伪领域的潜在应用价值。希望通过此实验,使学生对物理化学中的缔合胶体、光化学、热力学、动力学等章节有更深一步的贯通性掌握,并了解自组装、光聚合、变色材料和防伪等相关研究领域的前沿动态。

Effects of virtual environment and self-representations on perception and physical performance in redirected jumping

Background Redirected jumping(RDJ)allows users to explore virtual environments(VEs)naturally by scaling a small real-world jump to a larger virtual jump with virtual camera motion manipulation,thereby addressing the problem of limited physical space in VR applications.Previous RDJ studies have mainly focused on detection threshold estimation.However,the effect VE or self representation(SR)has on the perception or performance of RDJs remains unclear.Methods In this paper,we report experiments to measure the perception(detection thresholds for gains,presence,embodiment,intrinsic motivation,and cybersickness)and physical performance(heart rate intensity,preparation time,and actual jumping distance)of redirected forward jumping under six different combinations of VE(low and high visual richness)and SRs(invisible,shoes,and human-like).Results Our results indicated that the detection threshold ranges for horizontal translation gains were significantly smaller in the VE with high rather than low visual richness.When different SRs were applied,our results did not suggest significant differences in detection thresholds,but it did report longer actual jumping distances in the invisible body case compared with the other two SRs.In the high visual richness VE,the preparation time for jumping with a human-like avatar was significantly longer than that with other SRs.Finally,some correlations were found between perception and physical performance measures.Conclusions All these findings suggest that both VE and SRs influence users'perception and performance in RDJ and must be considered when designing locomotion techniques.

Length-dependent alignment of large-area semiconducting carbon nanotubes self-assembly on a liquid–liquid interface

Aligned arrays of semiconducting carbon nanotubes(s-CNTs)with high homogenous density and orientation are urgently needed for high-performance carbon-based electronics.Herein,a length-controlled approach using combined technologies was developed to regulate the s-CNT length and reduce the length distribution.The impact of different lengths and length distributions was studied during aligned self-assembly on a liquid–liquid confined interface was investigated.The results show that short s-CNTs with a narrow distribution have the best alignment uniformity over the large scale.The optimized and aligned s-CNT array can reach a density as high as 100 CNTs·μm−1 on a 4-inch wafer.The field-effect transistor(FET)performance of these optimized s-CNT arrays was 64%higher than arrays without length-control.This study clarified that rational control of s-CNTs with desired length and length distribution on the aligned self-assembly process within the liquid–liquid confined interface.The results illustrate a solid foundation for the application of emerging carbon-based electronics.

Elastic Full Waveform Inversion Based on the Trust Region Strategy

In this paper, we investigate the elastic wave full-waveform inversion (FWI) based on the trust region method. The FWI is an optimization problem of minimizing the misfit between the observed data and simulated data. Usually, the line search method is used to update the model parameters iteratively. The line search method generates a search direction first and then finds a suitable step length along the direction. In the trust region method, it defines a trial step length within a certain neighborhood of the current iterate point and then solves a trust region subproblem. The theoretical methods for the trust region FWI with the Newton type method are described. The algorithms for the truncated Newton method with the line search strategy and for the Gauss-Newton method with the trust region strategy are presented. Numerical computations of FWI for the Marmousi model by the L-BFGS method, the Gauss-Newton method and the truncated Newton method are completed. The comparisons between the line search strategy and the trust region strategy are given and show that the trust region method is more efficient than the line search method and both the Gauss-Newton and truncated Newton methods are more accurate than the L-BFGS method.

“糖心”共病管理:从指南和共识看糖尿病患者的心血管一级预防和二级预防策略

我国糖尿病患者数量居全球首位,心血管疾病是造成我国2型糖尿病患者死亡的主要原因,而慢性病是导致我国心血管疾病患者死亡的风险之一。《中国心血管病一级预防指南》和《糖尿病患者合并心血管疾病诊治专家共识》为我国糖尿病和心脏病(简称"糖心")共病患者的临床诊治规范化提供了参考。笔者基于上述指南和共识,对糖尿病患者的心血管一级预防和二级预防策略,即"糖心"共病管理进行阐述,在"糖心"共病流行病学的基础上,对糖尿病合并心血管病的机制和相互影响、防治、多重干预和综合管理进行总结,为此类患者的临床诊治规范化提供思路。

Online Healthcare Community Interaction Dynamics

With the increasing dilemma of the rapid global demand for healthcare services(often in the presence of limited resources),how to creatively allocate and use healthcare resources across a widespread population has become a salient issue.Online healthcare communities(OHCs)are regarded as a potential ICT-based partial solution.In contrast to traditional healthcare,online doctor-patient interaction is unlimited in terms of time and space limitations while an OHC is exposed to the whole community.These characteristics are key to achieving synergistic doctor-patient interaction and community development in the longer term.In order to explore the nature of doctor-patient interaction dynamics in an OHC,we systematically investigate doctor-patient interaction dynamics from the dual perspectives of doctor and patient.Our doctor-patient interaction dual-cycle model has been built based on six doctor-patient interaction processes(i.e.,searching,choosing,knowledge sharing,providing,receiving and balancing).According to our dual-cycle model,four key managerial issues in OHC(information asymmetry,incentive mechanisms,service delivery processes and interaction mechanisms)have been identified as examples.Discussion and directions for future research,with challenges as well as opportunities,have been elaborated.A broad view with fruitful research potential is ensured and new theories and methods ultimately provide implications for effectively and efficiently allocating scarce healthcare resources to a broader population.

Computational Methods for Single-cell Multi-omics Integration and Alignment

Recently developed technologies to generate single-cell genomic data have made a revolutionary impact in the field of biology.Multi-omics assays offer even greater opportunities to understand cellular states and biological processes.The problem of integrating different omics data with very different dimensionality and statistical properties remains,however,quite challenging.A growing body of computational tools is being developed for this task,leveraging ideas ranging from machine translation to the theory of networks,and represents another frontier on the interface of biology and data science.Our goal in this review is to provide a comprehensive,up-to-date survey of computational techniques for the integration of single-cell multi-omics data,while making the concepts behind each algorithm approachable to a non-expert audience.

Integrated optimization of multiproduct multiperiod transportation and inventory under a carbon cap constraint for online retailers

This study aims to solve the problem of multiproduct multiperiod integrated transportation and inventory optimization for online retailers.A carbon cap constraint and multitype of capacitated trucks are simultaneously incorporated into the proposed mixed-integer program.A simulated annealing(SA)algorithm is designed.CPLEX 12.9.0 is used to solve the submodel obtained from the neighbourhood search and is also used to get the optimal solutions for instances.Experimental results show that the simulated annealing algorithm can find satisfactory solutions within a reasonable time.When the problem size increases,the growth of the computational time of the SA algorithm is significantly smaller than that of the CPLEX.A sensitivity analysis for the carbon cap is also conducted.The results indicate that if the carbon cap is gradually tightened,the total cost increases first with a gentle slope,and then with a remarkable slope,same as for the total number of trucks used;the total carbon emissions first decrease with a gentle slope,and then decline with a significant slope.When the carbon cap is strict,only a few different types of trucks will be considered.The percentage changes of the total cost increase and the total carbon emission reduction are also compared.When the allowed carbon emissions are gradually reduced,situation of a higher amount of carbon emission reduction and a lower amount of cost increase can be achieved.Additionally,using multiple types of trucks in the integrated optimization of transportation and inventory decisions can achieve greater cost savings with lower increments of carbon emission.

Big data driven management and decision sciences:A NSFC grand research plan

In the age of big data,the real world can be reflected by or is increasingly composed of data,giving rise to the emerging digital economy where data become strategic assets and basic elements for industrial productions and social activities.In recent years,decision making for organizations as well as for individuals is more and more data-centric and analytics-based,which has attracted great attention of academia and practitioners to big data research and applications including nationwide initiatives in China and the globe.In this context,an important research initiative on big data was launched by the National Natural Science Foundation of China(NSFC)in late 2015 in the form of Grand Research Plan(in brief,the Plan),which is an 8-year joint effort of NSFC’s disciplinary departments(i.e.,of Management Sciences,Information Sciences,Mathematical&Physical Sciences,and Health Sciences).The main ideas and progress of the Plan are highlighted as follows.