配合物[Ni(Me_(3)en)(acac)]BPh_(4)合成、分析实验实施结果与讨论——第10届全国大学生化学实验邀请赛无机及分析化学实验试题部分内容实施结果与讨论

介绍南京大学为第10届全国大学生化学实验邀请赛设计的无机及分析化学实验试题,即“配合物[Ni(Me_(3)en)(acac)]BPh_(4)的合成及其溶剂/热致变色行为研究”实验中有关合成及组成测定部分实验实施过程、结果及其拓展问题的探讨内容。以所展示的详细直观的合成实验流程为载体,围绕着合成两大目标“质”和“量”,即如何才能得到又“好”又“多”的[Ni(Me_(3)en)(acac)]BPh_(4)配合物的问题为导向,以设问、探讨的方式引导学生认识合成过程中实验条件的控制、实验现象的分析以及中间产物及杂质的分离、分析鉴定等对指导合成的意义,培养学生分析、判断、归纳、总结的能力以及批判性思维能力。

基础化学实验教学的新理念——再议实验教学之本质

最近20年以来,国内高校的本科基础化学实验教学从理念、内容、标准,到组织机构和评价方法,都经历了一系列变化和改革。立足于新的历史机遇和时代,有必要深刻理解和厘清本科阶段基础化学实验教学的本质和角色,既不轻视和简慢其地位、也不夸大和拔高其效用;须还基础实验教学以其本来面目,着重深挖其在传播"第三类知识"(Knowhow)以及培养"元认知"能力当中的不可替代作用,才能在化学实验教学改革大潮中不懈怠、不迷惘。

Development and evaluation of the Directive and Nondirective Support Scale for Patients with Type 2 Diabetes

Objectives:This study aims to develop the Directive and Nondirective Support Scale for Patients with Type 2 Diabetes(DNSS-T2DM)to measure diabetes-specific support and patients’preference as well as evaluate the construct validity and reliability of the DNSS-T2DM.Methods:A cross-sectional study was conducted in Tongzhou District,Beijing,China from July to September 2015.A total of 474 participants who had been diagnosed as type 2 diabetes by physicians and completed the DNSS-T2DM were included.The original 11-item DNSS-T2DM contains five items on nondirective support(Items 1-5)and six items on directive support(Items 6-11).There were two parallel questions for each item with one to measure the preference for support(Preference part)and the other to measure the perception of support in reality(Reality part).The final DNSS-T2DM was determined based on the results of the exploratory factor analysis(EFA).The construct validity of the final DNSS-T2DM was evaluated by the confirmatory factor analysis(CFA).The reliability was evaluated by internal consistency with Cronbach’sαcoefficients.Results:A final 7-item DNSS-T2DM loaded on 2 factors with four items representing nondirective support and three items representing directive support was determined based on the EFA.The CFA indicated a satisfactory construct validity.The internal consistency of the 7-item DNSS-T2DM as well as the nondirective support items was satisfactory with Cronbach’sα≥7.00.70.Conclusions:Our study supported the validity and reliability of the 7-item DNSS-T2DM.Further studies on the application of the DNSS-T2DM in different settings and population are needed.

南疆枸杞木虱发生规律及绿色防控技术研究

随着农业供给侧结构性改革纵深发展,近几年南疆各地枸杞种植面积持续增加,枸杞木虱危害不断加重。枸杞木虱一年发生5代,中后期各种虫态均共存。南疆枸杞木虱3代中期与4代前期叠加,4代末期与5代前中期叠加,形成两次超高峰,引起7月中下旬与9月中下旬两次叶片全部枯死脱落。木虱在南疆全年危害大,繁殖力强,世代重叠严重,发生量大,呈爆发成灾局势,防治不力会造成毁灭性的危害。笔者通过绿色防控与统防统治相融合、科学合理用药、大面积防治等措施减弱木虱迁飞危害,减少化学农药使用量,为零残留、绿色生态枸杞产业发展提供技术保障。

Advances in Research on Drought Resistance in Rice

Rice is the main grain crop in China. With global warming, drought and water shortage have become one of the important factors limiting rice production. Improving the drought resistance of rice can effectively alleviate the loss of rice yield caused by drought. In this paper, the research progress on rice drought resistance and its evaluation methods, mapping of QTLs for drought resistance-related traits, and mining for drought resistance genes were reviewed, and molecular breeding for drought resistance in rice was prospected.

Characterization and prediction of tailpipe ammonia emissions from in-use China 5/6 light-duty gasoline vehicles

On-road tailpipe ammonia (NH3) emissions contribute to urban secondary organic aerosol formation and have direct or indirect adverse impacts on the environment and human health. To understand the tailpipe NH3 emission characteristics, we performed comprehensive chassis dynamometer measurements of NH3 emission from two China 5 and two China 6 light-duty gasoline vehicles (LDGVs) equipped with three-way catalytic converters (TWCs). The results showed that the distance-based emission factors (EFs) were 12.72 ± 2.68 and 3.18 ± 1.37 mg/km for China 5 and China 6 LDGVs, respectively. Upgrades in emission standards were associated with a reduction in tailpipe NH3 emission. In addition, high NH3 EFs were observed during the engine warm-up period in cold-start cases owing to the intensive emissions of incomplete combustion products and suitable catalytic temperature in the TWCs. Notably, based on the instantaneous NH3 emission rate, distinct NH3–emitting events were detected under high/extra high velocity or rapid acceleration. Furthermore, NH3 emission rates correlated well with engine speed, vehicle specific power, and modified combustion efficiency, which were more easily accessible. These strong correlations were applied to reproduce NH3 emissions from China 5/6 LDGVs. The predicted NH3 EFs under different dynamometer and real-world cycles agreed well with existing measurement and prediction results, revealing that the NH3 EFs of LDGVs in urban routes were within 8.55–11.62 mg/km. The results presented here substantially contribute to improving the NH3 emission inventory for LDGVs and predicting on-road NH3 emissions in China.

An active equalization strategy for series-connected lithium-ion battery packs based on a dual threshold trigger mechanism

It is well acknowledged to all that an active equalization strategy can overcome the inconsistency of lithium-ion cell's voltage and state of charge(SOC)in series-connected lithium-ion battery(LIB)pack in the electric vehicle application.In this regard,a novel dual threshold trigger mechanism based active equalization strategy(DTTMbased AES)is proposed to overcome the inherent inconsistency of cells and to improve the equalization efficiency for a series-connected LIB pack.First,a modified dual-layer inductor equalization circuit is constructed to make it possible for the energy transfer path optimization.Next,based on the designed dual threshold trigger mechanism provoked by battery voltage and SOC,an active equalization strategy is proposed,each single cell's SOC in the battery packs is estimated using the extended Kalman particle filter algorithm.Besides,on the basis of the modified equalization circuit,the improved particle swarm optimization is adopted to optimize the energy transfer path with aiming to reduce the equalization time.Lastly,the simulation and experimental results are provided to validate the proposed DTTM-based AES.

Compari ng the con figured causal antecedents of exploration and exploitation: a fuzzy set qualitative comparative analysis

Although exploration and exploitation, as a pair of paradoxical organizational outcomes, are generated by different causal conditions, the conjunction of their respective causal antecedents has yet to be fully examined. Combining environmental uncertainty, unit interdependence, entrepreneurial bricolage and firm life cycle stage in a qualitative comparative analysis (QCA), the distinct causal configurations of exploration and exploitation are formalized and compared based on a survey of founders or high-level managers in 63 small firms. Results show that contrasted relationships between entrepreneurial bricolage and unit interdependenee exist in that the two antecedents are partial substitutes in exploration whereas they are complements in exploitation when combined with other conditions. This study provides empirical evidence on the causal configurations of exploration and exploitation and deepens our current understanding of ambidexterity.

Microstructures and dynamic processes within the five-phase system:Regarding COVID-19 as a complex system

The research uses the development of 2019 novel coronavirus disease(COVID-19)in the human body as an example to explore the microstructures and dynamic processes of a concise complex system from the lens of the five-phase system.Based on the structural balance theory and system dynamics,the research finds that Iransitive triads and cyclic triads in the fivephase system are both imbalanced.The integration of these differentiated triads comprises of a balaneed intermediate form in the shape of quadrangular cycles.These cycles serve as microstructures of the five-phase system,due to the inherent balancing feedback mechanism,and support the generation of resultants.The alter nation of quadra ngular cycles drives the spirali ng development of the whole system.By orderly and regular in terweaving of sig ned directed links,the research provides a holistic,process-oriented demonstrati on for the developme nt processes of COVID-19.It clarifies that the esse nee of the five-phase system is phase-tra nsition processes with the quadrangular cycle as carrier and supporter,rather than the static aggregati on of five elements.The research deep ens the understanding of system non linearity by visualizi ng the circular causality and promotes the academic dialogue between the Western process theory and the Chinese inherited notion of the fivephase system.

The dual role of ubiquitin-like protein Urm1 as a protein modifier and sulfur carrier

The ubiquitin-related modifier Urm1 can be covalently conjugated to lysine residues of other proteins,such as yeast Ahp1 and human MOCS3,through a mechanism involving the E1-like protein Uba4(MOCS3 in humans).Similar to ubiquitination,urmylation requires a thioester intermediate and forms isopeptide bonds between Urm1 and its substrates.In addition,the urmylation process can be significantly enhanced by oxidative stress.Recent findings have demonstrated that Urm1 also acts as a sulfur carrier in the thiolation of eukaryotic tRNA via a mechanism that requires the formation of a thiocarboxylated Urm1.This role is very similar to that of prokaryotic sulfur carriers such as MoaD and ThiS.Evidence strongly supports the hypothesis that Urm1 is the molecular fossil in the evolutionary link between prokaryotic sulfur carriers and eukaryotic ubiquitin-like proteins.In the present review,we discuss the dual role of Urm1 in protein and tRNA modification.

Midea＇s Re-adoption of M-form Structure

With a focus on the alignment between business strategies and organization design, this illustrative case study describes and analyzes the evolution and reform of Midea＇s organizational structure when confronting both internal and external changes. As one of China＇s biggest and fastest-growing household appliance enterprises, Midea adopted, discarded and readopted an M-form~ organizational structure within a five-year period from 1997. This case study first investigates the reasons behind Midea＇s reform toward decentralization and the formation of governing rules to balance centralization and decentralization. Different decentralized structures are then contrasted basing on product segments, business streams or even key subsidiaries acting as second-tier group companies. After its trial transformation into an H-form company that holds majority shares in several incorporated subsidiaries, Midea chose to switch to a group company incorporated structure soon after its leadership transition in 2012. Preceding the shortening of the group＇s ownership chain was the construction, refinement, and evolution of its 9＋2＋4 divisional structure. This case study is prepared to provoke discussion and thoughts on the （re）design of a properly decentralized structure suitable for large-sized companies with multiple businesses and the links with external and internal factors.