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Rhodium(Ⅰ)-Catalyzed Enantioselective C(sp^(3))-H Functionalization via Carbene-Induced Asymmetric Intermolecular C-H Insertion

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Chinese Journal of Chemistry 2021年第7期39卷 1911-1915页

作者： bo Liu ming-Hua Xu Shenzhen Grubbs Institute and Department of Chemistry Guangdong Provincial Key Laboratory of CatalysisSouthern University of Science and Technology1088 Xueyuan BoulevardShenzhenGuangdong518055 China Shanghai Institute of Materia Medica Chinese Academy of Sciences555 Zuchongzhi RoadShanghai201203 China

Main observation and conclusion Transition-metal-catalyzed C-H insertion of metal-carbene represents an excellent and powerful approach for C-H ***,despite remarkable advances in metal-carbene chemistry,transition metal catalysts that are capable of enantioselective intermolecular carbene C-H insertion are mainly constrained to dirhodium(Ⅱ)and iridium(Ⅲ)-based complexes.

关键词： Asymmetric catalysis C-H functionalization carbene C-H insertion Rhodium

UV Photodissociation Dynamics of Nitric Acid： The Hydroxyl Elimination Channel

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Chinese Journal of Chemical Physics 2009年第2期22卷 191-196页

作者： Feng-yan Wang Zhi-chao Chen Yong-wei Zhang Quan Shuai bo Jiang Dong-xu Dai Xiu-yan Wang Xue-ming yang State Key Laboratory of Molecular Reaction Dynamics Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China

Sliced velocity mapping ion imaging technique was employed to investigate the dynamics of the hydroxyl elimination channel in the photodissociaiton of nitric acid in the ultraviolet region. The OH product was detected by （2＋1） resonance enhanced multiphoton ionization via the D^2∑^- electronic state. The total kinetic energy spectra of the OH＋NO2 channel from the photolysis of HONO2 show that both ：NO2（X2A1） and NO2（A2B2） channels are present, suggesting that both 1^1A″ and 2^1A″ excited electronic states of HONO2 are involved in the excitation. The parallel angular distributions suggest that the dissociation of the nitric acid is a fast process in comparison with the rotational period of the HNO3 molecule. The anisotropy parameter β for the hydroxyl elimination channel is found to be dependent on the OH product rotational state as well as the photolysis energy.

关键词： Slice imaging technique Photodissociation dynamics Nitric acid OH radical Resonance enhanced multiphoton ionization

Impact of nodular size on the predictive values of gray-scale,color-Doppler ultrasound,and sonoelastography for assessment of thyroid nodules

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2012年第9期13卷 707-716页

作者： Yu-rong HONG Yu-lian WU Zhi-yan LUO Ning-bo WU Xue-ming LIU Department of Ultrasound the Second Affiliated HospitalSchool of MedicineZhejiang UniversityHangzhou 310009China Department of General Surgery the Second Affiliated HospitalSchool of MedicineZhejiang UniversityHangzhou 310009China)

Objective:To define the roles of gray-scale,color-Doppler ultrasound,and sonoelastography for the assessment of thyroid nodule to determine whether nodule size affects the differential diagnosis of benign and ***:A total of 243 consecutive subjects(214 women,29 men) with 329 thyroid nodules were examined by gray-scale,color-Doppler ultrasound,and sonoelastography in this prospective *** patients underwent surgery and the final diagnosis was obtained from histopathological ***:Three hundred and twenty-nine nodules(208 benign,121 malignant) were divided into small(SNs,5-10 mm,n=137) and large(LNs,>10 mm,n=192) *** were more frequent in malignant LNs than in malignant SNs,but showed no significant difference between benign LNs and ***-circumscribed margins were not significantly different between malignant SNs and LNs,but were less frequent in benign LNs than in benign *** all nodules,marked intranodular vascularity was more frequent in LNs than in *** comparison,shape ratio of anteroposterior to transverse dimensions(A/T) ≥1 was less frequent in LNs than in ***,among all nodules,marked hypoechogenicity and elasticity score of 4-6 showed no significant difference between LNs and ***:The predictive values of microcalcifications,nodular margins,A/T ratio,and marked intranodular vascularity depend on nodule size,but the predictive values of echogenicity and elastography do not.

关键词： Ultrasound Thyroid nodules Sonoelastography Nodule size

Experimental study on dynamic response characteristics of isolated-span transmission lines after ice-shedding

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High Voltage 2023年第1期8卷 196-208页

作者： Guizao Huang bo yan Yujun Guo bo Zhang Guangning Wu School of Electrical Engineering Southwest Jiaotong UniversityChengduChina College of Aerospace Engineering Chongqing UniversityChongqingChina State Grid Henan Electric Power Research Institute ZhengzhouChina

The dynamic response characteristics,including maximum jump height and unbalanced tension,of isolated-span transmission lines after ice-shedding are investigated by means of experiments.A reduced-scale modelling method for ice-shedding from conductor lines is presented and verified with numerical simulations and full-scale test results in the literature.A parameter study on dynamic responses of isolated-span conductors under three ice-shedding scenarios,including whole span ice-shedding,partial ice-shedding and unzipping ice-shedding,is carried out by means of reduced-scale modelling *** effects of these parameters on the maximum jump height at typical positions and unbalanced tension in the tension tower are *** is observed that the partial iceshedding scenario may be the worst situation for electrical insulation clearance rather than the whole span ice-shedding ***,the position of maximum jump height along the span of isolated-span transmission lines after ice-shedding could be at around 2/5 of span length,which is different from the conventional opinion that the position is at the *** results may provide a foundation for the defining of the insulation clearance for an isolated-span transmission line and the structure design of tension tower arms in an iced zone.

关键词： dynamic characteristics insulation

Causal effects of circulating vitamin levels on the risk of heart failure:a Mendelian randomization study

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Journal of Geriatric Cardiology 2023年第3期20卷 195-204页

作者： bo GUAN Xiao-Qiang CHEN yan LIU Hui ZHOU ming-yan yanG Hong-Wei ZHENG Shi-Jun LI Jian CAO Medical School of Chinese PLA General Hospital BeijingChina Department of Cardiology Shanghai General HospitalSchool of MedicineShanghai Jiao Tong UniversityShanghaiChina Xiangya School of Nursing Central South UniversityChangshaHunanChina Department of Cardiology Tangshan Gongren Hospital Affiliated to Hebei Medical UniversityTangshanChina Geriatric Cardiology Department of the Second Medical Center and National Clinical Research Center for Geriatric Diseases Chinese PLA General HospitalBeijingChina

BACKGROUND Observational studies suggest inverse associations between serum vitamin levels and the risk of heart failure(HF). However, the causal effects of vitamins on HF have not been fully elucidated. Here, we conducted a Mendelian randomization(MR) study to investigate the causal associations between genetically determined vitamin levels and *** Genetic instrumental variables for circulating vitamin levels, including vitamins A, B, C, D, and E, which were assessed as either absolute or metabolite levels were obtained from public genome-wide association studies. Summary statistics for single-nucleotide-polymorphisms and HF associations were retrieved from the HERMES Consortium(47,309 cases and 930,014controls) and FinnGen Study(30,098 cases and 229,612 controls). Two-sample MR analyses were implemented to assess the causality between vitamin levels and HF per outcome database, and the results were subsequently combined by *** Our MR study did not find significant associations between genetically determined circulating vitamin levels and HF risk. For absolute vitamin levels, the odds ratio for HF ranged from 0.97(95% confidence interval [CI]: 0.85–1.09, P = 0.41) for vitamin C to 1.05(95% CI: 0.61–1.82, P = 0.85) for vitamin A. For vitamin metabolites, the odds ratio ranged between 0.94(95% CI:0.75–1.19, P = 0.62) for α-tocopherol and 1.11(95% CI: 0.98–1.26, P = 0.09) for γ-*** Evidence from our study does not support the causal effects of circulating vitamin levels on HF. Therefore,there may be no direct beneficial effects of vitamin intake on the prevention of primary HF.

关键词： vitamin prevention absolute

GsMAPK4,a positive regulator of soybean tolerance to salinity stress

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Journal of Integrative Agriculture 2019年第2期18卷 372-380页

作者： QIU You-wen FENG Zhe FU ming-ming YUAN Xiao-han LUO Chao-chao YU yan-bo FENG yan-zhong WEI Qi LI Feng-lan College of Life Science Northeast Agricultural UniversityHarbin 150030P.R.China Heilongjiang Institute of Education Harbin 150030P.R.China Heilongjiang Academy of Agricultural Sciences Harbin 150086P.R.China

Salt stress is one of the major factors affecting plant growth and yield in soybean under saline soil condition. Despite many studies on salinity tolerance of soybean during the past few decades, the detailed signaling pathways and the signaling molecules for salinity tolerance regulation have not been clarified. In this study, a proteomic technology based on two-dimensional gel electrophoresis(2-DE) and mass spectrometry(MS) were used to identify proteins responsible for salinity tolerance in soybean plant. Real-time quantitative PCR(qRT-PCR) and Western blotting(WB) were used to verify the results of 2-DE/MS. Based on the results of 2-DE and MS, we selected glucosyltransferase(GsGT4), 4-coumarate, coenzyme A ligase(Gs4 CL1), mitogen-activated protein kinase 4(GsMAPK4), dehydration responsive element binding protein(GsDREB1), and soybean cold-regulated gene(GsSRC1) in the salinity tolerant soybean variety, and GsMAPK4 for subsequent research. We transformed soybean plants with mitogen-activated-protein kinase 4(GsMAPK4) and screened the resulting transgenics soybean plants using PCR and WB, which confirmed the expression of GsMAPK4 in transgenic soybean. GsMAPK4-overexpressed transgenic plants showed significantly increased tolerance to salt stress, suggesting that GsMAPK4 played a pivotal role in salinity tolerance. Our research will provide new insights for better understanding the salinity tolerance regulation at molecular level.

关键词： soybean salinity tolerance two-dimensional gel electrophoresis GsMAPK4

Effect of B_2O_3 on Melting Temperature of CaO-Based Ladle Refining Slag

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Journal of Iron and Steel Research International 2010年第10期17卷 18-22页

作者： WANG Hong-ming LI Gui-rong LI bo ZHANG Xue-jun yan Yong-qi School of Materials Science and Engineering Jiangsu University Zhenjiang 212013 Jiangsu China Stainless Steel BranCh Baosteel Group Shanghai 200431 China

B2O3 is selected as fluxing agent of CaO-based ladle refining slag to decrease the melting temperature as well as to improve the speed of slag forming and the refining efficiency. The effects of B2O3 on the melting temperature of two series of refining slags including the low basicity slags （the mass ratio of CaO/SiO2 is 3--4） and the high basicity slags （the mass ratio of CaO/SiO2 is 5--8.75） were investigated. The slag melting temperature was meas- ured using the hemisphere method. The results indicate that the fluxing action of B2O3 is better than that of CaF2 and A1203. For the CaO-based refining slag with low basicity, the melting temperature is decreased effectively when B2O3 is used to substitute for equal mass of CaF2, Al2O3 and SiO2, respectively. For the CaO-based refining slag with high basicity, when CaF2 is substituted by B2 03, the melting temperature can be decreased remarkably. Espe- cially, when the mass ratios of CaO/Al2O3 and CaO/SiO2 are in the range of 1.1--4.0 and 5.25--8. 0, respectively, the slag melting temperature is lower than 1 300 ℃. Therefore, the 132 03-containing refining slags with high ratios of CaO/Al2O3 and CaO/SiO2 have ultra low melting temperature.

关键词： fluoride-free slag boron oxide CaO-based refining slag melting temperature

Finite element method for coupled diffusion-deformation theory in polymeric gel based on slip-link model

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Applied Mathematics and Mechanics(English Edition) 2018年第4期39卷 581-596页

作者： Hengdi SU Huixian yan bo JIN School of Aerospace Engineering and Applied Mechanics Tongji University School of Mechanical and Electrical Engineering Sanming University

A polymeric gel is an aggregate of polymers and solvent molecules, which can retain its shape after a large deformation. The deformation behavior of polymeric gels was often described based on the Flory-Rehner free energy function without considering the influence of chain entanglements on the mechanical behavior of gels. In this paper,a new hybrid free energy function for gels is formulated by combining the EdwardsVilgis slip-link model and the Flory-Huggins mixing model to quantify the time-dependent concurrent process of large deformation and mass transport. The finite element method is developed to analyze examples of swelling-induced deformation. Simulation results are compared with available experimental data and show good agreement. The influence of entanglements on the time-dependent deformation behavior of gels is also *** study of large deformation kinetics of polymeric gel is useful for diverse applications.

关键词： polymeric gel finite element method slip-link model large deformation mass transport kinetics

Entropy optimization based filtering for non-Gaussian stochastic systems

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Science China(Information Sciences) 2017年第12期60卷 33-43页

作者： bo TIAN yan WANG Lei GUO School of Automation Science and Electrical Engineering Beihang University National Key Laboratory on Aircraft Control Technology Beihang University

This paper is concerned with the entropy optimization based filter design for a class of multivariate dynamic stochastic systems with simultaneous presence of non-Gaussian process noise and measurement *** filter consists of time update and measurement update two steps, where the selection of the filter gain in the measurement update equation is a key issue to be addressed. Different from the classic Kalman filter theory, entropy rather than variance is employed as the filtering performance criterion due to the non-Gaussian characteristic of the estimation error. Following the establishment of the relationship between the probability density functions of random noises and estimation error, two kinds of entropy based performance indices are provided. On this basis, the corresponding optimal filter gains are obtained respectively by using the gradient optimization technique. Finally, some numerical simulations are provided to demonstrate the effectiveness of the proposed filtering algorithms.

关键词： non-Gaussian systems joint probability density function(JPDF) quadratic information potential relative entropy optimal filtering