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柠檬酸三钾的重金属测定方法改进

广州化工 2024年第7期52卷 139-140,146页

作者：徐佳璇唐燕华林楚卿广东光华科技股份有限公司广东汕头515061

原部颁暂行标准HGB 3292-60《化学试剂柠檬酸钾》中重金属的测定用的是“硫化氢法”,此法操作比较繁琐,前期处理需要加入太多试剂处理,容易引起二次污染,检验时间周期太长。现对柠檬酸三钾中重金属的测定方法进行改进,由原来的“硫化氢... 详细信息

原部颁暂行标准HGB 3292-60《化学试剂柠檬酸钾》中重金属的测定用的是“硫化氢法”,此法操作比较繁琐,前期处理需要加入太多试剂处理,容易引起二次污染,检验时间周期太长。现对柠檬酸三钾中重金属的测定方法进行改进,由原来的“硫化氢法”改为“硫代乙酰胺法”。经过多次实验,验证了用“硫代乙酰胺法”比“硫化氢法”更准更快,由原来的当天不能得出结果到现在只需约10 min即可得到结论,提高了工作效率,更好的为生产把握质量关。

关键词：柠檬酸三钾重金属饱和硫化氢法硫代乙酰胺法

Nuclear charge radius predictions by kernel ridge regression with odd-even effects

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Nuclear Science and Techniques 2024年第2期35卷 94-102页

作者： Lu tang Zhen-hua Zhang Mathematics and Physics Department North China Electric Power UniversityBeijing 102206China Hebei Key Laboratory of Physics and Energy Technology North China Electric Power UniversityBaoding 071000China

The extended kernel ridge regression(EKRR)method with odd-even effects was adopted to improve the description of the nuclear charge radius using five commonly used nuclear *** are:(i)the isospin-dependent A^(1∕3) formula,(ii)relativistic continuum Hartree-Bogoliubov(RCHB)theory,(iii)Hartree-Fock-Bogoliubov(HFB)model HFB25,(iv)the Weizsacker-Skyrme(WS)model WS*,and(v)HFB25**** the last two models,the charge radii were calculated using a five-parameter formula with the nuclear shell corrections and deformations obtained from the WS and HFB25 models,*** each model,the resultant root-mean-square deviation for the 1014 nuclei with proton number Z≥8 can be significantly reduced to 0.009-0.013 fm after considering the modification with the EKRR *** best among them was the RCHB model,with a root-mean-square deviation of 0.0092 *** extrapolation abilities of the KRR and EKRR methods for the neutron-rich region were examined,and it was found that after considering the odd-even effects,the extrapolation power was improved compared with that of the original KRR *** strong odd-even staggering of nuclear charge radii of Ca and Cu isotopes and the abrupt kinks across the neutron N=126 and 82 shell closures were also calculated and could be reproduced quite well by calculations using the EKRR method.

关键词： Nuclear charge radius Machine learning Kernel ridge regression method

Model-driven path planning for robotic plasma cutting of branch pipe with single Y-groove based on pipe-rotating scheme

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Advances in Manufacturing 2024年第1期12卷 94-107页

作者： yan Liu Qiu tang Xin-Cheng Tian School of Control Science and Engineering Shandong UniversityJinan250061People’s Republic of China Engineering Research Center of Intelligent Unmanned System Ministry of EducationJinan250061People’s Republic of China School of Mechanical and Electronic Engineering Shandong Jianzhu UniversityJinan250101People’s Republic of China

The automatic cutting of intersecting pipes is a challenging task in *** improved automation and accuracy,this paper proposes a model-driven path planning approach for the robotic plasma cutting of a branch pipe with a single ***,it summarizes the intersection forms and introduces a dual-pipe intersection *** on this model,the moving three-plane structure(a description unit of the geometric characteristics of the intersecting curve)is constructed,and a geometric model of the branch pipe with a single Y-groove is ***,a novel mathematical model for plasma radius and taper compensation is ***,the compensation model and groove model are integrated by establishing movable ***,to prevent collisions between the plasma torch and workpiece,the torch height is planned and a branch pipe-rotating scheme is *** the established models and moving frames,the planned path description of cutting robot is provided in this novel *** accuracy of the proposed method is verified by simulations and robotic cutting experiments.

关键词： Automatic groove cutting of intersecting pipes Model-driven robot path planning Plasma beam radius and taper compensation

Remote postconditioning induced by brief pulmonary ischemia and reperfusion attenuates myocardial reperfusion injury in rabbits

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Chinese Medical Journal 2011年第11期124卷 1683-1688页

作者： tang yan-hua XU Jian-jun LI Ju-xiang CHENG Xiao-shu Department of Cardiothoracic Surgery Department of Cardiology Second Affiliated Hospital of Nanchang University Nanchang Jiangxi330006 China

Background The lung is one of the most important organs that are sensitive to ischemia. We hypothesized that remote postconditioning （RPostC） induced by brief occlusion and reperfusion of the pulmonary artery could attenuate myocardial reperfusion injury. Methods Thirty rabbits were randomized into three groups. Group ischemia-reperfusion （IR）（n=10） were anesthetized rabbits subjected to 30-minute occlusion of the left anterior descending coronary artery followed by 180-minute reperfusion.

关键词： remote postconditioning endothelial nitric oxide synthase reperfusion injury

Analyzing topics in social media for improving digital twinning based product development

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Digital Communications and Networks 2024年第2期10卷 273-281页

作者： Wenyi tang Ling Tian Xu Zheng Ke yan School of Computer Science and Engineering University of Electronic Science and Technology of ChinaChengdu611731China

Digital twinning enables manufacturers to create digital representations of physical entities,thus implementing virtual simulations for product *** efforts of digital twinning neglect the decisive consumer feedback in product development stages,failing to cover the gap between physical and digital *** work mines real-world consumer feedbacks through social media topics,which is significant to product *** specifically analyze the prevalent time of a product topic,giving an insight into both consumer attention and the widely-discussed time of a *** primary body of current studies regards the prevalent time prediction as an accompanying task or assumes the existence of a preset ***,these proposed solutions are either biased in focused objectives and underlying patterns or weak in the capability of generalization towards diverse *** this end,this work combines deep learning and survival analysis to predict the prevalent time of *** propose a specialized deep survival model which consists of two *** first module enriches input covariates by incorporating latent features of the time-varying text,and the second module fully captures the temporal pattern of a rumor by a recurrent network ***,a specific loss function different from regular survival models is proposed to achieve a more reasonable *** experiments on real-world datasets demonstrate that our model significantly outperforms the state-of-the-art methods.

关键词： Digital twinning Product development Topic analysis Social media

The Structure Entropy of Social Networks

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Journal of Systems Science & Complexity 2024年第3期37卷 1147-1162页

作者： LI Zhenpeng yan Zhihua yanG Jian tang Xijin School of Electronics and Information Engineering Taizhou UniversityLinhai 317000China Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China Yunnan Key Laboratory of Smart City in Cyberspace Security Yuxi Normal UniversityYuci 653100China University of Chinese Academy of Sciences Beijing 100039China

Micro triadic structure is an important motif and serves the building block of complex *** this paper,the authors define structure entropy for a social network and explain this concept by using the coded triads proposed by Davis and Leinhardt in *** proposed structure entropy serves as a new macro-evolution index to measure the network’s stability at a given *** analysis of real-world network structure entropy discloses rich information on the mechanism that yields given triadic motifs frequency *** paper illustrates the intrinsic link between the micro dyadic/triadic motifs and network structure ***,the authors find that the high proportion of reciprocity and transitivity results in the emergence of hierarchy,order,and cooperation of online social networks.

关键词： Dyadic and triadic motifs network structure entropy reciprocity and transitivity

Identifying the best common factor model via exploratory eactor analysis

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Applied Mathematics(A Journal of Chinese Universities) 2024年第1期39卷 24-33页

作者： HE Bao-hua tang Rui TAGN Qi-yi School of Big Data Fuzhou University of International Studies and TradeFuzhou 350202China School of Mathematics Sun Yat-Sen UniversityGuangzhou 510275China Department of Computer Science University of BathUK Institute of Insect Science Zhejiang UniversityHangzhou 310058China.

Currently,there is no solid criterion for judging the quality of the estimators in factor *** paper presents a new evaluation method for exploratory factor analysis that pinpoints an appropriate number of factors along with the best method for factor *** proposed technique consists of two steps:testing the normality of the residuals from the fitted model via the Shapiro-Wilk test and using an empirical quantified index to judge the quality of the factor *** are presented to demonstrate how the method is implemented and to verify its effectiveness.

关键词： factor analysis Shapiro-Wilk normality residuals

A Reliable Iteration Algorithm for One-Bit Compressive Sensing on the Unit Sphere

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 801-822页

作者： yan-cheng LU Ning BI An-hua WAN School of Mathematics Sun Yat-sen UniversityGuangzhou 510275China

The one-bit compressed sensing problem is of fundamental importance in many areas,such as wireless communication,statistics,and so ***,the optimization of one-bit problem coustrained on the unit sphere lacks an algorithm with rigorous mathematical proof of convergence and *** this paper,an iteration algorithm is established based on difference-of-convex algorithm for the one-bit compressed sensing problem constrained on the unit sphere,with iterating formula■,where C is the convex cone generated by the one-bit measurements andη_(1)>η_(2)>1/*** new algorithm is proved to converge as long as the initial point is on the unit sphere and accords with the measurements,and the convergence to the global minimum point of the l_(1)norm is discussed.

关键词： one-bit compressed sensing difference of convex algorithm iteration algorithm ■1-minimization

(Parallel) kinetic resolution of 3,3-disubstituted indolines via organocatalyzed reactions with azodicarboxylates

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Science China Chemistry 2024年第3期67卷 973-980页

作者： Qianwen Jiang Dekun Zhang Mengyao tang hua Liu Xiaoyu yang School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China

A novel kinetic resolution(KR) method has been developed for 3,3-disubstituted indolines, whose catalytic asymmetric synthesis remains a significant challenge in organic synthesis. The key to the success of this KR protocol lies in the utilization of chiral phosphoric acid-catalyzed triazane formation reaction with azodicarboxylates, which enables the enantioselective synthesis of various substituted indolines bearing C3-quaternary stereocenters with good to high enantioselectivities(with sfactors up to 70). Moreover, an intriguing parallel kinetic resolution(PKR) has been developed by combining triazane formation and dehydrogenation reactions using different azodicarboxylates. Experimental studies have provided insight into the mechanism of this PKR reaction, demonstrating stereoselectivity in both triazane formation and dehydrogenation steps, favoring the opposite enantiomers. The large-scale synthesis and diverse derivatizations of the products, particularly the imine groupcontaining 3H-indoles, demonstrate the value of these(P)KR methods.

关键词： asymmetric organocatalysis kinetic resolution 3 3-disubstituted indolines azodicarboxylate triazanes