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Effect of adhesive on laser-arc hybrid welding of aluminum alloy to high-strength steel joint

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Journal of Iron and Steel Research International 2020年第9期27卷 1099-1107页

作者： Hong-yang Wang Yu-qing Ma li-ming liu Key Laboratory of liaoning Advanced Welding and Joining Technology School of Materials Science and EngineeringDalian University of TechnologyDalian 116024LiaoningChina

Aluminum alloy 6061 and high-strength steel Q460 were joined by laser-arc-adhesive hybrid welding technology successfully.A Cu alloy interlayer was added between Al alloy and high-strength *** effect of the adhesive on laser-arc-adhesive hybrid welding of Al alloy to high-strength steel was *** optical microscope,scanning electron microscope and electron probe micro-analysis were applied to observe the microstructural evolution and phase transition at Al-Fe interface of laser-arc-adhesive hybrid welded *** results showed the maximum tensile shear strength of the joint without adhesive was 256 *** adding adhesive,the maximum tensile shear strength reached 282 *** combination of the mechanical bonding and the metallurgical effect could improve the mechanical *** shape of the joint in Al alloy changed into a canine-like *** was no porosity in welds because the molten pool of Al alloy and the special keyhole phenomenon of laser welding provided a channel for the decomposed gas to escape from fusion zone.

关键词： Laser-arc welding Aluminum alloy High-strength steel Cu interlayer Adhesive

The Monotone Method for Controllability of the Nonlinear Evolution Systems

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Acta Mathematicae Applicatae Sinica 2011年第4期27卷 721-726页

作者： Yue LU Yong li ming-ji liu College of Mathematics Jilin University Changchun 130012 China

In this paper, we study the controllability of the nonlinear evolution systems. We establish the controllability results by using the monotone operator theory. No compactness assumptions are imposed in the main result... 详细信息

关键词： controllability monotone operator nonlinear control systems

Joining mechanism of Mg alloy/steel butt joints with Cu-Zn interlayer by hybrid laser-TIG welding source

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Journal of Iron and Steel Research International 2018年第2期25卷 221-227页

作者： Gang Song Hong-yang Wang Tao-tao li li-ming liu Key Laboratory of liaoning Advanced Welding and JoiningTechnology School of Materials Science and EngineeringDalian University of Technology Dalian 116024 LiaoningChina

Hybrid laser-TIG （tungsten inert gas） welding technology was used to join the Mg to steel with Cu-Zn interlayer. The effect of Al content in Mg alloy on the interface bonding of AZ31BMg/Q235 steel dissimilar butt joints was investigated. For comparison, ZK60 Mg alloy with no Al addition and AZ31 Mg alloy were utilized. The results showed that AZ31/Q235 butt joints with Cu-Zn interlayer, of which the fractures occurred in the Mg weld seam, showed quite sound and reliable interface bonding. The obvious concentration of element Al occurred along the Mg/steel interface. The results indicated that the addition of Cu-Zn interlayer, especially Zn, could significantly decrease the reaction temperature of Fe-Al at the Mg/ steel interface and promote the formation of reaction layer along the interface. The diffusion of Al element on the Mg-Fe interface was increased by the Cu-Zn interlayer. For ZK60 Mg alloy, Mg and Zn approaching the Mg-Fe interface were evaporated. The intense vaporizing could inhibit the direct contact between steel and Mg weld pool, even destroying the possible formation of reaction layer. The intimate interface bonding of AZ31/Q235 butt joints was attributed to the synergistic effect of element AI and Cu.

关键词： Hybrid laser-TIG welding Cu-Zn interlayer Aluminum Magnesium Steel

Efficient synthesis of 4(3H)-quinazolinones using a soluble polymeric support

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Chinese Chemical Letters 2008年第5期19卷 505-508页

作者： Chang Xie Hong Xia li ming Guo liu ming Wu Ding Key Laboratory of Pesticide ＆ Chemical Biology of Ministry of Education Central China Normal University Wuhan 430079 China

4（3H）-Quinazolinones have been synthesized from poly（ethylene glycol）（PEG） supported aza-Wittig reaction. 2-Dialkylamino- 4（3H）-quinazolinones 6 were synthesized efficiently by reaction of secondary amine with PEG-supported carbodiimides 4, which were obtained from aza-Wittig reaction of PEG-supported iminophosphoranes 3 with isocyanates.

关键词： 4(3H)-Quinazolinone Poly(ethylene glycol) supported Aza-Wittig reaction Carbodiimide Iminophosphorane

The Cysteine Pairs in CLV2 are Not Necessary for Sensing the CLV3 Peptide in Shoot and Root Meristems

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Journal of Integrative Plant Biology 2010年第9期52卷 774-781页

作者： Xiufen Song Peng Guo Chen li Chun-ming liu Key Laboratory of Photosynthesis and Environmental Molecular Physiology Institute of Botany Chinese Academy of Sciences Beijing 100093 China

Receptor-like proteins （RLPs） are involved in both plant defense and developmental processes. Previous genetic and biochemical studies show that the leucine-rich repeat （LRR） receptor-like protein CLAVATA2 （CLV2） functions together with CLAVATA1 （CLV1） and CORYNE （CRN） in Arabidopsis to limit the stem cell number in shoot apical meristem, while in root it acts with CRN to trigger a premature differentiation of the stem cells after sensing the exogenously applied peptides of CLV3p, CLE19p or CLE40p. It has been proposed that disulfide bonds might be formed through two cysteine pairs in the extracellular LRR domains of CLV1 and CLV2 to stabilize the receptor complex. Here we tested the hypothesis by replacing these cysteines with alanines and showed that depletions of one or both of the cysteine pairs do not hamper the function of CLV2 in SAM maintenance. In vitro peptide assay also showed that removal of the cysteine pairs did not affect the perception of CLV3 peptides in roots. These observations allow us to conclude that the formation of disulfide bonds is not needed for the function of CLV2.

关键词： CYSTEINE proteinases PEPTIDES PROTEINS ARABIDOPSIS STEM cells

Unbalanced classification method using least squares support vector machine with sparse strategy for steel surface defects with label noise

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Journal of Iron and Steel Research International 2020年第12期27卷 1407-1419页

作者： li-ming liu Mao-xiang Chu Rong-fen Gong Xin-yu Qi School of Electronic and Information Engineering University of Science and Technology LiaoningAnshan 114051LiaoningChina

Least squares support vector machine (LS-SVM) plays an important role in steel surface defects classification because of its high speed. However, the defect samples obtained from the real production line may be noise. LS-SVM suffers from the poor classification performance in the classification stage when there are noise samples. Thus, in the classification stage, it is necessary to design an effective algorithm to process the defects dataset obtained from the real production line. To this end, an adaptive weight function was employed to reduce the adverse effect of noise samples. Moreover, although LSSVM offers fast speed, it still suffers from a high computational complexity if the number of training samples is large. The time for steel surface defects classification should be as short as possible. Therefore, a sparse strategy was adopted to prune the training samples. Finally, since the steel surface defects classification belongs to unbalanced data classification, LSSVM algorithm is not applicable. Hence, the unbalanced data information was introduced to improve the classification performance. Comprehensively considering above-mentioned factors, an improved LS-SVM classification model was proposed, termed as ILS-SVM. Experimental results show that the new algorithm has the advantages of high speed and great anti-noise ability.

关键词： Steel surface defect Least squares support vector machine Anti-noise Sparseness Unbalanced data

v-Fos transformation effector binds with CD2 cytoplasmic tail

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Chinese Science Bulletin 2006年第1期51卷 38-47页

作者： li ming ZHANG Weilun liu Shilian liu Yanxin ZHENG Dexian National Laboratory of Medical Molecular Biology Institute of Basic Medical Sciences Chinese Academy of Medical Sciences & Peking Union Medical College Beijing 100005 China

We previously reported that v-Fos transformation effector (Fte-1) is a novel CD2 binding protein identified by yeast two hybrid system. In the present study, we further characterize the molecular properties and biological activity of the Fte-1. In vitro interaction analysis by an IAsys Resonant Mirror Bio- sensor further demonstrated that Fte-1 interacts with CD2 specifically, and the dissociation constant (Kd) of Fte-1-CD2 is 10?7 mol. The molecular section analysis showed that protein kinase C (PKC) phos- phorylation site at Ser238 of Fte-1, as confirmed by in vitro phosphorylation, is essential for the specific in- teraction with CD2. Jurkat T cells transfected with expression vector encoding for EGFP-Fte-1 fusion protein showed that Fte-1 displays a clustering dis- tribution in the cells. Upon stimulation by CD2 mono- clonal antibody T11, Fte-1 lost the character of clus- tering distribution and translocation to the plasma membrane, which were disrupted by mutation of Fte-1 (Ser238Gly), suggesting that Fte-1 could be co-localized with CD2 on the membrane, and Fte-1 phosphorylation at Ser238 is a crucial factor in CD2-mediated interaction with Fte-1. Suppression of Fte-1 expression by small interference RNA (siRNA) diminished the susceptibility of Jurkat T cells to apoptosis triggered by phorbol 12-myristate 13-ace- tate (PMA) and ionomycin, indicating that the bio- logical function of Fte-1 may be involved in the regu- lation of activation and apoptosis of T cells. These results provide further evidence that Fte-1 is a novel binding protein of CD2, and may function as a down- stream molecule in the CD2-mediated events.

关键词：磷酸化 Fte-1 CD2 结合蛋白 PKC

Stability of the formation interface under the impact of hydraulic fracture propagation in the vicinity of the formation interface

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Petroleum Science 2020年第4期17卷 1101-1118页

作者： Cong Lu Yun-Xiao Lu Jian-Chun Guo li-ming liu State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu 610500China Sinopec Shengli Petroleum Engineering Co. Ltd.Underground Operation CompanyDongying 257077China PetroChina Sichuan-Chongqing Shale Gas Front Command Chengdu 610056China

Unconventional hydrocarbon reservoirs in layered formations,such as tight sandstones and shales,are continually being *** fracturing is a critical technology for the high-efficiency development of hydrocarbon *** the stress field and stability of the formation interface is vital to understanding stress propagation,preferably before the growing hydraulic fracture contacts the formation *** this study,models are developed for computing the stress field of hydraulic fracture propagation near the formation interface,and the stress fields within and at the two sides of the formation interface are *** failure modes of the interface under the impact of hydraulic fracture propagation in its vicinity are identified,and the corresponding failure criteria are *** simulating the magnitude and direction of peak stress at different parameters,the failure mode and stability of the formation interface are *** reveal that when the interface strength is weak,the formation interface fails before the growing hydraulic fracture contacts it,and its stability is significantly related to a variety of factors,including the type of formation interface,rock mechanical properties,far-field stress,structural parameters,distance between the hydraulic fracture and formation interface,and fracturing execution parameters.

关键词： Formation interface Fracture propagation Stress field Failure criterion Stability

Performance verification and comparison of TianLong automatic hypersensitive hepatitis B virus DNA quantification system with Roche CAP/CTM system

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World Journal of Gastroenterology 2017年第37期23卷 6845-6853页

作者： ming li lin Chen li-ming liu Yong-li li Bo-An li Bo li Yuan-li Mao li-Fang Xia Tong Wang Ya-Nan liu Zheng li Tong-Sheng Guo School of Mechanical Engineering Xi'an Jiaotong University Xi'an Tian Long Science and Technology Co. Ltd. Center of Clinical Laboratory Medicine 302 Military Hospital of China Department of Laboratory Medicine Beijing Xiaotangshan Hospital

AIM To investigate and compare the analytical and clinical performance of Tian Long automatic hypersensitive hepatitis B virus(HBV) DNA quantification system and Roche CAP/CTM *** Two hundred blood samples for HBV DNA testing, HBV-DNA negative samples and high-titer HBV-DNA mixture samples were collected and prepared. National standard materials for serum HBV and a worldwide HBV DNA panel were employed for performance verification. The analytical performance, such as limit of detection, limit of quantification, accuracy, precision, reproducibility, linearity, genotype coverage and cross-contamination, was determined using the Tian Long automatic hypersensitive HBV DNA quantification system(TL system). Correlation and Bland-Altman plot analyses were carried out to compare the clinical performance of the TL system assay and the CAP/CTM system. RESULTS The detection limit of the TL system was 10 IU/m L, and its limit of quantification was 30 IU/m L. The differences between the expected and tested concentrations of the national standards were less than ± 0.4 Log10 IU/m L, which showed high accuracy of the system. Results of the precision, reproducibility and linearity tests showed that the multiple test coefficient of variation(CV) of the same sample was less than 5% for 102-106 IU/m L; and for 30-108 IU/m L, the linear correlation coefficient r2 = 0.99. The TL system detected HBV DNA(A-H) genotypes and there was no cross-contamination during the "checkerboard" test. When compared with the CAP/CTM assay, the two assays showed 100% consistency in both negative and positive sample results(15 negative samples and 185 positive samples). No statistical differences between the two assays in the HBV DNA quantification values were observed(P > 0.05). Correlation analysis indicated a significant correlation between the two assays, r2 = 0.9774. The Bland-Altman plot analysis showed that 98.9% of the positive data were within the 95% acceptable range, and the maximum di

关键词： Analytical performance Hepatitis B virus DNA quantification Clinical performance Hepatitis B virus Real-time quantification PCR