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Effect of Heat Input on the Microstructure and Mechanical Properties of 07MnCrMoVR Weld Joints

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Chinese Journal of Mechanical Engineering 2011年第2期24卷 207-213页

作者： XU Lianghong ZHANG Jun chen yanqing Shougang Research Institute of Technology Beijing 100043 China

As a new type of low cracking suscepbility high strength steel,07MnCrMoVR steel has excellent weldability,with low carbon equivalent and cold cracking susceptibility ***,there are still some problems when this steel is on the outdoor actual welding condition,such as having some extend cold cracking suscepbility and embrittlement of heat affected ***, researching works for the welding of this steel mostly focus on the evaluation the weldability of it,only few works are concentrated in how the heat input affecting the embrittlement of *** goal of this research is to study the effect of heat input on the embrittlement of the heat affected zone so as to get the optimal welding heat input range for *** this paper,38 mm 07MnCrMoVR steel made by Shougang is welded by manual arc welding technology,and the effect of heat input on the microstructure and mechanical properties of weld joints is also investigated by use of optical microscope（OM）,scanning electron microscope（SEM）,mechanical properties testing machines and Viker hardness *** microstructure and fractography observation results and the mechanical properties testing results indicate that the 07MnCrMoVR steel made by Shougang has a wide adaptable range for heat input,and when the heat input is in the range of 15-42 kJ/cm,the toughness of the weld joints is *** the increase of heat input,the impact toughness of weld zone and heat affected zone decrease,whereas the tensile strength of the weld joints does not change at *** microstructure of the weld is acicular ferrite with small amount of proeutectoid ferrite,and with the increase of heat input,the ratio of proeutectoid ferrite and the amount of M-A constituent increase,as well as the grain size and the width of the bainite lath in coarsened grain heat affected zone. Fractography results show that with the increase of heat input,the number of dimples in impact fracture specimens decreases,and the cleavage patterns incre

关键词： 07MnCrMoVR heat input microstructure impact toughness heat affected zone

C/Ti/Cu interfacial reaction in SiCf/Cu composites

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Rare Metals 2011年第4期30卷 396-400页

作者： LUO Xian YANG yanqing WANG chen LOU Juhong XUE Chunling State Key Laboratory of Solidification Processing School of Materials Science Northwestern Polytechnical University Xi＇an 710072 China

Continuous SiC fiber reinforced copper matrix （SiC~/Cu） composites were prepared by fiber coating method, and Ti6A14V interlayer was introduced as an interfacial modification coating to improve the interfacial bonding strength. The interfacial reaction characteristics were investigated by transmission electron microscopy （TEM）. The results show that nearly all the titanium atoms reacted with the carbon coating of SiC fibers to form two layers of TiC. Also, a thin copper layer that is sandwiched between these two layers was detected. No Ti-Cu interfacial reaction product was observed. The formation process of the interfacial reaction along with its mechanism was discussed.

关键词： metallic matrix composite copper interfacial reactions silicon carbide fibers

Forecast of Piezoelectric Properties of Crystalline Materials from First Principle Calculation

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Journal of Rare Earths 2006年第z1期24卷 217-221页

作者： Zheng yanqing chen Jianjun Zhang Tao Xin Jun Shi Erwei Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 201800 China Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 201800 China Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 201800 China Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 201800 China Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 201800 China

Piezo crystals including quartz, quartz-like crystals, known and novel crystals of langasite-type structure were treated with density-functional perturb theory (DFPT) using plane-wave pseudopotentials method, within the local density approximation (LDA) to the exchange-correlation functional. Compared with experimental results, the ab initio calculation results have quantitative or semi-quantitative accuracy. It is shown that first principle calculation opens a door to the search and design of new piezoelectric material. Further application of first principle calculation to forecast the whole piezoelectric properties was also discussed.

关键词： first principle calculation DFPT piezoelectricity crystalline materials

A novel reprocessable chloroprene rubber based on dynamic disulfide metathesis

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International Journal of Smart and Nano Materials 2024年第1期15卷 42-61页

作者： Jianliang Jiang Junxue Zhai yanqing chen Dongqi Zhao Yakai Feng School of Chemical Engineering and Technology Collaborative Innovation Center of Chemical Science and Chemical Engineering(Tianjin)Tianjin UniversityTianjinChina R&D Department of China(Yangzhou) Material Handling Tech-Engineering LtdYangzhouChina Key Laboratory of Rubber Plastics of Ministry of Education/Shandong Province (QUsT)School of Polymer Science&EngineeringQingdao University of Science&TechnologyQingdaoChina R&D Department of Tianjin Joaboa Technology Co.Ltd TianjinP.R.China Frontiers Science Center for Synthetic Biology Tianjin UniversityTianjinChina Key Laboratory of Systems Bioengineering(Ministry of Education) Tianjin UniversityTianjinChina

For sustainable application of chloroprene rubber(CR),a new technology is developed by the vulcanization of CR using 2,2'-dithiodipyridine(DPD)as a cross-linking agent with the repro-cessing performance owing to disulfde *** DPD was incorporated into CR vulcanization,the Menschutkin reac-tion between allyl chloride group and pyridine group occurred with a maximum exothermic peak at 184°*** number of effective cross-linking bond at o.5 phr DPD vulcanizate was higher than that at high DPD *** vulcanizate showed high tensile strength(11.12 MPa)and elongation at break(1253±120%)owing to the exchangeable disulfide bond in the *** the catalysis of triphenylphosphine,the metathesis of disulfide compound was improved obviously,which endowed CR/DPD vulcanizates with good recyclability *** cross-linkage maintains its stability at low temperature,thus ensuring the mechanical stability of CR/DPD vulcanizate under the ambient *** and reprocessing of CR/DPD vulcanizate can be conducted with common industrial rubber processing *** reprocessable chloroprene rubber could have potential appli-cation in CR industry,also serve to significantly improve envir-onmental sustainability.

关键词： Chloroprene rubber reprocessable Menschutkin reaction disulfide

Risk factors of distal segment aortic enlargement after complicated type B aortic dissection

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Journal of Interventional Medicine 2019年第4期2卷 154-159页

作者： Yu Shen Simeng Zhang Guanglang Zhu yanqing chen Zheng chen Zaiping Jing Qingsheng Lu Department of Vascular Surgery Changhai HospitalSecond Military Medical University17 Building168 Changhai RoadShanghaiChina Department of Congenital Heart Disease Fuwai HospitalNational Center of Cardiovascular DiseaseChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina

Objectives:Distal segment aortic enlargement(DSAE)is a common complication that influences the long-term prognosis of type B aortic dissection(TBAD)after thoracic endovascular aortic repair(TEVAR).In this study,a multivariate analysis was performed to find potential factors predictive of ***:A single-center retrospective study was performed from 1999 to *** in the study were complicated TBAD patients who underwent TEVAR with uncovered residual *** on the diameter of the distal segment of the uncovered aorta,we assigned patients to an enlargement group and a non-enlargement *** extracted from the medical records included demographic and clinical characteristics and followup computed tomography angiography *** primary endpoints were the all-cause mortality and the presumably aortic-related events that required reintervention during the follow-up ***:For the 333 patients,all-cause mortality was 38(11.41%),and 76(22.82%)patients underwent reintervention.A total of 70(21.02%)patients experienced DSAE,among them were 2 patients who died of aortic rupture and 58 patients who accepted *** analysis reviewed independent risk factors of postoperative DSAE,including current smoking,the residual length of the patent false lumen,the postoperative number of dissection tears in the thoracic aorta and type III aortic arch;as well as protective factors,including the application of a restrictive bare stent(RBS),the length of covered stent in the descending thoracic aorta,and the distance from the residual first tear to the left subclavian artery(LSA).Conclusion:DSAE after TEVAR for patients with a complicated TBAD can be influenced by their current smoking habit,the residual length of patent false lumen,the postoperative number of dissection tears in the thoracic aorta and the aortic arch ***,RBS usage,the length of the covered stent in the descending thoracic aorta and the distance from the residual

关键词： Type B aortic dissection Thoracic endovascular aortic repair Distal segment aortic enlargement Risk factor

The Effect of General Anesthesia Combined with Epidural Anesthesia and PCEA on the Early Postoperative Cognitive Function in Elderly Patients

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The Effect of General Anesthesia Combined with Epidural Anes...

Resilient water quality management: Insights from Japan's environmental quality standards for conserving aquatic life framework

中国中西医结合麻醉学会[CSIA]年会暨第二届全国中西医结合麻醉学术研讨会、江苏省中西医结合学会麻醉专业委员会成立大会

作者： Yu chen yanqing chen Department of Anesthesiology Fujian Provincial Hospital

Background:Postoperative cognitive dysfunction(POCD) is a common neurological complication among the elderly after major *** are marked by deficits of cognitive and memory,comprise a wide range of disorders from neurocognitive,and will resulting in significant long-term morbidity and an overall reduced quality of *** yet,the etiology of POCD is still unclearly,an association between POCD and the anesthetic methods has been *** this study,we assessed if general anesthesia combined with epidural anesthesia + PCIA can reduce the incidence of POCD among the elderly patients that aged over 65 who underwent open radical gastrectomy(ORG).Methods:90 ASA Ⅰgrade elderly patients that aged over 65 who underwent ORG from March 2014 to January 2015 were recruited in the *** to the table of random number,the patients were into three groups:individual general anesthesia + PCIA(Group A),general anesthesia combined with epidural anesthesia + PCIA(Group B) and general anesthesia combined with epidural anesthesia + PCEA(Group C).0.375%ropivacaine were administered epidural in Group B and Group *** function was assessed1 d before operation and on the 6 h,12 h,2d,3d and 5 d after operation,by the Mini-Mental State Examination test(MMSE).HR and MAP were recorded during the different peri-operative periods,i.e.10 min before induction of anesthesia(TO),1 h after skin incision(T1),1 min after abdominal closure(T2),and the moment of extubation(T3).Blood samples were collected from the central venous to detect the concentrations of serum protein S-100 P > NSE by ELISA before induction and 24 h ***:There were no significant differences in age,sex,ASA grade,BMI,operation duration and pre-operative cognitive function among three *** of POCD:at 6 h and 12 h after operation,Group C was lower than Group A and Group *** 2 d postoperation,Group C was lower than Group *** 3d and 5 d postoperation,Group B and Group C were lower

关键词： Epidural block Epidural analgesia Elderly patients Postoperative cognitive function

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Environmental Science and Ecotechnology 2024年第6期22卷 93-108页

作者： Zihan Xu Ying Wang Li Xie Di Shi Jia He yanqing chen chenglian Feng John P.Giesy Kenneth M.Y.Leung Fengchang Wu College of Water Sciences Beijing Normal UniversityBeijing100875China State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental SciencesBeijing100012China School of Materials Science and Engineering Beihang UniversityBeijing100191China Department of Civil Engineering Nagoya Institute of Technology(Nitech)Nagoya4668555Japan Research&Development Affairs Office Tsinghua UniversityBeijing100084China Department of Veterinary Biomedical Sciences and Toxicology Centre University of SaskatchewanSaskatoonSaskatchewanS7N 5B3Canada Department of Integrative Biology and Center for Integrative Toxicology Michigan State UniversityEast LansingMI48895USA Department of Environmental Sciences Baylor UniversityWacoTX76798-7266USA State Key Laboratory of Marine Pollution and Department of Chemistry City University of Hong KongHong Kong999077China

Currently,chemicals and waste are recognized as key drivers of habitat degradation and biodiversity loss in aquatic *** ensure vibrant habitats for aquatic species and maintain a sustainable aquatic food supply system,Japan promulgated its Environmental Quality Standards for the Conservation of Aquatic Life(EQS-CAL),based on its own aquatic life water quality criteria(ALWQC)derivation method and application *** we overview Japan's EQS-CAL framework and highlight their best practices by examining the framework systems and related *** experiences from Japan's EQS-CAL system include:(1)Classifying six types of aquatic organisms according to their adaptability to habitat status;(2)Using a risk-based chemical screening system for three groups of chemical pollutants;(3)Recommending a five-step method for determining ALWQC values based on the most sensitive life stage of the most sensitive species;(4)Applying site-specific implementation mechanisms through a series of Plan-Do-Check-Act *** paper offers scientific references for other jurisdictions,aiding in the development of more resilient ALWQC systems that can maintain healthy environments for aquatic life and potentially mitigate ongoing threats to human societies and global aquatic biodiversity.

关键词： Aquatic life water quality criteria Chemicals Framework Resilient systems Species adaptability

Intranasal dexmedetomidine premedication reduces the MACLMA of sevoflurane and emergence delirium in children:a prospective,randomized,double-blind,placebo-controlled trial

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Intranasal dexmedetomidine premedication reduces the MACLMA ...

Transcutaneous electrical acupoint stimulation alleviates remifentanil-induced hyperalgesia in patients undergoing thyroidectomy:a randomized controlled trial

中国中西医结合麻醉学会[CSIA]年会暨第二届全国中西...

作者： Yusheng Yao Weilan Wu yanqing chen Department of Anesthesiology Fujian Provincial Hospital

Background:Sevoflurane is widely employed for pediatric anesthesia since its beneficial pharmacological ***,the excitatory phenomenon is one of the main disadvantages during the inhalation induction and emergence,particularly in preschool *** there is increasing evidence to support the use of dexmedetomidine as a preanaesthetic medication in children,

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Transcutaneous electrical acupoint stimulation alleviates re...