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Effects of Sub-zero Celsius Treatment and Tempering on the Stability of Retained Austenite in Bearing Steel

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Acta Metallurgica Sinica(English Letters) 2015年第6期28卷 787-792页

作者： Xiao-Hui Lu wei Li Cheng-Lin Wang Hong-Shan Zhao Xue-jun Jin State Key Lab of Metal Matrix Composite School of Materials Science and Engineering Shanghai Jiao Tong University Institute of Advanced Steels and Materials School of Materials Science and Engineering Shanghai Jiao Tong University

In this work, the influence of sub-zero Celsius treatment and tempering on the mechanical and thermal stability of retained austenite in beating steel were assessed by tensile test and DSC. Compared with traditional quenched and tempered treatment, sub-zero Celsius treatment obviously decreases the volume fraction of retained austenite. Moreover, the mechanical stability of retained austenite was enhanced due to the accumulation of compressive stresses in retained austenite after sub-zero Celsius treatment and tempering. Meanwhile, the morphology of retained austenite changed from film-like to blocky with austenitization temperature increasing, and the mechanical stability of film-like retained austenite is higher than that of blocky one. The DSC results showed that the activation energy of retained austenite decomposition slightly increased through sub-zero Celsius treatment and tempering. This result may probably be ascribed to partitioning of carbon during tempering. However, the temperature at which retained austenite starts to decompose is unchanged.

关键词： Bearing steel Sub-zero Celsius treatment Retained austenite Stability

Transumbilical single-port laparoscopic cholecystectomy： a case report

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Chinese Medical Journal 2008年第23期121卷 2463-2464页

作者： GUO wei ZHANG Zhong-tao HAN wei LI Jian-she JIN Lan LIU jun ZHAO Xiao-mu WANG Yu Department of General Surgery Beijing Friendship Hospital Capital Medical University Beijing 100050 China

Recently, scarless surgery has become a widely used surgical technique, which has made considerable progress owing to extensive animal model studies and clinical trials. Here, we report the first case of transumbilica... 详细信息

关键词： laparoscopic cholecystectomy clinical trials mainland China animal model

Design and engineering implementation of non-supplementary fired compressed air energy storage system: TICC-500

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Science China(Technological Sciences) 2015年第4期58卷 600-611页

作者： MEI Sheng wei WANG jun Jie TIAN Fang CHEN Lai jun XUE Xiao Dai LU Qiang ZHOU Yuan ZHOU Xiao Xin State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical EngineeringTsinghua University Key Laboratory of Cryogenics Technical Institute of Physics and Chemistry Chinese Academy of Sciences Department of Power Systems China Electric Power Research Institute

The integration and accommodation of the wind and solar energy pose great challenges on today’s power system operation due to the intermittent nature and volatility of the wind and solar resources.High efficient large-scale electrical energy storage is one of the most effective and economical solutions to those problems.After the comprehensive review of the existing storage technologies,this paper proposes an overall design scheme for the Non-supplementary Fired Compressed Air Energy Storage(NFCAES)system,including system design,modeling and efficiency assessment,as well as protection and control.Especially,the design principles of the multistage regenerative,i.***.heat recovery system which is used to fully recycle and utilize the waste heat from compression are provided,so as the overall system efficiency evaluation method.This paper theoretically ascertains the storage decoupling rules in the potential and internal energy of molecular compressed air and reveals the conversion mechanism of gas,heat,power,electricity and other forms of energy.On this basis,a 500-k W physical simulation system of CAES system(TICC-500,Tsinghua-IPCCAS-CEPRI-CAES)is built,which passed a system-wide 420-k W load power generation test with less pollution and zero carbon emissions.Besides,the multi-form energy conversion of multi-stage regenerative CAES and storage efficiency is verified,especially its incomparable superiority in solving the uncertainty problem in wind and solar power generation.Finally,the propaganda and application scenario of the CAES system in China is introduced.

关键词：储能系统压缩空气设计工程实施电力系统运行太阳能资源热回收系统烧制

Liquid crystal depolarizer based on photoalignment technology

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Photonics Research 2016年第2期4卷 70-73页

作者： Bing-Yan wei Peng Chen Shi-jun Ge Li-Chao Zhang wei Hu Yan-Qing Lu National Laboratory of Solid State Microstructures Collaborative Innovation Center of Advanced Microstructures and College of Engineering and Applied Sciences Nanjing University Thorlabs China

We propose a depolarizer based on the principle of a collection of half-wave plates with randomly distributed optic axes. The design is demonstrated by means of dynamically photopatterning liquid crystal into randomly aligned homogeneous domains. We characterize the liquid crystal depolarizer for 1550 nm and C-band(1520–1610 nm). A degree of polarization of less than 5% is obtained for any linearly polarized light. This study provides a practical candidate for high-performance depolarizers.

关键词： DOP Liquid crystal depolarizer based on photoalignment technology

Conversion therapy and suitable timing for subsequent salvage surgery for initially unresectable hepatocellular carcinoma: What is new?

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World Journal of Clinical Cases 2018年第9期6卷 259-273页

作者： Ze-Feng Zhang Yu-jun Luo Quan Lu Shi-Xue Dai wei-Hong Sha Department of Gastroenterology and Hepatology Guangdong Geriatrics Institute Guangdong General Hospital Guangdong Academy of Medical Sciences

AIM To review the conversion therapy for initially unre-sectable hepatocellular carcinoma(HCC) patients and the suitable timing for subsequent salvage surgery. METHODS A Pub Med search was undertaken from 1987 to 2017 to identify articles using the keywords including "unresectable" "hepatocellular carcinoma", "hepate-ctomy", "conversion therapy", "resection", "salvage surgery" and "downstaging". Additional studies were investigated through a manual search of the references from the articles. The exclusion criteria were duplicates, case reports, case series, videos, contents unrelated to the topic, comments, and editorial essays. The main and widely used conversion therapies and the suitable timing for subsequent salvage surgery were discussed in detail. Two members of our group independently performed the literature search and data extraction. RESULTS Liver volume measurements [future liver remnant(FLR)/total liver volume or residual liver volume/bodyweight ratio] and function tests(scoring systems and liver stiffness) were often performed in order to justify whether patients were suitable candidates for surgery. Successful conversion therapy was usually defined as downstaging the tumor, increasing FLR and providing subsequent salvage surgery, without increasing com-plications, morbidity or mortality. The requirementsfor performing salvage surgery after transcatheter arterial chemoembolization were the achievement of a partial remission in radiology, the disappearance of the portal vein thrombosis, and the lack of extrahepatic metastasis. Patients with a standardized FLR(sF LR) > 20% were good candidates for surgery after portal vein embolization, while other predictive parameters like growth rate, kinetic growth rate were treated as an effective supplementary. There was probably not enough evidence to provide a standard operation time after associating liver partition and portal vein ligation for staged hepatectomy or yttrium-90 microsphere radioembolization. The indications of any combinations of conversion the

关键词： Unresectable Hepatocellular carcinoma Hepatectomy Conversion therapy Salvage surgery Downstaging

Automotive Traction Drive Speed Reducer Efficiency Testing

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Automotive Innovation 2021年第1期4卷 81-92页

作者： wei Wang James M.Durack Michael J.Durack jun Zhang Peng Zhao Automotive Research Institute(Suzhou) Tsinghua UniversityBeijingChina Ultimate Transmissions Pty.Ltd StrathfieldAustralia

The move from internal combustion engine vehicles to electric vehicles is happening rapidly,which demands a stepwise change in priorities for the vehicle design process with rational consideration of emerging technologies.This paper focuses on the efficiency of a particular form of high fixed-ratio(15:1)traction drive speed reducer.This is suitable for use in conjunction with a high-speed electric motor for automotive applications.A general discussion of the characteristics of other fixed-ratio traction drives is provided followed by an analysis of underlying efficiency issues.The paper presents details of the speed reducer prototype called a"Silk Drive"and the vehicle for which it was designed.Data from laboratory testing of the prototype are presented,and an efficiency map for the transmission is developed.The efficiency map and vehicle parameters are used in a simulation to determine the overall transmission efficiency for the world harmonized light vehicles test cycles(WLTC)class 3b drive cycle.The importance of transmission efficiency at low power levels,in specific input speed and torque regions,is demonstrated using a novel method for identifying those speed torque regions that most strongly affect overall efficiency.The method applies to all drivetrain components and pinpoints those regions that need to be the focus in the optimal design of such components.This paper presents evidence that the efficiency of zero-spin,fixed-ratio traction drives is similar to that of conventional gear drives.

关键词： Electric vehicle Traction drive Zero spin Transmission efficiency EV range

Desulfurization thermodynamics experiment of stainless steel pickling sludge

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Journal of Iron and Steel Research(International) 2019年第5期26卷 519-528页

作者： Xiao-ming Li Ming Lv wei-dong Yin jun-xue Zhao Ya-ru Cui School of Metallurgical Engineering Xi'an University of Architecture and Technology Xi'an 710055 Shaanxi China Research Center of Metallurgical Engineering and Technology of Shaanxi Province Xi'an University of Architecture and Technology Xi'an 710055 Shaanxi China

A technical idea of returning stainless steel pickling sludge to smelting process so as to recycle valuable metals of Fe, Cr, and Ni was proposed, expecting to realize sludge detoxification and resource utilization. Thermodynamics calculation showed that not only most valuable elements including Fe, Cr and Ni, but also the harmful element of sulfur in pickling sludge can be enriched into molten metal. As a result, a theoretical study on desulfurization thermodynamics of sludge pretreatment was conducted, and results indicated that complete desulfurization temperature of pure pickling sludge was above 1400℃. When 0.5-0.8% carbon was added as reducing agent, the complete desulfurization temperature was reduced to 1000℃ or below. Desulfurization roasting experiment indicated that desulfurization rate at 1400℃ under inert environment was 78.74% and maximum desulfurization rate at 1000℃ under reducing environment was 91.62%.

关键词： Stainless steel Pickling sludge Pre-treatment Desulfurization thermodynamics

Probing Intermittent Motion of Polymer Chains in Weakly Attractive Nanocomposites

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Chinese Journal of Polymer Science 2020年第6期38卷 620-628页

作者： Li-jun Dai Cui-Liu Fu You-Liang Zhu Zhan-wei Li Zhao-Yan Sun State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China University of Chinese Academy of Sciences Beijing 100049China

In this study,we investigate the motion of polymer segments in polymer/nanoparticle composites by varying nanoparticle(NP)volume fractions.By studying the probability distribution of segment displacement,segment trajectory,and the square displacement of segment,we find the intermittent motion of segments,accompanied with the coexistence of slow and fast segments in polymer nanocomposites(PNCs).The displacement distribution of segments exhibits an exponential tail,rather than a Gaussian form.The intermittent dynamics of chain segments is comprised of a long-range jump motion and a short-range localized motion,which is mediated by the weakly attractive interaction between NP and chain segment and the strong confinement induced by NPs.Meanwhile,the intermittent motion of chain segments can be described by the adsorption-desorption transition at low particle loading and confinement effect at high particle loading.These findings may provide important information for understanding the anomalous motion of polymer chains in the presence of NPs.

关键词： Nanocomposites Intermittent dynamics The probability distribution of displacement Confinement Adsorption-desorption mechanism

Influence of Initial Microstructure on the Strengthening Effect of Extruded Mg–8Sn–4Zn–2Al Alloys

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Acta Metallurgica Sinica(English Letters) 2018年第5期31卷 487-495页

作者： Yang Bai wei-Li Cheng Shi-Chao Ma jun Zhang Chen Guo Yao Zhang School of Materials Science and Engineering Taiyuan University of Technology Shanxi Key Laboratory of Advanced Magnesium-Based Materials Taiyuan University of Technology Key Laboratory of Interface Science and Engineering in Advanced Materials Ministry of Education Taiyuan University of Technology

The Mg–8Sn–4Zn–2Al（TZA842, in wt%） alloys with different initial microstructure（as-cast-AC and homogenization treatment-HT） subjected to hot extrusion. Also, the strengthening responses to AC and HT for the extruded TZA842 alloys were reported. The results revealed that the alloy subjected to HT shows finer grain size, more homogenous microstructure and weaker basal texture than those of counterpart subjected to AC. In addition, compared with TZA842-AC alloy, precipitates were finer and uniformly dispersed in TZA842-HT owing to the utilization of HT. Moreover, the TZA842-HT alloy showed higher yield strength of 200 MPa, ultimate tensile strength of 290 MPa and elongation（EL） of17.9% than those of TZA842-AC, which was mainly attributed to the combined effects of grain boundary strengthening,precipitation strengthening, solid solution strengthening and weak texture. Strengthening mechanism for both alloys was discussed in detail.

关键词： Mg-Sn alloy Extrusion Microstrueture Tensile property Strengthening mechanism