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Nuclear Science and Techniques 2024年第3期35卷 40-52页

作者： Ding-Han Zhu Xiong Zhang xiao-qiang li Peng li Yan-Bin Wang Shuang Zhang State Key Laboratory of NBC Protection for Civilian Beijing 102205China

In high-altitude nuclear detonations,the proportion of pulsed X-ray energy can exceed 70%,making it a specific monitoring signal for such *** pulsed X-rays can be captured using a satellite-borne X-ray detector following atmospheric *** quantitatively analyze the effects of different satellite detection altitudes,burst heights,and transmission angles on the physical processes of X-ray transport and energy fluence,we developed an atmospheric transmission algorithm for pulsed X-rays from high-altitude nuclear detonations based on scattering *** proposed method is an improvement over the traditional analytical method that only computes direct-transmission *** traditional analytical method exhibits a maximum relative error of 67.79% compared with the Monte Carlo *** improved method reduces this error to within 10% under the same conditions,even reaching 1% in certain ***,its computation time is 48,000 times faster than that of the Monte Carlo *** results have important theoretical significance and engineering application value for designing satellite-borne nuclear detonation pulsed X-ray detectors,inverting nuclear detonation source terms,and assessing ionospheric effects.

关键词： High-altitude nuclear detonation Atmospheric transmission Pulsed X-rays Scattering correction Analytical method Monte Carlo method

Effect of short-time low-temperature austenitizing on microstructure and mechanical properties of DT300 ultra-high strength steel fabricated by laser powder bed fusion

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Journal of Iron and Steel Research International 2024年第7期31卷 1763-1777页

作者： Chen-yang Jiang xiao-qiang li Jin-tao Wang Hao Luo Sheng-qing Gao Sheng-guan Qu Chao Yang National Engineering Research Centre of Near-Net-Shape Forming for Metallic Materials South China University of TechnologyGuangzhou 510640GuangdongChina Institute of New Materials Guangdong Academy of ScienceGuangzhou 510650GuangdongChina

To address the inhomogeneous microstructure and improve the mechanical properties of DT300 ultra-high strength steel specimens fabricated by laser powder bed fusion,different post-heat treatment schedules are *** the increase in austenitizing temperature and time,the migration rate of austenite grain boundaries continuously increases with the dissolution of nano-carbides,and the formation of nano-oxides and twin martensite is also inhibited *** rapid growth in the size of prior austenite grains and martensite laths,as well as the decrease in the content of nano-oxides and twin martensite,led to a rapid decrease in the strength(yield strength and ultimate tensile strength)from HT2 to HTF *** HT1 specimens(austenitizing at 830℃for 30 min,then oil quenching and tempering at 300℃for 120 min and finally air cooling)display excellent mechanical properties of yield strength of 1572 MPa,ultimate tensile strength of 1847 MPa,elongation of 9.84%,and fracture toughness of 106 MPa m^(1/2),which are counterparts to those of conventional DT300 steel forgings after heat treatment.

关键词： DT300 ultra-high strength steel Laser powder bed fusion-Short-time low-temperature austenitizing Microstructure Mechanical property

Effect of brazing temperature on microstructure and tensile strength ofγ-TiAl joint vacuum brazed with micro-nano Ti−Cu−Ni−Nb−Al−Hf filler

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Transactions of Nonferrous Metals Society of China 2024年第8期34卷 2563-2574页

作者： li li Yu-tong CHEN Lei-xin YUAN Fen LUO Zhi-xue FENG xiao-qiang li School of Materials Science and Engineering East China Jiaotong UniversityNanchang 330013China State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure East China Jiaotong UniversityNanchang 330013China National Engineering Research Center of Near-net-shape Forming for Metallic Materials South China University of TechnologyGuangzhou 510640China

A novel micro-nano Ti−10Cu−10Ni−8Al−8Nb−4Zr−1.5Hf filler was used to vacuum braze Ti−47Al−2Nb−2Cr−0.15B alloy at 1160−1220°C for 30 *** interfacial microstructure and formation mechanism of TiAl joints and the relationships among brazing temperature,interfacial microstructure and joint strength were emphatically *** show that the TiAl joints brazed at 1160 and 1180°C possess three interfacial layers and mainly consist ofα2-Ti3Al,τ3-Al3NiTi2 and Ti2Ni,but the brazing seams are no longer layered and Ti2Ni is completely replaced by the uniformly distributedτ3-Al3NiTi2 at 1200 and 1220°C due to the destruction ofα2-Ti3Al barrier *** transformation at 1200°C obviously improves the tensile strength of the joint and obtains a maximum of 343 ***,the outward diffusion of Al atoms from the dissolution of TiAl substrate dominates the microstructure evolution and tensile strength of the TiAl joint at different brazing temperatures.

关键词： γ-TiAl alloy micro-nano filler vacuum brazing interfacial microstructure tensile strength

Enhanced recovery after surgery in elderly patients with non-small cell lung cancer who underwent video-assisted thoracic surgery

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World Journal of Clinical Cases 2024年第12期12卷 2040-2049页

作者： Mei-Hua Sun liu-Sheng Wu Ying-Yang Qiu Jun Yan xiao-qiang li Department of Thoracic Surgery Peking University Shenzhen HospitalShenzhen 518036Guangdong ProvinceChina School of Medicine Tsinghua UniversityBeijing 100084China Yong Loo lin School of Medicine National University of SingaporeSingapore 119077Singapore

BACKGROUND This study was designed to investigate the clinical outcomes of enhanced recovery after surgery(ERAS)in the perioperative period in elderly patients with nonsmall cell lung cancer(NSCLC).AIM To investigate the potential enhancement of video-assisted thoracic surgery(VATS)in postoperative recovery in elderly patients with *** We retrospectively analysed the clinical data of 85 elderly NSCLC patients who underwent ERAS(the ERAS group)and 327 elderly NSCLC patients who received routine care(the control group)after VATS at the Department of Thoracic Surgery of Peking University Shenzhen Hospital between May 2015 and April *** propensity score matching of baseline data,we analysed the postoperative stay,total hospital expenses,postoperative 48-h pain score,and postoperative complication rate for the 2 groups of patients who underwent lobectomy or sublobar *** After propensity score matching,ERAS significantly reduced the postoperative hospital stay(6.96±4.16 vs 8.48±4.18 d,P=0.001)and total hospital expenses(48875.27±18437.5 vs 55497.64±21168.63 CNY,P=0.014)and improved the satisfaction score(79.8±7.55 vs 77.35±7.72,P=0.029)relative to those for routine *** significant between-group difference was observed in postoperative 48-h pain score(4.68±1.69 vs 5.28±2.1,P=0.090)or postoperative complication rate(21.2%vs 27.1%,P=0.371).Subgroup analysis showed that ERAS significantly reduced the postoperative hospital stay and total hospital expenses and increased the satisfaction score of patients who underwent lobectomy but not of patients who underwent sublobar *** ERAS effectively reduced the postoperative hospital stay and total hospital expenses and improved the satisfaction score in the perioperative period for elderly NSCLC patients who underwent lobectomy but not for patients who underwent sublobar resection.

关键词： Enhanced recovery after surgery Non-small cell lung cancer Perioperative care Propensity score Video-assisted thoracic surgery

Pathological diagnosis and immunohistochemical analysis of giant retrosternal goiter in the elderly: A case report

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World Journal of Clinical Cases 2024年第3期12卷 643-649页

作者： Yong-Chang Meng liu-Sheng Wu Ning li Hong-Wei li Jing Zhao Jun Yan xiao-qiang li Peng li Jiang-Qi Wei Department of Cardiothoracic Surgery Xinxiang First People's HospitalXinxiang 453000Henan ProvinceChina School of Clinical Medicine Tsinghua UniversityBeijing 100084China Graduate School Qinghai UniversityXining 810016Qinghai ProvinceChina Department of Pathology Xinxiang First People's HospitalXinxiang 453000Henan ProvinceChina Department of Thoracic Surgery Peking University Shenzhen HospitalShenzhen 518036Guangdong ProvinceChina

BACKGROUND Elderly giant retrosternal thyroid goiter is a rare yet significant medical condition,often presenting clinical symptoms that can be confused with other diseases,posing diagnostic and therapeutic *** study aims to delve into the characteristics and potential mechanisms of this ailment through pathological diagnosis and immunohistochemical analysis,providing clinicians with more precise diagnostic and treatment strategies.A 77-year-old male,was admitted to hospital with the chief complaint of finding a goiter in the semilunar month during physical examination,accompanied by *** protruding into the superior mediastinum,the adjacent structure was compressed,the trachea was compressed to the right,and the local lumen was slightly *** patient was diagnosed with giant retrosternal *** dyspnea caused by trachea compression,our department planned to perform giant retrosternal *** results:Tg(+),TTF-1(+),Calcitonin(CT)(I),Ki-67(+,about 20%),CD34(-).Retrosternal goiter means that more than 50%of the volume of the thyroid gland is below the upper margin of the *** retrosternal goiter disease is a relatively rare disease,once the disease is diagnosed,it should be timely surgical treatment,and the treatment is more difficult,the need for professional medical team for comprehensive *** The imaging manifestations of giant retrosternal goiter are atypical,histomorphology and immunohistochemistry can assist in its *** article reviews the relevant literature of giant retrosternal goiter immunohisto-chemistry and shows that giant retrosternal goiter is positive for Tg,TTF-1,and Ki-67.

关键词： Giant retrosternal goiter Pathology Immunohistochemistry Case report

Al_(2)O_(3)改性等离子喷涂-物理气相沉积热障涂层的异物损伤行为及失效机理

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Transactions of Nonferrous Metals Society of China 2024年第7期34卷 2289-2303页

作者：王梓帆范佳锋康楷雯吴健刘敏周克崧张乾张志波李小强张小锋西安理工大学应用化学系西安710048 广东省科学院新材料研究所现代材料表面工程技术国家工程实验室广东省现代表面工程技术重点实验室广州510650 华南理工大学国家金属材料近净成形工程技术研究中心广东省先进金属材料制造与成型重点实验室广州510640

由外来异物损伤引起的颗粒冲蚀是制约热障涂层使用寿命的重要因素。为了提高等离子喷涂-物理气相沉积(PS-PVD)热障涂层的耐冲蚀性能,采用磁控溅射和真空热处理在PS-PVD喷涂的7YSZ热障涂层表面制备一层致密的α-Al_(2)O_(3)。系统研究热... 详细信息

由外来异物损伤引起的颗粒冲蚀是制约热障涂层使用寿命的重要因素。为了提高等离子喷涂-物理气相沉积(PS-PVD)热障涂层的耐冲蚀性能,采用磁控溅射和真空热处理在PS-PVD喷涂的7YSZ热障涂层表面制备一层致密的α-Al_(2)O_(3)。系统研究热障涂层的异物损伤行为,并采用第一性原理计算对α-Al_(2)O_(3)/c-ZrO_(2)界面进行研究。结果表明,PS-PVD、大气等离子喷涂(APS)和电子束-物理气相沉积(EB-PVD)热障涂层的冲蚀质量损失率分别为324、248和139μg/g,而Al_(2)O_(3)改性的PS-PVD热障涂层的冲蚀质量损失率降至199μg/g。此外,在Al_(2)O_(3)/ZrO_(2)-O的顶部构型模型中观察到的界面结合能最高(3.88 J/m^(2)),远高于ZrO_(2)/Ni(2.011 J/m^(2)),使界面结合性能得以提高。

关键词：热障涂层等离子喷涂-物理气相沉积 Al_(2)O_(3)改性外来异物损伤第一性原理

Tunneling of Dirac Particles from Kaluza-Klein Black Hole

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Communications in Theoretical Physics 2009年第5期51卷 849-852页

作者： ZENG xiao-Xiong li qiang Department of Physics and Engineering Technology Sichuan University of Arts and Science Dazhou 635000 China

Applying the fermions tunneling method, proposed by Kerner and Mann recently, we discuss the tunneling characteristics of Dirac particles from the stationary Kaluza-Klein black hole. To choose Gamma matrix conveniently and avoid the ergosphere dragging effect, we perform it in the dragging coordinate frame. The result shows that Hawking temperature in this case also can be reproduced by the general Dirac equation.

关键词： Hawking radiation Dirac particles tunneling Kaluza Klein black hole

Dinosaur-associated Poaceae epidermis and phytoliths from the Early Cretaceous of China

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National Science Review 2018年第5期5卷 721-727页

作者： Yan Wu Hai-Lu You xiao-qiang li Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences Institute of Vertebrate Paleontology and PaleoanthropologyChinese Academy of Sciences CAS Center for Excellence in life and Paleoenvironment College of Earth Sciences University of Chinese Academy of Sciences

Grasses(Poaceae) are human’s most important crop plants and among the most important extant clades of vascular plants. However, the origin and early evolution of grasses are controversial, with estimated ages from molecular dating ranging between 59 and 129 Ma(million years ago). Here we report the discovery of basalmost grasses from the late Early Cretaceous(Albian, 113-101 Ma) of China based on microfossils(silicified epidermal pieces and phytoliths) extracted from a special structure along the dentition of a basal hadrosauroid(duck-billed dinosaur). Thus, this discovery represents the earliest known grass fossils, and is congruent with previous estimations on grass origin and early evolution calibrated by oldest known fossil grasses, highlighting the role of fossils in molecular dating. This discovery also indicates deep-diverging grasses probably gained broad distribution across both Laurasian and Gondwanan continents during the Barremian(129-125 Ma).

关键词： Poaceae dinosaur phytolith epidermis Early Cretaceous

Research on temperature field of non-uniform heat source model in surface grinding by cup wheel

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Advances in Manufacturing 2019年第3期7卷 326-342页

作者： Shi-Jie Dai xiao-qiang li Hui-Bo Zhang State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of TechnologyTianjin 300130People's Republic of China School of Mechanical Engineering Hebei University of TechnologyTianjin 300130People's Republic of China Hebei Key Laboratory of Robot Perception and Human-Robot Interaction Tianjin 300130People's Republic of China

To address the problems of thermal damage to a workpiece surface caused by the instantaneous high temperature during grinding and the difficulty in monitoring temperature in real time,the temperature field in the case of composite surface grinding by a cup wheel is *** order to predict the grinding temperature,considering material removal and grinding force distribution,a nonuniform heat source model with different function distributions in the circumferential and radial directions in the cylindrical coordinate system is first proposed;then,the analytical model is deduced and the numerical model of the temperature field is established based on the heat source *** validation experiments for grinding temperature field are carried out using a high-definition infrared thermal imager and an artificial *** to the temperature field based on the uniform heat source model,the results based on the non-uniform heat source model are in better agreement with the actual temperature field,and the temperature prediction error is reduced from approximately 23% to 6%.Thus,the present study provides a more accurate theoretical basis for preventing bums in cup wheel surface grinding.

关键词： Non-uniform heat source Temperature filed Surface grinding Cup wheel

Preparation of in situ and ex situ reinforced Fe–10Cr–1Cu–1Ni–1Mo–2C containing NbC particles by milling and hot pressing

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International Journal of Minerals,Metallurgy and Materials 2015年第2期22卷 157-166页

作者： xiao-qiang li Zi-yang li Yong-quan Ye Ke Hu School of Mechanical and Automotive Engineering South China University of Technology

An in situ and ex situ reinforced powder metallurgy （PM） steel was prepared by the combination of high-energy ball milling and subsequent hot pressing of elemental mixed powders of Fe-10Cr-1Cu-1Ni-1Mo-2C by mass with the addition of NbC particles. A 40-h milling pretreatment makes the powder particles nearly equiaxed with an average diameter of-8 μm, and the ferrite grain size is refined to -6 nm. The sintered density reaches 99.0%-99.7% of the theoretical value when the sintering is conducted at temperatures greater than 1000℃ for 30 min. In the sintered bulk specimens, the formation of an in situ M7C3 （M = Cr, Fe, Mo） phase is confirmed. MTC3 carbides with several hundred nanometers in size are uniformly distributed in the matrix. Some ultra-fine second phases of 50-200 nm form around the ex situ NbC and in situ M7C3 particles. The sintered steel exhibits an excellent combination of hardness （〉 Hv 500） and compressive strength （2100-2420 MPa）.

关键词： steel powder metallurgy reinforcement ball milling hot pressing