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Experimental investigation on the radiation background inside body counters

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Nuclear Science and Techniques 2022年第2期33卷 66-78页

作者： Yu Wang Yuan-Yuan Liu Bin Wu Xiang-Peng Meng jian-Ping Cheng Ying Wang Li-Jiao Wang Yun-Shi xiao Qin-jian cao jian-Feng Zhang Fei Tuo Key Laboratory of Beam Technology of Ministry of Education College of Nuclear Science and TechnologyBeijing Normal UniversityBeijing 100875China Department of Nuclear Safety China Institute of Atomic EnergyBeijing 102413China Department of Health Physics China Institute for Radiation ProtectionTaiyuan 030006China National Institute for Radiological Protection Chinese Center for Disease Control and PreventionBeijing 100088China

In vivo measurement of radioactivity based on various body counters is arguably the leading measure used to determine the distribution and activity of radionuclides in human subjects,such as I-131 in the thyroid,Am-241 in the lungs,and Pb-210 in the *** the measurements,the radiation background is the key factor that determines the sensitivity of the ***,to facilitate in vivo measurements,a well-designed shielding room is required to create a low-background ***,because the compositions of the radiation background are quite complicated,the respective contributions from each source remain obscure,which places a considerable burden on seeking an optimized design of shielding rooms that strikes the optimum balance between the construction cost and background suppression *** this study,we conducted a systematic experimental investigation on the radiation background outside and inside four representative body counters with assorted designs using a variety of radiation detectors,including high-purity germanium detectors,CdZnTe detector,radon emanometer,and gamma-ray *** carefully controlling the experimental conditions and synergetic analysis of the measurement results,in conjunction with previous studies,we separated and determined the relative contributions induced by environmental radiation(4%),airborne radon and its daughters(2%),the normal radioactivity of human subjects arising from K-40(58%),cosmic rays(12%),and radioactivity in shielding materials and measuring instruments(24%).Furthermore,based on these results,we discuss practical guidelines to design a shielding room for body counters.

关键词： Body counter Radiation background Shielding room In vivo measurement

High prevalence of aspirin resistance in elderly patients with cardiovascular disease and metabolic syndrome

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Journal of Geriatric Cardiology 2016年第6期13卷 531-536页

作者： Lin LIU Ying-Hui GAO jian cao Hua-Xin ZHANG Li FAN Guo-Liang HU Yi-Xin HU xiao-Li LI xiao ZOU jian-Hua LI Nanlou Respiratory Disease Department Chinese PLA General Hospital Beijing China Peking University Hepatology Institute Peking University People's Hospital Peking University Beijing China Nanlou Clinical Lab Chinese PLA General Hospital Beijing China Department of Clinical Laboratory of South Building Chinese PLA General Hospital Beijing China Clinical Department of South Building Chinese PLA General Hospital Beijing China

Background Metabolic syndrome is known to be a prothrombotic state. We undertook this study to examine a hypothesis that aspirin resistance may be associated with metabolic syndrome, and to assess other potential determinants of aspirin resistance in patients with cardiovascular disease （CVD）. Methods A total of 469 elderly patients with CVD were recruited. One hundred and seventy-two patients with metabolic syndrome and 297 without metabolic syndrome （control group） received daily aspirin therapy （〉 75 mg） over one month. Platelet aggregation was measured by light transmission aggregometry （LTA）. Aspirin resistance was defined as 〉 20% arachidonic acid （AA）- and 〉 70% adenosine diphosphate （ADP）-induced aggregation according to LTA. Aspirin semi-responders were defined as meeting one （but not both） of these criteria. Results By LTA, 38 of 469 （8.1%） patients were aspirin resistant. The prevalence of aspirin resistance was higher in the metabolic syndrome group compared with the control group [11.6 % vs. 6.6%, odds ratio （OR） = 2.039; 95% confidence interval （CI）： 1.047-3.973]. In the multivariate logistic regression analysis, metabolic syndrome （OR = 4.951, 95% CI： 1.440-17.019, P = 0.011） was a significant risk factor for aspirin resistance. Conclusions A significant number of patients with CVD and metabolic syndrome are resistant to aspirin therapy. This might further increase the risk of cardiovascular morbidity and mortality in these patients.

关键词： Aspirin resistance Cardiovascular disease Metabolic syndrome

Resonance response of fluid-conveying pipe with asymmetric elastic supports coupled to lever-type nonlinear energy sink

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Applied Mathematics and Mechanics(English Edition) 2022年第12期43卷 1873-1886页

作者： Runqing cao Zhijian WANG jian ZANG Yewei ZHANG Faculty of Aerospace Engineering Shenyang Aerospace UniversityShenyang 110136China

This paper studies the vibration absorber for a fluid-conveying pipe,where the lever-type nonlinear energy sink(LNES)and spring supports are coupled to the asymmetric ends of the *** pseudo-arc-length method integrated with the harmonic balance method is used to investigate the steady-state responses ***,the numerical solution of the fluid-conveying pipe is calculated with the Runge-Kutta ***,a special response,called the collapsible closed detached response(CCDR),is first observed when the vibration response of mechanical structures is ***,the relationship between the CCDR and the main structure primary response(PR)is *** addition,the closed detached response(CDR)is also observed to research the resonance response of the fluid-conveying *** appearance of either the CCDR or the CDR does affect the resonance ***,the mentioned two phenomena underline that the trend of vibration responses under external excitation goes continuous and ***,the main advantage of the LNES is presented by contrasting the LNES with the nonlinear energy sink(NES)coupled to the same pipe *** is found that the LNES can reduce the resonance response amplitude by 91.33%.

关键词： fluid-conveying pipe vibration attenuation collapsible closed detached response(CCDR) lever-type nonlinear energy sink(LNES) elastic support

Joining SiO_(2)based ceramics:recent progress and perspectives

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Journal of Materials Science & Technology 2022年第13期108卷 110-124页

作者： Haohan Wang Jinghuang Lin Junlei Qi jian cao State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China

Nowadays,SiO_(2)based material is one of the widest used materials in optical,microelectromechanical system,aerospace and some other *** practical application,SiO_(2)based materials are required to be joined with themselves or other heterogeneous materials to assemble products with various *** the joining quality directly affects the mechanical performances and functional properties of assembled *** many researchers studied different joining technologies,explored the microstructure of joining interface and tested after-joining properties,a review that summarizes the recent cutting-edge researches and development tendency of joining technologies for SiO_(2)based ceramics is still ***,according to different applications and requirements,this review summarizes the widely used joining technologies and discusses corresponding joining mechanisms,current research progress and suitable *** to the wide applications in specific industry,laser welding,anodic bonding and wafer bonding are discussed in ***,brazing,the widest used method in SiO_(2)joining,has been elaborated deeply in its wetting mechanism,residual stress control,interfacial microstructure and mechanical performance *** the end,this review proposed the future development trends of SiO_(2)ceramics joining,aiming at offering a full-view of potential improvements in SiO_(2)ceramic joining technologies.

关键词： SiO_(2)joining current research progress brazing future development trend

Comparison of the carbon cycle and climate response to artificial ocean alkalinization and solar radiation modification

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Advances in Climate Change Research 2023年第2期14卷 322-334页

作者： xiao-Yu JIN Long cao Department of Atmospheric Sciences School of Earth SciencesZhejiang UniversityHangzhou 310058China

Carbon dioxide removal and solar radiation modification(SRM)are two classes of proposed climate intervention methods.A thorough understanding of climate system response to these methods calls for a good understanding of the carbon cycle *** this study,we used an Earth system model to examine the response of global climate and carbon cycle to artificial ocean alkalinization(AOA),a method of CO_(2)removal,and reduction in solar irradiance that represents the overall effect of solar radiation *** our simulations,AOA is applied uniformly over the global ice-free ocean under the RCP8.5 scenario to bring down atmospheric CO_(2)to the level of RCP4.5,and SRM is applied uniformly over the globe under the RCP8.5 scenario to bring down global mean surface temperature to the level of *** simulations show that with the same goal of temperature stabilization,AOA and SRM cause fundamentally different perturbations of the ocean and land carbon *** the end of the 21st century,relative to the simulation of RCP8.5,AOA-induced changes in ocean carbonate chemistry enhances global oceanic CO_(2)uptake by 983 PgC and increases global mean surface ocean pH by ***,AOA reduces land CO_(2)uptake by 79 PgC and reduces atmospheric CO_(2)concentration by 426×10^(−6).By contrast,relative to the simulation of RCP8.5,SRM has a minor effect on the oceanic CO_(2)uptake and ocean ***-induced cooling enhances land CO_(2)uptake by 140 PgC and reduces atmospheric CO_(2)concentration by 63×10^(−6).A sudden termination of SRM causes a rate of temperature change that is much larger than that of RCP8.5.A sudden termination of AOA causes a rate of temperature change that is comparable to that of RCP8.5 and a rate of ocean acidification that is much larger than that of RCP8.5.

关键词： Carbon dioxide removal Solar radiation modification Geoengineering Carbon cycle Ocean acidification

Heat Transfer Characteristics of the Microfluidic Biomimetic Chameleon Skin with Active Thermal Camouflage

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Journal of Bionic Engineering 2023年第2期20卷 722-733页

作者： Lujia Li Huanhuan Li jian cao Songjing Li Department of Fluid Control and Automation Harbin Institute of TechnologyHarbin150001China

Natural organisms have different techniques to avoid enemies,such as chameleon skin with innate camouflage ability to change with the surrounding *** by this,a microfluidic biomimetic chameleon skin based on infrared(IR)information processing is proposed for active thermal camouflage in a dynamic infrared *** circulation in microcavities distributed under the skin is controlled by a thermal camouflage *** structure and working principle of the biomimetic skin are introduced,and the thermal camouflage system is established and tested to explore the heat transfer characteristics between the skin and the *** mechanism of collecting the background infrared information and regulating the skin temperature through the control signal generated by the infrared information processing system is ***,the dynamic thermal response of the skin is tested when transitioning between different temperature backgrounds,modeling the ambient temperature of the sand,woodland and lakes where chameleons *** performance of the skin is evaluated by measuring the camouflage responding time of the skin to an external heat *** results show that the chameleon biomimetic skin is naturally transitioned and matched by infrared information processing and *** limitation that the conventional thermal camouflage technology cannot adapt to the dynamic combat environment is overcome and the weaknesses of a small camouflage band range and a single form of camouflage are resolved in this study,thus effectively improving the target’s survivability in combat.

关键词： Biomimetic skin Thermal camouflage Microfluidics Infrared Chameleon

EVOLUTION AND DEVELOPMENT OF GUANGZHOU-HONG KONG CORRIDOR

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Chinese Geographical Science 2005年第3期15卷 206-211页

作者： LI Ping cao xiao-shu Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 P. R. China School of Geography and Planning Sun Yat-Sen University Guangzhou 510275 P. R. China

With its rapid development in the past two decades, the Pearl River Delta has become one of the most developed regions in China. During this period, an important corridor between Hong Kong and Guangzhou has emerged and shaped the spatial structure of the region. The growth of this region has been greatly marched with the twin poles of Guangzhou and Hong Kong, and the economic and social development has taken place in a corridor between these two metropolises. This paper provides an analysis of the significance of this corridor in terms of its infrastructure, population, land use, and economic development. Massive infrastructure construction in the corridor has played an important role in its development. The corridor has high-frequent transport, and each transport mode has contributed in a different way to the process of development of the corridor. With high land use intensity and high population density, it is developing the characteristics of a megalopolis. As a pathway of connection between Guangzhou and Hong Kong, the corridor includes not only physical infrastructure, such as roads, railways and airports, but also logistics operations, human resources, information and capital, which plays important roles in accelerating business development. It demonstrates how this Main Street has become one of the most important factors in regional development.

关键词： corridor regional development evolution

Force-position collaborative optimization of rope-driven snake manipulator for capturing non-cooperative space targets

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Chinese Journal of Aeronautics 2024年第9期37卷 369-384页

作者： xiaofeng LI jian TIAN Cheng WEI Xibin cao School of Astronautics Harbin Institute of TechnologyHarbin 150001China Beijing Instiuteof Spacecraft System Engineering China Academy of Space TechnolgyBeijing 100094Chia

With the rapid development of space activities,non-cooperative space targets increase swiftly,such as failed satellites and upper stages,threating normal spacecrafts *** there are some problems in the capture process,such as excessive collision and fast tumbling of targets,manipulator with redundant Degrees of Freedom(DOFs)can be used to improve the compliance and therefore solve these *** Rope-Driven Snake Manipulator(RDSM)is a combina-tion of hyper-redundant DOFs and better compliance,and therefore it is suitable for capturing *** this paper,a snake manipulator mechanism is designed,and the complete kinematic model and system dynamic model considering RDSM,target and contact is ***,to obtain the configuration of joint with hyper-redundant DOFs,an improved motion dexterity index is pro-posed as the joint motion optimization ***,the force-position collaborative optimization index is designed to adjust active stiffness,and the impedance control method based on the modified index is used to capture the space ***,the proposed force-position collaborative opti-mization method is verified by virtual prototype *** results demonstrate that based on the proposed method,the collision force is reduced by about 25%compared to normal impe-dance control,showing higher safety.

关键词： Capturing non-cooperative spacetargets Rope-driven snakemanipu-lator Force-position collaborative optimization Redundant degrees of free-dom Active stiffness adjustment

Effect of K-doping on the Electrochemical Performance of Ca_3Co_4O_9 Anode for Li-ion Batteries

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Journal of Materials Science & Technology 2010年第7期26卷 669-672页

作者： Jina cao Hongquan Liu jian Xie caoshao cao Xinbing Zhao Department of Materials Science and Engineering Zhejiang University Hangzhou 310027 China

Ca3CO4O9 （CCO） and Ca2.95K0.05Co4O9 （CKCO） powders have been prepared by the polyacrylamide gel method. CKCO shows increased capacity and better cycling stability compared with CCO. After cycled for 50 cycles at 0.5 C, CKCO retains a capacity of 223 mAh.g-1, almost twice than CCO. The electrochemical impedance spectroscopy （EIS） tests shows the CKCO sample has a lower initial charge transfer resistance （Rot） and undergoes smaller Rot change during cycling than the CCO sample, indicating improved electrochemical performance by K-doping.

关键词： Lithium-ion battery Anode Ca3Co4O9 K-doping