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A beam range monitor based on scintillator and multi-pixel photon counter arrays for heavy ions therapy

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Nuclear Science and Techniques 2022年第10期33卷 11-21页

作者： Wei Wang Xiao-Xiao Yuan Xiao-Hong Cai institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China

Fast beam range measurements are required to maximize the time available for patient treatment, given that the beam range requires verification with respect to quality assurance to maintain accelerator commissioning standards and ensure patient safety. A novel beam range monitor based on a plastic scintillator and multi-pixel photon counter (MPPC) arrays is therefore proposed in this paper. The monitor was constructed using 128 plastic scintillator films with a thickness of 1 mm and an active area of 50 × 50 mm^(2). A customized MPPC array read the scintillation light of each film. The advantage of dividing the active detector volume into films is that it intercepts the particle beam and enables direct differential light yield measurement in each film, in addition to depth-light curve generation without the need for image analysis A GEANT4 simulation, including scintillator quenching effects, was implemented, and the results revealed that Birks’ law exhibited a slight little influence on the position of the beam range, only changing the shape and absolute normalization of the Bragg curve, which is appropriate for the calculation of the beam range using the depth-light curve. The performance of the monitor was evaluated using a heavy-ion medical machine in Wuwei City, gansu Province, China. The beam range measurement accuracy of the monitor was 1 mm, and the maximum difference between the measured and reference ranges was less than0.2%, thus indicating that the monitor can meet clinica carbon ion therapy requirements.

关键词： Beam range Scintillator Multi-pixel photon counter(MPPC) Depth-light curve

Investigation of variable aperture on the performance and lifetime of ion thruster

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Plasma Science and Technology 2021年第10期23卷 11-21页

作者： Juanjuan Chen Yanhui Jia Hai Geng Ning Guo Dezhou Guo National Key Laboratory of Vacuum and Cryogenic Technology on Physics Lanzhou Institute of PhysicsLanzhou 730030People’s Republic of China

Beam flatness is an important parameter that determines the performance and the lifetime of a gridded ion *** improve the beam flatness of the 30 cm(LIPS-300)ion thruster,variable aperture ion optics that adapts to the decreasing ion density as the radius increases is *** is the ion optics that the screen grid surface is divided into several zones,where the aperture diameter in each zone is determined by the ion density and the electron temperature upstream of the screen *** beam current density in the central area is artificially reduced.A particle in cell-Monte Carlo collision model is applied in this work to investigating the effect of variable aperture on the perveance and the maximum beam current per aperture by simulating the extraction,focusing and acceleration processes of *** into account the engineering implementability,the screen grid surface is divided into four *** hole diameter in each zone is decreased from 1.95 mm to 1.8 mm,1.9 mm,1.8 mm and 1.7 mm,*** simulation results show that the maximum ion density in the center area of grid is decreased by10.6%and 6.99%,while it is increased by 6.49%and 22.3%in the edge region,*** beam flatness of the variable aperture ion optics is improved from 0.69 to *** erosion rate is decreased by 31.9%,but the total beam current is also decreased by 7.15%.The simulation results can provide a valuable reference of the development of the ion thruster.

关键词： ion thruster variable aperture PIC-MCC simulation

Oil-soluble ionic liquids as antiwear and extreme pressure additives in poly-α-olefin for steel/steel contacts

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Friction 2019年第1期7卷 18-31页

作者： Guowei HUANG Qiangliang YU Zhengfeng MA Meirong CAI Feng ZHOU Weimin LIU State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical Physics Chinese Academy of Sciences University of Chinese Academy of Sciences

To enhance the lubricating and extreme pressure(EP) performance of base oils, two types of oil-soluble ionic liquids(ILs) with similar anion albeit dissimilar cations were synthesized. The physical properties of the prepared ILs were measured. The anticorrosion properties of ILs were assessed by conducting corrosion tests on steel discs and copper strips, which revealed the remarkable anticorrosion properties of the ILs in comparison with those of the commercial additive zinc dialkyldithiophosphate(ZDDP). The tribological properties of the two ILs as additives for poly-α-olefin-10(PAO10) with various mass concentrations were investigated. The tribological test results indicate that these ILs as additives are capable of reducing friction and wear of sliding contacts remarkably as well as enhance the EP performance of blank PAO10. Under similar test conditions, these IL additives exhibit higher lubricating and anti-wear(AW) performances than those of ZDDP based additive package in PAO10. Subsequently, X-ray photoelectron spectroscopy(XPS) and energy dispersive spectrometer(EDS) were conducted to study the lubricating mechanism of the two ILs. The results indicate that the formation of tribochemical film plays the most crucial role in enhancing the lubricating and AW behavior of the mixture lubricants.

关键词： anti-wear extreme pressure ionic liquids lubricating mechanism

Discovery of a new vertebrate fauna of Late Permian from western gansu and its stratigraphic significance

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Chinese Science Bulletin 1996年第15期41卷 1271-1275页

作者：程政武李佩贤李锦玲姬书安靳悦高 institute of Geology Ministry of Geology and Mineral Resources Beijing 100037 China institute of Vertebrate Paleontology and Paleoanthropology Chinese Academy of Sciences Beijing 100044 China Geological Museum of China Beijing 100034 China

In 1981, the working group for continental Permian and Triassic sequences from the institute of Geology, Ministry of Geology and Mineral Resources, and gansu institute of Geology and Mineral Resources under gansu Bureau of Geology and Mineral Resources made an investigation on the Permian and Triassic strata and found some vertebrate fossils. The three-time excavations in 1981, 1982 and 1985 proved that Dashankou of Yumen

关键词： western gansu Late Permian Dashankou Fauna.

Effectiveness of an Indoor Air Pollution (IAP) Intervention on Reducing IAP and Improving Women’s Health Status in Rural Areas of gansu Province, China

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Open Journal of Air Pollution 2015年第1期4卷 26-37页

作者： Yibin Cheng Jiaqi Kang Fan Liu Bryan A. Bassig Brian Leaderer Gongli He Theodore R. Holford Ning Tang Jian Wang Jian He Yanchang Liu Yingchun Liu Jiang Liu Xun Chen Heng Gu Xiao Ma Tongzhang Zheng Yinlong Jin institute for Environmental Health and Related Product Safety Chinese Center for Disease Control and Prevention Beijing China Yale School of Public Health New Haven USA Chinese Center for Disease Control and Prevention Beijing China gansu Provincial Center for Disease Control and Prevention Lanzhou China West China School of Public Health Sichuan University Chengdu China

Given the deleterious health effects associated with indoor air pollution (IAP), this study was conducted to evaluate an IAP intervention in rural areas in gansu, one of the poorest provinces of China. We selected 371 rural households to take part in intervention measures including stove improvement and health education. Eight of 371 households were selected to conduct IAP sampling. Four hundred and thirteen women in these households completed a questionnaire and 49 women took part in lung function tests. After the intervention, PM4 levels reduced from 455 μg/m3 to 200 μg/m3 and CO reduced from 3.40 ppm to 2.90 ppm in indoor air. The percentage of predicted value of FEV1 and FVC improved to some degree after the intervention, but all the parameters of lung function assessment did not show a significant change. Prevalence rates of several symptoms associated with IAP significantly declined in the study population, compared with baseline levels. Intervention measures combining stove improvement with health education were effective in reducing IAP levels. Women’s health status, including eye and respiratory symptoms, also showed improvement. However, the effect on lung function was not apparent and warranted additional follow-up. Similarly, evaluation of the long term effects of the IAP intervention will require future studies.

关键词： Indoor Air Pollution Biomass Lung Function Respiratory System

Effects of Maca Extract on Exercise Endurance and Ultrastructure of Mitochondria in Spinal Neurons

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Medicinal Plant 2018年第3期9卷 47-50页

作者： Farong YU Wangjun CHEN Xiuzhen LIAN Mingren XIE Denglou LI Yunxuan GUO Key Laboratory of Evidence of Science and Technology Research and Application Gansu Institute of Political Science and Law

[Objectives] To study the effects of maca extract on the exercise endurance and ultrastructure of mitochondria in spinal neurons.[Methods]First,50 Wistar rats were randomly divided into 5 groups. The control group: no swimming,administered intragastrically the same volume of distilled water; simple swimming group: free swimming,administered intragastrically the same volume of distilled water; maca extract groups: free swimming,and treated with 4. 0,5. 3,and 8. 0 g/kg dose of maca extracts. Swimming rats swam freely in the circulating water flow of swimming pool and administered for 15 d. On the 16 th d,after the swimming endurance test,the rats were killed painlessly. The ultrastructure of the mitochondria in the spinal neurons was observed with a projection electron microscope,muscle glycogen,malondialdehyde( MDA),superoxide dismutase( SOD),glutathione peroxidase( GSH-Px) and free calcium in muscle were measured by radioimmunoassay.[Results] Compared with the simple swimming group,the swimming time before sinking and total swimming time extended 19. 83%,60. 28%,77. 55% and 55. 34%,73. 91% and 94. 47% respectively,and the differences were statistically significant( P < 0. 01). The sinking times decreased by 34. 35%,51. 18% and 57. 96% respectively,the differences were statistically significant( P < 0. 01). MDA and free calcium decreased by 20. 10%,31. 49% and 38. 72%,respectively with statistically significant differences( P < 0. 01) and 6. 42%,17. 58%and 26. 35% respectively. The levels of SOD,GSH-Px and muscle glycogen increased by 5. 12%,22. 74%,52. 53%,44. 22%,77. 79%and 98. 45% respectively,with statistically significant differences( P < 0. 01) and 35. 08%,47. 83% and 81. 88%,respectively,with statistically significant differences( P < 0. 01). The volume density( Vd),surface density( Sd) and number density( Nd) of mitochondria of spinal neurons decreased by 7. 79%,18. 18%,31. 17%,16. 95%,27. 34%,43. 31% and 13. 51%,23. 19% and 43. 15% respectively.[Conclusions]

关键词： Maca extract Exercise endurance Mitochondria Wistar rats

A chromosome-scale genome assembly of Artemisia argyi reveals unbiased subgenome evolution and key contributions of gene duplication to volatile terpenoid diversity

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Plant Communications 2023年第3期4卷 228-243页

作者： Hongyu Chen Miaoxian Guo Shuting Dong Xinling Wu Guobin Zhang Liu He Yuannian Jiao Shilin Chen Li Li Hongmei Luo Key Laboratory of Chinese Medicine Resources Conservation State Administration of Traditional Chinese Medicine of the People’s Republic of ChinaInstitute of Medicinal Plant DevelopmentChinese Academy of Medical Sciences&Peking Union Medical CollegeBeijing 100193China Shandong University of Traditional Chinese Medicine Jinan 250355China State Key Laboratory of Crop Biology Shandong Agricultural UniversityTaian 271018China College of Agronomy Shandong Agricultural UniversityTaian 271018China State Key Laboratory of Systematic and Evolutionary Botany Institute of BotanyChinese Academy of SciencesBeijing 100093China University of the Chinese Academy of Sciences Beijing 100049China institute of Chinese materia medica China Academy of Chinese Medical SciencesBeijing 100700China Chengdu University of Traditional Chinese Medicine Chengdu 611137China Robert W.Holley Center for Agriculture and Health USDA-ARSCornell UniversityIthacaNY 14853USA Plant Breeding and Genetics Section School of Integrative Plant ScienceCornell UniversityIthacaNY 14853USA

Artemisia argyi Le´*** Vant.,a perennial Artemisia herb with an intense fragrance,is widely used in traditional medicine in China and many other Asian ***,we present a chromosome-scale genome assembly of *** comprising 3.89 Gb assembled into 17 *** and comparative genomic analyses revealed that *** underwent a recent lineage-specificwhole-genomeduplication(WGD)event after divergence fromArtemisia annua,resulting in two *** the diploid ancestral genome of ***,and unbiased subgenome evolution was *** recent WGD led to a large number of duplicated genes in the *** *** of the terpene synthase(TPS)gene family through various types of gene duplication may have greatly contributed to the diversity of volatile terpenoids in *** particular,we identified a typical germacrene D synthase gene cluster within the expanded TPS gene *** entire biosynthetic pathways of germacrenes,(+)-borneol,and(+)-camphor were elucidated in *** addition,partial deletion of the amorpha-4,11-diene synthase(ADS)gene and loss of function of ADS homologs may have resulted in the lack of artemisinin production in *** study provides newinsights into the genome evolution of Artemisia and lays a foundation for further improvement of the quality of this important medicinal plant.

关键词： Artemisia argyi subgenome evolution gene duplication terpene synthase germacrene synthase nonartemisinin production

Research advances in interactions related to Toxoplasma gondii microneme proteins

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Research advances in interactions related to Toxoplasma gond...

Study on potential evapotranspiration and wet-dry condition in the seasonal frozen soil region of northern Tibetan Plateau

第五届全国人畜共患病学术研讨会

作者： Fa-Cai Li Qing Liu Chun-Xue Zhou Xing-Quan Zhu State Key Laboratory of Veterinary Etiological Biology Key Laboratory of Veterinary Parasitology of Gansu ProvinceLanzhou Veterinary Research InstituteChinese Academy of Agricultural Sciences College of Veterinary Medicine Hunan Agricultural University National Animal Protozoa Laboratory and College of Veterinary Medicine China Agricultural University

Toxoplasma gondii microneme proteins(TgMICs),secreted by micronemes upon contact with host cells,are reported to play important roles in multiple stages of the *** life cycle,including parasite motility,invasion,intracellular survival,and egress from host ***,during these processes,TgMICs participate in many protein-protein and protein-carbohydrate interactions,such as undergoing proteolytic maturation,binding to aldolase,engaging the host cell

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来源： cnki会议评论

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Research in Cold and Arid Regions 2011年第2期3卷 172-178页

作者： HuiGen He ZeYong Hu XueYi Xun Jun Sun Li Hao LiJiao Xu Wen Peng Nagqu Station of Plateau Climate and Environment Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou Gansu 730000 China Chongqing Climate Center Chongqing 401147 China Inner Mongolia Autonomous Region Meteorological Observatory Hohhot Inner Mongolia 010051 China Shaanxi Province Climate Center Xi ＇ an Shaanxi 710015 China

This study was based on the CEOP/CAMP-Tibet observed data at AWS （Automatic Weather Station） of MS3478 in the seasonal frozen soil region of northern Tibetan Plateau from March 2007 to February 2008. The variation characteristics of PE （potential evapotransph＇ation） were analyzed based on the Penman-Monteith method recommended by FAO （the Food and Agriculture Organization of the United Na- lions）. The contributions of dynamic, thermal and water factors to PE were discussed, and the wet-dry condition of the plateau region was further studied. The results indicated that daily PE was between 0.52 mm and 6.46 mm for the whole year. Monthly PE was over 107 mm from May to September, but decreased to less than 41 mm from November to February. Annual PE was 1,037.8mm. In the summer, thermal PE was significantly more than dynamic PE, but conversely in the winter. Annual variation of thermal PE was of sine wave pattern. In addition, drought and semi-drought climate lasted for a long time while semi-humid climate was short. The effect of water and dynamic factors on PE varied considerably with the seasons. Annual variation of thermal PE was of sine wave pattern.

关键词： northern Tibetan Plateau seasonal frozen soil region potential evapolranspimtion dynamic and thermal effects water factor wet -dry condition