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Simulation study on thermal performance of two turns helium cryogenic oscillating heat pipe for superconducting accelerator

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Radiation Detection Technology and Methods 2023年第3期7卷 427-434页

作者： Yi Huo changcheng ma Jun Zhang Rui Huang Rui Ge University of Chinese Academy of Sciences BeijingChina Institute of High Energy Physics BeijingChina Hefei University of Technology HefeiChina

Purpose In recent years,with the further development of superconducting technology,superconducting devices have been applied in particle accelerators and synchrotron radiation light source devices.As a new type of heat transfer structure,helium cryogenic oscillating heat pipe can be used to balance local hot spots in superconductors and improve heat transfer performance.Methods In this paper,a two-dimensional two-turns helium cryogenic oscillating heat pipe model is established.The flow performance of helium cryogenic oscillating heat pipe was analyzed by CFD simulation.Results and conclusion The results show that the development of flow pattern in the helium cryogenic oscillating heat pipe first forms bubble flow under the heating of the evaporation section,and then gradually forms slug flow and annular flow.The process consists of initial stage,transition stage and running stage.In the running stage,the effective thermal conductivity of COHP oscillates around 15,000 W/(m·K).

关键词： Cryogenic oscillating heat pipe Helium CFD simulation Superconducting accelerator

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微通道技术在颈椎管肿瘤微创切除术中的应用

北京大学学报（医学版） 2024年第2期56卷 318-321页

作者：林国中马长城吴超司雨杨军北京大学第三医院神经外科北京100191

目的:探讨微通道技术在颈椎管肿瘤微创切除手术中的应用。方法:选择2017年2月至2020年3月于北京大学第三医院神经外科因颈椎管肿物行微创切除手术的51例患者的病例资料进行回顾性分析,其中5例患者肿物位于硬膜外,6例位于硬膜内外,40例... 详细信息

目的:探讨微通道技术在颈椎管肿瘤微创切除手术中的应用。方法:选择2017年2月至2020年3月于北京大学第三医院神经外科因颈椎管肿物行微创切除手术的51例患者的病例资料进行回顾性分析,其中5例患者肿物位于硬膜外,6例位于硬膜内外,40例位于髓外硬膜下(6例位于脊髓腹侧)。肿物最大径0.5~3.0 cm。患者临床表现包括颈肩部或上肢疼痛43例,感觉障碍(麻木)22例,肢体无力8例。所有患者均采用微通道锁孔技术进行肿瘤显露,显微镜下进行肿瘤切除手术。结果:35例切除半侧椎板,12例采用半侧椎板间开窗,2例在半椎板切除或半侧椎板间开窗基础上切除内侧1/4小关节,经解剖间隙(未切除骨质)2例。肿瘤切除程度包括50例全部切除和1例次全切除。肿瘤性质包括36例神经鞘瘤,12例脊膜瘤,2例肠源性囊肿和1例皮样囊肿。术后无感染、脑脊液漏。7例患者出现肢体麻木。平均随访时间15个月(3~36个月),未发现颈椎不稳或后突等畸形,肿瘤均无复发。结论:颈椎管较为宽大,不超过三个节段的颈椎管肿瘤可借助微通道技术进行充分显露,除髓内或恶性肿瘤外,可显微外科切除。患者术后更多颈椎正常结构和肌肉附着得到保留,有利于颈椎保持正常功能,神经电生理监测的辅助有助于避免脊髓或神经损伤。

关键词：微通道椎板间开窗半椎板切除术选择性椎板切除术颈椎管肿瘤稳定性

The Early-Middle Triassic Supervolcano in the Yangtze Block,South China and associated obstacles to biotic recovery

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Geoscience Frontiers 2024年第1期15卷 69-83页

作者： Haifeng Chen Hao Zou MSantosh Huawen Cao Franco Pirajno changcheng Huang Mingcai Hou State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Chengdu University of TechnologyChengduSichuan 610059China College of Earth Science Chengdu University of TechnologyChengduSichuan 610059China School of Earth Sciences and Resources China University of GeosciencesBeijing 100083China Department of Earth Science University of AdelaideAdelaideSA 5005Australia Yonsei Frontier Lab Yonsei UniversitySeoulSouth Korea Centre of Exploration Targeting The University of Western Australia35 Stirling HighwayCrawleyWA 6009Australia

The end-Permian mass extinction was one of the major global crises spanning the entire Early Triassic or longer.Eruptions of volcanos were one of the factors that delayed the biotic recovery after this event.Supervolcano eruptions can cause catastrophic effects on global environment,climate,and life.Here we investigate the tuff layers from Early-Middle Triassic boundary in the Yangtze Block and identify a supervolcano eruption event.The zircon U-Pb ages of the section-Langdai,section-Daijiagou and section-Longmendong tuff samples are 247.1±1.9 ma,247.6±2.0 ma and 247.7±1.7 ma,respectively.These ages mark the Olenekian-Anisian boundary.The zircon grains from the tuff layers have negativeεHf(t)(-15.3 to-0.8),two-stage Hf model(TDM2)ages(1.7 to 2.2 Ga)and display high-δ18O values(mostly>10‰).Clay minerals and quartz dominate the rock composition.The whole rock compositions show that the tuff layers were derived from magma of intermediate to felsic composition,which formed by the remelting of Paleoproterozoic materials of continental crust.The volcanic eruption site is located in the Jinshajiang-Ailaoshan-Song ma suture zone in the southwestern margin of the Yangtze Block.A combination of the closure of the Paleo-Tethys Ocean Basin and the collision of the Indochina Block and South China contributed to the eruption,which was a supervolcano eruption under the active continental margin arc settings.We speculate that this supervolcano eruption might have contributed to the delayed biotic recovery after the end-Permian mass extinction.

关键词： Early-Middle Triassic Tuff layer Supervolcano Yangtze Block Biotic recovery

异戊烷脱氢生成单烯烃的热力学分析及试验研究

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石油炼制与化工 2024年第5期55卷 80-86页

作者：陶劲文刘昌呈李筱玉马爱增王杰广中石化石油化工科学研究院有限公司北京100083

计算了异戊烷脱氢生成各种单烯烃主反应的热力学平衡参数及理论异戊烷平衡转化率,对产物分布规律及温度、压力、氢烃摩尔比对平衡的影响进行了分析,并通过试验研究了工艺条件对Pt-Sn-M Al_(2)O_(3)(M为助剂)催化剂性能和异戊烷脱氢产物... 详细信息

计算了异戊烷脱氢生成各种单烯烃主反应的热力学平衡参数及理论异戊烷平衡转化率,对产物分布规律及温度、压力、氢烃摩尔比对平衡的影响进行了分析,并通过试验研究了工艺条件对Pt-Sn-M Al_(2)O_(3)(M为助剂)催化剂性能和异戊烷脱氢产物分布的影响。试验结果表明,异戊烷脱氢生成的烯烃产物以2-甲基-2-丁烯为最多,其次为2-甲基-1-丁烯,3-甲基-1-丁烯最少。高温、低压及低氢烃摩尔比有利于脱氢反应的进行,但温度过高会导致裂解等副反应增多,使烯烃的选择性下降;压力过低及氢烃摩尔比过小均会使催化剂的积炭速率增大。异戊烷脱氢反应的实际转化率均低于热力学计算所得的平衡转化率,通过选择合适的反应条件,可使异戊烷脱氢反应的实际转化率接近热力学平衡转化率,验证了热力学分析结果的可靠性。

关键词：异戊烷烷烃脱氢热力学烯烃氧化铝

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基于灰色关联度的轴承温度影响因素分析

轴承 2024年第3期 52-57页

作者：邓长城程雪利李辉王蒙蒙马晓杰河南工学院机械工程学院河南新乡453003

为研究角接触球轴承温度的影响因素及其影响程度,对2套7006C角接触球轴承进行了9种工况下的温度测试试验。通过文献跟踪确定影响轴承温度的因素为转速、径向载荷、轴向载荷和填脂量,并计算各因素与轴承温度之间的欧式灰色关联度、模糊... 详细信息

为研究角接触球轴承温度的影响因素及其影响程度,对2套7006C角接触球轴承进行了9种工况下的温度测试试验。通过文献跟踪确定影响轴承温度的因素为转速、径向载荷、轴向载荷和填脂量,并计算各因素与轴承温度之间的欧式灰色关联度、模糊隶属度和模糊灰色关联度,结果表明,各因素对轴承温度影响程度由大到小依次为转速、轴向载荷、径向载荷、填脂量。

关键词：滚动轴承角接触球轴承模糊聚类分析温度载荷转速填脂量

Ecosystem carbon storage and sink/source of temperate forested wetlands in Xiaoxing’anling, northeast China

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Journal of Forestry Research 2022年第3期33卷 839-849页

作者： Biao Wang changcheng Mu Huicui Lu Na Li Yan Zhang Li ma Center for Ecological Research Northeast Forestry UniversityHarbin150040People’s Republic of China Faculty of Forestry Qingdao Agricultural UniversityQingdao266000People’s Republic of China

Wetlands play an important role in the global carbon cycle, but there are still considerable uncertainties in the estimation of wetland carbon storage and a dispute on whether wetlands are carbon sources or carbon sinks. Xiaoxing’anling are one of several concentrated distribution areas of forested wetland in China, but the carbon storage and carbon sink/source of forested wetlands in this area is unclear. We measured the ecosystem carbon storage (vegetation and soil), annual net carbon sequestration of vegetation and annual carbon emissions of soil heterotrophic respiration of five typical forested wetland types (alder swamp, white birch swamp, larch swamp, larch fen, and larch bog) distributed along a moisture gradient in this area in order to reveal the spatial variations of their carbon storage and quantitatively evaluate their position as carbon sink or source according to the net carbon balance of the ecosystems. The results show that the larch fen had high carbon storage (448.8 t ha^(−1)) (6.8% higher than the larch bog and 10.5–30.1% significantly higher than other three wetlands (P < 0.05), the white birch swamp and larch bog were medium carbon storage ecosystems (406.3 and 420.1 t ha^(−1)) (12.4–21.8% significantly higher than the other two types (P < 0.0 5), while the alder swamp and larch swamp were low in carbon storage (345.0 and 361.5 t ha^(−1), respectively). The carbon pools of the five wetlands were dominated by their soil carbon pools (88.5–94.5%), and the vegetation carbon pool was secondary (5.5–11.5%). At the same time, their ecosystem net carbon balances were positive (0.1–0.6 t ha^(−1) a^(−1)) because the annual net carbon sequestration of vegetation (4.0–4.5 t ha^(−1) a^(−1)) were higher than the annual carbon emissions of soil heterotrophic respiration (CO_(2) and CH_(4)) (3.8–4.4 t ha^(−1) a^(−1)) in four wetlands, (the alder swamp being the exception), so all four were carbon sinks while only the alder swamp was a source of carbon emissions (− 2.1 t ha^(−1) a^(−1)) due to a degraded tr

关键词： Temperate forested wetlands Ecosystem carbon storage Carbon sink or source Xiaoxing’anling of China

2 K superfluid helium cryogenic vertical test system for superconducting cavity of ADS Injector I

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Radiation Detection Technology and Methods 2020年第2期4卷 131-138页

作者： Rui Ge Liangrui Sun Miaofu Xu Rui Ye Xiangzhen Zhang Minjing Sang Ruixiong Han Zhuo Zhang Jiehao Zhang Lin Bian Mei Li changcheng ma Tongxian Zhao Yongcheng Jiang Zhengze Chang Shaopeng Li Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China Key Laboratory of Particle Acceleration Physics and Technology Chinese Academy of SciencesBeijing 100049China Center for Superconducting RF and Cryogenics Institute of High Energy PhysicsBeijing 100049China

Purpose The accelerator-driven subcritical system(ADS)is the internationally recognized key technology of nuclear waste problem treatment,of which superconducting proton linac is an important part.With the support of the strategic science and technology pilot project of the Chinese Academy of Sciences,the Institute of High Energy Physics of the Chinese Academy of Sciences took the lead in the research of 325 MHz superconducting proton linac,which is called ADS Injector I.The superconducting accelerator part of ADS Injector I mainly consists of 14 spoke-type superconducting cavities withβ0.12.At the same time,the research work of various cavities with differentβvalues and different frequencies is also carried out to lay the technical and technological foundation for ADS main accelerator.The only way to determine whether the superconducting cavity can reach the design target and whether it can be installed into the cryostat is the vertical test at cryogenic.As the only way to test the microwave performance of the superconducting cavity at low temperature,the vertical test can accurately test the acceleration gradient Eacc and the corresponding quality factor Q0 of the superconducting cavity.The design and construction of the superconducting cavity vertical test facility is based on the practical needs of the pilot project and the long-term development of the superconducting accelerator.Methods This paper mainly introduces the design and construction of the cryogenic vertical test system for the superconducting cavity of ADS Injector I,including the system scheme design,process design,heat load analysis,2 K superfluid helium obtaining method,system commissioning and operation,etc.Results and Conclusion The static heat leakage at 2 K of the 2 K superfluid helium vertical test system of ADS Injector I is 1.624W,which has reached the international advanced level.The 2 K superfluid helium vertical test system of ADS Injector I after constructed not only meets the test requirements of ADS pilot project,but also conducts

关键词： Superconducting cavity Superfluid helium Vertical test facility 2 K cryogenic system

Genomic Recombination of SARS-CoV-2 Subvariants BA.5.2.48 and BF.7.14—China,2023

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China CDC weekly 2023年第14期5卷 318-320页

作者： Zhongxian Zhang Han Li Hongxia ma Wenling Wang Dawei Gao Fei Ye Weibang Huo Yuda Chen changcheng Wu Wenjie Tan National Institute for Viral Disease Control and Prevention Chinese Center for Disease Control and PreventionBeijingChina School of Public Health Baotou Medical CollegeBaotou CityInner Mongolia Autonomous RegionChina Henan Provincial Center for Disease Control and Prevention Zhengzhou CityHenan ProvinceChina Lu’an Municipal Center for Disease Control and Prevention Lu’an CityAnhui ProvinceChina

Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),a single-stranded positive RNA virus,exhibits a high rate of genome mutation and recombination(1–2).Recombinant strains of this virus could potentially affect their binding ability to the ACE2 receptor,which may in turn diminish the protection offered by vaccines and neutralizing antibodies.Notably,the Delta and Omicron recombinations have been collectively referred to as Deltacron(3).Furthermore,XBB.1.5,a recombinant strain resulting from the combination of the BA.2 sublineages BA.2.10.1 and BA.2.75,has demonstrated enhanced transmissibility(4).As such,it is imperative to monitor the genome recombination of SARS-CoV-2 in order to provide valuable insights regarding epidemic and transmission trends.

关键词： acute respiratory collective

穴位贴敷对腹腔镜胃肠手术患者腹胀、腹痛程度的影响

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反射疗法与康复医学 2024年第1期5卷 15-17页

作者：朱海滨李艳梅马红周长城欧阳兆云胡照洋泰安市中医医院普外科山东泰安271000 泰安市中医医院妇科山东泰安271000

目的分析穴位贴敷对腹腔镜胃肠手术患者的影响.方法选取2019年10月—2022年12月该院收治的100例腹腔镜胃肠手术患者为研究对象,按随机数字表法将其分为对照组和观察组,每组50例.对照组采用西医治疗,观察组在对照组基础上加用穴位贴敷治... 详细信息

目的分析穴位贴敷对腹腔镜胃肠手术患者的影响.方法选取2019年10月—2022年12月该院收治的100例腹腔镜胃肠手术患者为研究对象,按随机数字表法将其分为对照组和观察组,每组50例.对照组采用西医治疗,观察组在对照组基础上加用穴位贴敷治疗,持续治疗3d.对比两组的临床疗效、腹胀、腹痛严重程度、胃肠功能恢复情况、不良反应发生情况.结果观察组治疗总有效率为96.00%,高于对照组的82.00%,差异有统计学意义(P﹤0.05);观察组肠鸣音恢复时间为(14.33±2.06)h、首次排气时间为(17.41±2.64)h、首次排便时间为(35.35±4.16)h,均短于对照组的(18.69±2.47)h、(20.57±3.53)h、(39.84±5.26)h,组间差异有统计学意义(P﹤0.05);治疗前,两组腹胀评分、疼痛视觉模拟评分法(VAS)评分相比,组间差异无统计学意义(P﹥0.05);治疗后,观察组腹胀评分为(1.28±0.17)分、VAS评分为(1.05±0.34)分,均低于对照组的(2.01±0.26)分、(2.49±0.63)分,组间差异有统计学意义(P﹤0.05);两组治疗期间均未发生不良反应.结论穴位贴敷能够减轻腹腔镜胃肠手术患者的腹胀、腹痛症状,可加速胃肠功能恢复.

关键词：腹腔镜胃肠手术穴位贴敷不良反应腹胀