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分子水平上的虚拟仿真实验之思政元素的挖掘与提炼——以“高分子的构象、形态及尺寸的模拟与计算”项目为例
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作者 朱平平 谢永军 +5 位作者 易院平 黄渝 周强 肖石燕 杨海洋 何平笙 《大学化学》 CAS 2024年第2期83-88,共6页
高分子的构象、形态及尺寸的模拟与计算,是分子水平上的虚拟仿真实验项目,结合诺贝尔奖获得者de Gennes和P.J.Flory的理论工作、由项目组自身教研成果转化、师生合作研发而成。与小分子化合物相比,高分子的研究方法有很大的不同,特别是... 高分子的构象、形态及尺寸的模拟与计算,是分子水平上的虚拟仿真实验项目,结合诺贝尔奖获得者de Gennes和P.J.Flory的理论工作、由项目组自身教研成果转化、师生合作研发而成。与小分子化合物相比,高分子的研究方法有很大的不同,特别是需要采用统计方法来描述高分子链的构象、形态,计算高分子链的平均尺寸,这是经典的物理化学方法所不能完成的。本项目从研发到教学实践、再经改进,教学内容的更新优化中,自然融入了诺贝尔奖成果、哲学思想、科学思维、学科发展史、教研成果等多个维度的思政元素。 展开更多
关键词 分子水平上的虚拟仿真实验 量变引起质变 科学思维 诺贝尔奖成果 高分子链的柔性
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热损伤玉米种子的高光谱无损检测
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作者 张伏 禹煌 +6 位作者 熊瑛 张方圆 王新月 吕庆丰 武一戈 张亚坤 付三玲 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2024年第4期1165-1170,共6页
玉米是世界主要粮食作物之一,使用不符合国家标准的劣质种子将严重影响玉米作物产量,如何快速准确高效鉴别劣质玉米种子亟待解决。采用高光谱图像系统获取900粒“豫安三号”玉米种子的900~1700 nm光谱曲线,其中训练集和测试集比例为3∶2... 玉米是世界主要粮食作物之一,使用不符合国家标准的劣质种子将严重影响玉米作物产量,如何快速准确高效鉴别劣质玉米种子亟待解决。采用高光谱图像系统获取900粒“豫安三号”玉米种子的900~1700 nm光谱曲线,其中训练集和测试集比例为3∶2,分别为540粒和360粒。利用电鼓风式烘干箱对种子损伤处理,获得不同损伤程度的玉米种子样本,采集光谱后完成发芽试验,以此判别种子活力。为提高信噪比,截取963.27~1698.75 nm范围内的玉米种子光谱波段作为有效波段;采用标准正态变换(SNV)、多元散射校正(MSC)两种预处理方式对原始光谱数据预处理,并采用连续投影算法(SPA)、竞争性自适应重加权算法(CARS)两种特征波段提取算法对预处理后的光谱数据提取特征波段,波长反射率作为输入矩阵X,预设样本类别作为输出矩阵Y;最后采用支持向量机(SVM)模型建模分析,研究结果表明:MSC-CARS-SVM模型为最佳模型,模型识别成功率为98.33%,其Kappa系数为0.985。在此基础上,采用遗传算法(GA)对SVM中惩罚系数c和核函数参数g寻优,模型准确率提升至100%,可实现对热损伤劣质玉米种子的鉴别。该研究为劣质玉米种子及其他作物种子快速鉴别提供了新思路和方法。 展开更多
关键词 高光谱成像技术 玉米种子 热损伤 支持向量机
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Interaction Mechanisms between Natural Debris Flow and Rigid Barrier Deflectors:A New Perspective for Rational Design and Optimal Arrangement
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作者 yu huang Beilei Liu +1 位作者 Dianlei Feng Hao Shi 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第5期1679-1699,共21页
Rigid barrier deflectors can effectively prevent overspilling landslides,and can satisfy disaster prevention requirements.However,the mechanisms of interaction between natural granular flow and rigid barrier deflector... Rigid barrier deflectors can effectively prevent overspilling landslides,and can satisfy disaster prevention requirements.However,the mechanisms of interaction between natural granular flow and rigid barrier deflectors require further investigation.To date,few studies have investigated the impact of deflectors on controlling viscous debris flows for geological disaster prevention.To investigate the effect of rigid barrier deflectors on impact mechanisms,a numerical model using the smoothed particle hydrodynamics(SPH)method with the Herschel–Bulkley model is proposed to simulate the interaction between natural viscous flow and single/dual barriers with and without deflectors.This model was validated using laboratory flume test data from the literature.Then,the model was used to investigate the influence of the deflector angle and multi-barrier arrangements.The optimal configuration of multi-barriers was analyzed with consideration to the barrier height and distance between the barriers,because these metrics have a significant impact on the viscous flow pile-up,run-up,and overflow mechanisms.The investigation considered the energy dissipation process,retention efficiency,and dead-zone formation.Compared with bare barriers with similar geometric characteristics and spatial distribution,rigid barriers with deflectors exhibit superior effectiveness in preventing the overflow and overspilling of viscous debris flow.Recommendations for the rational design of deflectors and the optimal arrangement of multi-barriers are provided to mitigate geological disasters. 展开更多
关键词 Rigid barrier deflectors deflector angle single-barrier dual-barrier arrangements viscous debris flow over-spilling delta-plus-SPH
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Tumor microenvironment reprogramming by nanomedicine to enhance the effect of tumor immunotherapy
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作者 yu huang Hui Fan Huihui Ti 《Asian Journal of Pharmaceutical Sciences》 SCIE CAS 2024年第2期1-37,共37页
With the rapid development of the fields of tumor biology and immunology, tumor immunotherapy has been used in clinical practice and has demonstrated significant therapeutic potential, particularly for treating tumors... With the rapid development of the fields of tumor biology and immunology, tumor immunotherapy has been used in clinical practice and has demonstrated significant therapeutic potential, particularly for treating tumors that do not respond to standard treatment options. Despite its advances, immunotherapy still has limitations, such as poor clinical response rates and differences in individual patient responses, largely because tumor tissues have strong immunosuppressive microenvironments. Many tumors have a tumor microenvironment (TME) that is characterized by hypoxia, low pH, and substantial numbers of immunosuppressive cells, and these are the main factors limiting the efficacy of antitumor immunotherapy. The TME is crucial to the occurrence, growth, and metastasis of tumors. Therefore, numerous studies have been devoted to improving the effects of immunotherapy by remodeling the TME. Effective regulation of the TME and reversal of immunosuppressive conditions are effective strategies for improving tumor immunotherapy. The use of multidrug combinations to improve the TME is an efficient way to enhance antitumor immune efficacy. However, the inability to effectively target drugs decreases therapeutic effects and causes toxic side effects. Nanodrug delivery carriers have the advantageous ability to enhance drug bioavailability and improve drug targeting. Importantly, they can also regulate the TME and deliver large or small therapeutic molecules to decrease the inhibitory effect of the TME on immune cells. Therefore, nanomedicine has great potential for reprogramming immunosuppressive microenvironments and represents a new immunotherapeutic strategy. Therefore, this article reviews strategies for improving the TME and summarizes research on synergistic nanomedicine approaches that enhance the efficacy of tumor immunotherapy. 展开更多
关键词 Tumor immunotherapy Tumor micr oenvir onment NANOMEDICINE Tumor repr ogramming
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Magnetism, heat capacity, magnetocaloric effect, and magneto-transport properties of heavy fermion antiferromagnet CeGaSi
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作者 张黎博 董庆新 +8 位作者 白建利 刘乔宇 程靖雯 李存东 刘品宇 孙英睿 黄宇 任治安 陈根富 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第6期495-502,共8页
We synthesize high-quality single crystal of CeGaSi by a Ga self-flux method and investigate its physical properties through magnetic susceptibility,specific heat and electrical resistivity measurements as well as hig... We synthesize high-quality single crystal of CeGaSi by a Ga self-flux method and investigate its physical properties through magnetic susceptibility,specific heat and electrical resistivity measurements as well as high pressure effect.Magnetic measurements reveal that an antiferromagnetic order develops below T_(m)~10.4 K with magnetic moments orientated in the ab plane.The enhanced electronic specific heat coefficient and the negative logarithmic slope in the resistivity of CeGaSi indicate that the title compound belongs to the family of Kondo system with heavy fermion ground states.The max magnetic entropy change-ΔS_(M)^(max)(μ_(0)H⊥c,μ_(0)H=7 T) around T_(m) is found to reach up to 11.85 J·kg^(-1)·K^(-1).Remarkably,both the antiferromagnetic transition temperature and-ln T behavior increase monotonically with pressure applied to 20 kbar(1 bar=10~5 Pa),indicating that much higher pressure will be needed to reach its quantum critical point. 展开更多
关键词 heavy fermion antiferromagnetic order magnetocaloric effect
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Association of age at diagnosis of diabetes with subsequent risk of age-related ocular diseases and vision acuity
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作者 Si-Ting Ye Xian-Wen Shang +8 位作者 yu huang Susan Zhu Zhuo-Ting Zhu Xue-Li Zhang Wei Wang Shu-Lin Tang Zong-yuan Ge Xiao-Hong Yang Ming-Guang He 《World Journal of Diabetes》 SCIE 2024年第4期697-711,共15页
BACKGROUND The importance of age on the development of ocular conditions has been reported by numerous studies.Diabetes may have different associations with different stages of ocular conditions,and the duration of di... BACKGROUND The importance of age on the development of ocular conditions has been reported by numerous studies.Diabetes may have different associations with different stages of ocular conditions,and the duration of diabetes may affect the development of diabetic eye disease.While there is a dose-response relationship between the age at diagnosis of diabetes and the risk of cardiovascular disease and mortality,whether the age at diagnosis of diabetes is associated with incident ocular conditions remains to be explored.It is unclear which types of diabetes are more predictive of ocular conditions.AIM To examine associations between the age of diabetes diagnosis and the incidence of cataract,glaucoma,age-related macular degeneration(AMD),and vision acuity.METHODS Our analysis was using the UK Biobank.The cohort included 8709 diabetic participants and 17418 controls for ocular condition analysis,and 6689 diabetic participants and 13378 controls for vision analysis.Ocular diseases were identified using inpatient records until January 2021.Vision acuity was assessed using a chart.RESULTS During a median follow-up of 11.0 years,3874,665,and 616 new cases of cataract,glaucoma,and AMD,respectively,were identified.A stronger association between diabetes and incident ocular conditions was observed where diabetes was diagnosed at a younger age.Individuals with type 2 diabetes(T2D)diagnosed at<45 years[HR(95%CI):2.71(1.49-4.93)],45-49 years[2.57(1.17-5.65)],50-54 years[1.85(1.13-3.04)],or 50-59 years of age[1.53(1.00-2.34)]had a higher risk of AMD independent of glycated haemoglobin.T2D diagnosed<45 years[HR(95%CI):2.18(1.71-2.79)],45-49 years[1.54(1.19-2.01)],50-54 years[1.60(1.31-1.96)],or 55-59 years of age[1.21(1.02-1.43)]was associated with an increased cataract risk.T2D diagnosed<45 years of age only was associated with an increased risk of glaucoma[HR(95%CI):1.76(1.00-3.12)].HRs(95%CIs)for AMD,cataract,and glaucoma associated with type 1 diabetes(T1D)were 4.12(1.99-8.53),2.95(2.17-4.02),and 2.40(1.09-5.31),respectively.In multivariable-adjusted analysis,individuals with T2D diagnosed<45 years of age[β95%CI:0.025(0.009,0.040)]had a larger increase in LogMAR.Theβ(95%CI)for LogMAR associated with T1D was 0.044(0.014,0.073).CONCLUSION The younger age at the diagnosis of diabetes is associated with a larger relative risk of incident ocular diseases and greater vision loss. 展开更多
关键词 DIABETES Age at diagnosis CATARACT GLAUCOMA Age-related macular disease Vision acuity
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Research on Sports Public Service Supply in the Chengdu-Chongqing Twin-City Economic Circle under the Background of Regional Economic Development
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作者 Yiming Yang yun Liu yu huang 《Proceedings of Business and Economic Studies》 2024年第2期106-113,共8页
Using literature,questionnaires,interviews,and mathematical statistics to investigate the current situation of sports public services in the Chengdu-Chongqing Twin-city Economic Circle.The results show that there are ... Using literature,questionnaires,interviews,and mathematical statistics to investigate the current situation of sports public services in the Chengdu-Chongqing Twin-city Economic Circle.The results show that there are some problems in Chengdu-Chongqing sports public services,such as big difference in the development level of supply between urban and rural areas,low supply level,low efficiency,supply mechanism defect,lack of social sports instructors,an outstanding contradiction between the quality of sports public service and residents’demand.To address the problems,government departments should accelerate the transformation of government functions,improve the relevant regulations and systems,increase the investment in sports public services,improve the quality of supply,cultivate the backbone team,integrate resources,and combine the national characteristics with regional characteristics,take into account the personalized needs of the residents,combine the sports public services with intelligence,and build the service system of“Internet+Fitness.” 展开更多
关键词 Regional economy Chengdu-Chongqing Twin-city Economic Circle Sports demand Sports public service Current supply situation
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Discussion on the Application of Technical and Tactical Skills in Mixed Martial Arts Competitions
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作者 yu huang 《Journal of Contemporary Educational Research》 2024年第2期8-13,共6页
This article mainly analyzes the application of technical and tactical skills in mixed martial arts competitions,including mixed martial arts and its competition characteristics,the main application significance of te... This article mainly analyzes the application of technical and tactical skills in mixed martial arts competitions,including mixed martial arts and its competition characteristics,the main application significance of technical and tactical skills in mixed martial arts competitions,and its primary application strategies.It is hoped that this analysis can provide some guidelines for the appropriate application of mixed martial arts athletes’technical and tactical skills to improve their winning rate in mixed martial arts competitions. 展开更多
关键词 Mixed martial arts competition Technical and tactical skills Fighting awareness Fighting movements Competition rhythm
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Current Research Status of Traditional Chinese Medicine External Treatment for Diarrhea Type Irritable Bowel Syndrome
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作者 Meihua Zhao yu huang 《Research and Inheritance of Traditional Chinese Medicine》 2024年第1期28-32,共5页
Irritable bowel syndrome(IBS-D)with diarrhea is a common gastrointestinal functional disease in clinical practice,which seriously affects the quality of life of patients.Cur‐rently,Western medicine has poor therapeut... Irritable bowel syndrome(IBS-D)with diarrhea is a common gastrointestinal functional disease in clinical practice,which seriously affects the quality of life of patients.Cur‐rently,Western medicine has poor therapeutic effects,while traditional Chinese medi‐cine has unique advantages in relieving IBS-D symptoms and preventing recurrence.In recent years,especially with external treatment of traditional Chinese medicine,it has become a new treatment direction in clinical practice and has achieved good therapeutic effects.This article will provide a review of recent research on the treatment of IBS-D using traditional Chinese medicine external treatment methods. 展开更多
关键词 diarrhea type irritable bowel syndrome traditional chinese medicine external treatment method summarize
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强脉冲光联合睑板腺按摩治疗MGD相关性干眼疗效的Meta分析 被引量:2
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作者 黄雨 李洁 +3 位作者 黎冬冬 孙嘉桧 夏鑫 彭清华 《国际眼科杂志》 CAS 北大核心 2023年第4期616-623,共8页
目的:评价强脉冲光(IPL)联合睑板腺按摩(MGX)治疗睑板腺功能障碍(MGD)相关性干眼(DED)的有效性。方法:检索中国期刊全文数据库(CNKI)、万方数据库、维普中文期刊数据库(VIP)、中国生物医学文献数据库(CBM)、ClinicalTrials、PubMed、Emb... 目的:评价强脉冲光(IPL)联合睑板腺按摩(MGX)治疗睑板腺功能障碍(MGD)相关性干眼(DED)的有效性。方法:检索中国期刊全文数据库(CNKI)、万方数据库、维普中文期刊数据库(VIP)、中国生物医学文献数据库(CBM)、ClinicalTrials、PubMed、Embase、Web of Science数据库,纳入2017-01/2022-09试验组采用IPL联合MGX,对照组单纯运用MGX治疗MGD相关性干眼的临床随机对照试验研究(RCTs)。采用Review Manager 5.3和Stata 14软件对临床疗效、眼表疾病指数(OSDI)评分、泪膜破裂时间(BUT)、角膜荧光素染色(CFS)评分、泪河高度(TMH)以及睑板腺分泌物性质评分(MGYSS)6个结局指标进行Meta分析。结果:最终纳入15篇RCTs,MGD相关性干眼患者1345例。Meta分析结果表明,与对照组相比,试验组治疗MGD相关性干眼可更好的提高临床疗效(OR=4.95,95%CI:2.76~8.90,Z=5.35,P<0.00001)、BUT(SMD=1.26,95%CI:0.84~1.69,Z=5.78,P<0.00001)、TMH(SMD=0.37,95%CI:0.15~0.59,Z=3.33,P=0.0009),降低OSDI评分(SMD=-0.86,95%CI:-1.44~-0.27,Z=2.85,P=0.004)以及MGYSS(SMD=-2.43,95%CI:-4.31~-0.54,Z=2.52,P=0.01)。但在CFS评分差异无统计学意义(SMD=-0.19,95%CI:-0.46~0.07,Z=1.43,P=0.15)。结论:IPL联合MGX治疗MGD相关性干眼与单纯运用MGX治疗相比,能提高总体有效率,更好地改善MGD相关性干眼患者的症状和体征。 展开更多
关键词 强脉冲光 睑板腺按摩 睑板腺功能障碍(MGD) 干眼 META分析
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花胶品质改良研究进展 被引量:2
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作者 谭忠发 陈鑫 +6 位作者 周晓满 余煌 杨沁萱 谷雅婷 张秋婷 卢永翎 吕丽爽 《食品安全质量检测学报》 CAS 北大核心 2023年第3期192-199,共8页
花胶是我国传统海产美食,属“四大海味”之一,近代列入“八珍”,具有很高的营养和药用价值。目前,花胶以传统的家庭或酒店烹饪预制菜为主,其加工产品较少,存在产品深加工程度低、原料综合利用差、废弃物造成环境污染等问题。花胶工业化... 花胶是我国传统海产美食,属“四大海味”之一,近代列入“八珍”,具有很高的营养和药用价值。目前,花胶以传统的家庭或酒店烹饪预制菜为主,其加工产品较少,存在产品深加工程度低、原料综合利用差、废弃物造成环境污染等问题。花胶工业化加工产品形式尚处于初级阶段,影响花胶加工产品深度开发的瓶颈问题尚未有相关研究报道。本文主要介绍了花胶的基本营养成分、花胶制品的主要产品形式、影响花胶品质的主要因素以及相关改良措施。主要包括:花胶产品的脱腥技术、凝胶特性和加工过程中热稳定性。本文从理论和实践技术方面对花胶品质的改良措施进行了深入探讨和概述,比较了各种方法的利弊,提出未来的发展方向,以期为今后开发出品质更加优良的花胶产品提供一定的理论支撑和研究思路。 展开更多
关键词 花胶 胶原蛋白 即食花胶 热稳定性 脱腥
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通过实验和理论验证Pt0/SrTiO_(3)-δ复合催化剂双反应路径促进CO_(2)还原
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作者 李卓根 Qadeer Ul Hassan +6 位作者 张伟斌 朱陆军 高健智 石先进 黄宇 刘鹏 朱刚强 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2023年第3期113-124,共12页
在以H_(2)O为质子源的光催化二氧化碳还原反应(CO_(2)RR)过程中,光解H_(2)O产氢气(H_(2))被认为是一个竞争反应.因此,光催化CO_(2)RR过程需要抑制H_(2)的产生,以提高碳氢产物的选择性和产率.以CO_(2)和H_(2)为反应物的逆水气变换反应(RW... 在以H_(2)O为质子源的光催化二氧化碳还原反应(CO_(2)RR)过程中,光解H_(2)O产氢气(H_(2))被认为是一个竞争反应.因此,光催化CO_(2)RR过程需要抑制H_(2)的产生,以提高碳氢产物的选择性和产率.以CO_(2)和H_(2)为反应物的逆水气变换反应(RWGS)是常见的CO_(2)加氢反应,在较高的温度和催化剂作用下生成CO和H_(2)O.目前,光催化CO_(2)RR研究主要聚焦于产物的选择性,而有关光解H_(2)O产生的还原性气体H_(2)在光热效应的促进下成为CO_(2)RR中新的质子源研究较少.光热催化是一种新的高效催化反应方式,在反应过程中需要光照和加热.光照能够促进半导体光生载流子的激发,热效应则能降低反应物分子的活化势垒,并能够促进中间产物的表面迁移以及生成物的脱附.利用光热催化热力学和动力学上的有利条件,为以H_(2)O为质子源的光热催化CO_(2)RR中RWGS反应提供了H_(2)源以及所需的能量.本文合成了具有强电子转移能力、高热稳定性和化学稳定性的Pt纳米颗粒(NPs)负载在具有丰富氧空位(OVs)的SrTiO_(3)-δ纳米片,形成金属-半导体相互作用的Pt-OVs-STO纳米复合催化剂,并利用该纳米复合催化剂系统地研究了以H_(2)O为质子源的光热催化CO_(2)RR的反应路径.结合X射线粉末衍射、X射线光电子能谱、高角度环形暗场和明场球差校正扫描电子显微镜、电子顺磁共振和紫外可见吸收光谱等表征手段,研究了表面负载的Pt^(0)NPs与SrTiO_(3)-δ之间的相互作用.这种金属-半导体之间的强相互作用和独特的电子结构促进了复合半导体结构的光吸收能力,提升了光生载流子的分离以及对反应物分子的吸附.由H_(2)O分解产生的H_(2)能够有效地促进在Pt-OVs-STO纳米复合结构的双路径CO_(2)还原反应:CO_(2)直接质子化和RWGS反应.DFT理论计算结果表明,该纳米复合结构能够有效地促进半导体表面电荷转移和H_(2)生成,并且降低RWGS反应和CO_(2)质子化的反应势垒.综上,本文阐明了在H_(2)O为质子源的光热催化CO_(2)RR中Pt^(0)/SrTiO_(3)-δ纳米复合结构上光解H_(2)O产生的H_(2)和RWGS反应之间的关系,并为后续的CO_(2)RR的研究提供了新视角. 展开更多
关键词 光热催化 析氢反应 逆水煤气反应 钙钛矿 金属-半导体相互作用
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铸造Cu−La−Zn合金的强化及导热行为
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作者 胡波 韩嘉璇 +6 位作者 李德江 于铭迪 王静雅 王雪杨 李子昕 黄彧 曾小勤 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2023年第9期2712-2725,共14页
开发一种适合于压铸的高导热Cu−La−Zn合金,该合金的导热系数高达200~300 W/(m·K),约为普通黄铜的两倍。分别定量研究铸态二元Cu−La(2.0%~4.5%La,质量分数)和三元Cu−2La−xZn(0~3.0%Zn,质量分数)合金中Cu6La金属间化合物和Zn固溶原... 开发一种适合于压铸的高导热Cu−La−Zn合金,该合金的导热系数高达200~300 W/(m·K),约为普通黄铜的两倍。分别定量研究铸态二元Cu−La(2.0%~4.5%La,质量分数)和三元Cu−2La−xZn(0~3.0%Zn,质量分数)合金中Cu6La金属间化合物和Zn固溶原子对强化和导热行为的影响。结果表明:每增加1%(质量分数)的La或Zn,合金导热系数下降约34 W/(m·K)。Cu−2La−xZn合金中α-Cu基体的晶格常数随Zn固溶原子的增加由3.6163Å增加到3.6239Å;在Zn原子的固溶强化作用下,α-Cu基体的硬度由1.495 GPa呈抛物线增加至1.597 GPa。根据基于显微组织的Maxwell−Eucken模型计算结果,确定Cu6La的导热系数约为35.37 W/(m·K);而每增加1%Zn(摩尔分数)的固溶原子,α-Cu基体的导热系数下降51.38 W/(m·K)。 展开更多
关键词 Cu−La−Zn合金 强化 导热系数 金属间化合物 固溶原子
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Simulation Analysis of Torsion Beam Hydroforming Based on the Fluid-Solid Coupling Method 被引量:1
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作者 yu huang Jian Li +2 位作者 Jiachun Yang Yongdong Peng Weixuan Zhang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2023年第1期139-156,共18页
Hydroformed parts are widely used in industrial automotive parts because of their higher stiffness and fatigue strength and reduced weight relative to their corresponding cast and welded parts.This paper reports a hyd... Hydroformed parts are widely used in industrial automotive parts because of their higher stiffness and fatigue strength and reduced weight relative to their corresponding cast and welded parts.This paper reports a hydraulicforming experimental platform for rectangular tube fittings that was constructed to conduct an experiment on the hydraulic forming of rectangular tube fittings.A finite element model was established on the basis of the fluid–solid coupling method and simulation analysis.The correctness of the simulation analysis and the feasibility of the fluid–solid coupling method for hydraulic forming simulation analysis were verified by comparing the experimental results with the simulation results.On the basis of the simulation analysis of the hydraulic process of the torsion beam using the fluid–solid coupling method,a sliding mold suitable for the hydroforming of torsion beams was designed for its structural characteristics.The effects of fluid characteristics,shaping pressure,axial feed rate,and friction coefficient on the wall thicknesses of torsions beams during formation were investigated.Fluid movement speed was related to tube deformation.Shaping pressure had a significant effect on rounded corners and straight edges.The axial feed speed was increased,and the uneven distribution of wall thicknesses was effectively improved.Although the friction coefficient had a nonsignificant effect on the wall thickness of the ladder-shaped region,it had a significant influence on a large deformation of wall thickness in the V-shaped area.In this paper,a method of fluid-solid coupling simulation analysis and sliding die is proposed to study the high pressure forming law in torsion beam. 展开更多
关键词 Fluid-solid coupling Hydraulic expansion Rectangular tube Torsional beam Wall thickness distribution
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高光谱结合极限学习机的玉米品种鉴别
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作者 张伏 王新月 +5 位作者 崔夏华 禹煌 曹炜桦 张亚坤 熊瑛 付三玲 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2023年第9期2928-2934,共7页
玉米是我国重要粮食作物之一,在我国广泛种植,筛选优良的玉米品种是农业生产和育种的关键,但市场上玉米品种繁多,如何快速准确高效鉴别玉米品种从而实现玉米高产高收亟待解决。提出了基于高光谱图像技术的极限学习机(ELM)鉴别模型,以期... 玉米是我国重要粮食作物之一,在我国广泛种植,筛选优良的玉米品种是农业生产和育种的关键,但市场上玉米品种繁多,如何快速准确高效鉴别玉米品种从而实现玉米高产高收亟待解决。提出了基于高光谱图像技术的极限学习机(ELM)鉴别模型,以期解决玉米品种鉴别问题。以八个品种玉米种子作为研究对象,试验样本共480个,按2∶1比例划分为训练集和测试集,分别为320个和160个。利用高光谱图像采集系统获取935.61~1720.23 nm范围内的玉米种子图像,黑白校正后选取胚芽部位大小为10×10 pixel的感兴趣区域(ROI),提取该区域内平均光谱作为原始光谱数据。因原始光谱两端噪声较大,有效信息较少,为增强信噪比,截取949~1700 nm范围内的玉米种子光谱波段作为有效波段进行分析。由于数据采集过程中受无关信息干扰较强影响建模效果,故对去噪后的光谱波段信息进行SG平滑(Savitzky-Golay smoothing)预处理,将平滑点数设置为3,在SG平滑基础上进行最大归一化(MN)预处理。预处理后分别采用竞争性自适应重加权算法(CARS)、连续投影算法(SPA)单一提取和CARS+SPA、CARS-SPA组合筛选方法提取特征波长,以特征波长反射率作为输入矩阵X,预设样本类别1、2、3、4、5、6、7、8作为输出矩阵Y,利用极限学习机分别建立(SG+MN)-ELM、(SG+MN)-CARS-ELM、(SG+MN)-SPA-ELM、(SG+MN)-(CARS+SPA)-ELM、(SG+MN)-(CARS-SPA)-ELM五种玉米品种定性鉴别模型。试验结果表明:(SG+MN)-(CARS-SPA)-ELM模型较其他四者鉴别效果最佳,训练集和测试集平均鉴别准确率均为98.13%,表明CARS-SPA二次筛选的特征波长变量更敏感,能够代表所有波长信息,且极限学习机模型有较好的定性鉴别性能,可实现对玉米品种的鉴别。该研究为玉米种子及其他农作物种子快速准确鉴别提供了新思路和新方法。 展开更多
关键词 高光谱图像技术 玉米 品种鉴别 极限学习机 组合筛选
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TRPV4在青光眼性视神经病变中的研究进展
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作者 黄雨 夏鑫 +1 位作者 周亚莎 彭清华 《国际眼科杂志》 CAS 北大核心 2023年第12期1973-1977,共5页
青光眼性视神经病变(GON)是青光眼治疗难点所在。近年来,关于GON的发病机制提出了多种学说,但其中任何一种均无法解释所有类型青光眼造成的视神经病变原理,使得该病在临床治疗中顾此失彼,且不利于早期干预。最新研究发现,存在于视网膜... 青光眼性视神经病变(GON)是青光眼治疗难点所在。近年来,关于GON的发病机制提出了多种学说,但其中任何一种均无法解释所有类型青光眼造成的视神经病变原理,使得该病在临床治疗中顾此失彼,且不利于早期干预。最新研究发现,存在于视网膜中的瞬时受体电位通道香草酸亚家族4(TRPV4)在GON多种发病机制中均占有重要地位。本文将对TRPV4及其在GON发生发展过程中所发挥的作用作一综述,以期为GON的多种机制学说寻找一共同“连接点”,这将有助于对该病的进一步认识和临床治疗。 展开更多
关键词 瞬时受体电位通道香草酸亚家族4(TRPV4) 青光眼性视神经病变 青光眼 视神经损伤 视神经病变
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调质态40NiCrMo7钢的高温性能
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作者 陈炜 于晃 +5 位作者 王思倩 牛丹 包翠敏 马国军 邹鹏 薛吉 《热处理》 CAS 2023年第3期9-11,17,共4页
对含0.389%C、0.807%Cr、1.715%Ni和0.237%Mo(质量分数)的40NiCrMo7钢进行了850℃油淬、590℃回火。热处理后,对钢在250~550℃进行了拉伸试验和在400~550℃以160~500 MPa的应力进行了低周次蠕变试验。研究了钢的线膨胀量、平均线膨胀系... 对含0.389%C、0.807%Cr、1.715%Ni和0.237%Mo(质量分数)的40NiCrMo7钢进行了850℃油淬、590℃回火。热处理后,对钢在250~550℃进行了拉伸试验和在400~550℃以160~500 MPa的应力进行了低周次蠕变试验。研究了钢的线膨胀量、平均线膨胀系数、高温拉伸性能和低周次高温蠕变性能随温度的变化。结果表明:随着温度从20℃升高至700℃,钢的线膨胀量先增大后减小再增大;随着温度从20℃开始升高,钢的平均线膨胀系数先增大后减小,在20~700℃钢的平均线膨胀系数最大;随着温度从250℃升高至350℃,钢的抗拉强度和屈服强度均下降,但塑性显示出相反的变化趋势;温度和应力对调质态40NiCrMo7钢的高温蠕变行为有显著影响,以相同应力在不同温度进行蠕变试验时,温度越高,蠕变越充分,而在相同温度以不同应力蠕变试验时,应力越大,蠕变越充分。 展开更多
关键词 调质 40NiCrMo7钢 线膨胀 高温拉伸性能 蠕变性能
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调质态SA320-L43钢的力学性能和显微组织研究
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作者 陈炜 于晃 +7 位作者 邵帅 郝建国 盖登宇 王思倩 牛丹 刘业超 王飞宇 邹鹏 《热处理》 CAS 2023年第2期50-52,共3页
对含0.41%C、0.79%Cr、1.79%Ni、0.28%Mo(质量分数)、尺寸为?150 mm×200 mm的SA320-L43钢锻坯进行了850℃保温3.5 h油淬然后于590℃回火6 h空冷的调质处理。随后检测了锻坯表面以下5 mm、1/2半径处和心部的力学性能和显微组织,并... 对含0.41%C、0.79%Cr、1.79%Ni、0.28%Mo(质量分数)、尺寸为?150 mm×200 mm的SA320-L43钢锻坯进行了850℃保温3.5 h油淬然后于590℃回火6 h空冷的调质处理。随后检测了锻坯表面以下5 mm、1/2半径处和心部的力学性能和显微组织,并通过材料性能模拟软件计算对检测结果进行了验证。结果表明:从锻坯近表面到心部,硬度均为278~295 HV5,强度稍有降低;近表面处的冲击韧度与1/2半径处的基本相同,略高于心部;从锻坯近表面到心部的显微组织均为回火索氏体;采用材料性能模拟软件计算的结果与检测结果比较吻合。 展开更多
关键词 SA320-L43钢 调质 力学性能 显微组织 模拟
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Analysis on Attenuation Efficiency of Lightning Current by Lightning Interceptor 被引量:1
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作者 Hui YANG Zhongqiu SHI +4 位作者 Renhong GUO Yixian QIU Qiaobin WEI Ruping ZHOU yu huang 《Meteorological and Environmental Research》 CAS 2023年第1期56-59,共4页
Lightning interception technology is one of the three core technical systems of regional lightning protection theory.Among them,the omni-directional multi-pulse lightning interceptor(hereinafter referred to as lightni... Lightning interception technology is one of the three core technical systems of regional lightning protection theory.Among them,the omni-directional multi-pulse lightning interceptor(hereinafter referred to as lightning interceptor,the same below)has the ability to attenuate lightning current≥40%and significantly reduce the intensity of the spatial electromagnetic field around the lightning point.In order to explore the attenuation mechanism and effect of lightning interceptor to lightning current,this paper analyzed a lightning stroke process at 16:00 on August 19,2022,and tried to explain the attenuation effect of lightning interceptor to lightning current with the physical parameters of lightning stroke. 展开更多
关键词 LIGHTNING INTERCEPTOR LIGHTNING CURRENT ATTENUATION efficiency Case ANALYSIS
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Distribution Characteristics and Shielding Effects of Ion Clouds 被引量:1
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作者 Hui YANG Zhongqiu SHI +3 位作者 Renhong GUO Yixian QIU Qiaobin WEI yu huang 《Meteorological and Environmental Research》 CAS 2023年第2期42-44,49,共4页
The latest research shows that the ions generated by the corona discharge of lightning rod have dual functions of attracting and shielding lightning discharge. After the lightning rod is installed at a certain height ... The latest research shows that the ions generated by the corona discharge of lightning rod have dual functions of attracting and shielding lightning discharge. After the lightning rod is installed at a certain height on the ground,the lightning rod tip reaches the corona threshold to ionize the surrounding air and generate positive and negative ions under the action of the electric field at the end of the lightning downward leader. Constrained by Coulomb’s Law,its positive ions( opposite charges attract each other) form an upward leader( streamer),which moves towards the end of the lightning downward leader and is connected to the downward leader,establishing a discharge channel to attract lightning to the needle tip and discharge the current to the ground,and playing a role in attracting lightning. Its negative ions are repelled by the electric field at the end of the lightning downward leader( repelled by isotropic charges) and influenced by the wind,and diffuse in the downwind area to form an ion cloud,inhibiting the growth of corona at the tip of ground objects,and playing a role in shielding lightning. In this paper,Franklin’s understanding of the role of lightning rod and Yang Shaojie’s new definition of the working principle of lightning rod are briefly introduced. The formation mechanism,distribution characteristics,shielding effect,and impact on lightning strike point distribution of ion clouds are analyzed. Additionally,the important role of shielding effects of ion clouds in regional lightning protection is introduced,which provides a theoretical basis for the correct understanding and use of lightning rod. 展开更多
关键词 Lightning rod Ion clouds Distribution characteristics Regional lightning protection Theoretical basis
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