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Compressive behavior and deformation kinetics of ultrafine grained aluminum processed by equal channel angular pressing

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International Journal of Smart and Nano Materials 2017年第1期8卷 56-77页

作者： Jin Su zhong-bin tang Cun-xian Wang Tian Ye Tao Suo Yu-long Li School of Aeronautics Northwestern Polytechnical UniversityXi‘anChina Fundamental Science on Aircraft Structural Mechanics and Strength Laboratory Northwestern Polytechnical UniversityXi’anChina

In the present work,the uniaxial compressive mechanical proper\ties of ultrafine grained(UFG)aluminum produced by equal channel angular pressing method were investigated experimentally over a wide temperatures ranging from 77 to 473 K under both quasi-static and dynamic loading *** on the experimental results,the strain rate,temperature sensitivity,and the apparent activation volume were *** coupling effects of both experimental temperature and applied strain rate on thermal-activated plastic deformation behavior were also *** on the thermal activation theory,the rate-controlling mechanisms for the UFG aluminum under both quasi-static and dynamic loading conditions were discussed.

关键词： Ultrafine-grained aluminum mechanical behavior strain rate sensitivity temperature sensitivity rate-controlling mechanism

CIPs@Mn_(0.8)Zn_(0.2)Fe_(2)O_(4)-CNTs复合材料低频吸波性能研究

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无机材料学报 2024年第1期39卷 71-80,I0003,I0004页

作者：陈海燕唐志鹏尹良君张林博徐鑫电子科技大学电子科学与工程学院国家电磁辐射控制材料工程技术中心多频谱吸波材料与结构教育部重点实验室成都611731 中国科学技术大学材料科学与工程系能量转换材料重点实验室合肥230026

随着5G无线通信与低频雷达侦察技术的飞速发展,低频电磁波辐射已成为当代的严重问题。目前,中高频段吸波材料的研究已趋于成熟,而设计低频段吸波材料仍面临巨大的挑战,亟待研究者们解决。基于四分之一波长相消机制,本研究设计了0.5~3 GH... 详细信息

随着5G无线通信与低频雷达侦察技术的飞速发展,低频电磁波辐射已成为当代的严重问题。目前,中高频段吸波材料的研究已趋于成熟,而设计低频段吸波材料仍面临巨大的挑战,亟待研究者们解决。基于四分之一波长相消机制,本研究设计了0.5~3 GHz低频段复合吸波材料。采用简单的一步水热法,诱导铁氧体在羰基铁粉与碳纳米管表面生长,制备出CIPs@Mn_(0.8)Zn_(0.2)Fe_(2)O_(4)-CNTs三元复合材料,对比研究了碳纳米管含量对材料吸收峰频率的影响。实验结果表明,引入碳纳米管,一方面为材料带来了界面极化、偶极极化等额外的损耗机制,增加了材料的衰减系数;另一方面基于四分之一波长相消机制,高介电与高磁导率的耦合,使材料在低频段获得良好的阻抗匹配。最终,在4 mm厚度下,样品分别在2.11与1.75 GHz处,获得了–40.8与–32.1 dB的反射损耗,–10 dB带宽分别为1.70~2.70 GHz和1.40~2.20 GHz。该复合材料制备工艺简单,低频吸收性能良好,具有很大的应用潜力,为开发更有效的低频吸波材料提供了新的思路和方法。

关键词：碳纳米管复合材料羰基铁粉波长相消低频吸波

马关县不同品种多花黑麦草产量及营养成分分析

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中国奶牛 2024年第10期 63-67页

作者：邹曼徐佳祥唐连英毛华明李琦华鲁琼芬云南农业大学动物科学技术学院昆明650201 云南省动物营养与饲料重点实验室昆明650201

本研究旨在比较不同品种多花黑麦草在马关县种植的产量及营养成分,筛选优良品种以满足当地肉牛养殖基地对牧草的需求。选取大老板、阿德纳、钻石T和特高4个多花黑麦草品种进行种植试验,待牧草生长到灌浆后、夏播前确保大部分叶片为绿色... 详细信息

本研究旨在比较不同品种多花黑麦草在马关县种植的产量及营养成分,筛选优良品种以满足当地肉牛养殖基地对牧草的需求。选取大老板、阿德纳、钻石T和特高4个多花黑麦草品种进行种植试验,待牧草生长到灌浆后、夏播前确保大部分叶片为绿色时刈割测产,并采样进行营养成分分析。结果表明,大老板干产显著高于阿德纳(P<0.05);特高粗蛋白产量和增重净能(NEg)均显著高于阿德纳和大老板(P<0.05);各品种间干物质(DM)含量呈显著性差异(P<0.05);钻石T粗脂肪(EE)含量显著高于大老板(P<0.05);特高粗灰分(Ash)含量显著高于大老板、钻石T和阿德纳(P<0.05);特高粗蛋白(CP)、磷(P)、中性洗涤不溶蛋白(NDICP)含量均显著高于其他品种(P<0.05);大老板、阿德纳、钻石T三者的钙(Ca)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)、酸性洗涤不溶蛋白(ADICP)、木质素(ADL)、酸性不溶灰分(AIA)含量均显著高于特高(P<0.05)。本试验4个多花黑麦草品种的消化能(DE)在2.69~3.08Mcal/kg之间,代谢能(ME)在2.26~2.67Mcal/kg之间,维持净能(NEm)在1.40~1.75Mcal/kg之间,增重净能(NEg)在0.81~1.13Mcal/kg之间。结果发现,以亩产量、营养成分和能量为综合评价指标,适合在马关县种植的多花黑麦草品种为特高,其次为钻石T。

关键词：多花黑麦草产量营养成分能量

母亲基于儿童的价值及其侵入性教养与学前儿童执行功能的关系:儿童性别的调节作用

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心理与行为研究 2024年第2期22卷 243-250页

作者：唐楚涵邢淑芬李玉华首都师范大学心理学院北京100048 首都师范大学初等教育学院北京100048

采用方便取样的方法选取河北省和山东省的319名学前儿童及其母亲为研究对象,考察母亲基于儿童的价值是否通过其侵入性教养影响学前儿童执行功能子成分以及性别特异性。结果发现:(1)母亲基于儿童的价值显著正向预测其侵入性教养;(2)母亲... 详细信息

采用方便取样的方法选取河北省和山东省的319名学前儿童及其母亲为研究对象,考察母亲基于儿童的价值是否通过其侵入性教养影响学前儿童执行功能子成分以及性别特异性。结果发现:(1)母亲基于儿童的价值显著正向预测其侵入性教养;(2)母亲侵入性教养在母亲基于儿童的价值与学前儿童抑制控制、认知灵活性之间起中介作用;(3)儿童性别仅在母亲侵入性教养到学前儿童抑制控制的路径上具有调节作用,且仅在学前女孩的抑制控制上达到显著水平。本研究从母亲基于儿童的价值的角度出发,探讨了母亲侵入性教养的潜在原因,并为促进儿童认知发展提供了养育建议和指导。

关键词：学前儿童基于儿童的价值侵入性教养执行功能

地理大数据揭示中国主要城市建成环境物质存量的空间格局

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Engineering 2024年第3期34卷 143-153页

作者： Zhou huang Yi Bao Ruichang Mao Han Wang Ganmin Yin Lin Wan Houji Qi Qiaoxuan Li Hongzhao tang Qiance Liu Linna Li Bailang Yu Qinghua Guo Yu Liu huadong Guo Gang Liu Institute of Remote Sensing and Geographical Information Systems School of Earth and Space SciencesPeking UniversityBeijing 100871China International Research Center of Big Data for Sustainable Development Goals Beijing 100094China SDU Life Cycle Engineering Department of Green TechnologyUniversity of Southern DenmarkOdense 5230Denmark Department of Construction Management School of Civil EngineeringTsinghua UniversityBeijing 100084China School of Computer Science China University of GeosciencesWuhan 430074China School of Geographical Sciences East China Normal UniversityShanghai 200062China Land Satellite Remote Sensing Application Center Ministry of Natural ResourcesBeijing 100048China Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China Department of Geography California State UniversityLong BeachCA 90840USA Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China College of Urban and Environmental Sciences Peking UniversityBeijing 100871China

The patterns of material accumulation in buildings and infrastructure accompanied by rapid urbanization offer an important,yet hitherto largely missing stock perspective for facilitating urban system engineering and informing urban resources,waste,and climate ***,our existing knowledge on the patterns of built environment stocks across and particularly within cities is limited,largely owing to the lack of sufficient high spatial resolution *** study leveraged multi-source big geodata,machine learning,and bottom-up stock accounting to characterize the built environment stocks of 50 cities in China at 500 m fine-grained *** per capita built environment stock of many cities(261 tonnes per capita on average)is close to that in western cities,despite considerable disparities across cities owing to their varying socioeconomic,geomorphology,and urban form *** is mainly owing to the construction boom and the building and infrastructure-driven economy of China in the past ***’s urban expansion tends to be more“vertical”(with high-rise buildings)than“horizontal”(with expanded road networks).It trades skylines for space,and reflects a concentration-dispersion-concentration pathway for spatialized built environment stocks development within cities in *** results shed light on future urbanization in developing cities,inform spatial planning,and support circular and low-carbon transitions in cities.

关键词： Urban system engineering Built environment stock Spatial pattern Urban sustainability Big geodata

Genetic analysis of transcription factors in dopaminergic neuronal development in Parkinson’s disease

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Chinese Medical Journal 2024年第4期137卷 450-456页

作者： Yuwen Zhao Lixia Qin Hongxu Pan Tingwei Song Yige Wang Xiaoxia Zhou Yaqin Xiang Jinchen Li Zhenhua Liu Qiying Sun Jifeng Guo Xinxiang Yan Beisha tang Qian Xu Department of Neurology Xiangya HospitalCentral South UniversityChangshaHunan 410008China Department of Neurology The Second Xiangya HospitalCentral South UniversityChangshaHunan 410011China Bioinformatics Center National Clinical Research Center for Geriatric Disorders Xiangya HospitalCentral South UniversityChangshaHunan 410008China Department of Geriatrics Xiangya HospitalCentral South UniversityChangshaHunan 410008China Centre for Medical Genetics and Hunan Key Laboratory of Medical Genetics School of Life SciencesCentral South UniversityChangshaHunan 410008China Key Laboratory of Hunan Province in Neurodegenerative Disorders Central South UniversityChangshaHunan 410008China

Background:Genetic variants of dopaminergic transcription factor-encoding genes are suggested to be Parkinson’s disease(PD)risk factors;however,no comprehensive analyses of these genes in patients with PD have been ***,we aimed to genetically analyze 16 dopaminergic transcription factor genes in Chinese patients with ***:Whole-exome sequencing(WES)was performed using a Chinese cohort comprising 1917 unrelated patients with familial or sporadic early-onset PD and 1652 ***,whole-genome sequencing(WGS)was performed using another Chinese cohort comprising 1962 unrelated patients with sporadic late-onset PD and 1279 ***:We detected 308 rare and 208 rare protein-altering variants in the WES and WGS cohorts,***-based association analyses of rare variants suggested that MSX1 is enriched in sporadic late-onset ***,the significance did not pass the Bonferroni ***,72 and 1730 common variants were found in the WES and WGS cohorts,***,single-variant logistic association analyses did not identify significant associations between common variants and ***:Variants of 16 typical dopaminergic transcription factors might not be major genetic risk factors for PD in Chinese ***,we highlight the complexity of PD and the need for extensive research elucidating its etiology.

关键词： Parkinson’s disease Transcription factors Dopaminergic neurons Genetic Variants

Rectifying the Current−Voltage Characteristics of a LiNbO3 Film/GaN Heterojunction

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Chinese Physics Letters 2011年第10期28卷 240-243页

作者： HAO Lan-zhong LIU Yun-Jie ZHU Jun LEI hua-Wei LIU Ying-Ying tang Zheng-Yu ZHANG Ying ZHANG Wan-Li LI Yan-Rong State Key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of ChinaChengdu 610054 Faculty of Science China University of PetroleumQingdao 266555

Epitaxial LiNbO_(3)(LNO)films are grown on n−type GaN semiconductor substrates,forming LNO/GaN p-n *** current-voltage(I–V)and capacitance−voltage(C–V)characteristics of the junctions are *** I–V curve shows a clear rectifying property with a turn−on voltage of 2.4 *** the forward voltages,the conduction mechanism transits from Schottky thermionic emission for low voltages to space-charge-limited current for large *** C–V characteristics exhibit a linear 1/C2 versus V plot,from which a built-in potential of 0.34 V is *** results are explained using the energy-band structure of the LNO/GaN junction.

关键词： GaN Schottky capacitance

Zr^(4+)共掺对Cs_(2)LaLiBr_(6):Ce晶体的中子/伽马甄别性能的影响

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无机材料学报 2024年第5期39卷 539-546页

作者：郑中秋魏钦华童宇枫唐高尹航秦来顺中国计量大学材料与化学学院杭州310018 中国科学院上海硅酸盐研究所人工晶体研究中心上海201899

中子探测技术广泛用于国土安全、核材料安全检测以及高能物理等领域,由于3He资源紧缺,近年来急需开发出能够同时甄别中子/伽马的新型闪烁晶体,Cs_(2)LaLiBr_(6):Ce(CLLB:Ce)晶体具有良好的中子/伽马甄别能力、优异的能量分辨率以及高的... 详细信息

中子探测技术广泛用于国土安全、核材料安全检测以及高能物理等领域,由于3He资源紧缺,近年来急需开发出能够同时甄别中子/伽马的新型闪烁晶体,Cs_(2)LaLiBr_(6):Ce(CLLB:Ce)晶体具有良好的中子/伽马甄别能力、优异的能量分辨率以及高的光输出,但其中子/伽马甄别性能有待进一步提高。本研究采用垂直布里奇曼法成功生长了Zr^(4+)共掺杂的CLLB:Ce晶体。通过不同表征手段研究了Zr^(4+)共掺杂CLLB:Ce晶体的结构和组分,结果表明Zr^(4+)成功掺入基质材料且对基质晶体结构不产生明显的影响,Zr^(4+)共掺杂后没有产生新的发光中心,紫外衰减时间约为27.0 ns,仍具有较快的荧光衰减。Zr^(4+)共掺杂CLLB:Ce晶体的品质因子(Figure of Merit,FOM)从1.2提高到1.5,表明其中子/伽马甄别能力得到改善。结合热稳定性和闪烁衰减时间,探讨了衰减时间对FOM的影响机制,Zr^(4+)共掺杂可以抑制浅电子陷阱和Vk中心,减少电子捕获和脱陷过程,使Ce^(3+)直接捕获的概率大大增加,从而表现出更快的衰减速率。本研究显示,Zr^(4+)共掺杂CLLB:Ce晶体在中子/伽马探测领域具有潜在的应用前景。

关键词：闪烁晶体 CLLB:Ce 中子/伽马甄别钾冰晶石结构

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MRI探索儿童斜坡开始黄髓化的年龄界值

磁共振成像 2024年第8期15卷 97-102页

作者：唐琼梅黄勤鹏胡石腾郴州市第一人民医院放射科郴州423000

目的通过分析儿童正常斜坡的MRI特点,探索儿童斜坡开始黄髓化的年龄界值,以利于更好地识别骨髓病变。材料与方法选取2022年4月至2023年10月在本院放射科行颅脑MRI检查的儿童作为研究对象,通过分析2141例儿童正常斜坡信号特点与年龄分布... 详细信息

目的通过分析儿童正常斜坡的MRI特点,探索儿童斜坡开始黄髓化的年龄界值,以利于更好地识别骨髓病变。材料与方法选取2022年4月至2023年10月在本院放射科行颅脑MRI检查的儿童作为研究对象,通过分析2141例儿童正常斜坡信号特点与年龄分布的关系,探讨儿童斜坡开始黄髓化的年龄界限。在T1WI序列正中矢状面观察斜坡的信号特点,分析未黄髓化及黄髓化年龄分布特点,计算Youden指数及绘制年龄预测斜坡黄髓化的受试者工作特征(receiver-operating chatacteristic,ROC)曲线,探索儿童斜坡开始黄髓化的年龄界值。结果2141例儿童中,男孩1339例,女孩802例。1339例男孩中,未黄髓化者521例(1个月~36个月),黄髓化者818例(4个月~180个月);802例女孩中,未黄髓化者326例(1个月~35个月),黄髓化者476例(5个月~201个月)。男孩年龄为13.5个月时,Youden指数为0.814,ROC曲线下面积(area under the curve,AUC)为0.976,95%置信区间(confidence interval,CI):0.969~0.982;女孩年龄为11.5个月时,Youden指数0.836,AUC为0.980,95%CI:0.973~0.987。结论年龄>13.5个月可作为男孩斜坡开始黄髓化的年龄界值;年龄>11.5个月可作为女孩斜坡开始黄髓化的年龄界值;男孩开始黄髓化的年龄晚于女孩。

关键词：儿童斜坡黄髓化磁共振成像年龄界值