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Species’ geographical range, environmental range and traits lead to specimen collection preference of dominant plant species of grasslands in Northern China

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Plant Diversity 2024年第3期46卷 353-361页

作者： Jingya Zhang cui xiao xiaoyu Duan Xin Gao Hao Zeng Rong'an Dong Gang Feng Keping Ma Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau&Inner Mongolia Key Laboratory of Grassland Ecology School of Ecology and EnvironmentInner Mongolia UniversityHohhot 010021China State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesBeijing 100093China

Many different factors,such as species traits,socio-economic factors,geographical and environmental factors,can lead to specimen collection preference.This study aims to determine whether grassland specimen collection in China is preferred by species traits(i.e.,plant height,flowering and fruiting period),environmental range(i.e.,the temperature and precipitation range)and geographical range(i.e.,distribution range and altitudinal range).Ordinary least squares models and phylogenetic generalized linear mixed models were used to analyze the relationships between specimen number and the explanatory variables.Random Forest models were then used to find the most parsimonious multivariate model.The results showed that interannual variation in specimen number between 1900 and 2020 was considerable.Specimen number of these species in southeast China was notably lower than that in northwest China.Environmental range and geographical range of species had significant positive correlations with specimen number.In addition,there were relatively weak but significant associations between specimen number and species trait(i.e.,plant height and flowering and fruiting period).Random Forest models indicated that distribution range was the most important variable,followed by flowering and fruiting period,and altitudinal range.These findings suggest that future floristic surveys should pay more attention to species with small geographical range,narrow environmental range,short plant height,and short flowering and fruiting period.The correction of specimen collection preference will also make the results of species distribution model,species evolution and other works based on specimen data more accurate.

关键词： Biological specimen Collection preference Dominant plant species Environmental range Geographical range Species traits

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Microstructural formation and mechanical performance of friction stir double-riveting welded Al-Cu joints

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Chinese Journal of Aeronautics 2023年第8期36卷 454-471页

作者： Shude JI Zhiqing ZHANG Peng GONG Hua LIU xiao cui Yewei ZHANG College of Aerospace Engineering Shenyang Aerospace UniversityShenyang 110136China

A novel friction stir double-riveting welding(FSDRW) technology was proposed in order to realize the high-quality joining of upper aluminum(Al) and lower copper(Cu) plates,and this technology employed a Cu column as a rivet and a specially designed welding tool with a large concave-angle shoulder. The formations, interfacial characteristics, mechanical properties and fracture features of Al/Cu FSDRW joints under different rotational velocities and dwell times were investigated. The results showed that the well-formed FSDRW joint was successfully obtained.The cylindrical Cu column was transformed into a double riveting heads structure with a Cu anchor at the top and an Al anchor at the bottom, thereby providing an excellent mechanical interlocking.The defect-free Cu/Cu interface was formed at the lap interface due to the sufficient metallurgical bonding between the Cu column and the Cu plate, thereby effectively inhibiting the propagation of crack from the intermetallic compound layer at the lap interface between the Al and Cu plates. The tensile shear load of joint was increased first and then decreased when the rotational velocity and dwell time of welding tool increased, and the maximum value was 5.52 k N. The FSDRW joint presented a mixed mode of ductile and brittle fractures.

关键词： Dissimilar Al/Cu metals Friction stir double-riveting welding,Mechanical interlocking Mechanical properties Metallurgical bonding

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Achieving High‑Quality Aluminum to Copper Dissimilar Metals Joint via Friction Stir Double‑Riveting Welding

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Acta Metallurgica Sinica(English Letters) 2023年第4期36卷 552-572页

作者： Shude Ji xiao cui Lin Ma Hua Liu Yingying Zuo Zhiqing Zhang College of Aerospace Engineering Shenyang Aerospace UniversityShenyang 110136China

In order to achieve a high-quality joining of aluminum(Al)and copper(Cu)dissimilar metals,a new friction stir doubleriveting welding(FSDRW)with a Cu rod as the rivet was proposed,and the rotating tool with a large concave angle shoulder was specially designed.The results showed that under the thermal–mechanical effect of rotating tool,the Cu rod was deformed to be a double riveting heads structure with a Cu anchor at the upper surface of Al plate and an Al anchor above the lap interface of joint,and these two anchors greatly enhanced the mechanical interlocking of Al/Cu joint.The effective bonding interfaces were formed among the double riveting heads structure,the upper Al plate and the lower Cu plate,which contained the Cu/Cu interface and the Al/Cu interface.The Cu/Cu interface without the kissing bond and the Al/Cu interface with the rationally thin AlCu and Al_(2)Cu intermetallic compounds(IMCs)layers were beneficial to heightening the joint tensile shear strength.The maximum tensile shear load of the FSDRW joint achieved 5.52 kN,and the joint under different plunging depths of rotating tool presented a mixed mode of ductile fracture and brittle fracture.This novel FSDRW technique owns the advantages of strong mechanical interlocking and superb metallurgical bonding,and provides a new approach to acquiring a high-quality Al/Cu dissimilar metals joint.

关键词： Al/Cu dissimilar metals joint Friction stir double-riveting welding Bonding interface Mechanical interlocking Tensile shear load

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Research on Interest Rate Transmission Mechanism of China’s Bond Market:Empirical Analysis Based on Granger Causality Complex Network

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Journal of Systems Science and Information 2023年第5期11卷 604-621页

作者： xiao cui Mo YIN Kun GUO Yijing WANG School of Economics and Management University of Chinese Academy of SciencesBeijing 100190China Research Center on Fictitious Economy&Data Science Chinese Academy of ScienceBeijing 100190China

The bond market is an important market for investment and financing in China’s economic sectors,and also an important part of the monetary policy framework.The internal transmission of bond market is an important part of market interest rate transmission,which iscritical to the effectiveness of monetary policy.However,few scholars have studied the characteristics of interest rate transmission in China.An in-depth study of the interest rate transmission mechanism and its dynamic evolution between different bond markets is conducive to clarify the pulse of transmission within Chinese bond market and to further unblock the transmission mechanism of monetary policy.From the perspective of system theory and based on the analysis method of Granger causality complex network,this paper finds that the interest rate transmission among various varieties in China’s bond market is relatively significant.Treasury bonds and CDB bonds are the two core bond varieties of interest rate transmission in the bond market.Simultaneously,this study concludes that the medium and long-term interest rate played a dominant role in the transmission of market interest rate during the easing phase of monetary policy,while the short-term interest rate played a dominant role in the transmission of market interest rate during the tightening phase of monetary policy.This paper also gives enlightenment and suggestions.

关键词： bond market interest rate transmission mechanism Granger causality complex network

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Unconventional photon blockade in the two-photon Jaynes–Cummings model with two-frequency cavity drivings and atom driving

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Chinese Physics B 2024年第2期33卷 164-168页

作者：刘欣田梦雨崔晓宁张馨鹤 School of Physics and Technology University of JinanJinan 250022China Marketing Service Center(Center of Metrology) State Grid ShanDong Electric Power CompanyJinan 250001China

In a two-frequency cavity driving and atom driving atom-cavity system,we find the photon blockade effect.In a truncated eigenstates space,we calculate the zero-delay second-order correlation function of the cavity mode analytically and obtain an optimal condition for the photon blockade.By including three transition pathways,we find that higher excitations of the cavity mode can be further suppressed and the zero-delay second-order correlation function can be reduced additionally.Based on the master equation,we simulate the system evolution and find that the analytical solutions match well with the numerical results.Our scheme is robust with small fluctuations of parameters and may be used as a new type of single photon source.

关键词： photon blockade single photon source quantum interference

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Flexible,stretchable,and transparent InGaN/GaN multiple quantum wells/polyacrylamide hydrogel-based light emitting diodes

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Nano Research 2022年第6期15卷 5492-5499页

作者： Jiwei Chen Jiangwen Wang Keyu Ji Bing Jiang xiao cui Wei Sha Bingjun Wang Xinhuan Dai Qilin Hua Lingyu Wan Weiguo Hu Center on Nanoenergy Research School of Physical Science and TechnologyGuangxi UniversityNanning 530004China CAS Center for Excellence in Nanoscience Beijing Key Laboratory of Micro-nano Energy and SensorBeijing Institute of Nanoenergy and NanosystemsChinese Academy of SciencesBeijing 100083China School of Nanoscience and Technology University of Chinese Academy of SciencesBeijing 100049China

Visualization is a direct,efficient,and simple interface method to realize the interaction between human and machine,whereas the flexible display unit,as the major bottleneck,still deeply hinders the advances of wearable and virtual reality devices.To obtain flexible optoelectronic devices,one of the effective methods is to transfer a high-efficient and long-lifetime inorganic optoelectronic film from its rigid epitaxial substrate to a foreign flexible/soft substrate.Additionally,piezo-phototronic effect is a fundamental theory for guiding the design of flexible optoelectronic devices.Herein,we demonstrate a flexible,stretchable,and transparent InGaN/GaN multiple quantum wells(MQWs)/polyacrylamide(PAAM)hydrogel-based light emitting diode coupling with the piezo-phototronic effect.The quantum well energy band and integrated luminous intensity(increased by more than 31.3%)are significantly modulated by external mechanical stimuli in the device.Benefiting from the small Young's modulus of hydrogel and weak Van der Waals force,the composite film can endure an extreme tensile condition of about 21.1%stretching with negligible tensile strains transmitted to the InGaN/GaN MQWs.And the stable photoluminescence characteristics can be observed.Moreover,the hydrogen-bond adsorption and excellent transparency of the hydrogel substrate greatly facilitate the packaging and luminescence of the optoelectronic device.And thus,such a novel integration scheme of inorganic semiconductor materials and organic hydrogel materials would help to guide the robust stretchable optoelectronic devices,and show great potential in emerging wearable devices and virtual reality applications.

关键词： InGaN/GaN multiple quantum wells hydrogel light emitting diode(LED) piezo-phototronic effect

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红外、拉曼光谱的变压器油中糠醛检测方法对比研究

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光谱学与光谱分析 2024年第1期44卷 125-133页

作者：李杰周渠贾路芬崔萧森西南大学工程技术学院重庆400715

变压器油中的糠醛含量是电力变压器中绝缘老化的重要指标之一,在物质有效识别上红外及拉曼光谱具有检测速度快、分析速率快及无损检测等优势,开展了基于红外、拉曼光谱的变压器油中糠醛检测方法对比,探究适用于变压器油中糠醛红外、拉... 详细信息

变压器油中的糠醛含量是电力变压器中绝缘老化的重要指标之一,在物质有效识别上红外及拉曼光谱具有检测速度快、分析速率快及无损检测等优势,开展了基于红外、拉曼光谱的变压器油中糠醛检测方法对比,探究适用于变压器油中糠醛红外、拉曼光谱的预处理及定量分析方法。基于傅里叶变换红外光谱仪和激光共聚焦拉曼光谱仪器对实验室配置的糠醛变压器油样检测并采集其光谱数据,采用小波变换、多项式最小二乘法和局部加权回归拟合对采集到的红外及拉曼光谱图进行预处理,综合考虑噪声、分辨率及有效信息丢失等,确定了多项式最小二乘法预处理效果最佳。基于高斯软件建立了糠醛分子模型,通过密度泛函仿真计算,研究了糠醛的红外及拉曼光谱吸收峰归属,结合实验测试光谱图,确定了变压器油中糠醛拉曼、红外检测特征峰分别为1 703和1 704 cm^(-1)。开展了红外及拉曼检测的重复性实验,两种检测方法的相对标准偏差分别为7.21%、 8.67%。通过绘制糠醛红外及拉曼的3D原位光谱图,分析红外及拉曼特征峰面积与不同糠醛浓度变压器油之间的关系,基于最小二乘法建立了变压器油中糠醛检测的红外及拉曼定量分析模型,拟合优度分别为0.998和0.885。对比两种检测方法的定量分析模型预测结果,表明拉曼光谱法检测下限低于红外光谱法,通过多项式最小二乘法预处理的光谱数据所构建的变压器油中糠醛检测红外及拉曼定量分析模型可以很好地预测变压器油中糠醛含量,为相关领域研究提供技术参考。

关键词：红外光谱拉曼光谱预处理变压器油糠醛

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Classification and microsurgical treatment of foramen magnum meningioma

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Chinese Neurosurgical Journal 2023年第2期9卷 114-126页

作者： Pengfei Wu Yanlei Guan Minghao Wang Luyang Zhang Dan Zhao xiao cui Jiyuan Liu Bo Qiu Jun Tao Yunjie Wang Shaowu Ou Department of Neurosurgery the First Affiliated HospitalChina Medical University155 Nanjing StreetHeping DistrictShenyang 110001LiaoningChina

Background To investigate the classification and microsurgical treatment of foramen magnum meningioma(FMM).Methods We retrospectively analyzed 76 patients with FMM and classified them into two classifications,classification ABS according to the relationship between the FMM and the brainstem and classification SIM according to the relationship between the FMM and the vertebral artery(VA).All patients underwent either the far lateral approach(54 cases)or the suboccipital midline approach(22 cases).Results Of the 76 cases,47 cases were located ahead of the brainstem(A),16 cases at the back of the brainstem(B),and 13 cases were located laterally to the brainstem(S).There were 15 cases located superior to the VA(S),49 cases were inferior(I),and 12 cases were mixed type(M).Among 76 cases,71 cases were resected with Simpson grade 2(93.42%),3 with Simpson grade 3(3.95%),and 2 with Simpson grade 4(2.63%).We summarized four anatomical triangles:triangles SOT,VOT,JVV,and TVV.The mean postoperative Karnofsky performance score was improved in all patients(p<0.05).However,several complications occurred,including hoarseness and CSF leak.Conclusion ABS and SIM classifications are objective indices for choosing the surgical approach and predicting the difficulty of FMMs,and it is of great importance to master the content,position relationship with the tumor,and variable anatomical structures in the four"triangles"for the success of the operation.

关键词： Classification Anatomical triangles Foramen magnum meningioma Microsurgical treatment Far lateral approach

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相识方式与婚姻稳定性——基于CFPS数据的事件史研究

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西北人口 2024年第3期45卷 117-126页

作者：钱佳崔晓楠华中师范大学教育学院武汉430079

中国离婚率的走高引起了社会各界的广泛关注,夫妻相识方式对婚姻稳定性的影响有待进一步探究。在当前自由恋爱式为主流的婚配背景下,学习和工作场域成为适婚个体在婚姻市场认识潜在对象最重要的两个场域,因此在学校或工作场所相识成为... 详细信息

中国离婚率的走高引起了社会各界的广泛关注,夫妻相识方式对婚姻稳定性的影响有待进一步探究。在当前自由恋爱式为主流的婚配背景下,学习和工作场域成为适婚个体在婚姻市场认识潜在对象最重要的两个场域,因此在学校或工作场所相识成为夫妻相识的主要方式。文章基于2010~2018年五期中国家庭追踪调查(CFPS)数据,采用事件史分析方法研究“学校相识”和“工作场所相识”两类相识方式对婚姻稳定性的影响。研究发现:(1)“学校相识”比“工作场所相识”的婚姻稳定性显著更高,前者的离婚风险约为后者的39.043%;(2)“工作场所相识”的离婚风险峰值出现更早,约在婚后7年,而“学校相识”的峰值出现在13年左右;(3)分教育程度看,高教育程度群体在“学校相识”比“工作场所相识”的婚姻稳定性更高,其中前者的离婚风险约为后者的45.611%,而低教育程度群体内不存在该差异;(4)分出生队列看,相识方式对婚姻稳定性的效用在不同出生队列组中均显著且比较稳健。在理论和实证分析基础上,文章呈现了夫妻不同相识方式对婚姻稳定性的影响,讨论集中于婚姻稳定性维度。然而,稳定的婚姻不一定是令人满意的、幸福的婚姻。因此,研究结论并不能代表“学校相识”或“工作场所相识”的婚姻幸福度,不应被视为鼓励寻求特定类别对象的证据。

关键词：相识方式婚姻稳定性离婚风险事件史分析

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多道次拉伸和感应电流处理5052铝合金的力学性能和显微组织演变

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Transactions of Nonferrous Metals Society of China 2024年第1期34卷 65-79页

作者：王世鹏崔晓辉肖昂余卓行杜志浩中南大学轻合金研究院长沙410083 中南大学机电工程学院长沙410083 中南大学高性能复杂制造国家重点实验室长沙410083

提出一种多道次拉伸和感应电流处理(IEPT)相结合的复合成形方法,采用TEM和EBSD揭示感应电流对材料显微组织和力学性能的影响规律。结果表明,采用4次拉伸5%和拉伸后放电,材料伸长率比原始材料增加145%。预拉伸试样经过IEPT处理后,强度下... 详细信息

提出一种多道次拉伸和感应电流处理(IEPT)相结合的复合成形方法,采用TEM和EBSD揭示感应电流对材料显微组织和力学性能的影响规律。结果表明,采用4次拉伸5%和拉伸后放电,材料伸长率比原始材料增加145%。预拉伸试样经过IEPT处理后,强度下降、塑性提高,材料的位错密度下降,晶粒变形结构向亚结构转变,同时晶粒尺寸略有增加。感应电流减弱材料的各向异性,出现新的//TD织构。电塑性效应和焦耳热效应的结合增强位错运动和空位移动。采用ANSYS软件模拟板料的温度分布,最高温度达到144.7℃。材料强度的理论计算结果与实验数据一致。

关键词： 5052铝合金感应电流织构演变焦耳热模拟强度计算

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