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Mechanical-electro-magnetic coupling in strained bilayer CrI3

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Science China(Technological Sciences) 2020年第7期63卷 1265-1271页

作者： zhang shuqing ZOU XiaoLong CHENG HuiMing Shenzhen Geim Graphene Center(SGC) Tsinghua-Berkeley Shenzhen Institute(TBSI)&Tsinghua Shenzhen International Graduate School(TSIGS)Tsinghua UniversityShenzhen 518055China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

The discovery of intrinsic 2D ferromagnets provides exciting possibilities for spintronics applications. A particularly attractive example is CrI3, whose monolayer is ferromagnetic while bilayer shows antiferromagnetic coupling. Because of weak interlayer coupling, the magnetism of bilayer CrI3 can be easily modulated by external perturbations, such as gating or pressure. Here, we constructed a magnetic phase diagram of bilayer CrI3 under arbitrary biaxial strain(within ±4%) from compression to stretch,and found that compressive strain can effectively convert the antiferromagnetic coupling of bilayer CrI3 to *** analyses on electronic structure were then performed to unravel the underlying mechanism of the magnetic phase transition. It was shown that both band gap and orbital composition at conduction band minimum play important roles in determining magnetic ground states of strained bilayer CrI3. These results strengthen our understanding of the interlayer magnetism of 2D magnets and provide a feasible way to modulate the magnetism in 2D layered materials.

关键词： bilayer Crl3 magnetic coupling strain band gap orbital composition

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平台企业数据垄断的影响及规制研究

金融教育研究 2024年第3期37卷 11-21页

作者：张莹张书晴杨慧珍山东财经大学公共管理学院山东济南250014

平台经济的蓬勃发展使数据升级为重要生产要素。囿于平台经济的固有特征、数据垄断的隐蔽性以及相关法律和监管漏洞,数据垄断问题日益凸显。对亚马逊和美团利用数据垄断违规获利的案例进行分析,发现数据垄断对市场会产生阻碍市场竞争、... 详细信息

平台经济的蓬勃发展使数据升级为重要生产要素。囿于平台经济的固有特征、数据垄断的隐蔽性以及相关法律和监管漏洞,数据垄断问题日益凸显。对亚马逊和美团利用数据垄断违规获利的案例进行分析,发现数据垄断对市场会产生阻碍市场竞争、实施自我优待、抑制市场创新的反竞争效应,导致消费者受到价格歧视、隐私泄露的负向影响。在根据案例分析启示和借鉴国内外关于数据垄断问题的治理经验基础上,从政府、平台企业、消费者三个层面提出平台企业数据垄断问题的规制策略。

关键词：平台企业数据垄断市场竞争消费者福利

Mechanical Fault Diagnosis Based on Band-phase-randomized Surrogate Data and Multifractal

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Chinese Journal of Mechanical Engineering 2011年第5期24卷 885-890页

作者： zhang shuqing ZHAO Yuchun zhang Liguo JIN Mei School of Electrical Engineering Yanshan University Qinhuangdao 066004 China

The vibration signals of machinery with various faults often show clear nonlinear ***,fractal dimension analysis as the common useful method for nonlinear signal analysis,is a kind of single fractal form,which only reflects the overall irregularity of signals,but cannot describe its local scaling *** comprehensive revealing of internal properties,a combinatorial method based on band-phase-randomized（BPR） surrogate data and multifractal is *** surrogate data method is effective to eliminate nonlinearity in specified frequency band for a fault signal,which can be utilized to detect nonlinear degree in whole fault signal by nonlinear titration method,and the overall nonlinear distribution of fault signal is displayed in nonlinear characteristic curve that can be used to analyze the fault signal *** multifractal theory as a quantitative analysis method is used to describe geometrical characteristics and local scaling properties,and asymmetry coefficient of multifractal spectrum and multifractal entropy for fault signals are extracted as new criterions to diagnose machinery *** typical faults include rotor misalignment,transversal crack,and static-dynamic rubbing fault are analyzed,and the results indicate that those faults can be distinguished by the proposed method effectively,which provides a qualitative and quantitative analysis way in the field of machinery fault diagnosis.

关键词： fault diagnosis band-phase-randomized surrogate data nonlinear titration multifractal

解磷菌与解磷固氮双效菌对贵州富硒土及茶苗硒锌含量的影响

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茶叶科学 2024年第3期44卷 431-442页

作者：张淑卿郭金梅李剑峰武玲王西曾正群贵州师范学院地理与资源学院贵州贵阳550018 贵州师范学院喀斯特生境土壤与环境生物修复研究所贵州贵阳550018 贵州省高等学校生物资源开发利用重点实验室贵州贵阳550018

为探究解磷菌及解磷固氮菌对富硒土壤及茶苗(Camelliasinensis)有效硒(Se)、有效锌(Zn)含量的影响,以2株茶树内生解磷菌(Paraburkholderia fungorum PSt07、Kluyvera intermediaPSt12)及2株茶树内生解磷固氮菌(Paraburkholderia fungorum PMS05、Kluyvera intermedia PCF06)为研究对象,以龙井43和黄金芽的2年生茶苗及贵州省开阳县的富硒红土为供试材料,进行土壤孵育及茶苗盆栽试验,检测接种各菌液60 d后,茶苗Se、Zn含量及土壤有效态的氮(N)、磷(P)、钾(K)、Zn、Se等养分。结果表明,供试菌株可提高两种茶苗根际土有效P含量,并提高龙井43茶树根际土有效N含量。两株解磷菌可提高龙井43根际土有效Se和有效Zn,以及根组织中Se含量,分别为191.83%~573.08%,37.48%~65.88%和24.27%~39.73%,并显著提高两种茶苗叶片的Zn积累量(41.23%~247.65%,P<0.05);两株解磷菌处理下盆栽植株根际土有效Zn含量高于以菌液孵育的土壤,表明茶株与解磷菌共同作用能显著提高土壤Zn有效性。解磷固氮双效菌较解磷菌更有利于提高黄金芽根组织Se含量及根际土的有效Se含量,其中PMS05可使黄金芽茶树根际土有效Se含量较未接菌显著增加602.00%(P<0.05)。Se、Zn在茶叶中的积累因菌株及茶树品种的不同组合而存在较大的差异,在实际应用中,应在菌种选育完成后以肥效验证试验为不同的茶树品种选择最优的解磷菌株。

关键词：解磷菌根际土壤硒锌茶树

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Multiple Time-scale Characteristics of Runoff Variations in Middle Reaches of Huolin River and Their Effects

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Chinese Geographical Science 2007年第2期17卷 143-150页

作者： LU Xiaoning DENG Wei zhang shuqing Northeast Institute of Geography and Agroecology Chinese Academy of Sciences Changchun 130012 China Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 China Graduate University of Chinese Academy of Sciences Beijing 100049 China Chengdu University of Information Technology Chengdu 620225 China

The Huolin River is one of the most important water sources for Xianghai wetland, Horqin wetland, and Chaganhu wetland in the western Songnen Plain of Northeast China. The annual runoff series of 46 years at Baiyunhushuo Hydrologic Station, which is located in the middle reaches of the Huolin River, were analyzed by using wavelet analysis. Main objective was to discuss the periodic characteristics of the runoff, and examine the temporal patterns of the Huolin River recharging to the floodplain wetlands in the lower reaches of the river, and the corresponding effects of recharging variation on the environmental evolution of the wetlands. The results show that the annual runoff varied mainly at three time scales. The intensities of periodical signals at different time scales were strongly characterized by local distribution in its time frequency domain. The interdecadal variation at a scale of more than 30yr played a leading role in the temporal pattern ofrnnoffvariation, and at this scale, the runoffat Baiyunhushuo Hydrologic Station varied in turn of flood, draught and flood. Accordingly, the landscape of the floodplain wetlands presented periodic features, especially prominent before the 1990s. Compared with intense human activities, the runoff periodic pattern at middle （10-20yr） and small （1-10yr） scales, which has relatively low energy, exerted unobvious effects on the environmental evolution of the floodplain wetlands, especially after the 1990s.

关键词： floodplain wetland runoff multiple time-scale wavelet analysis Huolin River

激光焊接7A52高强度铝合金焊缝气孔形成机理研究

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重庆交通大学学报（自然科学版） 2024年第3期43卷 128-134页

作者：苏菠陈大江张大斌胡江张淑清简汉青广西警察学院交通管理工程学院广西南宁530028 贵州大学机械工程学院贵州贵阳550025

为实现航空航天装备和汽车的结构轻量化,故使用厚度连续变化的7A52高强度铝合金板代替传统不锈钢等金属,从结构和材料密度两个角度实现轻量化。通过恒定功率的激光焊接铝合金变厚板时,单位体积内吸收的热量不同,匙孔演变产生气孔,影响... 详细信息

为实现航空航天装备和汽车的结构轻量化,故使用厚度连续变化的7A52高强度铝合金板代替传统不锈钢等金属,从结构和材料密度两个角度实现轻量化。通过恒定功率的激光焊接铝合金变厚板时,单位体积内吸收的热量不同,匙孔演变产生气孔,影响焊缝质量。焊缝内气孔主要由金属蒸气作用到匙孔壁,匙孔壁受力不均产生,为探究匙孔动态演变产生气孔的机理,提出将匙孔壁面的局部范围空间分为一定数量的小正方体块,计算相对较小范围内的能量和力,计算结果结合焊缝微观检测结果,分析力对匙孔壁面的作用。厚度小的一端焊缝充分熔透,匙孔壁面受到金属蒸气产生的压力和表面张力的不平衡作用,匙孔壁面局部范围形成气泡,厚度大的一端未熔透。铝合金焊缝凝固后,晶粒生长影响气泡的逃逸路径,气泡最后演变为气孔。

关键词：机电工程激光焊接焊缝铝合金匙孔

A New Method of Wind Turbine Bearing Fault Diagnosis Based on Multi-Masking Empirical Mode Decomposition and Fuzzy C-Means Clustering

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Chinese Journal of Mechanical Engineering 2019年第3期32卷 156-167页

作者： Yongtao Hu shuqing zhang Anqi Jiang Liguo zhang Wanlu Jiang Junfeng Li Institute of Electric Engineering Yanshan UniversityQinhuangdao 066004China School of Electrical Engineering and Automation Henan Institute of TechnologyXinxiang 453003China

Based on Multi-Masking Empirical Mode Decomposition (MMEMD) and fuzzy c-means (FCM) clustering, a new method of wind turbine bearing fault diagnosis FCM-MMEMD is proposed, which can determine the fault accurately and timely. First, FCM clustering is employed to classify the data into different clusters, which helps to estimate whether there is a fault and how many fault types there are. If fault signals exist, the fault vibration signals are then demodulated and decomposed into different frequency bands by MMEMD in order to be analyzed further. In order to overcome the mode mixing defect of empirical mode decomposition (EMD), a novel method called MMEMD is proposed. It is an improvement to masking empirical mode decomposition (MEMD). By adding multi-masking signals to the signals to be decomposed in different levels, it can restrain low-frequency components from mixing in highfrequency components effectively in the sifting process and then suppress the mode mixing. It has the advantages of easy implementation and strong ability of suppressing modal mixing. The fault type is determined by Hilbert envelope finally. The results of simulation signal decomposition showed the high performance of MMEMD. Experiments of bearing fault diagnosis in wind turbine bearing fault diagnosis proved the validity and high accuracy of the new method.

关键词： Wind turbine bearing faults diagnosis Multi-masking empirical mode decomposition (MMEMD) Fuzzy c-mean (FCM) clustering

Evolving Neural Network Using Variable String Genetic Algorithm for Color Infrared Aerial Image Classification

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Chinese Geographical Science 2008年第2期18卷 162-170页

作者： FU Xiaoyang P E R Dale zhang shuqing Institute of Computer and Science Technology Jilin University Zhuhai 519041 China Griffith Sehool of Environment Griffith University Queensland 4111 Australia Northeast Institute of Geography and Agroeeology Chinese Aeademy of Seienees Changehun 130012 China

Coastal wetlands are characterized by complex patterns both in their geomorphlc and ecological teatures. Besides field observations, it is necessary to analyze the land cover of wetlands through the color infrared （CIR） aerial photography or remote sensing image. In this paper, we designed an evolving neural network classifier using variable string genetic algorithm （VGA） for the land cover classification of CIR aerial image. With the VGA, the classifier that we designed is able to evolve automatically the appropriate number of hidden nodes for modeling the neural network topology optimally and to find a near-optimal set of connection weights globally. Then, with backpropagation algorithm （BP）, it can find the best connection weights. The VGA-BP classifier, which is derived from hybrid algorithms mentioned above, is demonstrated on CIR images classification effectively. Compared with standard classifiers, such as Bayes maximum-likelihood classifier, VGA classifier and BP-MLP （multi-layer perception） classifier, it has shown that the VGA-BP classifier can have better performance on highly resolution land cover classification.

关键词： variable string genetic algorithm neural network pattern classification CIR image

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芸薹根肿菌生理小种鉴定与检测方法研究进展

微生物学通报 2024年第9期51卷 3348-3371页

作者：余红瑞章艺张舒晴 HUSSAIN Iqbal 董正中雷娜门万杰余小林浙江大学蔬菜研究所浙江杭州310058 浙江大学新农村发展研究院浙江杭州310058 哈尔滨市农业科学院黑龙江哈尔滨150086

根肿病是由芸薹根肿菌(Plasmodiophora brassicae Woronin)引起的全球性土传病害,对十字花科芸薹属作物的产量和质量构成了严重的威胁。根肿菌为专性活体寄生菌,具有强烈的生理小种分化现象,因此,对不同地区的生理小种类型进行评估,有... 详细信息

根肿病是由芸薹根肿菌(Plasmodiophora brassicae Woronin)引起的全球性土传病害,对十字花科芸薹属作物的产量和质量构成了严重的威胁。根肿菌为专性活体寄生菌,具有强烈的生理小种分化现象,因此,对不同地区的生理小种类型进行评估,有利于芸薹属作物的抗性育种及作物栽培的整体规划。精确评估土壤中芸薹根肿菌休眠孢子的数量,有助于准确预测田块中根肿病发生的风险水平,可为后续防治方法的选择和防治效果的评估奠定基础。本文对芸薹根肿菌生理小种的鉴定以及土壤中根肿菌休眠孢子的检测和定量方法进行了简要综述,同时提出了一种有望应用于根肿菌生理小种研究的单细胞测序技术,并对重组酶聚合酶扩增技术(recombinase polymerase amplification,RPA)在根肿菌检测与定量方面的可行性进行了分析。本文旨在为根肿病的高效防控提供理论依据和方法参考,同时为根肿菌鉴定与检测方法的研究提供新的研究思路和解决方案。

关键词：根肿病芸薹根肿菌生理小种根肿病鉴别系统定量方法