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Applied Mathematics and Mechanics(English Edition) 2019年第8期40卷 1053-1082页

作者： Jin ZENG hui MA Kun yu Zhitao XU Bangchun WEN School of Mechanical Engineering and Automation Northeastern University Shenyang 110819China Key Laboratory of Vibration and Control of Aero-Propulsion System Ministry of Education Northeastern UniversityShenyang 110819China

A rotating pre-twisted and inclined cantilever beam model (RPICBM) with the flapwise-chordwise-axial-torsional coupling is established with the Hamilton principle and the finite element (FE) method. The effectiveness of the model is verified via comparisons with the literatures and the FE models in ANSYS. The effects of the setting and pre-twisted angles on the dynamic responses of the RPICBM are analyzed. The results show that:(i) the increase in the setting or pre-twisted angle results in the increases in the first-order flapwise and torsional frequencies while the decrease in the first-order chordwise frequency under rotating conditions;(ii) a positive/negative setting angle leads to a positive/negative constant component, while a positive/negative pre-twisted angle leads to a negative/positive constant component;(iii) when the rotation speed is non-zero, the pre-twisted angle or non-zero setting angle will result in the coupled flapwise-chordwiseaxial- torsional vibration of the RPICBM under axial base excitation.

关键词： modal characteristic vibration response flapwise-chordwise-axial-torsional base excitation rotating Timoshenko beam

基于骨架序列多算法的粮仓作业人员异常行为视频识别

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粮油食品科技 2024年第3期32卷 201-210页

作者：侯晓龙杨卫东李磊于俊伟许启铿河南工业大学信息科学与工程学院河南郑州450001 河南工业大学人工智能与大数据学院河南郑州450001 河南工业大学土木工程学院河南郑州450001

粮仓是保障粮食储藏安全的重要设施。粮仓为封闭大空间,仓内光照昏暗、空气流通差,熏蒸、气调等作业增加了人员安全隐患,通过仓内安防视频对作业人员的异常行为进行识别与分析,是作业人员安全操作的一项重要技术保障。提出了一种基于骨... 详细信息

粮仓是保障粮食储藏安全的重要设施。粮仓为封闭大空间,仓内光照昏暗、空气流通差,熏蒸、气调等作业增加了人员安全隐患,通过仓内安防视频对作业人员的异常行为进行识别与分析,是作业人员安全操作的一项重要技术保障。提出了一种基于骨架序列多算法的粮仓内作业人员异常行为的视频识别算法。首先,利用YOLOv3tiny模型对人体进行快速检测,结合Sort对多目标进行运动轨迹跟踪,通过AlphaPose模型提取人体骨架坐标序列及权重信息;进而,根据人体骨架自然连接节点构成的实际空间图(RSG)和虚拟人体的重心与头、手、脚互连构建的虚拟空间图(VSG),基于人体动力学重心与手脚互动的平衡性,提取仓内作业人员异常行为的空间特征和串联时间卷积(TC)的时空特征;最后,提出了虚实结合的时空图卷积网络(VR-STGCN)仓内作业人员的异常行为视频识别算法。同时自建了混合数据集,并将VR-STGCN与SSD、PCANet、Two-StreamCNN、STGCN等四种算法进行了对比实验与分析。结果表明:VR-STGCN各项指标均优于其他四种算法;VR-STGCN能够在光线不足、多目标、远距离等复杂环境下准确地识别出仓内人员的跌倒、爬行、躺平等异常行为,识别准确率达到97.7%,处理速度为18.67 fps,能够实时分析作业人员异常行为。研究成果为复杂环境下粮仓作业人员的安全保障提供了一种全新高效的技术。

关键词：时空图卷积异常行为识别人体动力学粮仓作业安全

A Ten-year Retrospective Study of Invasive Candidiasis in a Tertiary Hospital in Beijing

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Biomedical and Environmental Sciences 2021年第10期34卷 773-788页

作者： YANG Zhi hui SONG Ying Gai LI Ruo yu Department of Dermatology and Venerology Beijing Key Laboratory of Molecular Diagnosis of DermatosesNational Clinical Research Center for Skin and Immune DiseasesNMPA Key Laboratory for Quality Control and Evaluation of CosmeticsPeking University First HospitalBeijing 100034China

Objective This study aimed to evaluate the epidemiological,clinical and mycological characteristics of invasive candidiasis(IC)in *** A ten-year retrospective study including 183 IC episodes was conducted in a tertiary hospital in Beijing,*** The overall incidence of IC from 2010–2019 was 0.261 episodes per 1,000 ***(71.0%)was the major infective pattern;70.3%of the patients tested positive for Candida *** before IC and the median time to develop an invasive infection after colonization was13.5 days(interquartile range:4.5–37.0 days).Candida albicans(45.8%)was the most prevalent species,followed by Candida parapsilosis(19.5%),Candida glabrata(14.2%)and Candida tropicalis(13.7%).***-albicans IC was more common in patients with severe anemia(P=0.018),long-term hospitalization(P=0.015),hematologic malignancies(P=0.002),continuous administration of broad-spectrum antibiotics(P<0.001)and mechanical ventilation(P=0.012).In vitro resistance testing showed that11.0%of the Candida isolates were resistant/non-wild type(non-WT)to fluconazole,followed by voriconazole(9.6%),micafungin(3.8%),and caspofungin(2.9%).Fluconazole was the most commonly used drug to initiate antifungal therapy both before and after the proven diagnosis(52.6%and 54.6%,respectively).The 30-day and 90-day all-cause mortality rates were 24.5%and 32.7%,*** The incidence of IC has declined in the recent five ***-albicans contributed to more than half of the IC *** can be used as first-line therapy if resistant strains are not ***,multi-center surveillance of the clinical and mycological characteristics of IC is required.

关键词： Invasive candidiasis Epidemiology Risk factors Antifungal resistance Treatment Mortality

阿特拉津海水水质基准及在莱州湾的生态风险评估研究

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中国海洋大学学报（自然科学版） 2024年第9期54卷 78-87页

作者：王辉隋傅高晨秦璐赵玲超宋秀凯汝少国王军中国海洋大学海洋生命学院山东青岛266003 山东省海洋资源与环境研究院山东省海洋生态修复重点实验室山东烟台264006

针对近海常见污染物阿特拉津水质基准缺失的问题,本研究搜集了阿特拉津对海洋生物的毒性数据,获得急性毒性数据76个,涵盖10门34科,共38个物种,其中,绿藻门扁藻(Tetraselmis chuii)和褐藻门鼓藻(Bellerochea polymorpha)的种平均急性毒... 详细信息

针对近海常见污染物阿特拉津水质基准缺失的问题,本研究搜集了阿特拉津对海洋生物的毒性数据,获得急性毒性数据76个,涵盖10门34科,共38个物种,其中,绿藻门扁藻(Tetraselmis chuii)和褐藻门鼓藻(Bellerochea polymorpha)的种平均急性毒性值为0.02 mg/L,对阿特拉津最为敏感;得到慢性毒性数据32个,涵盖10门18科,共19个物种,其中褐藻门舟形藻(Navicula sp.)的种平均慢性毒性值为0.0043 mg/L,对阿特拉津最敏感。基于收集的急、慢性毒性数据,利用物种敏感度分布(Species sensitivity distribution,SSD)法推导出阿特拉津的短期和长期水质基准分别为6600和1975 ng/L。此外,本研究中还发现莱州湾海域表层海水中阿特拉津的检出率为100%,浓度范围为48.15~118.24 ng/L。风险商法和联合概率曲线法均显示莱州湾海水中阿特拉津的生态风险处于可接受水平。这些结果可为制订阿特拉津的海水水质标准、评估其生态风险提供科学依据。

关键词：莱州湾阿特拉津水质基准生态风险物种敏感度分布毒性数据

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New Methods of Determining the Mixed Mode Stress Intensity Factors for V-Shaped Notch

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上海交通大学学报 2004年第Z2期38卷 188-193页

作者： Lin Zhong-qin yu Haiyan Chen Guanlong Li Shu-hui School of Mechanical Engineering Shanghai Jiaotong University Shanghai200030 P.R.China School of Mechanical Engineering Shanghai Jiaotong University Shanghai200030 P.R.China School of Mechanical Engineering Shanghai Jiaotong University Shanghai200030 P.R.China School of Mechanical Engineering Shanghai Jiaotong University Shanghai200030 P.R.China

In this paper, on the basis of the stress field given by ***, three new photoelastic methods are developed for determining the stress intensity factors K1 and K2 of V-shaped notch. Some photoelastic experiments are performed on a skew -symmetric 45° notch. Measurements of the coordinates components of r,θand fringe order N are made for progressively smaller fringes and used in the proposed methods to solve K1 and *** of apparent K vs. r/l are made and extrapolated to the notch tip to yield the true values of K1 and *** results obtained by the three methods are very close to each other. When the notch problem is simplified as a crack problem, the corresponding equation is identical to the one proposed by D.G. Smith, which shows that the proposed methods are applicable for both notch and crack problems.

关键词： photoelastic stress intensity factors isochromatic fringe V-shaped notch

Radio frequency transistors based on ultra-high purity semiconducting carbon nanotubes with superior extrinsic maximum oscillation frequency

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Nano Research 2016年第2期9卷 363-371页

作者： yu Cao yuchi Che hui Gui Xuao Oao Chongwu Zhou Department of Electrical Engineering University of Southern California Los Angeles CA 90089 USA Department of Chemical Engineering and Materials Science University of Southern California Los Angeles CA 90089 USA

In this paper, we report polyfluorene-separated ultra-high purity semiconducting carbon nanotube radio frequency transistors with a self-aligned T-shape gate structure. Because of the ultra-high semiconducting tube purity and self-aligned T-shape gate structure, these transistors showed an excellent direct current and radio frequency performance. In regard to the direct current characteristics, these transistors showed a transconductance up to 40μS/μm and an excellent current saturation behavior with an output resistance greater than 200 kΩ·μm. In terms of the radio frequency characteristics, an extrinsic maximum oscillation frequency （fmax） of 19 GHz was achieved, which is a record among all kinds of carbon nanotube transistors, and an extrinsic current gain cut-off frequency （fT） of 22 GHz was achieved, which is the highest among transistors based on carbon nanotube networks. Our results take the radio frequency performance of carbon nanotube transistors to a new level and can further accelerate the application of carbon nanotubes for future radio frequency electronics.

关键词： carbon nanotube ultra-high purity radio frequency transistors maximum oscillation frequency T-shape gate

瓜实蝇雄性决定因子基因MoY功能及其上游调控序列活性分析

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昆虫学报 2024年第3期67卷 339-345页

作者：符竣凯温健曹凤勤颜日辉林先武海南大学热带农林学院(农业农村学院、乡村振兴学院) 儋州570228

【目的】本研究旨在鉴定瓜实蝇Zeugodacus cucurbitae雄性决定因子基因MoY上游调控序列,并探索该序列在胚胎早期驱动MoY表达对瓜实蝇性别决定的影响,为后续的瓜实蝇转基因品系的构建提供参考依据以及可用元件。【方法】使用基因组步移... 详细信息

【目的】本研究旨在鉴定瓜实蝇Zeugodacus cucurbitae雄性决定因子基因MoY上游调控序列,并探索该序列在胚胎早期驱动MoY表达对瓜实蝇性别决定的影响,为后续的瓜实蝇转基因品系的构建提供参考依据以及可用元件。【方法】使用基因组步移法扩增瓜实蝇Y染色体连锁的MoY上游序列并测序,将获得的上游序列连接MoY的CDS区构建其驱动MoY表达的质粒;将MoY表达质粒注射进瓜实蝇新鲜的胚胎中,待胚胎孵化后观察成虫的表型以及性比并提取基因组DNA,通过使用基因组DNA扩增MoY以判断获得的MoY上游调控序列是否具有驱动MoY表达的功能,同时分析MoY在胚胎中的表达对性别决定的影响。【结果】克隆并获得瓜实蝇MoY上游1660 bp序列,构建该序列驱动MoY表达的质粒p1660。由注射胚胎发育而来的瓜实蝇雄成虫18头和雌成虫13头及另外发现3头成虫的生殖器发育异常且MoY的扩增结果为阴性,确认为间性个体。【结论】本研究通过对MoY进行基因组步移扩增发现所获得的瓜实蝇MoY上游调控序列具有驱动MoY表达的活性,当MoY于瓜实蝇胚胎早期表达可使原本发育为雌性的个体出现性别逆转的现象。

关键词：瓜实蝇 MoY 上游调控序列性别逆转间性个体

SIRT5缺失对小鼠造血干细胞损伤恢复的影响

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中国实验血液学杂志 2024年第2期32卷 568-576页

作者：邓远遥牟汉川张弦任帆陈陟阳鞠振宇楼慧玲暨南大学衰老与再生医学研究院广东广州510632 广州市第一人民医院老年病科广东广州510180

目的:探讨在5-FU诱导下脱酰基酶Sirtuin 5对小鼠造血干细胞损伤恢复的影响。方法:采用流式细胞术分析SIRT5缺失对小鼠造血干/祖细胞比例,胸腺T细胞的发育情况,外周血和脾脏中T细胞、B细胞和髓系细胞比例的影响。使用5-FU进行化疗损伤诱... 详细信息

目的:探讨在5-FU诱导下脱酰基酶Sirtuin 5对小鼠造血干细胞损伤恢复的影响。方法:采用流式细胞术分析SIRT5缺失对小鼠造血干/祖细胞比例,胸腺T细胞的发育情况,外周血和脾脏中T细胞、B细胞和髓系细胞比例的影响。使用5-FU进行化疗损伤诱导,采用流式细胞术分析SIRT5缺失对骨髓造血干/祖细胞比例的影响,同时检测SIRT5缺失小鼠造血干/祖细胞的细胞周期和凋亡。通过流式分选进行造血干细胞体外培养,分析SIRT5缺失对造血干细胞增殖能力的影响。结果:与野生型相比,SIRT5的缺失不影响小鼠胸腺中T细胞的发育以及外周血和脾脏中T细胞、B细胞和髓系细胞比例。在骨髓中,SIRT5缺失小鼠的造血干/祖细胞比例升高。在5-FU处理的造血损伤情况下,SIRT5缺失会导致小鼠造血干细胞比例下降(P<0.05),并且SIRT5缺失小鼠的造血干/祖细胞由G_(0)期向G_(1)期激活(P<0.05),同时伴随早期凋亡率显著升高(P<0.05)。通过体外单克隆培养,与野生型相比,SIRT5缺失小鼠的造血干细胞克隆形成能力显著下降(P<0.05)。结论:SIRT5缺失导致造血干细胞体外克隆能力下降。在造血应激情况下,SIRT5缺失不利于小鼠造血干/祖细胞损伤后的恢复。

关键词： SIRT5 造血干细胞 5-氟尿嘧啶

Comparison between TVDI and CWSI for drought monitoring in the Guanzhong Plain,China

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Journal of Integrative Agriculture 2017年第2期16卷 389-397页

作者： BAI Jian-jun yu yuan Liping Di College of Tourism and Environment Shaanxi Normal University Center for Spatial Information Science & Systems George Mason University

Temperature vegetation dryness index （TVDI） and crop water stress index （CWSI） are two commonly used remote sens- ing-based agricultural drought indicators. This study explored the applicability of monthly moderate resolution imaging spectroradiometer （MODIS） normalized difference vegetation index （NDVI） and land surface temperature （LST） data for agricultural drought monitoring in the Guanzhong Plain, China in 2003. The data were processed using TVDI, calculated by parameterizing the relationship between the MODIS NDVI and LST data. We compared the effectiveness of TVDI against CWSI, derived from the MOD16 products, for drought monitoring. In addition, the surface soil moisture and monthly pre- cipitation were collected and used for verification of the results. Results from the study showed that：（1） drought conditions measured by TVDI and CWSI had a number of similarities, which indicated that both CWSI and TVDI can be used for drought monitoring, although they had some discrepancies in the spatiotemporal characteristics of drought intensity of this region; and （2） both standardized precipitation index （SPI） and SM contents at the depth of 10 and 20 cm had better correlations to CWSI than to TVDI, indicating that there were more statistically significant relationships between CWSI and SPI/SM, and that CWSI is a more reliable indicator for assessing and monitoring droughts in this region.

关键词： remote sensing agricultural drought TVDI CWSI

低温静止与运动表面结冰特性预测技术研究进展

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哈尔滨工业大学学报 2024年第10期56卷 150-168页

作者：余思锐宋孟杰沈俊孙小琴王海东高润淼北京理工大学机械与车辆学院北京100081 汉阳大学机械工程学院首尔04763 长沙理工大学能源与动力工程学院长沙410004 清华大学航天航空学院北京100084

结冰是一种常见的自然现象,在工业生产流程中也广泛存在,且往往对生活生产造成不利影响。有效运用结冰特性预测技术,可显著降低甚至杜绝各行业因结冰导致的潜在危害。既有研究表明,使用结冰特性预测技术后路面交通事故率可降低65%,若进... 详细信息

结冰是一种常见的自然现象,在工业生产流程中也广泛存在,且往往对生活生产造成不利影响。有效运用结冰特性预测技术,可显著降低甚至杜绝各行业因结冰导致的潜在危害。既有研究表明,使用结冰特性预测技术后路面交通事故率可降低65%,若进一步结合除冰系统,能在80%的结冰场景下实现表面高效防除冰。为有效规避各行业冰灾问题,分别基于道路、输电线两类静止表面与风机叶片、飞机两类运动表面的既有结冰特性预测技术进行了综述与分析,结果表明,对于静止表面,既有技术对结冰厚度等指标的预测精度可达80%以上,运动表面则可达70%以上。既有结冰特性预测技术依原理差异可分为模型驱动法与数据驱动法两种,其中数据驱动法具有很大发展潜力。基于归纳总结的应用于静止与运动两种状态下4种简单冷表面的结冰预测技术,进一步提出该领域的重点研究方向,以期为各类工程场景中低温表面的防除冰技术开发与优化提供参考借鉴。

关键词：结冰特性预测道路表面风机叶片输电线飞机表面模型驱动数据驱动