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Estimation of tree transpiration and response of tree conductance to meteorological variables in desert-oasis system of Northwest China

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Science China Earth Sciences 2004年第Z1期47卷 9-20页

作者： CHEN Rensheng kang ersi zhang Zhihui ZHAO Wenzhi SONG Kechao zhang jishi lan yongchao Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China

Transpirations of three dominated tree species, namely Mongol Scotch Pine (Pinus sylvestris var. mongolica Litvin), White elm (Ulmus pumila) and Gansu Poplar (Populus gansuensis Wang et Yang) in oasis shelter forest (Linze site) and of two dominated tree species,namely Euphrates Poplar (Populus euphratica Oliv.) and Russia olive (Elaeagnus angustifolia Linn.) in lowland desert (Erjinaqi site) have been estimated using measured sapflow in summer,autumn and winter, 2002 and in spring, 2003. An ENVIS System was used for each site to measure microclimate variables, soil moisture and sapflow every half an hour, and the study time scale is one day. In the 104 days of observation during the growing season at the Linze site, the average daily sapflow of Gansu Poplar is 9.93L·d-1,and the average transpiration per unit leaf area is 1.99mm·*** White elm tree,the daily average sapflow is 4.08L·d-1,while the daily average transpiration per unit leaf area is 0.49mm·*** values for Mongol Scotch Pine are 3.91L·d-1 and 0.25mm·d-1,*** the total 73 days of observation during the growing season at the Erjinaqi site, the daily average sapflows of Russia olive and Euphrates Poplar are 12.1 and 20.97L·d-1,respectively,and the average transpirations per unit leaf area are 0.22 amd 0.31mm·d-1,*** the observation period of the growing season,tree conductances of Mongol Scotch Pine, White elm, Gansu Poplar or Russia olive show an exponential relationship with the daily average air temperature or vapour pressure deficit, but the relationship is not so obvious between tree conductance and global radiation. The transpiration process of each tree species is affected by all the observed four environmental variables. The response of tree conductance to different climatic factors changes with tree species. The effect of the same factor to the same tree species is also variable in different growing stages. The sapflow of every tree species is relatively large in later

关键词： sapflow tree conductance leaf area transpiration soil water content climatic variable.

Causes and statistical characteristics of bridge failures:A review

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Journal of Traffic and Transportation Engineering(English Edition) 2022年第3期9卷 388-406页

作者： Guojing zhang yongjian Liu Jiang Liu Shiyong lan Jian Yang School of Highway Chang'an UniversityXian 710064China Research Center of Highway Large Structure Engineering on Safety of Ministry of Education Chang'an UniversityXi'an 710064China AECOM New YorkNY 10158USA

Bridge failure, which is generally associated with serious economic and life losses, is defined as the incapacity of a constructed bridge or its components to perform as specified in the design and construction requirements. This paper presents an overview of current researches on the typical characteristics and causes of bridge failures based on 10 former investigations. Principal causes can be divided into internal causes and external causes or natural factors and human factors. Design error, construction mistakes, hydraulic, collision, and overload are the top 5 leading causes of bridge failures, resulting in more than70% of the bridge failures. Causes of bridge failures are closely related to regional economy,structural type, type of use, material type, and service age. The failure rate is very high for steel bridges, which is inseparable from excessive emphasis on structure strength but lack of consideration on structure stability and fatigue in early years. Researchers need to strengthen their research on the stability and fatigue of steel bridges, as well as inspection and maintenance. Extreme loads such as flood, collision, and overload contribute to a large number of bridge failures because of the lack of extreme loads data and design theory defects. It is critical for such bridges to have sufficient redundancy and capacity protection measures to reduce the probability of bridge failure due to extreme loads. Previous statistical methods and classification methods for the characteristics and causes of bridge failures lack unified standards, and a more scientific method needs to be established. A comprehensive electronic database on bridge damage and failures needs to be developed to establish damage models and conduct forensic studies to improve the design theory and specifications.

关键词： Bridge engineering Bridge failure Statistical characteristic Failure cause Case study

The relationship between ENSO cycle and high and low-flow in the upper Yellow River

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Journal of Geographical Sciences 2003年第1期13卷 105-111页

作者： lanyongchao dingyongjiang kangersi MAQuanjie zhangjishi ColdandAridRegionsEnvironmentalandEngineeringResearchInstitute CASLanzhou730000China lanzhouadministrativeOfficofHydrologyandWaterResourcesoftheUpperReachesoftheYellowRier Lanzhou730030China

Firstly, the hydrological and meteorological features of the upper reaches of the Yellow River above Tangnag are analyzed based on observation data, and effects of EI Nino and La Ni na events on the high and low flow in the upper Yellow River are discussed. The results show El Nino and La Nina events possess consanguineous relationship wi th runoff in the upper Yellow River. As a whole, the probability of low fl ow occurrence in the upper Yellow River is relatively great along wit h the occurrence of El Nino event. Moreover, the flood in the upper Yellow River occurs frequently with the occurrence of La Nina event. Besides, the results also show dissimilarity of El Nino event occurri ng time exerts greater impact on high flow and low flow in the uppe r Yellow River, that is, the probability of drought will be greater in the sam e year if El Nino event occurs in spring, the high-flow may happen in this y ear if El Nino occurs in summer or autumn; the longer the continuous period of El Nino is, the lower the runoff in the upper Yellow River is.

关键词： El Nino event La Nina event the upper Yellow River high-flow and low-flow

Impact of climate change and variability on water resources in Heihe River Basin

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Journal of Geographical Sciences 2003年第3期13卷 286-292页

作者： NHANGjishi kangersi lanyongchao CHENRensheng lanzouUniversity Lanzhou730000China ColdandAridRegionEnvironmentalandEngineeringResearchInstitute CAS.Lanzhou730000China

Studies indicate that the climate has experienced a dramatic change in the Heihe River Basin with scope of temperature rise reaching 0.5-1.1 o C in the 1990s compared to the mean value of the period 1960-1990, precipitation increased 18.5 mm in the 1990s compared to the 1950s, and 6.5 mm in the 1990s compared to the mean value of the period 1960-1990, water resources decreased 2.6×10 8 m 3 in the 1990s compared to the 1950s, and 0.4×10 8 m 3 in the 1990s compared to the mean value of the period 1960-1990. These changes have exerted a greater effect on the local environment and socio-economy, and also made the condition worsening in water resources utilizations in the Heihe Rver Basin.

关键词： climate change water resources variability Heihe River Basin of Northwest China

植物精油微胶囊制备及其在果蔬保鲜包装中的应用

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食品与发酵工业 2021年第3期47卷 274-280页

作者：张兰徐永建陕西科技大学轻工科学与工程学院陕西西安710021 陕西省造纸技术及特种纸品开发重点实验室陕西西安710021

植物精油作为天然抗菌剂和抗氧化剂,在果蔬保鲜方面的研究与应用非常广泛,而微胶囊技术可有效控制植物精油有效成分的缓慢释放,从而达到长效保鲜效果。该文介绍了近年来国内外植物精油微胶囊的结构、制备、壁材以及在果蔬保鲜活性包装... 详细信息

植物精油作为天然抗菌剂和抗氧化剂,在果蔬保鲜方面的研究与应用非常广泛,而微胶囊技术可有效控制植物精油有效成分的缓慢释放,从而达到长效保鲜效果。该文介绍了近年来国内外植物精油微胶囊的结构、制备、壁材以及在果蔬保鲜活性包装中的应用,为植物精油微胶囊的研究提供方向,对于拓展植物精油应用领域具有重要的意义。

关键词：植物精油微胶囊果蔬保鲜活性包装抗菌

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电化学在ICF靶制备中的新应用

强激光与粒子束 2010年第1期22卷 58-62页

作者：杜凯张素银周兰方瑜张林唐永建中国工程物理研究院激光聚变研究中心四川绵阳621900

报道了近年来在电解加工技术制备理论密度金属薄膜和电沉积技术制备金属纳米丝阵列材料等领域取得的进展。采用硫酸+甲醇电解液体系获得了表面粗糙度小于30nm的钛膜。采用阳极氧化铝模板电沉积技术制备出长度约10μm、直径约300nm的金... 详细信息

报道了近年来在电解加工技术制备理论密度金属薄膜和电沉积技术制备金属纳米丝阵列材料等领域取得的进展。采用硫酸+甲醇电解液体系获得了表面粗糙度小于30nm的钛膜。采用阳极氧化铝模板电沉积技术制备出长度约10μm、直径约300nm的金纳米丝阵列。主要讨论了电解液配方及电解加工参数的选择,金属纳米丝直径与长度的控制等问题。

关键词：电化学惯性约束聚变电解阳极化氧化铝纳米丝

一种改进点线特征融合的双目视觉惯性定位算法

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航空制造技术 2023年第10期66卷 85-92页

作者：丁晓晏玉祥张永建兰卫旗白晓亮航空工业成都飞机工业(集团)有限责任公司成都610092 西北工业大学西安710072

在复杂产品装配过程中,对增强现实设备定位是实现虚拟引导信息与装配现场实时融合的核心。传统基于标签或预先构建离线装配基体模型的定位方式,存在装配任务与视觉定位兼容性低,单一视觉定位鲁棒性和稳定性差的问题。利用多传感器融合... 详细信息

在复杂产品装配过程中,对增强现实设备定位是实现虚拟引导信息与装配现场实时融合的核心。传统基于标签或预先构建离线装配基体模型的定位方式,存在装配任务与视觉定位兼容性低,单一视觉定位鲁棒性和稳定性差的问题。利用多传感器融合的视觉惯性导航方式进行定位,可提高定位的精度和鲁棒性,有效提高复杂产品装配质量和效率。本文提出了一种基于点线特征融合的双目视觉惯性定位算法,对双目相机和惯性测量单元(Inertial measurement unit,IMU)进行联合标定,并通过ORB和LSD线端融合的点线特征提取匹配,采取视觉和IMU紧耦合的方式,建立基于点线特征的视觉惯性融合的位姿误差融合模型。对比VINS-Fusion、PL-VIO和本文改进IPLVIO算法,结果表明IPL-VIO算法在结构化场景下的绝对位移和旋转误差比原算法误差更小,同时结构化场景信息更加丰富,能够应用在弱纹理的AR装配现场中,为增强现实辅助装配平台提供稳定可靠的位姿数据。

关键词：增强现实(AR) 双目视觉惯性测量单元(IMU) 点线特征定位

益气温阳利水方辅助治疗对经导管主动脉瓣置换术后患者生活质量及预后的影响

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中医杂志 2018年第14期59卷 1210-1213页

作者：兰玥张文佳殷仕洁吴永健于欣马丽红中国医学科学院阜外医院

目的探讨益气温阳利水方辅助治疗对经导管主动脉瓣置换术(TAVR)术后患者心功能、症状及生活质量的影响。方法选取接受TAVR治疗的主动脉瓣重度狭窄患者100例,将其随机分为治疗组和对照组各50例。对照组进行常规西药治疗,治疗组在对照组... 详细信息

目的探讨益气温阳利水方辅助治疗对经导管主动脉瓣置换术(TAVR)术后患者心功能、症状及生活质量的影响。方法选取接受TAVR治疗的主动脉瓣重度狭窄患者100例,将其随机分为治疗组和对照组各50例。对照组进行常规西药治疗,治疗组在对照组基础上联合中药益气温阳利水方治疗,两组疗程均为8周。治疗后观察临床疗效、中医证候疗效,治疗前后比较两组中医症状积分、氨基末端B型钠尿肽原(NT-pro BNP)、6分钟步行距离、左室射血分数(LVEF)、生活质量评分,统计平均住院日和再住院率。结果治疗组临床疗效总有效率(90%)高于对照组(82%),治疗组中医证候疗效总有效率(86%)高于对照组(68%)(P<0.05)。治疗组治疗后心悸、气短、乏力及中医症状总积分均较治疗前明显降低,而对照组仅气短较治疗前降低(P<0.05或P<0.01)。与对照组治疗后比较,治疗组心悸、气短、乏力、浮肿、中医症状总积分、生活质量评分及NT-pro BNP均明显降低,6分钟步行距离及LVEF值均明显升高(P<0.05或P<0.01)。治疗组平均住院日及再住院率明显低于对照组(P<0.05或P<0.01)。结论益气温阳利水方辅助治疗在TAVR术后稳定病情、提高心功能、改善症状及生活质量方面具有明显优势。

关键词：主动脉瓣狭窄经导管主动脉瓣置换术生活质量益气温阳利水方

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纳米药物的监督管理

中国药事 2012年第9期26卷 923-928页

作者：耿志旺何兰张启明杨永健上海市食品药品检验所上海201203 中国食品药品检定研究院

目的为加强我国纳米药物监管,促进纳米药物的健康发展提供借鉴。方法综述了欧洲、美国、加拿大以及日本药监部门对纳米药物发展的应对策略以及采取的具体措施。结果与结论纳米药物的发展给现有的药品监督管理带来挑战,发达国家的药监部... 详细信息

目的为加强我国纳米药物监管,促进纳米药物的健康发展提供借鉴。方法综述了欧洲、美国、加拿大以及日本药监部门对纳米药物发展的应对策略以及采取的具体措施。结果与结论纳米药物的发展给现有的药品监督管理带来挑战,发达国家的药监部门正在积极了解纳米药物的性质,研究纳米药物质量控制方法和监督管理策略。

关键词：纳米药物监督管理