检索结果-南通市图书馆

财务与会计（理财版） 2012年第7期 58-58页

var（Value at Risk）即“在险价值”，是指在一定概率水平（置信度）下，某一金属资产或证券组合价值在未来特定时期内的最大可能损失。

关键词： var "在险价值" 概率水平置信度证券组合市场

Dynamic var planning methodology to enhance transient voltage stability for failure recovery

在线全文

学校读者我要写书评

暂无评论

Journal of Modern Power Systems and Clean Energy 2018年第4期6卷 712-721页

作者： Di YANG Haozhong CHENG Zeliang MA Liangzhong YAO Zhonglie ZHU State Grid Pudong Power Supply Company SMEPC Department of Electronic Information and Electrical Engineering Shanghai Jiao Tong University East China Grid Company Limited China Electric Power Research Institute

In recent years, failure recovery after faults is concerned and discussed worldwide as an important and hot topic. Facing the challenge of heavy loads and ultrahigh voltage transmission, it's urgent to propose some solutions to enhance transient voltage stability for failure recovery. Therefore, a novel dynamic volt ampere reactive(var) planning methodology is proposed in this paper to help failure recovery and improve transient voltage stability after contingencies. First, a transient voltage fluctuation(TVF) index is proposed to evaluate transient voltage condition after faults. Then dynamic compensationsensitivity is presented for searching the best candidate locations. Following that, the dynamic var planning methodology based on an improved Tent chaos multi-objective algorithm is discussed in detail. There are two optimization objects in the optimization. One is to minimize TVF to enhance transient voltage stability for failure recovery. And the other optimization is to minimize dynamic var investment cost and operation cost. Finally,IEEE 39 power system and a practical power system are analyzed and discussed. The proposed dynamic var planning methodology can support enough reactive power for failure recovery. With the least SVC planning amount and the power loss cost, it can greatly decrease the system TVF index and enhance the transient voltage stability. It's proved that the proposed dynamic var planning optimization is effective and helpful for safety operation of power system.

关键词： Dynamic var planning Failure recovery Improved Tent mapping chaos optimization Transient stability

Morphological characteristics of tree crowns of Cunninghamia lanceolata var. Luotian

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2020年第3期31卷 837-856页

作者： Yezhou Xu Chaoqun Du Guowei Huang Zhenfang Li Xiangyang Xu Jingjin Zheng Chu Wu Hubei Academy of Forestry Wuhan 430075People’s Republic of China Forestry Bureau of Luotian County Huanggang 438000People’s Republic of China College of Horticulture and Gardening Yangtze UniversityJingzhou 434025HubeiPeople’s Republic of China

The structural characteristics of the tree crowns of Cunninghamia lanceolata var. Luotian(herein, Luotian), a natural variety of C. lanceolata(Chinese-fir, herein Lanceolata) in China, were analyzed using trunk and branch measurements and biomass determinations. Samples from two typical cultivated varietal populations were collected, including twenty-six 15–23-year-old trees of Luotian from a plantation, and nine 16–23-year-old trees of Lanceolata. Our results show that Luotian and Lanceolata samples differed significantly in crown structure, morphological indices, and biomass:(1) the oldest live branches on Luotian trees were 5–6 years old and 8–11 years old on Lanceolata. The ages of the live branches were not affected by the ages of the Luotian trees, while live branch ages increased with ages of Lanceolata trees;(2) the maximumbranching order of Luotian was level two. Compared to Lanceolata, the average number of first-order lateral branches(i.e., branches emerging from the trunk) and the number of first-order lateral branch whorls per sample tree were 12.9% and 32.2% lower, respectively, in ***, the average number of branches within a single whorl was 21.8% greater in Luotian;the average number of branch whorls at crown height was 51.1% greater. Thus,the Luotian variety has thicker branches;(3) the average lateral branch angles in Luotian and Lanceolata sample trees were 105.2° and 61.4°, respectively. The branch angles in 53.0% of lateral branches on Luotian ranged from105° to 135°, but 30° to 90° in 96% of the lateral branches on Lanceolata. Within the same crown layer, the average branch angle was 1.6–2.2 times greater in Luotian, and the angle was directly proportional to crown thickness;(4) the average base diameter and branch length on Luotian were1.3 cm and 75.8 cm, respectively, and 1.6 cm and112.2 cm for Lanceolata. For individual trees, branch growth differed significantly(p < 0.01) between Luotian and Lanceolata. However, the lateral bran

关键词： Cunninghamia lanceolata var Luotian Cunninghamia lanceolata Tree crown Morphological characteristics variation

Effects of an ectomycorrhizal fungus on the growth and physiology of Pinus sylvestris var. mongolica seedlings subjected to saline-alkali stress

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2020年第3期31卷 781-788页

作者： Dachuan Yin Saiyaremu Halifu Ruiqing Song Jinyu Qi Xun Deng Jifeng Deng College of Forestry Shenyang Agricultural UniversityShenyang 110866People’s Republic of China College of Forestry Northeast Forestry UniversityHarbin 150040People’s Republic of China Forestry Protection Institute of Heilongjiang Forestry Academy Harbin 150040People’s Republic of China

This research investigates the mechanism of increased salinity tolerance of ectomycorrhizal fungiinoculated P. sylvestris var. mongolica to provide a theoretical basis for the application of the fungus in saline *** effects due to inoculation of seedlings with Suillus luteus(a symbiotic ectomycorrhizal fungus), were determined in four kinds of saline–alkali soils. Growth and physiological indicators, including photosynthetic characteristics, plant height, biomass, photosynthetic pigments,catalase(CAT) and superoxide dismutase(SOD) enzyme levels, and malondialdehyde(MDA), an organic marker for oxidative stress, and soluble protein levels were determined. Mycorrhizal colonization rate decreased with increasing saline–alkalinity and growth of inoculated seedlings was significantly enhanced. Biomass and chlorophyll contents also increased significantly. SOD and CAT activities were higher than in non-inoculated seedlings. However, MDA content decreased in inoculatedseedlings. Soluble protein content did not increase significantly. Inoculation with a symbiotic ectomycorrhizal fungus could enhance the saline–alkali tolerance of P. sylvestris var. mongolica. Growth and physiological performance of inoculated seedlings were significantly better than that of uninoculated seedlings. The results indicate that inoculated P. sylvestris var. mongolica seedlings may be useful in the improvement of saline–alkali lands.

关键词： Ectomycorrhizal fungi Saline–alkali stress Pinus sylvestris var mongolica Physiological and biochemical mechanisms

Proximate and mineral components of Viscum album var. coloratum grown on eight different host tree species

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2019年第4期30卷 1245-1253页

作者： Chul-Woo Kim Chan-Hoon An Hyun-Seok Lee Jae-Seon Yi Eun Ju Cheong Sang-Hyun Lim Hee-Yeon Kim Forest Bioresources Department National Institute of Forest Science39 OnjeongroGwonseon-guSuwon 16631Republic of Korea Forest Medicinal Resources Research Center National Institute of Forest ScienceSobaek-ro 2009PunggiYoungjuGyungsangbuk-do 36040Republic of Korea Program of Forest Resources Division of Forest ScienceCollege of Forest and Environmental SciencesKangwon National UniversityChuncheon 24341Republic of Korea Agriproduct Processing Experiment Station Gangwon-do Agicultural Research and Experiment ServicesChuncheon 24203Republic of Korea

Mistletoes are parasite plants growing on various tree species,taking nutrients from the *** compounds of mistletoe were used in medicine and these mistletoes were commonly collected from oak species that were not well *** analyzed the nutritional value by measuring proximate and mineral components of Korean mistletoe(Viscum album ***)from various host *** was the most proximate component in both leaves and twigs followed crude protein,crude fiber,crude ash and crude *** the contents of the proximate components and minerals varied among hosts and between plant parts,leaves contained higher crude protein and ash,and more minerals except for magnesium than twigs,although no significant difference was found inmistletoe grown on Prunus *** were significant differences of proximate and mineral contents depending on the host *** grown on Chaenomeles sinensis contained higher levels of carbohydrates,crude fat,crude ash,magnesium,calcium,sodium,iron,and zinc than mistletoe grown on other *** grown on *** contained high mineral levels of potassium,copper and *** nutritional value of mistletoes were greatly influenced by the host species but among the hosts,specific nutrients accumulated in leaves more than in twigs,and vice *** on the analysis,Korean mistletoe contains relatively good quality of nutrients and has high potential for dietary supplements as well as for medicinal compounds.

关键词： Mistletoe Viscum album var coloratum Proximate compositions Mineral contents Nutritional value Host species

Five New Flavonoids from Bidens Pilosa L. var. Vadiata SCH.-BIP

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1997年第7期8卷 599-602页

作者： Wang, J Yang, H Lin, ZW Sun, HD ACAD SINICA KUNMING INST BOTLAB PHYTOCHEMKUNMING 650204PEOPLES R CHINA YUNNAN UNIV DEPT CHEMKUNMING 650091PEOPLES R CHINA

Five new flavonoids were isolated from the aerial parts of Bidens pilosa L. var. vadiata Sch.-Bip.. Their structures were established on the basis of spectroscopic methods.

关键词： Vadiata SCH OAC BIP Five New Flavonoids from Bidens Pilosa L var

Analysis of var genes cloned from a Plasmodium falcivarum isolate in China

在线全文

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Medicine 2012年第2期5卷 85-90页

作者： Ning Jiang Li Meng Hui-Jun Lu Wei Kang Shuai Peng Wei-Qing Pan Ji-Gang Yin Qi-Jun Chen Key Laboratory of Zoonosis Ministry of EducationInstitute of ZoonosisJilin University Department of Pathogen Biology Laboratory of Parasitology Institute of Pathogen BiologyChinese Academy of Medical Sciences

Objective:To analyse the rar gene repertoire and characterise the rhondroitin sulphate A (CSA)-binding activity of the Duffy-binding like(I)BI.) domains encoded by the var2csa gene of a Plasmodium falciparum(***) isolate in Hainan Province,***:The sequences of var DBL1 regions were PCR-amplified,sequenced and the sequence characteristics was bioinformalically *** proteins encoded by the var2csa genes were expressed and *** binding activities of the recombinant proteins to CSA receptor was detected by ELISA ***:Fifty six unique DBI.a sequences were obtained,and the sequences represented similar diversity to the var genes of the genome parasite *** are two var2csa genes in the *** isolated from Hainan *** in other falciparum parasites such as HB3,the two var2csa genes are more *** receptor-binding capacity of DBL-5εand DBI.-6 e domains of HN var2CSA was ***:This work represented the diversity of rar genes of a *** isolate in China.

关键词： Malaria Plasmodium falciparum Antigenic variation var gene

Proteomic analysis of blast-resistant near-isogenic lines derived from japonica rice, var. Yunyin, infected with Magnaporthe oryzae

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2014年第32期59卷 4312-4322页

作者： Weimin Xue Xiaohui Mao Yidong Wei Lian Ling Yongsheng Zhu Shuilin He Jianfu Zhang Huaan Xie Rice Research Institute Fujian Academy of Agricultural Sciences National Engineering Laboratory of Rice South Base of National Key Laboratory of Hybrid Rice of China College of Crop Science Fujian Agriculture and Forestry

Rice blast is one of the most devastating diseases in the world and outbreaks occur *** differences in protein expression between blast resistant and susceptible near-isogenic lines(NILs)of japonica rice *** infected with Magnaporthe oryzae were analyzed using proteomics,indicated that 67 different proteins were identified from 75 obtained proteins using the matrixassisted laser desorption/ionization time-of-flight mass spectrometry *** specific expression proteins,43 up-regulated proteins and 17 down-regulated proteins were identified among the 67 *** bioinformatical analysis demonstrated that these 67 different proteins were involved in many biological physiological processes including five proteins related to photosynthesis,25 proteins related to metabolism,six proteins related to antioxidants,10 proteins related to protein synthesis and modification,five proteins related to signal transduction,four proteins related to adversity stress and 12 non-functional *** identified proteins were directly or indirectly related to *** proteins related to different physiological processes were *** cDNA sequences were predicted and their expression patterns were analyzed using real-time PCR,demonstrated that the genes would response to *** and the response blindingly different between blast resistant and blast susceptible NILs.

关键词：蛋白质组学近等基因系稻瘟病菌 var 粳稻学分感染基质辅助激光解吸

SWINANINE　C＆D，TWO　NEW　DITERPENE　ALKALOIDS　FROM　DELPHINIUM　SWINANENSE　var　LEPTOPOGON

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1995年第4期6卷 309-310页

作者： Suo Hing ZHANG Ji HA Qing Yu OU (Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou730000)a: (Department of Biology, Lanzhou University, Lanzhou 730000) Chinese Acad Sci Lanzhou Inst Chem Phys Lanzhou 730000 Peoples R China Lanzhou Univ Dept Biol Lanzhou 730000 Peoples R China

s: Two new diterpene alkaloids named swinanine C and D were isolated from Delphinium swinanense var leptopogon (H. -M. ) W. T. Wang. Their structures were elucidated by means of spectral methods , principally 1H-NHR, ... 详细信息

关键词： var LEPTOPOGON SWINANENSE FROM DITERPENE ALKALOIDS DELPHINIUM

An Application of var System for Investment Model

在线全文

学校读者我要写书评

暂无评论

厦门大学学报（自然科学版） 2002年第S1期41卷 241-242页

作者： ZHONG Song-ting, HUANG Guo-shi (Department of Automation, Xiamen University, Xiamen 361005, China)

By the reality of investment in China, a fished inv es tment model is obtained and modified by Hicks multiplicator-accelerator model. It preferable explains the status quo of investment in China. In China, The valu e of investment in period t is not only having relation to the investment of per iod t-1 and Gross Domestic Products of period t-1 (as the model of Hicks and S amuelson described) but also having some relation to the investment of period t -*** is the reason that the model of Hicks or Samuelson can’t use in China d irectly. Then the model is analyzed by var(Vector Autoregressive) system. The VA R is a new model of macro-economics measurement. The advantage of var is that i t is avoid some complex problems as measuring off the endogenous variable and ex ogenous variable and the identifiability of model. It is composed of some dynami c equations. And it regards all the variables in equations as endogenous variabl es. By using statistical data in China a model about Gross Domestic Product and Investment is obtained and a forecasting is designed. The correlation is cal culated using Matlab. The results of the correlation of Gross Domestic Products, Investment and Consumption can analyze the rationality of policy of country and forecast the trend of economics. And it is profitable for exactly understand th e circumstance of investment. The shortage of this paper is that the gross of st atistical data is too small, only the data after the year of 1978 is available.

关键词： var fished project investment forecast