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Conserving plants within and beyond protected areas-still problematic and future uncertain 被引量:2
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作者 Vernon H.Heywood 《Plant Diversity》 SCIE CAS CSCD 2019年第2期36-49,共14页
Against a background of continuing loss of biodiversity, it is argued that for the successful conservation of threatened plant species we need to ensure the more effective integration of the various conservation actio... Against a background of continuing loss of biodiversity, it is argued that for the successful conservation of threatened plant species we need to ensure the more effective integration of the various conservation actions employed, clarify the wording of the CBD targets and provide clearer operational guidance as to how they are to be implemented and their implementation monitored. The role and effectiveness of protected areas in conserving biodiversity and in particular plant species in situ are discussed as are recent proposals for a massive increase of their extent. The need for much greater effort and investment in the conservation or protection of threatened species outside protected areas where most plant diversity occurs is highlighted. The difficulties involved in implementing effective in situ conservation of plant diversity both at an area-and species/population-based level are discussed. The widespread neglect of species recovery for plants is noted and the desirability of making a clearer distinction between species recovery and reintroduction is emphasized. Key messages from a global overview of species recovery are outlined and recommendations made, including the desirability of each country preparing a national species recovery strategy. The projected impacts of global change on protected areas and on species conservation and recovery, and ways of addressing them are discussed. 展开更多
关键词 plant CONSERVATION CBD TARGETS protected areas Species recovery CONSERVATION approaches
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Fractional Gradient Descent RBFNN for Active Fault-Tolerant Control of Plant Protection UAVs
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作者 Lianghao Hua Jianfeng Zhang +1 位作者 Dejie Li Xiaobo Xi 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第3期2129-2157,共29页
With the increasing prevalence of high-order systems in engineering applications, these systems often exhibitsignificant disturbances and can be challenging to model accurately. As a result, the active disturbance rej... With the increasing prevalence of high-order systems in engineering applications, these systems often exhibitsignificant disturbances and can be challenging to model accurately. As a result, the active disturbance rejectioncontroller (ADRC) has been widely applied in various fields. However, in controlling plant protection unmannedaerial vehicles (UAVs), which are typically large and subject to significant disturbances, load disturbances andthe possibility of multiple actuator faults during pesticide spraying pose significant challenges. To address theseissues, this paper proposes a novel fault-tolerant control method that combines a radial basis function neuralnetwork (RBFNN) with a second-order ADRC and leverages a fractional gradient descent (FGD) algorithm.We integrate the plant protection UAV model’s uncertain parameters, load disturbance parameters, and actuatorfault parameters and utilize the RBFNN for system parameter identification. The resulting ADRC exhibits loaddisturbance suppression and fault tolerance capabilities, and our proposed active fault-tolerant control law hasLyapunov stability implications. Experimental results obtained using a multi-rotor fault-tolerant test platformdemonstrate that the proposed method outperforms other control strategies regarding load disturbance suppressionand fault-tolerant performance. 展开更多
关键词 Radial basis function neural network plant protection unmanned aerial vehicle active disturbance rejection controller fractional gradient descent algorithm
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The Register and Characteristics of Chinese Key Protected Wild Plants in Dabie Mountains National Nature Preserve, Hubei Province 被引量:1
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作者 Jun QI Peng FU +3 位作者 Jian FU Aiguo ZHEN Li JIANG Yuanping FANG 《Agricultural Biotechnology》 CAS 2022年第2期21-22,26,共3页
A study was conducted on the newly promulgated key protected wild plants distributed in the Dabie Mountains National Nature Reserve in Hubei in 2021.According to statistics,Dabie Mountains National Nature Reserve of H... A study was conducted on the newly promulgated key protected wild plants distributed in the Dabie Mountains National Nature Reserve in Hubei in 2021.According to statistics,Dabie Mountains National Nature Reserve of Hubei Province has a total of 41 species of wild plants under national key protection,including 7 species in the first class and 34 species in the second class.Among them,6 are cultivated species,4 in the first class,and 2 species in the second class.The characteristics of Chinese key protected wild plants in the Dabie Mountains National Nature Reserve in Hubei Province were analyzed. 展开更多
关键词 Dabie Mountains National Nature Preserve Chinese protected plant Wild plants
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Analysis of Textbook "Garden Plant Protection" Construction in Agricultural and Forestry Universities or Higher Vocational Colleges
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作者 马国胜 陈娟 《Journal of Landscape Research》 2009年第2期74-78,共5页
The survey of textbook 'Garden Plant Protection' was introduced in this study,and the necessity of textbook 'Garden Plant Protection' construction in agricultural and forestry universities or higher vo... The survey of textbook 'Garden Plant Protection' was introduced in this study,and the necessity of textbook 'Garden Plant Protection' construction in agricultural and forestry universities or higher vocational colleges was also analyzed.Aimed at the status of textbook 'Garden Plant Protection' construction in agricultural and forestry universities or higher vocational colleges,the corresponding ideas for its construction were put forward. 展开更多
关键词 Agricultural and FORESTRY or HIGHER VOCATIONAL education GARDEN plant protection TEXTBOOK CONSTRUCTION
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Plant Variety Protection and DUS Testing Technique 被引量:6
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作者 LI Xiao-hui, LI Xin-hai, ZHANG Shi-huang, LI Ming-shun and LI Wen-hua(Institute of Crop Breeding and Cultivation, Chinese Academy of Agricultural Sciences /Key Laboratory of CropGenetics and Breeding , Ministry of Agriculture/AMBIONET-China Laboratory , Beijing 100081 , P. R. China College of Agronomy , Northeast Agricultural University, Harbin 150030, P.R.China) 《Agricultural Sciences in China》 CAS CSCD 2002年第12期1400-1403,共4页
DUS testing technique used for plant variety protection was reviewed in the paper, and some suggestions were made on how to establish the appropriate technology system in China. Meanwhile, the potential exploitation o... DUS testing technique used for plant variety protection was reviewed in the paper, and some suggestions were made on how to establish the appropriate technology system in China. Meanwhile, the potential exploitation of the technique was discussed. 展开更多
关键词 plant variety protection DUS testing DNA fingerprinting
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Root structure of slope protection plants in a high-grade highway 被引量:3
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作者 WANG Jing-hong LI Xing-tao LIU Xiao-dong Wang Fei LIU Yu 《Journal of Forestry Research》 SCIE CAS CSCD 2011年第2期311-313,共3页
Root length and root length density of Lespedeza bicolor,Amorpha fruticosa,and Sea buckthorn were investigated in a country highway-TongSan highway(Tongjiang to Sanya) in Heilongjiang Province,China.The root lengths... Root length and root length density of Lespedeza bicolor,Amorpha fruticosa,and Sea buckthorn were investigated in a country highway-TongSan highway(Tongjiang to Sanya) in Heilongjiang Province,China.The root lengths were divided into five root orders according to Pregizter sequence classification method.Results show that sea buckthorn roots are dominated by coarse roots in the horizontal growth,while L.bicolor has a large proportion of fine roots in vertical conical growth and A.fruticosa is in depth growth.Root length density of L.bicolor in all the root sequences is higher than that of sea buckthorn and A.fruticosa.On the basis of the root structure,it is inferred that L.bicolor roots mainly absorb the surface soil moisture for its normal growth;in contrast,A.fruticosa has good uptake ability to deep soil water.The root structure of sea buckthorn implies that it has a strong drought resistance. 展开更多
关键词 seasonal frost area slope protection plant root structure
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Study on Lightning Protection Design of DCS in a Nuclear Power Plant 被引量:3
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作者 Jie Liu Yunfeng Zhu +1 位作者 Fang Tian Jin Wang 《Meteorological and Environmental Research》 CAS 2013年第10期14-18,共5页
DCS (distributed control system) plays a decisive role in the overall operation of a nuclear power plant. If DCS fails, it will seriously affect the normal production of nuclear power plant, causing great losses. So... DCS (distributed control system) plays a decisive role in the overall operation of a nuclear power plant. If DCS fails, it will seriously affect the normal production of nuclear power plant, causing great losses. So it is very important to take perfect lightning protection measures on DCS of the nuclear power plant. In this paper, according to the actual situation of DCS in a nuclear power plant, by controlling lightning point, securely booting lightning into the ground network, improving low-resistance ground network, eliminating ground loops, determining the safety space, surge protection of power and signal, a set of complete lightning protection design scheme was systematically put forward. Some specific lightning protection measures were highlighted, such as the DCS grounding, equipotential bonds and shields, and some specific considerations were put forward. All of these could offer reference in the practical application. 展开更多
关键词 DCS Lightning protection Nuclear power plant GROUNDING China
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In-situ Protection Management and Conservation Study of Some Medicinal Plants 被引量:2
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作者 Hassan SHER Z.D.KHAN +1 位作者 A.U.KHAN Farrukh HUSSAIN 《云南植物研究》 CSCD 北大核心 2005年第1期27-36,共10页
In-situ study on eleven commercially important species viz; Adiantum capillus-veneris L, Bergenia ciliata (Haw) Sternb, Colchicum luteum Baker, Polygonum amplexicaule D.Den, Cuminum cyminum L, Dioscorea deltoidea Wall... In-situ study on eleven commercially important species viz; Adiantum capillus-veneris L, Bergenia ciliata (Haw) Sternb, Colchicum luteum Baker, Polygonum amplexicaule D.Den, Cuminum cyminum L, Dioscorea deltoidea Wall Kunth,L Morchella esculenta L, Paeonia emodi Wall ex H Kf, Podophyllum hexandrum (Royle) Chatt & Mukh, Valeriana wallichii DC and Viola serpens Wall ex Roxb was conducted in four locations viz; Malam (1 400 to 2 000?m),Bargin (1 700 to 2 300?m),Biakand (1 500 to 2 100?m) and Shinko (2 100 to 2 700?m).The data was recorded from both protected and unprotected sites of each site.Each site had 3 altitudinal sampling point.The density, herbage coverage and fresh biomass were determined in each locations for every species.All the investigated parameters generally showed an increase of 3 to 6 times over unprotected sites in each locations. Morchella esculenta,Dioscorea deltoidea,Colchicum luteum and Podophyllum hexandrum were absent in all unprotected sites while other species had low values in these sites.The investigated parameters of Colchicum luteum,Bergenia ciliata,Paeonioa emodi,Dioscorea deltoidea and Podophyllum hexandrum generally increased with the increasing elevation.Soil analysis,soil and air temperatures were recorded for each site.The air and soil temperature were slightly higher in open areas than in the protected site and showed decrease with increasing elevation.While the soil fertility was relatively high in protected sites as compared to unprotected area.The study shows that protection promotes the growth, distribution and occurrence of medicinal plants.It is possible with the participation of local communities to conserve these resources. 展开更多
关键词 CONSERVATION IN-SITU protected Unprotected ENDANGERED plant SPECIES
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Study on the Current Situation and Protection Countermeasures of Wild Plant Resources in Xishuangbanna National Nature Reserve 被引量:3
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作者 YANG Zhong-xing1, YIN Wu-yuan2, AI Jian-lin1 1. Yunnan Forestry Inventory and Planning Institute, Kunming 650051, China 2. Southwest Forestry University, Kunming 650224, China 《Meteorological and Environmental Research》 CAS 2011年第4期79-82,共4页
[Objective] The aim was to study the current situation and protection countermeasures of wild plant resources in Xishuangbanna National Nature Reserve. [Method] The current situation of wild plant resources in Xishuan... [Objective] The aim was to study the current situation and protection countermeasures of wild plant resources in Xishuangbanna National Nature Reserve. [Method] The current situation of wild plant resources in Xishuangbanna National Nature Reserve was researched by means of route survey, sample plot survey and literature survey, and then the main impact factors of wild plant resources were analyzed by using participatory rural appraisal and problem tree analysis, finally protection countermeasures were put forward according to current situation and main impact factors. [Result] There were 2 779 species of vascular plants belonging to 214 families and 1 012 genera (including subfamilies and varieties) in Xishuangbanna National Nature Reserve, among them, there existed 261 species of pteridophyte belonging to 41 families and 91 genera, 14 species of gymnosperm belonging to 6 families and 6 genera, and 2 504 species of angiosperm belonging to 167 families and 915 genera. Wild plant resources in reserve were mainly affected by planting under forest, habitat fragmentation, cutting trees, collection and utilization of no-timber products, development of animal husbandry, insufficient recognition of community residents to reserve management establishment and lots of floating population. In the future, wild plant resources in reserve could be protected through strengthening propaganda, education and management, enforcing the law strictly and other countermeasures. [Conclusion] The study could provide theoretical foundation for the protection of wild plant resources in Xishuangbanna National Nature Reserve. 展开更多
关键词 Wild plant resources protection countermeasures Impact factors National Nature Reserve XISHUANGBANNA China
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Research of Protected Cultivation Techniques of Toona sinensis on Mountain Slopes 被引量:2
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作者 Qingzhen YIN Chengtong GU +1 位作者 Liyong ZHANG Mingyue GU 《Asian Agricultural Research》 2018年第3期78-82,共5页
In order to prolong the supply period and increase the economic value of Toona sinensis,the protected cultivation of T. sinensis was carried out on mountainous slope to achieve stagger-season planting and the year rou... In order to prolong the supply period and increase the economic value of Toona sinensis,the protected cultivation of T. sinensis was carried out on mountainous slope to achieve stagger-season planting and the year round supply. The results showed that in late October to midNovember,the temperature was moderate( 1-10℃) and suitable for the lifting of seedlings and temporary planting dormancy. The line spacing of rooted seedlings in greenhouse was( 22-24) cm ×( 4-5) cm and planting density was 900 000-1 200 000 seedlings/ha. The line spacing of seedlings was( 14-13) cm ×( 3-4) cm and planting density was 1 950 000-2 100 000 seedlings/ha. T. sinensis began to sprout at 8-10℃ and stretch at 10-12℃. When the temperature was stable at 14℃ or above,T. sinensis started bolting and emerging leaves. The terminal buds sprouted in 40-50 d for the T. sinensis planted in greenhouse with the day temperature of 15-22℃ and night temperature over 10℃; the terminal buds sprouted in about 15 d for those planted in the greenhouse with day temperature of 20-25℃ and night temperature over 10℃. T. sinensis could be picked 3 times when planted in greenhouse,and the yield was about 24 720 kg/ha. 展开更多
关键词 Toona sinensis protected cultivation Temporary planting DORMANCY Cultivation techniques
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Consolidated Lightning Protection Methods of Landfill and Incineration Plants and Its Application Technology Investigation 被引量:1
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作者 Jia Pei Qi Jiuhan Zhu Fanglin 《Meteorological and Environmental Research》 CAS 2017年第5期100-104,共5页
Taking lightning-protection engineering of Wuhan Changshankou landfill and incineration plants for the example,in this article,we have discussed the integrated technology of direct lightning protection by early stream... Taking lightning-protection engineering of Wuhan Changshankou landfill and incineration plants for the example,in this article,we have discussed the integrated technology of direct lightning protection by early streamer emission lightning rod,lifting lightning rod and mobile lightning rod. Additionally,lightning protection methods and measures of landfill with large receiving area of lightning strike and landfill gas and incineration plant with irregular landfill cell are explored. 展开更多
关键词 LANDFILL and INCINERATION plantS LANDFILL gas Consolidated DIRECT LIGHTNING protectION technology
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Urban Garden Planning and Design and Ornamental Plant Protection 被引量:1
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作者 ZHANG Yu 《Journal of Landscape Research》 2018年第4期159-162,共4页
Due to the rapid economic and social development, the quality of life of people has been significantly improved, and peopled demand for living environment has become increasingjy high, which has increased peop... Due to the rapid economic and social development, the quality of life of people has been significantly improved, and peopled demand for living environment has become increasingjy high, which has increased peopled awareness of landscaping. Because of the development of urbankation, however, most cities have lost their balance in the ecological enviionment although they seem to have the modem flavor of life. Integrating garden design with plant protection is an important measure to protect the ecological environment and maintain ecological balance. How to protect the plants in urban garden planning and design has become a problem to be solved by garden designers. In this paper, the relationship between garden design and plant protection was ekbofated, the status quo and problems of ornamental plant protection were analyzed, and measures to protect ornamental plants were proposed. 展开更多
关键词 Landscape planning and design plant protection PROBLEMS SOLUTIONS
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Plant protection: Current status, progress and challenges in China
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作者 WAN Fang-hao 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2019年第4期703-704,共2页
China is one of the countries in the world that is severely damaged by crop diseases,pests,and weeds.There are more than 1 700 species of agricultural pests occurring annually,53 of which are on the list of the 100 wo... China is one of the countries in the world that is severely damaged by crop diseases,pests,and weeds.There are more than 1 700 species of agricultural pests occurring annually,53 of which are on the list of the 100 worst pests in the world(Chen and Wang 2014;Wu 2018).Currently,China is still greatly challenged by a growing problem of agricultural pests that th reate n the economy and health and pose ecological risks underthe conditions of global climate change,economic integration,crop structure adjustment and so on.Plant protect!on agai nst crop diseases,in sect pests and noxious weeds is necessary to ensure high-quality crop production and food safety.However,traditional strategies of plant protect!on have mainly involved chemical pesticides. 展开更多
关键词 plant protection CROP DISEASES AGRICULTURAL PESTS
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Protection and Treatment of Landscape Plant Secondary Disasters (Deicing Agent Damage) Caused by Extreme Weather
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作者 CAO Zhen ZHOU Xue BAI Chao 《Journal of Landscape Research》 2012年第11期61-64,共4页
Deicing agent is always applied to alleviate urban traffic pressure after snowing in winter,however,such a snow melting agent is extremely harmful for landscape plants.To eliminate or avoid such damages,we have been a... Deicing agent is always applied to alleviate urban traffic pressure after snowing in winter,however,such a snow melting agent is extremely harmful for landscape plants.To eliminate or avoid such damages,we have been actively exploring protection and treatment means.By analyzing the protection of landscape plants before using the deicing agent and the treatment after being damaged by the salt,the paper described how landscaping industry of Beijing handled extreme weather and influence of certain urban environment on landscape plants in a high-efficiency and low-cost way,and then figured out the balance point of normal social life and healthy development of ecological environment. 展开更多
关键词 LANDSCAPE plantS DEICING AGENT DAMAGE protection and treatment measures
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Impact of Implementing 1991 Act of the International Convention for the Protection of New Varieties of Plants in China
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作者 YANG Xuhong 《Journal of Northeast Agricultural University(English Edition)》 CAS 2006年第1期90-96,共7页
The Union for the Protection of New Varieties of Plants is abbreviated as UPOV. The Convention for the Protection of New Varieties of Plants has 1961/1972 Act ,1978 Act and 1991 Act. China is member of UPOV and its re... The Union for the Protection of New Varieties of Plants is abbreviated as UPOV. The Convention for the Protection of New Varieties of Plants has 1961/1972 Act ,1978 Act and 1991 Act. China is member of UPOV and its regulations of protection of new varieties of plants conform to 1978 Act. At present, there is big debate whether China accedes to 1991 Act. This paper mainly discussed advantages and possibilities that China accedes to 1991 Act, and concluded that it is highly desirable that China should consider acceding to 1991 Act in order to contribute to development of system on protection of new varieties of plants. 展开更多
关键词 protection of new varieties of plants UPOV convention China
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Farmers' Privilege under the Protection of New Plant Varieties
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作者 YANG De-xing Department of Human Sciences,Suzhou Polytechnic Institute of Agriculture,Suzhou 215008,China 《Asian Agricultural Research》 2012年第7期86-88,共3页
This paper studies farmers'privilege under the protection of new plant varieties,and points out that farmers'privilege is given to balance interests of plant breeders and relevant public.Based on this,it analy... This paper studies farmers'privilege under the protection of new plant varieties,and points out that farmers'privilege is given to balance interests of plant breeders and relevant public.Based on this,it analyzes shortcomings of farmers'privilege regulations,and puts forward that it is required to improve farmers'privilege regulations in subjects,objects and contents of rights on the basis of learning from advanced legislation experience of foreign countries,and build the interest sharing mechanism between breeders and farmers. 展开更多
关键词 protectION of NEW plant VARIETIES Farmers’privileg
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Some Technical Solutions for Environmental Protection System during Accidents at Nuclear Power Plants
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作者 Sergey A. Kulyukhin Igor’ A. Rumer +5 位作者 Viktor M. Berkovich Gennadii S. Taranov Ivan V. Yagodkin Viktor P. Osipov Sergey S. Skvortsov Leo N. Falkovskii 《World Journal of Engineering and Technology》 2017年第4期1-11,共11页
The paper reports some technical solutions, which suggested or used for increasing of environmental protection during accidents at NPPs. For NNPs with two protective shells and pressure release system such as WWER-100... The paper reports some technical solutions, which suggested or used for increasing of environmental protection during accidents at NPPs. For NNPs with two protective shells and pressure release system such as WWER-1000 a comprehensive, passive-mode environmental protection system of decontamination of the radioactive steam-air mixture from the containment and the intercontainment area was suggested. This system includes the “wet” stage (scrubbers, etc.), the “dry” stage (sorption module), and also an ejector, which in a passive mode is capable of solving the multi-purpose task of decontamination of the air-steam mixture. For WWER-440/230 NPPs three protection levels: 1) a jet-vortex condenser;2) the spray system;3) a sorption module were suggested and installed. For modern designs of new generation NPPs, which do not provide for pressure release systems, a new passive filtering system together with the passive heat-removal system, which can be used during severe accidents in case all power supply units become unavailable, was proposed and after modernization was installed at the KudanKulam NPP (India). 展开更多
关键词 NUCLEAR Power plantS SEVERE ACCIDENT Environment protection RADIOACTIVE Steam-Air Phase
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Photoprotective Effects of D1 Protein Turnover and the Lutein Cycle on Three Ephemeral Plants under Heat Stress
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作者 Minmin Xiao Moxiang Cheng +3 位作者 Shuangquan Xie Xiushuang Wang Xingming Hao Li Zhuang 《Phyton-International Journal of Experimental Botany》 SCIE 2023年第6期1841-1857,共17页
To clarify the characteristics of photoinhibition and the primary defense mechanisms of ephemeral plant leaves against photodestruction under high temperature stress,inhibitors and the technology to determine chloroph... To clarify the characteristics of photoinhibition and the primary defense mechanisms of ephemeral plant leaves against photodestruction under high temperature stress,inhibitors and the technology to determine chlorophyll fluorescence were used to explore the protective effects of D1 protein turnover and the lutein cycle in the high temperature stress of the leaves of three ephemeral plants.The results showed that the maximum light conversion efficiency(Fv/Fm)of the ephemeral plant leaves decreased,and the initial fluorescence(Fo)increased under 35℃±1℃ heat stress for 1-4 h or on sunny days in the summer.Both Fv/Fm and Fo could be recovered after 8 h of darkness or afternoon weakening of the external temperature.Streptomycin sulfate(SM)or dithiothreitol(DTT)accelerated the decrease of Fv/Fm and the photochemical quenching coefficient(qP)in the leaves of three ephemeral plants at high temperature,and the decrease was greater in the SM than in the DTT treatment.When the high temperature stress was prolonged,the Y(II)values of light energy distribution parameters of PSII decreased,and the Y(NPQ)and Y(NO)values increased gradually in all the treatment groups of the three ephemeral plants.The results showed that the leaves of the three ephemeral plants had their own highly advanced mechanisms to protect against photodamage,which inhibited the turnover of D1 protein and xanthophyll cycle.This can damage the PSII reaction center in the leaves of the three ephemeral plants under high temperature.The protective effect of D1 protein turnover on heat stress in Erodium oxyrrhynchum and Senecio subdentatus was greater than that of the lutein cycle,while the protective effect of lutein cycle was greater than that of D1 protein turnover in Heliotropium acutiflorum subjected to heat damage. 展开更多
关键词 D1 protein lutein cycle ephemeral plants light inhibition light protection
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Time-Domain Protection for Transmission Lines Connected to Wind Power Plant based on Model Matching and Hausdorff Distance
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作者 Hongchun Shu Xiaohan Jiang +3 位作者 Pulin Cao Na An Xincui Tian Bo Yang 《Energy Engineering》 EI 2021年第1期53-71,共19页
The system impedance instability,high-order harmonics,and frequency offset are main fault characteristics of wind power system.Moreover,the measurement angle of faulty phase is affected by rotation speed frequency co... The system impedance instability,high-order harmonics,and frequency offset are main fault characteristics of wind power system.Moreover,the measurement angle of faulty phase is affected by rotation speed frequency component,which causes traditional directional protections based on angle comparison between voltage and current to operate incorrectly.In this paper,a time-domain protection for connected to wind power plant based on model matching is proposed,which compares the calculated current and the measured current to identify internal faults and external faults.Under external faults,the calculated current and measured current waveform are quite similar because the protected transmission lines is equivalent to a lumped parameter model and the model itself is not damaged.However,the similarity of calculated current and measured current is quite low,due to destroyed integrity of model under internal faults.Additionally,Hausdorff distance is introduced to obtain the similarity of the calculated current and measured current.Since the proposed protection scheme is applied in time domain,it is independent from current frequency offsets of wind energy system,high-order harmonics,and system impedance variations.Comprehensive case studies are undertaken through Power Systems Computer Aided Design(PSCAD),while simulation results verify the accuracy and efficiency of the proposed approach in fault identification. 展开更多
关键词 Wind power plant CROWBAR time-domain protection hausdorff distance model matching
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Particle Kinematics Analysis of Droplet Drift in Spraying Operation of Plant Protection UAV
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作者 Xiong ZOU Rangshu XU +1 位作者 Jingchun LI Zilin LIU 《Plant Diseases and Pests》 CAS 2022年第2期17-20,23,共5页
[Objectives]The paper was to study the effect of droplet drift on spray quality of plant protection UAV.[Methods]Based on the theory of multiphase flow and the method of particle kinematics,the force and motion trajec... [Objectives]The paper was to study the effect of droplet drift on spray quality of plant protection UAV.[Methods]Based on the theory of multiphase flow and the method of particle kinematics,the force and motion trajectory of droplet sprayed by plant protection UAV were theoretically analyzed and mathematically modeled.On the basis of the assumption of wind speed in the ground layer and the laminar sublayer,that is,it is assumed that the wind speed in the area of wind measurement was approximately a linear distribution,the coupling iterative solution of the equations was carried out.The influence of droplet diameter,flight height,flight speed of plant protection UAV,course angle,wind speed,wind direction,initial droplet velocity and direction of initial velocity on droplet drift were analyzed.The influence of the coupling effect of each factor on droplet drift was further discussed and the distribution of droplet drift concentration was obtained.[Results]The wind speed and direction had much influence on the drift distance of droplets,and the drift distance and the initial velocity angle show a quadratic function distribution.Under the given conditions,the drift distance was the closest when the initial velocity angle was about 20°.The droplet drift was mainly distributed scatteredly around the nozzle.[Conclusions]The study provides a reference for improving the spraying quality of plant protection UAV. 展开更多
关键词 plant protection UAV Droplet drift Particle kinematics Concentration distribution COUPLING
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