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宁夏盐池县人地关系的演变及调适对策 被引量:6
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作者 王磊 宋乃平 《资源科学》 CSSCI CSCD 北大核心 2007年第6期138-145,共8页
对宁夏盐池县人地关系中的"人"子系统和"地"子系统进行了分析研究。"人"子系统的研究主要从人口数量、人口质量和人类行为3个方面着手;"地"子系统的研究主要从土地利用、耕地变化和地表植被变... 对宁夏盐池县人地关系中的"人"子系统和"地"子系统进行了分析研究。"人"子系统的研究主要从人口数量、人口质量和人类行为3个方面着手;"地"子系统的研究主要从土地利用、耕地变化和地表植被变化3个方面着手。地表植被状况的变化用遥感卫星影像的归一化植被指数NDVI(normalized difference vegetation index)来综合反映。进而再运用相关分析法研究盐池县"人"子系统和"地"子系统的相互作用关系,并总结了其演变过程。分析发现宁夏盐池县人地关系系统存在的问题主要是:人口文化素质仍较差,劳动力文化水平偏低;掠夺式的人类行为导致"地"子系统的不断退化。进而相应提出了控制人口增长,加大劳动力转移力度,以减轻人口压力;提高种植业整体水平;通过合理的草地利用方式,从根本上缓解人地矛盾;多能互补,解决能源问题等调适对策。 展开更多
关键词 人地关系 “人”子系统 “地”子系统 NDVI 盐池县
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Phytate:impact on environment and human nutrition.A challenge for molecular breeding 被引量:34
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作者 Lisbeth BOHN Anne S. MEYER Sren K. RASMUSSEN 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2008年第3期165-191,共27页
Phytic acid (PA) is the primary storage compound of phosphorus in seeds accounting for up to 80% of the total seed phosphorus and contributing as much as 1.5% to the seed dry weight. The negatively charged phosphate i... Phytic acid (PA) is the primary storage compound of phosphorus in seeds accounting for up to 80% of the total seed phosphorus and contributing as much as 1.5% to the seed dry weight. The negatively charged phosphate in PA strongly binds to metallic cations of Ca, Fe, K, Mg, Mn and Zn making them insoluble and thus unavailable as nutritional factors. Phytate mainly accumulates in protein storage vacuoles as globoids, predominantly located in the aleurone layer (wheat, barley and rice) or in the embryo (maize). During germination, phytate is hydrolysed by endogenous phytase(s) and other phosphatases to release phosphate, inositol and micronutrients to support the emerging seedling. PA and its derivatives are also implicated in RNA export, DNA repair, signalling, endocytosis and cell vesicular trafficking. Our recent studies on purification of phytate globoids, their mineral composition and dephytinization by wheat phytase will be discussed. Biochemical data for purified and characterized phytases isolated from more than 23 plant species are presented, the dephosphorylation pathways of phytic acid by different classes of phytases are compared, and the application of phytase in food and feed is discussed. 展开更多
关键词 PHYTASE Phytic acid Iron bioavailability Antinutritional factor Purple acid phosphatase CEREAL
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Quantum Anti-Zeno Effect in Artificial Quantum Systems 被引量:1
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作者 艾清 廖洁桥 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第12期985-996,共12页
In this paper, we study a quantum anti-Zeno effect (QAZE) purely induced by repetitive measurements for an artificial atom interacting with a structured bath. This bath can be artificially realized with coupled reso... In this paper, we study a quantum anti-Zeno effect (QAZE) purely induced by repetitive measurements for an artificial atom interacting with a structured bath. This bath can be artificially realized with coupled resonators in one dimension and possesses photonic band structure like Bloeh electron in a periodic potential. In the presence of repetitive measurements, the pure QAZE is discovered as the observable decay is not negligible even for the atomic energy level spacing outside of the energy band of the artificial bath. If there were no measurements, the decay would not happen outside of the band. In this sense, the enhanced decay is completely induced by measurements through the relaxation channels provided by the bath. Besides, we also discuss the controversial golden rule decay rates originated from the van Hove's singularities and the effects of the counter-rotating terms. 展开更多
关键词 quantum Zeno effect quantum anti-Zeno effect artificial quantum system
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A hybrid neural network system for prediction and recognition of promoter regions in human genome 被引量:1
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作者 陈传波 李滔 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2005年第5期401-407,共7页
This paper proposes a high specificity and sensitivity algorithm called PromPredictor for recognizing promoter regions in the human genome. PromPredictor extracts compositional features and CpG islands information fro... This paper proposes a high specificity and sensitivity algorithm called PromPredictor for recognizing promoter regions in the human genome. PromPredictor extracts compositional features and CpG islands information from genomic sequence,feeding these features as input for a hybrid neural network system (HNN) and then applies the HNN for prediction. It combines a novel promoter recognition model, coding theory, feature selection and dimensionality reduction with machine learning algorithm.Evaluation on Human chromosome 22 was ~66% in sensitivity and ~48% in specificity. Comparison with two other systems revealed that our method had superior sensitivity and specificity in predicting promoter regions. PromPredictor is written in MATLAB and requires Matlab to run. PromPredictor is freely available at http://www.whtelecom.com/Prompredictor.htm. 展开更多
关键词 Hybrid neural network Promoter prediction Compositional features CpG islands
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The decision-making dimension of the systems approach to management
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作者 James Kennedy Turkson 《Chinese Business Review》 2010年第2期27-33,共7页
Theoretically, a system is anything that is made up of various parts. Theses parts are known as subsystems. At every point in time, these parts should work in harmony so that objectives could be achieved successfully.... Theoretically, a system is anything that is made up of various parts. Theses parts are known as subsystems. At every point in time, these parts should work in harmony so that objectives could be achieved successfully. A system could be inanimate or animate item. Examples of inanimate systems include vehicles, households, computer and institution. Examples of animate systems are human being, animal and insect. Both inanimate and animate systems are made up of various subsystems. Such subsystems are required to co-operate, collaborate and work together so that set objectives could be achieved successfully. From practical managerial point of view, business organizations are equally systems that are made up of subsystems which may take the form of departments, sections and/or units. It is supposed to be collaborations among the managers and other members in these departments, sections and/or units so that organizational objectives could be achieved. All the managers in various departments, sections and/or units are required to work together as a team to make the system coherent and closely-knit to make disintegration impossible. Closely related to the systems approach to management is managerial decision-making. Decision-making is a very important function of every manager's job. The success and failure stories of many organizations are the result of the quality of decisions made. Many organizations have survived turbulent conditions. Others have also collapsed in spite of favourable conditions. These varying conditions are the result of the quality of decisions made by managers at positions of authority and responsibility. Therefore the systems approach to management enjoins top managers in particular to be very circumspect and cautious in certain decision-making activities. This is because, the quality of decision a manager makes can go a long way to determine the success or failure story of an organization as exemplified in the case study in this paper. 展开更多
关键词 system sub-system SYNERGY open-system closed-system MANAGEMENT decision-making
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Children witness a systematic research
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作者 Li Yang 《International English Education Research》 2014年第6期13-15,共3页
in China, children witness has not been articled in three procedural laws, some scholar do not think that either children nor other person with no legal capacity should have witness qualification.in fact, although som... in China, children witness has not been articled in three procedural laws, some scholar do not think that either children nor other person with no legal capacity should have witness qualification.in fact, although some other countries do not admit the qualification of children witnesses under certain age,they do not take it as the factor to measure whether a witness has qualification or not.It is the judge who can decide whether a witness has qualification or not.Based on the these foreign counlries' s experience,we should not limit the qualification of children witnesses in the legislation. However, for the particularity of children's cognitive ability,we should embody this particularity when we judge children's testimony and protect children witnesses. 展开更多
关键词 Children witness witness qualification witness protection testimony scrutiny
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The Contribution of Artificial Intelligence Tools in Screening for Cancer of the Cervix
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作者 Guesmi Lamia Nabli Lotfi Bedoui Mohamed Hedi 《Computer Technology and Application》 2011年第6期479-486,共8页
Recently, research into pathological cytology were intended to put in places of artificial intelligence systems based on the development of new diagnostic technologies and the cell image segmentation. These technologi... Recently, research into pathological cytology were intended to put in places of artificial intelligence systems based on the development of new diagnostic technologies and the cell image segmentation. These technologies are not intended to substitute the human expert but to facilitate his task. The objective of this work is to develop a method for diagnosing cancer cervical smears using cervical-vaginal segmented to build the authors' database and a human supervisor and as an automatic tool manage and monitor the execution of the operation of diagnostic and proposing corrective actions if necessary. The Supervisor Smart is manufactured by the technique of neural networks with a success rate of 43.3% followed by the technique of fuzzy logic with a success rate equal to 56.7% and finally to improve this rate we used neuro-fuzzy approach which has a rate which reaches 94%. 展开更多
关键词 Cervical smear-vaginal (CSV) artificial intelligence SUPERVISOR fuzzy logic neural networks
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Children witness --a systematic research
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作者 Li Yang 《International English Education Research》 2014年第7期40-42,共3页
In China, children witness has not been articled in three procedural laws, some scholar do not think that either children nor other person with no legal capacity should have witness qualification.In fact, although som... In China, children witness has not been articled in three procedural laws, some scholar do not think that either children nor other person with no legal capacity should have witness qualification.In fact, although some other countries do not admit the qualification of children witnesses under certain age, they do not take it as the factor to measure whether a witness has qualification or not. It is the judge who can decide whether a witness has qualification or not. Based on the these foreign countries's experience, we should not limit the qualification of children witnesses in the legislation. However, for the particularity of children's cognitive ability, we should embody this particularity when we judge children's testimony and protect children witnesses. 展开更多
关键词 Children witness witness qualification witness protection testimony scrutiny
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Above-ground Biomass Allocation in a Planted Forest in a Semi-arid Region of Northern Mongolia
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作者 Sukhbaatar Gerelbaatar Nachin Baatarbileg 《Journal of Agricultural Science and Technology(B)》 2013年第3期216-220,共5页
Investigation of the above-ground biomass allocation patterns on Scots pine plantations is critical for quantifying the productivity and carbon cycle of forest ecosystems. We estimated above-ground biomass and net pri... Investigation of the above-ground biomass allocation patterns on Scots pine plantations is critical for quantifying the productivity and carbon cycle of forest ecosystems. We estimated above-ground biomass and net primary production of a 25-year-old Pinus sylvestris L. (Scots pine) plantation, in a semi-arid region of Mongolia. The above-ground biomass of sample trees was divided into stem wood, stem bark, live branches, dead branches and needles. Total biomass for the stand was only 18.03 Mg ha1, of which 47.6% was found in stem wood, 25.8% in live branches and 14.8% in needles. The growth rate of the Scots pine plantation in the study region was relatively low compared with other regions. In the study area, it was observed that the rate of biomass accumulation in the plantation was very slow; this can be explained by very limited growing conditions and intensive crown closure. The results from this study indicate that it may be necessary to carry out thinning to increase biomass production by reducing competition between trees in the Scotch pine plantation. 展开更多
关键词 Biomass allocation dry biomass Scots pine plantation PRODUCTIVITY forest ecosystems.
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New advances in complex motion control for single robot systems and multi-agent systems 被引量:2
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作者 FANG Hao LU Shao Lei CHEN Jie 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2016年第12期1963-1964,共2页
CHEN Jie,email:chenjie@bit.edu.cn
关键词 robot advances email cooperation simplified decomposed scenarios classic climbing obstacles
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Grid systems for geographic modelling and simulation:A review 被引量:3
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作者 CHEN Min LU Guo Nian +1 位作者 LU FuQiang WAN Gang 《Science Foundation in China》 CAS 2018年第3期47-68,共22页
Geography requires a comprehensive understanding of both natural and human factors,as well as their interactions.Due to the complexity and multiplicity of geographic problems,various theories and methods for geographi... Geography requires a comprehensive understanding of both natural and human factors,as well as their interactions.Due to the complexity and multiplicity of geographic problems,various theories and methods for geographic modelling and simulation have been proposed.Currently,geography has entered an era in which quantitative analysis and modelling are essential for understanding the mechanisms of geographic processes.As the basic idea of quantitative spatial analysis,the specified space often needs to be partitioned by a series of small computational units(cells),i.e.,grids.Thus,there is a close relationship between the grids and geographic modelling.This article reviews the mainstream and typical grids used for modelling and simulation.In addition to classification,the derived theories and technologies,including grid generation methods,data organization strategies,multi-dimensional querying methods,and grid adaptation techniques,are discussed.For integrated geographic simulation to explore comprehensive geographic problems,we argued that it is reasonable to build bridges among different types of grids(e.g.,transformation strategies),and more powerful grids that can support multi-type of numerical computation are urgently needed. 展开更多
关键词 Geographic modelling and simulation Grid system Grid classification Grid construclion Numerical methods.
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Trophallaxis network control approach to formation flight of multiple unmanned aerial vehicles 被引量:17
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作者 DUAN HaiBin LUO QiNan YU YaXiang 《Science China(Technological Sciences)》 SCIE EI CAS 2013年第5期1066-1074,共9页
A novel network control method based on trophaUaxis mechanism is applied to the formation flight problem for multiple un- manned aerial vehicles (UAVs). Firstly, the multiple UAVs formation flight system based on tr... A novel network control method based on trophaUaxis mechanism is applied to the formation flight problem for multiple un- manned aerial vehicles (UAVs). Firstly, the multiple UAVs formation flight system based on trophallaxis network control is given. Then, the model of leader-follower formation flight with a virtual leader based on trophallaxis network control is pre- sented, and the influence of time delays on the network performance is analyzed. A particle swarm optimization (PSO)-based formation controller is proposed for solving the leader-follower formation flight system. The proposed method is applied to five UAVs for achieving a 'V' formation, and a series of experimental results show its feasibility and validity. The proposed control algorithm is also a promising control strategy for formation flight of multiple unmanned underwater vehicles (UUVs), unmanned ground vehicles (UGVs), missiles and satellites. 展开更多
关键词 unmanned aerial vehicle (UAV) trophaHaxis network control formation flight particle swarm optimization (PSO)
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Half-lives of double β^+-decay with two neutrinos
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作者 REN YueJiao REN ZhongZhou 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2015年第1期38-41,共4页
Nuclear double β^--decays with two neutrinos were observed for many years and a systematic law describing the relation between their half-lives and decay energies was also proposed recently [Phys Rev C, 2014, 89: 06... Nuclear double β^--decays with two neutrinos were observed for many years and a systematic law describing the relation between their half-lives and decay energies was also proposed recently [Phys Rev C, 2014, 89: 064603]. However, double β^+ -decay (β^+β^+) with emission of both two positrons and two neutrinos has not been observed up to date. In this article, we pcrform a systematic analysis on the candidates of double β^+-decay, based on the 2012 nuclear mass table. Eight nuclei are found to be the good candidates for double β^+-decay and their half-lives are predicted according to the generalization of the systematic law to double β^+-decay. As far as we know, there is no theoretical result on double β^+-decay of nucleus ^154Dy and our result is the first prediction on this nucleus. This is also the first complete research on eight double β^+-decay candidates based on the available data of nuclear masses. It is expected that the calculated half-lives of double β^+-decay in this article will be useful for future experimental search of double β^+-decay. 展开更多
关键词 double β^+-decay with two neutrinos HALF-LIVES systematic law weak interaction.
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Non-Markovian Master Equation for Distant Resonators Embedded in a One-Dimensional Waveguide
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作者 Xin-Yu Chen Wen-Zhao Zhang Chong Li 《Communications in Theoretical Physics》 SCIE CAS CSCD 2018年第9期273-279,共7页
We develop a master equation approach to describe the dynamics of distant resonators coupled through a one-dimensional waveguide. Our method takes into account the back-actions of the reservoirs, and enables us to cal... We develop a master equation approach to describe the dynamics of distant resonators coupled through a one-dimensional waveguide. Our method takes into account the back-actions of the reservoirs, and enables us to calculate the exact dynamics of the complete system at all times. We show that such system can cause nonexponential and long-lived photon decay due to the existence of a relaxation effect. The physical origin of non-Markovianity in our model system is the finite propagation speed resulting in time delays in communication between the nodes, and strong decay rate of the emitters into the waveguide. When the distance satisfies the standing wave condition, we find that when the time delay is increased, the dark modes formation is no longer perfect, and the average photon number of dark mode decreases in steady time limit. 展开更多
关键词 non-Markovian master equation quantum network waveguide QED
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