青海柴达木盆地气候生态资源特点和农业开发

柴达木盆地位于青海高原西北部,面积为2.5×10~5km~2,海拔3000m,周围山系海拔5400—6000m,较毗邻新疆塔里木盆地高2000m 左右,为我国海拔最高的内陆高原盆地。有可利用草场约6.67×10~6ha。耕地约6.0×10~4ha,作物主要为春小麦,分布于东南和东北部荒漠绿     

豫西农业发展的现状,问题与未来

一、自然背景与发展特征豫西地区属黄土高原的东延部分,总面积约2.68×10~4km~2,共有耕地8.0×10~5ha多,是河南省典型的丘陵山区,亦是河南省重要的农业生产基地。本区地处暖温带,气候具有明显的大陆性半干旱特征。年降雨量稍高于晋陕黄土高原,多在500—900mm之间,但年际差异大,年内雨量分配不均;山区常年平均温度6—12℃,丘陵和河谷阶地12—14℃,水热资源尚属丰富,适宜农业发展。这里的农业从以放牧形式     

安徽涡阳县桐农间作类型及其效益分析

一、概况涡阳县位于黄淮平原南部,安徽省的西北部。全县土地面积2.09×10~5ha,其中耕地面积1.44×10~5ha。人口105万。本县属暖温带半湿润季风气候区,年平均气温14.6℃,降水量824mm,蒸发量1974.5mm。太阳辐射总量5.22×10~5J·m~(-2)。气候温和,水热同季,     

对水旱轮作农业生态效应的探讨

多年来,人们对水旱轮作的增产效果和经济效益有很多研究,但对它的生态效益研究不多。其实,水旱轮作之所以增产,产生巨大的经济效益,其根源还是水旱轮作所带来的良好的生态效益所致。本文从生态效应的角度,初步探讨了水旱轮作的增产原因。一、综合治理“水袋子”,大力开展水旱轮作1.开展水旱轮作,促进粮棉高产稳产全县现有耕地7.087×10~4ha,其中稻田4.197×10~4ha;棉田1.607×10~4ha。利用本县丰富的水资源(年客水量1.36×10~9m~3),根据农田生产线基本平行于水位线的特点,1970年开始实行水旱轮作,随着水利条件的逐     

充分利用福建滨海沙滩植被资源发展种植业

福建滨海沙滩位于北纬23°37′—27°10′范围,面积约5.33×10~4ha,已植防护林近2.0×10~4ha,尚约有3.34×10~4ha 未开发利用,其中分布于闽江口以南岸段和岛屿约2.86×10~4ha,     

生态环境与汾河水库输沙量的灰色关联分析和预测

汾河水库1960年开始拦洪,设计总库容量为7.2×10~7m~3。它担负着太原市的防洪、工业用水和1.0×10~5ha 的农田灌溉。水库上游包括宁武、静乐、岚县、娄烦四县,总流域面积为5268km~2。年平均降水量450—500mm,其中汛期降水占全年降水量的70—80%。建库前,多年平均输沙量达2.105×10~7m~3,年侵蚀模数     

黄淮海平原高产田作物群体结构特征

本文利用实测资料分析了高产田作物群体结构特征。精播高产栽培麦田春季最大蘖数12×10~6/ha,群体最大叶面积指数5.5—6.0,成穗4.5—5.25×10~6/ha。传统高产栽培麦田春季最大蘖数15—18×10~6/ha,群体最大叶面积指数6.0—6.5,成穗6.0—7.5×10~6/ha。小麦营养生长与生殖生长期叶日积比,精播高产栽培麦田是1∶0.89,传统高产栽培麦田为1∶0.73。夏玉米种植密度主要受叶倾角的影响。紧凑型玉米品种的叶倾角大于65°,种植密度7.5—8.25×10~4/ha;平展型玉米品种的叶倾角小于50°,种植密度5.25—6.0×10~4/ha。     

林业生产中的生物固氮利用

据统计,全球每年生物固氮总量约为175×10~6t(吨)。其中耕地固氮量达44×10~6t;全球林地面积约41×10~6hm~2(公顷),其固氮总量也可达40×10~6t;而全世界每年工业生产的氮肥约60×10~6t。可见生物固氮在农业和林业生产上的规模和作用是很大的。有关生物固氮与农业的关系已有人作了专题论述,本文专就固氮与林业的关系谈些看法。     

论吉林省中部玉米带的气候生态适应性

玉米是吉林省的主要作物之一,其产量占全省粮食总产量的60%以上,产值占全省农业总产值的1/3以上。吉林省中部地区13个县是玉米的主要产区,总耕地面积2.267×10~6ha,占全省的56%,1985年中部玉米面积1.0×10~6ha,占中部耕地面积的44%,占全省玉米面积     

总结旱地农业经验加强农业生态建设

河北省武安市位于太行山东麓,山多地少,丘陵起伏,沟壑纵横。总面积1806km~2,耕地6.2×10~4ha,其中60%以上分布在丘陵山地。境内地势倾斜,高差较大,西部最高海拔1898m,东部最低海拔仅92m。荒山植被稀疏,水土流失严重。平均年降水量529mm,季节分     

Internal model control for structured rank deficient system based on full rank decomposition

In this paper, an internal model control method is first proposed for structured rank deficient systems based on full rank decomposition. The system is first converted into a column full rank system by designing a pre-compensator. Then a feedback-compensator is designed to improve the dynamic characteristics of the full rank system and decrease the controller design difficulties. Rather than performing complex designing calculations, the pre- and feedback- compensators are designed by the full rank decomposition method. Furthermore, the non-square relative gain subsystem selection criterion is used to choose the square subsystem and to realize loop pairing. Consequently, the selected square subsystem is used as an internal model to design the internal model controller. Finally, a simple process is taken as the simulation object to demonstrate the validity and feasibility of the new method. Simulations results illustrate that the proposed strategy is not only simple and easy to implement but also has a good performance even the system model is mismatched.     

氢离子选择性微电极细胞内pH测量系统的研制

本文叙述我们建立的以 IBM PC/XT 兼容机为核心的细胞内 pH 值的测量系统。着重说明对氢离子敏感的离子选择性微电极的制作方法,与其连接的极高输入阻抗的微电极放大器的设计,以及为提高测量的精度而采取的多种措施。阐述了系统的性能、并对其测量精度、优缺点进行了分析与讨论。     

Optimization of biochemical systems by linear programming and general mass action model representations

A new method is proposed for the optimization of biochemical systems. The method, based on the separation of the stoichiometric and kinetic aspects of the system, follows the general approach used in the previously presented indirect optimization method (IOM) developed within biochemical systems theory. It is called GMA-IOM because it makes use of the generalized mass action (GMA) as the model system representation form. The GMA representation avoids flux aggregation and thus prevents possible stoichiometric errors. The optimization of a system is used to illustrate and compare the features, advantages and shortcomings of both versions of the IOM method as a general strategy for designing improved microbial strains of biotechnological interest. Special attention has been paid to practical problems for the actual implementation of the new proposed strategy, such as the total protein content of the engineered strain or the deviation from the original steady state and its influence on cell viability.     

一种模拟昆虫视觉系统并行信息处理功能的光学实现

本文提出了一种新的模拟生物视觉神经系统并行信息处理功能的光学方法,它采用了昆虫复眼透镜阵列处理器和非相干光源实现图像矩阵正交变换,它为光神经计算提供了一种可能实现的新途径.     

Genome editing system CRISPR/CAS9 and peculiarities of its application in monocots

Genome editing is a new methodology for DNA modification that has been developing in recent years. This review compares proposed methods of optimization and development of a modern genome editing system—CRISPR/Cas9—in monocots. Methodical approaches for in silico selecting target sites, designing an expression vector, transferring the vector expression cassette into plant cells, evaluating the results of the editing and nonspecific activity of the system, and obtaining modified plants free of foreign DNA are reviewed. The problem of legislative regulation and the prospects for using this method for commercial purposes are discussed.     

发酵过程中细胞浓度在线检测系统*

利用微机软、硬件技术,设计了一套比浊法细胞浓度在线检测系统,并应用于5L发酵罐中木糖醇发酵过程细胞浓度在线检测。该系统能及时、较准确地反映发酵过程中菌体浓度随时间的变化情况,在规模化生产中具有较强的适用性、通用性,可为实现其它分析仪器的计算机在线检测系统提供值得借鉴的设计思路和实现方法。     

庭园生态经济系统设计及应用

庭园生态经济系统设计及应用刘东飙邓立平（湖南省益阳市农村能源办公室４１３０００）（湖南省南县农村能源办公室４１３２００）ＤｅｓｉｇｎｉｎｇＯｆＨｏｍｅＧａｒｄｅｎＥｃｏｌｏｍｉｃＳｙｓｔｅｍｗｉｔｈＭｅｔｈａｎｅＧｅｎｅｒａｔｉｎｇａｓａＴｉｅａｎｄ...     

Design of ant-inspired stochastic control policies for collective transport by robotic swarms

In this paper, we present an approach to designing decentralized robot control policies that mimic certain microscopic and macroscopic behaviors of ants performing collective transport tasks. In prior work, we used a stochastic hybrid system model to characterize the observed team dynamics of ant group retrieval of a rigid load. We have also used macroscopic population dynamic models to design enzyme-inspired stochastic control policies that allocate a robotic swarm around multiple boundaries in a way that is robust to environmental variations. Here, we build on this prior work to synthesize stochastic robot attachment–detachment policies for tasks in which a robotic swarm must achieve non-uniform spatial distributions around multiple loads and transport them at a constant velocity. Three methods are presented for designing robot control policies that replicate the steady-state distributions, transient dynamics, and fluxes between states that we have observed in ant populations during group retrieval. The equilibrium population matching method can be used to achieve a desired transport team composition as quickly as possible; the transient matching method can control the transient population dynamics of the team while driving it to the desired composition; and the rate matching method regulates the rates at which robots join and leave a load during transport. We validate our model predictions in an agent-based simulation, verify that each controller design method produces successful transport of a load at a regulated velocity, and compare the advantages and disadvantages of each method.     

Diffusion of DNA Molecules in Gel at High Electric Fields

Problems related to the gel electrophoretic migration of polymers can be investigated by models based on a Brownian-type ratchet where a particle can undergo a net transport on a potential energy surface that is externally driven to fluctuate between several distinct states. Here we describe the method of polymer transport and separation by means of the cellular automata technique. Numerical simulations of the polymer reptation in the model system allow us to understand the band-broadening processes in the gel electrophoresis experiments. They indicate also possible ways of fine-tuning the parameters in designing desired resolution of the experiments.     

油菜播栽方案设计的动态知识模型

运用知识工程和系统建模方法,在总结、归纳和提炼油菜生长发育与生态环境、品种类型、生产技术水平和产量目标关系的基础上,建立了具有时空适应性的油菜播栽方案设计的动态知识模型,可用于精确定量不同环境和生产条件下油菜品种的适宜播期、基本苗、播种量和移栽方案.利用南京、郑州和保定3个地点的常年逐日气象资料以及各点不同品种和播种方式资料对播栽方案设计模型进行实例分析,结果表明,该知识模型对播期和基本苗设计均具有较好的决策性、解释性和适用性.