池塘底质改良机的研制

为了解决池塘养殖底泥大量沉积引起的水质恶化和鱼病爆发的问题,设计了一种适用于养殖期间对底质进行调控的池塘底质改良机。该机采用太阳能为系统提供动力,可将底泥搅动后提升到上层水体中再利用,并能够实现在水面有规律、可控的运动。在对整机尺寸、提水量、工作半径、光照强度、静水航速等参数进行预期设定的基础上,完成了池塘底质改良机的设计,并阐述了该机的总体机构及底泥提升装置、动力装置、水面行走装置和控制系统4大核心部件的工作原理。对池塘底质改良机的工作覆盖率、提水量、空载噪声、水面行走装置移动速度、底泥提升装置前进速度、无线遥控距离进行了测试,各项指标均满足设计要求。池塘底质改良机工作安全可靠,能够促进底质营养盐的释放,达到调控底泥的目的。     

池塘养殖沉积物收集装置的研制

为解决池塘固定沉积物集中收集的问题,设计了池塘养殖沉积物收集装置,主要由吸污装置、行走机构、控制系统和输泥管系组成。吸污装置利用污水泵将池塘底部的沉积物提升到岸上;行走机构的直流推进器为装置提供动力,实现自主行走;控制系统通过控制污水泵和两个推进器的工作状态,实现装置的运行。性能测试表明:沉积物收集装置在吸污作业时,行进速度需控制在0. 1 m/s以内,清淤时间在20～40 s范围内,可将固定点的沉积物完全吸除;吸污能力在0～14 m~3/h范围内,沉积物含泥量在0～12. 7 m~3/h范围内,沉积物浓度在0～35%范围内;整机配套功率为0. 9 kW,输送距离为100 m,空载噪声为52 dB。池塘养殖沉积物收集装置利用220 V的交流电作为电源,并采用隔离变压器与电网隔离后,再输送至池塘养殖沉积物收集装置的控制平台,安全性高,在池塘水体中运行范围大,实现了池塘养殖沉积物的集中收集。     

A simple kinetic model of polymer adsorption and desorption

A model of the desorption and adsorption of a polymer layer at a planar surface indicates a transition from exponential kinetics at high temperatures to nonexponential kinetics (stretched exponential with index one-half) at lower temperatures where these processes are diffusion-limited. Measurements of polystyrene desorption through polyisoprene overlayers show this predicted transition. Corroborative results are obtained for polystyrene desorption through polymethylmethacrylate overlayers. This identification of two distinct kinetic regimes suggests a unifying perspective from which to analyze polymer and biopolymer mobility at surfaces.     

分块逆M-矩阵的一个性质

从逆M-矩阵具有幂不变的零位模式出发,获得了分块逆M-矩阵的一个性质.     

基于神经网络和遗传算法的池塘溶解氧预测模型

水产养殖池塘是一个多变量、非线性和大时延系统,其中溶解氧的预测也是一个复杂的问题。针对大连某水产养殖池塘,作者建立了一个基于Levenberg—Marquardt（LM）神经网络和遗传算法（GA）的溶解氧预测模型GA—LM,并将该模型与传统的BP神经网络进行比较分析。结果表明：使用本研究中建立的GA-LM模型预测的溶解氧值和实际测定值吻合较好,预测更为精准,运行时间明显减少。     

基于神经网络和遗传算法的池塘溶解氧预测模型

水产养殖池塘是一个多变量、非线性和大时延系统,其中溶解氧的预测也是一个复杂的问题。针对大连某水产养殖池塘,作者建立了一个基于Levenberg-Marquardt(LM)神经网络和遗传算法(GA)的溶解氧预测模型GA-LM,并将该模型与传统的BP神经网络进行比较分析。结果表明:使用本研究中建立的GA-LM模型预测的溶解氧值和实际测定值吻合较好,预测更为精准,运行时间明显减少。     

一种环保型血清分离胶用有机硅清洗剂的研制

将自制的非离子型FAE-48聚醚改性硅油与D-500聚醚改性硅油混合,并加入阴离子HPETS羧酸封端有机硅表面活性剂和助剂F68聚醚进行复配,制得用于清洗血清分离胶的一种新型清洗剂.通过单因素实验法与L9(34)正交实验法的优化,得到最佳原料配方:FAE-48聚醚改性硅油32.00 g,D-500聚醚改性硅油12.00 g,阴离子HPETS羧酸封端有机硅表面活性剂8.00 g,F68聚醚2.00 g.结果表明:该清洗剂对血清分离胶洗净率达到98.99%,碱性条件下稳定,不易燃.     

Generalized tube model of biased reptation for gel electrophoresis of DNA

A theoretical analysis of the reptational motion of DNA in a gel that includes the effects of molecular fluctuations has been used to explain the main features found in experiments involving periodic inversion of the electric field. The resonance-like decrease of the electrophoretic mobility as a function of pulse duration is related to transient "undershoots" in the orientation of the molecule, in agreement with recent experimental data. These features arise from a delicate interplay of internal and center of mass motion of the molecules under pulsed field conditions, and are important for the separation of DNA molecules in the size range 0.2 to 10 million base pairs.     

池塘分区集群式清洁养殖新模式的概念、原理与方法

对一种新的养殖模式——池塘分区集群式清洁养殖的概念、原理与方法进行了论述。池塘分区集群式清洁养殖(partition cluster clean aquaculture in ponds,PCCA)模式是一种不同于传统混养的池塘养殖新模式,即在健康养殖条件下将人工投喂的鱼类集群圈养于池塘小范围区域(即集群养殖区)中,通过控制鱼类粪便的排泄区域(沉淀排污区),做到及时将粪便清除到池塘外污水处理区,以降低鱼类粪便、残饵等对水体的污染及溶解氧消耗,使池塘中大部分水体区转变为水质净化区域,并通过该种养殖模式的实例,对其存在的问题和开发前景进行了讨论。研究表明,采用池塘内分区、养殖鱼类集群、精确投饵和及时清除粪便及残饵的池塘清洁养殖新模式,产量高于传统养殖模式,可达到节水减排的目的。     

土壤有机碳周转SCNC模型的研究与开发

本文介绍土壤有机碳周转SCNC模型的研究与开发。阐述了土壤有机碳周转的基本理论,模型设计与模型结构,介绍了模型的功能与特点。     

池塘分区集群式清洁养殖新模式的概念、原理与方法

对一种新的养殖模式———池塘分区集群式清洁养殖的概念、原理与方法进行了论述。池塘分区集群式清洁养殖( partition cluster clean aquaculture in ponds, PCCA)模式是一种不同于传统混养的池塘养殖新模式,即在健康养殖条件下将人工投喂的鱼类集群圈养于池塘小范围区域(即集群养殖区)中,通过控制鱼类粪便的排泄区域(沉淀排污区),做到及时将粪便清除到池塘外污水处理区,以降低鱼类粪便、残饵等对水体的污染及溶解氧消耗,使池塘中大部分水体区转变为水质净化区域,并通过该种养殖模式的实例,对其存在的问题和开发前景进行了讨论。研究表明,采用池塘内分区、养殖鱼类集群、精确投饵和及时清除粪便及残饵的池塘清洁养殖新模式,产量高于传统养殖模式,可达到节水减排的目的。     

径流含沙量测定方法研究

目的径流含沙量是水文测验和水土流失监测中必须测定的重要参数,更是衡量水土流失程度的重要指标,简单便捷的径流含沙量测定方法是目前水土保持监测中需要解决的关键问题之一,这对于实现水土流失量的自动监测和预警,及时准确地把握水土流失强度,进而选择合理的水土保持措施,开展水土流失治理均具有重要意义。方法本文通过采集国内不同省份的土壤样品,利用室内实验,构建了称重法测定径流含沙量的基本原理,提出了计算含沙量的经验模型,探讨了称重法测定径流含沙量精度的主要因素（泥沙比重、泥水样体积、水温）。结果称重法测量径流含沙量的模型精度较高,能满足水土保持监测中径流含沙量测定的精度要求,径流含沙量在5.00 ~ 20.00 g/L时,平均相对误差 < 20.00%;径流含沙量在20.00 ~ 200.00 g/L时,平均相对误差 < 5.00%。泥沙比重对泥沙含量测定结果的影响不显著,可采用水土流失地区表层土壤平均比重（变化范围基本在2.50 ~ 2.70之间）,利用称重法模型计算出径流含沙量。泥水样体积的测定误差是影响称重法测量泥沙含量精度的关键,研制以称重法为基本原理的径流泥沙含量自动监测仪器时,准确测量泥水样的体积最为关键。温度对称重法测量径流含沙量的精度影响很小（P > 0.05）。结论称重法操作简单,精度高,在水土流失自动监测领域具有良好的应用前景。      

A model for a seismic computerized alert network

In large earthquakes, damaging ground motions may occur at large epicentral distances. Because of the relatively slow speed of seismic waves, it is possible to construct a system to provide short-term warning (as much as several tens of seconds) of imminent strong ground motions from major earthquakes. Automated safety responses could be triggered by users after receiving estimates of the arrival time and strength of shaking expected at an individual site. Although warning times are likely to be short for areas greatly damaged by relatively numerous earthquakes of moderate size, large areas that experience very strong shaking during great earthquakes would receive longer warning times.     

西藏达则错盐湖沉积背景与有机沉积结构

以西藏拟溞(Daphniopsis tibetana Sars)为优势浮游动物物种的低盐度盐湖是西藏湖泊的一个重要类型,以达则错为代表,分析了其沉积背景及沉积物组成。结果如下:(1)湖泊敞水区无机沉积以内生化学沉积为主,可代表深水盐湖无机沉积物的自然沉积过程。(2)达则错盐湖浮游植物以蓝藻、硅藻、裸藻、绿藻为主,总生物量11.35 mg/L;浮游动物生物量为4.92 mg/L,其中西藏拟溞占 82.30%;浮游植物残体受盐梯度影响在盐梯度层之上聚集,而浮游动物残体及粪粒(Fecal pellets)因外表有碳酸盐附着可穿过盐梯度层沉积湖底,生物残体与浮游动物代谢产物构成了沉积有机物的物质基础。(3)表层沉积物平均含水量为66.70%,粒径0.004-0.02 mm范围内的颗粒物含量最大,占20.42%,其次为<0.004 mm的粘土,占4.53%。(4)表层沉积物总有机碳(TOC)平均含量为27.99 mg/g(干重),其中颗粒有机碳(POC)约为18.11 mg/g,占TOC的64.70%;在POC中,西藏拟溞粪粒贡献最大,约占POC的60.48%,占TOC的39.06%,占沉积物总量的1.12%,其次为西藏拟溞残体,占POC的38.85%。分析结果表明盐湖因其独特的水化学和生物学特征具有较强的沉积能力,以化学沉积为主的无机沉积及以西藏拟溞粪粒和残肢碎屑为主的有机沉积构成了该类型盐湖颗粒物沉降及沉积的主要过程。     

Physical model for the decay and preservation of marine organic carbon

Degradation of marine organic carbon provides a major source of atmospheric carbon dioxide, whereas preservation in sediments results in accumulation of oxygen. These processes involve the slow decay of chemically recalcitrant compounds and physical protection. To assess the importance of physical protection, we constructed a reaction-diffusion model in which organic matter differs only in its accessibility to microbial degradation but not its intrinsic reactivity. The model predicts that organic matter decays logarithmically with time t and that decay rates decrease approximately as 0.2 x t(-1) until burial. Analyses of sediment-core data are consistent with these predictions.     

Ages estimated from a diffusion equation model for scarp degradation

The diffusion equation derived from the continuity equation for hillslopes is applied to scarp erosion in unconsolidated materials. Solutions to this equation allow direct calculation of the product of the rate coefficient and the age of the scarp from measurements of scarp morphology. Where the rate coefficient can be estimated or can be derived from scarps of known age, this method allows direct calculation of unknown ages of scarps.     

有机肥氮素释放动态模型的初步研究

在大田填埋试验资料的基础上,假定有机肥C／N随分解时间而变,其变化规律遵循一阶动力学方程,根据作物残体分解过程中C／N的变化及业已建成的作物残体有机碳分解动态模型,建立了有机肥氮素释放动态模型。分析结果表明,模型对于有机物料初始C／N和木质素含量有较强的敏感性。利用文献资料对所建模型进行了验证,结果表明,模型对大部分数据有较好的模拟效果。本模型可以为指导有机肥的合理施用提供依据。     

基于有机元素含量的猪粪热值预测模型

探讨利用猪粪有机元素含量预测猪粪热值的可行性,建立基于C、H、N、S、O等5种有机元素含量的高、低位热值预测模型.采集了160个猪粪样品,利用EA3000型元素分析仪和IKA-C2000型氧弹量热仪分别测定其C、H、N、S、O元素的含量和高、低位热值.相关分析表明,C、H、N这3种元素的含量与热值之间存在极显著相关,而S、O这2种元素含量与热值之间的相关不显著;利用120个猪粪样品的测定结果,采用多元线性回归分析建立的基于C、H、N含量的热值预测模型可以较准确地利用碳、氢、氮预测猪粪热值,高位热值和低位热值预测模型的决定系数R2分别为0.836和0.785.用40个样品对热值模型进行外部验证,高位热值和低位热值均方根误差RMSE分别为621.31、620.85 J/g,相对均方根误差RRMSE分别为3.74％和4.06％.结果表明,多元线性回归法建立的基于有机元素含量的猪粪热值预测模型的预测结果较准确,利用猪粪的元素含量预测其热值是可行的.     

Estimating soil organic carbon from soil reflectance: a review

Soil organic carbon (SOC) concentration is a useful soil property with which to guide agricultural applications of chemical inputs. To enable this, simple, accurate, rapid and inexpensive methods are needed to produce maps of surface SOC concentrations. Researchers have investigated estimates of soil surface properties from remotely sensed information as a means of rapidly quantifying and monitoring some surface soil properties, such as SOC. The objective of this paper is to review the potential and limitations of remotely sensed data for mapping and evaluating SOC. Several statistical methods including simple regression models, the ‘soil line’ approach, principal component analysis and geostatistics have been applied to data to investigate the accuracy of such estimates. A review of the literature shows that predictive equations are not universal and require new regression models for every scene. An important benefit of remotely sensed data is to suggest a sampling strategy that can lead to improved representation of spatial heterogeneity in SOC.