山西石灰性土壤速效磷、钾测定方法的比较

用M ehlich3通用浸提剂法对山西石灰性土壤速效磷、钾的含量进行了测定,并与常规方法进行比较。结果表明:M ehlich3法与常规土壤速效磷、钾测定方法的测定结果呈显著正相关性。磷的替代性较差,钾的替代性较好,且两元素之间可以相互换算。     

不同土壤类型Mehlich3方法与常规方法测定土壤养分相关性研究

采取Mehlich3(以下简称M3)方法和常规标准方法测定了土壤有机质、有效磷和速效钾,分析了两种测定结果的相关性,得出水稻士有效磷相关系数为0.8529,速效钾相关系数为0.8655.草甸土土壤有机质Mehlich3方法与常规方法相关系数达到为0.9659,有效钾Mehlich3方法与常规方法相关系数达到0.9606.M3方法与常规方法测定土壤养分有一定的相关性,其数值可以相互转换利用.     

Mehlich3方法与常规方法测定土壤养分相关性初步研究

采取Mehlich3(以下简称M3法)方法和常规标准方法测定了41个土壤样品的有效磷、速效钾、交换性钙、交换性镁、有效铁、有效锰、有效铜、有效锌和有效硼.通过对两种方法测定结果的分析,探讨二者的相关性.土壤有效磷M3方法与常规方法相关系数达到0.9085,为最高,有效铜M3方法与常规方法相关系数为0.1556,为最低.有效铜、有效硼测定结果的相关性很差.M3方法与常规方法测定土壤养分在有效磷、速效钾、交换性钙、交换性镁、有效铁、有效锰、有效锌上达到极显著水平,其数值可以通过回归方程相互转换利用.     

稀盐溶性磷表征石灰性土壤供磷能力的研究

稀盐 ( 0 .0 1mol/LCaCl2 )提取的磷与冬小麦相对吸磷量的线性相关系数r为 0 734 ,达 0 0 1 %显著水平 .与其他化学方法 (如Olsen、Machigin、Al-Abbas、MehlichⅢ、Mesheryakov)和电超滤法 (EUF)的相关性也达 0 1 %显著水平 .该法操作简便、快速、经济 ,还可以在同一提取液中同时测定氮、磷、钾及其它营养元素 ,是测定石灰性土壤有效磷的可靠方法     

国产和进口阴离子交换树脂膜埋置法测定土壤中的微量元素

对采自全国各地20个土壤样品进行测定.结果表明,树脂膜法测定的土壤微量元素值与DT-PA法测定的土壤有效微量元素之间具有极显著的相关性,国产树脂膜的测定值与DTPA法测定值间的相关性稍优于进口树脂膜.阴离子交换树脂膜法测定的土壤有效Mn与植物实际吸Mn量间的相关性好于DTPA法测定值与植物实际吸Mn量间的相关性,国产树脂膜法测定值与植物实际吸Mn量间的相关性稍好于进口树脂膜,指数相关性好于一次直线相关性.离子交换树脂膜法可以用来测定原位土壤中的有效微量元素,国产树脂膜可以替代进口树脂膜.     

土壤养分有效性测定及其方法

在提出土壤养分有效性测定概念的基础上 ,本文对各种土壤养分有效性的测定方法进行了总结 ,讨论了这些方法的测定机理、测定效果及近几年的进展。这些方法包括用于磷钾等元素测定的树脂法、用于氮测定的生物培养法和化学提取法、磷测定的氧化铁试纸法和氢氧化铁透析管法和钾的四苯硼钠法     

基于Altera ASI IP核的ASI发送卡实现

本文提出了一种基于Altera公司的ASI IP核来代替Cypress公司的CY7B923实现ASI信号的发送,详细阐述了ASI IP核的实现.使用FPGA编程实现ASI接口转换与发送功能,具有更大的灵活性,且接口复合DVB-ASI接口规范.文中介绍了ASI的特点与构成,并详细阐述了使用FPGA实现ASI高速接口的硬件实现方法,最后给出了相应的测试实验.接口符合ASI接口规范,实现了高达270Mbit/s的数据传输.     

探地雷达测定土壤含水率研究综述

准确快速测定土壤含水率,在理论研究与实际应用中都具有重要意义.在综合分析烘干法、中子法、时域反射法和遥感4种土壤含水率测定方法的优缺点基础上,指出探地雷达是一种适合于中尺度的土壤含水率测定的技术.对探地雷达以及探地雷达测定土壤含水率的技术原理与方法进行全面介绍,并以介电常数与土壤含水率的关系模型为主,对国内外这方面的研究工作以及存在的问题进行了总结.最后指出,探地雷达测定土壤含水率是一项非常有前景的技术,但目前国内在这方面的研究工作与国外相比远远不够,今后应加强这方面的研究工作.     

土壤中硒和硫相互作用的研究

综述了硒和硫的地球化学特征,土壤中硒和硫含量、形态的相互关系和吸附、解吸中的相互作用及生物化学过程的差异性.硒和硫在内生作用中的地球化学行为极为相似,而在表生作用下两者的地球化学行为明显分离.土壤中硒和硫的形态类似,其含量有明显的相关性,土壤对硒和硫的吸附也具有相似性.土壤中硒和硫相互作用的特点与土壤类型、硒和硫的浓度有关,土壤中硒和硫竞争的机制有待于深入的研究.     

库仑法和标准重铬酸钾法测定废水中化学雷氧量的相关性比较研究

本文通过实验方法对库仑法和标准重铬酸钾法测定废水中的化学需氧量的相关性进行了比较研究。实验结果表明两种方法存在相关性差异，在实际测定过程可用校正系数法对库仑法测定结果进行修正。     

结构应变的无线监测及融合技术

针对结构应变监测,设计了一类无线应变传感装置,并对该装置采集的数据进行了数据融合处理.,介绍了无线应变传感器的硬件集成;描述了基于算术平均值的无线应变传感器信息融合方法;结合应变的无线测试实验,应用数据融合技术对测量数据加以分析处理.研究表明:所集成的无线应变传感器,安装简单、携带方便;采用了数据融合处理的应变信号更加准确;基于数据融合的无线应变传感器适合在现场测试中应用.     

Coding, analysis, interpretation, and recognition of facialexpressions

We describe a computer vision system for observing facial motion by using an optimal estimation optical flow method coupled with geometric, physical and motion-based dynamic models describing the facial structure. Our method produces a reliable parametric representation of the face's independent muscle action groups, as well as an accurate estimate of facial motion. Previous efforts at analysis of facial expression have been based on the facial action coding system (FACS), a representation developed in order to allow human psychologists to code expression from static pictures. To avoid use of this heuristic coding scheme, we have used our computer vision system to probabilistically characterize facial motion and muscle activation in an experimental population, thus deriving a new, more accurate, representation of human facial expressions that we call FACS+. Finally, we show how this method can be used for coding, analysis, interpretation, and recognition of facial expressions     

The who, what, why, where, and when of IT outsourcing

Outsourcing of IT functions has become so pervasive that IT managers and CIOs cannot ignore it. To complicate the matter, outsourcing to other countries has become increasingly popular. The advantages of this type of outsourcing include cost savings, 24/7 operation, and access to highly specialized skills. Yet a strategic alliance with a geographically and culturally remote partner presents its own unique challenges. Thus, IT professionals should not take the strategic questions of whether or not to outsource lightly, or avoid it. Rather, they can make such a decision by analyzing the responses to the following five key questions, what we call the five Ws: Who should outsource? What is outsourcing? Why outsource? Where should you outsource? When should you outsource? This article emerged from a focus group of CIOs conducted by the CIO Institute, a not-for-profit community of practice for CIOs in the Greater Philadelphia region.     

Enthalpies of formation of binary phases in the systems FeTi,FeZr, CoTi,CoZr, NiTi,and NiZr,by direct reaction calorimetry

The enthalpies of formation of the binary compounds in the systems AB where A is taken in the group VIII and B in the group IV A are measured by direct reaction calorimetry at high temperatures. Checks are made to ensure that the stoichiometry and the structure of each phase is obtained.     

Development of a three-dimensional,regional, coupled wave,current, and sediment-transport model

We are developing a three-dimensional numerical model that implements algorithms for sediment transport and evolution of bottom morphology in the coastal-circulation model Regional Ocean Modeling System (ROMS v3.0), and provides a two-way link between ROMS and the wave model Simulating Waves in the Nearshore (SWAN) via the Model-Coupling Toolkit. The coupled model is applicable for fluvial, estuarine, shelf, and nearshore (surfzone) environments. Three-dimensional radiation-stress terms have been included in the momentum equations, along with effects of a surface wave roller model. The sediment-transport algorithms are implemented for an unlimited number of user-defined non-cohesive sediment classes. Each class has attributes of grain diameter, density, settling velocity, critical stress threshold for erosion, and erodibility constant. Suspended-sediment transport in the water column is computed with the same advection–diffusion algorithm used for all passive tracers and an additional algorithm for vertical settling that is not limited by the CFL criterion. Erosion and deposition are based on flux formulations. A multi-level bed framework tracks the distribution of every size class in each layer and stores bulk properties including layer thickness, porosity, and mass, allowing computation of bed morphology and stratigraphy. Also tracked are bed-surface properties including active-layer thickness, ripple geometry, and bed roughness. Bedload transport is calculated for mobile sediment classes in the top layer. Bottom-boundary layer submodels parameterize wave–current interactions that enhance bottom stresses and thereby facilitate sediment transport and increase bottom drag, creating a feedback to the circulation. The model is demonstrated in a series of simple test cases and a realistic application in Massachusetts Bay.     

Coupled Transformation of Schemas, Documents, Queries, and Constraints

Coupled transformation occurs when multiple software artifacts must be transformed in such a way that they remain consistent with each other. For instance, when a database schema is adapted in the context of system maintenance, the persistent data residing in the system's database needs to be migrated to conform to the adapted schema. Also, queries embedded in the application code and any declared referential constraints must be adapted to take the schema changes into account. As another example, in XML-to-relational data mapping, a hierarchical XML Schema is mapped to a relational SQL schema with appropriate referential constraints, and the XML documents and queries are converted into relational data and relational queries. The 2LT project is aimed at providing a formal basis for coupled transformation. This formal basis is found in data refinement theory, point-free program calculation, and strategic term rewriting. We formalize the coupled transformation of a data type by an algebra of information-preserving data refinement steps, each witnessed by appropriate data conversion functions. Refinement steps are modeled by so-called two-level rewrite rules on type expressions that synthesize conversion functions between redex and reduct while rewriting. Strategy combinators are used to composed two-level rewrite rules into complete rewrite systems. Point-free program calculation is applied to optimized synthesize conversion function, to migrate queries, and to normalize data type constraints. In this paper, we provide an overview of the challenges met by the 2LT project and we give a sketch of the solutions offered.     

Quiescence, Fairness, Testing, and the Notion of Implementation

Two formalisms for concurrency, the Input/Output automaton model and the theory of testing, are compared and are shown to have common foundations. The relationship between the fair and quiescent preorders of I/O automata is investigated and the two preorders are shown to coincide subject to some restrictions. I/O automata are encoded into the theory of testing and the reversed preorder is shown to be equivalent to the quiescent preorder for strongly convergent, finitely branching I/O automata up to encoding. Conversely, a theory of testing is defined directly on I/O automata, and the new reversed preorder is shown to coincide with the quiescent preorder on strongly convergent, finitely branching I/O automata.