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1.
该文利用电化学方法制备了聚吡咯掺杂磷钼杂多酸(PPy/PMo12)膜修饰电极,该修饰电极对溶液中的BrO3-有很好的电流响应.纳米TiO2-KBrO3共存体系可以光催化氧化水体中的有机物,体系中的BrO3-浓度变化可用制备的修饰电极进行测定,继而建立了一种利用PPy/PMo12膜修饰电极测定水体中化学需氧量(COD)的新方法.实验中以葡萄糖为标准物质,研究了测定机理,优化了测定条件.实验结果表明,该方法操作条件温和,能实现快速、准确的测定.COD值在50.0~500.0 mg·L-1浓度范围内,与修饰电极上的电流响应信号值成线性关系,检测限为25.0 mg·L-1.将该方法用于实际水样的检测,测定结果与COD标准分析法有好的一致性.  相似文献   

2.
复杂气相化学反应动力学的数值模拟   总被引:2,自引:1,他引:1  
用VBA与Matlab编写程序,数值模拟了复杂气相化学反应动力学过程.该程序不但能实时显示输出结果,还有灵敏度分析、估计误差传递等功能.用该程序计算了海洋大气边界HO2自由基的浓度及日变化曲线.计算得到的HO2自由基的浓度水平及日变化规律在方法误差范围内与实验测定结果基本一致.  相似文献   

3.
建立了1种基于独立成分分析的多元校正方法,结合近红外光谱分析技术进行多组分同时测定.以甲苯、氯苯和正庚烷构成的混合体系为例进行建模和预测,并将预测结果与主成分回归所得的结果进行了比较.结果主成分回归方法对独立测试集32例样本中甲苯、氯苯和正庚烷浓度的预测平均相对误差分别为4.5030、6.0231及9.6042,而独立成分回归方法对三组分浓度的预测平均相对误差分别为4.3871、4.1465及5.8104,说明本方法具有很强的预测能力,可作为1种实用的多元校正方法.  相似文献   

4.
测定合成氨生产过程中的工艺冷凝液的回收利用是一项很重要的节能措施。但是合成氨系统的冷凝液往往由于管壁渗漏,使少量氨以游离状或铵盐形式存在于冷凝液中。而为了确保合成氨系统工艺冷凝液回收装置回收的工艺冷凝液不影响后续工序的正常运行,工艺冷凝液中氨等杂质的含量必须控制在一定的范围内,因此精确测定冷凝液中氨含量是回收利用冷凝液的先决条件。测定工艺冷凝液中氨离子用选择电极等测定法,该方法在工艺中受温度、压力和膜头密封等因素的影响使其不能正常与运行、且仪器价格昂贵。我公司采用电导率和氨根离子之间的浓度关系诺模图快速准确地反映合成氨冷凝液浓度值,满足合成氨冷凝液回收装置的运行要求。  相似文献   

5.
该文以本体聚合、沉淀聚合、悬浮聚合三种聚合方法分别成功地研制了以甲基丙烯酸为功能单体,对氯苯氧乙酸为印迹分子的印迹聚合物.通过测定印迹聚合物对不同浓度的对氯苯氧乙酸的吸附量以及对相同浓度的苯氧乙酸、对氯苯氧乙酸和2,4-二氯苯氧乙酸的吸附量来研究印迹聚合物的等温吸附性能和选择性能.与此同时,研制空白聚合物进行对照实验.实验结果表明,印迹聚合物具有较好的吸附能力和选择性能.另外,本体聚合方法研制的聚合物性能优于沉淀聚合和悬浮聚合.  相似文献   

6.
二元混合蒸汽的气相浓度与液相浓度和压力有关.通常二元混合蒸汽的浓度可用滴定的实验方法确定,但当压力在负压时,滴定法难于应用.本文使用计算法,利用UNIFAC基团贡献法计算模型,使用VB语言编制了在低压(0~101325)Pa下,乙醇水溶液相平衡计算程序.通过与文献的比较,气相浓度和露点温度的最大的相对误差为9.1%和3...  相似文献   

7.
该文利用光催化氧化技术建立了一种测定地表水等低污染水体COD值的新方法.纳米ZnO/TiO2复合膜与单纯的纳米TiO2膜相比,提高了系统的电荷分离效率,扩展了其光谱响应范围,从而表现出更好的光催化效率.纳米ZnO/TiO2复合膜-Mn(Ⅶ)共存体系光催化降解水体中的有机物,COD值在0.3~10.0mg/L浓度范围内与信号成线性关系,检测限为0.1 mg/L.将该方法用于实际水样的检测,测定结果与COD标准分析法有较好的一致性.  相似文献   

8.
提出了用氟电极测定水中铝的两种方法,在F^-浓度固定的情况下,利用ΔE~CAl^3+的线性关系,实测了饮用水样,与国标法相比,结果满意。  相似文献   

9.
MDI反应液中含有大量溶剂氯苯,需要进行浓缩,获得较纯的粗MDI。采用多个塔顺序提高MDI浓度,每个塔的分离纯度不同,其蒸发量与蒸发温度不同,采用模拟退火算法优化各个塔底出料浓度、操作压力和设备尺寸,同时考虑各个塔间的热集成,得到年度费用最低的工艺流程。  相似文献   

10.
芳香胺离子是芳香胺致癌进程中产生的中间体,它与嘌呤核酸反应,生成芳香胺-DNA加成物,从而导致癌症的发生。在之前的理论研究中,我们发现,N7质子化的嘌呤与芳香胺离子反应时,过渡态的气相和液相中激发能差别很大,其具体原因还不清楚。因此,本文中,应用ABEEM/MM-MD分子动力学模拟方法,研究了溶剂对这类反应的影响。在具体的溶剂模拟中,我们使用显含的水分子作为溶剂,模拟得到了整个反应过程中N7质子化嘌呤与芳香胺离子的水的径向分布函数。分析这些结果可以发现,当反应进行到有过渡态出现时,水溶剂与过渡态的相互作用会变的比反应初始阶段强得多。从这个结果,可以得到过渡态的激发能在气相和液相中差别很大的原因是,在液相反应中,水溶剂与过渡态比较强的相互作用降低了过渡态的激发能。此外,我们也使用ABEEM方法得到了所研究反应过程中的电荷变化情况。  相似文献   

11.
Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.  相似文献   

12.
European Community policy and the market   总被引:1,自引:0,他引:1  
Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.  相似文献   

13.
融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。  相似文献   

14.
Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.  相似文献   

15.
This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.  相似文献   

16.
Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008  相似文献   

17.
为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.  相似文献   

18.
Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.  相似文献   

19.
This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)SM and Team Software Process (TSP){SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.  相似文献   

20.
基于复小波噪声方差显著修正的SAR图像去噪   总被引:4,自引:1,他引:3  
提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。  相似文献   

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