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1.
采用等温溶解法研究了三元体系Mg2+//C1-,borate-H20在308.15 K时的稳定相平衡;测定了上述体系液相中各组份的平衡溶解度及物化性质(密度和pH),根据实验数据绘制了相应相图和物化性质组成图.该体系在308.15 K时有1个共饱点(水氯镁石+镁硼酸盐)、2条饱和溶解度曲线和2个结晶相区,无复盐及固溶体产生.溶液的物化性质随着MgC12浓度的增大而有规律地变化.体系中章氏硼镁石发生转化,MgC12浓度不同,转化最终产物不同.最后,初步探讨了章氏硼镁石的转化机理.  相似文献   

2.
采用等温溶解法研究了三元体系Mg2+//C1-,borate-H20在308.15 K时的稳定相平衡;测定了上述体系液相中各组份的平衡溶解度及物化性质(密度和pH),根据实验数据绘制了相应相图和物化性质组成图.该体系在308.15 K时有1个共饱点(水氯镁石+镁硼酸盐)、2条饱和溶解度曲线和2个结晶相区,无复盐及固溶体...  相似文献   

3.
东台吉乃尔盐湖夏季卤水25℃等温蒸发实验研究   总被引:1,自引:0,他引:1  
针对东台吉乃尔盐湖夏季卤水进行25℃等温蒸发实验研究,揭示卤水蒸发结晶路线和析盐规律。实验结果表明:夏季盐湖卤水蒸发析盐过程依次为石盐、石膏、软钾镁矾、泻利盐、钾石盐、六水泻盐、钾盐镁矾、光卤石、一水硫酸锂和水氯镁石,并将分阶段析盐序列绘制在相应的介稳相图上,结晶路线与介稳相图基本吻合。  相似文献   

4.
三方硼镁石合成方法研究   总被引:1,自引:0,他引:1  
采用液-固转化法,研究了室温下水溶液中三方硼镁石的合成方法,并初步探讨了三方硼镁石的结晶机理.合成的三方硼镁石晶体,经化学分析法、X-ray粉晶衍射法、红外光谱法和热分析方法物相鉴定,发现合成晶体纯度高,可满足应用于该矿物的溶液化学性质研究.  相似文献   

5.
水滑石晶体生长机理   总被引:1,自引:0,他引:1  
从“生长基元”角度出发,研究了水滑石晶体生长机理,结果表明水滑石生长形态符合负离子配位多面体生长模型.采用Raman光谱分析了镁铝水滑石、铜镁铝类水滑石、铜锌镁铝类水滑石生长溶液拉曼位移,发现镁铝水滑石层板生长基元是[Mg-(0H)6]^4-,[Al-(0H)6]^3-;含铜锌类水滑石的生长基元是[Mg-(0H)6]^4-(M=Zn^2+,Cu^2-),[Mg-(0H)6]^4-,[A1-(0H)6]^3-,水滑石的生长是生长基元先叠合为金属板层,然后再吸附阴离子A”及H:0,依此循环而组成层状化合物.水滑石生长基元所处生长环境不同,会使生长形态不同,以至形成不同外形的水滑石.文章还分析了为什么含铜类水滑石较难合成的原因.  相似文献   

6.
相平衡与相图是盐湖卤水资源开发利用的理论依据,本文重点归纳总结了含硼资源开发的有关相化学研究进展.内容主要包括硼酸和硼酸盐体系的稳定相平衡、硼酸盐体系的介稳相平衡及含硼水盐体系溶解度理论计算的研究现状,重点总结了我国卤水中硼资源和硼矿资源开发利用的有关相平衡研究现状,指出了存在的主要问题和发展方向.  相似文献   

7.
利用糠醛废水中醋酸含量较高的特点,设计了能够在处理糠醛废水的同时回收利用醋酸,生产环保型融雪剂醋酸钙镁(CMA)的工艺条件。并利用该工艺建立了日产5吨CMA的生产线,对所生产的CMA产品的品质和性能进行了评价。研究结果表明:所设计的工艺路线可以用于实际生产,能够回收利用糠醛废水中的水和醋酸,基本实现零排放。所生产的CMA有效成分含量较高,环境影响很小,融雪能力较好,可用于冬季路面的融雪。  相似文献   

8.
盐湖卤水资源的成功开发,需以相应的相平衡与相图研究成果为指导,开展含钙多组分卤水体系相平衡的研究,对于我国近年发现的含钙卤水资源的开发利用具有重要的意义。本文主要从含钙的海水体系、碳酸盐体系、硼酸盐体系和锂钙共存的卤水体系等方面,归纳总结了国内外关于含钙卤水体系的相平衡研究进展,探讨了研究中存在的一些问题,进一步指出了含钙卤水体系相平衡的研究方向。  相似文献   

9.
2-氯丙酸是合成农药、染料和农林化学品的重要原料。本文缘述了国内外2-氯丙酸的合成方法及各种方法的工艺条件,分析了各种方法的优缺点,并展望了2-氯丙酸合成路线的发展趋势。  相似文献   

10.
基于人水系统概念和嵌入式系统动力学(ESD)方法,以一个相对独立的城市区为例,介绍人水系统模拟的ESD模型,说明ESD模型的优越性。通过ESD模型的模拟计算,分析实例区人水系统演变的主要影响因素以及调控方向和措施。模拟结果表明,该城市区总用水量在各年远未达到水资源可利用量,而水质控制目标已经达到临界状态;其发展的瓶颈是污水处理能力偏低,可以通过建设污水处理厂,增加污水处理能力,以提高该区的发展规模。  相似文献   

11.
Summary Five topics concerning medical population genetics have been selected for discussion: in the field of population cytogenetics, the frequency of chromosomal aberrations and the roles of mutation and selection in the maintenance of balanced rearrangements are studied; the long term genetic effects of treatment and prevention of genetic diseases are reviewed; the relationships between malaria and the sickle-cell trait are discussed; some recent works concerning human DNA polymorphisms in the field of population, genetics are presented, and finally, some methods of genetic epidemiology are described.  相似文献   

12.
首先介绍了农田渍害的表现特征;其次根据监测原理,将国内外农田溃害遥感监测的主要方法分为地表指示标志法、地下水位反演法和与非遥感方法相结合的综合分析法,并分别对各类方法的原理、技术、适用范围及优缺点进行分析,发现各种方法均能解决特定的农田渍害监测问题,同时也存在着缺陷和局限性;最后,进行了总结并指出了两种潜在的遥感监测方...  相似文献   

13.
FBP和FCNN网络是模式识别中应用最为广泛的两种神经网络,本文将这两种网络应用于车型识别,分别建立了车型识别模型。利用混沌对初值的极端敏感依赖提出了FCNN网络算法,通过对车型图像数据库进行仿真实验,对比分析它们各自的识别率和泛化能力等性能指标,证明了FCNN网络算法的有效性。  相似文献   

14.
This paper is concerned primarily with the evaluation and comparison of objective and subjective weather forecasts. Operational forecasts of three weather elements are considered: (1) probability forecasts of precipitation occurrence, (2) categorical (i.e. non-probabilistic) forecasts of maximum and minimum temperatures and (3) categorical forecasts of cloud amount. The objective forecasts are prepared by numerical-statistical procedures, whereas the subjective forecasts are based on the judgements of individual forecasters. In formulating the latter, the forecasters consult information from a variety of sources, including the objective forecasts themselves. The precipitation probability forecasts are found to be both reliable and skilful, and evaluation of the temperature/cloud amount forecasts reveals that they are quite accurate/skilful. Comparison of the objective and subjective forecasts of precipitation occurrence indicates that the latter are generally more skilful than the former for shorter lead times (e.g. 12–24 hours), whereas the two types of forecasts are of approximately equal skill for longer lead times (e.g. 36–48 hours). Similar results are obtained for the maximum and minimum temperature forecasts. Objective cloud amount forecasts are more skilful than subjective cloud amount forecasts for all lead times. Examination of trends in performance over the last decade reveals that both types of forecasts for all three elements increased in skill (or accuracy) over the period, with improvements in objective forecasts equalling or exceeding improvements in subjective forecasts. The role and impact of the objective forecasts in the subjective weather forecasting process are discussed in some detail. The need to conduct controlled experiments and other studies of this process, with particular reference to the assimilation of information from different sources, is emphasized. Important characteristics of the forecasting system in meteorology are identified, and they are used to describe similarities and differences between weather forecasting and forecasting in other fields. Acquisition of some of these characteristics may be beneficial to other forecasting systems.  相似文献   

15.
Summary Temporal and regional variations in psychological processes have been associated with three geological factors. They are geochemical profiles, geomagnetic variations, and tectonic stresses. In the geochemical domain, copper, aluminum, zinc, and lithium may influence the incidence of thought disorders such as schizophrenia and senile dementia. These common elements are found in many soils and ground water. Geomagnetic variations have been correlated with enhanced anxiety, sleep disturbances, altered moods, and greater incidences of psychiatric admissions. The effects are usually brief but pervasive. Transient and very local epidemics of bizarre and unusual behaviors are sociological phenomena that sometimes precede increases in earthquake activity within a region; they have been hypothesized to be associated with tectonic strain. Many of the contemporary correlations between geological factors and human behavior are also apparent within historical data. The effects of geophysical and geochemical factors upon human behavior are not artifactual, but they are complex and often not detected by the limited scope of most studies.  相似文献   

16.
17.
Macroeconomic indicators are typically appraised in seasonally adjusted form, and forecasts are often presented in a similar way (as annual changes, for example). Moreover, the quarterly macroeconomic models used in forecasting are commonly estimated from seasonally adjusted data. Nevertheless, these models can generate forecasts with seasonal patterns, and this paper assesses the cause and cure of this phenomenon. It is found that forecast seasonality is induced by seasonality in the various inputs: exogenous variables, residual adjustments, the dynamic specification of certain equations, and annual changes in policy variables. Series changing annually but observed quarterly are termed ‘intercalated series’, and are simple examples of periodic processes. Forecast seasonality can be removed by appropriate adjustment of all these inputs. Models containing explicit future expectations variables solved in a model-consistent manner are also considered: numerical sensitivity to the terminal quarter may result from terminal conditions that require adjustment when seasonality is present.  相似文献   

18.
美国再制造业与我国的研究评述   总被引:1,自引:0,他引:1  
基于再制造、传统生产运行管理内涵及实践感受,提出再制造生产模式概念,并归纳其七项特征,以此评述全文。将美国的研究发展过程划分两阶段,归纳了第一阶段对我国有借鉴作用的七条经验;阐述了第二阶段的研究内容和特点,并分析了两阶段的形成机理和可能的发展趋势。总结出我国研究的形成过程和特点,通过与美国对比,指出了两个层面的差距,并提出中国特色和跨越式发展的论点,由此分析了发展的可能性及当前和未来应研究的方向、内容和方式。  相似文献   

19.
20.
Hydroxyproline-rich glycoproteins (HRGPs) are ubiquitous architectural components of the growing plant cell wall, accounting for as much as 10-20% of the dry weight. HRGPs are implicated in all aspects of plant growth and development, including responses to stress. The HRGP superfamily contains three major groups which represent a continuum of peptide periodicity and hydroxyproline-O-glycosylation. These groups range from the highly periodic and lightly arabinosylated repetitive proline-rich proteins (PRPs), through the crosslinked extensins which are periodic and highly arabinosylated, to the arabinogalactan-proteins (AGPs) which are the most highly glycosylated and least periodic. The repetitive units are small, often only four- to six-residue-glycosylated modules viewed hypothetically as functional motifs, or glycomodules. The Hyp contiguity hypothesis predicts that Hyp arabinosylation increases with Hyp contiguity and that clustered noncontiguous Hyp residues are sites of arabinogalactan polysaccharide addition in the AGPs and gums. Recent results involving glycosylation site mapping of endogenous HRGPs and HRGP design using synthetic genes have corroborated the hypothesis. The uses of synthetic genes in HRGP glycosylation site mapping and structural/functional analysis are also discussed.  相似文献   

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