青海湖盐水氯镁石(MgCl_2·6H_2O)的热分析研究

本文用热分析方法,对青海湖盐下氯镁石(MgCl_2·6H_2O)的热分解反应进行了TG、DTG、DTA、DSC的测定,配合分解气的化学分析、气相色谱分析和固体物的红外光谱分析,解释了DTA曲线,初步推断了MgCl_2·6H_2O热分解的机理。 MgCl_2·6H_2O 118℃—→熔融 MgCl_2·6H_2O 156℃—→MgCl_2·4H_2O 2H_2O MgCl_2·4H_2O 191℃—→MgCl_2·2H_2O 2H_2O MgCl_2·2H_2O 200℃—→MgCl_2·H_2O H_2O MgCl_2·H_2O 251℃—→MgOHCl HCl MgOHCl 461℃—→MgO HCl总失重率为78.5％。用Kissinger法测得MgCl_2·6H_2O→MgCl_2·4H_2O 2H_2O的表观活化能为30.4KCal/mol。MgOHCl→MgO HCl表观活化能为49.7KCal/mol。测定热分解反应的热效应为97.2KCal/mol。     

发孔腐蚀工艺对电容器阳极铝箔比容的影响

用H2SO4-HCl腐蚀体系对高纯铝箔在不同条件下进行发孔腐蚀实验,在85℃扩孔腐蚀液中以0.15 A/cm2的直流电流扩孔腐蚀600 s,经化成处理后采用静电容量测试仪测量腐蚀箔的比容.研究了HCl浓度、电流密度、时间和温度对腐蚀箔比容的影响规律,利用SEM分析了腐蚀孔的形态变化.结果表明,随着c(HCl)的增加,比容呈先增大后减小的规律,当c(HCl)=2.0mol/L时,比容达到最大值;电流密度、时间、温度对比容的影响也有与c(HCl)类似的规律,比容达到最大值所对应的电流密度、温度和时间分别为0.6 A/cm2,80℃和140 s.当c(HCl)为3 mol/L,电流密度为0.7 A/cm2时,腐蚀箔出现明显"并孔"现象.     

FFA对巨噬细胞UCP2蛋白的影响

为检测游离脂肪酸对巨噬细胞解耦连蛋白2的影响,探讨肥胖与巨噬细胞解耦连的关系。采用培养RAW264.7巨噬细胞,分为空白对照组(基础培养液)、FFA组(基础培养液中加入FFA,终浓度为100μmol/L)和京尼平组(基础培养液中加入京尼平,终浓度为10μmol/L)。用Western blot的方法检测药物干预后UCP2与NF-κB磷酸化的表达水平。结果显示,与空白对照组相比,FFA作用于巨噬细胞24h后细胞内UCP2与NF-κB磷酸化水平均升高,差异有统计学意义(P<0.05);而京尼平作用于巨噬细胞24h后细胞内UCP2与NF-κB磷酸化水平均降低,差异有统计学意义(P<0.05)。由此可知,FFA能诱导巨噬细胞的线粒体发生解耦连,NF-κB磷酸化水平升高。     

盐酸溶液中dmit(Bu~n)_2对Q235钢的缓蚀性能研究

合成了有机硫化合物4,5-二(正丁硫基)-1,3-二硫杂环戊二烯-2-硫酮(dmit(Bun)2),用元素分析和红外光谱进行了表征,采用电化学极化曲线法研究了dmit(Bun)2在1.0 mol·L-1HCl溶液中对Q235钢的缓蚀作用,并考察了dmit(Bun)2浓度、HCl浓度、腐蚀体系温度、缓蚀液放置时间对缓蚀性能的影响。研究结果表明:在30℃时,dmit(Bun)2浓度为80 mg·L-1的1.0 mol·L-1HCl溶液中,缓蚀剂对Q235钢的缓蚀率达到了99.01%,dmit(Bun)2为混合型缓蚀剂。吸附拟合表明:dmit(Bun)2在Q235钢表面的吸附符合Langmuir吸附等温式,属于自发进行的化学吸附。dmit(Bun)2的缓蚀率随dmit(Bun)2浓度增大而升高,随腐蚀体系温度升高而降低,随HCl浓度增大而逐渐降低,随静置时间的延长、dmit(Bun)2的缓蚀性变化不大。     

从含Sn,Zn,Cu,Pb,In的盐酸溶液中用TBP萃取Sn

文题的最佳工艺条件为:25%TBP-10%癸醇-65%煤油,3mol/LHCl,20～30℃。负载有机相中的杂质离子Zn~(2+),Cu~(2+),In~(3+),Pb~(2+)用约5mol/L盐酸洗涤除去。负载有机相中的Sn~(4+)用0.24mol/L HCl反萃。萃取及反萃取的理论级数分别为2和7级。     

锰结核的选择沥取法研究

用1.5 mol/l HOAc,1.5 mol/l HOAc-1.0 mol/l NH_2OH·HCl(v/v1:1),6 mol/l HCl 和 HF-HCl 作沥取剂,选择沥取锰结核的不同地球化学相中的元素,并用等离子体原子发射光谱法分析了各相的化学组成,用放化技术测量了各相的铀系核素。结果表明,碳酸盐、吸附态元素及大部分U同位素存在于HOAc 相,Fe-Mn 氧化物矿物,Cu,Co,Ni,V 等元素及~(226)Ra,~(210)Pb存在于 NH_2OH·HCl 相,HCl 相由富Ti 和Th 的矿物及Fe 的稳定矿物(如针铁矿)组成,而 HF-HCl 相则是富 Si 和Al的铝硅酸盐,包括粘土矿物和碎屑矿物。     

黄粉虫虫粕中甲壳素的提取工艺

采用酸碱法从黄粉虫幼虫脱油脂后的干燥虫粕中提取甲壳素,通过正交试验设计对提取工艺进行优化。结果表明,HCl的质量分数和Na OH的质量浓度、浸泡时间、浸泡温度、提取剂用量对虫粕甲壳素的提取有较大的影响,其影响程度按照由大到小的顺序依次为:HCl浸泡时间,HCl浸泡温度,HCl的质量分数,提取剂用量;Na OH的质量浓度,浸泡温度,浸泡时间,提取剂用量。提取黄粉虫虫粕中甲壳素的最优工艺条件为:酸浸时间2.5 h,酸浸温度80℃,质量分数为0.08的HCl,提取剂用量15 m L·g~(-1);碱浸时间3 h,碱浸温度80℃,质量浓度为60 g·L~(-1)的Na OH,提取剂用量20 m L·g~(~(-1))。制得的产品为白色片状固体,灰分的质量分数为0.006 7,剩余蛋白的质量分数为0.020 3 mg·g~(-1)。产品提取率为13%。     

采用软化学法制备WO3和其锂化物及其结构稳定性的研究

通过两种方法合成了六方形和单斜氧化钨的水化物WO3·yH2O(y=0.50～1.20):(1) 用强酸(1～3 mol/L HCl) 将0.25 mol/L Li2WO4在100 ℃进行酸化; (2) 将1 mol/L Li2WO4置于高压反应釜中,控制pH为1.5,在100 ℃进行水热合成. 对于水热法,温度较高时(125～200℃),得到组分为LixWO3+x/2·yH2O(x=0.10～0.50,y=0.50～0.90)的锂化氧化钨. 合成产物的结构和组分与酸的浓度和后处理(加热、超声波)有关. 在350 ℃加热时六方形氧化钨完全转化为单斜氧化钨. 将温度在150 ℃以上时通过水热法合成的氧化钨前驱体进行超声波处理,产物的含锂量恒定为每单元0.18摩尔. 锂的引入有利于锂化氧化钨的结构和组分的稳定.     

发酵产物对灰绿曲霉β-葡萄糖苷酶活力的影响

从自行筛选出的灰绿曲霉XC-9菌株的发酵液得到活力较高的纤维素酶,分离纯化出其中的β-葡萄糖苷酶(BG).探讨发酵产物对酶活力的影响,乙醇、乙酸、乳酸对酶活力有不同程度抑制,抑制强度依次为乳酸乙酸乙醇,其半抑制浓度(IC50)分别为0.09,0.34和4.4mol/L.它们对BG的抑制作用均表现为非竞争性可逆抑制,抑制常数分别为0.7%(0.083mol/L)、2%(0.315mol/L)、26%(4.25mol/L),实验结果表明它们不是结合在酶活性中心的底物结合部位上,而是结合在其以外的必需基团上抑制酶活力.随着乙醇浓度上升,BG最适反应温度逐渐降低,乙醇达到20%(体积分数,下同)时,BG最适温度由60℃降到50℃.在低体积分数乙醇溶液(小于16%)中的BG活力高过无乙醇溶液中的BG活力.荧光光谱分析表明,高浓度乙醇可使BG分子构象松散,导致变构失效.该研究为纤维素酶发酵进程控制提供了理论依据.     

壳聚糖稳定性及抑菌作用研究

研究壳聚糖在不同处理条件下,其稳定性和抑菌作用的变化;以大肠杆菌和金黄色葡萄球菌作为实验菌种,主要考察的影响因素包括:壳聚糖浓度(壳聚糖浓度范围0～20 g/L)、温度(冰浴,25℃,60℃,121℃)、金属离子种类(NaCl,MgCl_2,FeCl_3)和浓度(0. 1 mol/L,0. 2 mol/L,0. 3 mol/L,0. 4 mol/L,0. 5 mol/L)、酸溶剂(HAc、HCl、柠檬酸),滤纸片琼脂扩散法测定各影响因素下,壳聚糖的稳定性及抑菌作用的变化;结果表明:随着壳聚糖浓度的增加,抑菌作用逐渐增强;不同温度下,壳聚糖均能保持较好的稳定性;金属离子种类和浓度对壳聚糖的性能有一定的抑制作用;不同酸溶剂溶解壳聚糖时,其稳定性和抑菌作用存在一定的差异。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that