首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 140 毫秒
1.
BaCe0.95Y0.05O3α固体电解质材料的热性质   总被引:2,自引:0,他引:2  
用甚高温量热计对BaCe0.95Y0.05O3-α固体电解质材料在300-1400℃范围做差热分析,证明其结构是稳定的。在1000-1500℃范围做焓测定,得到焓与温度的关系H=-6598+1.45(J.g^-1)及平均热容c=1.45J.(gK)^-1。  相似文献   

2.
测定了饥饿状态下中华鳖(Trionyxsinensis)幼鳖在水中的呼吸代谢及其与温度、体重的关系。体重16~150g的幼鳖在水温28℃下的个体耗氧率R可表示为:lg(R/mL·h-1)=0.6314lg(W/g)-1.0549(W为个体湿重);r=0.91,n=26,P<0.001,这时幼鳖的单位体重耗氧率V与体重呈如下负相关关系:V=88.1254W-0.3686;r=0.80,n=26,P<0.001.中华鳖能够正常活动、摄食的温度范围为20~35℃。20,24,26,28,30,32,35℃下30~60g幼鳖水中呼吸耗氧率的变动范围为24.37~31.20mL·k-1·h-1.t检验表明温度对鳖在水中的呼吸没有显著影响.  相似文献   

3.
采用流动注射技术,研究了由Jones柱产生的铁(Ⅱ)与光泽精的化学发光反应,建立了新的测定铁的化学发光分析法.方法的检出限为4×10-12g/mL铁,相对标准偏差为2.0%(2×10-8g/mL铁,n=11),线性范围为1×10-11g/mL~1×10-5g/mL.该法用于一些化学试剂和镁合金中痕量铁的测定,结果令人满意.  相似文献   

4.
在TritonX-100存在下,pH=5.0~5.5时,新试剂Cl-RACP与银生成配合物,其最大吸收波长为500nm,配合物的配位比为1:2,表观摩尔吸光系数为1.1×10 ̄5·L·mol ̄(-1)·cm ̄(-1)。Ag(Ⅰ)的浓度在0~2.0μg·ml ̄(-1)范围内符合比尔定律。该法用于阳极泥和废定影中银的测定,结果较满意,相对标准偏差为1%。  相似文献   

5.
研究了在吐温-80存在下,铅(II)与合成的1-[(5-溴-2-吡啶)偶氮]-2,7-萘二酚(简称5-Br-PADN)的显色条件和光度特性。非离子表面活性剂吐温-80主要起增溶作用。显色反应在50℃时10min内即可完成,配合物在pH3.0~6.0之间的吸光度大而稳定,最大吸收波长λmax=590nm,摩尔吸光系数ε_(590)=8.31×10 ̄4L·mol ̄(-1)·cm ̄(-1).Pb ̄(2+)含量在0~20μg·(25×10 ̄(-3)L) ̄(-1)范围内遵守比尔定律。拟定方法的选择性较好,已用于树叶表面上和人发中铅的测定,获满意结果。  相似文献   

6.
在pH6.30、37℃条件下,采用离心超过滤技术测定了11种稀土离子(Ⅲ)与牛血清白蛋白(B8A)的专一性结合常数K_s和非专一性结合常数K_(ns)观察到K_s随稀土系列原子序数(Z_(RE))的变化有明显的"四分组效应"和"钆断现象",而K_(ns)~Z_(RE)类似于一元羧酸-稀土配合物稳定常数的变化规律。求出Tb(Ⅲ)-BSA结合反应的热力学函数分别为ΔH_s=44.5±0.8kJ/mol,ΔS_s=243.2±2.4Jmol·K,ΔH_(ns)=19.9±1.1KJ/mol,ΔS_(ns)=141.4±3.2J/mol·K。根据不同pH下测得的Tb(Ⅲ)与BsA结合的K_s和K_(ns)拟合出BSA分子中参与稀土配位的基团的质子解离常数pK=4.60,进而确定出这些基团主要为天冬氨酸和谷氨酸残基侧链中的β、γ-COO ̄-。  相似文献   

7.
1,10-菲罗啉-5,6-二醌伏安行为研究   总被引:1,自引:0,他引:1  
在0.50mol·L~(-1)NH_3-NH_4Cl缓冲溶液中,1,10-菲罗啉-5,6-二醌有一还原伏安峰。当静止富集2min,v=100mV·s~(-1)时,其峰电位E_p=-1.31V(vs.Ag/AgCl)。用线性扫描和循环伏安法等手段研究体系的伏安行为,特别是吸附性。实验表明,该体系属具有吸附性的不可逆过程。用于单扫示波极谱法测定,线性范围为5.0×10~(-8)~5.0×10~(-6)mol·L~(-1),其相关系数为0.9995。  相似文献   

8.
研究Twen水溶液中硫氰酸铋(Ⅲ)配合物的吸收光谱,得到λmax=470nm,较DMSO、水介质中显色反应的灵敏度提高一倍.在显色条件pH=0.66,I=0.32下,硫氰酸铵浓度在0.20~0.32molL-1范围内Δε与硫氰酸铵浓度呈函数关系.用改善了的Yatsimirskis方法处理数据,得到β1=0.857,β2=3.20,β3=4.09,β4=7.50及Δε1=1.60×103,Δε2=5.78×103,Δε3=4.44×103,Δε4=7.34×103.并测出显色反应的热力学参数ΔH=-117.8kJmol-1,ΔG=-5.06kJmol-1(t=25℃).  相似文献   

9.
在pH5.0的HOAc-NaOAc缓冲溶液中,当有0.10%SLS存在时,Ag(I)与QARH形成1:1络合物,λ_(max)为535nm,ε为1.05×10 ̄5L·mol ̄(-1)·cm ̄(-1),Ag(I)含量在0.005~1.00μg/mL范围内服从Beer定律,稳定常数为1.78×10 ̄(15).所提出的方法用于精铜矿中微量银的测定,结果满意  相似文献   

10.
研究了非对称性5,10,15-三(4-甲基-3-磺基苯)-20-[4-(5-氟尿嘧啶)-3-磺基苯]卟啉(MFuSPP)测钯的显色条件,在表面活性剂十二烷基磺酸钠存在下,pH4.5 ̄6.0的弱酸性HAc ̄NaAc缓冲介质中,用抗坏血酸催化,Pd(Ⅱ)与MFuSPP形成1:1配合物,最大吸收波长415nm,摩尔吸光系数ε=1.8×10^5L·mol^-1·cm^-1,线性范围0 ̄2.0μg/10ml  相似文献   

11.
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.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
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.  相似文献   

14.
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.  相似文献   

15.
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。  相似文献   

16.
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.  相似文献   

17.
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.  相似文献   

18.
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-  相似文献   

19.
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-  相似文献   

20.
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  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号