3,4-二硝基呋咱基氧化呋咱的比热容、热力学性质、绝热至爆时间及热感度概率密度分布

应用Micro-DSCⅢ微热量仪对3,4-二硝基呋咱基氧化呋咱(DNTF)进行比热容测定, 得到了DNTF比热容随温度变化的线性方程定压cp=0.31064＋2.109×10-3T (285 K相似文献   

尿嘧啶和5-溴尿嘧啶的低温热容

采用综合物性测量系统(PPMS)的热容测量模块在1.9-300 K温度区间内对两种药物中间体(尿嘧啶和5-溴尿嘧啶)的低温热容进行了测量与研究. 结果表明, 在测量温区内两种化合物的低温热容随温度的上升而逐步增加, 无任何热异常现象产生; 在相同温度下, 5-溴尿嘧啶的热容数值始终高于尿嘧啶. 利用低温热容理论模型对热容数据进行了拟合, 并计算得到了0-300 K温区的摩尔熵变、焓变等热力学函数. 此外, 通过热容拟合数据计算得到的尿嘧啶和5-溴尿嘧啶在298.15 K的标准摩尔规定熵分别为(132.48±1.32)和(165.39±1.65) J·K^-1·mol^-1.     

Ag3PO4微晶表面热力学函数的温度及形貌效应

在室温下采用离子交换法制备了四足状、 立方体状和十二面体状Ag₃PO₄微晶及Ag₃PO₄块体, 并进行了表征. 以Ag₃PO₄微/纳米和块体材料热力学性质的区别为基础, 结合化学热力学理论和热动力学基本原理, 导出摩尔表面热力学关系式. 在此基础上, 采用原位微量热技术获取Ag₃PO₄的化学反应动力学信息和表面热力学函数, 讨论了形貌和温度对表面热力学性质变化的影响. 结果表明, 四足状Ag₃PO₄的摩尔表面焓(\begin{array}{c}{H}_m^s\end{array})、 摩尔表面Gibbs自由能(\begin{array}{c}{G}_m^s\end{array})和摩尔表面熵(\begin{array}{c}{S}_m^s\end{array})最大, 立方体状次之, 十二面体状最小; \begin{array}{c}{H}_m^s\end{array}和\begin{array}{c}{S}_m^s\end{array}随温度的升高而增大, \begin{array}{c}{G}_m^s\end{array}则随温度的升高而减小.     

镥晶体的绝热量热法测试和热力学函数

文章合成了Lu(NO₃)₃(C₂H₅O₂N)_4.H₂O,用红外和元素分析对其进行了表征。用高精度全自动绝热量热仪,测定了该配合物80-382 K温区的热容, 利用实验热容数据, 根据热容与焓、熵的热力学关系, 求出了配合物85-350 K温区内每隔5 K相对于298.15K的标准热力学函数(HT - H298.15)m和(ST - S298.15)m.在80-350 K温度区间内,配合物的热容随温度升高而增大,没有相转移点和热力学吸收峰的出现,该配合物在此温度区间内是稳定存在的。     

气体节流膨胀过程的热力学分析

探讨气体节流膨胀过程中的熵(S)的变化,指出任何气体的节流膨胀都是熵增过程,并且是不可逆的。在此基础上,讨论和总结了节流膨胀过程的全部热力学特征。     

不同形貌Ag_3PO_4的表面自由能及原位光催化过程的热力学和动力学参数

<正>目前,在利用表面能研究纳米催化剂形貌效应时,多以催化剂表面原子排布或不同晶面的夹角与密勒指数间的关系来定性描述表面能高低[1,2],或利用密度泛函理论对表面能进行理论计算[3,4],但其数值可能会因计算方法和模型不符而与真实值存在偏差,而表面能的实验测定至今仍无精确、可靠、通用的方法[5].因此发展一种准确获取表面能的普适性方法并与材料的催化性能相关联非常必要.微量热技术能对体系变化过程进行实时监测,通过体系变化过程的热力学和动力学参数获取纳米材料的     

改性蔗髓重金属吸附剂去除水中Cr(Ⅵ)的动力学研究

对甘蔗渣预处理后以Na OH和二硫化碳改性转型合成重金属吸附剂。实验结果表明,改性后蔗髓纤维(MSCB)投加量为4 g/L,对50 mg/L Cr(Ⅵ)的最大吸附量为9.8 mg/g,平衡时间为30~60 min,去除率达98.05%,出水浓度0.78 mg/L,比改性前蔗髓纤维对Cr(Ⅵ)的吸附率(23.7%)提高了74.35%。MSCB对Cr(Ⅵ)的吸附进行Langmuir与Freundlich等温吸附方程拟合,更符合Langmuir单分子化学吸附;对吸附动力学拟合模型分析,吸附过程更符合准二级速率方程;吸附热力学模型显示该吸附为自发进行的吸热反应且是熵增过程。     

烷基链工程对两亲有机半导体热力学性能影响的研究

Due to their special polar structure, amphiphilic molecules are simple to process, low in cost and excellent in material properties. Thus, they can be widely applied in the preparation of functional film materials and bionics related to cell membranes. Therefore, amphiphilic organic semiconductor materials are receiving increasing attention in research and industrial fields. The structure of organic amphiphilic semiconductor molecules usually consists of three functional parts: a hydrophilic group, a hydrophobic group, and a linking group between them. The adjustment of their correlation to achieve the target performance is particularly important and needs experimental discussion regarding synthetic methodologies. In this work, we focused on the engineering of a substituent alkyl-chain, and an amphiphilic functional molecule (benzo[b]benzo[4, 5] thieno[2, 3-d]thiophene, named C_nPA-BTBT, n = 3–11) was proposed and synthesized. This molecule links the hydrophobic semiconductor backbone and hydrophilic polar group through alkyl chains of different lengths. Fundamental properties were investigated by nuclear magnetic resonance (NMR) and ultraviolet-visible spectroscopy (UV-Vis) to conform the structure and the band gap properties of the designed organic semiconductor. Thermodynamic features were investigated by thermogravimetric analysis (TGA) and corresponding differential thermal gravity (DTG), which indicate that the functional molecule C_nPA-BTBT (n = 3–11) has a great stability in ambient conditions. Moreover, the results show that the binding ability of the amphiphilic molecule to water molecules was regulated by the odd-even alternating effect of the alkyl chain and the intramolecular coupling with BTBT. Furthermore, differential scanning calorimetry (DSC) and polarized optical microscopy (POM) were used to study the material properties in detail. As the length of the alkyl chain increased, the functional molecule C_nPA-BTBT (n = 3–11) gradually changed from "hard" species with no thermodynamic changes to a transition one with a pair of thermodynamic peaks, and eventually to a "soft" one as a typical liquid crystal with clear observation of Maltese-cross spherulites. The cooling and freezing points were further studied, and the values and trends of their enthalpy and corresponding temperature fluctuated and alternated due to the volume effect, odd-even alternating effect, flexibility, and other functions of the alkyl chain. Three molecular models were proposed according to the thermodynamic study results, namely the brick-like model, transition model, and liquid crystal model. This work presents in-depth discussion on material structure and corresponding thermodynamic properties, and it is an experimental basis for the design, synthesis, optimization, and screening of target performance materials.     

硅钨杂多酸与牛血红蛋白相互作用的研究

多金属氧酸盐作为抗艾滋病病毒、抗流感病毒和抗肿瘤的药物,引起了人们对多金属氧酸与蛋白质之间相互作用的极大关注。蛋白质空间结构的任何变化引起的构象变化都意味着蛋白质分子的活性改变,因此,蛋白质与内源性化合物及许多药物分子之间相互作用的研究一直受到人们关注[1￣3]。血红蛋白是动物及人体内执行输氧任务的蛋白质,是生命机体进行各种生理活动的主要承担者。血红蛋白分子中每条α链和β链含有的色氨酸(Trp)残基分别为α-14Trp、β-15Trp、β-37Trp。Alpert[4]等认为位于疏水腔内的β-37Trp是血红蛋白内源荧光的主要来源,同时β…     

碱金属及碱土金属离子化合物溶解性变化规律

对碱金属、碱土金属离子化合物的溶解性与正负离子半径差Δr的变化关系进行了探讨,总结出碱金属、碱土金属同族化合物溶解性随Δr的变化有以下3种情况:(1)随Δr增大,溶解度s随之增大;(2)随Δr增大,s反而减小;(3)随Δr增大,s变化不规则。在此基础上,通过碱金属、碱土金属同族化合物晶格能U、离子水合焓ΔHh、溶解过程的焓变ΔHs和自由能变ΔGs等热力学量的递变对其溶解性随Δr的变化作出了解释。