医用hfc-134a中微量杂质的定性、定量分析

气相色谱;医用hfc-134a;定性分析;定量分析     

HFC-227ea的维里系数研究

ＨＦＣ－２２７ｅａ是一种有希望的新环保制冷剂,特别是作为混合物中的一种组元用于Ｒ２２和Ｒ５０２的替代,但其热物性数据十分有限。本文使用膨胀定容法高精度地测量了ＨＦＣ－２２７ｅａ的气相ＰＶＴ性质,沿定温线外推确定了其第二和第三维里系数,并与文献值进行了比较;使用截断维里方程,根据本文所确定的维里系数,可以高精度地再现ＨＦＣ－２２７ｅａ的气相区热力性质。     

Robust μ -stability for uncertain stochastic neural networks with unbounded time-varying delays

In this paper, we investigate the global robust stability for uncertain stochastic neural networks with unbounded time-varying delays and norm-bounded parameter uncertainties. A new concept of global robust μ-stability in the mean square for neural networks is given first, then by means of the linear matrix inequality (LMI) approach, stability criteria are presented. Several corollaries are also derived. A simple example is presented to demonstrate the effectiveness of the main result.     

一种HCFC-22新型替代制冷剂的实验研究

本文提出采用三元混合工质HFC—161/HFC-125/HFC-32作为HCFC-22替代制冷剂。在空气-水热泵实验台上对该工质及HCFC-22、 R407C进行对比实验,结果表明,在不改动任何系统部件的前提下,该新型制冷剂的COP值大于HCFC-22主要替代制冷剂R407C,在较高的进风温度或较低的进水温度下, COP值接近甚至大于HCFC-22。此外,该三元混合物还具有GWP值小、排气温度低、温度滑移小的优点,是HCFC-22一种有前途的替代物。     

Isothermal vapor–liquid equilibrium data for the binary mixture ethyl fluoride (HFC-161) + 1,1,1,2,3,3,3-heptafluoroproane (HFC-227ea) over a temperature range from 253.15 K to 313.15 K

Vapor–liquid equilibrium (VLE) data for the refrigerant mixture ethyl fluoride (HFC-161) + 1,1,1,2,3,3,3-heptafluoroproane (HFC-227ea) are reported in the temperature range from 253.15 K to 313.15 K with a single-phase circulation vapor–liquid equilibrium still. The results of the correlation for the vapor–liquid equilibrium data with Peng–Robinson (PR) equation of state (EOS), combined with the first Modified Huron-Vidal (MHV1) mixing rule and Wilson model, are presented. These results are in a good agreement with experimental data. The average and maximum derivations of vapor molar composition are within 0.0130 and 0.0295 respectively, and the average and maximum relative derivations of pressure are within 1.04% and 2.96%, respectively. The model parameters, determined from these binary data, are given to predict the phase behavior for a later ternary system. The binary system HFC-161 + HFC-227ea is a non-azeotropic mixture and exhibits a negative deviation from Raoult's law.     

HFO-1234yf与HFC-134a比较分析

总结了HFO-1234yf的最新研究成果,对比分析了HFO-1234yf和HFC-134a的热物性参数及实验表现,结果表明两者的热物性参数及实验表现非常相似,HFO-1234yf是较好的替代制冷剂之一。为了更好的评价该制冷剂,还需要进行全面的热物性测试。     

HFC-227ea液相黏度和密度的实验研究

利用振动弦黏度／密度计对1,1,1,2,3,3,3七氟丙烷（HFC-227ea）的黏度和密度进行了实验研究,温度范围为243．15-363．15K,压力范围为0．54-11．49MPa,黏度和密度实验测量的不确定度分别为4-2％和4-0．2％。利用获得的实验数据分别拟合了HFC-227ea黏度和密度方程。黏度实验数据与...     

On fractional powers of generators of fractional resolvent families

We show that if −A generates a bounded α-times resolvent family for some α∈(0,2], then −Aβ generates an analytic γ-times resolvent family for and γ∈(0,2). And a generalized subordination principle is derived. In particular, if −A generates a bounded α-times resolvent family for some α∈(1,2], then −A1/α generates an analytic C₀-semigroup. Such relations are applied to study the solutions of Cauchy problems of fractional order and first order.     

Hyperbolic topology of normed linear spaces

In a previous paper [H. Tsuiki, Y. Hattori, Lawson topology of the space of formal balls and the hyperbolic topology of a metric space, Theoret. Comput. Sci. 405 (2008) 198–205], the authors introduced the hyperbolic topology on a metric space, which is weaker than the metric topology and naturally derived from the Lawson topology on the space of formal balls. In this paper, we characterize spaces L_p(Ω,Σ,μ) on which the hyperbolic topology induced by the norm _p coincides with the norm topology. We show the following:

(1) The hyperbolic topology and the norm topology coincide for 1<p<∞.

(2) They coincide on L₁(Ω,Σ,μ) if and only if μ(Ω)=0 or Ω has a finite partition by atoms.

(3) They coincide on L_∞(Ω,Σ,μ) if and only if μ(Ω)=0 or there is an atom in Σ.