基于M-QSPR的乙醇-汽油参比燃料混合物辛烷值的理论预测

从分子结构角度出发,针对乙醇-汽油参比燃料混合物的辛烷值开展混合物的定量结构-性质相关性(M-QSPR)研究,建立相应的理论预测模型。采用原子碎片描述符对乙醇-汽油参比燃料混合体系的结构特征进行表征,应用遗传-多元线性回归算法从上述描述符中优化筛选出与其辛烷值最为密切相关的特征结构描述符,建立相应的两参数线性预测模型。模型复相关系数为0.987,预测平均绝对误差为1.478。模型内外部验证及稳定性分析结果表明,所建模型具有较强的稳健性及外部预测能力。对模型进行机理解释,揭示了影响乙醇-汽油参比燃料混合物辛烷值的特征结构因素及其影响规律。该研究为工程上提供了一种根据分子结构预测乙醇-汽油参比燃料混合物辛烷值的新方法。

二元互溶可燃混合液体闪点预测模型研究

基于定量结构-性质相关性(QSPR)原理,开展二元互溶可燃混合液体闪点与其结构信息间的内在定量关系(M-QSPR)研究。以332个不同组成和配比的二元互溶可燃混合液体闪点试验数据作为研究样本,根据体系中各纯组分的结构信息,计算相应的混合物描述符(SiRMS,Simplex Representation of Molecular Structure),应用遗传-多元线性回归(GA-MLR)算法从中优化筛选出一组与该体系闪点最密切相关的原子碎片参数作为输入参数,分别采用多元线性回归(MLR)和支持向量机(SVM)算法建立理论预测模型,并将其与文献已有模型进行比较。结果表明,MLR和SVM对测试集样本的平均绝对误差(AAE)分别为4.142 K、1.551 K,均方根误差(RMSE)分别为4.911 K、2.220 K,决定系数(R^2)分别为0.818、0.962。研究表明,影响二元混合液体闪点的主要SiRMS结构因素是■和■,并且随体系中■、■、■四原子碎片增多,闪点升高;随体系中■、■、■四原子碎片增多,闪点降低。同时,与内部交互作用和分子间非加和作用相比,分子间的可加和作用对该体系闪点的影响更为显著;与原子的局部电荷相比,原子类型对该体系闪点的影响更为显著。

借助直角玻璃管开发化学实验的尝试

借助直角玻璃管和某些常规仪器,设计并开发了混合物性质、生成白烟、氢气性质等化学实验。新开发的实验设计新颖、装置简约、操作方便、现象明显、结论可靠,取得了良好的教学效果。

车用涡旋空调压缩机含油量优化

讨论了车用空调压缩机介质含油量各种热力参数的计算方法,分析了含油量对压缩机性能的影响,运用优化的方法得出了不同工况下介质含油的最佳值,为车用空调压缩机安全经济的运行提供了一个含油量的科学选择方法。

Determination of Transport Properties of Dilute Binary Mixtures Containing Carbon Dioxide through Isotropic Pair Potential Energies

The present work is concerned with extracting information about intermolecular potential energies of binary mixtures of CO2 with C2H6, C3H8, n-C4Hlo and iso-C4Hlo, by the usage of the inversion method, and then predicting the dilute gas transport properties of the mixtures. Using the inverted pair potential energies, the Chap- man-Enskog version of the kinetic theory was applied to calculate transport properties, except thermal conductivity of mixtures. The calculation of thermal conductivity through the methods of Schreiber et al. and Uribe et al. was discussed. Calculations were performed over a wide temperature range and equimolar composition. Rather accurate correlations for the viscosity coefficients of the mixtures in the temperature range were reproduced from the pre- sent unlike intermolecular potential energies. Our estimated accuracies for the viscosity are within ±2%. Acceptable agreement between the predicted values of the viscosity and thermal conductivity with the literature values demon- strates the predictive power of the inversion scheme. In the case of thermal conductivity our results are in favor of the preference of Uribe et al.＇s method over Schreiber et al.＇s scheme.

PEGylation of Hirudin and Analysis of Its Antithrombin Activity in vitro

Hirudin is the most anticoagulant drug found in nature, but its short serum half-life significantly inhibits its clinical anpplication. The PEGvlation of hirudin, the most promising anticoagulant drug, was performed in this paper. The optimal reaction conditions for PEG ylated hirudin were investigated, wh.en the PEGylation react, on.wasconducted under 4℃ after 10h, in the borate buffer at pH 8.5 .with the molar ratio 230 ： 1 of PEG to hirudin, a higher modification extent was achieved. Finally, the bioactivity of PEGylated hirudin was measured in vitro.Compared with unmodified hirudin, 26% of anti-thrombin activity was retained.

Phenomenology of Friedberg-Lee Texture in Left-Right Symmetric Model

We consider that the Higgs triplet Yukawa coupling takes the Friedberg-Lee texture, and the Higgs doublet Yukawa coupling simply identifies with the diagonal Yutawa coupling of charged lepton in the context of left-right symmetric model. In this scenario, the phenomenology, including effective neutrino masses, mixings, and thermal flavor-dependent leptogenesis and lepton flavor violation decays are studied. We investigate the combined constrain of the parameters in this scenario and test its consistency with present data.

Prediction of Volumetric Properties(p-v-T)of Natural Gas Mixtures Using Extended Tao-Mason Equation of State

A statistical-mechanical-based equation of state(EOS)for pure substances,the Tao-Mason equation of state,is successfully extended to prediction of the(p-v-T)properties of fourteen natural gas mixtures at temperatures from 225 K to 483 K and pressures up to 60.5 MPa.This work shows that the Tao-Mason equation of state for multicomponent natural gas is predictable with minimal input information,namely critical temperature,critical pressure,and the Pitzer acentric factor.The calculated results agree well with the experimental data.From a total of 963 data of density and 330 data of compressibility factor for natural gases examined in this work,the average absolute deviations(AAD)are 1.704%and 1.344%,respectively.The present EOS is further assessed through the comparisons with Peng-Robinson(PR)equation of state.For the all of mixtures Tao-Mason(TM)EOS outperforms the PR EOS.

Improvement of Emissions and Burning Limits in Burner Combustion using an Injector on the Concept of Fuel-Water Internally Rapid Mixing

This study tried to apply biomass fuel to clean burner combustion under high load conditions by water addition. A newly developed injector mixes fuel rapidly with water inside of the injector with support of atomizing air. The mixture composed of three-fluid is injected as spray into a flame stabilizer of burner. Investigation of emission performance of this injector shows that the internally rapid mixing type of injector is hopeful technique to introduce water into burner combustion. Combustion by this injector emits exceedingly less particulate matters at high load. NOx emission is strongly dependent on water flow rate.

Influence of water content and shear rate on the mechanical behavior of soil-rock mixtures

Soil-rock mixtures(S-RMs) are widely distributed in the nature. The mesoscopic deformation and failure mechanisms as well as the macro-mechanical behaviors of the S-RMs depend largely upon the rate of deformation, water content and particle sizes. In this research, a series of large-scale direct shear tests with different water contents and different grain-size distributions were conducted to study the influence of the aforementioned factors on the mechanical properties of the S-RMs. Due to the effect of the rock blocks' breakage in the S-RMs, the relationship between the shear strength and the vertical stress of S-RM follows a power law instead of a linear one. It is found that there exists a threshold value for the vertical stress during the shearing process,below which the soil strength is mainly determined by the inter-locking of particles and the re-arrangement of meso-structure,and otherwise large-sized rock blocks are gradually broken into smaller fragments, resulting in a decrease in the soil strength.The shear rate can also significantly influence the degree of particle breakage and the meso-structural rearrangement of the SRMs, namely, under low shear rate, the particles of the samples are fully broken resulting in enhanced macro-strength. As a result, the lower the shear rate, the higher the macroscopic strength. So under unsaturated conditions, the water content will affect the strength of the S-RMs by reducing the strength of rock blocks. As the water content increases, the soil strength decreases gradually, and assumes a moderate value when the water content reaches 8%. At the same water content, the soil strength increases with the sizes of large rock blocks. For the occlusion, breakage and structure re-arrangement of the oversized rock blocks inside S-RM, which have a huge influence on the mechanical characteristics of the samples.

Comparison of luminescent properties of helicene-like bibenzothiophenes with o-carborane and 5,6-dicarba-nidodecaborane

This article describes comparison of the anchoring effect on electronic properties of the helicene-like bibenzothiophene between o-carborane and 5,6-dicarba-nido-decaborane. The o-carborane and nido-decaborane-fused bibenzothiophenes were simultaneously obtained in the same reaction and successfully isolated. Initially, the X-ray single crystal analysis revealed that the helicene-like distorted structure was realized in the nido-decaborane-fused bibenzothiophene. From optical measurements in the solution state, distinct different characteristics depending on the type of anchors were observed. It was summarized that the absorption and luminescent properties originated from weak π-conjugation at the bibenzothiophene moiety in the o-carboranefused compound were obtained, whereas robust π-conjugation and significant emission from the intramolecular charge transfer state were detected from the nido-decaborane-fused compound. These data can be explained by the theoretical results that π-conjugation was restrictedly developed within the bibenzothiophene moiety in frontier orbitals of the o-carborane-fused compound. In contrast, π-conjugation can be constructed even through the distorted bibenzothiophene because of the nido-decaborane unit. Moreover, the intramolecular charge transfer state should be realized because of electronic interaction involving the nido-decaborane unit in the excited state. Furthermore, it was demonstrated that the nido-decaborane-fused compound possessed solid-state emission and mechanochromic luminescent properties. The π-conjugation on the distorted structure supported by the nido-decaborane anchor should play a significant role in suppressing aggregation-caused quenching followed by presenting solid-state emission with stimuli responsiveness.

Non-phospholipid liposomes with high sterol content display a very limited permeability

We demonstrate that it is possible to form non-phospholipid fluid bilayers in aqueous milieu with a mixture of palmitic acid (PA),cholesterol (Chol),and cholesterol sulfate (Schol) in a molar proportion of 30/28/42.These self-assemblies are shown to be bilayers in the liquid ordered phase.They are stable between pH 5 and 9.Over this pH range,the protonation/deprotonation of PA carboxylic group is observed but this change does not appear to alter the stability of these bilayers,a behavior contrasting with that observed for binary mixtures of PA/Chol,and PA/Schol.The multilamellar dispersions formed spontaneously from the PA/Chol/Schol mixture could be successfully extruded to form Large Unilamellar Vesicles (LUVs).These LUVs show interesting permeability properties,linked with their high sterol content.These non-phospholipid liposomes can sustain a pH gradient (pH internal 8/pH external 6) 100 times longer than LUVs made of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and cholesterol,with a molar ratio of 60/40.Moreover,the non-phospholipid LUVs are shown to protect ascorbic acid from an oxidizing environment (1 mM iron(III)).Once entrapped in liposomes,ascorbic acid displays a degradation rate similar to that obtained in the absence of iron(III).These results show the possibility to form novel nanocontainers from a mixture of a monoalkylated amphiphile and sterols,with a good pH stability and showing interesting permeability properties.

The physicochemical properties of some imidazolium-based ionic liquids and their binary mixtures

The density, viscosity and conductivity of ionic liquids （ILs）, 1-octyl-3-methylimidazolium tetrafluoroborate （[omim][BF4]）, 1-octyl-3-methylimidazolium chloride （[omim][C1]）, 1-hexyl-3-methylimidazolium tetrafluoroborate （[hmim] BF4]）, 1-hexyl- 3-methylimidazolium chloride （[hmim][C1]）, 1-hexyl-3-methylimidazolium hexafluorophosphate （[hmim][PF6]）, and the [omim][BF4] ＋ [omim][Cl], [hmim][BF4] ＋ [hmim][C1], and [hmim][PF6] ＋ [hmim][C1] binary mixtures were studied at dif- ferent temperatures. It was demonstrated that the densities of both the neat ILs and their mixtures varied linearly with temper- ature. The density sensitivity of a binary mixture is between those of the two components. The excess molar volumes （l/e） of [hmim][BF4] ＋ [hmim][C1] and [hmim][PF6] ＋ [hmim][C1] mixtures are positive in the whole composition range. For [omim][BF4] ＋ [omim][C1], the VE is also positive in the [omirn][C1]-rich region, but is negative in the [omim][BF4]-rich re- gion. The viscosity or conductivity of a mixture is in the intermediate of those of the two neat ILs. For all the neat ILs and the binary mixtures studied, the order of conductivity is opposite to that of the viscosity. The Vogel-Tammann-Fulcher （VTF） equations can be used to fit the viscosity and conductivity of all the neat ILs and the binary mixtures. The neat ILs and their mixtures obey the Fractional Walden Rule very well, and the values of the Walden slopes are all smaller than unit, indicating obvious ion associations in the neat ILs and the binary mixtures.

Realization approach of Pd-only three-way catalysts with high catalytic performance and thermal stability

Pd-only three-way catalyst （TWC）, Pd supported on washcoating （the mixture of alumina and Ce-Zr solid solution）/cordierite, was prepared and its catalytic performance and the operation window （2-value） at 450 ℃ were evaluated with the simulated automotive exhaust feed gas. Surfactants such as Tween-80 and Span-20 were added in the process of preparing the catalyst in order to improve the thermal stability and catalytic performance of Pd-only TWC. The fresh and aged catalysts at 1000 ℃ for 4 h were characterized by low-temperature N2 adsorption, XRD, XPS, and H2-TPR techniques. The results show that the presence of surfactants in the synthesis slurry could influence the physicochemical properties of the final Pd-only TWC. The FTS catalyst prepared with the mixed surfactant of Tween-80 and Span-20 exhibited excellent three-way catalytic performance. After being aged at 1000℃ for 4 h, the catalytic performances of Pd-only TWCs slightly decreased, but the FTS catalyst still demonstrated higher catalytic performance and better thermal stability compared with the Pd-only catalysts prepared with single surfactant or without any surfactant. And the FTS catalyst has a wider 2 value （operation window） than other catalysts, even after being aged at 1000℃.

Effects of Isotopic Concentrations on Thermodynamic Parameters of Deuterium-Tritium Mixtures

Thermodynamic estimation is still too much requested for scientific applications in spite of great advances in simulation methods for efficient determination of phase equilibrium of multi-component systems. In this work, thermodynamic properties of deuterium-tritium mixture in a wide range of temperatures and pressures have been predicted. Buckingham exp-6 potential has been utilized in calculations, based on statistical perturbation theory. The effects of various values of density, temperature and isotopic concentrations on pressure have been studied. Eventually, we have found out symmetrical effects of tritium concentration in deuterium-tritium mixtures.