The Effect of Pressure on the Dissociation of H_2/CH_4Gas Mixture during Diamond Films Growth via Chemical Vapor Deposition

Monte Carlo simulations are adopted to study the electron motion in the mixture of H2 and CH4 during diamond synthesis via Glow Plasma-assisted Chemical Vapor Deposition (GPCVD). The non-uniform electric field is used and the avalanche of electrons is taken into account in this simulation. The average energy distribution of electrons and the space distribution of effective species such as CH3, CH+3, CH+ and H at various gas pressures are given in this paper, and optimum experimental conditions are inferred from these results.

Solubility and mass transfer of H2, CH4, and their mixtures in vacuum gas oil: An experimental and modeling study

In this work,the solubility data and liquid-phase mass transfer coefficients of hydrogen(H2),methane(CH4)and their mixtures in vacuum gas oil(VGO)at temperatures(353.15-453.15 K)and pressures(1-7 MPa)were measured,which are necessary for catalytic cracking process simulation and design.The solubility of H2 and CH4 in VGO increases with the increase of pressure,but decreases with the increase of temperature.Henry’s constants of H2 and CH4 follow the relation of In H=-413.05/T+5.27 and In H=-990.67/T+5.87,respectively.The molar fractions of H2 and system pressures at different equilibrium time were measured to estimate the liquid-phase mass transfer coefficients.The results showed that with the increase of pressure,the liquid-phase mass transfer coefficients increase.Furthermore,the solubility of H2 and CH4 in VGO was predicted by the predictive COSMO-RS model,and the predicted values agree well with experimental data.In addition,the gas-liquid equilibrium(GLE)for H2+CH4+VGO system at different feeding gas ratios in volume fraction(i.e.,H285%+CH415%and H290%+CH410%)was measured.The selectivity of H2 to CH4 predicted by the COSMO-RS model agrees well with experimental data.This work provides the basic thermodynamic and dynamic data for fuel oil catalytic cracking processes.

Syntheses, Characterization and Biological Activity of Coordination Compounds of 3-Hydroxy-2-methyl-4<i>H</i>-pyran-4-one and Its Mixed Ligand Complexes with 1,2-Diaminocyclohexane

Coordination compounds of 3-hydroxy-2-methyl-4H-pyran-4-one with iron(III), cobat(III) and chromium(III) were synthesized with M:L (1:2). Mixed ligand coordination compounds of 3-hydroxy-2-methyl-4H-pyran-4-one and 1,2-diaminocyclohexane using the same metal ions were also synthesized M:L1:L2 (1:1:1) where L1 is 3-hydroxy-2-methyl-4H-pyran-4-one and L2 is 1,2-diaminocyclohexane. The coordination compounds obtained were characterized using electronic and infrared spectral analyses, magnetic susceptibility and percentage metal analysis. They were also evaluated for their cytotoxic and antioxidant activities. The result obtained suggested that octahedral geometry was obtained for all the compounds, as a result of additional two molecules of the solvent coordinated to the metal ions. Both the primary and secondary ligands coordinated in a bidentate fashion. The synthesized compounds exhibited moderate cytotoxicity, although none was as active as the standard. The cobalt(III) mixed ligand complex elicited the highest activity. The synthesized compounds all exhibited good to moderate antioxidant activity.

Preparation of activated carbons and their adsorption properties for greenhouse gases:CH_4 and CO_2

Three kinds of activated carbons were prepared using coconut-shells as carbon precursors and characterized by XRD, FT-IR and texture property test. The results indicate that the prepared activated carbons were mainly amorphous and only a few impurity groups were adsorbed on their surfaces. The texture property test reveals that the activated carbons displayed different texture properties, especially the micropore size distribution. The adsorption capacities of the activated carbons were investigated by adsorbing CH4, CO2, N2 and O2 at 25 ？C in the pressure range of 0-200 kPa. The results reveal that all the activated carbons had high CO2 adsorption capacity, one of which had the highest CO2 adsorption value of 2.55 mmol/g at 200 kPa. And the highest adsorption capacity for CH4 of the activated carbons can reach 1.93 mmol/g at 200 kPa. In the pressure range of 0-200 kPa, the adsorption capacities for N2 and O2 were increased linearly with the change of pressure and K-AC is an excellent adsorbent towards the adsorption separation of greenhouse gases.

青藏高原上空H_2O和CH_4的分布和变化趋势分析

采用UARS卫星1993—2004年卤素掩星试验的观测资料(HALOE),分析了青藏高原(下称高原)上空大气中H2O和CH4的分布和季节变化,也与同纬度其它地区作对比,找出它们的差异,并分析了H2O和CH4的多年变化趋势。结果表明:高原上空H2O混合比在对流层上层随高度迅速减少,在对流层顶和平流层底达到极小值,平流层里水汽混合比随高度增加。高原上空CH4混合比从140 hPa直至1 hPa随高度递减。在对流层上部和平流层下部H2O和CH4混合比季节差异最明显。高原上空H2O和CH4混合比与同纬度带其它地区相比有不少差异,这种差异在对流层上部和平流层下部更明显。分析还表明:高原上空对流层上部和平流层下部H2O和CH4的分布明显受到高原热力作用引起的垂直运动的影响,高原区域是平流层和对流层交换的活跃区。平流层中上层H2O和CH4的关系很密切,其原因主要是在平流层中上层CH4很容易被氧化成H2O。趋势分析表明,在对流层顶附近,水汽在1993—2004年呈下降趋势,而CH4在1998年以前和2001年以后也呈下降趋势;平流层中层1993—2000年H2O混合比呈增加趋势,CH4呈下降趋势,2000—2004年H2O混合比呈下降趋势,而CH4呈增加趋势。

H_2,CO,CH_4多元爆炸性混合气体支链爆炸阻尼效应

对多元爆炸性混合气体爆炸的阻尼效应 ,进行了比较系统的研究 ,实验表明 :“惰性气体”N2 ,CO2 与水蒸汽对多元混合气体支链爆炸具有一定的抑制作用 ;甲烷与石油液化气对含H2 易爆混合气体支链爆炸具有明显的阻尼效应 .这对指导支链燃烧与支链爆炸的实践 ,关于工业尾气与废气的安全回收 ,有关爆炸性混合气体的置换技术的改进 ,以及工业与矿井混合气体爆炸事故的预防 。

H_2/CH_4流量比对含氢DLC薄膜结构及摩擦学性能的影响

利用等离子体增强化学气相沉积法在Si（100）基体上制备不同H2/CH4流量比下的类金刚石薄膜,采用拉曼光谱、红外光谱、扫描电子显微镜（SEM）、纳米力学性能综合测试仪以及摩擦磨损试验机对薄膜的组织结构、力学以及摩擦学性能进行了分析。结果表明：该条件下制备的薄膜具有典型的类金刚石结构且膜中氢含量较高,薄膜表面光滑,膜层致密且均匀,薄膜的硬度及与基底的附着力均随着H2/CH4流量比的增加而降低。薄膜在大气环境下具有优异的摩擦学性能,在相同的载荷及转速条件下,H2/CH4流量比对薄膜的摩擦因数影响不大。当载荷为5N时,随着转速的增加,摩擦因数降低;而载荷为10N时,摩擦因数约为0.05,转速对其影响较小。薄膜的磨损率在10^-8~10^-7 mm^3/Nm之间变化,且随H2/CH4流量比的增加而增大。

鼓形有机锡氧杂环羧酸簇合物[PhCH_2Sn(O)(O_2CC_4H_3S)]_6·2CH_2Cl_2 和 [PhCH_2Sn(O)(O_2CC_3H_2NO)]_6·2CH_2Cl_2的合成和晶体结构

利用三苄基氧化锡与 2 -噻吩甲酸和 2 -唑甲酸反应 ,合成了六聚体苄基锡氧 2 -噻吩甲酸酯 (1 )和六聚体苄基锡氧 2 -唑甲酸酯 (2 )鼓形簇合物 .通过元素分析、红外光谱和 X射线单晶衍射对其结构进行了表征 .测试结果表明 :化合物 1属三斜晶系 ,空间群 P1 ,a=1 . 2 76 0 (3) nm,b=1 .30 5 6 (3) nm,c=1 .334 3(3) nm,α=1 0 5 .6 5 (3)°,β=96 .2 7(3)°,γ=97.2 0 (3)°,Z=1 ,V=2 .0 997(7) nm3 ,Dc=1 .80 9g/ cm3 ,μ=2 .0 97mm- 1 ,F(0 0 0 ) =1 1 1 6 ,R=0 .0 6 5 1 ,w R=0 .1 2 92 .化合物 2属三斜晶系 ,空间群 P1 ,a=1 .2 2 4 0 (4 ) nm,b=1 .36 73(4 ) nm,c=1 .374 4(4 ) nm,α=1 0 7.76 0 (4 )°,β=98.0 6 9(5 )°,γ=91 .4 80(5 )°,Z=2 ,V=2 .1 6 31 (1 2 ) nm3 ,Dc=3.373g/ cm3 ,μ=3.799mm- 1 ,F (0 0 0 ) =2 1 36 ,R=0 .0 382 ,w R=0 .0 79.它们均为鼓形簇状结构 ,锡原子呈畸变的八面体构型 .化合物 1通过分子间 S… S近距离作用 ,形成一维链状结构 .

CH_4—H_2O体系流体包裹体拉曼光谱定量分析和计算方法

CH4—H2O体系流体包裹体研究对含油气盆地流体分析和成矿流体研究都有重要的意义。本文详细介绍了H2O、CH4和CH4—H2O体系的拉曼光谱特征及分子作用,分析了CH4—H2O体系热力学特征,同时对CH4—H2O体系流体包裹体拉曼光谱定量分析和计算的方法及步骤进行了叙述。利用人工合成流体包裹体建立甲烷浓度与拉曼特征峰面积比值之间的校正曲线是实现CH4—H2O体系流体包裹体定量分析的基础。盐度对包裹体定量分析的影响最为显著,在恒定甲烷浓度下,甲烷与水的拉曼峰面积比值随着盐度增加而减少。对于流体包裹体封闭体系,随温度升高,液相甲烷浓度增大。校正曲线必须包含对温度和盐度的校正。石英主矿物性质和方位对甲烷浓度定量分析的影响可以忽略。实验研究表明,原位拉曼光谱技术是准确获取流体包裹体中甲烷水合物生成条件的一种有效方法。因此,基于拉曼光谱分析和显微测温分析结果,采用热力学模型可以定量计算CH4—H2O体系流体包裹体的相关参数。

H_2气氛下褐煤快速热解过程中CH_4逸出规律的分析

在带有输送煤样的管式反应器上进行了霍林河褐煤加压快速氢解实验,分析了H2对煤/半焦的化学键断裂和对CH4生成规律的影响。在加压快速氢解条件下,CH4产率随着热解温度升高、压力的增大而增大;在50%H2气氛下,操作压力为1.0 M Pa、温度为900℃时,CH4产率为8.08%,达到最大,较N2气氛下的提高了72.5%。H2或H·自由基诱发了芳环的开裂、侧链、脂肪链和醚键的断裂,促进了煤热解。CH4产率的增加主要是由于外部供H的结果;热解温度低于700℃时,H2对煤结构中活性基团的作用促进了煤热解,导致了CH4产率的增加;而热解温度高于700℃后,煤/半焦加氢气化促进了CH4产率的增加。

新型磷酸钒孔道结构化合物(H_3NCH_2CH_2NH_3)_3[(VO)_4(PO_4)_2(HPO_4)_4]的表征及热性能研究

利用五氧化二钒、磷酸作前驱物 ,乙二胺作模板 ,水热法合成了新型孔道结构磷酸盐化合物 (H3 NCH2 CH2 NH3 ) 3[(VO) 4(PO4 ) 2 (HPO4 ) 4]。借助红外光谱 (FT IR)、热分析 (TG DTA)、粉晶X射线衍射 (XRD)及扫描电镜 (SEM)等手段 ,对该化合物晶体在受热条件下的孔容脱除、结构变化及热相变特征等进行了系统研究。从晶体化学角度对其成分、结构及热稳定性之间的关系进行了探讨。指出应通过优化模板、元素替代等方法减弱模板分子与无机骨架间的键联强度及改善基本结构骨架的牢固性 。

[ZnN(CH_2CH_2NH_2)_2(CH_2CH_2N=CHC_6H_4O)]·Pic的合成与晶体结构

在不加任何碱的条件下,三[2-(亚水杨基胺)乙基]胺与苦味酸锌[Zn(Pic)2 6H2O]在乙醇中反应,得到了较为少见的多胺单缩合西夫碱配体的配合物[ZnN(CH2CH2NH2)2(CH2CH2N=CH-C6H4O)] Pic。化学式为C19H23N7O8Zn,Mr=542.81,晶体属三斜晶系,空间群为P,晶胞参数为a=0.7494(3),b=1.1917(5),c=1.3142(6)nm,a=78.111(7),b=79.093(7),g=78.577(7),V=1.1121(8)nm3,Dc=1.621g/cm3,m(MoKa)=1.167mm-1,Z=2,F(000)=560,在1.60<q<25.03悍段谝陨璺绞绞盏蕉懒⒀苌涞?631个,其中I>2s(I)的可观测点为2433个,最终偏离因子R=0.0555,wR=0.1139。配合物中Zn(II)与配体的4个N原子和1个O原子配位形成变形的三角双锥结构,桥头N和O为锥顶,4个配位N中桥头N与金属离子的配位作用最弱。晶体通过p-p堆积和分子内、分子间的氢键作用形成二维层状超分子结构。

Vapor-Liquid Equilibrium Simulation of Binary and Ternary Mixtures of CH_4,C_2H_4 and iso-C_4H_(10)

The vapor-liquid equilibrium(VLE) properties for the binary and ternary mixtures of CH4,C2H4 and isoC4H10 are of great importance in the recovery of ethylene from mixture containing CH4 and C2H4 with iso-C4H10 as solvent.Hence,Gibbs ensemble Monte Carlo(GEMC) simulations were used to estimate vapor-liquid equilibrium for the binary and ternary mixtures of CH4,C2H4 and iso-C4H10 with the united atom potential NERD model.The selected simulation conditions are based on the experiment in the literature.The results of this work were shown to be in satisfactory agreement with available experimental data and predictions of Peng-Robinson equation of state.The structure of simulated liquid phase is also characterized by radial distribution function(RDF),which contributes to further understanding of the VLE curve of these systems.RDF is not sensitive to the pressure and temperature range.With the increase of pressure or the decrease of temperature,the molecules tend to gather together.

新型鼓状有机锡氧杂环羧酸簇合物[PhCH_2Sn(O)(O_2CC_4H_4N)]_6·2CH_2Cl_2的合成和晶体结构

利用三苄基氧化锡与 2 吡咯甲酸反应 ,合成六聚体一苄基锡氧 2 吡咯甲酸酯簇合物 .通过元素分析、红外光谱、核磁共振氢谱和X射线单晶衍射对其结构进行了表征 .X射线单晶衍射测试结果表明 :化合物为三斜晶系 ,空间群P 1,a =1 2 64 4( 3 )nm ,b =1 7416( 4 )nm ,c =1 92 85 ( 4 )nm ,α =90 0 2 1( 4 )° ,β =94 5 85 ( 4 )° ,γ =90 0 2 1( 4 )° ,Z =2 ,V =4 2 3 3 0( 16)nm3 ,Dc=1 715g/cm3 ,μ =1 93 6mm-1,F( 0 0 0 ) =2 13 6,R =0 0 5 2 7,wR =0 0 70 8.该化合物为鼓型簇状结构 ,锡原子为畸变的八面体构型 .

水热法制备Ni/Zr_(0.4)Ce_(0.6)O_2-Al_2O_3催化剂上CH_4-CO_2重整反应研究:NiO含量的影响

采用水热合成法制备不同NiO含量的Ni Zr0 4 Ce0 6 O2 Al2 O3催化剂 ,使用X射线衍射 (XRD)和H2 的程序升温还原 (H2 TPR)对样品进行表征 ,研究了NiO的含量对催化剂结构和CH4 CO2 重整性能的影响。结构表征表明 ,少量Ni组分能在催化剂表面分散并进入CeO2 ZrO2 固熔体晶格间隙而被固熔体包裹 ,并使固熔体晶粒变小 ,促进了固熔体的低温还原 ,而过量的NiO暴露在外生成NiO颗粒。活性测试结果表明 ,NiO含量少的样品活性随反应进行有较高的增长。选择适当空速 ,能使CH4 CO2 以 1∶1反应。

一种新型杂化单晶[Ga_3(PO_4)_3F_2]H_3O·(H_3NCH_2CH_2)_2NH_2的合成与结构表征

A novel three dimensional fluorinated gallium phosphate has been hydrothermally synthesized by using diethylenetriamine as an organic structure directing agent. X ray single crystal structure analysis indicates this compound crystallizes in the orthorhombic space group Pbca, a =1.605 6(7) nm, b = 1 011 4 (4) nm, c =1.854 6(5) nm, V =3.011 6(19) nm 3, Z =4. The three dimensional framework based on linkage of corner sharing polyhedron PO 4, GaO 4F and GaO 4F 2 delimit ten ring channels along b axis in which the triply protonated amines are located serving as charge compensating guests and supporters.

Growth of Mixed Rare Earth Tartrate Crystals (Y_(1-x)Sm_x)_2(C_4H_4O_6)_3·zH_2O from Silica Gels

Experiments performed on the grwth of mixed crystals of rare earth tartrates (Y1-xSmx)2 (C4H4O6)3.zH2O (0≤x≤1) from silica gels at 35~40℃ and 25~30℃ employing single-diffusion technique. are discussed. The crystals maintain spherulitic morphology, irrespective of the value of x, concentration of upper and lower reactants, gel pH, gel age and gel temperature. Formation Of Liesegang rings in this system is a temperature dependent phenomenon. It is shown that with the increase of the value of x the system passes from Liesegangring phenomenon to singlezone phenomenon. Operative mechanism of crystallization in the higher (35~40℃) and lower temperature ranges (25~30℃) is explained. Seeded growth experiments indicate the possibility of increasing the size of the spherulites in the gel medium

天然气集输站场CH_4及H_2S泄漏检测技术研究

可调谐半导体激光吸收光谱技术是一种新型的气体检测方法,其技术关键是利用半导体激光器的窄线宽和可调谐等特性,结合长光程吸收池技术、波长调制技术,并辅以噪声压缩技术,对CH4、H2S分子的吸收线进行测量,从而实现对CH4、H2S气体泄漏的监测和报警。装置具有灵敏度高、选择性好、精度高、响应速度快和远距离遥测等优点。

一维链状高价锰配合物[Mn_2(C_7H_4O_3)_4(CH_3OH)_2]·4H_2O_2CH_3OH的合成与结构

合成了一维链状高价锰配合物[Mn2(C7H4O3)4(CH3OH)2]4H2O2CH3OH,并对其进行了IR、X-射线衍射、UV-Vis和TG-DSC等表征。单晶衍射结果表明,该配合物晶体属三斜晶型,空间群P?晶胞参数a=7.653(5),b=10.486(7),c=12.943(8),=103.24(1),?=104.55(1),?=110.11(1),V=885.4(9)3,Z=1。UV-Vis光谱在547nm有一个吸收峰,相应于Mn(Ⅳ)的d-d电子跃迁光谱。

FeCH2＋H2→Fe＋CH4反应机理的密度泛函理论研究

采用密度泛函理论(DFT)中的UB3LYP方法在6-311+G(2d,2p)水平上研究了五重态和三重态的FeCH2与H2反应的机理,在UB3LYP结构优化的基础上,用耦合簇理论方法UCCSD(T)在相同水平下对各驻点进行了单点能校正.结果表明,该反应在三重态和五重态上的势能面非常相似,存在两个过渡态(TS1、TS2)和两个中间体(M1、M2).反应的第一步是产生分子复合物(H2)FeCH2,其能量分别比反应物低16.6(五重态)和20.3kJ/mol(三重态);第二步是H2的加成形成HFeCH3中间体,第三步是CH4的消除反应.其中CH4的消除为整个反应的速控步骤.H-H键的活化在五重态上是不可逆的,反应将最终形成五重态产物,整个反应可放出能量300.6kJ/mol.