Replacement of methane from quartz sand-bearing hydrate with carbon dioxide-in-water emulsion

The replacement of CH4 from its hydrate in quartz sand with 90:10, 70:30, and 50:50 (W-CO2:W-H2O) carbon dioxide-in-water (C/W) emulsions and liquid CO2 has been performed in a cell with size of empty set 36 x 200 mm. The above emulsions were formed in a new emulsifier, in which the temperature and pressure were 285.2 K and 30 MPa, respectively, and the emulsions were stable for 7-12 h. The results of replacing showed that 13.1-27.1%, 14.1-25.5%, and 14.6-24.3% of CH4 had been displaced from its hydrate with the above emulsions after 24-96 It of replacement, corresponding to about 1.5 times the CH4 replaced with high-pressure liquid CO2. The results also showed that the replacement rate of CH4 with the above emulsions and liquid CO2 decreased from 0.543, 0.587, 0.608, and 0.348 1/h to 0.083, 0.077, 0.069, and 0.063 1/h with the replacement time increased from 24 to 96 h. It has been indicated by this study that the use of CO2 emulsions is advantageous compared to the use of liquid CO2 in replacing CH4 from its hydrate.

有机电磷光器件的研究

自1987年C.W.Tang等人首次报道以Alq_3为发光材料的多层结构有机电致发光器件以来，由于其简单工艺、低成本、主动发光、快速响应以及大面积和柔性可弯曲显示等特点，使其在未来的平板显示领域显示了诱人的应用前景，其研究倍受关注。近些年来，有机发光二极管己经开始商品化。其中，三重态电磷光有机发光材料以其在效率，亮度等方面的优秀性能表现，成为了该领域重要的研究课题。在众多的电磷光材料中，重金属铱的配合物的很多优点引起了广泛的研究。铱配合物电磷光不仅具备了磷光材料理论上可能达到了100％内量子效率的优势，还以其独特的金属一配体电荷跃迁发光性质实现了可见光范围内的全色发光。本论文主要研究了有机电磷光铱配合物的电致发光性能，从不同分子结构铱配合物在不同掺杂浓度下的优化、器件结构设计、母体材料选择以及电磷光发光器件的瞬态特性等方面进行了详细研究，开发出了高效率纯红光有机电磷光发光器件，实现了高效率单层电磷光聚合物发光二极管，用稀土配合物做电磷光掺杂的母体在一定程度上解决了电磷光器件在高电流密度下快速退化问题，对有机电磷光器件的三重态一三重态湮灭和激子衰减动力学过程有了初步认识。（1）研究了几种新型红光铱配合物的电致发光性能：①开发出了以毗嗦为配体的铱配合物，发现其发光光谱（光致和电致）均比哇琳为配体的铱配合物有大幅度的红移，如此制备出了主峰在677nm，色坐标为（0.71，0.28）的深红色有机电磷光器件，器件的外量子效率达到了5.5％以上；②比较了以嗯哇和噬哇为配体的配合物的电致发光性能，发现在结构相近的情况下，电负性越强的原子导致发射光谱蓝移，而在配体上引入高电负性O原子在一定程度上提高了器件的电致发光性能。（2）在高效有机发光器件的制备和结构优化等方面开展的一系列工作得到了如下结论：①不同取代基团配体铱配合物依赖于掺杂浓度，通过优化器件可以获得最好的电致发光性能。②用旋涂方法，通过对电子和空穴注入和传输的调控制备出了高效率单层有机电磷光发光器件，最大发光效率达到了25.2cd／A，由于减少了电子和空穴在磷光分子的直接俘获，避免了空间电荷积累引起的空间电场问题，使器件的电致发光性能得到了显著地提高。③研究了用稀土试络合物作为主体材料，掺杂一种铱配合物的电磷光有机发光二极管的电致发光性能，发现在较高的电流密度下，器件的电致发光效率仍然保持较好的稳定性，有效地降低了三重态一三重态湮灭引起的退化问题。（3）我们用瞬态电致发光方法详细研究了电磷光有机发光器件的三重态一三重态湮灭和激子衰减动力学过程，确定了不同取代基团苯基噬哇铱配合物的三重态激子的寿命τ、三重态一三重态湮灭常数K和饱和电流以及它们与器件电致发光效率的关系，这方面的研究对澄清有机发光器件的工作原理和退化机制，进一步改善器件性能具有重要意义。

Resonant Raman Scattering and Photoluminescence Emissions from Above Bandgap Levels in Dilute GaAsN Alloy

The transitions of E0 ,E0 ＋A0, and E＋ in dilute GaAs（1-x） Nx alloys with x = 0.10% ,0.22% ,0.36% ,and 0.62% are observed by micro-photoluminescence. Resonant Raman scattering results further confirm that they are from the intrinsic emissions in the studied dilute GaAsN alloys rather than some localized exciton emissions in the GaAsN alloys. The results show that the nitrogen-induced E E＋ and E0 ＋ A0 transitions in GaAsN alloys intersect at a nitrogen content of about 0.16%. It is demonstrated that a small amount of isoelectronic doping combined with micro-photoluminescence allows direct observation of above band gap transitions that are not usually accessible in photoluminescence.

地带性多年冻土区小流域水文状况对水热季节变化的响应

大兴安岭北部是我国唯一一片地带性连续多年冻土分布区，也是欧亚大陆地带性多年冻土分布区的南缘，因此对气候变化的响应十分敏感。全球变暖必然会影响到冻土土壤水分状态的变化，从而对冻土区的流域水文状况产生影响；小流域是区域研究的主要对象，冻土活动层变化的最直接后果就是引起流域内水文状况发生变化。本研究利用DEM数据划分小流域，在划分出的小流域的基础上，探讨了影响流域流量变化的几个因子，包括降水、蒸散(Evapotranspiration, ET)和土壤持水，初步简化了流域水量平衡方程，可为进一步研究提供基础。主要包括以下方面的内容： a)平均温度的升高必然会影响到冻土土壤水分状态的变化，从而导致区域小流域水文状况随之变化； b)融深与海拔高度存在一定的相关关系，融深随海拔的升高而增加；土壤水分随海拔变化的规律并不明显。年内降水主要集中在每年的5月份到10月份；11月份和12月份降水一般比春季的多，这两个月份气温很低，降水形式主要是雪。不同地点不同海拔下冻土活动层土壤水分含量变化很大，这和当地的环境条件有关，如地表覆被、土壤类型、坡度、坡向等。 c)参考植被蒸散呈明显的周期性波动规律。每年同期蒸散大致维持在同一水平上。从年初到年中，流域内蒸散呈不断增加的趋势。但是变化规律又稍有不同，每年大致从1月份到4月份，蒸散随时间变化很快，几乎呈线性增加。但是从4月中旬开始，到下半年的9月中旬，ET0呈震荡变化趋势。4月中旬开始，蒸散开始震荡增加，到7月份左右达到最大，然后开始震荡降低，大约到9月中旬或10月初开始转为近似线性减少趋势。 d)土壤水分含量的变化ΔW���以表示为下式：ΔW=R-(0.260Rn-0.036N) Kc+c���其中，ΔW���土壤水分含量的变化；R流域出口处流量；Rn为太阳净辐射；N为白昼长度；Kc���被系数；c���常数。 上述研究结果可以为进一步分析年内冻土湿地水分状况对温度变化的响应提供基础，也可为气候变化条件下冻土湿地水文过程的响应研究提供参考。

Characteristics of indoor/outdoor PM2.5 and elemental components in generic urban；roadside and industrial plant areas of Guangzhou City；China

IEECAS SKLLQG

Distribution and mode of occurrence of As；Hg and Se and sulfur in coal Seam 3 of the Shanxi Formation,Yanzhou Coalfield；China

IEECAS SKLLQG

Selective hydrogenation of citral catalyzed with palladium nanoparticles in CO2-in-water emulsion

CO2-in-Water (C/W) emulsion was formed by using a nonionic surfactant of poly (ethylene oxide)-poly (propylene oxide)-poly (ethylene oxide) (P123), and palladium nanoparticles were synthesized in situ in the present work. The catalytic performance of Pd nanoparticles in the C/W emulsion has been discussed for a selective hydrogenation of citral. Much higher activity with a turnover frequency (TOF) of 6313 h(-1) has been obtained in this unique C/W emulsion compared to that in the W/C microemulsion (TOF, 23 h(-1)), since the reaction was taking place not only in the surfactant shell but also on the inner surface of the CO2 core in the C/W emulsion. Moreover, citronellal was obtained with a higher selectivity for that it was extracted to a supercritical carbon dioxide (scCO(2)) phase as formed and thus its further hydrogenation was prohibited. The Pd nanoparticles could be recycled several times and still retain the same selectivity, but it showed a little aggregation leading to a slight decrease in conversion.

Microstructure analysis of nylon 66 by WAXD and SAXS

The analysis of the small angle X-ray scattering (SAXS) data was based upon particle characteristic function, one-dimensional electron-density correlation function and particle distribution function. The microstructure of nylon 66 with different degrees of crystallinity was studied by means of X-ray scattering method. The radius of gyration R-g, the Porod radius R-p, the thickness of crystalline region L-c the thickness of non-crystalline region L-n, the thickness of interphase region d(tr), the long period L, the semiaxises of particles (a, a, b), the distribution of the particle sizes and the scattering invariant were calculated. The results indicate that there was a significant interphase region between the crystalline region and the non-crystalline region. and its content (W-t,W-x) should not be neglected in comparison with that of crystalline region W-c,W-x. The morphology of nylon 66 prepared by isothermal crystallization at a high temperature was mainly a lamellar structure, while the spherical crystals dominated in the quenched sample. The size of the particles in the quenched sample was smaller than that of those in the isothermally crystallized sample. and the distribution of the particle sizes in the isothermally crystallized sample was wider.

Influence of annealing on structure of Nylon 11

Differential scanning calorimeter (DSC), wide-angle X-ray diffraction (WAXD), small-angle X-ray scattering (SAXS), and density techniques have been used to investigate the structural parameters of the solid state of Nylon 11 annealed at different temperatures. The equilibrium heat of fusion Delta H-m(0) and equilibrium melting temperature T-m(0) were estimated to be 189.05 J g(-1) and 202.85 degrees C respectively by using the Hoffman-Weeks approach. The degree of crystallinity (W-c,W-x) ranged approximately 24-42% was calculated by WAXD and compared with those by calorimetry (W-c,W-h) and density (W-c,W-d) measurements. The radius of gyration R-g, crystalline thickness L-c, noncrystalline thickness L-a, long period L, semiaxes of the particles (a, b), electron-density difference between the crystalline and noncrystalline regions eta(c) - eta(a), and the invariant Q increased with increasing annealing temperature. The analysis of the SAXS data was based upon the particle characteristic function and the one-dimensional electron-density correlation function. An interphase region existed between the crystalline and noncrystalline region with a clear dimension of about 2 nm for semicrystalline Nylon 11. Instead of the traditional two-phase model, a three-phase model has been proposed to explain these results by means of SAXS.

稀土配合物的光致和电致发光性能的研究

自从C.W.Tang报导了高效、高亮度的双层结构有机薄膜电致发光(OEL)器件以来,由于其驱动电压低、可做成大面积及制作工艺简单等优点,使其在平板显示和显像领域具有巨大应用潜力而成为研究热点。但以有机小分子和聚合物做发光层的有机电致发光器件的发射光谱谱带较宽,色纯度不好,不利于显示和显像。1991年,J.Kido等人以稀土配合物Tb(acac)_3(acac:乙酰丙

Influence of interface on radiation effects of crystalline polymer - radiation effects on polyamide-1010 containing BMI

Aimed at saving the radiation dose required to crosslinking the polyamid-1010, BMI/PA1010 systems containing different amounts of difunctional crosslinking agent N,N'-bis-maleimide-4,4'-biphenyl methane (BMI) were prepared and the structure changes at the crystallographic and supermolecular levels before and after irradiation were studied by using WAXD, SAXS, and DSC techniques. It was found that by incorporation of BMI the microcrystal size L-100 is lowered due to the formation of hydrogen bond between the carbonyl oxygen of BMI and the amide hydrogen of PA1010 in the hydrogen bonded plane, and the overall crystallinity W-c is also decreased. The presence of BMI causes the crystal lamella thickness d(c) to decrease and greatly thickens the transition zone d(tr) between the crystalline and amorphous regions. As for the irradiated specimen, the maximum increments in the L-100 and W-c against dose curves decrease with BMI content, and the interception point D-i, at which the L-100 and W-c curves intercept their respective horizontal line of L-100/L-100(0) and W-c/W-c(0)=1, shift to lower dose with an increase in BMI concentration. In addition. the mechanism of the radiation chemical reactions in the three different phases under the action of BMI are discussed with special focus on the interface region. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.