Partial oxidation reforming of biomass fuel gas over nickel-based monolithic catalyst with naphthalene as model compound

With naphthalene as biomass tar model compound, partial oxidation reforming (with addition of O-2) and dry reforming of biomass fuel gas were investigated over nickel-based monoliths at the same conditions. The results showed that both processes had excellent performance in upgrading biomass raw fuel gas. Above 99% of naphthalene was converted into synthesis gases (H-2+CO). About 2.8 wt% of coke deposition was detected on the catalyst surface for dry reforming process at 750 degrees C during 108 h lifetime test. However, no Coke deposition was detected for partial oxidation reforming process, which indicated that addition of O-2 can effectively prohibit the coke formation. O-2 Can also increase the CH4 conversion and H-2/CO ratio of the producer gas. The average conversion of CH4 in dry and partial oxidation reforming process was 92% and 95%, respectively. The average H-2/CO ratio increased from 0.95 to 1.1 with the addition of O-2, which was suitable to be used as synthesis gas for dimethyl ether (DME) synthesis.

Vacuum pyrolysis of waste tires with basic additives

Granules of waste tires were pyrolyzed tinder vacuum (3.5-10 kPa) conditions, and the effects of temperature and basic additives (Na2CO3, NaOH) on the properties of pyrolysis were thoroughly investigated. It was obvious that with or without basic additives, pyrolysis oil yield increased gradually to a maximum and subsequently decreased with a temperature increase from 450 degrees C to 600 degrees C, irrespective of the addition of basic additives to the reactor. The addition of NaOH facilitated pyrolysis dramatically, as a maximal pyrolysis oil yield of about 48 wt% was achieved at 550 degrees C without the addition of basic additives, while a maximal pyrolysis oil yield of about 50 wt% was achieved at 480 degrees C by adding 3 wt% (w/w, powder/waste tire granules) of NaOH powder. The composition analysis of pyrolytic naphtha (i.b.p. (initial boiling point) similar to 205 degrees C) distilled from pyrolysis oil showed that more dl-limonene was obtained with basic additives and the maximal content of dl-limonene in pyrolysis oil was 12.39 wt% which is a valuable and widely-used fine chemical. However, no improvement in pyrolysis was observed with Na2CO3 addition. Pyrolysis gas was mainly composed of H-2, CO, CH4, CO2, C2H4 and C2H6. Pyrolytic char had a surface area comparable to commercial carbon black, but its proportion of ash (above 11.5 wt%) was much higher.

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.

Use of electrical resistance to detect the formation and decomposition of methane hydrate

The changes of electrical resistance (R) were studied experimentally in the process of CH4 hydrate formation and decomposition, using temperature and pressure as the auxiliary detecting methods simultaneously. The experiment results show that R increases with hydrate formation and decreases with hydrate decompositon. R is more sensitive to hydrate formation and decompositon than temperature or pressure, which indicates that the detection of R will be an effective means for detecting natural gas hydrate (NGH) quantitatively.

Determination of appropriate condition on replacing methane from hydrate with carbon dioxide

This paper is intended to determine the appropriate conditions for replacing CH4 from NGH with CO2. By analyzing the hydration equilibrium graphs and geotherms, the HSZs of NGH and CO2 hydrate, both in permafrost and under deep sea, were determined. Based on the above analysis and experimental results, it is found that to replace CH4 from NGH with gaseous CO2, the appropriate experimental condition should be in the area surrounded by four curves: the geotherm, (H-V)(CO2), (L-V)(CO2) and (H-V)(CH4), and to replace CH4 from NGH with liquid CO2, the condition should be in the area surrounded by three curves: (L-V)(CO2), (H-L)(CO2) and (H-V)CH4. For conditions in other areas, either CO2 can not form a hydrate or CH4 can release little from its hydrate, which are not desirable results.

Clathrate Dissociation Conditions for Methane + Tetra-n-butyl Ammonium Bromide (TBAB) + Water

Hydrate equilibrium data of the CH4 + tetra-n-butyl ammonium bromide (TBAB) + water have been measured by using the isothermal pressure search method for four components of TBAB aqueous solutions. The three-phase equilibrium lines obtained in the present study are shifted to the low-temperature or high-pressure side from that of the stoichiometric TBAB solution. Moreover, methane uptake into semi-clathrates is confirmed by a shift in the clathrate regions when methane is present. The experiments are carried out in the pressure range of (0.5 to 11) MPa and in the temperature range of (281.15 to 295.15) K.

Ti-V-Cr固溶体储氢合金的结构及电化学性能研究

本论文首先研究了Ni、Zr分别对Ti-V－Cr固溶体储氢合金中Cr和Ti部分取代的影响，得到了性能良好的Ti0．17Zr0．08V0．35Cr0．10Ni030基质合金。在此基础上进一步研究了入甄、B、Fe、Co、Al元素的添加或取代对基质合金的结构及电化学性能的影响。采用XRD、ICP、SEM一EDX、XPS、EIS、线性极化和阳极极化等表征手段对Ti一V－Cr固溶体储氢合金的结构及电化学性能进行分析和表征，主要结果如下：①Ti一V－Cr合金自身在碱性电解液中几乎无电化学活性。当用Ni部分取代Cr后，合金中出现具有电化学活性的第二相，其电化学性能得到有效地改善和提高。②Ti0.25-xZr_xV0.35Cr0.1Ni0.3（x＝0．05-0．15）合金主要是由bcc相和c14Laves相组成。随Zr含量从0．05增加到0．08，合金电极的放电容量和倍率放电能力增加；当x继续从0．08增加到0．15时，其变化较小。合金电极的电荷转移电阻随x增加而降低，当x在0．08到0．15之间变化时，电荷转移电阻变化也比较小。表明电荷转移电阻的大小与合金的电化学性能密切相关。③经过50次充、放电循环后，Tio．17zr"sV时scrol0Ni03。合金电极在303K和313K的放电容量能保持在90％以上；在70℃时的放电容量仍能达到275mA扮g。根据不同温度时的交换电流密度，计算了Ti。，17Zr008V时SCr川0Ni030合金电极表面电化学反应的表观活化能，其值约为50kJ／mol。④通过Nln、B、Fe、C。、AI对Tio．17zroosvo35Crol0Nio3。合金基质的添加与取代的研究，得到了具有高容量的储氢合金。其中Tio．17Zr008Vo35Cro．10Ni020Mnol。合金室温最高放电容量达到390n1A扮g；在253一343K的温度范围内，Tiol7Zr08V035Cr0JONioz5Mnoos合金具有高的放电容量，其容量在167一298mA树g之间变化，但是这些合金的稳定性有待进一步的提高。⑤合金充、放电过程中，晶格的扭曲和膨胀、Zr和V的溶解使得合金结构发生变化；合金的严重粉化及表面致密氧化膜的形成，是导致Ti一V－Cr合金电化学性能的衰减的主要原因。

Ce-基催化剂上CH_4低温催化燃烧的研究

Ce-基催化剂在汽车尾气净化，工业废气处理，烃类重整，烃类选择加氢等方面均有广泛的应用。近几十年来关于如何制备高活性、高稳定性的非贵金属复合氧化物催化剂一直是催化研究的重要课题之一。Ce-基催化剂主要都是通过其它金属氧化物M掺杂到CeO_2中形成Ce_(1-x)M_xO（M为掺杂物）固溶体。本文选用CeO_2作为主要研究对象，用柠檬酸法有目的的引入化学特性、离子半径不同的另一组分，用x值表示各元素间的化学计量比，优化催化剂的组成、结构，来调节所合成固溶体氧化物的物理化学性质。分别以碱土金属Ca、稀土金属La以及过渡金属Ni和Mn为掺杂物制备出含其它不同离子的Ce-基催化剂；将具有较高活性的Ni_(0.7)Ce_(0.3)O负载在ZrO_2上，以CH_4燃烧为模型反应，考察催化剂活性和氧化还原性的关系。1．Ce-Ca-La-O体系单独Ca或La分别加入到CeO_2中后催化剂的活性比单独的CeO_2的活性要高出很多，完全转化温度要下降近100℃，而且它们的H_2-TPR实验也证实了其氧化还原能力有很大的提高。将Ca和La同时引入到CeO_2的复合氧化物Ce-La-Ca-O材料，其活性比无La的Ce-Ca-O的活性没有明显的提高，而且反而要比Ce-La-O的活性低，且其HZ一TPR实验也显示出和复合氧化物Ce-Ca-O的轮廓一样。2．Ce-Ni-Mn-O体系对NiO、MnO_x、CeO_2三种金属氧化物，在优化两种金属氧化物最佳配比（组成）后，在复合氧化物中掺杂第三种金属氧化物以考察第三种金属对其甲烷燃烧活性的影响。（l）CeO_2-MnO_x体系中，在Ce_(0.8)Mn_(0.2)O掺杂NiO后，发现当Ni的摩尔量为-10％时，活性提高幅度的很大，完全燃烧的温度下降了近50℃，可在550℃将CH_4完全氧化到CO_2。（2）CeO_2-NiO体系中，Ce_(0.3)Ni_(0.7)O可在530℃将CH_4完全氧化到CO_2。向其中掺杂Mn后，复合氧化物的活性反而下降，要在550oC才能将CH4完全氧化到C02。这可能是阴离子缺陷减少所致。（3）NIO一Mnox体系中，Nio，IMn090掺杂Ce后，催化活性有大幅度提高，特别是Nio．ICeyMno90（0．3三y生0．8）中催化剂的活性更高，可在530oC体系中，其中y＝0．5时更突出。3．Ni-Ce-O／ZrOZ体系（1）Ni1-x一Cex一O体系中，独立的CeOZ相促进了NIO的还原和表面积增加。（2）少量的CeOZ的掺杂明显改善了NIO对cH4完全氧化反应的活性。继续增加Ce的量催化活性弱有增加，然后下降。在Ce的掺杂量为30％时，即Nio7Ceo3O，催化活性最佳，此时甲烷完全转化的温度为530oC。（3）催化剂Ni07Ceo3O具有很好的稳定性，900oC下焙烧，还能在540oC将CH4完全氧化到COZ。（4）催化剂Pd／Ni07Ceo30的催化活性与Pd／A12O3的活性相当。（5）催化剂Ni07Ce03O负载在不同的载体上，发现ZrOZ作载体效果最佳，其次为5102，这可能是ZrOZ、5102对NIO、CeOZ相对惰性有关；而MgO、A1203虽表面积较大，但作为载体效果却不好，可能其易与NIO、CeOZ发生反应有关。（6）Nio7Ceo3O负载在ZrOZ上，提高了表面积同时促进了Nio7Ceo3O还原性，以负载量为50％时活性最好。结构分析发现有两个新相生成，Ni4Zro和CeZO3。（7）通过对比发现Nio7Ceo3O（50％）／ZrOZ体系高活性除了ZrOZ作为载体提高表面积外，Zr02和Ce在这里还起到助催化剂的作用。4．还探讨了Pr掺杂到CeO2，以及YSZ作为载体负载过渡金属氧化物在甲烷催化燃烧反应种的作用。

INVESTIGATION OF THE GROWN DIAMOND (100) SURFACE USING HIGH-RESOLUTION ELECTRON-ENERGY LOSS SPECTROSCOPY

The diamond (100) facets deposited at initial 1.0% CH4 have been investigated using high resolution electron energy loss spectroscopy (HREELS). The diamond (100) facets grown at 800-degrees-C are terminated by CH2 radicals, and there is no detectable frequency shift compared with the characteristic frequencies of molecular subgroup CH2. Beside the CH2 vibration loss, CH bend loss (at 140 meV) of locally monohydrogenated dimer is detected for the diamond (100) facets grown at 1000-degrees-C. Dosing the (100) facets grown at 800-degrees-C with atomic hydrogen at 1*10(-6) mbar, the loss peak at 140 meV appears. It is suggested that there are enough separately vacant sites and uniformly dispersed monohydrogenated dimers on (100) facets. This structure relaxes the steric repulsion between the adjacent hydrogen atoms during the diamond (100) surface growth.

掺铒a-Si_xC_(1-x)-H薄膜的发光特性

用等离子体增强化学气相沉积(PECVD) 的方法,以固定的氢气(H2)流量和不同的硅烷(SiH4)和甲烷(CH4)流量比沉积了一系列的氢化非晶SiC(a-SixC1-x-H)膜.用这种宽带隙的a-SixC1-x-H材料作为掺铒的基体材料,通过离子注入的方法得到掺铒的a-SixC1-x-H(a-SixC1-x-H:Er)膜.注入以后的样品经过不同温度的退火.用X射线光电子能谱(XPS)、红外吸收光谱(IR)、拉曼散射谱(Raman)等技术研究不同的SiH4/CH4流量比和退火温度对a-SixC1-x-H:Er发光强度的影响.结果表明,高温退火引起了膜中C的分凝,对铒的发光是不利的.通过低温和室温下铒发光强度的比较,表明这种材料具有较弱的温度猝灭效应.

氢稀释对非晶硅碳(a-SiC:H)合金薄膜生长和光学特性的影响

用PECVD方法,以固定的甲烷硅烷气体流量比([CH4]/[SiH4]=1.2)和不同的氢稀释比(RH=[H2]/[CH4+SiH4]=12,22,33,102和135)制备了一系列的氢化非晶硅碳合金(a-SiC:H)薄膜.运用紫外-可见光透射谱(UV-VIS)、红外吸收谱(IR)、Raman谱以及光荧光发射谱(PL)测量研究了氢稀释和高温退火对薄膜生长和光学特性的影响.实验发现氢稀释使薄膜光学带隙展宽(从1.92到2.15 eV).高氢稀释条件下制备的薄膜经过1250℃退火后在室温下观察到可见光发光峰,峰位位于2.1 eV.结合Raman谱分析,认为发光峰源于纳米硅的量子限制效应,纳米硅被Si-C和Si-O限制.

Improved neutron radiation hardness for Si detectors: Application of low resistivity starting material and or manipulation of N-eff by selective filling of radiation-induced traps at low temperatures

Radiation-induced electrical changes in both space charge region (SCR) of Si detectors and bulk material (BM) have been studied for samples of diodes and resistors made on Si materials with different initial resistivities. The space charge sign inversion fluence (Phi(inv)) has been found to increase linearly with the initial doping concentration (the reciprocal of the resistivity), which gives improved radiation hardness to Si detectors fabricated from low resistivity material. The resistivity of the BM, on the other hand, has been observed to increase with the neutron fluence and approach a saturation value in the order of hundreds k Omega cm at high fluences, independent of the initial resistivity and material type. However, the fluence (Phi(s)), at which the resistivity saturation starts, increases with the initial doping concentrations and the value of Phi(s) is in the same order of that of Phi(inv) for all resistivity samples. Improved radiation hardness can also be achieved by the manipulation of the space charge concentration (N-eff) in SCR, by selective filling and/or freezing at cryogenic temperatures the charge state of radiation-induced traps, to values that will give a much smaller full depletion voltage. Models have been proposed to explain the experimental data.

不同水分管理下稻田CH<,4>和N<,2>O的排放及其微生物学过程

大量研究表明，农田水分状况发生变化对CH<,4>排放有重大影响，水稻生长期的晒田处理不仅有利于植株生长而且能增加CH<,4>氧化，减少CH<,4>生成.但近年来注意到有利于控制CH<,4>排放的水分管理措施往往会促进N<,2>O排放，而其机理及对大气净温室效应的影响报道甚少.该文对不同水分管理下CH<,4>和N<,2>O的排放进行了定量分析并对温室效应的贡献进行了估算;同时对二种气体排放的微生物学过程进行了研究，观测了相关微生物菌群数量及田间环境因子的变化，并对不同水分处理期间的土壤理化性质对CH<,4>和N<,2>O排放及微生物数量的影响作了进一步分析，为制定综合控制稻田CH<,4>和N<,2>O的排放措施提供了科学依据.

黑土稻田生长季／休闲期温室气体排放研究

本文以黑土稻田为供试对象，对稻田生长季和休闲期CH4和N2O的排放通量进行了研究。结果表明，黑土稻田生长季CH4的排放总量为2.719／m2，接近中国稻田生长季CH4排放总量变化范围的下限。N2O的排放量很少，只有0.07g／m2，排放主要集中在水稻生长季节中的排水阶段。采用间歇灌溉和施用长效尿素的农田管理方式后，计算综合温室效应发现，间歇灌溉措施和施用长效尿素分别能减少稻田生长季CH4和NZO综合排放量的13 ．3％和4.8％。稻田休闲期CH4的排放量很小，可忽略不计；NZO的排放主要发生在春季土壤融化期，排放量占休闲期NZO排放总量的57.4％。针对大田冻融期获得的结果，设计了室内模拟冻融试验。结果表明，冰冻土壤在融化初期出现NZO的排放高峰，而土壤冰冻初期在短时间内也排放大量的N2O。添加硝态氮的处理在冻土融化时，N2O的排放量显著高于未添加硝态氮处理。冰冻时间越长，则冻融期间的N2O排放量越大。在水稻休闲季节对土壤进行了翻耕并施入稻草处理，结果表明翻耕能减少土壤中N2O的排放，施加稻草则增加N2O的排放；翻耕和施加稻草均能促进大田CO2的排放。针对东北黑土区气温逐年升高的情况，设计了室内模拟试验考察温度升高对黑土稻田土壤淹水期cH；刻卜放的影响。结果表明，温度升高显著促进稻田CH；的排放。

涡动相关法估算森林生产力及与测树学方法的比较

大气中CO2、CH4和其它温室气体浓度升高导致的全球气候变化引起了人们对全球碳循环和碳收支的关注，植被与大气间CO2通量的长期测定能够加深对陆地生态系统在全球碳循环作用的科学理解。本文以我国北方典型的温带植被类型长白山阔叶红松林为研究对象，利用观测塔上的涡动相关系统对长白山阔仆卜红松林进行长期的CO2通量监测，并分析CO2通量的周年动态，估算森林净生态系统生产力；同时基于测树学方法，进行群落调查，根据已有的经验公式，估算森林净生态系统生产力，综合评价长白山阔汗卜红松林碳收支，为森林碳收支的研究提供基础。主要结论有：（1）FSAM模型的分析结果表明，观测塔上40m高度的涡动相关仪器测量的信息中，76％来自于西北至西南方相对均质的阔叶红松原始林，其中footprint最大的源区在塔西南方100m-400m范围内。因此，森林群落调查选择在此区内进行，使得涡动相关法和测树学方法估算的生产力具有可比性。（2）2003-2004年碳通量季节变化趋势基本一致，从年初到4月上旬该森林生态系统保持较弱的正的碳通量（释放CO2），5月开始表现为净的碳吸收，且吸收量迅速增加，到6月达到最大值，然后又逐渐减小；9月末到10月末随着生长季的结束，净生态系统COZ交换（NEE）开始由负转为正，11-12月NEE为正，生态系统以呼吸为主。净生态系统COZ交换的年累计量表明长白山阔叶红松林为明显的碳汇，2003年和2004年净生态系统生产力NEP分别为-217±75gcm-2a-1和-190±85gcm-2a-1，相当于-2.17±0.75tCha-1a-1和-1.90±0.85tCha-1a-1。（3）根据经验公式和材积法得到阔汗卜红松林的生物量在343．9-362．3tha－l之间，应用两种方法得到2003一2004年群落的净初级生产力在10.22-10.40tCha-1a-1之间，净生态系统生产力在2.50±1.12tCha-1a-1-2.68±1.20tCha-1a-1之间。（4）测树学方法与涡动相关法测得的净生态系统生产力略有差异，但在误差有效范围内基本一致。