Thermally induced evolution of phase transformations in gas hydrate sediment

Thermally induced evolution of phase transformations is a basic physical-chemical process in the dissociation of gas hydrate in sediment (GHS). Heat transfer leads to the weakening of the bed soil and the simultaneous establishment of a time varying stress field accompanied by seepage of fluids and deformation of the soil. As a consequence, ground failure could occur causing engineering damage or/and environmental disaster. This paper presents a simplified analysis of the thermal process by assuming that thermal conduction can be decoupled from the flow and deformation process. It is further assumed that phase transformations take place instantaneously. Analytical and numerical results are given for several examples of simplified geometry. Experiments using Tetra-hydro-furan hydrate sediments were carried out in our laboratory to check the theory. By comparison, the theoretical, numerical and experimental results on the evolution of dissociation fronts and temperature in the sediment are found to be in good agreement.

我国成功进行重离子束治癌临床试验

<正>中国科学院近代物理研究所与兰州军区兰州总医院、甘肃省肿瘤医院等医疗单位密切合作,成功进行了重离子束浅层治癌临床试验,使我国成为世界上第四个完成重离子束治癌临床试验的国家.

Combined study of gamma p ->eta p and pi(-)p ->eta n in a chiral constituent quark approach

Within a chiral constituent quark model approach, η-meson production on the proton via electromagnetic and hadron probes is studied. With few parameters, the differential cross section and polarized beam asymmetry for γp → ηp and differential cross section for π − p → ηn processes are calculated and successfully compared with the data in the center-of-mass energy range from threshold up to 2 GeV. The five known resonances S11(1535), S11(1650), P13(1720),D13(1520), and F15(1680) are found to be dominant in the reaction mechanisms in both channels. Possible roles played by new resonances are also investigated; and in the photoproduction channel, significant contribution from S11 and D15 resonances, with masses around 1715 and 2090 MeV, respectively, are deduced. For the so-called missing resonances, no evidence is found within the investigated reactions. The helicity amplitudes and decay widths of N ∗ → πN, ηN are also presented and found to be consistent with the Particle Data Group values.

eta-production on the proton via electromagnetic and hadronic probes

The reactions pi(-)p -> eta n and gamma p -> eta p are investigated within a dynamical coupled-channels model of meson production reactions in the nucleon resonance region The meson-baryon channels included are pi N, pi Delta, sigma N, and rho N The direct eta-photoproduction process is studied within a formalism based on a chiral constituent quark model approach, complemented with a one-gluon-exchange mechanism, to take into account the breakdown of the SU(6)circle times O(3) symmetry In the models search, the following known nucleon resonances are embodied S-11(1535), S-11(1650), P-11(1440), P-11(1710), P-13(1720), D-13(1520), D-13(1700), D-15(1675), and F-15(1680). Data for the pi(-)p -> eta n reaction from threshold up to a total center-of-mass energy of W approximate to 2 GeV are satisfactorily reproduced For the photoproduction channel: two additional higher mass known resonances, P-13(1900) and F-15(2000), are also considered However, reproducing the data for gamma p -> eta p requires, within our approach, two new nucleon resonances, for which we extract, mass and width

Study of nucleon resonances in a chiral quark model via eta productions

In this report we investigate eta-meson productions oil the proton via electromagnetic and hadron probes in a chiral quark model approach. The observables, such as, differential cross section and beam asymmetry for the two productions are calculated and compared with the experiment. The five known resonances S-11(1535) S-11(1650); P-13(1720) D-13(1520), and F-15(1680) are found to be dominant in the reaction mech-anisms in both channels. Significant, contribution from a new S-11 resonances are deduced. For the so-called "missing resonances", no evidence is found within the investigated reactions. The partial wave amplitudes for pi(-)p -> eta n are also presented.

eta photoproduction on the proton in a chiral constituent quark approach via a one-gluon-exchange model

A formalism based on a chiral quark model (chi QM) approach complemented with a one-gluon-exchange model, to take into account the breakdown of the SU(6)circle times O(3) symmetry, is presented. The configuration mixing of wave functions for nucleon and resonances are derived. With few adjustable parameters, differential cross-section and polarized-beam asymmetry for the gamma p -> eta p process are calculated and successfully compared with the data in the center-of-mass energy range from threshold to 2 GeV. The known resonances S-11(1535), S-11(1650), P-13(1720), D-13(1520), and F-15(1680), as well as two new S-11 and D-15 resonances, are found to be dominant in the reaction mechanism. Moreover, connections among the scattering amplitudes of the chi QM approach and the helicity amplitudes, as well as decay widths of resonances, are established. Possible contributions from the so-called missing resonances are investigated and found to be negligible.

垂直流人工湿地处理稠油废水的实验研究

采用垂直流人工湿地模拟装置对新疆油田外排含盐稠油废水进行了处理。实验表明:对于进水CODCr为402～406mg/L,盐度5701～5712mg/L,石油类40.62mg/L的含盐稠油废水,该系统的出水指标为CODCr35～38mg/L,盐度1535～1542mg/L,湿地系统对CODCr和盐分的去除率达到91%和73%;当水力停留时间为11d以上,出水石油类<5mg/L,处理后出水CODCr、石油类达到《污水综合排放标准》(GB8978-1996)的一级标准。

应用生态学的现状与展望

应用生态学是迅猛发展的现代生态学的主体 .寻求解决人口、资源、环境等问题是应用生态学发展的主要动力 .经过 4 0年的发展 ,应用生态学已发展成为一个庞大的学科门类 .应用生态学未来的发展应更多地关注受人类影响和管理的生态系统并将人视为生态系统的组成成分 .应用生态学在当前和今后应给予优先重视的研究领域 ,包括生态系统与生物圈的可持续利用、生态系统服务与生态设计、转基因生物的生态学评价、生物入侵生态学、流行病生态学、生态预报、生态过程及其调控等 .在今后若干年内 ,围绕这些领域 ,可能会出现广泛而活跃的研究热潮以及一些新的特点 .

Mineral chemistry and its genetic significance of olivine in Cenozoic basalts from the South China Sea

We dredged lots of Cenozoic basalts from areas covered from the northern sub-slope to the southern sub- slope of the South China Sea. Based on the study on mineral chemistry of clinopyroxenes in these Cenozoic hasalts, this paper indicates that pyroxenes are mostly enstatite and a few of augite, sahlite and Ca-rich pyroxene. Pyroxene microlite has higher content in, Ca, Ti and Fe than pyroxene phenocryst, it may reflect that the evolution trend of host magma of pyroxene is coincidence with that of alkali rock series. The depth of magma chambers which calculated from equilibrium temperatures and pressures between clinopyroxene and melt are as follows, that of magma of tephrite is about 49km, that of magma of trachybasalt is about 25km, and that of magma of basalt is about 15km. Correspondingly, Equilibrium temperatures( K) of three types rocks mentioned above gradually decrease from 1535 1498 to 1429 to 1369. By using discriminant plot which developed from pyroxene and alkali discriminant diagram of host rock, Cenozoic basalt from the South China Sea belongs to intraplate alkali basalt. The results suggest that alkali basalt series in the study area may be the products of continuous evolution of mantle plume, which result from some physical and chemistry process including partial melting and fractional crystallization of mantle plume during the course of its ascent to the surface.

末次冰期以来西赤道太平洋边缘海古气候变化研究

本文所研究的区域是西赤道太平洋的两个边缘海盆-苏禄海和南中国海。这两个边缘盆地具有明显不同的水文特征，南中国海底层水冷（<4 ℃）并且通气较好（溶解氧浓度>1.75ml/l），而苏禄海底层水温暖（>10 ℃）并且含氧量低（溶解氧浓度<1.25ml/l）。这些不同的水文特征导致了不同的沉积环境，同时两个海盆的沉积记录也包含了这些水文条件在不同地质时间上如何变化的历史。笔者分别对南中国海的GGC-6孔（12°09'1''E，118°03'9''，水深2775米）和苏禄海的GGC-29孔（8°17'7''E，118°49'9''N，水深1535米）的浮游和底栖有孔虫动物群进行了系统地分析鉴定和统计，并用转换函数对古温度进行了分析，力求通过有孔虫化石群的面貌和定量古生态分析来反映古气候的变化。通过对浮游有孔虫氧同位素环境效应的分析来探索本区的古气候变化。此外还对沉积物中的有机碳和碳酸钙的含量进行了测试和分析。通过上述工作我们得出以下几点认识：1、氧同位素和古水温记录可分末次冰期和全新世两期，由于岩心的长度所限地质记寻年代较短为24000年左右。2、浮游有孔虫G.Grassaformis的最后出现是苏禄海末次冰期极盛时（～18000B.P）重要的地质界线。3、发现在北欧地区短暂寒冷的仙女木期（Younger dryas）在本区也有发现。这在一定程度上说明了仙女木期存在的全球性。4、本区末次冰期与全新世的夏季表层古水温相差不到2 ℃与CLIMAP（1976）赤道太平洋末次冰期以来古水温度的模拟结果相附。冬季表层水温相差较大为3.5 ℃左右。5、瓷质壳底栖有孔虫的繁盛和翼足类的大量保存是苏禄海冰期时底层暖水的良好指示标志。6、本区有机碳的含量反映了底层水含氧浓度的变化。高有机碳代表低氧浓度，低有机碳代表高氧浓度。南中国海一直受到西北太平洋水体的影响，致使其底层水一直处于充氧状态，只是在冰期最盛时稍有降低。而苏禄海底层水氧浓度较低，尤其是末次冰期极盛时隔绝状态加强，大量的降水使表层海水淡化分层，致使底层水缺氧状态加剧。7、本区做为西赤道太平洋的边缘海，其CaCO_3旋回模式却与太平洋相反，而与大西洋一致，即冰期碳酸钙含量低，全新世冰后期碳酸钙含量高。冰期陆源物质供应的加强和全新世浮游有孔虫生产力的提高是控制本区碳酸钙旋回的主要因素。此外，冰期海水溶解作用的加强是南中国海冰期低CaCO_3含量的另一个重要原因，而苏禄海的碳酸钙沉积受海水溶解作用的影响却很小。8、浮游有孔虫N.dutertrei的大量增加和相对较轻的δ~(18)O值说明冰期最盛时海水表面的盐度较低。末次冰期时东南亚地区东北季风加强西南季风减弱，由于特殊的地理环境使本区在冰期时降水大量增加。

南海新生代碱性玄武岩的特征及其地球动力学意义

南海是西太平洋最大的边缘海之一，位于欧亚板块、印-澳板块以及太平洋板块之间。南海海底扩张停止(15.5Ma, Briais et al., 1993) 后的板内火山作用，影响着中国南部、中南半岛、大洋基底和分裂的微大陆片段的广大地区。对南海新生代玄武岩进行地球化学研究，不仅对于理解南海板内火山作用的深部地幔过程有着重要意义，而且对南海形成演化及含油气盆地形成的深部动力学机制有着深远意义。 南海新生代玄武岩K-Ar/Ar-Ar年龄为3.8-7.9Ma, 表明为晚中新世以来的岩浆活动产物，与周边地区的碱性火山岩在年龄上的一致性。岩石学特征表明，南海新生代玄武岩的矿物组合为橄榄石、单斜辉石、斜长石，与特征的碱性玄武岩的矿物组合一致。由橄榄石所计算的南海底潜在地幔温度(Tp)平均值为1661℃, 暗示南海地区下的地幔可能存在热量异常，为海南地区存在地幔柱的观点提供了证据。单斜辉石富钙、钛，由单斜辉石-熔体平衡温压计计算的岩浆房深度分别为：碱玄岩岩浆房深度约49km（对应压力为1.46～1.48 GPa）；粗面玄武岩岩浆房约25km（对应压力为0.76 GPa）；玄武岩岩浆房约15km（对应压力为0.44GPa）。由碱玄岩→粗面玄武岩→玄武岩，平衡温度(K)依次降低:从1535～1498→1429→1369。由斜长石微晶所计算的岩浆喷出地表的温度为989℃。 主量元素特征表明，岩石类型主要为碱玄岩，有少量的粗面玄武岩和玄武岩，属于碱性系列。微量元素方面，大离子亲石元素(LILE)以及高场强元素（HFSE）特别是Nb、Ta、Ti、Y等元素均呈现富集现象，Yb、Sc、Sr以及K、U、Th等生热元素相对亏损，微量元素及稀土元素分布岩石类似板内OIB微量元素的全球平均值。同位素地球化学研究表明，源区存在两个混合端员并具Dupal Pb异常：一个为DMM，位于软流圈或岩石圈地幔中；另一个为EM2源区，可能来自位于核-幔边界处的海南地幔柱而非大陆底岩石圈地幔。研究表明，南半球Dupal异常不存在全球范围内的地区专属性，本区存在的Dupal异常与南半球Dupal异常可能不存在联系。在南海新生代玄武岩的成因过程中，海南地幔柱在为岩石圈地幔的部分熔融作用提供所需的热量同时，也在物质上作出了贡献。南海盆新生代碱性玄武岩由不同程度的部分熔融作用，以及岩浆在上升期间或者在高位岩浆房中的橄榄石等矿物分离结晶作用所形成，同时还可能发生了堆晶作用。构造环境判别表明，玄武岩浆在上升到地表过程中几乎未受到地壳混染。 南海新生代玄武岩的地球化学研究表明，在玄武质岩浆的深部地幔演化过程中，海南地幔柱可能起着重要的作用。通过引入海南岛地幔柱这个概念，本文建立了一个新的有关南海形成演化的初步的概念性模型：（1）50-32Ma，印度洋板块-欧亚板块碰撞及其所导致的太平洋板块后退的综合效应为南海地区提供了一个伸展环境，此伸展环境为地幔柱物质的上升提供了通道；（2）32-21Ma，当地幔柱柱头到达软流圈时, 通过侧向物质流开始同扩张中心发生相互作用，促进了南海的扩张，并在26-24Ma期间发生了洋脊重新就位事件，使扩张中心从原来的18°N附近(即现今西北海盆的中心)调整到15.5°N附近（即现今的东部亚盆）；（3）21-15.5Ma, 随着地幔柱效应的逐渐增强，热点-洋脊相互作用越来越强烈，在大约21Ma发生了洋脊的再次重新就位事件，诱发了西南海盆的扩张；（4）15.5-现在，由于印澳板块前缘与巽他大陆碰撞，使得南海大约在15.5Ma停止扩张,并沿着南沙海槽及吕宋海沟向菲律宾岛弧及巴拉望地块之下俯冲，而南海热点继续活动，在地表处直到第四纪还有碱性玄武岩喷出。

印染废水治理研究现状

本文综述了印染废水水质及特点，染料的分类和发色机理。评述了目前印染废水治理研究中的各种物理、化学和生物方法应用现状、优点和存在的问题，及其对脱色效果的影响机理。