YBa_2Cu_3O_(7-Y)超导体激光熔凝处理的研究

利用CO_2激光对YBa_2Cu_3O_(7-Y)块材进行熔凝处理后,证明可逆反应式YBa_2Cu_3O_(7-Y)(?)Y_2Cu_2O_5+4BaCuO_2成立,在结构上消除了孔洞等缺陷,使晶粒细化均匀,有序化程度及致密度提高,有效地提高了材料的临界电流密度J_c,从而提出用CO_2激光制备高温超导体YBa_2Cu_3O_(7-y)超导体块材、带材及线材实用化的新工艺.

Development of SSR primers from EST sequences and their application in germplasm identification of Porphyra lines (Rhodophyta)

This paper reports the development of SSR markers from EST data and their utilization in germplasm identification of Porphyra. The publicly available EST (expressed sequence tag) sequences of Porphyra were searched from the Internet (www.kazura.or.jp/en/plant/porphyra/EST/). From a total of 20,779 obtained EST sequences, 391 SSRs (simple sequence repeats) were analysed with SSRIT software (www.gramene.org/db/searches/ssrtool). From those, 48 SSR primer-pairs were designed and tested by commonly used SSR reaction conditions using 22 Porphyra DNA samples as templates. Results showed that 41 SSR primer-pairs gave good amplification patterns. These were used to conduct SSR analyses of genetic diversity and variety identification of the 22 Porphyra lines. A dendrogram and the DNA fingerprints of the Porphyra lines were developed based on the obtained SSR data.

Cultivation of the brown alga Hizikia fusiformis (Harvey) Okamura: enhanced seedling production in tumbled culture

The reuse of holdfasts for regeneration of young seedlings or using wild juvenile plants as the seedling source has played the major role in commercial cultivation of the brown alga Hizikia fusiformis in East Asia over the past 20 years. The possibility of employing zygote-derived germlings for producing seedlings has been discussed in the literature, but has not yet become a reality. Three main obstacles have limited the use of zygotes as a main source of seedlings, (1) the dioecious nature of the algal life cycle which may lead to asynchronous male and female receptacle development and thus different timing of egg and spermatozoa expulsion, (2) the low attachment rate when using zygote-derived germlings with developed rhizoids from wild parental plants for seeding production, and (3) the problem of culturing young germlings in regions where water temperature is high in summer. In this investigation, shifting the timing of receptacle formation earlier than in nature was performed by tumbling the algae in a long-day tank (16-h light per day). Synchronization of egg and spermatozoa expulsion and thereafter fertilization were conducted in indoor tanks. Receptacle formation in constant long days could be shifted by 20 days earlier than in plants cultured on long lines in the open sea, or I month earlier than in plants growing on intertidal rocks. Synchronized expulsion of eggs and spermatozoon led to a high rate of fertilization. This was achieved by tumbling the male and female receptacle-bearing branchlets in the same tank at low density in high irradiance. In two independent trials, a total of 1,400,000 zygote-derived germlings were obtained from 620 g (fresh weight) female sporophytes. The germlings shed from the receptacles were at an identical developmental stage indicating high synchronization of expulsion of eggs and spermatozoon followed by fertilization. Approximately 63% ( +/-9.6%) of the germlings were shed from the receptacle between 16 and 24 It after fertilization and 20% ( +/-11.9%) remained on the receptacle for 3 days after fertilization. Germlings were seeded on string collectors before rhizoids started to elongate and the attachment efficiency was enhanced. Young seedlings reached 800 ( +/-50) mum in length in 25 days at 25 degreesC before they were transferred to open sea cultivation. These results provide the basis of a practical way of seedling production by use of zygote-derived germlings in the commercial cultivation of Hizikia fusiformis. (C) 2004 Elsevier B.V All rights reserved.

Molecular cloning and response to laminarin stimulation of arginine kinase in haemolymph in Chinese shrimp, Fenneropenaeus chinensis

Arginine kinase (AK) was previously reported as a phosphagen-ATP phosphotransferase found in invertebrates. In this study, an 1184 bp cDNA was cloned and sequenced. It contained an open reading frame of 1068 bp that coded for 356 deduced amino acids of AK in Fenneropenaeus chinensis. The calculated molecular mass of AK is 40129.73 Da and pI is 5.92. The predicted protein showed a high level of identity to known AK in invertebrates and creatine kinase from vertebrates, which belong to a conserved family of ATP:guanidino phospho-transferases. In addition, AK protein in plasma of F. chinensis was identified using two-dimensional electrophoresis (2DE) and electrospray ionization mass spectrometry (ESI-MS) according to the calculated molecular mass and pI. AK was significantly decreased in the plasma of F. chinensis at 45 min and recovered at 3 It after laminarin injection as confirmed by 2DE and ESI-MS. The results showed that AK was one of the most significantly changed proteins on two-dimensional gel in the plasma proteins of F. chinensis at 45 min and 3 It after simulation. (c) 2005 Elsevier Ltd. All rights reserved.

Mean sea surface heights of the South and East China Seas from ocean circulation model and geodetic leveling

The mean sea surface heights (sea surface topography) of the South China, East China, Yellow and Bohai Seas are derived from an ocean general circulation model and surface air pressure. The circulation model covers the global oceans, with fine grid (1/6degrees) covering the East Asian marginal seas and coarse grid (31) covering the rest part of the global oceans. The result shows that the China 1985 National Altitude Datum is 24.7 cm above the me-an sea surface height of the world oceans. The mean sea surface in the coastal ocean adjacent to China is higher in the south than in the north. Intercomparison of the model results with the geodetic leveling measurements at 28 coastal tidal stations shows a standard deviation of 4.8 cm and a fitting coefficient of 95.3%. After correction through linear regression, the standard deviation is reduced to 4.5 cm. This indicates that the accuracy of model results is sufficient for practical application. Based on the model results, the mean sea surface heights for the study area with a resolution of 1/6 degree are given. This result also links the mean sea levels at islands with those on the mainland coast and gives the mean sea surface heights at tidal stations in the Taiwan Island, the Dongsha Islands, the Yisha Islands and the Nansha Islands relative to the China 1985 National Altitude Datum.

Relationship between the ennoblement of passive metals and microbe adsorption kinetics in seawater

The relationship between microbial colonization of two kinds of passive metals and ennobling of their corrosion potentials (E-corr) were studied. Two types of passive metal coupons were exposed to natural seawater for about ten days. Under laboratory conditions, all corrosion potentials of the samples ennobled for about 200 mV. Epifluorescence microscopy showed that bacteria adsorption was the main process during about the first day immersion and bacteria reproduced in the following days. The bacteria number increased on the metal surface according to an exponential law and the kinetics of bacteria adsorption at the metal surface during this period was proposed. The ennoblement of E-corr was similar to the increasing bacteria number: E-corr increased quickly during the bacteria adsorption process and increased slowly after biofilms had formed.

紫花冷蒿挥发油成分的研究

采用水蒸气蒸馏法提取, 运用气相色谱-质谱联用法对香叶蒿挥发油化学成分进行了分析, 用气相色谱面积归一化法测定了各成分的质量分数. 结果鉴定出72个化合物, 主要成分为樟脑(33.136%), 桉树脑(23.419%), 6-甲基-2-乙烯基-1,3-庚二烯醛(8.414%), 孟烯醇(3.819%), 桥环萜烯酮(3.276%), 莰烯(2.454%), 1R-α-蒎烯(1.917%), 去甲基丁香酚(1.550%), α-松油醇(1.449%), 冰片(1.674%), β-香叶烯(1.165%), 百里香酚(0.329%)等. 研究表明紫花冷蒿挥发油主要为单萜及其氧化衍生物. 其挥发油成分的研究为挖掘其药用及食品香料工业的应用价值提供了科学依据.

不同放牧强度对鹅绒委陵菜克隆生长特征的影响

在中国科学院海北高寒草甸生态系统定位站,对通过17 a不同放牧强度干扰后金露梅灌丛草甸内鹅绒委陵菜克隆生长特征进行实地调查统计研究.结果显示：长期放牧并增加放牧强度后,植物群落的高度、盖度和草场质量指数下降.随着放牧强度增大,鹅绒委陵菜无性系匍匐茎数目增加,分枝强度加大;基株变矮,逐渐由直立、半直立型变为匍匐状,形态可塑性明显;根长有逐渐增加的趋势;放牧强度对鹅绒委陵菜无性系分株高度、根长和分株叶数影响不显著;间隔子有变短、变粗的趋势,间隔子数目和分株数目有增加的趋势,但影响不显著;轻牧和不牧样地中用于鹅绒委陵菜克隆生长的平均能量投资（分株和匍匐茎的干重及其所占比例）小于重牧样地.表明随放牧强度增大,鹅绒委陵菜无性繁殖能力增强,呈现出典型的生态适应策略.

隆务河流域植物区系研究

隆务河流域共有种子植物65科、329属、970种。区系特征如下：（1）本区系是在高寒类型和寒温、干旱类型兼具的生态环境下形成的。（2）以多年生草要为主、木本植物和一年生植物为辅的植物种类比较丰富。（3）以北温带成分为主的温带性质明显。（4）区系具有年轻性和衍生性质。（5）本区的中国特有种是以我国西南、西北和华北地区为集中分布区或分别为分布中心的种为基础组成的。（6）本区系具有促使物种分化的“过渡生境”的性质和作用，或可称之为“过渡区效应”。区系分析表明，本区系应属与横断山和甘肃南部区系联系密切的青藏高原区系范围，并且在以高原、高山区系成分为主的基础上兼有我国西北寒旱区的荒漠旱生成分。建议是否可在其周围区系更进一步研究的基础上重新确定唐古特地区的界线。

青藏高原东部生态系统土壤碳排放

在青藏高原探讨不同生态系统碳平衡规律及其影响因子并揭示其对全球含碳温室气体变化的影响与响应 ,有重要的现实意义和理论价值。分别在海北高寒草甸生态站、贡嘎山森林生态站和拉萨农业生态站用静态箱法进行了土壤CO2 排放的试验研究。土壤CO2 排放速率日平均值为草甸215.87～329.68mgCO2m -2h -1 ,森林713.72～2102.56mgCO2m -2h -1 ,农田913.05～1135.83mgCO2m -2h-1。土壤碳排放速率日变化 ,在农田和高寒草甸区表现为单峰型 ,均以地方时8∶00～16∶00最高 ,0∶00～8∶00最低。草甸、农田土壤碳排放随着牧草、作物生长发育的加速而逐渐增加 ,越接近成熟 (或枯黄期 )其值越低 ,林区以6～9月的生长旺季为最高。土壤碳排放与温度之间有较好的相关性 ,温度是影响土壤碳排放的重要因子，全球变暖有可能引起高原土壤碳排放的增加。

Uniformity of karyotypes in Ligularia (Asteraceae : Senecioneae), a highly diversified genus of the eastern Qinghai-Tibet Plateau highlands and adjacent areas

Ligularia, a highly diversified genus in the eastern Qinghai-Tibet Plateau and adjacent areas, was chosen as a suitable subject in which to study speciation patterns in this 'hot spot' area at the chromosomal level. Chromosome numbers and karyotypes were studied in 23 populations of 14 species, most of which are endemic to this area. The basic number x = 29 was confirmed for all species. Ligularia virgaurea was found to have diploid and triploid cytotypes, 2n = 58 and 87. Other species are only diploid, with 2n = 58. The karyotypes of all populations within any species, and all species spanning most sections and covering most of the morphological range in Ligularia, are very similar to each other, belonging to type 2A according to Stebbin's classification. This karyotype was also found in its close allies, e.g. Cremanthodium, Ligulariopsis, Parasenecio, and Sinacalia. Aneuploid reduction of chromosome number from 2n = 60 to 58 and karyotypic variation was found in Ligularia and its allies. Such a chromosomal pattern with few polyploids infers that variation of karyotype structure at the diploid level seems to be the predominant feature of chromosomal evolution in this group and sympatric speciation via hybridization and polyploidization has played a minor role in its species diversity. (C) 2004 The Linnean Society of London

关于我院发展技术科学的探讨

技术科学是与国计民生联系很密切的科学,在整个科学技术体系中占有很重要的位置。但是,对技术科学,特别是在我院如何发展等方面的问题上,长期以来意见不一,影响了这门学科的更好发展。周光召院长最近数次指出,今年我们重点要抓好技术科学方向的讨论,研究清楚我院技术科学如何发展的问题。为促进百家争鸣,并供领导部门决策时参考,本期特刊登沈阳自动化研究所所长蒋新松和力学研究所所长薛明伦就这方面问题发表自己见解的文章,期望能引起大家的讨论,欢迎大家踊跃投稿。

菲在土壤／沉积物上的吸附-解吸过程及滞后现象的研究

实验研究了菲在土壤／沉积物上的吸附一解吸过程。CHL土壤和HFH沉积物中有机质的固相^13C CP MAS NMR谱图很相似，表明样品中有机质的组成差异不大；菲在土壤／沉积物上的吸附过程表现出明显的非线性；线性模型不适合拟合菲的吸附等温线，Freundlich模型和双区位反应模型(DRDM)较好地拟合了菲的吸附等温线，其中DRDM模型还清楚地反映菲在低浓度和高浓度下不同的吸附方式；另外，研究表明菲在土壤／沉积物上的解吸过程中存在明显的滞后现象，这可能和土壤／沉积物有机质的异质性和土壤胶团微小孔隙的存在有关。实验研究了菲在土壤／沉积物上的吸附一解吸过程。CHL土壤和HFH沉积物中有机质的固相^13C CP MAS NMR谱图很相似，表明样品中有机质的组成差异不大；菲在土壤／沉积物上的吸附过程表现出明显的非线性；线性模型不适合拟合菲的吸附等温线，Freundlich模型和双区位反应模型(DRDM)较好地拟合了菲的吸附等温线，其中DRDM模型还清楚地反映菲在低浓度和高浓度下不同的吸附方式；另外，研究表明菲在土壤／沉积物上的解吸过程中存在明显的滞后现象，这可能和土壤／沉积物有机质的异质性和土壤胶团微小孔隙的存在有关。

早震旦世大塘坡期锰矿成因新认识

中国南方早震旦世大塘坡期锰矿的形成一直存在热水成因、生物成因、或化学成因的争议。本文通过对贵州松桃早震旦世大塘坡期锰矿的碳、硫同位素和藻类化石的研究，认为早震旦世大塘坡期锰矿的成因是在700-695Ma全球性Sturtian冰期后，由于大气中含有很高的CO2与海洋中的Ca2+, Mn2+反应，造成大量CaCO3和MnCO3快速沉淀，形成“碳酸盐岩帽”（碳酸锰）所致。同时，对大塘坡组藻类化石研究表明，在含锰矿的层位，藻类化石很少，而锰矿层上下，微体藻类化石都很丰富，这说明锰矿成矿与藻类关系并不那么密切。

海南二甲金矿的动力变形成矿作用及构造地球化学模拟实验研究

海南二甲金矿是一个与戈枕韧性剪切带活动明显相关的金矿床。利用构造地球化学方法和构造地球化学模拟试验,研究了戈枕韧性剪切活动与金成矿的关系,结果显示:动力变形作用不仅导致混合岩发生明显的糜棱岩化,而且使矿物成分、化学成分发生明显变化,同时伴随着一定的构造岩流体活动。动力变形中岩石的变形机制可发现有多种,其中以恢复作用比较有利于糜棱岩中金的富集;由动态重结晶石英颗粒统计的差异古应力显示变形强度与Au 富集有显著的正相关性,相关系数达+ 0. 5928 。动力变形不同阶段形成的石英矿物其微量元素含量明显不同,石英中流体包裹体的成分也有明显的差异,反映出不同动力变形阶段流体活动的差异性与金富集密切相关。构造地球化学模拟试验表明,变形作用不仅导致岩石组构的变化,形成微型剪切带、碎粒流带等流动构造,而且伴随有明显的流体活动。这些过程与压溶作用密切相关;另外,动力作用中伴随着金的沉淀、富集,这其中Si 、Fe组分起了重要的作用。