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991.
首先定义熵动量并对其取旋度,再根据波尔兹曼熵公式,推导出二维平面几率流体涡度熵的时变方程,最后根据地球大气的实际,对熵变方程作出了物理解释,并且提出了一个诊断天气系统变化的方法。  相似文献   
992.
Zusammenfassung Auswüchse menschlicher Placenten (12.–14. Woche Schwangerschaft) wurden in Organkultur gehalten. Obwohl sich die histologische Struktur langfristig erhalten lässt, bleibt ein dem menschlichen Wachstumshormon ähnliches Antigen, das in unkultiviertem Syncytiotrophoblast vorhanden ist, nur 10–14 Tage lang am Leben. Dasselbe erscheint vorübergehend in Cytotrophoblastzellen der Placentaauswüchse während der ersten 3 Monate.

We are grateful to ProfessorC. H. Read (Department of Pediatrics, Iowa University) for anti HGH serm; to Dr.P. S. Brown, (Department of Materia Medica, Aberdeen University) for human urinary gonadotrophin preparations; to MissesS. Tait, A. Bruce andF. Duguid for technical assistance. This work was supported by a generous grant to ProfessorA. R. Currie and J. S. b. from the British Empire Cancer Campaign.  相似文献   
993.
碳酸盐岩裂缝对石油和天然气勘探开发具有重要意义,但碳酸盐岩构造裂缝特征描述、形成和影响因素一直是油气储层研究的重点。本文在岩心资料的基础上,综合利用测井解释和分析测试等资料,对阿姆河盆地右岸东部地区侏罗系卡洛夫-牛津阶碳酸盐岩储层内构造裂缝特征进行研究,划分构造裂缝类型及发育期次,明确影响构造裂缝发育的影响因素,分析多期次裂缝对天然气聚集的影响。结果表明:(1)构造裂缝是阿姆河盆地右岸东部侏罗系卡洛夫-牛津阶储层中发育的主要裂缝类型,按照产状分为水平缝、低角度缝、高角度缝和垂直缝;卡洛夫-牛津阶储层构造裂缝总体上走向以NW-SE向为主,但不同裂缝的走向差异性较大,反映了裂缝具有多期发育的特点,不同类型的构造裂缝在产状、密度和规模存在差异,中下侏罗统的XVa1层中最发育,平均裂缝密度为1.48 条/m;构造裂缝的规模普遍较大,在上侏罗统的XVhp层裂缝宽度和裂缝高度最大,平均裂缝宽度约0.08 mm、平均裂缝高度67.1 cm,构造裂缝的倾角多介于40-70°之间;(2)阿姆河盆地右岸东部侏罗系卡洛夫-牛津阶储层构造裂缝的发育程度存在较大的差异,这是由于裂缝的发育不仅受到岩性的控制,还受到多期构造运动的影响,亮晶砂屑灰岩和生物礁灰岩为构造裂缝发育的优势岩性;新近纪的挤压作用强烈,在侏罗系卡洛夫-牛津阶岩心中形成相互交错的网状裂缝,为裂缝期次划分提供有利证据;(3)阿姆河盆地右岸东部侏罗系卡洛夫-牛津阶中构造裂缝形成于燕山晚期到喜山中期,其中晚期裂缝的形成不仅改善了储层物性,也促进天然气聚集和成藏。  相似文献   
994.
给出了具有固定线和的(0,1)-矩阵的最大跳跃数的一个上界和一个下界,证实了Brualdi的猜想,如果k/n,(n mod k)/k,则M(n,k)〈2n-1-〔n/k〕。  相似文献   
995.
1995~1997年在鄂尔多斯沙地采用标志重捕法对小毛足鼠(Phodopusroborovski)的巢区和活动距离进行了调查.结果表明,该鼠的巢区和活动距离雄性分别为3536.1±443.3m2和112.7±8.0m、雌性分别为3375.0±379.8m2和110.1±7.2m,二者均不存在显著的性别差异,也不存在显著的年龄差异和季节差异.巢区面积和活动距离呈极显著的线性相关(r=0.807>r0.01=0.283,df=87).  相似文献   
996.
论理想     
理想是多层次的统一体。我们在进行理想教育时,不能片面强调某一层次而忽略其他层次,犯“以偏概全”的错误。在理想中,核心是社会理想,它使其他层次的理想得到升华,为其指明方向。共产主义理想一定要坚定,但个人理想是可变的;因为只有个人理想可变,才不致因坚执某一设想而偏离大方向。  相似文献   
997.
造纸法烟草薄片废水中污染物的分析   总被引:2,自引:0,他引:2  
运用常规化学分析和红外光谱、色谱-质谱等分析技术对造纸法烟草薄片废水中的污染物进行了分析研究.结果表明,废水成分非常复杂,悬浮物浓度很高,水样偏酸性,但可生化性较好,易腐化变质;有机污染物以纤维素、半纤维素和木质素的水解产物为主,还含有低分子和不挥发性有机酸、烟碱、焦油、酚类物质.这些物质的存在给废水带来较深的颜色,其完全生物降解将是造纸法烟草薄片生产废水达标处理的关键.  相似文献   
998.
A Eu, Dy co-doped SiO2 matrix, white emitting phosphor was prepared by the sol-gel technique. Strong red, green and blue emissions located at 618 nm, 573 nm and 400-550 nm were observed under UV laser excitation at room temperature. Such techniques as FT-IR and TGA-DSC were used to measure the microstructure of the luminescent material. The influence of the preparation techniques on the luminescence property of the Eu, Dy co-doped SiO2 matrix, such as anneal temperature, anneal time, dried atmosphere and the components of the matrix, was systematically studied, and the luminescence mechanism was interpreted. The red emission is the strongest when annealed at 750℃. However, blue emission appears when annealed at 700℃ and is the intensest at 900℃. For the samples dried in vacuum, Eu^3+ is more easily deoxidized to Eu^2+ at lower temperatures, because the samples dried in the air compared with that dried in vacuum need higher temperature to form network structures. Only the SA and SAB matrix annealed at 850℃ had blue emission in the four matrices (SA, SAB, SB, S) xerogel and the emission in the SAB matrix was stronger than that in the SA matrix. This may be due to the eutectic phase formed by the oxide boron, alkaline oxide and alumina in the SAB matrix, which constructs network structures and stabilizes the emission center and enhances the blue emission.  相似文献   
999.
Papaya, a fruit crop cultivated in tropical and subtropical regions, is known for its nutritional benefits and medicinal applications. Here we report a 3x draft genome sequence of 'SunUp' papaya, the first commercial virus-resistant transgenic fruit tree to be sequenced. The papaya genome is three times the size of the Arabidopsis genome, but contains fewer genes, including significantly fewer disease-resistance gene analogues. Comparison of the five sequenced genomes suggests a minimal angiosperm gene set of 13,311. A lack of recent genome duplication, atypical of other angiosperm genomes sequenced so far, may account for the smaller papaya gene number in most functional groups. Nonetheless, striking amplifications in gene number within particular functional groups suggest roles in the evolution of tree-like habit, deposition and remobilization of starch reserves, attraction of seed dispersal agents, and adaptation to tropical daylengths. Transgenesis at three locations is closely associated with chloroplast insertions into the nuclear genome, and with topoisomerase I recognition sites. Papaya offers numerous advantages as a system for fruit-tree functional genomics, and this draft genome sequence provides the foundation for revealing the basis of Carica's distinguishing morpho-physiological, medicinal and nutritional properties.  相似文献   
1000.
Equal amounts of matter and antimatter are predicted to have been produced in the Big Bang, but our observable Universe is clearly matter-dominated. One of the prerequisites for understanding this elimination of antimatter is the nonconservation of charge-parity (CP) symmetry. So far, two types of CP violation have been observed in the neutral K meson (K(0)) and B meson (B(0)) systems: CP violation involving the mixing between K(0) and its antiparticle (and likewise for B(0) and ), and direct CP violation in the decay of each meson. The observed effects for both types of CP violation are substantially larger for the B(0) meson system. However, they are still consistent with the standard model of particle physics, which has a unique source of CP violation that is known to be too small to account for the matter-dominated Universe. Here we report that the direct CP violation in charged B(+/-)-->K(+/-)pi(0) decay is different from that in the neutral B(0) counterpart. The direct CP-violating decay rate asymmetry, (that is, the difference between the number of observed B(-)-->K(-)pi(0) event versus B(+)-->K(+) pi(0) events, normalized to the sum of these events) is measured to be about +7%, with an uncertainty that is reduced by a factor of 1.7 from a previous measurement. However, the asymmetry for versus B(0)-->K(+)pi(-) is at the -10% level. Although it is susceptible to strong interaction effects that need further clarification, this large deviation in direct CP violation between charged and neutral B meson decays could be an indication of new sources of CP violation-which would help to explain the dominance of matter in the Universe.  相似文献   
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