含流体多孔介质中的快速传播断层(英文)

用含流体多孔介质中Ⅱ型运动裂纹对剪切断层的快速传播作了系统分析,对断层不稳定性建立了判据,并对这一理论在地震学中应用的可能性作了探讨。     

用四阶导数分光光度法测定重油中的微量镍

本文通过考察导数分光光度法测定重油微量镍的条件和参数,提出了在PH=3.0的柠檬酸-磷酸氢二钠缓冲溶液存在的条件下,用5-Br-PADAP作显色剂,用四阶导数光度法直接测定重油中微量镍的新方法。本法具有简单、灵敏、准确、不受共存元素干扰的优点,服从比耳定律的线性范围是 0～13μg/25mL。经对不同油样的测定可知,本法的标准偏差均小于1.2ppm,变异系数<6％;与AAS相比,相对误差<15％;回收率为99～114％,符合测定要求。     

Secondary instabilities of linearly heated falling films

Secondary instabilities of linearly heated failing films are studied through three steps. Firstly, the analysis of the primary linear instability on Miladinova's long wave equation of the linearly heated film is performed. Secondly, the similar Landau equation is derived through weak nonlinear theory, and a two-dimensional nonlinear saturation solution of primary instability is obtained within the weak nonlinear domain. Thirdly, the secondary (three-dimensional) instability of the two-dimensional wave is studied by the Floquet theorem.Our secondary instability analysis shows that the Marangoni number has destabilization effect on the secondary instability.     

类人胶原蛋白工程菌质粒稳定性研究

目的研究基因重组大肠杆菌补料分批发酵生产类人胶原蛋白过程中质粒稳定性。方法通过平板复制法,观察质粒稳定性在不同生长周期、卡那霉素浓度和不同比生长速率中的变化。结果质粒稳定性受生长周期、卡那霉素和比生长速率的影响。在μ为0.15、卡那霉素浓度为0.005g/L的情况下,工程菌生产效率最理想。结论通过控制发酵过程中的质粒稳定性可以有效地提高菌体产量和目标蛋白产量。     

水旱交接处护巷煤柱冲击矿压控制

在水采工作面和旱采工作面交接的护巷煤柱处,极易发生冲击矿压事故.通过对冲击矿压机理的分析,认为冲击矿压的发生是由于积聚较高能量的受载煤体裂纹不稳定扩展所致.提出了增加卸载区的范围,促使煤体裂纹稳定扩展,降低单位煤体储能,从而控制冲击矿压发生的原理.给出了该条件下增加煤体孔隙率,减少瓦斯、空气流通通道的防治原则.在此基础上,给出了分段治理,注水和注浆相结合的防治方案.工程实践证明该方案是切实有效的.     

矿井煤岩体变形失稳问题的研究

本文对矿井中几种变形失稳现象:煤体冲击地压、矿震、顶底板冲击地压及煤与瓦斯突出,分别建立了煤岩体压缩、剪切、拉伸、固液耦合失稳模型及失稳判别准则,初步构画了矿井煤岩体失稳问题的框架.     

Peat record reflecting Holocene climatic change in the Zoigê Plateau and AMS radiocarbon dating

Through the use of reliable AMS dating of high resolution (15–30 years) peat and the establishment of monsoon climate proxies sequence, we have been able to recognize several cold, dry events in the Tibetan Plateau during the Holocene. The more obvious ones occurred around 12800, 11300, 10200, 9580, 8900, 6400, 4400, 3700, 2800 and 1500 cal. aBP. These events correlate well with both ice rafting events recorded in high latitude North Atlantic Ocean sediment cores and cooling events in the low latitude SST. Spectral analysis indicates high frequency climate variation on centennial-millennial time scale during the Holocene. This further reflects Holocene climate instability and the existence of centennial-millenium scale rhythm in mid latitude areas as well.     

The mutator phenotype theory can explain the complex morphology and behaviour of cancers

Almost all solid malignancies exhibit complex cytological and architectural abnormalities, which vary from cell to cell and area to area within the same tumour, and between tumours of the same type. The degrees of these abnormalities do not correlate perfectly with the biological behaviour (especially growth rate and metastatic potential) among the various tumour types. These features of tumours have long been considered to invalidate simple mutational or 'abnormal gene expression' (epigenetic) theories of carcinogenesis. The 'mutator phenotype/clonal selection' hypothesis is based on the now well-established phenomenon of genetic instability of cancer cells, and proposes that this instability is an essential requirement for the development of tumours, and not an irrelevant side-effect of some other process. This paper argues that this hypothesis can provide a satisfactory explanation for the diverse histological and biological features of solid malignancies. Further, because virtually all solid tumours are histologically abnormal, genetic instability is likely to be essential for the malignant process. The concepts of mutator phenotype and clonal selection are therefore supported. Received 8 April 2002; accepted 25 April 2002     

浅谈公路黄土边坡坡面防护

在前人进行边坡优化设计的基础上充分考虑了坡面的不稳定因素,对边坡的坡角和坡高等进行设计,并总结了黄土地区边坡坡面的防治措施。