用于砾石夹层钻进的新型PDC钻头的研制与使用          下载免费PDF全文

李天明  李大佛  陈洪俊  雷艳  刘红旗 《探矿工程》2006,33(8):57-60,63

无压浸渍工艺生产的PDC石油钻头钻遇砾石夹层不适应。根据砾石夹层砾石坚硬、软硬互层、非均质、研磨性强的特点，研究了新型PDC钻头，在钻头结构上主要采取外抛内锥带辅助切削齿的结构形式，在复合片上主要采用非平面结合方式，即采用双向多条直槽非平面结合。按此方案设计与生产了3只钻头，分别在3口井试用，直接钻穿砾石夹层馆陶组地层井段，钻井效率提高26%，突破了砾石夹层钻进不能使用PDC钻头的禁区。  相似文献   

Organic pollutants associated with macromolecular soil organic matter: Mode of binding   总被引：2，自引：0，他引：2  

H. H. Richnow  R. Seifert  J. Hefter  M. Link  W. Francke  G. Schaefer  W. Michaelis   《Organic Geochemistry》1997,26(11-12)

A study of ether-linked moieties in macromolecular bound residues of polycyclic aromatic hydrocarbons (PAH) generated in bioremediation experiments was performed using high temperature hydrolysis degradation with subsequent analysis of the products by GC-MS. This hydrolysis reaction was specifically designed to cleave ether bonds including relatively stable diarylether structures. Among the reaction products, aromatic alcohols representing typical microbiologically derived metabolites of PAH were found in addition to natural compounds. Thus, parts of the bound residues appeared to be linked within the macromolecular material by ether bonds. Model experiments with an oxidoreductase enzyme and aromatic alcohols indicate the formation of these ether bonds to be an enzyme-catalysed process.  相似文献   

Computational methods for fitting statistical distribution models of multi-site binding equilibria     

Rudolph S. Parrish  E. Michael Perdue 《Mathematical Geology》1989,21(2):199-219

Statistical distribution models of multi-site binding equilibria have potential applicability in the study of acid-base and metal complexation chemistry of humic substances in soils, sediments, and natural waters. A mathematical derivation is presented for the general continuous model for the case of proton binding; computational methods are described for fitting numerically the parameters in such models. Among models considered are those based on nontruncated, truncated, and bimodal (mixed) distributions. Specific emphasis is placed on Gaussian distribution models.  相似文献   

浅谈市(州)普通地图集的设计   总被引：1，自引：0，他引：1  

鲁明东 《地理空间信息》2006,4(5):86-88

介绍了设计编制地图集中的若干问题:如何确定开本及比例尺大小,如何设计整饰与装帧等。提出了设计编制地图集也应看成是一项科学研究过程的观点。  相似文献   

Humic Ion-Binding Model VI: An Improved Description of the Interactions of Protons and Metal Ions with Humic Substances   总被引：1，自引：0，他引：1  

Edward Tipping 《Aquatic Geochemistry》1998,4(1):3-47

Humic Ion-Binding Model VI, a discrete site/electrostatic model of the interactions of protons and metals with fulvic and humic acids, is applied to 19 sets of published data for proton binding, and 110 sets for metal binding. Proton binding is described with a site density, two median intrinsic equilibrium constants, two parameters defining the spread of equilibrium constants around the medians, and an electrostatic constant. Intrinsic equilibrium constants for metal binding are defined by two median constants, log K_MA and log K_MB, which refer to carboxyl and weaker-acid sites respectively, together with a parameter, LK₁, defining the spreads of values around the medians. A further parameter, LK₂, takes account of small numbers of strong binding sites. By considering results from many data sets, a universal average value of LK₁ is obtained, and a correlation established between log K_MB and log K_MA. In addition, a relation between LK₂ and the equilibrium constant for metal-NH₃ complexation is tentatively suggested. As a result, metal-binding data can be fitted by the adjustment of a single parameter, log K_MA. Values of log K_MA are derived for 22 metal species. Model VI accounts for competition and ionic strength effects, and for proton-metal exchange.  相似文献   

校园网IP地址绑定系统的研究与设计     

陈玉民  代成琴  王海洁 《中国海洋大学学报(自然科学版)》2008,(Z1)

IP地址绑定和IP用户管理是校园网管理员的主要工作,作者介绍哈尔滨工业大学校园网IP地址绑定和IP用户管理系统的设计思路及实现技术,该系统是采用J2EE技术和Struts+Hibernate框架实现的B/S结构WEB应用系统,用于校园网用户的IP地址分配I、P地址绑定及IP用户管理等方面。该系统的实现与应用大大提高了网络管理员的工作效率、避免了操作失误、改善了对用户的服务质量。  相似文献   

大菱鲆CD55负调控补体激活及其广谱细菌结合能力     

吴蒙  李墨非  孙黎 《海洋科学》2022,46(7):24-31

CD55蛋白在哺乳动物中是一种补体调控因子,但其在鱼类中的功能未知。本研究探索了大菱鲆(Scophthalmus maximus) CD55(SmCD55)蛋白的功能。结果表明,SmCD55蛋白由344个氨基酸残基构成,含有一个N端信号肽和3个补体调控蛋白(CCP)功能域。SmCD55基因在大菱鲆多种组织中均有表达,其中,在肌肉中表达量最低,在脑组织的表达量最高。通过原核表达获得了重组的SmCD55(rSmCD55)蛋白,发现rSmCD55蛋白能够抑制大菱鲆血清的溶血活性和杀菌活性,表明其负调控补体系统的激活。此外,本研究还发现rSmCD55蛋白可以结合包括重要水产病原菌迟缓爱德华氏菌(Edwardsiella tarda)、荧光假单胞杆菌(Pseudomonas fluorescens)、鳗弧菌(Vibrio anguilla­rum)、哈维氏弧菌(Vibrio harveyi)和海豚链球菌(Strep­tococcus iniae)在内的多种细菌,其中与哈维氏弧菌的结合能力最强。以上这些研究结果丰富了鱼类补体系统的理论知识,加深了对鱼类补体激活调控的了解。  相似文献   

Root structure,distribution and biomass in five multipurpose tree species of Western Himalayas   总被引：1，自引：0，他引：1  

Kartar Singh VERMA  Sandeep KOHLI  Rajesh KAUSHAL  Om Parkash CHATURVEDI 《山地科学学报》2014,11(2):519-525

【Title】

【Author】

【Addresses】1

The tree root distribution pattern and biomass of seventeen year old trees of Grewia optiva, Morus alba, Celtis australis, Bauhinia variegata and Robinia pseudoacacia were studied by excavation method. B. variegata roots penetrated to a maximum depth of 4.78 m, whereas, M. alba roots were found down to 1.48 m depth. Lateral spread was minimum in B. variegata （1.10 m）and maximum inR. pseudoacacia （7.33 m）. Maximum root biomass of 6.30 kg was found in R. pseudoacacia and minimum （2.43 kg） was found in M. alba. For four species viz.,G. optiva, M. alba, C. australis andR. pseudoacacia, 68%-87% root biomass occurred within top 0-30 cm soil depth, but forB. variegata this was only45%. The soil binding factor was maximum in G. optiva and minimum in B. variegata. Soil physico-chemical properties also showed wide variation. The study suggests thatB. variegata with a deep root system is the most suitable species for plantation under agroforestry systems. R. pseudoacacia and G. optiva with deep root systems, more lateral spread and high soil binding factor are suitable for plantation on degraded lands for soil conservation.  相似文献   

中国明对虾精氨酸激酶与白斑综合征病毒结构蛋白VP31的作用初探     

刘超  赵培  梁艳  高强  刘升平  黄倢 《海洋科学》2014,38(3):104-110

白斑综合征病毒(white spot syndrome virus,WSSV)是危害对虾的主要病原,给全球水产养殖业带来了巨大经济损失。为研究阻断WSSV的途径,前期研究WSSV与宿主相结合的受体蛋白发现,白斑综合征病毒囊膜蛋白VP31可以与中国明对虾(Fenneropenaeus chinensis)精氨酸激酶(FcAK)发生结合作用。精氨酸激酶(AK)通过调节无脊椎动物体内磷酸精氨酸与三磷酸腺苷(ATP)之间平衡在能量代谢、储存和利用方面具有重要作用。作者通过重组表达的rFcAK与rVP31的far-Western blotting分析,证实两者有结合作用,此外,rFcAK还与WSSV的VP19、VP28等6种结构蛋白有结合作用。双向电泳分析观察到,rFcAK与rVP31的磷酸化反应后,rVP31部分发生pI降低现象,提示rVP31可能发生了磷酸化。生物信息学分析表明VP31存在21个精氨酸残基,FcAK具有12个精氨酸结合位点,这可能为VP31和FcAK的结合活性提供了靶位。为进一步研究WSSV与宿主结合机理及阻断感染的机制提供思路。  相似文献   

半水磷石膏的矿物学特征     

杨林  曹建新  刘亚明 《岩石矿物学杂志》2015,34(6):827-834

讨论了半水磷石膏的化学组成、矿物组成、热性能、微观形貌以及胶凝性能。结果表明:半水磷石膏中主要化学组成为CaO和SO3,其总量达到70%,含有少量的结晶水和P2O5;半水磷石膏中含有放射性元素,但未超过GB/T6566-2010《建筑材料放射性核素限量》的限值;半水磷石膏矿物组成主要是α型的烧石膏相,但其放热峰面积小,主要以不同取向的硫酸钙晶体的聚晶形式存在,胶凝性能差,烘干强度仅为0.38 MPa。半水磷石膏与二水石膏制备的α型半水石膏在微观形貌上存在较大差异,将其直接应用于建筑材料还有待于进一步研究。  相似文献