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71.
中原油田东濮凹陷地区发育相当成熟的岩层要求套管单轴抗挤强度不低于103MPa,以抵御恶劣的地质条件。为了能和上下管柱设计使用的API标准规格的Φ177.8mm×10.36mm以及Φ177.8mm×11.51mm套管方便地连接,设计了非API标准规格的Φ180mm×11.51mm套管。采用纯净钢技术制造了这种规格的BG160TT超高强度抗挤套管。试制结果表明:该套管屈服强度不低于1210MPa,冲击功不小于110J,抗挤强度不低于110MPa。该超高强度抗挤套管已在中原油田东濮凹陷地区成功下井使用。 相似文献
72.
《International Journal of Hydrogen Energy》2020,45(6):3785-3794
One-dimensional premixed freely-propagating flames for (CH4+CO2/H2O)/air(79%N2+21%O2) mixtures were modeled using ChemkinⅡ/Premix Code with the detailed mechanism GRI-Mech 3.0. The investigation of the effects of CO2 and steam addition on the H2 intermediate formation and NO emission was conducted at the initial conditions of 1 atm and 398 K. Both physical and chemical effects of CO2, H2O on laminar burning velocities and adiabatic flame temperatures were also analyzed. The calculations show that with the increase of αCO2 and αH2O, both physical and chemical effects of CO2 and H2O result in the reduction of laminar burning velocities (LBVs) and adiabatic flame temperatures (AFTs) in which the chemical effects of CO2 addition are more significantly than H2O. Especially, the chemical effects of steam promote the increase of AFTs and the influence in rich BG65 flames are larger than in methane. With a proper amount of H2O addition, the chemical effects of H2O on the peak concentration of H2 are more significantly than physical at Φ = 1.2. Moreover, CO2, steam and their mixture addition have significant reduction on the NO emission. The most sensitive reaction for the formation of H2 and NO emission were determined. The responsible reactions for H2 formation and NO emission are R84 OH + H2 <=> H + H2O and R240 CH + N2 <=> HCN + N (a prompt routine), respectively. 相似文献
73.
Cheng Li R. Venkatesan Howard M. Heys 《International Journal of Communication Systems》2007,20(9):1011-1036
This paper presents the design and implementation of a new scalable cell‐based multicast switch fabric for broadband communications. Using distributed control and modular design, the multicast balanced gamma switch features a scalable, high performance architecture for unicast, multicast and combined traffic under both uniform and non‐uniform traffic conditions. The important design characteristic of the switch is that a distributed cell replication function for multicast cells is integrated into the functionality of the switch element with the self‐routing and contention resolution functions. Thus, no dedicated copy network is required. In the paper, we discuss in detail the design issues associated with the multicast functionality of the switch using 0.18 µm CMOS technology and discuss the scalability of the switch in terms of architectural, implementation, and performance scalability. Synthesized results are provided for measures of circuit complexity and timing. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
74.
75.
YuFeng Gao Lei Hang Jia He Fei Zhang Leon Van Paassen 《Geotextiles and Geomembranes》2021,49(3):646-656
The pullout resistance of a geosynthetic reinforcement is crucial for the design of reinforced soil structures. In this paper, an innovative concept, biocementation-geosynthetic (BG) system is presented, in which biocementation is used in combination with geosynthetic to increase the pullout resistance of the geosynthetic reinforcement. A series of pullout tests were conducted in laboratory to obtain the pullout behavior of the biocementation-geosynthetic system. From the pullout test results, it was found that the BG system was more efficient in enhancing the pullout resistant as compared with the ordinary geosynthetic (OG) system. For both geosynthetic strips and biaxial geogrid, the BG system had a higher pullout resistance at various levels of relative density. The BG system with only about 0.65% calcite produced by the biocementation process has a 13%–38% improvement in the pullout resistance compared to the OG system. In addition, the interface shear strength parameters (the adhesion ca and average interface friction angle ?) of the BG system are also higher than that of the corresponding OG system in most cases, indicating the better interface performance of the BG system. 相似文献
76.
采用Qpixel公司推出的高性能SoC芯片QL202B设计了一个H.264标准的便携式实时编解码器系统,重点介绍了系统和硬、软件模块的结构和设计,在测试的基础上介绍了这个编解码器的特点及应用. 相似文献
77.
有时延约束的路由算法研究 总被引：1，自引：0，他引：1
高速多媒体网络中的路由问题是有QoS约束的路由问题,满足一个或多个约束的路由问题是NP－完全问题。BG算法是一种有效的启发式算法,适用于单约束问题,可以得到问题的次优解。将BG算法与多标号算法相结合,提出了两种改进的多标号算法。仿真证明文中的算法可以有效地缩小多标号算法搜索范围,从而降低算法的复杂度,具有一定的实际意义。 相似文献
78.
安徽某难选硫化铜矿石浮选试验研究 总被引：4，自引：0，他引：4
安徽某热液蚀变的接触变质原生硫化铜矿矿石因性质复杂而难选,以常用浮选药剂按常规铜硫混浮铜硫分离流程进行选矿试生产不能达到设计指标,致使选厂不能正常投产。为此,对该矿石进行了合理浮选工艺流程和新药剂制度的试验研究。试验采用自行研制的新型酯类捕收剂QL先脱除易浮脉石,然后用复合捕收剂MC进行铜硫混浮、以石灰为抑制剂进行铜硫分离,获得了铜品位22．78％、回收率86．80％的铜精矿,超过铜精矿铜品位21．30％、回收率85．50％的设计指标。新的工艺流程适应矿石性质,药剂制度简单、用量少,易于工业化。 相似文献
79.
Yilong Feng Zhenyu Luo Ranran Huang Xueming Yang Xuejiao Cheng Wenli Zhang 《International journal of molecular sciences》2022,23(15)
DNA G-quadruplexes (G4s) are non-canonical four-stranded DNA structures involved in various biological processes in eukaryotes. Molecularly crowded solutions and monovalent cations have been reported to stabilize in vitro and in vivo G4 formation. However, how K+ and Na+ affect G4 formation genome-wide is still unclear in plants. Here, we conducted BG4-DNA-IP-seq, DNA immunoprecipitation with anti-BG4 antibody coupled with sequencing, under K+ and Na+ + PEG conditions in vitro. We found that K+-specific IP-G4s had a longer peak size, more GC and PQS content, and distinct AT and GC skews compared to Na+-specific IP-G4s. Moreover, K+- and Na+-specific IP-G4s exhibited differential subgenomic enrichment and distinct putative functional motifs for the binding of certain trans-factors. More importantly, we found that K+-specific IP-G4s were more associated with active marks, such as active histone marks, and low DNA methylation levels, as compared to Na+-specific IP-G4s; thus, K+-specific IP-G4s in combination with active chromatin features facilitate the expression of overlapping genes. In addition, K+- and Na+-specific IP-G4 overlapping genes exhibited differential GO (gene ontology) terms, suggesting they may have distinct biological relevance in rice. Thus, our study, for the first time, explores the effects of K+ and Na+ on global G4 formation in vitro, thereby providing valuable resources for functional G4 studies in rice. It will provide certain G4 loci for the biotechnological engineering of rice in the future. 相似文献
80.
以XML文档发布关系数据 总被引：2，自引：0，他引：2
万常选 《计算机应用与软件》2002,19(8):30-33,50
本文对以XML文档发布关系数据的新技术进行了综述，主要分析了两种发布关系数据到XML文档的语言描述及其实现技术，以及它们的优缺点，一种是利用并扩展SQL的功能来描述这种转换，嵌套的SQL表达式被利用来描述嵌套，扩展的SQL标量及聚集函数被利用来描述XML元素构造，实现将关系数据转换为XML文档，另一种是利用RXL（Relational to XML Transformation Language)语言来定义一个关系数据库的XML视图，该XML视图是虚的，其它应用可再利用XML查询语言XML－QL在虚拟的视图上构造一个查询，抽取XML视图中的数据片断并对抽取的部分进行物化，实现将关系数据转换为XML文档。 相似文献