地衣芽孢杆菌De株的胞外产物对凡纳滨对虾脂肪酶活性影响的体外实验

为探析芽孢杆菌提高水产动物的消化酶活性的作用机制,在体外条件下实验研究了地衣芽孢杆菌(Bacillus licheniformis)De株的胞外产物(Extracellular products,ECP)对凡纳滨对虾(Litopenaeus vannamei)脂肪酶活性的影响.以半透膜法收集地衣芽孢杆菌De株的胞外产物,以匀浆离心法提取凡纳滨对虾成虾的肝胰腺和肠道消化酶,将胞外产物和对虾消化酶按体积比10:90混合,于体外条件下研究不同温度、pH及胞外产物添加量对样品脂肪酶活性的影响.结果显示,地衣芽孢杆菌胞外产物添加组的脂肪酶活性明显高于对照组(P＜0.05),在其最适的pH8～10下对虾肝胰腺和肠道的脂肪酶活性分别提高了118%和136.5%;而在其最适温度30℃～50℃时样品的脂肪酶活性则比两对照组分别提高了394.2%和195.1%.研究还发现,胞外产物添加组的脂肪酶活性与样品中胞外产物的添加量呈正相关.可见,在体外条件下地衣芽孢杆菌De株的胞外产物对凡纳滨对虾的脂肪酶活性具有促进作用.     

Environmentally-assisted cracking behaviour in the transition region of an Alloy182/SA 508 Cl.2 dissimilar metal weld joint in simulated boiling water reactor normal water chemistry environment

The stress corrosion cracking (SCC) and corrosion fatigue behaviour perpendicular and parallel to the fusion line in the transition region between the Alloy 182 Nickel-base weld metal and the adjacent SA 508 Cl.2 low-alloy reactor pressure vessel (RPV) steel of a simulated dissimilar metal weld joint was investigated under boiling water reactor normal water chemistry conditions. A special emphasis was placed to the question whether a fast growing interdendritic SCC crack in the highly susceptible Alloy 182 weld metal can easily cross the fusion line and significantly propagate into the adjacent low-alloy RPV steel. Cessation of interdendritic SCC crack growth was observed in high-purity or sulphate-containing oxygenated water under constant or periodical partial unloading conditions for those parts of the crack front, which reached the fusion line. In chloride containing water, on the other hand, the interdendritic SCC crack in the Alloy 182 weld metal very easily crossed the fusion line and further propagated with a very high rate as a transgranular crack into the heat-affected zone and base metal of the adjacent low-alloy steel. The observed SCC cracking behaviour at the interface correlates excellently with the field experience of such dissimilar metal weld joints, where SCC cracking was usually confined to the Alloy 182 weld metal.     

5G边缘计算商用部署和运维关键技术

由于部署地点和应用场景的差异,边缘计算系统存在一体化和云化两种部署模式,导致系统架构、关键技术要求以及运维方式也各不相同.首先分析了两种模式下的应用场景、特征及对系统的需求,其次,从硬件、云化基础设施平台、边缘PaaS平台、安全以及运维等方面对两种模式做了深入分析,最后在上述分析基础上,从商用角度明确了边缘计算在两种部...     

兴古潜山油藏水平井完井技术试验

兴古潜山油藏位于辽河坳陷西部凹陷中段,属于块状裂缝型油藏。近几年为了提高开发效果,辽河油田在该区块布置了较多的水平井。已建成的水平井大多采用裸眼完井和筛管完井。为解决水平井在完井过程中尾管段常发生封隔失效的问题,同时提高完井技术和工具对该区块水平井深度大(多在5000m以上)、井眼曲率高(7°/30m以上)的适应性,进行了遇油膨胀封隔器完井试验、液力膨胀封隔器完井试验及水平井分段完井综合试验。试验结果表明:管外封隔器入井系列试验实现了兴古潜山水平井分段完井的目标,为今后该区块的分层分段开发打下了基础;在兴古潜山油藏水平井分段完井方案中,脚跟处的管外封隔器用浸泡膨胀封隔器效果较好;管外封隔器的使用及分段完井技术的应用,可以有效减少投产前的作业量。由于分段完井技术尚处于试验期,建议进一步试验研究。     

Measurement of steady-state hydrogen electrode reactions on Alloys 600 and 690 tubes

The steady-state polarization measurements for HER and HOR were carried out in order to obtain the effects of hydrogen pressure, solution pH, and temperature on the current densities of Alloys 600 and 690, respectively. Optimization was performed to obtain the electrokinetic parameters of HER and HOR on Alloys 600 and 690 such as forward and reverse transfer coefficients and equilibrium corrosion densities. From the optimization process, the activation energies, E_ac, of both hydrogen reactions on the surfaces of the Alloys 600 and 690 tubes were obtained as 30.5 kJ/mole on the surface of Alloy 600 tube and 35.6 kJ/mole on Alloy 690 tube. Furthermore, the equilibrium exchange current densities of hydrogen electrode reaction, i₀(H₂), on the surface of the Alloys 600 and 690, respectively, were proposed as functions of hydrogen pressure, solution pH, and temperatures.     

列车ECP电控空气制动系统的排序方法探讨

对列车ECP电控空气制动系统的排序方法进行了研究，详细探讨了列车排序的硬件设计与软件设计，用于确定车辆位置与方位。     

SPECT评价体外反搏治疗缺血性脑血管病

２２例经临床及实验室检查诊断为缺血性脑血客病患者在体外反搏治疗前后用＾９９ｍＴｃ－双胱乙酯行ＳＰＥＣＴ局部脑血流断层显像。治疗前显示ｒＣＢＦ缺血改变５４处，治疗后明显改善的２０处，占３７．０％．部分改善１９处，占３５．２％，无效１５处，占２７．８％，总有效率为７２．２％。结果表明，ＳＰＥＣＴ可用于缺血性脑血管病的早期诊断，还可用以评价缺血性脑血管病的疗效。     

Electrochemical planarization of patterned copper films for microelectronic applications

Electrochemical polishing (ECP) of copper (Cu) using solutions of phosphoric acid, sulfuric acid, sodium chloride, ethylene glycol, and hydroxyethylidenediphosphonic acid (HEDP), with or without organic and inorganic additives, has been investigated as an alternative to chemical mechanical polishing (CMP) for integration of low-k dielectrics in microelectronic devices. Copper anodic polarization curves in these solutions were measured. ECP of Cu bulk and thin films in these solutions was evaluated with atomic force microscopy and scanning electron microscopy. It was shown that most of the solutions studied have polarization curves with a limiting current plateau characteristic of ECP. Among them, phosphoric acid, HEDP, and phosphoric acid solutions with ethylene glycol, sodium tripolyphosphate, and Cu oxide as additives produced the best electropolished surfaces (mean roughness: R _a<10 nm) on bulk Cu. However, satisfactory ECP of electroplated patterned Cu films on silicon wafers were achieved only with an electrolyte that produced a salt film at the anode surface. Based on these experimental results, ECP mechanisms and optimal conditions for ECP of patterned Cu films plated on silicon wafers are presented. This paper was presented at the 2nd International Surface Engineering Congress sponsored by ASM International, on September 15–17, 2003, in Indianapolis, Indiana, and appears on pp. 389–97 of the Proceedings.     

适于垃圾文本流过滤的条件概率集成方法

通过用于垃圾文本流过滤的在线文本分类研究,提出了一种新的条件概率集成方法。采用语汇序列表示文本,使用索引结构存储分类知识,设计实现了分类模型的在线训练算法和在线分类算法。抽取电子邮件和手机短信的多种文本特征,分别在TREC07P电子邮件语料和真实中文手机短信语料上进行了垃圾信息过滤实验。实验结果表明,提出的方法能够获得很好的垃圾信息过滤效果。     

脉冲电流对钢液凝固过程中夹杂物迁移行为的影响

在钢液凝固过程中施加脉冲电流,通过观察和分析凝固试样中夹杂物的形貌、数量、尺寸和分布状态等,以研究施加脉冲电流对钢中夹杂物迁移行为的影响。结果表明,在脉冲电流的影响下,钢液凝固初期形成的晶核会发生脱落而形成结晶雨;在晶核下落过程中,钢中夹杂物也会随之向下部迁移。随着脉冲电流强度的逐渐增加,钢锭上、中部夹杂物逐渐减少,晶粒尺寸变小。在本试验条件下,当电流强度为56.6 A/cm2 时,钢锭上、中部夹杂物的总面积和总数量分别比未施加脉冲电流时的降低46.9% 和35.6%。对于夹杂物含量要求较高的钢种而言,在钢锭凝固过程中施加脉冲电流,控制结晶雨的形成和迁移过程不失为一种有效去除钢中夹杂物、提高钢锭质量的技术手段。