用赤铁细精矿生产高质量烧结矿的工业实践

鞍钢东鞍山烧结厂在进行了全面技术革新和设备改造后,烧结厂在技术装备、工艺水平、自动控制和环保节能等方面都有了显的提高。采用优化配矿、低温烧结和小球烧结等多项措施,解决了浮选赤铁细精矿混匀难、造球难、烧结难的难题。摸索出了一套浮选赤铁细精矿烧结生产的方法,开创了历史上效益最好、产量最高的生产局面。生产的高质量烧结矿满足了现代化大高炉的要求。     

一种不受波速影响的单端行波测距方法

分析了架空线路发生故障后行波的传播过程以及行波折、反射原理。针对双端测距的不足提出了一种基于分析单端行波前三个波头的故障测距新方法。首先,在线路两端安装实时通信装置,根据两端的第一个波头的到达时间先后识别故障点离两端母线哪一端更近,然后利用单端行波测距方法记录M端母线接收到的前三个波头到达的绝对时间,确定故障点类型,经过数学变形消去会对测距结果产生误差的主要影响因素行波传播速度 ,求出故障点位置。所提方法避开了单端行波测距中区分第二个波头性质的难题,消除了双端原理测距中线路两侧准确时间同步问题对测距精度的     

全金属封装光纤光栅的温度传感特性研究

针对利用聚合物作为衬底材料或胶粘剂进行封装的光纤Bragg光栅(FBG)传感器在长期使用过程中出现的老化、蠕变等问题,考虑采用熔点较低的锡焊完成了1529.0 nm FBG的全金属封装;利用水浴加热的方法在19～60℃的温度范围内,测得经封装后的FBG的温度灵敏度为34.0 pm/℃,是封装前的3.3倍,且有较好的重复性.     

High pressure effects on proteolytic and glycolytic enzymes involved in cheese manufacturing

The activity of chymosin, plasmin, and Lactococcus lactis enzymes (cell envelope proteinase, intracellular peptidases, and glycolytic enzymes) were determined after 5-min exposures to pressures up to 800 MPa. Plasmin was unaffected by any pressure treatment. Chymosin activity was unaffected up to 400 MPa and decreased at 500 to 800 MPa. Fifty percent of control chymosin activity remained after the 800 MPa treatment. The lactococcal cell envelope proteinase (CEP) and intracellular peptidase activities were monitored in cell extracts of pressure-treated cells. A pressure of 100 MPa increased the CEP activity, whereas 200 MPa had no effect. At 300 MPa, CEP activity was reduced, and 400 to 800 MPa inactivated the enzyme. X-Prolyl-dipeptidyl aminopeptidase was insensitive to 5-min pressure treatments of 100 to 300 MPa, but was inactivated at 400 to 800 MPa. Aminopeptidase N was unaffected by 100 and 200 MPa. However, 300 MPa significantly reduced its activity, and 400 to 800 MPa inactivated it. Aminopeptidase C activity increased with increasing pressures up to 700 MPa. High pressure did not affect aminopeptidase A activity at any level. Hydrolysis of Lys-Ala-p-NA doubled after 300-MPa exposure, and was eliminated at 400 to 800 MPa. Glycolytic enzyme activities of pressure-treated cells were evaluated collectively by determining the titratable acidity as lactic acid produced by cell extracts in the presence of glucose. The titratable acidities produced by the 100 and 200 MPa samples were slightly increased compared to the control. At 300 to 800 MPa, no significant acid production was observed. These data demonstrate that high pressure causes no effect, activation, or inactivation of proteolytic and glycolytic enzymes depending on the pressure level and enzyme. Pressure treatment of cheese may alter enzymes involved in ripening, and pressure-treating L. lactis may provide a means to generate attenuated starters with altered enzyme profiles.     

Recirculating immunomagnetic separation and optimal enrichment conditions for enhanced detection and recovery of low levels of Escherichia coli O157:H7 from fresh leafy produce and surface water

The objective of this study was to develop a rapid, simple method for enhanced detection and isolation of low levels of Escherichia coli O157:H7 from leafy produce and surface water using recirculating immunomagnetic separation (RIMS) coupled with real-time PCR and a standard culture method. The optimal enrichment conditions for the method also were determined. Analysis of real-time PCR data (C(T) values) suggested that incubation of lettuce and spinach leaves rather than rinsates provides better enrichment of E. coli O157:H7. Enrichment of lettuce or spinach leaves at 42 degrees C for 5 h provided better detection than enrichment at 37 degrees C. Extended incubation of surface water for 20 h at 42 degrees C did not improve the detection. The optimized enrichment conditions were also employed with modified Moore swabs, which were used to sample flowing water sites. Positive isolation rates and real-time PCR results indicated an increased recovery of E. coli O157:H7 from all samples following the application of RIMS. Under these conditions, the method provided detection and/or isolation of E. coli O157:H7 at levels as low as 0.07 CFU/g of lettuce, 0.1 CFU/g of spinach, 6 CFU/100 ml of surface water, and 9 CFU per modified Moore swab. During a 6-month field study, modified Moore swabs yielded high isolation rates when deployed in natural watershed sites. The method used in this study was effective for monitoring E. coli O157:H7 in the farm environment, during postharvest processing, and in foodborne outbreak investigations.     

绥中36-1油田泡沫凝胶调驱体系研究与性能评价

针对绥中36-1海上油田强非均质性和大孔道稠油油藏提高采收率的需求,开展了自生气泡沫凝胶调驱技术研究。通过waring-blender搅拌法测定热泡沫凝胶体系各组分对起泡和稳泡性能的影响,进行了抗盐、抗钙镁、耐温性能评价,确定了泡沫凝胶体系配方,即0.3%(w)起泡剂+300mg/L交联剂+3000mg/L聚丙烯酰胺+5%(w)生气体系+1000mg/L稳定剂,并进行了封堵、驱油、可解性能评价实验。实验结果表明,该体系在SZ36-1油田油藏条件下封堵率大于95%,驱油效率比水驱提高25%以上,体系可解率大于90%。     

油气井套管CO2点状腐蚀剩余强度分析

在高温高压含CO₂油气井中，套管腐蚀是相当严重的，CO₂腐蚀以点状（坑状）腐蚀为主，腐蚀的形状大多呈球窝形。为此，文章建立CO₂点蚀模型，以点蚀后套管的剩余强度为出发点，应用弹塑性有限元方法分析了点蚀套管的抗挤强度、抗内压强度、抗拉强度的变化。同时运用无因次分析和曲线拟合方法，建立了点蚀套管无因次剩余强度与套管点蚀无因次形状参数之间的关系曲线以及拟合曲线。有限元程序的计算结果与试验结果具有良好的一致性。结果表明，点蚀套管强度剩余的百分数并不正比于套管剩余壁厚百分数，剩余强度曲线呈降-稳-降三段式变化。由多腐蚀点干扰分析发现，多腐蚀点同时存在时，应力分布及其大小与单腐蚀点情况相差不大。     

含有银纳米膜的棱镜中光束古斯-汉欣位移效应研究

古斯-汉欣位移是一种灵敏度极高的折射率测量办法,在温度、压力传感等方面有 巨大的应用潜力, 但测量精度要求较高。为解决测量的困难和提高古斯-汉兴测量精度,本文设计了一种棱镜 -银纳米膜界面层, 搭建了一套可测量多偏振态多角度古斯-汉兴位移的测量装置,以此测量了棱镜-空气和棱 镜-银纳米膜不同 界面的光束的古斯-汉欣位移,并对其物理机制进行了探讨。实验结果显示棱镜-空气界面 的古斯-汉欣位移 平均值是2.7 μm,棱镜-银纳米膜界面的古斯-汉欣位移平均值是 27.7 μm,比棱镜-空气界面的位移增大了 约10倍。使用COMSOL multiphysics软件模拟了棱镜-银纳米膜以及 棱镜-空气界面的电场分布,对比棱镜- 空气的情况,表明在消逝场作用下,银纳米颗粒表面形成了较强光场分布,光场方向沿入射 光电场振动方 向;银颗粒表面光场和消逝场的叠加使得消逝场增强,从而导致棱镜-银纳米膜界面的古斯 -汉欣位移增大。 本工作为提高基于古斯-汉欣位移效应的生物传感器的灵敏度提供了一个可供选择的手段。     

Formation of uniform and square nanopore arrays on (100) InP surfaces by a two-step etching method

Uniform and square single-crystal InP nanopore arrays have been successfully fabricated on a (100) n-InP surface by a two-step etching method. The characteristic of slow etching rates in four equivalent crystalline (011) facets of (100) n-InP in a mixture of pure HCl and pure H(3)PO(4) has been found, which is the main reason for the formation of square single-crystal InP nanopores. The distribution of nanopores can be closely associated with the distribution of carriers in the semiconductor during the electrochemical etching process. An oscillating behaviour of current has been observed, which can probably be attributed to the oscillations in concentration of the electrolyte at the pore tips caused by diffusion of the electrolyte in the nanopore channels.