碎石桩复合地基承载力计算探讨

碎石桩是一种散体材料桩,在石油化工储罐工程中广泛使用,是一种经济有效的地基处理方法。目前碎石桩有多种成桩方法,如振冲碎石桩、振动沉管碎石桩、柱锤冲扩碎石桩等。本文对确定碎石桩复合地基承载力的7种方法从基本假设、计算模型、计算参数、计算公式等方面进行探讨,通过工程实例,将7种计算方法的计算结果与实验结果进行了对比。     

地基处理方案的优化研究

本文以新疆某工程地基处理方案为研究对象,结合工程所在地类似工程经验,对振冲碎石桩、换填法和CFG粉煤灰碎石桩三种地基方案进行了对比分析。运用了技术经济比较的综合评判方法,结合上部建筑和基础型式对地基承载力的需求,对三种地基方案进行优化研究,得出振冲碎石桩为最优的结论,对类似工程有借鉴意义。     

水泥粉煤灰碎石桩复合地基在实际应用中的问题

水泥粉煤灰碎石桩(CFG桩)复合地基自应用以来,逐渐代替了部分原有的人工挖孔桩及钻孔灌注桩桩基础,大大降低了工程造价,同时也节省了工期,产生了较大的经济及社会效益。然而随着应用越来越广,实际应用中出现的问题也越来越多,给工程带来不小的安全隐患。文章在设计、施工及检测等三个方面对水泥粉煤灰碎石桩(CFG桩)复合地基在实际工程中的应用进行了分析总结,阐述了水泥粉煤灰碎石桩(CFG桩)复合地基在实际应用中存在的一些问题。     

高地震烈度区严重液化场地地基处理应用研究

高地震烈度区严重液化场地的地基处理一直是工程界面临的难题。国外某工程位于地震烈度Ⅷ度区,严重液化场地,液化最深处至14.7m。本文针对该工程,对多种液化处理方法(预制桩、无填料振冲、振冲碎石桩)进行对比分析,得出针对该工程建(构)筑物最适用的地基处理方案为振冲碎石桩方案。接着结合实际工程对振冲碎石桩设计过程中的关于桩长、试验性施工等几个关键问题进行探讨总结,提出几点自己的感悟,以期对类似工程有一定的参考价值。     

振冲碎石桩复合地基在小龙高速公路工程中的应用

本文结合振冲碎石桩在小龙高速公路工程中的应用,主要介绍了振冲碎石桩技术在提高高速公路红黏土路基的承载力和稳定性方面的原理和工作方法。     

RJP工法桩与高压旋喷桩组合施工在碎石地层中的应用

RJP工法桩具有施工深度大、成桩直径大、成桩效果好的特点,但在碎石层中不易成桩施工,在地质条件为碎石层及杂填土层施工RJP桩时,采用先高压旋喷桩稳定土体,再引孔施工RJP桩的组合方法是切实可行的,为以后类似工程提供了借鉴。     

振动沉管挤密碎石桩在中石化储油罐地基处理中的应用

现代科学技术的进步带动工程建设事业的进步,随着环保意识的提高,挤密碎石桩因其工期短、经济、无污染、减少地基的沉降量、提高复合地基承载力等特点,在油罐、水池等各类工程得到了广泛的运用。本文以福建泉港油库/首站振动沉管挤密碎石桩工程为实例,对振动沉管挤密碎石桩在中石化储油罐地基处理中的应用进行了探讨。     

水泥粉煤灰碎石桩复合地基承载性能分析

水泥粉煤灰碎石桩是复合地基施工中的常用方法,可以有效提高复合地基的承载能力。基于此,以宁夏银川市某商业住宅楼工程的水泥粉煤灰碎石桩复合地基为背景,建立了FLAC 3D数值计算模型,分析了水泥粉煤灰碎石桩和不同结构荷载对复合地基的变形破坏特征的影响规律。研究结果表明:设置水泥粉煤灰碎石桩有效降低了地基土体的最大沉降、水平位移、最大竖向应力和塑性区范围,保证上方建筑的施工和使用要求;随上方筏板基础所受荷载的增大,复合地基的地表最大沉降值、水平位移值、塑性区增大,碎石桩的竖向应力增大,复合地基的竖向应力无显著变化。     

土工合成材料约束碎石桩承载特性研究

土工合成材料作为新型的软土地基处理技术,在工程领域大量应用。但是土工合成材料的种类和规格很多,材料的性能也有所不同,所以需要建立可计算出各种土工合成材料所受载荷的方法模型。土工合成材料的单桩承载力由材料的抗拉强度和工程性质决定,考虑将土工材料和碎石桩的相互作用作为已知变量,以及碎石桩所承受的上部载荷,就可以推导出土工合成材料所受到的约束拉力与所在土体围压的桩身强度的关系。通过莫尔-库仑理论和布西内斯克理论推导得到了土工合成材料受的约束拉力沿深度的分布,为土工合成材料碎石桩的设计提供计算依据。     

软塑黄土隧道基底浆固碎石桩加固技术研究

针对大断面软塑黄土地层隧道基底含水率高、强度低、自稳能力差、施工风险高、危害大,极易发生施工灾害的问题,以新建银川至西安铁路甘宁段站前工程YXZQ-2标段上阁村隧道为依托背景,首次将浆固碎石桩应用于处理黄土隧道基底软塑土,通过对浆固碎石桩进行室内外试验、施工工艺、施工机械、检测方法等方面进行深入研究,形成了浆固碎石桩在黄土隧道软塑地基条件下的加固方法,并设置测试元器件对加固效果进行了验证。研究表明,浆固碎石桩作为一种新型桩基,在黄土隧道软土地基加固方面有其特殊优点,加固效果好,质量可靠,处理深度大,可进一步推广应用。     

小鼠神经生长因子基因治疗型DNA质粒的质量控制

目的对小鼠神经生长因子(NGF)基因治疗型DNA质粒进行质量控制。方法用酶切鉴定法和PCR法进行DNA质粒的结构确认,鸡胚背根神经节法和免疫印迹测定DNA质粒表达产物的生物学活性,分光光度法测定浓度,琼脂糖凝胶电泳法和DNA-NPR-HPLC法测定纯度,气相色谱法测定乙醇和异丙醇残留量,琼脂糖凝胶电泳法测定RNA残留量,其余检测项目按《中国药典》三部(2005版)规定进行。结果用上述方法对原液和成品进行了检定,各项指标均符合《预防用DNA疫苗临床前研究技术指导原则》和《中国药典》三部(2005版)的要求。结论所采用的质控方法和质量标准能够保证该DNA质粒的安全、有效,可用于治疗型DNA质粒的质控。     

The formation of carbon nanotube dispersions by high pressure homogenization and their rapid characterization by analytical centrifuge

Dispersion of carbon nanotubes (CNTs) in a liquid medium requires separation of the bundles, a process which is usually achieved by sonication for prolonged time, and is suitable for low sample volumes. A rapid and simple process for producing dispersions of multi-wall carbon nanotubes (MWCNTs) was developed, by using a high pressure homogenization process (HPH). Dispersions of MWCNTs were prepared in aqueous solutions containing ethoxylated octyl phenol, and were compared to dispersions prepared by the conventional sonication method. They were evaluated by rapid measurement of sedimentation rate during centrifugation, and results compared to other evaluation methods. It was found that samples processed by HPH for a short time yielded similar dispersions to those obtained by sonication for prolonged time, and that the first pass through the homogenizer, which takes less than a minute, is the most significant in breaking up the bundle. The process can be used in a continuous mode for large volumes, and is very suitable for large-scale industrial production. Evaluation of the CNT dispersions by centrifugal sedimentation analysis correlates well with other time-consuming methods.     

不同交联方法制备的人表皮生长因子凝胶微球的性能比较

目的比较不同交联方法制备的人表皮生长因子(Humanepid ermal growth factor,hEGF)凝胶微球的体外性能。方法采用化学交联、光交联和热交联方法,制备复合hEGF凝胶微球,观察其形态,测定其粒径、质量残留率、载药率和包裹率,并采用ELISA法检测hEGF的体外释放效果。结果 3种方法制备的凝胶微球的形态、粒径、载药率和包裹率均无显著差异;但化学交联法制备的微球释药时间明显较光交联和热交联法制备的微球长,降解速度较光交联和热交联法制备的微球慢。结论化学交联法制备的hEGF凝胶微球性能好,具有作为缓释生长因子载体的应用前景。     

Investigation of cellulose convertibility and ethanolic fermentation of sugarcane bagasse pretreated by wet oxidation and steam explosion

Sugarcane bagasse was pretreated by wet oxidation (WO) at 195 °C for 15 min under either alkaline, neutral or acidic conditions, and by steam explosion (STEX) at 205 °C for 10 min. Alkaline WO was more favourable than neutral and acidic WO for the following enzymatic hydrolysis of cellulose, giving 792 g kg^?1 glucose yield after 48 h. The enzymatic hydrolysis of the fibres in the whole slurry was inhibited by inhibitory compounds contained in the prehydrolysate in comparison with the hydrolysis of the washed solid fibres in buffer. The inhibition increased proportionally with formic acid concentration in the pretreated liquid fraction. Cellulose conversion was higher for simultaneous saccharification and fermentation (SSF) than for separate hydrolysis. The highest SSF conversion (829 g kg^?1) was obtained for the material treated by alkaline WO. The fermentability of the prehydrolysates by Saccharomyces cerevisiae was evaluated. Stronger inhibition of ethanolic fermentation was observed in the prehydrolysate obtained by steam explosion. The inhibition was more noticeable for the volumetric productivity than for the ethanol yield. The volumetric productivity was reduced by 94.5 and 91.2% for STEX and WO, respectively, whereas the ethanol yield was reduced only by 45.2 and 31.0%, correspondingly, for STEX and WO. Furan aldehydes seemed to be mainly responsible for the inhibition of the fermentation. Copyright © 2006 Society of Chemical Industry     

狂犬病病毒核衣壳抗原诊断试剂盒实验室内的质控方法

目的探讨狂犬病病毒核衣壳抗原诊断试剂盒实验室内质控方法。方法以ELISA双抗体夹心法检测狂犬病病毒抗原为例,采用“Levey-Jennings”和“即刻法”质控法进行对比。结果“Levey-Jennings”质控图中所有测定结果均处于“在控状态”,而“即刻法”质控图中一次测定结果处于“失控状态”。结论宜采用双质控方法进行狂犬病病毒核衣壳抗原诊断试剂盒实验室内质控。     

重组铜绿假单胞菌外毒素A工程菌发酵及表达产物的纯化

目的建立稳定、高效表达重组铜绿假单胞菌外毒素A(rEPA)的工程菌发酵及表达产物纯化工艺。方法规模化发酵表达rEPA的重组大肠杆菌rPE553D,离心收集菌体,渗透压调解使菌体周质间隙蛋白释放后,高速离心收集蛋白溶液。经DEAESepharoseFF、PhenylSepharose6FF疏水层析和SOURCE30Q强离子交换层析,超滤浓缩纯化rEPA。用HPLC、SDS-PAGE和Westernblot等方法检定生化和免疫学特性,并用小鼠和Vero细胞检定毒性。结果每55L培养基中rEPA产量超过4g,纯度在95%以上,细胞毒性降低了至少32000倍。其余各项指标均符合《中国生物制品规程》要求。结论已建立了收率高、纯度好、稳定、适合规模化生产rEPA的工艺。     

工业聚合反应装置：Ⅷ.聚烯烃装置

简介了低密度聚乙烯、高密度聚乙烯和聚丙烯生产工艺及其聚合反应器。     

抗氧化低密度脂蛋白单克隆抗体制备方法的研究

目的研究抗氧化低密度脂蛋白(OxLDL)单克隆抗体的制备方法。方法采用小鼠体内法制备抗OxLDL单克隆抗体时,腹水中抗体经SuperoseTM6 HR10/30凝胶柱进行一步纯化;采用细胞培养法时,分别对杂交瘤细胞生长特性和抗体表达条件进行研究,细胞培养上清中抗体经Streamline SPXL阳离子扩张柱床层析和QXL阴离子交换层析纯化。结果小鼠体内法制备的抗体纯度为95.7%,回收率为65.4%;细胞培养上清中得到的抗体纯度为94.7%,回收率为47.8%。结论已建立了2种抗OxLDL单克隆抗体的制备方法,为OxLDL酶联免疫检测试剂盒的研制奠定了基础。     

3-amino-1-propanol as a complexing agent in the determination of total gossypol

Summary A method is proposed for the determination of total gossypol in cottonseed meals, crude oils, and soapstocks based on a rapid extraction of gossypol by neutralized 3-amino-1-propanol in dimethylformamide to form a stable complex, followed by colorimetric analysis of an aliquot of the extract by means of an aniline reaction. A determination can be completed in about 2 hrs. and with minor modification in 1 hr. compared to about 7 hrs. for current methods. Results obtained by the proposed procedure on meals, oils, and soapstocks are in essential agreement with those found by use of other accepted methods. Desirable features, such as stability of reagents and extracts and a high degree of reproducibility, suggest that the procedure will satisfy the requirements for a rapid and simplified method for the analysis of all cottonseed products for total gossypol. One of the laboratories of the Southern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.     

Über die Abtrennung von n-Paraffinen durch Harnstoffaddukt-Bildung

Separation of n-Paraffins by Urea-Adduct Formation Using various procedures for the formation of urea adducts, the determination of n-paraffins in products (solidification point 25°–64°C) containing low, moderate and high concentration of these substances is reported. Theses results are compared with values that are obtained by molecular sieve and antimony pentachloride methods. The authors have established that the determination of n-paraffin by the urea method, as reported in the literature by numerous authors, provides approximate values. The results of the present work indicate that the experimental conditions that are to be employed for the determination of paraffin content by urea-adduct formation, must be adjusted for each type of product after comparing the results obtained by the molecular sieve method. The possibility for the determination of n-paraffins in other petroleum fractions by urea method is discussed.