高压旋喷扩底桩在桥台软土路基中的应用分析

针对某高速公路桥台软土路基工程地质情况,对高压旋喷注浆设计程序、扩底桩选型、设计桩长确定与设计计算方法进行了探讨,其中设计计算主要包括承载力与沉降计算。并介绍了高压旋喷扩底桩施工工艺及施工质量控制措施。     

Electrogenerated chemiluminescence sensor for the determination of metoclopramide using ordered mesoporous carbon for immobilizing tris(2, 2'-bipyridyl) ruthenium

A novel electrogenerated chemiluminescence (ECL) sensor for the determination of metoclopramide was developed by employing ruthenium complex as an ECL signal producer and an ordered mesoporous carbon (OMC) material as modified material. The ECL sensor was fabricated by adsorption ruthenium complex into a mixture of OMC and Nafion, which showed good electrochemical and ECL behaviors. It was found that the ECL intensity of the sensor fabricated was greatly enhanced in the presence of metoclopramide. Based on this finding, a highly sensitive and reproducible ECL method was developed for the determination of metoclopramide. The result showed that the ECL intensity was linear with the concentration of metoclopramide in the range from 1.0×10-10 to 5.0×10-7M and the detection limit was 3×10-11M. The ECL sensor exhibited a long-term stability and a fine reproducibility with relative standard deviation of 1.0 % for 1.0×10-10M metoclopramide in 18 continuous determinations. The developed method has been applied to the determination of metoclopramide in tablet samples with satisfactory results.     

Duffing系统对称破缺分岔及其逆分岔研究

研究了Duffing系统中作为倍周期分岔前兆的对称破缺分岔及其机理,Lyapunov指数与对称破缺分岔之间的关系．研究表明对称破缺分岔意味着仅含奇次谐波周期解的失稳和稳定的含有奇、偶次谐波周期解的出现,而且在此临界稳定点应有最大Lyapunov指数等于零．通过数值计算发现,在达到倍周期分岔前最大Lyapunov指数经历了3个零点,对应于系统的两次对称破缺分岔和一次逆对称破缺分岔,并确定了分岔点的,值。     

Transverse Vibration of Train-Bridge and Train-Track Time Varying System and the Theory of Random Energy Analysis for Train Derailment

Summary In this paper, the fundamental problems in the calculation of transverse vibration of train-bridge and train-track time-varying system (hereinafter referred to as the system) are expounded. That is, (1) Proper solution to transverse vibration of the system cannot be obtained by establishing separate transverse vibration equation groups for the car and the bridge (or track); (2) The exciting source of transverse vibration of the system has not been made definite; (3) It is difficult to carry out the random analysis of vibration of the time varying system as the theory of the random vibration analysis for the time varying system has not been established. Our thinking and methods to solve these problems are introduced. On the above-mentioned basis, the theory of random energy analysis for train derailment is presented. The main contents of this theory are as follows: method of random energy analysis of transverse vibration of the system; geometric criterion of derailment; mechanism of derailment caused by the combined track irregularity and energy increment criterion for derailment evaluation; calculation of the entire derailing process; method of improvement of track parameters for preventing straight line speed-raise freight trains from derailment and of the calculation of the safety coefficient against derailment. This theory is used to calculate a case of freight train derailment, which corresponds to an actually occurred accident. A train in another derailment test is judged to be not derailed and its maximum vibration responses are calculated. The field test results are well responded.     

Influence of Pit Foundation Excavation on an Adjacent Metro北大核心CSCD

With the development of urban metro systems, the influence of foundation pit construction on metro fa-cilities and related protection measures are getting more and more attention. A technical program for metro assess-ment at different phases of foundation pit construction is proposed using the statistics and analysis of a foundation pit of the Hangzhou metro. Qualitative and quantitative methods for analyzing the influence that foundation pit exca-vation has on metro systems are studied, and a series of protective measures suitable for foundation pit construction are summarized. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

3500吨客货船的舱室噪声分析及计算

本文初步介绍了舱室噪声的成因,然后对我院设计的3500吨客货船进行分析、研究,并介绍了我们为降低舱室噪声采取的一系列措施。最后,列出了3500吨客货船的舱室噪声计算结果及实测结果。     

水泥搅拌桩在天津沿海软基加固中的应用

水泥搅拌桩在软土地基加固工程中应用非常广泛，但在不同地质条件下其设计参数和施工工艺不同，结合天津市重点工程天津碱厂搬迁改造及华能绿色煤电IGCC电站铁路专用线工程对水泥搅拌桩的设计参数和施工工艺进行了现场试验，取得了合理的施工方案，对类似工程有较好的参考价值。     

大断面隧道工程补充单价分析编制方法的探讨

随着高速铁路、客运专线建设被提上议事日程，目前铁路建设标准不断提高，隧道断面随铁路速度目标值的提高而增大。现行隧道单、双线定额已不适用于新隧道结构，需尽快颁布出台大断面隧道定额。此针对大断面隧道工程在暂无定额可用的情况下，对大断面隧道工程补充分析编制方法进行探讨和分析。     

Comparison of trends in tributyltin concentrations among three monitoring programs in the United States

The results of three national monitoring programs in the United States (U.S.) that measure concentrations of tributyltin (TBT) are compared. Regional and site comparisons are made of changes in TBT concentrations since passage of the Organotin Antifouling Paint Control Act (OAPCA) in 1988. The monitoring programs compared are the U.S. LongTerm Monitoring Program conducted by a consortium of tributyltin manufacturers, the National Oceanic and Atmospheric Administration's National Status and Trends Mussel Watch project, and the U.S. Navy's TBT monitoring program. All of the monitoring results demonstrate declining TBT concentrations over time. These declines have occurred rapidly (within a few years) and are considerable (56%–71% decrease in TBT concentrations in water, 47%–55% decrease in sediments, and 40%–82% decrease in bivalve tissues). Mean TBT concentrations in water are generally below the current U.S. Environmental Protection Agency marine chronic water quality criterion of 10ng/L. These results indicate that the OAPCA has been effective in reducing TBT concentrations in the aquatic environment.     

帕萨特柴油出租车燃用天然气制油的路试排放特性研究

对燃用天然气制油(简称GTL燃油)和国Ⅲ柴油的帕萨特柴油出租车整车路试排放进行了研究。结果表明,帕萨特柴油出租车燃用GTL燃油和国Ⅲ柴油完全满足国Ⅲ排放限值要求;与燃用国Ⅲ柴油比较,在10万km的行驶里程中,燃用GTL燃油车辆的CO、PM、HC NOx、NOx和CO2排放的平均值分别下降了48.6%、36.7%、9.4%、9.0%和3.2%,即GTL燃油的排放性能明显改善;天然气制油是柴油的良好替代清洁燃料之一。