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141.
掺入矿渣的水泥土强度模型试验研究及其配方优化 总被引:1,自引:0,他引:1
选取深港西部通道深圳侧接线工程范围内有代表性的淤泥土样,采用均匀设计U20(52×4)安排室内试验,建立了掺入矿渣水泥土的抗压强度回归模型;分析了混合固化剂掺入比、矿渣占固化剂的质量比和龄期及其交互作用对抗压强度的影响;模型预测值和室内平行试验的对比分析表明:该模型具有一定的可信度。模型表明矿渣占混合固化剂的质量比在一定区间内(40%~70%)对水泥土强度的增强效果显著,这与工程实践相吻合;为确定优化配比,建立了求解用多目标优化函数。考虑到现场条件与室内试验的差别,建立了12组相同配比的室内试块及现场搅拌桩对比试验,结果表明:现场搅拌桩的水泥土无侧限强度远低于室内水泥土试块强度,矿渣的增强作用与室内试验各龄期基本一致。 相似文献
142.
143.
GDX-502树脂富集高效液相色谱法测定地表水中酚类化合物 总被引:2,自引:2,他引:2
采用自制GDX-502固相萃取小柱萃取水中苯酚、对硝基酚、间甲酚、2,4-二氯酚、2,4,6-三氯酚、五氯酚等6种酚类化合物,以乙腈作为洗脱剂,选择280nm和290nm双波长紫外高效液相色谱进行检测。结果表明,方法检出限为0.01-0.05mg/L,IL水的平均加标回收率为82.5%-95.0%,精密度(RSD,n=7)为3.6%-9.2%。方法用于实际地表水中痕量酚类化合物的检测,操作简单,有机溶剂用量少,分析效率高;萃取小柱可多次重复使用,分析成本低。 相似文献
144.
电解锰压滤渣是工业生产金属锰过程中采用湿法酸浸电解工艺产生的一种工业废渣。这种传统的废渣处理处置方式,极易造成严重的环境污染和地质灾害的发生。本次研究将电解锰压滤渣通过焙烧生产活性微粉、产生的脱硫烟气制硫酸,是一种能有效解决电解锰压滤渣处理处置和综合利用的方法。本文对"锰三角"地区拟建20万吨电解锰压滤渣焙烧生产活性微粉、脱硫烟气制硫酸生产示范线项目,进行了区域市场调研,对项目的经济效益与社会效益进行分析。该项目年均可实现销售收入4162.7万元,为当地循环经济和锰产业可持续发展探索了一条新的出路。 相似文献
145.
André F. Lotter H. John B. Birks Wolfgang Hofmann Aldo Marchetto 《Journal of Paleolimnology》1998,19(4):443-463
Surface sediments from 68 small lakes in the Alps and 9 well-dated sediment core samples that cover a gradient of total phosphorus (TP) concentrations of 6 to 520 g TP l-1 were studied for diatom, chrysophyte cyst, cladocera, and chironomid assemblages. Inference models for mean circulation log10 TP were developed for diatoms, chironomids, and benthic cladocera using weighted-averaging partial least squares. After screening for outliers, the final transfer functions have coefficients of determination (r2, as assessed by cross-validation, of 0.79 (diatoms), 0.68 (chironomids), and 0.49 (benthic cladocera). Planktonic cladocera and chrysophytes show very weak relationships to TP and no TP inference models were developed for these biota. Diatoms showed the best relationship with TP, whereas the other biota all have large secondary gradients, suggesting that variables other than TP have a strong influence on their composition and abundance. Comparison with other diatom – TP inference models shows that our model has high predictive power and a low root mean squared error of prediction, as assessed by cross-validation. 相似文献
146.
A three-dimensional, three-phase numerical model is presented for simulating the movement of immiscible fluids, including
nonaqueous-phase liquids (NAPLs), through porous media. The model is designed to simulate soil flume experiments and for practical
application to a wide variety of contamination scenarios involving light or dense NAPLs in heterogeneous subsurface systems.
The model is derived for the three-phase flow of water, NAPL, and air in porous media. The basic governing equations are based
upon the mass conservation of the constitutents within the phases. The descretization chosen to transform the governing equations
into the approximating equations, although logically regular, is very general. The approximating equations are a set of simultaneous
coupled nonlinear equations which are solved by the Newton-Raphson method. The linear system solutions needed for the Newton-Raphson
method are obtained using a matrix of preconditioner/accelerator iterative methods.
Because of the special way the governing equations are implemented, the model is capable of simulating many of the phenomena
considered necessary for the sucessful simulation of field problems including entry pressure phenomena, entrapment, and preferential
flow paths. The model is verified by comparing it with several exact analytic test solutions and three soil flume experiments
involving the introduction and movement of light nonaqueous-phase liquid (LNAPL) or dense nonaqueous-phase liquid (DNAPL)
in heterogeneous sand containing a watertable.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
147.
NUMERICAL STUDY OF REMOTE SENSING OF CLOUD LIQUID WATER CONTENT BY SPACE-BORNE COMBINED RADAR-RADIOMETER 总被引:1,自引:0,他引:1
A retrieval method of microwave(MW)space-borne remote sensing of cloud liquid watercontent by the combined radar-radiometer is suggested.A three-layer cloud model is chosen torepresent the typical stratified precipitating cloud.The retrieval method mainly follows ourpreviously suggested scheme with some modifications.Numerical comparative study shows that inspace-borne remote sensing of cloud liquid water content by the combined method is much betterthan by radar only;Also the retrieval accuracy of cloud liquid water content may be improvedwhen using the three-layer cloud model in the combined method. 相似文献
148.
针对日常生活中因对温度变化的忽视引起的各种问题,提出一种对温度进行远程监测并短信通知用户的系统,以达到向用户进行温度报警的目的.系统主要由STC89C52单片机,液晶显示器1602,温度传感器DS18B20,TC35模块4大部分构成,首先通过温度传感器DS18B20采集当前环境温度,然后利用液晶显示器1602将当前温度显示出来,与此同时单片机判断当前温度值,当前温度超过温度上限值时,单片机控制GSM模块向指定手机号发送一条短信.结果显示,当温度超过设定温度时,指定手机会收到一条报警短信,提醒用户当前的温度超过了温度上限.通过与传统的温度检测系统作对比,系统能够得到较准确的温度检测值其测温误差能够控制在0.4以下,并且通过发送短信来对温度进行远程实时监测. 相似文献
149.
黄东海表层沉积物中磷的赋存形态和分布特征及其对生态系统的潜在影响 总被引:2,自引:0,他引:2
For better understanding the phosphorus(P) cycle and its impacts on one of the most important fishing grounds and pressures on the marine ecosystem in the Yellow Sea(YS) and East China Sea(ECS), it is essential to distinguish the contents of different P speciation in sediments and have the knowledge of its distribution and bioavailability. In this study, the modified SEDEX procedure was employed to quantify the different forms of P in sediments. The contents of phosphorus fractions in surface sediments were 0.20–0.89 μmol/g for exchangeable-P(Exch-P), 0.37–2.86 μmol/g for Fe-bound P(Fe-P), 0.61–3.07 μmol/g for authigenic Ca-P(ACa-P), 6.39–13.73μmol/g for detrital-P(DAP) and 0.54–10.06 μmol/g for organic P(OP). The distribution of Exch-P, Fe-P and OP seemed to be similar. The concentrations of Exch-P, Fe-P and OP were slightly higher in the Yellow Sea than that in the East China Sea, and low concentrations could be observed in the middle part of the ECS and southwest off Cheju Island. The distribution of ACa-P was different from those of Exch-P, Fe-P and OP. DAP was the major fraction of sedimentary P in the research region. The sum of Exch-P, Fe-P and OP may be thought to be potentially bioavailable P in the research region. The percentage of bioavailable P in TP ranged from 13% to 61%. Bioavailable P burial flux that appeared regional differences was affected by sedimentation rates, porosity and bioavailable P content, and the distribution of bioavailable P burial flux were almost the same as that of TP burial flux. 相似文献
150.
初步研究了在海参养殖池塘中,不同养殖方式下,大型海藻海黍子(Sargassum muticum)的生长特性及对水体中氨氮和活性磷的去除作用。2012年3~5月,在山东莱州试验养殖海黍子60d,结果发现其长度最大从43.8cm增长到81.3cm,增长85.6%,日增长率(SGR)在14℃时最大,达到5.0%;每绳的平均质量从0.74kg增到2.59kg,增长3.5倍,SGR在12℃时最大,达4.3%;水体氨氮平均下降了25.9%,活性磷下降了37.5%。实验证明海黍子能在适合的池塘中养殖,并且能有效的去除水体中的氨氮和活性磷,是有效的近海生境修复大型工具种海藻。 相似文献