Intact soft clay’s critical response to dynamic stress paths on different combinations of principal stress orientation

Comprehensive tests on Hangzhou intact soft clay were performed, which were used to obtain the soils’ critical response to undrained dynamic stress paths under different combinations of principal stress orientation. The different combinations included cyclic principal stress rotation (CPSR for short), cyclic shear with abrupt change of principal stress orientation (CAPSO for short) and cyclic shear with fixed principal stress orientation (CFPSO for short). On one side, under all these stress paths, samples have obvious strain inflection points and shear bands, and the excess pore water pressure is far from the level of initial effective confining pressure at failure. Stress paths of major principal stress orientation (α) alternating from negative and positive have quite different influence on soil’s properties with those in which α is kept negative or positive. On the other side, due to the soil’s strongly initial anisotropy, samples under double-amplitudes CPSR and CAPSO (or single-amplitude CPSR and CFPSO) have similar properties on dynamic shear strength and pore water pressure development tendency when α is kept within ±45°, while have quite different properties when α oversteps ±45°.     

解读连战先生的民族情

文章试图从两方面解读连战先生深厚的民族情.这种民族情一方面来源于他的家族,连战的先祖到台湾死也不臣服清,曾祖父至父亲三代以各种形式坚持抗日及父母对他言传身教;另一方面与他早年在祖国大陆的生活经历有关,从他对抗战和日本的态度及祖国大陆寻踪等方面体现出来.     

Evaluation of ultimate bearing capacity of Y-shaped vibro-pile

Based on Mindlin stress solution, a numerical computational method was proposed to calculate the stresses in the ground induced by side friction and the resistance of Y-shaped vibro-pile. The improved Terzaghi’s and ЪерезанцевВГ’s methods for ultimate bearing capacity evaluation were proposed by considering the stress strength induced by friction resistance at pile head level of Y-pile. A new method to calculate the ultimate bearing capacity of Y-pile was also proposed based on the assumptions of soil failure mode at the tip of Y-pile and the use of Mohr-Coulomb soil yield criterion and Vesic compressive correction coefficient with the induced stresses in the ground. Based on the comparisons with the field static load test results, it is found that the improved Terzaghi’s method gives higher ultimate capacity, while the other two methods shows good agreement with the field results.     

Adhesion coefficient of automobile tire and road surface

The adhesion coefficient of automobile tire and road surface was analyzed and the formula about it was derived.Some suggestions about highway construction,driving safety of the drivers and the judgment of the traffic accidents were presented.The results show that the adhesion coefficient is a function with the extreme value.If there is atmospheric pressure in the tire,the load of the vehicle and the degree of the coarse on the road surface is not selected properly,it will reach the least and affect the safety of the running automobile.     

Effects of stress conditions on rheological properties of granular soil in large triaxial rheology laboratory tests

In order to study the rheological properties of red stone granular soil,a series of rheological experiments were executed on large tri-axial rheological apparatus.Under 100,200 and 300 kPa confining stress conditions,the rheological tests were carried out.These experiment results showed that the stress conditions,especially the stress level were the critical influencing factors of the rheological deformation properties.Under the low stress level(S=0.1),the granular soil showed the elastic properties,and there was no obvious rheological deformation.Under the middle stress level(0.20.8) creep curves showed the non-linear viscous plastic rheological properties.Especially,under the stress level of S=1.0,the accelerated rheological phase of creep curves occurred at early time with a trend of failure.The stress level had obvious effects on the final rheological deformation of the soil sample,and the final rheological deformation increments nonlinearly increased with stress level.The final rheological deformation increment and step was little under low stress level,while it became large under high stress level,which showed the nonlinearly rheological properties of the granular soil.The confining pressure also had direct effects on final rheological deformation,and the final rheological deformation linearly increased with confining pressure increments.     

2008年我国房地产业的发展模式与市场把握

在深入市场调查、认真采集数据和科学分析研究的基础上,从我国新一年房地产业发展的"背景和环境"、"预期和责任"、"风险和影响"、"保障和创新"等方面进行阐述和论证.     

窃取商业秘密获得的专利权归商业秘密权利人所有——兼谈商业秘密构成要件和范围

中国加入WTO以后,知识产权的保护意识日益强化,作为知识产权范畴的专利权更是被人们普遍关注和重视.以"错案"为研究对象,运用商业秘密的有关理论以及保护商业秘密和专利权的有关法律制度,特别是从窃取商业秘密获得的专利权归谁所有的角度,对人民法院的判决进行了分析研究,指出了人民法院的判决是错误的,提出了窃取商业秘密获得的专利权归商业秘密权利人所有.这有利于人民法院公正司法,依法审判.     

从语气助词的角度浅析日语表达方式的特性

日语中有着十分丰富的语气助词,其虽然不具有实际的意义,然而通过语气助词,却能够流露出说话者的心情和感受,传递出不溢于言表的隐性含义,在日常的表达中扮演着十分重要的角色.从语气助词的角度,分析总结日语在表达上所具有的特性.     

Additional water use influencing strength and fluidity of recycled concrete

Through adding different additional water use,the compressive strength,splitting tensile strength and fluidity of recycled concrete of three aggregate combination forms were studied by experiment respectively.The experimental results show that with the increase of adding additional water use,the compressive strength and splitting tensile strength of recycled coarse aggregate concrete decrease,but that of recycled fine aggregate concrete and recycled all aggregate concrete increase firstly then decrease.When additional water use is added more 15% or 20% than that of basic ordinary concrete,the recycled coarse aggregate concrete and fine one can get pretty good fluidity.When it is added more 30%,the recycled all aggregate concrete has fluidity that is just satisfied.     

情趣与意象的契合——《逢雪宿芙蓉山主人》与《雪夜林边驻脚》之比较

通过分析《逢雪宿芙蓉山主人》与《雪夜林边驻脚》两诗的情趣和意象,发现两诗都采用了大致相似的意象.但由于诗人各自的文化传统的差异,在两诗中所传达的情趣却不同.然而,正是由于两诗各自在情趣与意象上的契合,才创造出了各自完美的诗境.     

Effects of CFB Ash on the Adsorption Mechanism of Polycarboxylate Superplasticiser

The effects of circulating fluid bed(CFB) ash on the adsorption performance of polycarboxylate superplasticiser and the mechanism of this influence on the dispersive property of the polycarboxylate superplasticiser were investigated by determing the cement paste fluidity, total organic carbon adsorption, infrared spectroscopic analyses and ζ potential test. The experimental results show that the addition of an inorganic salt into the mixture to change the content of SO_4~(2-)and Fe_2 O_3 can improve the adaptability between the CFB ash and polycarboxylate superplasticiser. Adsorption may occur between the polycarboxylate superplasiciser and Fe_2 O_3, SO_4~(2-)or other components in CFB ash, leading to a significant reduction in paste fluidity. As the content of Na_2 SO_4 in CFB ash reaches 3% or Fe_2 O_3 reaches 9%, the paste loses its liquidity. The organic carbon content in the liquor decreases with an increase in Na2_ SO_4 or Fe_2 O_3 content. Adding some Ba(NO_3)_2 and Na_2 S to the liquor can recover the organic carbon content to a certain extent, and the absolute value of ζ potential will increase. The addition of Ba(-NO_3)_2 or Na_2 S reduces the adsorption property of Na_2 SO_4 or Fe_2 O_3 in CFB ash on the polycarboxylate superplasticiser.     

微波敏化强化芬顿试剂催化氧化NO机理研究

微波结合活性炭的微波敏化方式可大幅提高Fenton试剂氧化能力,为研究产物的生成路径及微波、活性炭、H2O2之间的关联性,自制不同孔隙材料及不同Fe含量的碳材料,采用多组对照实验验证产物O2、CO、NO2的可能生成路径及微波、活性炭的作用,最终得到微波敏化下的芬顿试剂催化氧化NO的反应机理.结果表明:采用活性炭加微波的敏化方式后,NO脱除效率可从33.1%提高至46.3%,O2生成量从6.9%增加到18.6%,同时伴随着体积分数68×10-6的CO生成; O2可通过活性炭的吸附作用及Fe2+的催化作用产生; C及NO只能被芬顿反应过程中生成的·OH、HO2·氧化成CO及NO2;微波可强化体系内所有可发生反应,活性炭能进一步提高微波敏化的前提是发达的孔隙,同时活性炭中存在的部分Fe元素参与到了芬顿反应.     

Study on sulphide capacity of CaO-SiO2-Al2O3-MgO-FetO slags

The sulphide capacity of CaO-SiO2-Al2O3-MgO-FetO slags was studied at 1773 K using gas-slag equilibrium techniques. Utilizing a Pt crucible, the slag was equilibrated with a mixture of gases, namely, CO, CO2, SO2 and N2 to provide the partial pressure of oxygen and sulphur. It was shown that at fixed FetO and Al2O3 contents and a fixed { （?O）＋（%MgO）}/（%SIO2） ratio, the sulphide capacity decreases with increasing MgO content. At a constant （?O）/（%SiO2） ratio and constant MgO and Al2O3 contents, increasing the FetO content of the slags also results in an increase of the sulphide capacity. The rising basicity of （?O）/（%SiO2） from 1.0 to 1.4 at fixed MgO, FetO and Al2O3 contents significantly increases the sulphide capacity.     

Preparation of magnetically separable mesoporous activated carbons from brown coal with Fe_3O_4

Magnetically separable mesoporous activated carbon was prepared from brown coal in the presence of Fe_3O_4 as a bi-functional additive. Magnetic activated carbon(MAC) was characterized by lowtemperature nitrogen adsorption, scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS) and vibrating sample magnetometry(VSM). The evolution behaviors and transition mechanism of Fe_3O_4 during the preparation of MAC were investigated. The results show that prepared MAC with 6 wt% Fe_3O_4 addition having a specific surface area and mesopore ratio of 370 m~2·g~(-1) and 55.7%, which meet the requirements of adsorption application and magnetic recovery. Highly dispersed iron-containing aggregates with the size of 0.1 lm in the MAC were observed. During the preparation of MAC, Fe_3O_4 could enhance the escape of volatiles during the carbonization. Fe_3O_4 could also accelerate burning off the carbon wall during activation, which leads to enlarging micropore size, then resulting in the generation of mesopore and macropore. As a result, a part of Fe_3O_4 converted into FeO, FeOOH, a-Fe, c-Fe, Fe_2 SiO_4 and compound of Aluminum-iron-silicon.The prepared activated carbon, which was magnetized by both of residual Fe_3O_4, reduced a-Fe and cFe, can be easily separated from the original solution by external magnetic field.     

Optical and magnetic properties of Fe<Subscript>2</Subscript>O<Subscript>3</Subscript>/SiO<Subscript>2</Subscript> nano-composite films

Fe₂O₃/SiO₂ nano-composite films were prepared by sol-gel technique combining heat treatment in the range of 100–900 °C. The particle size was observed by FE-SEM. Optical properties of the films were investigated by UV-visible spectra. Structural and magnetic characteristics were investigated through FT-IR and VSM. The transparency of the Fe₂O₃/SiO₂ nano-composite films decreased with the content of the Fe₂O₃. Water and organic solvent in the films were evaporated with heat treatment, so the transparency of the films was enhanced under high temperature. It is also found that the saturation magnetization (M _s) of the films increases with the temperature. As the content of the Fe₂O₃ increases, when the content of the Fe₂O₃ is around 30wt%, the M _s of the films has a maximum value.     

Compression sensibility of magnetic-concentrated fly ash mortar under uniaxial loading

The electrical conductivity, compression sensibility, workability and cost are factors that affect the application of conductive smart materials in civil structures. Consequently, the resistance and compression sensibility of magnetic-concentrated fly ash (MCFA) mortar were investigated using two electrode method, and the difference of compression sensibility between MCFA mortar and carbon fiber reinforced cement (CFRC) under uniaxial loading was studied. Factors affecting the compression sensibility of MCFA mortar, such as MCFA content, loading rate and stress cycles, were analyzed. Results show that fly ash with high content of Fe3O4 can be used to prepare conductive mortar since Fe3O4 is a kind of nonstoichiometric oxide and usually acts as semiconductor. MCFA mortar exhibits the same electrical conductivity to that of CFRC when the content of MCFA is more than 40% by weight of sample. The compression sensibility of mortar is improved with the increase of MCFA content and loading rate. The compression sensibility of MCFA mortar is reversible with the circling of loading. Results show that the application of MCFA in concrete not only provides excellent performances of electrical-functionality and workability, but also reduces the cost of conductive concrete.     

碳钢在上海土壤中的腐蚀行为研究

采用电化学阻抗技术、极化曲线、光学显微镜、能谱仪和X射线衍射等技术,对接地极碳钢材料在上海土壤中的腐蚀电化学行为进行了研究.结果表明:在上海土壤环境中,碳钢的阻抗值随浸泡时间的延长出现先升高再平稳后上升的趋势,腐蚀电流密度降低;碳钢表面形成的腐蚀产物膜,以及阴极氧扩散过程控制的共同作用降低了腐蚀速率;碳钢腐蚀主要以全面腐蚀为主,还伴有微生物腐蚀现象,腐蚀产物膜主要由Fe2O3组成;接地极碳钢材料在上海土壤环境中的耐腐蚀性能为良.     

Adsorption of BSA on carbon-coated Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> microspheres activated with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride

Carbon-coated Fe₃O₄ (Fe₃O₄/C) microspheres activated with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC) were prepared, characterized and applied to adsorb bovine serum albumin (BSA). The prepared magnetic microspheres had spherical core-shell structure with a uniform and continuous carbon coating coupled with activation by EDC, and possessed superparamagnetic characteristics. The experimental results showed that the adsorption amount of BSA on the EDC-activated Fe₃O₄/C (Fe₃O₄/C-EDC) microspheres was higher than that on the Fe₃O₄/C microspheres. The maximum adsorption of BSA on Fe₃O₄/C-EDC microspheres occurred at pH 4.7, which was the isoelectric point of BSA. At low concentrations (below 1.0 M), salt had no noticeable effect on BSA adsorption. The BSA adsorption of Fe₃O₄/C-EDC microspheres had a better fit to the Langmuir model than the Freundlich isotherm and Temkin isotherm model, and the kinetic data were well described by the pseudo-second-order model. The adsorption equilibrium could be reached within 20 min. High desorption efficiency (97.6%) of BSA from Fe₃O₄/C-EDC microspheres was obtained with 0.5 M Na₂HPO₄ (pH 9.4) as the desorbent.     

碳钢电极在Al_2O_3纳米流体中的腐蚀行为研究

采用电化学阻抗谱和极化曲线研究了碳钢电极在以模拟冷却水为基液的Al_2O_3纳米流体中的腐蚀行为.实验结果表明,Al_2O_3纳米颗粒对碳钢的腐蚀有一定的抑制作用;Al_2O_3纳米流体中碳钢电极的耐蚀性能随着温度的升高而降低,添加分散剂十二烷基苯磺酸钠(SDBS)对碳钢也有一定的缓蚀作用,当SDBS的用量超过一定值时,对碳钢的缓蚀性能开始下降.     

Preparation and characterization of superparamagnetic Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>/CNTs nanocomposites dual-drug carrier

Fe₃O₄/carbon nanotubes (Fe₃O₄/CNTs) nanocomposites were prepared by polylol high-temperature decomposition of the precursor ferric chloride and CNTs in liquid triethylene glycol. After surface modification with hexanediamine, folate was covalently linked to the amine group of magnetic Fe₃O₄/CNTs nanocomposites. The products were characterized by Fourier-transform infrared spectroscopy, transmission electron microscopy, and vibrating sample magnetometry. Then Fe₃O₄/CNTs were used as a dual-drug carrier to co-delivery of the hydrophilic drug epirubicin hydrochloride and hydrophobic drug paclitaxel. The results indicated that the Fe₃O₄/CNTs had a favorable release property for epirubicin and paclitaxel, and thus had potential application in tumor-targeted combination chemotherapy.