Impact of Urbanization on Shanghai's Soil Environmental Quality

Heavy metal contents in the soils in the Baoshan District of Shanghai were monitored to evaluate the risk of soil environmental quality degradation due to rapid urbanization and to reveal the ways of heavy metal accumulation in soil during rapid urban sprawl. It was found that the soils in this district were commonly contaminated by Pb, Zn and Cd. Evaluated with a geo-accumulation index (Igeo), the rate of Pb contamination in soils was 100% with 59% of these graded as moderate-severe or severe; Zn contamination reached 59% with 6% graded as moderate-severe or severe; and Cd contamination was over 50%, with one site graded as moderate-severe and another severe-extremely severe. Metal contamination of soils around the Shanghai metropolis was mainly attributed to traffic, industrial production, wastewater irrigation and improper disposal of solid wastes. Because of continuing urbanization, the cultivated land around the metropolis should be comprehensively planned and carefully managed. Also the soil environmental quality of vegetable production bases in this area should be monitored regularly, with vegetables to be grown selected according to the degrees and types of soil contamination.

GURTIN-TYPE VARIATIONAL PRINCIPLES FOR DYNAMICS OF A NON-LOCAL THERMAL EQUILIBRIUM SATURATED POROUS MEDIUM

Based on the porous media theory and by taking into account the efects of the pore fuid viscidity, energy exchanges due to the additional thermal conduction and convection between solid and fuid phases, a mathematical model for the dynamic-thermo-hydro-mechanical coupling of a non-local thermal equilibrium fuid-saturated porous medium, in which the two constituents are assumed to be incompressible and immiscible, is established under the assumption of small de- formation of the solid phase, small velocity of the fuid phase and small temperature changes of the two constituents. The mathematical model of a local thermal equilibrium fuid-saturated porous medium can be obtained directly from the above one. Several Gurtin-type variational principles, especially Hu-Washizu type variational principles, for the initial boundary value problems of dy- namic and quasi-static responses are presented. It should be pointed out that these variational principles can be degenerated easily into the case of isothermal incompressible fuid-saturated elastic porous media, which have been discussed previously.

Genes encoding Pir51,Beclin 1,RbAp48 and aldolase b are up or down-regulated in human primary hepatocellular carcinoma

AIM:To reveal new tumor markers and target genes from differentially expressed genes of primary tumor samples using cDNA microarray.METHODS: The ^33p labeled cDNAs were synthesized by reverse transcription of message RNA from the liver cancerous tissue and adjacent non-cancerous liver tissue from the same patient and used to hybridize to LifeGrid 1.0 cDNA microarray blot containing 8400 known and unique human cDNA gene targets, and an expression profile of genes was produced in one paired human liver tumor tissue.After a global analysis of gene expression of 8400 genes,we selected some genes to confirm the differential expression using Northern blot and RT-PCR.RESULTS:Parallel analysis of the hybridized signals enabled us to get an expression profile of genes in which about 500genes were differentially expressed in the paired liver tumor tissues. We identified 4 genes, the expression of three-(Beclin 1, RbAp48 and Pir51) were increased and one (aldolase b) was decreased in liver tumor tissues. In addition,the expression of these genes in 6 hepatoma cell lines was also showed by RT-PCR analysis.CONCLUSION:cDNA microarray permits a high throughput identification of changes in gene expression. The genes encoding Beclin 1, RbAp48, Pir51 and aldolase b are first reported that may be related with hepatocarcinoma.

Waves induced by a submerged moving dipole in a two-layer fluidof finite depth

The waves induced by a moving dipole in a two-fluid system are analytically and experimentally investigated. The velocity potential of a dipole moving horizontally in the lower layer of a two-layer fluid with finite depth is derived by superposing Greens functions of sources (or sinks). The far-field waves are studied by using the method of stationary phase. The effects of two resulting modes, i.e. the surface- and internal-wave modes, on both the surface divergence field and the interfacial elevation are analyzed. A laboratory study on the internal waves generated by a moving sphere in a two-layer fluid is conducted in a towing tank under the same conditions as in the theoretical approach. The qualitative consistency between the present theory and the laboratory study is examined and confirmed.

Preliminary Study on Nitrogen and Phosphorus Releases from Creek Sediments in Shanghai Suburbs

A laboratory study was conducted to observe the release ofnitrogen and phosphorus from the sediments under both anaerobic andaerobic conditions. The samples used were five creek sediments and afish-pond sediment (as a comparison) obtained from suburban Shanghai.High loads of nitrogen and phosphorus were found in the creeksediments. Total nitrogen of the sediments ranged form 1.17 to 5.95 gkg^-1; total phosphorus from 608.63 to 2 033.95 mg kg^-1. Making upmore than 90/100 of the total nitrogen, organic nitrogen was thedominant nitrogen fraction in the sediments; whereas inorganicphosphorus was the dominant phosphorus fraction, which made up morethan 85 percent of the total phosphorus. Ca-bound phosphorus fractiondominated inorganic phosphorus, which occupied more than 50/100 ofthe total.

Methylation profiling of twenty four genes and the concordant methylation behaviours of nineteen genes that may contribute to hepatocellular carcinogenesis

To determine the possible role of the epigenetic mechanisms in carcinogenesis of the hepatocellular carcinoma, we methylation-profiled the promoter CpG islands of twenty four genes both in HCC tumors and the neighboring non-cancerous tissues of twenty eight patients using the methylation-specific PCR (MSP) method in conjunction with the DNA sequencing. In comparison with the normal liver tissues from the healthy donors, it was found that while remained unmethylated the ABL, CAV, EPO, GATA3, LKB1, NEP, NFL, NIS and p27^(KIP1) genes, varying extents of the HCC specific hypermethylation were found associated with the ABO, AR, CSPG2, cyclin al, DBCCR1, GALR2, IRF7, MGMT, MT1A, MYOD1, OCT6, p57^(KIP2), p73, WT1 genes, and demethylation with the MAGEA1 gene, respectively. Judged by whether the hypermethylated occurred in HCC more frequently than in their neighboring normal tissues, the hypermethylation status of the AR, DBCCR1, IRF7, OCT6, and p73 genes was considered as the event specific to the late stage, while that the rest that lacked such a distinguished contrast, as the event specific to the early stage of HCC carcinogenesis. Among all the clinical pathological parameters tested for the association with, the hypermethylation of the cyclin al gene was more prevalent in the non-cirrhosis group (P=0.021) while the hypermethylated p16^(INK4a) gene was more common in the cirrhosis group (P=0.017). The concordant methylation behaviors of nineteen genes, including the four previously studied and their association with cirrhosis has been evaluated by the best subgroup selection method. The data presented in this report would enable us to shape our understanding of the mechanisms for the HCC specific loss of the epigenetic stability of the genome, as well as the strategy of developing the novel robust methylation based diagnostic and prognostic tools.

A New Elasticity and Finite Element Formulation for Different Young's Modulus When Tension and Compression Loadings

This paper presents a new elasticity and finite element formulation for different Young's modulus when tension and compression loadings in anisotropy media. The case studies, such as anisotropy and isotropy, were investigated. A numerical example was shown to find out the changes of neutral axis at the pure bending beams.

THERMAL ANALYSIS OF FRICTIONAL DISK IN SPEEDING WET CLUTCH

Multi-frictional disks are employed to transmit the torque in speeding wetclutch, and the oil thickness within frictional disks could be adjusted for practical outputspeeding. As oil combined with alpha-hydrocarbon or polyester is getting widely used as lubricantand the speeding wet clutch works within hydrodynamic lubrication, mixture lubrication, boundarylubrication and contact situation, established the thermal analysis model for investigating thebehavior of frictional disks in speeding wet clutch, which covers the power-law fluid model,Patir-Cheng average flow model, GT asperity contact model, oil film inertia and heat effects, meanenergy equation, and heat conduction equation. The formulas in the model are deduced. The numeralcalculation and analysis for hydrodynamic lubrication and mixture lubrication are executed.Relationships and variations among transmitting torque, mean push pressure, output speed, and loadare presented. Thermal effect should be considered during the hydrodynamic lubrication and largertransmitting torque makes earlier entrance to mixture lubrication.

Energy Levels of Strong Coupling Magnetopolaron in Quantum Dot

By using variational method of Pekar type, we have studied the energy levels of strong coupling magnetopolaron in disk shape quantum dot(QD) and quantum well(QW). Our results show that, with the increasing magnetic field and confinement strength, the magnetopolaron binding energy of QD and QW in the ground state and in the excited state is enhanced. The limiting results of bulk type and strict two dimensional type are obtained.

Effect of Aluminum and Silicon on Transformation Induced Plasticity of the TRIP Steel

With the sublattice model, equilibrium compositions of ferrite (a) and austenite (7 ) phases, as well as the volume percent of austenite (7) at 780℃ in different TRIP steels were calculated. Concentration profiles of carbon, Mn, Al and Si in the steels were also estimated under the lattice fixed frame of reference so as to understand the complex mechanical behavior of TRIP steels after different isothermal bainitic transformation treatments. The effect of Si and Mn on transformation induced plasticity (TRIP) was discussed according to thermodynamic and kinetic analyses. It is recognized that Al also induces phase transformation in the steels but its TRIP effect is not as strong as that of Si.

Fission and Fusion of Localized Coherent Structures for a Higher-Order Broer-Kaup System

Starting from a Backlund transformation and taking a special ansatz for the function f, we can obtain a much more generalexpression of solution that includes some variable separated functions for the higher-order Broer-Kaup system. From this expression, we investigate the interactions of localized coherent structures such as the multi-solitonic excitations and find the novel phenomenon that their interactions have non-elastic behavior because the fission/fusion may occur after the interaction of each localized coherent structure.

Applications of Jacobi Elliptic Function Expansion Method for Nonlinear Differential-Difference Equations

The Jacobi elliptic function expansion method is extended to derive the explicit periodic wave solutions for nonlinear differential-difference equations. Three well-known examples are chosen to illustrate the application of the Jacobi elliptic function expansion method. As a result, three types of periodic wave solutions including Jacobi elliptic sine function, Jacobi elliptic cosine function and the third elliptic function solutions are obtained. It is shown that the shock wave solutions and solitary wave solutions can be obtained at their limit condition.

REVIEW AND PROSPECT OF HIGH STRENGTH LOW ALLOY TRIP STEEL

Research status of high strength low alloy TRIP (transformation induced plasticity) steels for automobile structural parts is briefly described. Composition and microstruc-ture factors especially the morphology, size and volume fraction of retained austenite, which largely influence the strength and ductility of the steel, are reviewed and discussed one after another. Modelling of the inter-critical annealing and martempering processes as well as the designing of the TRIP steel aided by commercial software are introduced. Some special aspects of the dynamic mechanical properties of TRIP steel are firstly reported.

Application of nanotechnology in a silver/graphite contact material and optimization of its physical and mechanical properties

By applying nanotechnology, a new type of silver/graphite (AgC) electricalcontact was fabricated and characterized. The AgC coating powders were obtained through high-energyball milling and reducer liquid spraying-coating method. The as-prepared powders were examined bytransmission electron microscope (TEM), scanning electron microscope (SEM), and X-ray diffraction(XRD). The results show that the thickness of graphite flakes milled for 10 h is about 50-60 nm andthe AgC coating powders exhibit flocculent structure with quite fine and homogeneous internalmicropores. XRD implies that the average crystalline size of silver in coating powders is about 50nm. The mechanical and physical properties of this newly developed AgC contact made from theabove-mentioned nanocrystalline powders by traditional powder metallurgy technique were measured.Compared with its counterparts made from other techniques, the properties of this new AgC contacthave been optimized. High surface energy and high-energy interfaces of the nanocrystalline AgCcoating powders provide powerful driving force for sintering densification. Moreover, the flocculentstructure of the powders is also an important factor to acquire fine density ratio.

Red Ratings for Loess-Paleosol Sequences on China’s Loess Plateau and Their Paleo-Climatic Implications

Comparisons of red ratings (RR) with Fe_d, Fe_d/Fet, clay content, andmagnetic susceptibility (x) of two loess-paleosol sequences at Luochuan and Lingtai on China's LoessPlateau were conducted to study the possible relationship between RR and pedogenic degrees of thetwo loess-paleosol sequences, and to discuss whether the RR could become new paleo-climaticindicators. Results showed that the RR of the two loess-paleosol sequences had positive, highlysignificant (P < 0.01) correlations with: 1) citrate-bicarbonate-dithionite (CBD) extracted iron(Fe_d), 2) ratios of CBD extracted iron to total iron (Fe_d/Fet), 3) clay (< 2 mum), and 4) magneticsusceptibility (x). This suggested that the RR of these loess-paleosol sequences could indicatedegreesof loess weathering and pedogenesis and were potential paleo-climatic proxies. The strongcorrelations of RR to Fe_d and x also implied that during pedogenic processes, pedogenic hematite inloess and paleosols were closely related to the amount of total secondary iron oxides and pedogenicferrimagnetic minerals (predominantly maghemite).

Microstructural Evolution of 2.25Cr-1.6W-V-Nb Heat Resistant Steel during Creep

2.25Cr-1.6W-V-Nb developed in Japan, is a low alloy heat resistant steel with good comprehensive properties. Influence of long term creep at elevated temperature on the structure of 2.25Cr-1.6W-V-Nb steel was studied in this paper, and the micromechanism of creep strength degradation was elucidated, too. Both TEM observation and thermodynamic calculation reveal that during creep the transformation occurs from M7C3 and M23C6 to M6C, which can be cavity nucleation sites. Besides, creep at 600癈 also leads to the decrease of dislocation density, the coarsening and coalescence of M23C6, the nucleation of cavities and development of cracks. The strength decrease of 2.25Cr-1.6W-V-Nb steel after long term creep is related to the decrease of dislocation hardening, precipitation hardening, solution hardening, the nucleation of cavities and development of cracks.

Computer Vision-based Navigation and Predefined Track Following Control of a Small Robotic Airship

为小机器的飞艇，飞艇应该能够跟随一条预定义的轨道，这被要求。在这份报纸，计算机为机器的飞艇的基于视觉的航行和最佳的模糊控制策略被建议。第一，视觉航行基于环境的自然里程碑被介绍。例如，当飞艇在一个城市上正在飞时，大楼能被用作其几何性质从数字地图或一个地理信息系统(GIS ) 被知道的视觉烽火。然后，几何方法论被采用关于飞艇的取向和位置提取信息。以便在一个预定义的磁道上保留飞艇，一个模糊飞行控制系统被设计，它把那些数据用作它的输入。并且基因算法(气体) ，一个通用全球优化方法，被利用优化模糊控制器的会员功能。最后，航行和控制策略被验证。

Surface Treatment of Crl2MoV Steel towards Long-Life Cold-Work Dies

With the rapid development of the automobile industry in China, there is an ever-increasing demand for long-life cold working dies used for punching automobile components. However, the full potential of such advanced surface engineering technologies as PVD coatings and duplex surface treatments in cold work dies has not been realized. In the present study, Crl2MoV steel has been surface engineered by single PVD Ti/TiN coating and duplex treatment combining low temperature plasma nitriding (LTPN) with PVD Ti/TiN coatings. The properties of Ti/TiN coatings in terms of surface morphology, microhardness, load bearing capacity, bonding strength and wear resistance were evaluated by microhardness, scratch and wear tests. The experimental results show that PVD Ti/TiN coatings can significantly enhance the surface load bearing capacity (especially for duplex treatments) and wear resistance of Crl2MoV steel by more than one order of magnitude. This can be mainly attributed to the hard and well-adherent PVD Ti/TiN surface coatings and strong mechanical support of the LTPN sublayer. While two-body abrasive wear prevails for uncoated Crl2MoV, the micropolishing action of the counterface dominates in surface engineered material.

CAVITY FORMATION AND ITS VIBRATION FOR A CLASS OF GENERALIZED INCOMPRESSIBLE HYPER-ELASTIC MATERIALS

The problem of radial symmetric motion for a solid sphere composed of a class of generalized incompressible neo-Hookean materials, subjected to a suddenly applied surface tensile dead load, is examined.The analytic solutions for this problem and the motion equation of cavity that describes cavity formation and growth with time are obtained. The e?ect of radial perturbation of the materials on cavity formation and its motion is discussed. The plane of the perturbation parameters of the materials is divided into four regions. The existential conditions and qualitative properties of solutions of the motion equation of the cavity are studied in di?erent parameters’ regions in detail. It is proved that the cavity motion with time is a nonlinear periodic vibration. The vibration center is then determined.

Solitons in a generalized （2＋1）—dimensional Ablowitz—Kaup—Newell—Segur system

In the previous Letter (Zheng C L and Zhang J F 2002 China.Phys.Lett.19 1399),a localized excitation of the generalized Ablowitz-Kaup-Newell Segur(GAKNS) system was obtained via the standard Painlevé truncated expansion and a special variable separation approach. In this work, starting from a new variable separation approach, a more general variable separation excitation of this system is derived. The abundance of the localized coherent soliton excitations like dromions, lumps,rings, peakons and oscillating soliton excitations can be constructed by introducing appropriate lower-dimensional soliton patterns. Meanwhile we discuss two kinds of interactions of solitons. One is the interaction between the travelling peakon type soliton excitations,which is not completely elastic. The other is the interaction between the travelling ring type soliton excitations, which is completely elastic.