The U/Ω effect of electricity parameters of the lotus root silk in the liquor with different pH values

The silk of lotus root is a kind of natural biomaterial with the advantages of easy absorbing and dis-solving and poisonless. It may become a new engineering material for clinic and tissue engineering. However, the relationship between its electricity parameters and the pH values of the liquor that the silk is dipped in is unknown presently. The electricity parameters of inductance, capacitance and imped-ance of the silk were measured in the environment with the temperature ranging from 23℃ to 25℃ and the humidity ranging from 45% to 55% when it was dipped in the liquor with different pH values for 24 h. The results show that the inductance and impedance vary in U shape curves with the liquor pH value, and the capacitance varies in Ω shape curve. The minimal value of the U curves and the maximal value of the Ω curve appear at the point where the pH value equals to 7. The phenomena are called the U/Ω effect. It means that the silk has perfect biocompatibility with human tissues. The study results may imply that the silk have broader potential applications in biomedicine, tissue engineering and bioelec-tronics. silk of lotus root, biomedicine engineering material, U/Ω effect, pH value of liquor     

Study on Luster of Fabrics with Goniophotometric Curves

The distribution of the light reflected from various fabric surfaces was studied. A series of samples of different fibers, weaves and colors were investigated. The experiments show that the goniophotometric curves of fabrics change with constituent fibers, weave, dyeing and finishing, and experimental condition. The goniophotometric curves for fabrics of same kind with different colors are same in general shape, and the reflectance or the height of the curves are changed to the extent of that they are in proportion with the brightness or the tristimulus value Y of the samples. The goniophotometric curve also varies in form when the incident angle is changed. Discussion and explanation for the above mentioned are given. Luster of the samples was calculated with methods suggested by different indexing systems.     

Measurement of Magnetization Curve and Magnetic Relaxation for 2H-NbSe2 Crystals

The characteristics of electronic transport properties: behaviors of magnetization curve and magnetic relaxation of a typical normal superconductor 2H-NbSe2 are investigated. The results show that Tc and △Tc of the samples are 7. 2,0. 18 K, indicating that superconducting energy gap at zero temperature is 1. 1 meV. No fish tail shape is found in the magnetization curves at several temperatures. The relationship between remnant magnetic moment and time reveals that the magnetic flux creep of the sample agrees with the Kim-Anderson thermal activation model with the relaxation rate S=0.000 36 at T=6 K.     

The Influence of Transmutation Conditions on the Adulteration Performance of Nano—scale Nickel Hydroxide

Spherical Nano-scale nickel hydroxide was prepared through precipitaition transmutation method by controlling the transmutation conditions in this paper.The measurement results of XRD and TEM indicate that the crystallization of the nano-Scale nickel hydroxide is β-style and its shape is spherical with a diameter of 40-70 nanometer.The adulteration experiment shows that the adulteration ratio of nono-scale Ni(OH)2 in common spherical micrometer-scale Ni(OH)2 exists a optimal value(1:9) And at this point,the utilization ratio of Ni(OH)2 in electrodes can be raised by 10%,and the nono-Scale nickel hydroxide with sphericity shape shows a better adulteration performance than that with needle shapge.     

A new method for automatically constructing convexity-preserving interpolatory splines

Constructing a convexity-preserving interpolating curve according to the given planar data points is a problem to be solved in computer aided geometric design (CAGD). So far, almost all methods must solve a system of equations or recur to a complicated iterative process, and most of them can only generate some function-form convexity-preserving interpolating curves which are unaccommodated with the parametric curves, commonly used in CAGD systems. In order to overcome these drawbacks, this paper proposes a new method that can automatically generate some parametric convexity-preserving polynomial interpolating curves but dispensing with solving any system of equations or going at any iterative computation. The main idea is to construct a family of interpolating spline curves first with the shape parameter a as its family parameter; then, using the positive conditions of Bernstein polynomial to respectively find a range in which the shape parameter a takes its value for two cases of global convex data points and piecewise convex data points so as to make the corresponding interpolating curves convexity-preserving and C2(or G1) continuous. The method is simple and convenient, and the resulting interpolating curves possess smooth distribution of curvature. Numerical examples illustrate the correctness and the validity of theoretical reasoning.     

Approximate merging of multiple Bézier segments

This paper deals with the approximate merging problem of multiple adjacent Bézier curves with different degrees by a single Bézier curve, which is a frequently seen problem in modeling. The unified matrix representation for precise merging is presented and the approximate merging curve is further derived based on matrix operation. Continuity at the endpoints of curves is also discussed in the merging process. Examples show that the method in this paper achieves satisfying merging results.     

Shape controllable preparations of PbS nanocrystals using cysteine as the precursor of S^2- ions

Flowerlike, spherical and cubic PbS nanoparticles have been successfully synthesized by refluxing cysteine and lead nitrate in an alkaline solu- tion. The influences of the cysteine to Pb2 molar ratio, the pH value of the reaction mixture as well as the refluxing time on the shape of PbS nanoparticles were investigated. Detailed experimental results demonstrated that a higher molar ratio of cysteine to Pb2 (5.2:1) and shorter refluxing time favor the for- mation of flowerlike PbS nanoparticles at pH 9.0. While lower pH value (8.0) favors the formation of spherical PbS nanoparticles, and higher pH value (10.0), however, favors the formation of cubic PbS nanoparticles. The mechanism for the shape control of PbS nanoparticles is discussed.     

Molecular architecture and engineering of spider dragline silk protein

Spider dragline silk, which is produced in spider major ampullate gland, is a composite proteinacious fiber with highly repetitive Ala-Gly-rich domain. The unique combination of both high tensile strength and high elasticity makes spider dragline silk superior to almost any other natural or synthetic fibers. Cloning of the genes reveals that the silk is composed of at least two major proteins. Each protein component contains multiple repeats of modular structures that alternate between Ala-rich domains and Gly-rich domains. Molecular engineering not only opens a door to the production of spidroins but also provides a valuable experimental system to test and further establish the relationship between modular structures and mechanical properties. Here, based on our own studies, we review the latest progress of the modular structure and genetic engineering and outline the future prospects.     

Investigation of the effects of MoO_3 buffer layer on charge carrier injection and extraction by capacitance–voltage measurement

The effects of MoO3thin buffer layer on charge carrier injection and extraction in inverted configuration ITO/ZnO/MEH-PPV(poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene))/MoO3(0,5 nm)/Ag hybrid solar cells are investigated by capacitance–voltage measurement under dark and light illumination conditions.The efficiency of charge carrier injection and extraction is enhanced by inserting 5 nm MoO3thin layer,resulting in better device performances.Charge carrier transport of the whole device is improved and the interface energy barrier is reduced by inserting 5 nm MoO3thin buffer layer.The device fill factor is increased from 54.1%to 57.5%after modifying 5 nm MoO3.Simulations and experimental results consistently show that in the forward voltage under dark,the device with the 5 nm MoO3thin layer modification generates larger value of capacitance than the device without MoO3layer.While under illumination,the device with the 5 nm MoO3layer generates smaller value of capacitance than the device without the 5 nm MoO3layer in the bias region of reverse and before the peak position of maximum capacitance(VCmax).The underlying mechanism of the MoO3anode buffer layer on device current density–voltage characteristics is discussed.     

Constituent phases of the passive film formed on 2205 stainless steel by dynamic electrochemical impedance spectroscopy

The passive film formed on 2205 duplex stainless steel (DSS) in 0.5 M NaHCO₃+0.5 M NaCl aqueous solution was characterized by electrochemical measurements, including potentiodynamic anodic polarization and dynamic electrochemical impedance spectroscopy (DEIS). The results demonstrate that there is a great difference between the passive film evolutions of ferrite and austenite. The impedance values of ferrite are higher than those of austenite. The impedance peaks of ferritic and austenitic phases correspond to the potential of 0.15 and 0.25 V in the low potential range and correspond to 0.8 and 0.75 V in the high potential range. The evolutions of the capacitance of both phases are reverse compared to the evolutions of impedance. The thickness variations obtained from capacitance agree well with those of impedance analysis. The results can be used to explain why pitting corrosion occurs more easily in austenite phase than in ferrite phase.     

An improvement to the data processing course of electrochemical impedance technique

For some electrochemical systems the traditional data processing methods can not be met, so it is necessary to develop a new method to deal with these problems. When processing the electrochemical AC impedance data of titanium alloy TAl2 in 3% NaCl solution (at free corrosion potential, room temperature) a new method is developed which can detach the information of the interface resistance demonstrably from the interface capacitance. The results show that the interface resistance and capacitance are all functions of frequency. And the AC impedance of the resistance and capacitance obey the following relations:C(f)=104.01982 f-0.9292,R(f)=104.80011 (f+0.008)-0.90897, which is completely different from the traditional conception that the interface resistance and capacitance are constants. And this phenomenon is ubiquitous in titanium alloys according to the study. So perhaps it is an innate characteristic of interface.     

δ13CSC values of the loess-paleosol sequence in Dali area, Shaanxi Province, China, and paleoenvironmental implications

The carbon isotopic ratios of carbonate in the two profiles of the Dali area were analyzed and some new understandings on the influencing factors of the δ^13Csc value of the Iocss-paleosol sequence and its paleoenvironmental implications were discussed preliminarily in this report. The δ^13Csc value of the Dali Ioess-paleasol sequence is synchronizing with the variance of magnetic susceptibility basically and the negative peaks of the δ^13Csc curves are corresponding to the different developmental periods of the paleosol. It is believed that the intervention of the CO2 produced by plants will cause the decrease of the δ^13Csc value, the amplitude of which may be relevant to the paleovegetation density and the ancient humidity. The relative biomass of C4 plants in the vegetation will affect the sublevel change of the δ^13Csc. Low δ^13Csc value by and large indicates the environmental conditions of the relatively abundant vegetation and humid climate. During the last 250000 years, the period with the sparsest vegetation and the most arid climate is the phase of the loess in L2 depositing and the period with the most abundant vegetation and the most humid climate is the last interglacial period. The δ^13Csc curves of Dali also show that the High Temperature and Large Precipitation Event of the Qinghai-Tibetan Plateau during 40-30 kaBP had affected the Central Shaanxi Plain with relatively humid climate, and had apparent influence on the local vegetation and humidity.     

The Application of Ultrasonic in the Refining of Waste Silk Material

The treatment effect of ultrasonic on waste silk material was studied in this paper. The results show that Ultrasonic can emulsify the pupal fat and accelerate the dissolving of sericin. For high pupal fat containing material, high temperature, high pH value and long time which may result in damage to silk fibre are not required and different levels of sericin can be kept according to requirement in ultrasonic refining. In addition, silk fibres are swollen and the breaking elongation of silk fibre is increased on prolonged ultrasonic treatment. But the breaking tenacity is damaged slightly.     

Analysis and Application on the Optimum Restrictive Parameters of Open Hydrostatic Slideway

Open hydrostatic slideway has many advantages, that is, high moving precision, low power in friction, non-crawling and long working life. Near constant clearances of hydrostatic slideway may be obtained in a wide load range by applying new type variable restrictors, new static characteristic formulas and optimum restrictive parameters. Hydrostatic slideway has two characters. One is that the scope of external load is very large. Generally, the largest load is 2 to 6 times the smallest, the other is that the algebraic equation is a horizontal S shape curve, showing that the relation between slideway clearance and external load is a three exponents formula. The curve of the numerical values of this kind of three exponents formula just is the working curve when the hydrostatic slideway is moving, if one section is selected as the slideway work curve randomly without any analysis, the slideway clearance will be changed acutely along with the variation of external load. Selecting the optimum restrictive parameters and the beeline through two inflexions of the curve or tangent of the curve as the range of workload can ensure the minimal change of sliding clearance. Simultaneously, the hydrostatic sliding way has high beeline moving precision.     

Corrosion behavior of ferritic stainless steel with 15wt% chromium for the automobile exhaust system

The effect of chloride ion concentration, pH value, and grain size on the pitting corrosion resistance of a new ferritic stainless steel with 15wt% Cr was investigated using the anodic polarization method. The semiconducting properties of passive films with different chloride ion concentrations were performed using capacitance measurement and Mott-Schottky analysis methods. The aging precipitation and intergranular corrosion behavior were evaluated at 400–900℃. It is found that the pitting potential decreases when the grain size increases. With the increase in chloride ion concentration, the doping density and the flat-bland potential increase but the thickness of the space charge layer decreases. The pitting corrosion resistance increases rapidly with the decrease in pH value. Precipitants is identified as Nb(C,N) and NbC, rather than Cr-carbide. The intergranular corrosion is attributed to the synergistic effects of Nb(C,N) and NbC precipitates and Cr segregation adjacent to the precipitates.     

Are topological relations dependent on the shape of spatial objects?

Topology is normally considered as independent of shape of spatial objects. This may not necessarily be true in describing relations between spatial objects in GIS. In this paper, we present proof that the topological relations between spatial objects are dependent on the shape of spatial objects. That is, that the topological relations of non-convex sets cannot be deformed to the topological relations of convex sets. The significant theoretical value of this paper is on its findings that topology of spatial objects is shape dependent. This indicates that when we want to describe topological relations between spatial objects in GIS, both topology and the shape of objects need to be considered. As a result, spatial data modeling, query and analysis based on the existing understanding of topology of spatial objects may need re-assessed.     

Zircon U/Pb dating and Hf-O isotopes of the Zhouan ultramafic intrusion in the northern margin of the Yangtze Block, SW China: Constraints on the nature of mantle source and timing of the supercontinent Rodinia breakup

The Zhouan ultramafic intrusion in the northern margin of the Yangtze Block is mainly composed of lherzolite.Zircon grains selected from lherzolite are irregular in shape with distinct oscillatory and sector zoning and have Th/U ratios ranging from 0.8 to 10.6,indicating a magmatic origin.The weighted average 206 Pb/238 U age is 637±4 Ma (2σ,n=15),which can be considered as the crystallization age of the Zhouan intrusion.Zircon grains have δ18O values ranging from 5.2‰ to 7.0‰,with an averaged value of 5.8±0.4‰ (1σ,n=33),similar to the mantle δ18O value of zircon.Their 176Hf/177Hf(t) ratios range from 0.282410 to 0.282594 with εHf(t) values ranging from 1.3 to 7.6,lower than the corresponding value of the depleted mantle (～15),indicating an enriched mantle source.The enriched mantle source may have generated from a metasomatized lithospheric mantle with subducted slab.A number of ～635 Ma mafic-ultramafic intrusions in the Suizao basin are associated with coeval bimodal volcanics of the Yaolinghe Formation,indicating a continental rift setting.The ～635 Ma magmatic event in this region may represent the product of the last breakup of the Rodinia supercontinent in the northern margin of the Yangtze Block at Neoproterozoic.     

Theoretical critical value curve and driving force formation of ecological migration in the arid land

The features of the fragile eco-environment of the arid land decide that its capacity of disturbance-resistance is lower. The natural desert oases in the arid land are in mosaic patches distributed in a wide Gobi desert. The population distribution is greatly dependent on water resources. The population is characterized with dispersed distribution, simple production and living style, and poverty and remoteness. The reason why the ecological migrations are carried out lies in the ecological problems. ＂Ecological degradation＂ is the main driving force of the ecological migration. Then, the strength of the driving force depends on the degree of ecological degradation. Hence, whether to carry out ecological migration depends on the extent of ecological degradation. Theoretically, the critical value curve for calculating ecological migration in the arid land is put forward through comprehensive research of relative problems of ecology, economics etc., combined with the ecological migration experience in the arid land, and based on the features of the arid environment. In this article, with this curve, the theoretical research and some practice of the ecological migration have been done from the perspective of natural behavior and governmental behavior of the driving force formation of ecological migration. It analyses the active driving force （factors） and negative forces （factors）, and points out the timing and steps of implementing the ecological migration in the arid land. The theoretical curve embodies certain originality and applicability, which provides a quantitative method for evaluating the degree of ecological degradation and the theoretical base for implementing ecological migration projects.     

Effect of feeding ratios on the structure and electrochemical performance of graphite oxide/polypyrrole nanocomposites

Graphite oxide (GO)/polypyrrole (PPy) nanocomposites (GPYs) were synthesized using in situ polymerization.The effect of the feeding ratios of pyrrole and GO on the structure and electrochemical performances of GPYs was investigated.The structure was characterized via Fourier-transform infrared spectroscopy,scanning electron microscopy,transmission electron microscopy and X-ray diffraction.The electrochemical performance was characterized via cyclic voltammetry,galvanostatic charge-discharge and electrochemical impedance spectroscopy.The results indicate that the more pyrrole is added to GO (with GO concentrations of 20% and 50%),the more agglomeration of both PPy and GO layers occurs.This is detrimental to the capacitance utilization of PPy.When the feeding ratio of GO:pyrrole is 80:20,PPys with nanofibrils are dispersed homogenously in/on the exfoliated layer of GO and the conductivity is enhanced.The capacitance utilization of PPy in a composite with a GO concentration of 80% (383 F/g) is higher than that of pure PPy (201 F/g),which indicates the presence of a synergistic effect between GO and PPy.     

Parameterization for fitting triangular mesh

In recent years, with the development of 3D data acquisition equipments, the study on reverse engineering has become more and more important. However, the existing methods for parameterization can hardly ensure that the parametric domain is rectangular, and the parametric curve grid is regular. In order to overcome these limitations, we present a novel method for parameterization of triangular meshes in this paper. The basic idea is twofold: first, because the isotherms in the steady temperature do not intersect with each other, and are distributed uniformly, no singularity (fold-over) exists in the parameterization; second, a 3D harmonic equation is solved by the finite element method to obtain the steady temperature field on a 2D triangular mesh surface with four boundaries. Therefore, our proposed method avoids the embarrassment that it is impossible to solve the 2D quasi-harmonic equation on the 2D triangular mesh without the parametric values at mesh vertices. Furthermore, the isotherms on the temperature field are taken as a set of iso-parametric curves on the triangular mesh surface. The other set of iso-parametric curves can be obtained by connecting the points with the same chord-length on the isotherms sequentially. The obtained parametric curve grid is regular, and distributed uniformly, and can map the triangular mesh surface to the unit square domain with boundaries of mesh surface to boundaries of parametric domain, which ensures that the triangular mesh surface or point cloud can be fitted with the NURBS surface.