基于空间形成视点的城市与农村关系的再考察

基于空间形成的视角,文章探讨了现代城市与农村之间的关系。文章认为,城市与农村之间的差异反映出它们自身所具有的属性,从而在等质空间中形成了不同性质的空间。在市场经济理论中,寻求与场所性结合的商品消费萌芽是理解与社会分工并列的地理差异的关键。与其说农村地域活力需引进域外企业,倒不如说以依靠地域内部主体性的供求为重点,以形成地域循环的产业结构为目标的"内生式发展"。资本主义的发展尽管导致了城市与农村的对立关系,但另一方面,在因资本主义的渗透呈现出的各种矛盾中,能够找到城市与农村相互补充的存在关系。作者依据经济全球化发展,认为城市与农村的进一步等质化或许能够孕育出新型的城乡关系。

浅谈阴谋犯与预备犯的关系

阴谋犯是指两人以上就实行特定的犯罪进行谋议、达成合意的犯罪形态。阴谋犯与预备犯在本质上都是着手前的未完成形态,就大陆法系国家而言,阴谋犯的阴谋行为与预备犯的预备行为是各自独立的准备行为。但它们的独立性仅体现在行为样态的区分上,而不在于本质上的差异,即它们统一于"准备行为"这一本质——两者自然属性相同,社会属性等价。立法区分阴谋犯与预备犯有直接和深层次原因。

Pharmacokinetics of nifedipine sustained-release tablets in healthy Chinese volunteers

Aim To establish a LC-MS method for determining the concentration of nifedipine in human plasma and to evaluate the pharmacokinetic characteristics of nifedipine sustained-release tablets. Methods A XB-C18 （5 μm, 4.6 mm ×150 mm） column and a mobile phase of methanol： 0.01 mol·L^-1ammonium acetate （60：40, V/V） were used to separate nifedipine, the detections was accuracy under atmosperic pressure electronic spray ionization （AP-ESI） mode and ion mass spectrum （m/z） of 314.9 [M＋H]^＋ for nifedipine, and 320.8 [M＋H]^＋ for lorazepam （Internal Standard, IS）. Results The linear range of nifedipine was 0.3 - 80 ng·mL^-1 （ r = 0.9997）, and the limit of quantitation （LOQ） was 0.3 ng·mL^-1. The nifedipine pharmacokinetic parameters after a single dose of 20 mg nifedipine sustained-release tablets test （T） or reference （R） were as the followings, t1/2 （6.73 ± 2.00） h and （7.04 ± 2.18） h, Tmax （4.28 ± 0.70） h and （4.48 ± 0.70） h, Cmax（39.66 ± 10.58） ng·mL^-1 and （40.19 ± 10.97） ng·mL^-1, AUC0-36 （391.63 ± 108.55） ng·mL^-1·h and （387.57 ± 121.51） ng·mL^-1·h, and AUC0-∞ （408.28 ± 121.16） ng·mL^-1·h and （406.15 ± 133.13） ng·mL^-1·h. The relative bioavailability of nifedipine sustained-release tablets （test） was （103.02 ± 13.93） %. Conclusion LC-MS method for the determination of concentrations of nifedipine in human plasma was sensitive and accurate, and could be used in nifedipine bioavailability and pharmacokinetic studies.

Free dendritic growth model incorporating interfacial nonisosolutal nature due to normal velocity variation

Considering both the effects of the interfacial normal velocity dependence of solute segregation and the local nonequilibrium solute diffusion,an extended free dendritic growth model was analyzed.Compared with the predictions from the dendritic model with isosolutal interface assumption,the transition from solutal dendrite to thermal dendrite moves to higher undercoolings,i.e.,the region of undercoolings with solute controlled growth is extended.At high undercoolings,the transition from the mainly thermal-controlled growth to the purely thermal-controlled growth is not sharp as predicted by the isosolute model,but occurs in a range of undercooling,due to both the effects of the interfacial normal velocity dependence of solute segregation and the local nonequilibrium solute diffusion.Model test indicates that the present model can give a satisfactory agreement with the available experimental data for the Ni-0.7% B（mole fraction） alloy.

Genetic predisposition to inflammation:a new risk factor of Alzheimer's disease

Inflammation has been shown to play an important role in the progression of Alzheimer＇s disease （AD）. Recent epidemical study indicates that the incidence of AD in some populations is substantially influenced by the gene polymorphisms of the inflammation mediators. Meanwhile, an ensured risk factor, the ApoE ε4 allele is also reported to directly promote inflammation. Accordingly, it appears that an individual genetic background has partly determined his predisposition for AD by the extent of the inflammation response to the chronic stimulus by β-amyloid peptide （Aβ） deposits and other antigen stressor in the elderly. Hence we present a hypothesis that the inflammation genotypes may contribute to AD susceptibility. This may provide a new orientation both for future identification of individuals at risk and for personalized medication.

The Reissner-Sagoci problem for transversely isotropic piezoelectric half-space

Based on the general solution of piezoelectric media and the extended Cerruti solution for tangential point forces acted on the surface of transversely isotropic piezoelectric half-space (Ding and Chen, 2001), the electro-elastic fields in a transversely isotropic piezoelectric half-space caused by a circular flat bonded punch under torsion loading, which is called Reissner-Sagoci problem, are evaluated by first evaluating the displacement functions within the contact region and then differentiating them. All the coupling electro-elastic fields are expressed by elementary functions and are convenient to be used. Numerical results are finally presented.

A symplectic eigensolution method in transversely isotropic piezoelectric cylindrical media

This paper reports establishment of a symplectic system and introduces a 3D sub-symplectic structure for transversely isotropic piezoelectric media. A complete space of eigensolutions is obtained directly. Thus all solutions of the problem are re- duced to finding eigenvalues and eigensolutions, which include zero-eigenvalue solutions and all their Jordan normal form of the corresponding Hamiltonian matrix and non-zero-eigenvalue solutions. The classical solutions are described by zero-eigen- solutions and non-zero-eigensolutions show localized solutions. Numerical results show some rules of non-zero-eigenvalue and their eigensolutions.

Analyses and Simulation of V-I Characteristics for Solar Cells Based on P-N Junction

Through theoretical analyses of the Shockley equation and the difference between a practical P-N junction and its ideal model, the mathematical models of P-N junction and solar cells had been obtained. With Matlab software, the V-I characteristics of diodes and solar cells were simulated, and a computer simulation model of the solar cells based on P-N junction was also established. Based on the simulation model, the influences of solar cell’s internal resistances on open-circuit voltage and short-circuit current under certain illumination were numerically analyzed and solved. The simulation results showed that the equivalent series resistance and shunt resistance could strongly affect the V-I characteristics of solar cell, but their influence styles were different.

Application of Hamiltonian system for two-dimensional transversely isotropic piezoelectric media

This paper presents a symplectic method for two-dimensional transversely isotropic piezoelectric media with the aid of Hamiltonian system. A symplectic system is established directly by introducing dual variables and a complete space of eigensolutions is obtained. The solutions of the problem can be expressed by eigensolutions. Some solutions, which are local and are neglected usually by Saint Venant principle, are shown. Curves of non-zero-eigenvalues and their eigensolutions are given by the numerical results.

Acacia mangium and Eucalyptus urophylla in Northern Vietnam： The Relationship between Silvicultural Activity and Quality of Stand

This paper sets out to determine the link between socio-economic attributes of smallholders, silvicultural activity and the stand quality of Acacia mangium and Eucalyptus urophylla plantations in two unrelated communes in Phu Tho province, Vietnam. The necessary data was collected by interviewing the smallholders and conducting inventory of the stands. The data was analyzed with descriptive statistics, Mann-Whitney tests and Spearman correlations. More silvicultural practices were conducted by A. mangium planters with larger areas. Most of the smallholders practiced the suggested silvicultural activities. Productivity was affected by pruning in medium quality sites. This research recommends that smallholders were supported with incentives for the plantation establishment, education for smallholders in silvicultural techniques, organization and development activities for the wider market.

Water-Soluble Rare Earth Elements in Some Soils of China

Water-soluble rare earth elements (WSREEs) of four typical soil profiles in China were determined by using a high-resolution inductively coupled plasma mass spectrometer. Results showed that the contents of WSREEs decreased from upper layer to lower layer of soils in the southern part of China with a high rainfall and low pH but increased for soils in the northern part of China with a low rainfall and relatively higher pH. Contents of WSREEs in soils were lower than 100 μg kg-1 in most casest and varied greatly with both different soils and different layers of the same profile. The highest content was 2816.3 μg kg-1 but the lowest was 17.6 μg kg-1 only. The content of individual rare earth iement (REE) in the soil solution also varied greatly with the highest one ranging from 8.4 to 1373 μg kg-1 for Ce and the lowest one from 0.05to 4.48 μg kg-1 for Lu. The sum of WSREEs in the first soil layers ranged from 121.5 to 345.6 μg kg-1.Great variations existed among ratios of REEs extracted with water to the total REEs of soils, ranging from 0.02×10-3 to 13.2×10-3. But as the upper layer was considered, the ratio showed only a small difference,ranging from 0.79×10-3 to 1.69×10-3.

Quality Stability of Multi-Station Assembly Process Based on Variation Stream

To analyze the physical structure of assembly process and assure product quality, the quality stability of multi-station assembly process was investigated. First, the assembly process was modeled as a one-dimensional discrete variant system by state space equation based on variation stream. Then, the criterion to judge whether the process is stable or not and the index, stability degree, to show the level of stability were proposed by analyzing the bounded-input bounded-output (BIBO) stability of system. Finally, a simulated example of a sheet metal assembly process with three stations, was provided to verify the effectiveness of the proposed method.

Social rank and cortisol among female rhesus macaques (Macaca mulatta)

In animal societies, some stressful events can lead to higher levels of physiological stress. Such stressors, like social rank, also predict an increased vulnerability to an array of diseases. However, the physiological relationship between social rank and stress varies between different species, as well as within groups of a single species. For example, dominant individuals are more socially stressed at times, while at other times it is the subordinate ones who experience this stress. Together, these variations make it difficult to assess disease vulnerability as connected to social interactions. In order to learn more about how physiological rank relationships vary between groups of a single species, cortisol measurements from hair samples were used to evaluate the effects of dominance rank on long-term stress levels in despotic and less stringent female rhesus macaque hierarchal groups. In despotic groups, cortisol levels were found not to be correlated with social rank, but a negative correlation was found between social rank and cortisol levels in less stringent hierarchies. Low ranking monkeys in less stringent groups secreted elevated levels of cortisol compared to higher ranking animals. These data suggest that variations in the strictness of the dominance hierarchy are determining factors in rank related stress physiology. The further consideration of nonhuman primate social system diversity and the linear degree of their hierarchies may allow for the development of valid rank-related stress models that will help increase our understanding and guide the development of new therapeutics for diseases related to human socioeconomic status.

Effect of Particle＇s Size on the Structural and Dynamical Properties in 2D Dusty Plasma

In a two-dimensional （219） dusty plasma system, the size of particles is considered under two different interparticle potentials （Yukawa potential and Dressed potential）. The structural and dynamical characters are investigated by molecular dynamics simulation respectively. The results show that the 2D systems via Yukawa and Dressed potentials have a different critical coupling constant F corresponding to the systems beginning to coagulate and exhibit different crystal configurations. Also we find that the size of particles has little influence on the 2D system＇s structure characters.

Fracture prediction in non-isothermal viscous pressure bulging of aluminum alloy sheet using ductile fracture criterion

The failure of AA3003 aluminum alloy sheet metal was predicted for non-isothermal viscous pressure bulging (VPB). Utilizing the coupled thermo-mechanical finite element method combined with ductile fracture criterion, the calculations were carried out for non-isotherm VPB at various temperatures and the influences of the initial temperature of viscous medium on failure mode of bulge specimens were investigated. The results show that the failure modes are different for the non-isothermal VPB with different initial temperatures of viscous medium. For the non-isothermal VPB of AA3003 aluminum alloy sheet with initial temperature of 250 ℃, when the initial temperature of viscous medium ranges from 150 to 180 ℃, the formability of sheet metal can be improved to a full extent. The validity of the predictions is examined by comparing with experimental results.

Functionality of Protein Isolates from Argentine Anchovy （Engraulis anchoita） Residue Obtained Using pH Shift Processing

The aim of this study was to obtain a protein isolate from Argentine anchovy （Engraulis anchoita） residue produced using the pH shifting process, with acid and alkaline solubilization and isoelectric precipitation of the protein, and evaluate their functional properties. The lowest solubility was obtained at pH 5 where 8.32% and 2.96% were found for acid and alkali respectively. The highest solubility was obtained at extreme pH. The maximum water holding capacity was presented by the alkaline protein isolate at pH 11 （9.63 g H20/g protein）. The oil holding capacity was 4.20 mL/g protein, 7.26 mL/g of protein for the acid and alkaline protein isolates, respectively. The strain showed higher oil holding capacity in alkaline pH, lower solubility in pH near the protein isoelectric point and a lower capacity to retain water in extreme pH when compared with the acid isolate.

Exploration and Practice of Improving Higher Mathematics Teaching Quality of Teaching at Different Levels

Teaching content of Higher Mathematics is systematic and rigor with a high degree of abstraction. Because different students are on the different basis and different disciplines have various requirements, mathematics is generally difficult for students. In order to improve the quality of teaching mathematics, we should make use of individualized teaching and teaching by different levels in order to achieve the best teaching results.

Analysis of 13Cr bloom solidification structure using CA-FE model

Solidification structure is critical in the control of the mechanical properties and quality during the continuous casting process. The thermo-physical properties of 13 Cr steel added some rare metals, such as Mo, V, Nb, are measured to better understand the solidification structure of 13 Cr bloom. A computational model using CA-FE(cellular automation-finite element) method coupled with heat transfer model is developed to describe the solidification structure in continuous casting process. It is found that the calculated solidification structure is in good agreement with the observed data. The influence of casting speed and superheat on the solidification structure of the bloom is studied in detail. In order to obtain more equiaxed crystal ratio and low degree of the segregation in the bloom, the optimized casting speed 0.6 m/min and superheat less than 25 °C are determined for the caster. Using the optimized manufacturing parameters, these samples are 60% with the equiaxed zone ratio of 8%–10% and below the degree of segregation 1.05.

Research on Permeability of Multiphase Medium of Middle to High-Rank Coals

The permeability of coal of middle to high ranks were tested using He,CH 4 and H 2O in single phase medium and using CH 4 and H 2O in double phase medium. The relation between adsorption and permeability of those media was discussed, and the seepage flow characteristics of methane-water medium in coals were analyzed. The result shows that the coalbed methane resource of high-rank coal reservoirs in China is still recoverable.

Comparative analysis on homogeneity of Pb and Cd in epoxy molding compounds

Reference materials for quantitative determination of regulated heavy metals, such as Pb and Cd in electronic components, were designed and investigated in terms of stability and homogeneity. Reference materials with two concentration levels of heavy metals were prepared by spiking Pb and Cd compounds to epoxy molding compounds made by mixing silica powders and epoxy resin. The concentration changes of the reference materials during stability test for 1 a were not observed. In the homogeneity assessment, the as-prepared reference materials were studied by using three different analytical tools, inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray fluoroescence spectrometry (XRF) and laser ablation ICP mass. The results show different homogeneities by the characteristics of analytical tools and the materials.