人才引领助推乡村振兴发展路径探究——基于吉登斯结构化理论的案例分析

近年来,人才引领对推进乡村振兴发展作用和价值愈发凸显,但同时面临农民主体缺位、外部人才力量无法与基层有效对接等现实困境。对于乡村人才的研究多聚焦在单类型人才培育研究视角,缺少对人才引领内源、外源动力的整体性分析以及人才引领的剖面实践展示。文章借助吉登斯结构化理论分析框架,对农民主体内部人才引领和多元主体协同外部人才引领进行结构化分析,并结合M县的案例探索提出人才引领乡村振兴的发展路径。

Non-isothermal oxidation and ignition prediction of Ti-Cr alloys

The non-isothermal oxidation behavior and oxide scale microstructure of Ti-Cr alloy （0≤w（Cr）≤25%） were studied from room temperature to 1723 K by thermogravimetric analysis （TGA）, X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The influencing mechanism of chromium on the oxidation resistance of Ti-Cr alloys was discussed. The results show that the oxidation resistance of the alloys decreases with Cr below a critical chromium content wC and increases above wC; above 1000 K, the oxidation kinetics obeys parabolic rule and titanium dominates the oxidation process; after oxidation, the oxygen-diffusing layer is present in the alloy matrix, the oxide scale is mainly composed of rutile whose internal layer is rich in chromium, and chromium oxides separated out from TiO2 near the alloy-oxide interface improve the oxidation resistance. Ignition of metals and alloys is a fast non-isothermal oxidation process and the oxidation mechanism of Ti-Cr alloys during ignition is predicted.

The Formation of Colored Film on Stainless Steel and the Study for Surface Structure

This paper discusses the coloration process on the stainless steel and the properties of the film. The compositions, morphology and structure of colored films on stainless steel are studied by using SEM,AES,AFM,STM. The diffusion controlled mechanisms of films and calculation formula of surface electropotential difference are discussed.

OPTIMUM CUTTING ANALYSIS METHOD OF MEMBRANE STRUCTURE

By the optimum theory, a new cutting analytical method of the membrane structure is developed. The B-spline curve is applied to make smooth the boundary of the membrane strip. By this method, the cutting accuracy is improved. Finally, a cutting analysis example of a tension membrane structure is given.

Molecular reconstruction model based on structure oriented lumping and group contribution methods

Molecular management is a promising technology to face challenges in the refining industry, such as more stringent requirements for product oil and heavier crude oil, and to maximize the value of every molecule in petroleum fractions. To achieve molecular management in refining processes, a novel model that is based on structure oriented lumping(SOL) and group contribution(GC) methods was proposed in this study. SOL method was applied to describe a petroleum fraction with structural increments, and GC method aimed to estimate molecular properties. The latter was achieved by associating rules between SOL structural increments and GC structures. A three-step reconstruction algorithm was developed to build a representative set of molecules from partial analytical data. First, structural distribution parameters were optimized with several properties. Then, a molecular library was created by using the optimized parameters. In the final step, maximum information entropy(MIE) method was applied to obtain a molecular fraction. Two industrial samples were used to validate the method, and the simulation results of the feedstock properties agreed well with the experimental data.

Research on the Agriculture Production Structure in Shandong Province Based on the Grey Relational Dynamic Analysis

In accordance with grey relational dynamic analysis, overall structure and inner structure of agriculture were analyzed and the grey relational sequence inte- grals were concluded of Shandong agriculture during 2003-2014. Besides, the re- search analyzed the contributions by specific agricultural sectors and Shandong a- gricultural structure from natural endowments, policy, and agricultural modernization. Finally, the development countermeasures and suggestions were proposed.

Structural Variation Analysis of Mutated Nannochloropsis oceanica Caused by Zeocin Through Genome Re-Sequencing

Zeocin can cause double strand breaks of DNA and thus may be employed as a mutagen. In this study, two strains of Nannochloropsis oceanica, the wild and the Zeocin-tolerant strains, were re-sequenced to verify such function of Zeocin, The results showed that Zeocin can mutate the N. oceanica genome and cause the structural variation. Zeocin either swept away or selected the alleles of genes functioning in ubiquitin-mediated proteolysis, alpha-linolenic acid metabolism, ascorbate and aldarate metabolism, ribosome biogenesis, and circadian rhythm, indicating that N. oceanica may have adjusted its metabolic performances for protein, carbohydrate, and lipid, and changed its ribosome biosynthesis and living rhythm to survive in Zeocin containing medium. In addition, Zeocin caused mutation may have influenced the expression of a set of tanscription factors. It was concluded that Zeocin effectively caused the structural variation of the genome of N. oceanica, and forced the microalgae to select out the alleles of a set of genes around these variations in order to adapt to Zeocin containing medium. Further studies on the genetic basis of the phenotypic adaptation of this haploid and asexual microalga and the application of Zeocin to its genetic improvement are very important.

Comparison of Sensory Characteristics of Green Tea Produced in Thai Nguyen and Phu Tho Province, Vietnam

Green tea is a popular product with a high consumption in Vietnam. Moreover, green tea produced in Tan Cuong commune, Thai Nguyen province, has long been recognized for its superior quality to those coming from other regions of the country. This study aims at comparing the tea from Thai Nguyen and Phu Tho and finding out if the difference can be identified through sensory analysis. Two products picked from Tan Cuong, Thai Nguyen province, and two others from Phu Ho district, Phu Tho province were evaluated by a trained panel of 12 judges （11 women and 1 man）. The sensory evaluation of the dry tea （11 descriptors） was carried out separately from the brewed tea （21 descriptors） and brewed leaf （five descriptors） using an unstructured intensity scale （10 cm）. Statistic analyses have shown differences between regions in all three groups of attributes： dry leaf, liquor and brewed leaf.

A New Cyclic Bisdesmoside from Tubers of Bolbostemma paniculatum

The structure of tubeimoside V (1), a new cyclic bisdesmoside, isolated from tubers of Bolbostemma paniculatum (Tu Bei Mu), was established by means of 2D NMR spectral and chemical methods. Compound 1 has inter-saccharide chain bridging by a dicrotalic acid to form a unique macrocyclic structure.

Analytic Study on a Plane Stress Tensile Crack in a Power-Law Hardening Material

Aim To construct an analytic solution for the asymptotic field near a tensile cracktip of power-law hardening material under Plane stress condition. Methods Constructing funtion method was used. Results The exact asymptotic field was found. Conclusion The exact analytic solution for the problem is available.

Vibration Suppression Analysis for Supporter with Constrained Layer Damping

By analyzing the correlation between modal calculations and modal experiments of a typical supporter, an effective finite element analysis( FEA)model of the actual aerospace supporter is created. According to the analysis of constrained viscoelastic damping, the strategies of PVC have been worked out, and the correlation between modal calculations and modal experiments of the supporter has also been computed, and then, an experiment has been designed based on the calculation results. The results of experiments verify that the PVC strategy can effectively suppress vibration.

Theoretical Study of the AIEt3-Promoted Tandem Reductive Rearrangement of Epoxides

The AIEt3-promoted tandem reductive rearrangement reactions of epoxides was studied at B3LYP/6- 31C（d,p） level. For the model compound α-hydroxy epoxides, two possible reaction pathways Ⅰ and Ⅱ were calculated. The main difference is the order of ethylene release and six- to five-member ring rearrangement. The ring contraction rearrangement in pathway Ⅰ is the first step and this step is the rate controlling step with a free energy barrier of 116.62 kJ/mol. For pathway Ⅱ, the ethylene release occurs first, and is followed by a six-member ring opening reaction which is the rate controlling step, and the barrier is 251.38 kJ/mol. The reason for such high barrier is that the ethylene release results in the following reaction being more difficult. The results show that pathway Ⅰ （C-C rearrangement and then ethylene release） is more favorable, which is consistent with experimental results.

Translocation of Polymer Chains Through a Channel with Complex Geometries

The elastic behavior of a single chain transporting through complex channel which can be seen as the combination of three different channels （left channel, middle channel, and right channel, respectively） is investigated using the new pruned-enriched Rosenbluth method with importance sampling. The elastic force during the translocation process is calculated. At the entrance into the middle channel, there is the first plateau in the curve of the elastic force f （f〉0） versus x, here x represents the position of the first monomer along the x-axis direction. When the first monomer moves to a certain position, a second plateau is observed with the elastic force f〈0, which represents spontaneous translocation. The free energy difference between the subchain in the right channel and the subchain in the left channel may drive the transloeation. The influence of chain length and width of the left and right channels on the translocation process are also investigated. From the simulation results, more detailed explanations for the reason why the component translocation time is not the same for different channels can be presented.

Ab initio Study on Structures and Isomerization of Magnesium Fluorosilylenoid H2SiFMgF

The structures and isomerization of magnesium fluorosilylenoid H2SiFMgF were investigated by ab initio molecular orbital theory. Four equilibrium structures and three isomeric transition states were located and fully optimized at the B3LYP/6-31G（d,p） and G3MP2B3 levels, respectively. Based on the B3LYP/6- 31G（d,p） optimized geometries, harmonic frequencies of various structures were obtained and 29Si chemical shifts were calculated. The solvent effects were investigated by means of the polarizable continuum model using THF as a solvent at B3LYP/6-31G（d,p） level. Isomerization paths for isomers were confirmed by intrinsic reaction coordinate calculations. The calculated results show that tetrahedral structure has the lowest energy and is the most stable; tetrahedral, three-membered ring, and p-complex structures are suggested to be the experimentally detectable ones; and a-complex structure has the highest energy and will not exist.

Analysis on Genomic Structure Changes and Diversity of Introgression Lines in Dongxiang Wild Rice(Oryza rufipogon Griff.)

[Objective] The aim of the study was to make research on genomic struc- ture variation and variety analysis of Dongxiang wild rice. [Method] Introgression groups of BC1F6 were based on donor of Oryza rufipogon Griff. and receptor of O. sativa sp. indica Kate. Strains of 239 in the group were analyzed on Polymor- phism with the help of 25 couples of SSR primers distributed in 12 pairs of chromo- somes. [Result] Gene fragments of O. rufipogon Griff. were found penetrated in the 25 microsatellite sites and most of the groups kept the parents of Xieqinzao B or DNA sequence of O. rufipogon Griff. The average rate of recurrent homozygous bands was 78.13% in the ILs, but the highest was 94.98% （amplified by primer RM131） and the lowest was 60.25% （RM171）. The average rate of donor homozy- gous bands was 13.37%, but the highest was 32.64% （RM171） and the lowest was 2.93% （RM1095）. There were numerous heterozygous sites in the population and the average heterozygosis rate was 5.62%, while the highest was 10.04%（RM401）. Moreover, we found some parental fragments were lost and some novel fragments were not detected in either parent in BC1F6 population. The average rate of lost bands was 2.88%, while the highest was 13.39% （RM311） and the lowest was 0 （RM401）. The average rate of new bands was 1%. The average of Nei＇s gene di- versity （He） and Shannon＇s Information index （I） were 0.276 and 0.457 respectively in high generation of introgression lines. [Conclusion] The study demonstrated that distant hybridization led to extensive genetic and epigenetic variations in high gener- ation of introgression lines, which expanded the base of genetic variation and laid an important foundation for rice improvement and germplasm innovation.

Mechanism Design and Motion Analysis of Heavy⁃Load Transfer Robot with Parallel Four⁃Bar Mechanism

Heavy-load transfer robots are widely used in automobile production and machinery manufacturing to improve production efficiency.In order to meet the needs of large billet transfer,a 4-DOF transfer robot is designed in this paper,which consists of parallel four-bar mechanisms.The Jacobian matrix referring to the mapping matrix from the joint velocity to the operating space velocity of the transfer robot can be solved by the differential-vector method.The mean value of the Jacobian matrix condition number in the workspace is used as the global performance index of the robot velocity and the optimization goal.The constraint condition is established based on the actual working condition.Then the linkage length optimization is carried out to decrease the length of the linkage and to increase the global performance index of velocity.The total length of robot rods is reduced by 6.12%.The global performance index of velocity is improved by 45.15%.Taking the optimized rod length as the mechanism parameter,the distribution of the motion space of the transfer robot is obtained.Finally,the results show that the proposed method for establishing the Jacobian matrix of the lower-mobility robot and for the optimization of the rods based on the velocity global performance index is accurate and effective.The workspace distribution of the robot meets the design requirements.

Characteristics of reactivity and structures of palm kernel shell (PKS) biochar during CO_2/H_2O mixture gasification

Palm kernel shell(PKS)biochars with different levels of carbon conversion were initially prepared using a tube furnace,after which the reactivity of each sample was assessed with a thermogravimetric analyzer under a CO_2 atmosphere.The pore structure and carbon ordering of each biochar also examined,employing a surface area analyzer and a Raman spectroscopy.Thermogravimetric results showed that the gasification index R_sof the PKS biochar decreased from 0.0305 min^(-1) at carbon conversion(x)=20% to 0.0278 min^(-1)at x=40%.The expansion of micropores was the dominant process during the pore structure evolution,ad mesopores with sizes ranging from 6 to 20,48 to 50 nm were primarily generated during gasification under a CO_2/H_2O mixture.The proportion of amorphous carbon in the PKS biochar decreased significantly as x increased,suggesting that the proportion of ordered carbon was increased during the CO_2/H_2O mixed gasification.A significantly reduced total reaction time was observed when employing a CO_2/intermittent H_2O process along with an 83.46% reduction in the steam feed,compared with the amount required using a CO_2/H_2O atmosphere.

Formation of [3]Pseudorotaxanes from β-cyclodextrin and a Series of Dicarboxylic Acids with Their Corresponding α,ω-alkanedicarboxylate Anions

Inclusion complexes between β-cyclodextrin （β-CD） and a series of dicarboxylic acids （DAn, n=11-15） were prepared by co-grinding and co-precipitation methods and the [3]pseudorotaxane structure of them was elucidated by FTIR, DTA and XRD characterizations. Inclusion complexes of β-CD and α,ω-alkanedicarboxylate anions （DAn^2-） were acquired by neutralizing β-CD/DAn different inclusion complexes with sodium hydroxide and the structure was also proved to be a pseudorotaxane structure by ^1H-NMR spectra and NOESY spectrum. Both the inclusion complexes of β-CD/DAn and β-CD/DAn^2- adopt the [3]pseudorotaxane structure with β-CD arranged in dimers threaded onto one aliphatic chain and the binding mode of 1：1 inclusion complex was excluded based on the consideration of chain conformations.

Nuclear power plant life extension:How aging affects performance of containments & other structures

This paper focuses on how aging can affect performance of safety-related structures in nuclear power plant (NPP). Knowledge and assessment of impacts of aging on structures are essential to plant life extension analysis,especially performance to severe loadings such as loss-of-coolant-accidents or major seismic events. Plant life extension issues are of keen interest in countries (like the United States) which have a large,aging fleet of NPPs. This paper addresses the overlap and relationship of structure aging to severe loading performance,with particular emphasis on containment structures.

Low Temperature One-Step Synthesis of Barium Titanate:Thermodynamic Modeling and Experimental Synthesis

A thermodynamic model has been developed to determine the reaction conditions favoring low temperature direct synthesis of barium titanate (BaTiO3). The method utilizes standard-state thermodynamic data for solid and aqueous species and a 0ebye-Huckel coefficients model to represent solution nonideality. The method has been used to generate phase stability diagrams that indicate the ranges of pH and reagent concentrations, for which various species predominate in the system at a given temperature. Also, yield diagrams have been constructed that indicate the concentration, pH and temperature conditions for which different yields of crystalline BaTiO3 can be obtained. The stability and yield diagrams have been used to predict the optimum synthesis conditions (e.g., reagent concentrations, pH and temperature). Subsequently, these predictions have been experimentally verified. As a result, phase-pure perovskite BaTiO3 has been obtained at temperature ranging from 55 to 85℃ using BaCl2, TiCl4 as a source for Ba and Ti, and NaOH as a precipitator.