从“正体”咏史到“变体”咏史——兼论咏史诗产生原因

狭义咏史是指作者直接歌咏历史题材,以寄寓思想感情,表达议论见解的一种诗歌类别。虽然咏史诗与用典和咏怀有某些相似之处,但是它又具备和后两者不同的特点,我们应该加以区别。咏史诗的产生和我国重史的民族传统及文人尚古心理有关,同时又受乐府民歌创作实践的影响。从“正体”咏史到“变体”咏史的转变,我们可以看到咏史诗从重客观铺陈到尚主观抒情的曲折发展历程。

论“学报体”及其改良

"学报体"指发表在我国社科学术期刊上的文章所体现出的某些共性,既涉及题材内容,又涉及风格气象。我国社科期刊自创立至今,事实上存在着作为"正体"的和作为"伪体"的两种"学报体"文章,前者应得到护持,后者应受到贬斥。"正体"文章之长的主要体现是:分学科门类表述高深问题研究新得;举充分依据细密论证大小论点;以人文关怀给力社会发展;有较多行文规范服务内容表达。"伪体"文章之弊主要表现为:形式完备而内容贫瘠;"八股化"程度严重;缺少淑世情怀。当今"学报体"文章的改良,应先从三个方面做起:变文章评价由"重量轻质"为"重质轻量";变文章体式由"一体独大"为"众体并茂";变文章语言由"重质轻文"为"质文双重"。

基于改进IDI指标体系的G20成员国信息通信技术发展水平研究

在国际电信联盟曾使用的信息通信技术(ICT)发展指数(IDI)基础上,提出改进的信息通信技术发展指数。通过分析2007—2020年二十国集团(G20)的19个成员国的IDI指数和ICT相关指标揭示了G20成员国在信息通信技术发展方面的特点和差异性。分析发现G20成员国信息通信技术发展水平均有较大幅度的提升,国家之间的信息通信技术发展差距逐渐缩小,但增长速度和发展水平仍存在较大差异;G20成员国中韩国、日本、法国、德国和英国的信息通信技术发展水平最高,美国、加拿大、澳大利亚、沙特阿拉伯和俄罗斯的信息通信技术发展居于G20成员国的中上水平,意大利、阿根廷、中国、巴西、土耳其的发展居于中下水平,墨西哥、南非、印度尼西亚和印度的信息通信技术发展水平较低。

简论近体诗格律的正与变

近体诗格律的“正体”是根据部分有代表性的作品概括出来的。唐代杰出诗人既创作了符合正体的辉煌篇章 ,也往往为了更好地表现特定情景或避免圆熟而突破正体 ,追求新变。清人针对这种不合“正体”的“变”提出了“拗救”说 ,的确有贡献 ;但远不足以解释所有变态。何况对于“正体”来说 ,“拗”而不“救”是“变” ,“拗”而能“救”也是“变”。新时期以来近体诗创作十分活跃 ,却过分拘守格律 ,知正而不知变。本文的撰写意在提供借鉴 ,或有助于创作质量的提高。

Optimization and Testing for PCR System of Rice by Orthogonal Design

[Objective] This study was to screen the economic or stable PCR system of rice and detect the generality of the selected system in different molecular markers based on PCR.[Method] With DNA extracted from rice leaves by CTAB method as the template,PCR system was optimized by L16(45)orthogonal design.[Result] Clear bands were amplified from 16 different combinations,but the amplification effects and yields had difference.The most economic and applicable system was as follows:20 ng DNA template,150 μmol/L dNT...

Important Works About Rules in Rules-Based Optical Proximity Correction

Considering the efficiency and veracity of rules based optical proximity correction (OPC),the importance of rules in rules based OPC is pointed out.And how to select,to construct and to apply more concise and practical rules base is disscussed.Based on those ideas,four primary rules are suggested.Some data resulted in rules base are shown in table.The patterns on wafer are clearly improved by applying these rules to correct mask.OPCL,the automatic construction of the rules base is an important part of the whole rules based OPC system.

A Kernel-Based Convolution Method to Calculate Sparse Aerial Image Intensity for Lithography Simulation

Optical proximity correction (OPC) systems require an accurate and fast way to predict how patterns will be transferred to the wafer.Based on Gabor's 'reduction to principal waves',a partially coherent imaging system can be represented as a superposition of coherent imaging systems,so an accurate and fast sparse aerial image intensity calculation algorithm for lithography simulation is presented based on convolution kernels,which also include simulating the lateral diffusion and some mask processing effects via Gaussian filter.The simplicity of this model leads to substantial computational and analytical benefits.Efficiency of this method is also shown through simulation results.

The Monotonicity Problems for Generalized Inverses of Matrices in H (n, ≥)

On the basis of the paoers[3—7],this paper study the monotonicity problems for the positive semidefinite generalized inverses of the positive semidefinite self-conjugate matrices of quaternions in the Lowner partial order,give the explicit formulations of the monotonicity solution sets A{1;≥,T_1;≤B^(1)}and B{1;≥,T_2≥A^(1)}for the(1)-inverse,and two results of the monotonicity charac teriaztion for the(1,2)-inverse.

A Model of a Single Electron Transistor of Metallic Tunneling Junctions and Its Validation

Based on the orthodox theory,a model of a single electron transistor （SET） of metallic tunneling junctions is built using the master equation method. Several parameters of the device, such as capacitance, resistance and temperature,are input into the model and thus the I-V curves are attained. These curves are consistent with those from other experiments; therefore, the model is verified. However, there still exists a difference between simulated results and experimental results,mainly comes from the stationary case of the master equation. In other words, precision of simulated results would be increased if the transient case of the master equation is considered. Moreover, the current increases exponentially at higher drain voltages, which is due to the fact that the barrier suppression is caused by the image charge potential.

Plastid Inheritance in Sweet Potato as Revealed by DNA Restriction Fingerprinting

The inheritance of chloroplast DNA (cpDNA) in sweet potato (Ipomoea batatas Lain.) was analyzed using DNA restriction fingerprinting. The cpDNA fingerprints of hybrids from reciprocal crosses between Xushu18 and AB78-1 were found to be identical to those of their female parents, which reveals that cpDNA of sweet potato is maternally inherited in this intervarietal crossing. This maternal cpDNA transmission pattern does not accord with the putative one based on former cytological studies. The plastid inheritance in Convolvulaceae has been briefly reviewed in this study, and the utility of DNA restriction fingerprinting analysis in the study of plastid inheritance is also discussed.

NUMERICAL SIMULATION OF SUPERSONIC AXISYMMETRIC FLOW OVER MISSILE AFTERBODY WITH JET EXHAUST USING POSITIVE SCHEMES

Supersonic axisymmetric jet flow over a missile afterbody containing exhaust jet is simulated using the second order accurate positive schemes method developed for solving the axisymmetric Euler equations based on the 2-D conservation laws.Comparisons between the numerical results and the experimental measurements show excellent agreements.The computed results are in good agreement with the numerical solutions obtained by using third order accurate RKDG finite element method.The results show larger gradient at discontinuous points compared with those obtained by second order accurate TVD schemes.It indicates that the presented method is efficient and reliable for solving the axisymmetric jet with external freestream flows,and shows that the method captures shocks well without numerical noise.

Inverse Halogen Bonds Interactions Involving Br Atom in the Electronic Deficiency Systems of CH3＋… Br-Y （Y--H, CCH, CN, NC）

Inverse halogen bonds interactions involving Br in the electronic deficiency systems of CH3＋...Br-Y （Y=H, CCH, CN, NC） have been investigated by B3LYP/6- 311＋＋G（d, p） and MP2/6-311＋＋G（d, p） methods. The calculated interaction energies with basis set super-position error correction of the four IXBs complexes are 218.87, 219.48, 159.18, and 143.05kJ/mol （MP2/6-311＋＋G（d, p））, respectively. The relative stabilities of the four complexes increased in the order： CH3＋ … BrCN〈CH3＋…- BrNC〈CH3＋… BrH≈CH3＋ …BrCCH. Natural bond orbital theory analysis and the chemical shifts calculation of the related atoms revealed that the charges flow from Br-Y to CH3e. Here, the Br of Br-Y acts as both a halogen bond donor and an electron donor. Therefore, compared with conventional halogen bonds, the IXBs complexes formed between Br-Y and CH3＋. Atoms-in-molecules theory has been used to investigate the topological properties of the critical points of the four IXBs structures which have more covalent content.

Optimization of PCR Reaction System for Random Single-strand DNA Pool in SELEX Technology

[Objective] This study aimed to optimize the PCR amplification conditions for random ssDNA pool in SELEX technology. [Method] L16（45） orthogonal experimental design was adopted for optimization of five important factors affecting PCR reaction system for random single-stranded DNA pool including Mg2＋ concentration, dNTP concentration, amount of Taq DNA polymerase, primer concentration and amount of random single-stranded DNA pool at four levels. Meanwhile, the annealing temperature and number of PCR reaction cycles were optimized to establish the optimal reaction system and PCR procedure. [Result] The optimal combination of PCR reaction system for random ssDNA pool was obtained, with a total system volume of 20 μl containing 2.0 μl of 10 × Buffer, 0.5 ng of random ssDNA pool, 2.5 mmol/L Mg2＋, 0.25 mmol/L dNTP Mixture, 0.6 μmol/L upstream and downstream primers and 1.5 U of Taq DNA polymerase; the optimal annealing temperature was 68 ℃ and the optimal number of cycles was 12. Under the above conditions, clear and stable bands with high specificity for random ssDNA pool were amplified. [Conclusion] This study laid the foundation for selection of parameters with higher specificity in SELEX technology.

Optimization of RAPD-PCR Reaction System for Glycyrrhiza uralensis Based on Orthogonal Design

[Objective] The aim was to obtain the optimum RAPD-PCR reaction system for Glycyrrhiza uralensis.[Method] Orthogonal design was adopted to screen the suitable concentration of four major factors（dNTPs,primers,Taq polymerase and DNA template） in PCR reaction system.[Result] The optimal reaction system obtained by orthogonal design was 25 μl in total volume,containing 2.5 μl of 10×PCR buffer solution（include MgCl2）,2.5 μl of 10 mmol/L dNTPs,2 μl（100 ng） of DNA template,2 μl of 10 μmol/L primers,0.4 μl（5 U） of Taq polymerase;the optimum annealing temperature was 34 ℃.[Conclusion] Orthogonal design was an effective method for the optimization of RAPD-PCR reaction system for G.uralensis.

RESEARCH ON MATRIX CRACK EVOLUTION OF CROSS-PLY CERAMIC MATRIX COMPOSITE

The matrix crack evolution of cross-ply ceramic matrix composites under uniaxial tensile loading is investigated using the energy balance method.Under tensile loading,the cross-ply ceramic matrix composites have five damage modes.The cracking mode 3 contains transverse cracking,matrix cracking and fiber/matrix interface debonding.The cracking mode 5 only contains matrix cracking and fiber/matrix interface debonding.The cracking stress of modes 3 and 5 appearing between existing transverse cracks is determined.And the multiple matrix crack evolution of mode 3 is determined.The effects of ply thickness,fiber volume fraction,interface shear stress and interface debonding energy on the cracking stress and matrix crack evolution are analyzed.Results indicate that the cracking mode 3 is more likely to appear between transverse cracks for the SiC/CAS material.

Research on Protoplast Preparation and Regeneration Conditions of Tremella aurantialba

[Objective] This study aimed to explore the protoplast preparation and re- generation conditions of Tremella aurantialba. [Method] Optimal combination of five factors affecting the protoplast preparation and regeneration of Tremella aurantialba was selected by using orthogonal experiment, including enzyme system, culture age, enzymolysis temperature, enzymolysis duration and osmotic stabilizer. [Result] The results showed that there were three release modes of Tremella aurantialba proto- plasts： release from top in the early period of enzymolysis, release from the side and release in situ. The optimal protoplast preparation condition was selecting mycelium cultured in liquid medium for 3 d, for enzymolysis in mixed enzyme solu- tion containing 1% of cellulase ＋1% of snailase ＋1% of lywallzyme at 36 ℃; for 4 h, with 0.6 mol/L sucrose as osmotic stabilizer, and the obtained preparation rate had reached 1.76 ×10^7 protoplasts/ml. The optimal regeneration condition was using mycelium cultured in liquid medium for 5 d, for enzymolysis in enzyme solution con- taining 1.5% of lywallzyme at 33 ℃ for 3 h, with 0.6 mol/L sucrose as osmotic sta- bilizer, and the regeneration rate had reached 0.22%. [Conclusion] This study provid- ed valuable support for protoplast fusion, ultraviolet mutation breeding and genetic engineering research.

A New Kind of Conjugate-nested Central Configurations in Consisted of One Regular Tetrahedron and One Regular Octahedron

A new case configuration in R^3, the conjugate-nest consisted of one regular tetrahedron and one regular octahedron is discussed. If the configuration is a central configuration, then all masses of outside layer are equivalent, the masses of inside layer are also equivalent. At the same time the following relation between ρ（r =√3/3ρ is the radius ratio of the sizes） and mass ratio τ=~↑m/m must be satisfied τ=~↑m/m=ρ（ρ＋3）（3＋2ρ＋ρ^2）^-3/2＋ρ（-ρ＋3）（3-2ρ＋ρ^2）^-3/2-4.2^-3/2ρ^-2-^-1ρ^-2/2（1＋ρ）（3＋2ρ＋ρ^2）^-3/2＋2（ρ-1）（3-2ρ＋ρ^2）^-3/2-4（2√2）^-3ρ, and for any mass ratio τ, when mass ratio r is in the open interval （0, 0.03871633950 ... ）, there exist three central configuration solutions（the initial configuration conditions who imply hamagraphic solutions） corresponding radius ratios are r1, r2, and r3, two of them in the interval （2.639300779… , ＋∞） and one is in the interval （0.7379549890…, 1.490942703… ）. when mass ratio τ is in the open interval （130.8164950… , ＋∞）, in the same way there have three corresponding radius ratios, two of them in the interval （0, 0.4211584789... ） and one is in the interval （0.7379549890…, 1.490942703…）. When mass ratio τ is in the open interval （0.03871633950…, 130.8164950…）, there has only one solution r in the interval （0.7379549890…, 1.490942703… ）.

Stepwise multiple regressions application in liposome orthogonal experiments

Aim New statistical method was applied in data analysis of orthogonal experiments to optimize the preparation of liposome. Method Particle size, zeta potential, encapsulation efficiency and physical stability of liposomes were selected by orthogonal design as evaluating indicators. Through three statistical methods （direct observation, variance analysis and stepwise multiple regression）, the optimized preparing conditions were acquired and validated by experiment. Results All of the four indicators were different by these analyses. The validation experiments indicated that the optimized conditions by stepwise multiple regressions were better than that by traditional analysis. Conclusion Experiment results suggested that multiple regressions could avoid the weakness of direct observation and variance analysis, but more work should be done in preparing liposomes.

Positive Solutions of p-Laplacian Functional Difference Equations

In this paper, the author studies the boundary value problems for a p-Laplacian functional difference equation. By using a fixed point theorem in cones, sufficient conditions are established for the existence of the positive solutions.

Deformation and densification behavior of discrete media filled thin-walled tubes during forward extrusion

Discrete media filled thin-walled hollow profiles are frequently used as integer structures for special purpose, e.g., in certain materials processing or architectural components. To understand the deformation of such composite structures which is a complicate mechanics process, involving coupled elastic-plastic deformation of dense metal, compaction of particle and interaction between the filler and the wall, the forward extrusion of Al 6061 tubes filled with various particles was studied. The analysis regarding internal volume variation of round tubes during forward extrusion indicates that with the diameter reduction the volume of tubes decreases commonly. The cavity shrinkage brings about triaxial pressure on the filler, resulted in compaction and densification of it. Loose powders filling leads to higher extrusion load. Due to dissimilar migration behaviors of the particles, the load?stroke curves of the tubes filled with fine powders and coarse balls are quite different. Small Lankford value of the tube wall material leads to higher hydrostatic pressure of the filler and then more powders are compacted.