屈学与湘学

湘学就是在湘域长期沉积的文化精粹和学术传统。屈原是"湘"的最先表述者,是湘学中迁谪文学的开创者,也是湘学中忧文化、求索文化、独醒文化的精神始祖。屈原为湘文明作出了重大贡献。屈学奠定了千年湘学传统的基础。

古典屈学中屈原人格研究与现代屈学人格理论

自汉初迄清季,历代学者虽没有用“人格”一词来评论屈原,但对其人的性格、气质、能力、品行等多有阐发,并集中在忠君爱国的伦理道德层面。这些感发式的阐述,包含了“人格”的一些方面,是对屈原人格不自觉的局部揭示。以人格心理学理论观照,屈原赍志以殁,是历史必然条件下其人格合乎逻辑的推衍,是他对人生积极探索之后的必然选择。

当代屈学考信录

对洪湛侯、何新、姜亮夫、姜昆武、吕晴飞、张子伟、蒋天枢等学者论著中的若干误差进行纠正或评说。

一部屈学研究的新成果——读罗敏中的《屈骚与宋代爱国文学》有感

罗敏中先生著作《屈骚与宋代爱国文学》在立意、研究方法与创作等方面都有独到之处,是屈学研究的新成果。

李中华屈学研究的创新思维

屈原是我国伟大的爱国诗人,其作品蕴涵丰富,隽永深邃,历为学术界研究的重点。但由于时代社会状况、学术思潮,以及文人心态的差异,发掘的思想资源各有不同。李中华教授则从楚辞的文化内涵和传播方面入手,以创新思维揭示出屈原“美政”追求的思想根源,道出了“求索”的真谛。本文从其创新思维的起源、发展,以及内容和实施等方面进行评说,并提出了屈学研究的有关问题。

评《汉寿屈原故乡新证》

张中一所著《汉寿屈原故乡新证》,是在总结古今屈学研究基础上,以先秦金文考释为突破口,重新破译屈原作品,以12个专题、数十万字、多视角、全方位提出了"汉寿屈原故乡"新体系。

BUCKLING ANALYSIS OF WOVEN FABRIC UNDER SIMPLE SHEAR IN WARP DIRECTION

Buckling of a woven fabric is analyzed in this paper when it is subjected to a simple shear in warp direction.The equation to determine the buckling direction (buckling wave direction) is obtained and it is found that the buckling direction is related to the critical amount of shear.It is shown that the out-of-plane buckling of fabric is possible and only a flexural buckling mode can exist.The buckling condition for flexural mode is obtained and the curve for that is illustrated.

Plastic yielding of NiTi shape memory alloy under local canning compression

As a new attempt, local canning compression was applied in order to implement large plastic deformation of nickel-titanium shape memory alloy （NiTi SMA） at room temperature. The plastic mechanics of local canning compression of NiTi SMA was analyzed according to the slab method as the well as plastic yield criterion. Transmission electron microscopy （TEM）, high resolution transmission electron microscopy （HRTEM） and scanning electron microscopy （SEM） were used to study the microstructural evolution as well as deformation behavior of NiTi samples under local canning compression. Increasing the hydrostatic pressure with the increase in the outer diameters of the steel cans is responsible for suppressing the initiation and growth of the micro-cracks, which contributes to enhancing the plasticity ofNiTi SMA and avoiding the occurrence of brittle fracture. Plastic deformation of NiTi SMA under a three-dimensional compressive stress state meets von-Mises yield criterion at the true strains ranging from about 0.15 to 0.50, while in the case of larger plastic strain, von-Mises yield criterion is unable to be met since the amorphous phase arises in the deformed NiTi sample.

Effect of composition and sintering temperature on mechanical properties of ZrO_2 particulate-reinforced titanium-matrix composite

The titanium-based composites were synthesized by powder metallurgy method. The effects of composition and sintering temperature on the microstructure and properties of the titanium-based composites were investigated by X-ray diffraction, optical microscopy, scanning electron microscopy and mechanical properties tests. The results demonstrate that adding ZrO2 particles can improve the mechanical properties of powder metallurgy （P/M） titanium-based composites. The Ti composite with 4% （mole fraction） ZrO2 sintered at 1100 °C for 4 h shows an appropriate mechanical property with a relative density of 93.9%, a compressive strength of 1380 MPa （570 MPa higher than pure Ti） and good plasticity （an ultimate strain above 24%）.

New Tannins from Lythrum Salicaria L

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Effect of Ce content on mechanical properties of Ce/Cr coated open-cell Ni-Cr-Fe alloy foams

The Ce/Cr coating was homogenously deposited onto the reticulated open-cell Ni?Cr?Fe alloy foam by the pack cementation process.The mechanical properties of the Ce/Cr coated alloy foams were investigated by the quasi-static compression test.Simultaneously,the deformation and failure mechanisms of Ce/Cr coated alloy foams were discussed.The results show that the adding amount of CeO2powders influences the mechanical properties of the Ce/Cr coated alloy foams.Despite an increase in density as compared to the uncoated foams,the Ce/Cr coated foams exhibit improvement in both yield strength and energy-absorption performance.Especially,the energy-absorption performance of2%Ce/Cr(mass fraction)coated alloy foam is averagely1.9times as high as that of the bare Ni?Cr?Fe alloy foam.In addition,the mechanical properties of the Ce/Cr coated alloy foams increase with the increase of strain rate.The distortion and cracking are mainly the deformation behavior of the Ce/Cr coated alloy foam,confirmed by SEM images.

A New Nonlinear Yield Criterion

Many experimental results show that a wide class of ductile materials obey often nonlinear behavior, thus it is important to propose a nonlinear criterion describing nonlinear behavior of ductile material. A new nonlinear yield criterion was proposed which gives a series of new failure criteria, establishes a relationship among various failure criteria, and encompasses previous yield criteria as special cases or approximations. The criterion is capable of being expressed in a simple mathematical expression and through a particular physical concept, it also agree with some experimental data. It may therefore serve as a possible admissible isotropic yield criterion.

Wind tunnel test and numerical simulation of wind pressure on a high-rise building

We carried out a wind tunnel test to measure cladding loads for a high-rise building of 295 m in height, which would be located in the business center of Chongqing Municipality, P. R. China. The rigid model was used to determine fluctuating local pressures on the exterior surfaces of the building. The wind tunnel test results show the cr/tical zone of wind pressures on building surfaces in both standalone and interference conditions. The computational fluid dynamics （CFD） was conducted by using the FLUENT Code to compare with the wind tunnel test results, and the steady three-dimensional turbulent flow with Realizable k-ε as a turbulence model was used. The CFD results are agree with the wind tunnel test results in regards to distributions of wind pressures over a high-rise building＇s surfaces.

Anisotropic tensile behavior and related yield point phenomena in annealed ultrafine-grained pure aluminum

It is found that tensile flow curves of samples of annealed ultrafine-grained aluminum AA1090 show the development of a yield point and a significant mechanical anisotropy.To rationalize the anisotropic tensile behavior,the orientation data of the annealed material were measured using electron backscatter microscopy.It is found that the inferior mechanical properties of samples tested at 45°to the rolling direction may be attributed to a strong rolling texture effect and that the anisotropic magnitude of the yield drop may be related to the proportion of grains with soft orientations(defined as those with Schmid factor greater than 0.45)in the sample.Additionally,it is found that the anisotropy in tensile ductility is in general agreement with a Considère criterion analysis and that the mechanical anisotropy in the samples is only partly explained by the crystallographic texture,where microstructural anisotropy may also play a role.

FINITE ELEMENT ANALYSIS OF CONCRETE BASED ON TWO SURFACE ELASTOPLASTIC MODEL

This paper presents finite element formulas based on two Surface elastoplastic yielding model. The study also discusses the numerical procedures and develops the corresponding software. These formulas have provided accurate elastoplastic method for analysing concrete, rock and soil like materials.

Compatibility of the Support System Consisting of Yielding Elements and Shotcrete Lining in Highly Faulted Grounds

The design procedure is made for a mine shaft where permanent underground facilities are interconnected. The highly faulted grounds were identified using empirical and semi-empirical theories. Furthermore, the behavior types are presented. This paper presents excavation and support methods in such ground conditions and the calculations results show that the installation of the yielding elements have an effect on support elements and prevent shotcrete damage during the curing stage. Different numerical analyses carried out showed that, with the yielding elements installed, the total displacements increase but the final axial force reduces, and therefore, the characteristic compressive strength of shotcrete is not exceeded. The calculation results of ground loads and displacements on the designed support system are presented with a 3D numerical geo-mechanical model adopted for highly faulted ground surrounding deeper complex underground structures.

Two alkaloids as α-amylase inhibitors: enzyme kinetics and molecular modeling investigations

In the present study, we studied the inhibitory effects of chelidonine and rutaecarpin on porcine pancreatic a-amylase （PPA） catalyzed hydrolysis using 2-chloro-4-nitrophenyl-4-O-β-D-galactopyranosylmaltoside （Gal-G2-α-CNP）. We, for the first time, provided kinetic report and detailed inhibitory effects of both compounds on PPA. Lineweaver-Burk plot revealed that the inhibition was a mixed-noncompetitive type, and only one molecule of inhibitor bound to the enzyme or to the enzyme-substrate complex. Kinetic constants calculated from secondary plots were in millimole range. Dissociation constants of enzyme-inhibitor complex （KEI） were 0.9 mM and 3.5 mM, respectively. Moreover, dissociation constants of enzyme-inhibitor-substrate complex （KESI） were 0.04 mM and 0.31 mM, respectively. These data indicated that the inhibition was more inclined to competitive to Gal-G2-α-CNP hydrolysis. Further molecular docking study manifested that hydrogen bonding formed between acarbose and aspartic acid （Asp300）, histidine （His305） and glycine （Gly3-6）, while hydrogen bonding was observed between chelidonine and glutamic acid （Glu233）, lysine （Lys200） and His305. In addition, rutaecarpine had only one hydrogen bond with Lys200. Our data indicated that chelidonine and rutaecarpine were two promising drug candidates, and chelidonine possessed stronger inhibitory effect compared with rutaecarpine.

Repair of flexor tendon defects of rabbit with tissue engineering method

Objective: To repair rabbit tendon defects with tissue engineering method. Methods: The third passage of fetal skin fibroblast cells was labeled with 5 bromo 2 deoxyuridine (Brdu) and then seeded on human amnion extracellular matrix ( HA ECM ). Using 1 cm long Achilles tendon defects as repairing models in the experimental group, tendon defects were core bridged with polydioxanone (PDS) and then capsulated with the complex of fibroblasts HA ECM . In the control group I, defective tendons were sutured with PDS following the former procedure and capsulated with HA ECM (without fibroblasts). In the control group II, only PDS was applied to connect the defective tendons. Gross examination, light microscopy, scanning electronmicroscopy and biomechanical measurement of the repaired tendons were respectively performed at postoperative 1, 2, 3 month as well as immunohistochemical examination. Results: The optimal cell concentration for seeding fibroblasts was 3.5 ×10 6 cells/ml. Cells grew well and radiated or paralleled on HA ECM . Immunohistochemistry showed that the labeled seed fibroblasts played an important role in tendonization. The results of light microscopy, electron microscopy, and biomechanical assessment suggested that the rate and quality of tendonization in the experimental group was superior to those of the control group I and II. The tensile strength in the experimental group was the greatest, the next was in the control group I, and the worst in the control group II (P< 0.05 ). Conclusions: HA ECM is the excellent carrier for fibroblasts. Fibroblasts HA ECM complex has the capability to repair tendon defect and to tendonize with rapid rate and good performance three months after operation. Its tensile strength is 81.8 % of that of normal tendon.

Yielding behavior of copper nanowire in the presence of vacancies

In the present research,the measurement fluctuations of mechanical properties in nanowires (NWs) are investigated by using the molecular dynamics simulation.The large numbers of simulations are performed to study the yield behaviors of the NWs.The results have shown that the yield behavior of the smaller diameter NW is more sensitive to the presence of vacancies,and the dispersion of the measured mechanical properties for the small scale NW is larger than that for the large scale NW.Present results have also shown that vacancies escape from the bulk to the free surfaces as a result of high stress applied at the small scale systems similar to the dislocation starvation phenomenon observed in the compression test of nano-pillars,and dislocation nucleation induced by surface defect occurs after the vacancy reaches free surface leading to lower yield strength.Moreover,the strong surface vacancy interactions at the nanoscale level are also investigated.

Combined torsional buckling of double-walled carbon nanotubes with axial load in the multi-field coupled condition

The present study has theoretically investigated the combined torsional buckling of double-walled carbon nanotubes (DWCNTs) with axial load in the multi-field coupled condition. The effects of torsion, axial load, thermal-electrical change, surrounding elastic medium and the Van der Waals forces are all taken into consideration. The governing equation of buckling for CNTs subjected to thermo-electro-mechanical loadings has been established based on an elastic shell model of continuum mechanics. Reasonable simplifications are made to get the explicit expression of the critical buckling shear stress of DWCNTs, and numerical experiments are conducted for further research. It is shown that under certain electric and temperature field the critical buckling shear stress of DWCNTs only depends on the wave number of buckling modes. On the other hand, all the related impact factors have enormous influence on the critical buckling shear stress under a certain buckling mode. The critical buckling shear stress changes linearly with the axial-to-shear stress ratio, as well as the thermal and electric change. Axial compression tends to make DWCNTs unstable, while axial tension benefits the buckling stability. The critical buckling shear stress is directly proportional to the applied voltage. At room or lower temperature, the critical shear stress for infinitesimal buckling increases as the temperature change increases, while it decreases at a higher temperature. The conclusions are useful for the design of nano-structures related to the buckling stability of DWCNTs.