形合理、态合情——浙江大学管理学院大楼设计解读

建筑的形和态是建筑的一体两面,建筑设计中除了注重客观的"形"还要关照主观的"态"。浙江大学管理学院大楼的设计从规划理性、布局理性、功能理性方面对形态背后的理性逻辑做了综合分析,并从书院情思、求是情怀、水乡情愫方面就形态设计背后的情感关照做了适当回应,以追求达到"形合理、态合情"的设计目标。

易滑地层顺层边坡合理坡形UDEC模拟分析

针对重庆三峡地区易滑地层地质特性,充分收集和分析前人的研究资料及成果,运用通用颗粒离散元程序(UDEC)建立三峡库区顺层三级边坡模型,模拟过程中主要考虑层面倾角、碎落台宽度以及粘聚力等参数对边坡稳定性的影响,分析模拟计算得出的不同参数组合下的安全系数,提出易滑地层三级顺层边坡合理放坡坡形。

Microstructural evolution and deformation mechanisms of superplastic aluminium alloys:A review

Aluminium alloy is one of the earliest and most widely used superplastic materials.The objective of this work is to review the scientific advances in superplastic Al alloys.Particularly,the emphasis is placed on the microstructural evolution and deformation mechanisms of Al alloys during superplastic deformation.The evolution of grain structure,texture,secondary phase,and cavities during superplastic flow in typical superplastic Al alloys is discussed in detail.The quantitative evaluation of different deformation mechanisms based on the focus ion beam(FIB)-assisted surface study provides new insights into the superplasticity of Al alloys.The main features,such as grain boundary sliding,intragranular dislocation slip,and diffusion creep can be observed intuitively and analyzed quantitatively.This study provides some reference for the research of superplastic deformation mechanism and the development of superplastic Al alloys.

Deformation mechanism and softening effect of extruded AZ31 magnesium alloy sheet at moderate temperatures

The flow stress behavior of extruded AZ31 magnesium alloy sheet was investigated by means of compression tests at temperatures between 473 and 523 K and strain rates ranging from 0.001 to 1.0 s-1. The deformation activation energy of the sheet in extrusion direction （ED） was calculated, and the relationship between the softening effect and deformation mechanism was elucidated by optical microscopy and transmission electron microscopy. The results show that when the extruded AZ31 magnesium alloy samples were compressed at moderate temperatures in ED direction, the deformation activation energy is 174.18 kJ/mol, which means that dynamic recrystallization （DRX） is the main softening effect and is controlled by cross slip of thermal active dislocation. Dislocation slip is the main deformation mechanism in moderate-temperature deformation process except twinning. The main DRX effect at moderate temperatures can be considered to be continuous dynamic recrystallization accommodated with twinning DRX.

Microstructural evolution of 2026 aluminum alloy during hot compression and subsequent heat treatment

2026 aluminum alloy was compressed in a temperature range of 300-450 ℃ and strain rate range of 0.01-10 s^-1. The correlation between compression conditions and microstructural evolution after solution and aging heat treatment was investigated. It is found that the recrystallization and precipitation behavior after heat treatment are associated with the temperature compensated strain rate Z value during hot deformation. Under low Z parameter condition, a small quantity of free recrystallized grains are formed, and the well formed subgrains with clean high-angle boundaries and coarse precipitates seem to be remained during heat treatment. Under high Z parameter condition, a large number of fine equiaxed recrystallized grains are produced, and a high dislocation density with poorly developed cellularity and considerable fine dynamic precipitates are replaced by the well formed subgrains and relatively coarse precipitates after heat treatment. The average recrystallized grain size after heat treatment decreases with increasing Z value and a quantitative relation between the average grain size and the Z value is obtained.

Microstructure and texture characterization of superplastic Al-Mg-Li alloy

A novel thermomechanical processing was developed for producing fine grained Al-Mg-Li alloy sheets. The influences of static recrystallization annealing on the grain structure and superplastic behavior were investigated. The results show that the refined microstructure has a variation in the distribution of grain size, shape and texture across the normal direction of the sheet. The surface layer （SL） has fine, nearly equiaxed grains with a rotated cUbeND {001 }（310） orientation, whereas the center layer （CL） has coarse, elongated grains with a portion of a fiber orientation. Increasing static recrystallized temperature results in grain growth in the full thickness, decreasing of grain aspect ratio in the center layer, texture sharpening in the surface layer, but weakening in the center layer as well as decreasing of superplastic elongation. Increasing the annealing temperature also produces an sharpening of the rotated cube {001}（310） component and a decreasing of the a fiber texture in the full thickness of the sheet. The formation mechanisms of recrystallization texture at various temperatures and layers were discussed.

Calculations of rock matrix modulus based on a linear regression relation

The rock matrix bulk modulus or its inverse, the compressive coefficient, is an important input parameter for fluid substitution by the Biot-Gassmann equation in reservoir prediction. However, it is not easy to accurately estimate the bulk modulus by using conventional methods. In this paper, we present a new linear regression equation for calculating the parameter. In order to get this equation, we first derive a simplified Gassmann equation by using a reasonable assumption in which the compressive coefficient of the saturated pore fluid is much greater than the rock matrix, and, second, we use the Eshelby- Walsh relation to replace the equivalent modulus of a dry rock in the Gassmann equation. Results from the rock physics analysis of rock sample from a carbonate area show that rock matrix compressive coefficients calculated with water-saturated and dry rock samples using the linear regression method are very close （their error is less than 1%）. This means the new method is accurate and reliable.

Effects of alloying and deformation on microstructures and properties of Cu-Mg-Te-Y alloys

New copper alloys with high mechanical properties and high electrical conductivity were prepared, and the effects of addition of minor Mg and Y elements on microstructures and properties were studied. The high tensile strength of above 510 MPa, high elongation of 11%and high electrical conductivity of over 63%IACS can be simultaneously obtained in Cu-0.47Mg-0.20Te-0.04Y alloy after deforming and annealing treatment. Effects of purification together with the grain refining by Y and solid-solution strengthening by Mg are appropriate for enhancing mechanical properties and electrical conductivity of the copper alloys.

Effect of thermo-mechanical treatment process on microstructure and mechanical properties of 2A97 Al-Li alloy

2A97 Al-Li alloy was processed by thermo-mechanical treatment at different pre-stretch deformations of 0, 3% and 6%. The microstrucatre observation results reveal that some δ＇ and T1 precipitates are found in a（Al） matrix of 2A97 alloy processed by the heat treatment with no pre-stretch deformation. When the pre-stretch deformation is 3% and 6%, respectively, amounts of tiny T1 and a few of S＇ precipitates precipitates are observed in the microstructures of 2A97 alloy. The tensile test results show that the tensile properties of 2A97 alloys are improved via thermo-mechanical treatment. When the pre-stretch deformation is from 0, 3% to 6%, the ultimate tensile strength values of the 2A97 alloys increase gradually from 447.7, 516.5 to 534.3 MPa, and the elongations decrease from 17.6%, 12.8% to 10.2%, respectively. Moreover, with increasing pre-stretch deformation amount from 0 to 6%, the in-plane anisotropy value of 2A97 alloys becomes more obvious.

Formability and strengthening mechanism of AA6061 tubular components under solid granule medium internal high pressure forming

A new technological process of tube forming was developed, namely solution treatment → granule medium internal high pressure forming → artificial aging. During this process, the mechanical properties of AA6061 tube can be adjusted by heat treatment to satisfy the process requirements and the processing method can also be realized by granule medium internal high pressure forming technology with the features of convenient implementation, low requirement to equipment and flexible design in product. Results show that, at a solution temperature of 560 ℃ and time of 120 min, the elongation of AA6061 increases by 313%, but the strength and the hardness dramatically decrease. At an aging temperature of 180 ℃ and time of 360 min, the strength and hardness of AA6061 alloy are recovered to the values of the as-received alloy. The maximum expansion ratio（MER） of AA6061 tube increases by 25.5% and the material properties of formed tube reach the performances of raw material.

Effects of T9I6 thermo-mechanical process on microstructure, mechanical properties and ballistic resistance of 2519A aluminum alloy

The effects of T916 thermo-mechanical process on microstructures, mechanical properties and ballistic resistance of 2519A aluminum alloy were investigated by optical microscopy （OM）, transmission electron microscopy （TEM）, tensile tests and ballistic resistance test. After T916 treatment, the yield strength, tensile strength and elongation rate of 2519A aluminum alloy reach 501 MPa, 540 MPa and 14%, respectively. And the ballistic limit velocity of 2519A-T916 alloy （30 mm in thickness） is 715 rn/s. The microstructure varies near the sidewalls of crater. The interrupted ageing contributes to these excellent properties of the alloy. During T916 process, the precipitation of Guinier Preston （GP） zone is finer and denser during the interrupted ageing, thus resulting in well precipitated strengthening phase.

Theoretical prediction of forming limit diagram of AZ31 magnesium alloy sheet at warm temperatures

A theoretical prediction on forming limit diagram（FLD） of AZ31 magnesium alloy sheet was developed at warm temperatures based on the M-K theory. Two different yield criteria of von Mises and Hill＇48 were applied in this model. Mechanical properties of AZ31 magnesium alloy used in the prediction were obtained by uniaxial tensile tests and the Fields-Backofen equation was incorporated in the analysis. In addition, experimental FLDs of AZ31 were acquired by conducting rigid die swell test at different temperatures to verify the prediction. It is demonstrated from a comparison between the predicted and the experimental FLDs at 473 K and 523 K that the predicted results are influenced by the type of yield criterion used in the calculation, especially at lower temperatures. Furthermore, a better agreement between the predicted results and experimental data for AZ31 magnesium alloy sheet at warm temperatures was obtained when Hill＇48 yield criterion was applied.

Microstructural evolution during solution treatment of thixoformed AM60B Mg alloy

The microstructural evolution and kinetic characteristics were studied during solution treatment of AM60B Mg alloy prepared by thixoforming. The results indicate that the microstructural evolution includes two stages： the first stage involves rapid dissolution of eutectic β （Mg 17 Al 12 ） phase, homogenization and coarsening, and the second stage is regarded as normal grain growth consisting of primary α-Mg particles （primary particles） and secondary α-Mg grains （secondary grains）. In the first stage, the dissolution completes in a quite short time because the fine β phase can quickly dissolve into the small-sized secondary grains. The homogenization of Al element needs relatively long time. Simultaneously, the microstructure morphology and average grain size obviously change. The first stage sustains approximately 1 h when it is solutionized at 395 ℃ Comparatively, the second stage needs very long time and the microstructure evolves quite slowly as a result of low Al content gradient and thus low diffusivity of Al element after the homogenization of the first stage. The growth model of primary particles obeys power function while that of the secondary grains follows the traditional growth equation in the first stage. In the second stage, both of the primary particles and secondary grains behave a same model controlled by diffusion along grain boundaries and through crystal lattice.

Mechanical properties of Mg-6Gd-1Y-0.5Zr alloy processed by low temperature thermo-mechanical treatment

An as-solution treated Mg-6Gd-1Y-0.4Zr alloy was processed by low temperature thermo-mechanical treatments （LT-TMT）, including cold tension with various strains followed by aging at 200 °C to peak hardness. The results show that the precipitation kinetics of the alloy experienced LT-TMT is greatly accelerated and the aging time to peak hardness is greatly decreased with increasing tensile strain. The tensile yield strength, ultimate tensile strength and elongation at room temperature of the alloy after cold tension with strain of 10% and peak aging at 200 °C are 251 MPa, 296 MPa and 8%, respectively, which are superior to the commercial heat-resistant WE54 alloy, although the latter has a higher rare earth element content.

Effects of Silicon at Different Concentrations on Morphology and Photosynthetic Physiological Mechanism of Japonica Rice

[Objective] The aim was to explore effects of silicon at different concentrations on morphology and photosynthetic physiological mechanism of japonica rice. [Method] Seedlings of japonica rice were treated with silicon at different concentrations （0, 30, 80, 130 and 180 mg/L of sodium silicate）; silicon contents were measured with Molybdenum blue spectrophotometric method in root, stem and leaf; plant height, root length and number in different treatment groups were measured with tools; chlorophyll a and b, and a/b in leaf and stem of rice in different groups were measured. [Result] Silicon contents in vegetative organs were as follows： stem〉leaf〉 root; when silicon was 80 mg/L, japonica ecotype was shortest; when silicon was 30 mg/L, root length of the rice was shortest and root number was least; when silicon was 30 mg/L, contents of chlorophyll a and b were highest and chlorophyll a/b achieved the peak when silicon was 80 mg/L. [Conclusion] Silicon at proper concen- tration would improve lodging-resistance and efficiency of photosynthesis, further enhancing yield of japonica rice.

Si phase morphology and mechanical properties of ZL107 Al alloy improved by La modification and heat treatment

The phase morphology evolution during the solid solution treatment and then artificial aging of the La-modified ZL107 Al alloy was studied. The results show that when the solid solution was held at 560 ℃ for 6 h, only partial Si phase dissolved into the matrix; however, the precipitation also occurred during the artificial aging process. The precipitation process in Al-Si alloys with or without La-modification was compared. After modification and heat treatment, the mechanical properties of the alloy were greatly enhanced, due to the modification and uniform distribution of Si phase.

Selective synthesis and shape-dependent photoluminescence properties of (Y_(0.95)Eu_(0.05))_2O_3 submicron spheres and microplates

Red-emission （Y0.95Eu0.05）2O3 submicron spheres and microplates were selectively obtained via hydrothermal precursor synthesis （150 °C, 12 h） followed by calcination at 1000 °C. Characterizations of the products were carried out by combined means of XRD, FT-IR, FE-SEM and PL analysis. The precursors could be modulated from basic-carbonate submicron spheres to normal carbonate microplates by increasing the molar ratio of urea to Y＋Eu from 10 to 40-100. The resultant oxides largely retain their respective precursor morphologies at 1000 °C, but morphology confined crystal growth was observed for the microplates, yielding more enhanced exposure of the （400） facets. Both the （Y0.95Eu0.05）2O3 spheres and microplates exhibit nearly identical positions of the PL bands and similar asymmetry factors of luminescence [I（5D0→7F2）/I（5D0→7F1）, ～11] under 250 nm excitation, but the microplates show a significantly strong red emission at ～613 nm （ ～1.33 times that of the spheres） owing to their larger particle size and denser packing of primary phosphor crystallites.

Polymerization Mechanism of α-Linear Olefin

The density functional theory on the level of B3LYP/6-31G was empolyed to study the chain growth mechanism in polymerization process of α-linear olefin in TiCl3/AlEt2Cl catalytic system to synthesize drag reduction agent. Full parameter optimization without symmetry restrictions for reactants, products, the possible transition states, and intermediates was calculated. Vibration frequency was analyzed for all of stagnation points on the potential energy surface at the same theoretical level. The internal reaction coordinate was calculated from the transition states to reactants and products respectively. The results showed as flloes： （i） Coordination compounds were formed on the optimum configuration of TiCl3/AlEt2Cl.（ii） The transition states were formed. The energy di？erence between transition states and the coordination compounds was 40.687 kJ/mol. （iii） Double bond opened and Ti-C（4） bond fractured, and the polymerization was completed. The calculation results also showed that the chain growth mechanism did not essentially change with the increase of carbon atom number of α-linear olefin. From the relationship between polymerization activation energy and carbon atom number of the α-linear olefin, it can be seen that the α-linear olefin monomers with 6-10 carbon atoms had low activation energy and wide range. It was optimum to synthesize drag reduction agent by polymerization.

Effect of heat treatment on tensile deformation behavior of Ni-Co film/Fe substrate systems

The effects of heat treatment on microstructure and tension property of Ni-Co film/Fe substrate systems were investigated. The deformation and fracture morphologies of Ni-Co films/Fe substrate systems were studied by in-situ scanning electron microscopy（in-situ SEM）before and after heat treatment.The results show that a Ni-Co/Fe diffusion layer appears between the film and substrate after heat treatment;the elongation of film/substrate system increases with increasing the heat treatment temperature. Both the strength and ductility of the film/substrate system are preferable when heat treatment temperature is 650 o C,meanwhile the maximum elongation is up to 46%.During tensile deformation,the deformation behaviors of Ni-Co film/Fe substrate are quite different before and after heat treatment.The samples after heat treatment went through the progress of holes’emergence,growth and extension,whereas the samples without heat treatment accompanied with no holes,just cracked instead,showing that appropriate heat treatment is helpful to improve the toughness of material,and mechanical properties.

Recent advances of electromagnetic interference shielding Mg matrix materials and their processings:A review

In terms of lightweight electromagnetic interference(EMI)shielding structural materials,Mg matrix materials have proven to be the best,due to their exciting properties(e.g.low density,high specific strength,good electrical conductivity and excellent EMI shielding properties)and their wide range of applications in lightweighting in electronics,automotive and aerospace industries.Through processing,such as alloying,heat treatment,plastic deformation and composite processing,Mg matrix materials can be obtained with tailorable properties which can play a key role in designing materials for EMI shielding.This work introduces an overview of the research on the EMI shielding properties of Mg matrix materials as well as their EMI shielding mechanisms over the past few decades,focused on the influence of alloying,heat treatment,plastic deformation and composite processing for the EMI shielding properties of Mg matrix materials.At the end,conclusions and future perspectives are provided.