结晶器电磁搅拌电流对Φ650mm大圆坯内部质量的影响

通过铸坯低倍组织宏观检验方法和金属原位统计分布分析技术，以钢厂生产的35钢（0．35％C）为例，研究了结晶器电磁搅拌电流（200～450A，3Hz）对φ650mm大断面连铸圆坯等轴晶率、致密度和碳偏析度的影响。结果表明，搅拌频率3Hz时，结晶器电磁搅拌电流由200A增加至450A时，等轴晶率由24．2％提高至56．8％，同时铸坯各区域致密度呈现逐渐增大的趋势，其中铸坯中心区域致密度增加明显，由0．8649增至0．9376；随着搅拌电流的增加，铸坯碳偏析度呈现逐渐减轻的趋势。综合考虑各因素，当结晶器电磁搅拌电流为450A，频率为3Hz，铸坯等轴晶比例最大，铸坯内部质量最好。

Simulated and experimental investigation on discontinuous dynamic recrystallization of a near-α TA15 titanium alloy during isothermal hot compression in βsingle-phase field

A cellular automaton（CA） modeling of discontinuous dynamic recrystallization（DDRX） of a near-α Ti-6Al-2Zr-1Mo-1V（TA15） isothermally compressed in the β single phase field was presented.In the CA model,nucleation of the β-DDRX and the growth of recrystallized grains（re-grains） were considered and visibly simulated by the CA model.The driving force of re-grain growth was provided by dislocation density accumulating around the grain boundaries.To verify the CA model,the predicted flow stress by the CA model was compared with the experimental data.The comparison showed that the average relative errors were10.2%,10.1%and 6%,respectively,at 1.0,0.1 and 0.01 s^-1 of 1020 ℃,and were 10.2%,11.35%and 7.5%,respectively,at 1.0,0.1and 0.01 s^-1 of 1050 ℃.The CA model was further applied to predicting the average growth rate,average re-grain size and recrystallization kinetics.The simulated results showed that the average growth rate increases with the increasing strain rate or temperature,while the re-grain size increases with the decreasing strain rate;the volume fraction of recrystallization decreases with the increasing strain rate or decreasing temperature.

Cyanide-free silver electroplating process in thiosulfate bath and microstructure analysis of Ag coatings

Cyanide-free silver electroplating was conducted in thiosulfate baths containing AgNO3 and AgBr major salts, respectively. The effects of major salt content and current density on surface quality, deposition rate and microhardness of Ag coatings were investigated. The optimized electroplating parameters were established. The adhesion strength of Ag coating on Cu substrate was evaluated and the grain size of Ag coating was measured under optimized electroplating parameters. The optimized AgNO3 content is 40 g/L with current density of 0.25 A/dm2. The deposited bright, smooth, and well adhered Ag coating had nanocrystalline grains with mean size of 35 nm. The optimized AgBr content was 30 g/L with current density of 0.20 A/dm2. The resultant Ag coating had nanocrystalline grains with mean size of 55 nm. Compared with the bath containing AgBr main salt, the bath containing AgNO3 main salt had a wider current density range, and corresponding Ag coating had a higher microhardness and a smaller grain size.

X-ray and DFT Study of Glaucocalyxin A Compound with Cytotoxic Activity

The title compound glaucocalyxin A （1） （Ta,14β-dihydroxy-ent-kaur-16-en-3,15-dione） iso- lated from the leaves of isodon excisoides was characterized by IR, 1H NMR, 13C NMR, 1H-1H COSY, HMQC, HMBC, and EIMS, and its crystal structure was determined by singlecrystal X-ray diffraction. The X-ray crystal structure revealed that the molecular backbone of the chosen crystal is a tetracyclic system, including three six-membered rings and a five- membered ring, and the three six-membered rings are in a chair-like conformation. The five-membered ring adopts a twisted envelope-like conformation, and its geometrical param- eters were compared with theoretical calculations at the B3LYP and HF level of theory. The molecules form extensive networks through the intra- and intermolecular hydrogen bonds. The experimental NMR data were interpreted with the aid of magnetic shielding constant calculations, by means of the GIAO （gauge-Including atomic orbitals） method. Calculated and experimental results were compared with a satisfactory level of agreement. Molecular electrostatic potential map was used in an attempt to identify key features of the diterpenoid glaucocalyxin A that is necessary for its activity. Calculations of molecular electrostatic po- tential and stabilization energies suggest that the protonation of glaucocalyxin A will be able to occur on carbonyl oxygen atoms.

一种低感度、高性能的新型炸药FOX-7

FOX-7或1.1-二氨基-2．2-二硝基乙烯是一种低感度和高性能的新型炸药。本文报道了它的合成，感度(摩擦落锤和SSGT)，热稳定性和相容性，以及它的结晶密度，ρ=1．885g／cm^3(粉末X-射线)和它的生成热。AHf=-32kcal／mole(弹式量热法)。相容性的测量用微热量计进行测量，并且显示与聚合物，增塑剂和二异氰酸盐的相容性极佳。用DSC测量活化能(Ea=58kcal／mole)用伍德合金浴测量点火温度(Tign=205℃)。为了说明根据实验观测到的相容性和感度的数据。我们进行了量子力学计算(从B3LYP／6-3l+C**级开始)。量子力学(QM)的计算也与X-射线测定的长度和角度相同。用热化学符号(Cheetah 1．40)和实验测得的密度和生成热值计算爆速和爆压(DCJ=8870m／s，pCJ=34．0GPa)。

Dislocation density model and microstructure of 7A85 aluminum alloy during thermal deformation

The microstructure evolution of 7A85 aluminum alloy at the conditions of strain rate(0.001−1 s^(−1))and deformation temperature(250−450°C)was studied by optical microscopy(OM)and electron back scattering diffraction(EBSD).Based on the K-M dislocation density model,a two-stage K-M dislocation density model of 7A85 aluminum alloy was established.The results reveal that dynamic recovery(DRV)and dynamic recrystallization(DRX)are the main mechanisms of microstructure evolution during thermal deformation of 7A85 aluminum alloy.350−400°C is the transformation zone from dynamic recovery to dynamic recrystallization.At low temperature(≤350°C),DRV is the main mechanism,while DRX mostly occurs at high temperature(≥400°C).At this point,the sensitivity of microstructure evolution to temperature is relatively high.As the temperature increased,the average misorientation angle(θˉ_(c))increased significantly,ranging from 0.93°to 7.13°.Meanwhile,the f_(LAGBs) decreased with the highest decrease of 24%.

Preparation of spherical cobalt carbonate powder with high tap density

Spherical cobalt carbonate with high tap density, good crystallization and uniform particle size was prepared by controlled chemical crystal method using cobalt chloride and ammonium bicarbonate as cobalt source and precipitator. The effects of pH value and reaction time on crystallization and physical properties of cobalt carbonate were studied. The results show that the key factors influencing the preparation process of spherical cobalt carbonate with high tap density and good crystallization are how to control pH value (7.25±0.05) and keep some reaction time (about 10 h). Co4O3 was prepared by sintering spherical morphology CoCO3 samples at varied temperatures. The results show that as the decomposition temperature increases, the as-obtained Co4O3 products with porous structure transform into polyhedral structure with glazed surface, and simultaneously the cobalt content and tap density increase. However, the specific surface area shows a trend of decrease.

Syntheses and calculation of( E)-4-chloro-4'-ethoxystilbene and( E)-4,4'-dichlorostilbene

（E） -4-chloro-4＇ -ethoxystilbene （2a） and （E） -4, 4＇ - dichlorostilbene （2b） were synthesized by the Witting-Homer reaction. The crystals of 2a and 2b were prepared through solvent evaporation and characterized by the single-crystal X- ray diffraction. Molecular structure analysis confirms the E- configuration of C=C bond. The crystal of 2a reveals an orthorhombic and space group Pna21 structure while 2b shows a monoclinic and space group P21/c structure. The electronic structures of 2a and 2b were optimized at B3LYP/6-311 ＋ ＋ G （d, p） level. The Hirshfeld surface and fingerprint plot indicate close O-H and C1-H contacts and π-π stacking in 2a and 2b. Molecular electrostatic potential shows that the O and C1 atoms of 2a and C1 atoms of 2b have the minimum energies and they are more likely to be attacked by electrophiles in reaction. Frontier molecular orbitals analysis demonstrates that the △ELuMO_HOMO of 2a and 2b are 3.85 and 3.91 eV, respectively.

Crystal Structure and Geometry-Optimization Study of N-(2-hydroxy-1-naphthaldene)-4-aminoantipyrine

N-（2-hydroxy-l-naphthaldene）-4-aminoantipyrine has been synthesized. The structure is determined by X-ray diffraction method and elemental analysis. The crystal system belongs to orthorhombic space group P（2）2（1）2（1）. The geometry has been ob- tained from the density functional theory （DFT） method and the B3LYP method employing the 6-31G^＊ basis sets. The calculated results propose that the latter is close to the experimental data. The structural parameters from the theory are close to those of the crystal and the calculated total energy of coordination is -31677.172 eV. The energy of HOMO and LUMO and the energy gap are 5.179 eV, -1.603 eV and 3.577 eV, respectively.

Microstructure homogeneity regulation of 7050 aluminum forgings by surface cumulative plastic deformation

To regulate the microstructure homogeneity of large aluminum structural forgings for aircraft,the surface cumulative plastic deformation was proposed.The microstructure of 7050 aluminum forgings after the surface cumulative plastic deformation was investigated by electron backscatter diffraction(EBSD),transmission electron microscopy(TEM),and X-ray diffraction(XRD).The results showed that the microstructure evolution of 7050 aluminum forgings was more sensitive to the deformation temperature than the strain rate.The dislocation density continued to increase with the decrease of the deformation temperature and the increase of the strain rate.Dislocation density and stored energy were accumulated by the surface cumulative plastic deformation.Besides,a static recrystallization(SRX)model of 7050 aluminum forgings was established.The SRX volume fraction calculated by this model was in good agreement with the experimental results,which indicated that the model could accurately describe the SRX behavior of 7050 aluminum forgings during the surface cumulative plastic deformation.

Fabrication and characterization of amorphous ITO/p-Si heterojunction solar cell

Amorphous indium-tin-oxide(a-ITO) film was deposited by radio-frequency(RF) magnetron sputtering at 180°C substrate temperature on the texturized p-Si wafer to fabricate a-ITO/p-Si heterojunction solar cell.The microstructural,optical and electrical properties of the a-ITO film were characterized by XRD,SEM,XPS,UV-VIS spectrophotometer,four-point probe and Hall effect measurement,respectively.The electrical properties of heterojunction were investigated by I-V measurement,which reveals that the heterojunction shows strong rectifying behavior under a dark condition.The ideality factor and the saturation current density of this diode are 2.26 and 1.58×10-4 A cm-2,respectively.And the value of IF/IR(IF and IR stand for forward and reverse currents,respectively) at 1 V is found to be as high as 21.5.For the a-ITO/p-Si heterojunction solar cell,the a-ITO thin film acts not only as an emitter layer,but also as an anti-reflected coating film.The conversion efficiency of the fabricated a-ITO/p-Si heterojunction cell is approximately 1.1%,under 100 mW cm-2 illumination(AM1.5 condition).And the open-circuit voltage(Voc),short-circuit current density(J SC),filll factor(FF) are 280 mV,9.83 mA cm 2 and 39.9%,respectively.Because the ITO film deposited at low temperature is amorphous,it can effectively reduce the interface states between ITO and p-Si.The barrier height and internal electric field,which is near the surface of p-Si,can effectively be enhanced.Thus we can see the great photovoltaic effect.

Tuning the aggregation structure and electrical property of 2.6-diphenyl-anthracene by the density of octadecyltrichlorosilane

The physical and chemical properties of organic semiconductors are closely related to their aggregation structure. Tuning of aggregation structure and electrical property is important for the application in organic electronics. In this study, a facile way to tune the aggregation structure and electrical property of 2.6-diphenyl-anthracene(DPA) is realized by using the octadecyltrichlorosilane(OTS) modification layer with different density which is fabricated by controlling reaction temperature and time.Compared with low density OTS, DPA forms larger grain size, less grain boundaries, and better molecular ordering on high density OTS surface. As a result, the charge transporting mobility of DPA film on high density OTS surface is about two orders of magnitude higher than that on low density OTS surface. The tunable aggregation structure and electrical property of DPA demonstrated here would be meaningful for the application of DPA in organic electronics.

Photophysical properties of heteroaromatic ring-fused(di)benzosiloles

Benzosiloles fused to heterocycles such as thiophene, benzothiophene, and benzofuran, and indole- and benzosilole-fused dibenzosiloles were prepared by palladium-catalyzed intramolecular coupling of the corresponding 2-（arylsilyl）aryl triflates in good to high yields. Molecular and crystal structures of 5,7-dihydro-5,5,7,7-tetrakis（1-methylethyl）bis[1]benzosilolo-[2,3-b：3＇, 2＇-d]thiophene, 6-methyl-12,12-diisopropyl-12H-indololo[3,2-b][1]silafluorene, and 5,5,11,11-tetraisopropyl-5,11H-benzosilolo[3,2-c]silafluorene were determined by X-ray diffraction analysis. The UV absorption spectra of the （di）benzosilole derivafives in cyclohexane red-shifted when compared to 1,1-diisopropyldibenzosilole, indicating that replacing a benzene ring of dibenzosilole by the heterocycles as well as fusion of indole and benzosilole moieties onto dibenzosilole narrowed the HOMO- LUMO gaps of the n-conjugation system. The thiophene-fused benzosiloles were faintly fluorescent in solution and in the solid state, whereas the dibenzosiloles exhibited luminescence with moderate and high quantum yields in cyclohexane and in microcrystals, respectively. In other words, aggregation-induced emission was observed for the dibenzosiloles. Notably, 5,5,11,1 1- tetraisopropyl-5,11H-benzosilolo[3,2-c]silafluorene in microcrystals exhibited violet fluorescence （λmax = 396 nm） with a quantum yield of 0.70. Density functional theory （DFT） calculations of the prepared （di）benzosiloles were also performed.