Search

Marketing teaching is still largely based on theoretical teaching. This kind of teaching mode is difficult to greatly improve the marketing practice teaching, students’ practical ability, innovative thinking ability, and so on. At the same time, the teaching arrangement of marketing training is not standardized, which makes it difficult to provide effective guidance for students. This paper attempted to reform the traditional teaching methods of marketing courses in universities, and deeply studied the teaching methods of traditional college students’ marketing courses under the background of the network, as well as conducted marketing practice according to two different Internet algorithm marketing strategy models. The experimental data showed that the average teaching quality score of the traditional marketing course teaching mode was only 6.9, while the teaching quality score of the marketing course teaching mode under the Internet background was 8.15; the market share of water heaters under the neural network-based marketing strategy increased by 8.1% within 4 months, while the market share of water heaters under the data mining-based marketing strategy decreased by 4.8%. Therefore, it can be seen that the marketing course teaching mode under the Internet background can improve the teaching quality, and the marketing effect of the neural network-based marketing strategy is better.

Current research has widely applied heteroatom doping for the promotion of catalyst activity in peroxymonosulfate (PMS) systems; however, the relationship between heteroatom doping and stimulated activation mechanism transformation is not fully understood. Herein, we introduce nitrogen and sulfur doping into a Co@rGO material for PMS activation to degrade tetracycline (TC) and systematically investigate how heteroatom doping transformed the activation mechanism of the original Co@rGO/PMS system. N was homogeneously inserted into the reduced graphene oxide (rGO) matrix of Co@rGO, inducing a significant increase in the degradation efficiency without affecting the activation mechanism transformation. Additionally, S doping converted Co

In this paper, to investigate the effect of loading method of pulse current on the tensile deformation behavior of AZ31B magnesium alloy sheet, the intermittent pulse current with short-time and high-frequency was introduced in uniaxial tensile tests and the influence of duty ratio and loading time of pulse current on the deformation behavior of AZ31B magnesium alloy sheet was discussed. The strain and temperature field distributions on the specimens were measured during the intermittent pulse electrically-assisted tension (IPEAT), and the microstructure and fracture morphology under different pulse current conditions were observed. Results shows appropriate pulse current parameters can effectively improve the elongation of AZ31B magnesium alloy sheet. The strain of the sample is closely related to temperature distribution. With the deformation of the sample, the temperature on the sample increases gradually and the temperature distribution is non-uniform along the tensile direction, resulting in an inhomogeneous strain distribution of the sample. In addition, grain growth and dynamic recrystallization were observed on the AZ31B magnesium alloy sheet in different degrees under intermittent pulse current. Fracture morphology analysis shows that the number of dimples and tearing edges increased on the fracture obtained under IPEAT. The microhardness analysis shows that when intermittent pulse current is applied in the tensile test, the hardness of the sheet may change. This research provides an effective idea for the forming process of magnesium alloy sheets, which can be used to form large size thin-walled sheet components, and can significantly improve the forming quality of the sheets.

Adsorbents, especially those with high removal efficiency, long life, and multi-purpose capabilities, are the most crucial components in an adsorption system. By taking advantage of the liquid-like mobility and crystal-like ordering of liquid crystal materials, a liquid crystal induction method is developed and applied to construct three-dimensional graphene-based adsorbents featuring excellent shape adaptability, a distinctive pore structure, and abundant surface functional groups. When the monoliths are used for water restoration, the large amount of residual oxygen-containing groups is more susceptible to electrophilic attack, thus contributing to cation adsorption (up to 705.4 mg g

Biosensors for mercury (II) (Hg2+) with high sensitivity are urgently required for food safety, ecosystem protection and disease prevention. In this study, a simple and fast detection method of Hg2+ based on the molecular beacon aptamer was established, according to the principle that Hg2+ could change the structure of the molecular beacon aptamer, resulting in the changed fluorescence intensity. All of the detection conditions were optimized. It was found that an optimal molecular beacon aptamer MB3 showed the optimal response signal in the optimized reaction environment, which was 0.08 μmol/L MB3, 50 mmol/L tris buffer (40 mmol/L NaCl, 10 mmol/L MgCl2, pH 8.1), and a 10 min reaction. Under the optimal detection conditions, the molecular beacon aptamer sensor showed a linear response to Hg2+ concentration within a range from 0.4 to 10 μmol/L and with a detection limit of 0.2254 μmol/L and a precision of 4.9%. The recovery rates of Hg2+ in water samples ranged from 95.00% to 99.25%. The method was convenient and rapid, which could realize the rapid detection of mercury ions in water samples.

The anisotropic deformation behavior and forming limit of hot-rolled Al/Mg/Al three-layered composite sheets have been investigated in detail. Uniaxial tensile tests were conducted on composite sheets at 0°, 45°, and 90° to the rolling direction. The results show that the properties of the hot-rolled 5052/AZ31/5052 three-layered composite sheet with fine grain distribution and diffusion layer of 18.71 μm were anisotropic and showed temperature dependence. The 0° direction showed the highest n value and the 90° direction the lowest. The highest Lankford parameter was found in the 45° direction, with the maximum $$ \bar{r} $$ value and minimum absolute value of $$ \Delta r $$ at 230°C. Moreover, hemispherical punch tests revealed that the composite sheet exhibited better formability at 230°C than 170°C, especially in the biaxial stress state. In the equibiaxial tensile stress state, significant anisotropy of the thickness distribution and different fracture appearance were also observed.

The development of membranes with low fuel crossover and high fuel efficiency is a key issue in direct borohydride fuel cells (DBFCs). In previous work, we produced a poly(vinyl alcohol) (PVA)-anion-exchange resin (AER) membrane with a low fuel crossover and a low fuel efficiency by introducing Co ions. In this work, a bilayer membrane was designed to improve the fuel efficiency and cell performance. The bilayer membrane was prepared by casting a PVA-AER wet gel onto the partially desiccated Co-PVA-AER gel. The bilayer membrane showed a borohydride permeability of 1.34 × 10

Asymmetric supercapacitors possess advantages of elevated capacitance, extended output voltage, and then improved power-energy characteristic. Here we report on a composite electrode prepared by electrodepositing manganese oxide into a graphene hydrogel and its capacitive performance in an asymmetric supercapacitor. The manganese oxide/graphene hydrogel exhibits a specific capacitance of 352.9 F g−1 at 1 A g−1. The aqueous asymmetric supercapacitor composed of an active carbon as a negative electrode and the manganese oxide/graphene hydrogel as a positive electrode possesses good cycle stability (91.5% of capacitance retention after 5000 cycles) and is able to deliver an energy density of 41.8 Wh kg−1 at a power density of 0.2 kW kg−1. Its possibility to serve as a power supply for a practical application was verified by lighting up a blue light-emitting diode. These results demonstrate the electrodeposition process has promising prospect in the preparation of high-performance composite electrodes for advanced electrochemical energy storage devices.

Anodic electrodepositing manganese oxide into a graphene hydrogel not only improves the carbon material's capacitive performance, but surface chemical environment of the GO framework is also affected. Apart from the deposition of nano-sized manganese oxide (about 6 nm), Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and cyclic voltammetry results confirm that reduction on oxygen-containing functional groups takes place during the anodic process. After the electrodeposition, weakness of the graphene hydrogel in capacitance is mitigated by the incorporation of the pseudo-capacitive material, with an almost 100% increase. And the composite electrode possesses superior rate capability, reversibility and cycling stability (only 8% deterioration in capacitance after 6000 charge/discharge cycles) as well.

Advanced high-strength steel has great potential for application in automotive and high-speed rail industries owing to its excellent mechanical properties. To predict the forming limit of dual-phase 500 steel sheets (DP500), Banabic’s innovative hydraulic bulging test was conducted on them, and the Gurson–Tvergaard–Needleman (GTN) ductile damage model was used to determine their failure under different strain paths. GTN damage parameters were identified using a hybrid experimental–numerical method based on the equal biaxial hydraulic bulging test. The results show that fracture of all of the DP500 specimens occurred in their polar region in experiments under different strain paths from uniaxial to equal biaxial tension. Moreover, the GTN ductile damage model could not only provide an accurate prediction of the fracture position, but also give an appropriate evaluation of the sheet forming limit under different loading paths.

The planar anisotropy (PA) and tension-compression asymmetry (TCA) of the commercially pure titanium (CP-Ti) were investigated through uniaxial tension and compression experiments at room temperature. By deep drawing experiment, the formability and the earing profile for the CP-Ti were studied at room temperature. The deep drawing simulations using the hardening rules of uniaxial tensile or compression curves were compared with experimental results. The results show that the CP-Ti has obvious PA, and the plastic strain ratiosr0,r45andr90are 1.47, 1.64 and 2.05, respectively. The CP-Ti sheet shows the tension-compression asymmetry of yielding and hardening. The TCA also shows obvious PA. The tension-compression yield strength ratio of 0°, 45° and 90° to the rolling direction are 1.12, 1.08, 1.04, and the tension-compression hardening exponent ratio are 0.86, 0.8 and 0.62, respectively. The simulative results without considering TCA indicate that the forming force, the wall thickness and earing profile are not in good agreement with the experimental ones. Therefore, the earing appeared in 45° is contribution of the PA and TCA. The TCA will reduce the thickness of the deep drawing parts, increase the earing ratio and affect the drawing force.

The preparation and capacitive behaviour of boron-doped birnessite-type manganese dioxide is described. The MnO2 has been deposited directly onto carbon fiber substrate via the in-situ redox reaction between KMnO4 and carbon fiber in the presence of sodium tetraborate. A combination of physical techniques (scan electron microscopy, transmission electron microscope, X-ray diffraction and X-ray photoelectron spectra) and electrochemical methods (cyclic voltammetry, electrochemical impedance spectra and galvanostatic charge/discharge) is used to study the effects of the presence of sodium tetraborate on the deposition process, morphology, microstructure, and capacitive properties. The repulsions among “hunter” ion [B(OH)4]– resulting from the hydrolysis of Na2B4O7 lead the nucleation points to grow outward individually and thus the formation of MnO2 films that are covered with large amounts of isolated nanoparticles about 50–100 nm in diameter. The increasing binding energies of manganese and oxygen should be a result of interstitial boron ions in MnO2 lattice. The electrochemical measurements indicate that the boron-doped MnO2 electrode has larger specific capacitance, better rate capacity as well as superior cycle stability.

The MnO 2 hierarchical hollow microspheres have been prepared by KMnO 4 partial oxidation of MnCO 3 , followed by the complete selective removal of MnCO 3 template with H 2 SO 4 . The as-prepared hollow spheres are about 1–1.5 μm in diameter with a shell about 50 nm in thickness as shown in TEM images, and are mixture of ramsdellite and akhtenskite according to the XRD analysis. The cyclic voltammetry and galvanostatic charge/discharge measurements indicate that the MnO 2 hollow microspheres possess an ideal capacitive characteristic. After experienced a charge/discharge operation for 10,000 cycles, there is only 18.5% decrease in discharge specific capacitance compared with the maximum capacitance (132.1 F g −1 at 50 mV s −1 ). The hierarchical hollow architecture may play a critical role in improving the rate capability and cycling stability of the as-prepared MnO 2 .

Electrodepositing manganese oxide into graphene hydrogel provides a facile and effective way to make full use of structural features of the hydrogel and capacity advantage of manganese oxide. The electrodeposition conditions play a key role in the deposition of manganese oxide, but little is known about their effect on electrochemical properties of the hybrid electrodes. Here, we systematically clarify the influences of deposition parameters (including current density, deposition time, Mn2+ concentration and bath temperature) on the capacitive performance (including apparent capacitance, specific capacitance, rate capability, cycling stability and charge storage mechanism) of manganese oxide/graphene oxide hydrogel hybrid electrodes. Under the proper preparation conditions, the highest specific capacitance of 453.7 F g−1 is obtained, and 92.4% capacitance retention (419.2 F g−1) is maintained after 5000 charge/discharge cycles, indicating excellent charge storage capability and cycling stability.

Synergistic effect of Ce

Binary logistic regression test for possible factors of SBI. (DOCX 16Â kb)

The boron-doped MnO 2 /carbon fiber composite electrode has been prepared via in situ redox reaction between potassium permanganate and carbon fibers in the presence of boric acid. The addition of boron as dopant results in the increase of growth-rate of MnO 2 crystal and the formation of worm-like nanostructure. Based on the analysis of binding energy, element boron incorporates into the MnO 2 lattice through interstitial mode. The doped electrode with porous framework is beneficial to pseudocapacitive reaction and surface charge storage, leading to higher specific capacitance and superior rate capability. After experienced 1000 cycles, the boron-doped MnO 2 still retain a higher specific capacitance by about 80% of its initial value. The fall in capacitance is blamed to be the combination of the formation of soluble Mn 2+ and the absence of active site on the outer surface.

With increasingly competition in the world shipbuilding market, manual and experiential technique patterns of line heating process could not meet the requirements of modern shipbuilding in product speed and quality. In recent years, the improvement of productivity for line-heating process is one of the goals in the shipbuilding industry, which means an accurate prediction model is very important. In this study, a finite element analysis (FEA) model for the line-heating process was established and experiments were conducted to prove the validity of the model. The final numerical results are in good agreement with experiment results. Based on the FEA model, the feasibility of the multiple-torch process is verified. The multiple-torch process could greatly save processing time, which is entirely feasible in the specific automation implementation. Finally, the effect of heat line spacing is analyzed, which could provide important information for the line-heating process design. The proposed method presents a valuable reference for the study of the similar thermal process.

Self-standing MnO 2 electrodes have been fabricated through the redox reaction between carbon fiber and potassium permanganate. The porous film of birnessite-type MnO 2 deposited tightly onto surfaces of the carbon fibers to form manganese dioxide/carbon fiber cloth electrode. The electrodes have not only excellent capacitive performances, but also superior electrochemical stability. Owing to the formation of thin-film morphology, porous structure and the intimate contact between the electroactive material and the current collector, the MnO 2 film provides an enhancement of the kinetics by short transport/diffusion path lengths, timely accompanying of electrolyte and large specific surface areas, thus both high energy density and high power density are achieved. In addition to the effective release of stress resulting from charge/discharge, the porous structure also facilitates accompanying electrolyte at high rate operation and avoiding dramatic capacitance fade in cycling. The specific capacitance still retains at least about 84% after continuous 5000 charge/discharge cycles.

Electrodepositing manganese oxide in a three-dimensional graphene architecture has barely been explored, and therefore an exploratory but systematic investigation was conducted. A series of manganese oxide/graphene hydrogel electrodes were prepared by galvanostatic technique. The effects of electrodeposition condition, including current density, deposition time, Mn2+concentration and bath temperature, on the morphology and capacitive performance of the deposits were investigated. Nucleation and growth processes of the deposited manganese oxide were then deduced. An optimal capacitance of 452.5 F g−1 was got. This study could provide insight into the crystallization mechanism for electrochemical preparation of MnOx/graphene electrode for advanced energy storage/conversion devices.

The lifting padeyes are widely used in the offshore and shipbuilding industry. The design of lifting padeye requires extremely high safe reliability and economic rationality. Based on finite element analysis (FEA), the variations of stress and deformation with external force and hoist angle are analyzed. For minimizing cost of steel, optimum design models of lifting padeye were built and the reliability of the optimum design scheme was proved. The results show that the optimum design accords with structure design principle and the cost of padeye steel reduce notably.

Spherical and octahedral Cu2O nanocrystals were prepared by reducing copper acetate monohydrate (Cu (CH3COO)2·H2O) with hydrazine hydrate (N2H4·H2O) at ambient temperature and pressure. The influence of solution composition on the morphology and microstructure of Cu2O nanocrystals were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Ultraviolet and visible light spectrometer (UVvis) was employed to investigate the photocatalysis behavior of the Cu2O samples. The results show that Cu (OH)2 was initially formed with the addition of NaOH and then reduced into Cu2O by N2H4·H2O. At the same time, a portion of Cu2O particles were further reduced to Cu, but the increasing of O2 contents in the solution under vigorous stirring reconvert Cu into Cu2O whichlead to the formation of pure Cu2O nanocrystals. The alkaline condition which provided by NaOH was the prerequisite for obtaining spherical and octahedral Cu2O crystals. The facile method was provided to fabricate Cu2O nanocrystals with outstanding photocatalysis performance at low temperature, which may play an important role in sewage treatment and organic pollutants decomposition.

The effect of forming temperature on the deep drawability (limit drawing ratio (LDR)) of AZ31 magnesium alloy sheet was studied both numerically and experimentally by the use of finite element analysis software DYNAFORM and specially designed warm deep drawing die set. The simulation model was built by SolidWorks 2009, 3-Parameter_Barlat model with BT shell unit was adopted as material model. The constitutive relation of the material was provided by uniaxial isothermal tension tests at different temperatures. After being set, all parameters were referred to famous explicit dynamic solver LS-DYNA. The simulation results showed that the LDR of the AZ31 magnesium alloy sheet is increased with the increase of the temperature initially, but after the temperature reached 423K, the LDR reached the maximum, and then decrease with the increase of temperature in the temperature range studied (room temperature-673K). PTEF was used as lubricant in the experiment. Experimental results showed same trend as numerical simulation results in the studied range of temperature, and LDR reached the maximum of 3.0 at 423K. It is shown that the results of numerical simulation have a good agreement with that of the experiment. By analyzing the microstructure of the drawn-cup walls at different temperatures, it is found that grains were stretched along the direction of tension at temperatures lower than 423K. And there appeared a large number of fine recrystallized grains when forming temperature is 423K showing that dynamic recrystallization occurred during forming process. Dynamic recrystallization conducted completely when forming temperature increased higher than 423K, but the material softening would aggravate with the increase of temperature and on the contrary would do harm to the deep drawing of AZ31 magnesium alloy sheet, resulting the decrease of LDR.

A free-standing, totally flexible and light-weight manganese dioxide/carbon fiber cloth electrode has been simply and cost-effectively fabricated by direct reduction of permanganate. The nano-scaled MnO 2 film, being in physical contact with the carbon fiber substrate, provides an enhancement of the kinetics and mechanical flexibility. The electrochemical stability is improved due to the efficient release of bending stress by inter-cluster gap adjustment of nano-scaled MnO 2 film and adsorption of carbon fibers. The maximum capacitance loss is only of 0.05% during operating shape change. By short transport/diffusion path lengths and large specific surface areas, the nano-scaled MnO 2 film presents superior rate capability. The specific capacitance still retains about 53% when the scan rate increases as much as 50 times.

The addition of boron as a dopant during the reaction between carbon fiber and permanganate led to significant enhancement of the growth-rate and formation of the porous framework. The doped MnO2 was superior to the pristine sample as electrode materials for supercapacitors in terms of the specific capacitance and rate capability.

TiO2 anatase thin films on quartz substrates were prepared with sol-gel method. The dry gel films, made by spin coating 10 times, were calcined at various temperatures. From X-ray diffraction analyses, it is found that the anatase to rutile phase transformation temperature of the films is higher than 850°C, the films are preferentially oriented on (0 0 1) plane, i. e.c-axis oriented. The thickness, refractive indexes, absorption coefficients and extinction coefficients of the films were determined from UV-Vis transmission spectra of the films using a UV-Vis spectrophotometer. The thickness of the films is about 570 nm. The refractive indexes, absorption coefficients and the extinction coefficients of the present films are larger than the values of anatase films prepared by sputtering. This indicates that the films made with sol-gel method are very dense.

We demonstrate an application of fiber Bragg grating to measure the index of refraction of an unknown liquid by using a cladding depleted FBG. The measurements of the index of refraction were calibrated by the index oil with known index of refraction. Samples of liquid with difference percentage of sugar content were prepared and measured the index of refraction using this method. It shows that accuracy of index of refraction measurement as high as 0.01 can be achieved.

Kesternich et al. and Jung et al. have recently raised serious questions as to whether past investigations of permanent radiation induced electrical degradation (RIED) of ceramics were actually monitoring bulk effects, as claimed. Their evidence to the contrary appears compelling. The present investigation provides evidence that bulk damage does exist and is in the form of dislocations. Discussions are focussed on some aspects of the controversy between evidence for RIED, as reported in the past, and evidence for radiation enhanced surface contaminations.

A modified optimization-based contour detection method was presented to compute the lumen area of the coronary artery from intravascular ultrasound (IVUS) video images. First, the search range for the artery inner wall was determined based on the continuity of IVUS video frames. Next, the internal and external energy were calculated to describe the smoothness of the arterial wall and the grayscale variation of ultrasound images, respectively. Here, a novel form of the external energy which combines the gradient and variance of the intensity of image in the radial direction was used. Finally, the minimal energy path based on the optimum contour of the artery wall was obtained using circular dynamic programming (DP). By the comparison with the typical DP procedure using the traditional external energy form, based only on the image gradient, the reliability of this modified method is considerably improved in the measurement of coronary artery lumen area.

The article studies inventory demand forecast in regional logistics network of retailers, distribution center, and suppliers. It considers the demand difference between distribution center, suppliers and retailers from the perspective of supply chain, and according to different level of demand, determines the relationship between the shortest circuit matrix and demand mapping in regional logistics network, based on which a multi-echelon demand forecasting model is built and the accurate inventory demand of every level is obtained. At last, we prove the correctness and feasibility of the model through a case.

Characteristics of tactical guarantee network are analyzed, based on which a network model with uniformly random degree distribution and cascade failure survivability model is proposed. Supposing network nodes' initial capacity and load were equal, the critical point of network cascade collapse is derived by probability function method analysis. The research shows that: as network load increases, there will be a critical load value. When network load exceeds the critical value, a random node failure in the network will cause the entire function network to collapse. Finally, computer simulation is applied to verify the correctness of the analytic deduction.

Through applying performance based yardstick competition, regulator can obtain signals that have correlation with the transmission and distribution Enterprises' cost style. Using these signals, regulator is able to improve the scheme of incentive regulation. In order to analyze the effect of the improved regulation scheme on incentive level, a model is built. We consider the regulation problem with complete contracting in a principal-agent model with adverse selection and review within this model the channel by which external competition parameters affect incentives within the regulated enterprise. The conclusion of the model shows that effect of improved scheme isn't always positive. If the correlation between signal and cost style is strong enough, the new scheme of regulation can increase the lever of incentive to enterprises; if not, may decrease. An intuitionistic example confirms this conclusion. So, when regulator wants to use signals to reform the scheme of regulation, she must ensure the strong correlation between signal and cost style rather than cause negative incentive.

To assess the microvascular function of coronary artery after intracoronary microembolization using coronary resistance system.The left anterior descending coronary artery (LAD) of 10 pigs weighing 21 kg-25 kg were embolized by repetitive injection of microspheres 45 micro m in diameter through a 2.8F Tracker catheter. Intra-vascular ultrasound (IVUS) images, intracoronary Doppler and pressure signals in the middle segment of LAD were acquired by use of intracoronary ultrasound imaging catheter, Doppler flow wire and pressure wire separately. Intracoronary bolus injection of 18 micro g adenosine was administered to maximally vasodilate the coronary arterial bed through the 2.8F Tracker catheter. The resting and hyperemic signals were acquired respectively before microembolization and in different levels of microembolization. Coronary resistance system reflecting the resistance to pulsatile coronary flow was established by a self-made software of PC system. The resting and hyperemic CR parameters included average resting coronary resistance (rCR) and average minimal coronary resistance (min-CR), the first-harmonic rCR and min-CR, the first-harmonic rCR orientation and min-CR orientation, and so on. Factor analysis was performed to extract the best coronary parameter from the coronary resistance parameters.Factor analysis showed that the first-harmonic rCR and first-harmonic min-CR were correlated better with the first component extracted from the resting and hyperemic CR parameters than rCR and min-CR, with the correlation coefficient being 0.913 and 0.950 in the first-harmonic CR and first-harmonic min-CR respectively. No significant difference in min-CR was found between the value at the dosage of 5 x 10(4) microspheres and that before microembolization. The min-CR value increased markedly from 271 mm Hg.ml(-1).s(-1) +/- 99 mm Hg.ml(-1).s(-1) at the dosage of injecting 5 x 10(4) microspheres to 361 mm Hg.ml(-1).s(-1) +/- 158 mm Hg.ml(-1).s(-1) at the dosage of injecting 10 x 10(4) microspheres (P0.05). The min-CR value remained almost unchanged from the dosage of 10 x 10(4) to 15 x 10(4) microspheres. There was no significant difference concerning the first-harmonic min-CR between the value at the dosage of 5 x 10(4) microspheres and that before microembolization. Along with the increase of number of microspheres injected the min-CR value increased gradually. The min-CR value was increased significantly than that before microembolization since the number of microspheres injected surpassed 14 x 10(4).The first-harmonic min-CR reflected the coronary microvascular dysfunction in different extents of microembolization better than min-CR. The extent of coronary microvascular dysfunction wasn't linearly related to the extent of microembolization.

By means of monitoring with the reflection high energy electron diffraction (RHEED) -and its intensity oscillations, the GaSb/AlSb/GaAs strained layer heterostructures have been suc-cessfully grown on semi-insulating (100) GaAs substrates by molecular beam epitaxy (MBE) The RHEED patterns show that the GaSb surface grown under Sb-stabilized condition has C (2×6) structure and the AlSb surface has (1×3) Sb structure. We observed and recorded the RHEED intensity oscillations during the growth of GaSb and AlSb. Using the information provided by the RHEED intensity oscillations, we successfully prepared a GaSb/AlSb super-lattice with 10 periods. The transmission electron micrograph shows the interfaces in the su-perlattice are sharp and planar. If the AlSb buffer layer is thick enough under a proper growth condition, a high-quality GaSb epitaxy will be grown on SI GaAs substrate. The full width at half maximun (FWHM) of the peak corresponding to the GaSb epilayer in double-crystal X-ray diffraction rocking curve is less than 300 seconds. Undoped GaSb is p-type with carrier concentration of 2.12×1016 cm-3 and mobility of 664cm2/V·s at room temperature.

Moon and Pao [1] first dealed with magnetoelastic buckling of a plate, with a great discrepancy between their theoretical predictions and experimental results. Later some investigators showed that this discrepancy is due to the difference between the analytical and experimental models. By means of the analysis of buckling field, we find that the mentioned discrepancy above can be greatly decreased by considering the influence of specimen with finite size. In the present paper, the BEM and Weighted Residual Methods are used to calculate the buckling fields Bc of finite size plate. As an example, the buckling fields Bc of cantilever beam-plate in uniform field is obtained and shown in table 1.