浅谈汽车机械制图课程教法创新与实践

汽车机械制图作为汽修专业的一门基础课程,应针对职业院校汽修专业学生特点,依照汽修专业人才培养方案,在不断融入信息化技术的同时,优化教学结构、强调实用能力、创新考核模式,继而不断激发学生的学习兴趣,提高学生的综合素质,使学生快速熟悉本专业特点,以满足企业用工需求。

Formation mechanism and organizational controlling of ultra-fine-grain copper processed by asymmetrical accumulative rolling-bond and annealing

The initial copper with large grain sizes of 60-100 μm was processed by six passes asymmetrical accumulative rolling-bond （AARB） and annealing, the ultra-fine-grained （UFG） copper with grain size of 200 nm was obtained, and the microstructures and properties were studied. The results show that there are large sub-structures and also texture component C for the UFG copper obtained by six passes AARB, possessing high strength and microhardness in company with poor elongation and conductivity. Thereafter, the UFG copper was annealed at 220 °C for 35 min, in which the sub-structures disappear, the grain boundaries are composed of big angle grain boundaries, and the textures are composed of a variety of texture components and parts of twins. Compared with the UFG copper obtained by six passes AARB, the tensile strength and yield strength for the UFG copper obtained by six passes AARB and annealing at 220 °C for 35 min are decreased slightly, the elongation and conductivity are improved obviously.

Microstructure evolution of Al-Ti liquid-solid interface

Al-Ti diffusion couples were made by embedded technology and treated at the temperature between the melting points of Al and Ti. The microstructure evolution and growth mechanism of the Al-Ti DRZ were investigated. The result shows that the DRZ, the mixture of TiAl3 and Al, grows layer by layer along their chemical equilibrium zone. In the course, the growth interface moves toward the aluminum side. TiAl3 is the only new phase which forms earliest in the course of heat-treatment. The growth mechanism of the DRZ changes after the phase transition of titanium. Before the phase transition of titanium, the growth of the DRZ is controlled by the dissolution speed of the titanium to the molten aluminum, while after the phase transition of titanium, the growth is controlled by the chemical reaction speed of Al and Ti atoms, and consequently, its growth rate is greatly increased.

Quantum Dot Lasers Fabricated by Self-organized Growth

Quantum dot lasers have excellent characteristics such as temperature stability of threshold current and ultra-high material gain. Quantum dot structures fabricated by self-organized growth have high crystalline perfection, high quantum yield of radiative recombination and high size homogeneity. Main advantages and operating properties of quantum dot lasers fabricated by self-organized growth are briefly introduced.

Neuroendocrine gastric carcinoma expressing somatostatin: A highly malignant, rare tumor

Poorly differentiated gastric neuroendocrine carcinomas, although rare, deserve particular attention, as they are aggressive and have an extremely poor prognosis. In this report we describe a gastric neuroendocrine carcinoma with rapidly fatal outcome. Immunohistological staining of the resected specimens revealed that the tumor was an endocrine carcinoma. The tumor disclosed intense immunoreactivity to pan-neuroendocrine markers and diffuse somatostatin immunoreactivity. There were no psammoma bodies and no demonstrable association with yon Recklinghausen＇s neurofibromatosis. In the gastrointestinal tract, neuroendocrine tumors producing predominantly somatostatin have been described only in the duodenum. To the best of our knowledge, the present report is the second case report of a neuroendocrine gastric carcinoma expressing diffusely somatostatin as the only neuroendocrine regulatory peptide.

Controlling the Collision Between Two Solitons in a Two-Component Condensate by Interspecies Interactions

We present a family of the solutions of two-component Bose-Einstein condensates with time-dependentscattering length by means of multiple-scale method.Our numerical calculations show that the collision properties (theposition,the time,and the frequency of the collision) between two solitons can be controlled by the time-dependentinterspecies scattering length.Meanwhile,we also find that the amplitude of the solitons is close related to the timedependentinterspecies scattering length.

BIOEQUIVALENCE BETWEEN rhGH FOR RECONSTITUTION AND READY-TO-USE rhGH IN TWO LIQUID FORMULATIONS

Objective To evaluate the bioequivalence between recombinant human growth hormone （rhGH） for reconstitution, and two dosages of liquid formulation of rhGH [ （151U） 5mg or （301U） lOmg per 3ml ]. Methods The study drugs were tested in a randomized, single-blind and three-period crossover studies in 24 healthy male subjects. The three drugs were administered by subcutaneous injection at a dose of O. 21U/kg body weight. A continuous somatostatin infusion was given in order to suppress the secretion of endogenous GH. The ve- nous blood samples were drawn at different time points to test the serum concentration of GH. The pharmacokinetic parameters were analyzed by statistical methods. Results 90% confidence intervals （CI） of AUC0-24h among three products were all within 80% - 125% interval （ 103. 4% - 116. 5%, 105. 7% - 119. 6% and 91.9% - 103. 7%, respectively）, and the Cls of C,~ among three products were all within 70% - 143% interval （91.9% - 114. 0%, 103. 7% -127. 2% and 81.6% -97. 4%, respectively）. There was no statisitical difference of tmax among all the three products. Conclusion These data demonstrate that there is bioequivalence between rhGH for reconstitution and two liquid formulations of rhGH.

Antimicrobial Activities of Some Plants from Ivorian Flora on Southern Blight in Cote d＇ivoire

This study aims at determining and comparing the in vitro antifungal activity of six EOs （essential oils） extracted from Monodora myristica, Melaleuca quinquenervia, Eucalyptus torelliana, Chenopodium ambrosioides, fresh Zingiber officinalis and dehydrated Zingiber officinalis with those of three synthetic fungicides （Callicuivre, Banko plus and Mancozeb） on Sclerotium rolfsii a pathogenic fungus of tomato in Cote d＇Ivoire. The products were added to PDA （potato dextrose agar） medium at various concentrations. The results showed different aspects of the mycelium, different activities on mycelium growth and sclerotia production depending on the explants （mycelium or sclerotia）. Depending on their IC and MGI （mycelium growth inhibition）, the oils stemming from Chenopodium ambrosioides and fresh Zingiber officinalis showed more inhibitory activities on mycelial growth （reduction rate of 100%） and sclerotia production at 250 ppm. These activities were close to or even greater than those of fungicides. The mancozeb fungicide showed stronger activity than the others by inhibiting mycelium growth and sclerotia production of mycelium explants at 250 ppm. This study offers the possibility of using EOs in the control strategies of Sclerotium rolfsii.

Inhibitory effect of celecoxib combined with cisplatin on growth of human tongue squamous carcinoma Tca8113 cell xenograft tumor

Objective:The aim of this study was to observe the inhibitory effect of application of COX-2 inhibitor,celecoxib,combined with cisplatin on the growth of human tongue squamous carcinoma Tca8113 cell xenograft by animal experiment.Methods:The nude mice were transplanted subcutaneously with Tca 8113 cells,and then were administrated with celecoxib,cisplatin or celecoxib combined with cisplatin respectively,and were sacrificed after 35 days.The weight of xenograft was measured to calculate the tumor inhibition rate.The histological change was studied under light and electron microscope.The COX-2 protein expression was observed by immunohistological staining.And the COX-2 mRNA expression was determined by RT-PCR.Results:Celecoxib,the COX-2 inhibitor,could not only inhibit the growth of Tca8113 cell xenograft tumor and COX-2 protein expression,but also enhance the inhibitory effect cisplatin on xenograft tumor growth significantly.The tumor inhibition rates of celecoxib group,cisplatin group and celecoxib plus cisplatin group were 15.63%,37.50% and 82.81% respectively that was statistically significant compared to control group(P < 0.01).The combined application of celecoxib and cisplatin could inhibit tumor growth more significantly than that of separated application(P < 0.01).The inhibitory effect of celecoxib on COX-2 mRNA expression of Tca 8113 cell was weaker and not significant(P = 0.073).Conclusion:Celecoxib can not only inhibit xenograft tumor growth in nude mice,but also enhance the inhibitory effect of CDDP on Tca 8113 transplanted tumor growth in nude mice.The mechanism maybe related to inhibition of COX-2 protein expression,which offers beneficial reference to further explore the mechanism between inhibition of COX-2 enzyme activity and prevention of head and neck tumor.

From cluster assembly to ultrathin nanocrystals and complex nanostructures

Ultrathin nanostructures have attracted much attention in recent years due to their predictable novel properties and various potential applications. The improvement in synthetic skills has led to many successful syntheses of nanostructures including zerodimensional (0D) nanoclusters, one-dimensional (1D) nanowires, two-dimensional (2D) nanosheets and other higher-level complex nanostructures, where cluster-assembly of primary nanocrystals is a common process. In this review, progress in ultrathin nanocrystals in the last decade and several important factors in the growth mechanisms are covered. By giving examples of cluster assembly from 1D to 3D nanostructures, the utility of cluster assembly in the synthesis of new materials has been demonstrated.

Metallurgical microstructure control in metal-silicon reactions

A comprehensive review on interfacial reactions to form silicides between metal and Si nanowire or wafer is given.Formation of silicide contacts on Si wafers or Si nanowires is a building block needed in making current-based Si devices.Thus,the microstructure control of silicide formation on the basis of kinetics of nucleation and growth has relevant applications in microelectronic technology.Repeating events of homogeneous nucleation of epitaxial silicides of Ni and Co on Si in atomic layer reaction is presented.The chemical effort on intrinsic diffusivities in diffusion-controlled layer-typed intermetallic compound growth of Ni2Si is analyzed.

Microstructural evolution and mechanism of grain growth in magnesia ceramics prepared by high pressure and temperature with ultra-high heating rate

The fast densification method of combustion reaction plus quick pressing was adopted to prepare nanocrystalline ceramics.The densification process of magnesia compact with a particle size of 100 nm was investigated,under the applied pressure of up to 170 MPa,and the temperature range of 1740–2080 K with ultra-high heating rate(above 1700 K/min).High-purity magnesia ceramics with a relative density of 98.8%and an average grain size of 120 nm was obtained at 1740 K,and the grain growth during the densification process was effectively restrained.The characteristic morphology of evaporation-condensation was observed in the compact prepared at 2080 K,which revealed the actual process of mass transfer by gas diffusion.Moreover,the investigation on the microstructure evolution and mechanism of grain growth was carried out,on the basis of as-preserved nanocrystalline ceramics.The result indicated that the grain growth of the nanocrystalline MgO was controlled by the mechanism of evaporation-condensation rather than surface diffusion.Furthermore,the pressure had an influence of restraining the grain growth based on solid diffusion and strengthening the effect of gas diffusion with the increasing temperature.Under the particular conditions,there existed an appropriate temperature for the densification of nanocrystalline magnesia,while the excessive temperature would exaggerate grain growth and impede densification.