粘介质成形工艺特点与应用分析

简要介绍了近来出现的利用粘性介质传压进行冲压成形的一种新工艺。通过粘介质成形（ＶＰＦ） 实验与以水为介质的液压成形（ＨＦ） 模拟的对比分析， 得出了ＶＰＦ过程中的一些工艺特点，并分析了ＶＰＦ工艺在飞行器制造中的应用前景。

用于粘性介质压力成形的介质性能的研究

粘性压力成形(VPF)采用一种半固态、可流动并具有高粘度的材料作为成形传力介质,粘性介质的性能对板材变形有很大影响,本文根据粘介质压力成形的要求,选择了3种不同分子量的粘介质材料,并讨论了它们的基本性能。采用剪切流变方法对3种粘性介质的流变性能进行了分析,获得了3种介质的转速-扭矩关系曲线,从而得出粘性介质应力应变随时间的变化规律。自行设计并制造了粘性介质的挤压实验装置,通过3种不同分子量的粘性介质的挤压实验,分析了挤压力随挤压速度及挤压比的变化规律。实验结果表明,随着挤压速度和挤压比的增大粘性介质挤压力增大,粘性介质有较强的速率敏感性。

犁骨舌形粘骨膜瓣加腭骨复合组织瓣修复双侧腭裂的研究

目的 探讨重建腭裂患者的正常形态和解剖结构以恢复正常功能活动的手术方法。方法 采用犁骨舌形粘骨膜瓣加腭骨复合组织瓣术修复双侧腭裂。结果 用此法治疗双侧腭裂 18例 ,腭部解剖功能恢复成功率达 10 0 % ,语言功能效果评价优良率达 83 3 %。结论 犁骨舌形粘骨膜瓣加腭骨复合组织瓣修复双侧腭裂临床效果较满意。

二瓣后推术并舌形粘骨膜瓣修复不完全腭裂体会

目的 评价二瓣后推术并舌形粘骨膜瓣修复不完全腭裂的方法。方法 应用二瓣后推术并舌形粘骨膜瓣修复 5 7例不完全腭裂。结果 5 7例不完全腭裂病例术后无一发生穿孔。结论 二瓣后推术并舌形粘骨膜瓣修复不完全腭裂 ,对防止裂隙前份术后穿孔效果良好。

细胞表面糖蛋白表达异常与涎腺多形性腺瘤复发的关系

目的研究多形上皮粘蛋白1(mucin1)和E_钙粘蛋白(E_cd)与涎腺多形性腺瘤复发的关系,探讨可预测涎腺多形性腺瘤复发的指标。方法以52例涎腺多形性腺瘤石蜡标本为研究对象,其中初发33例,复发12例,恶性7例。采用显微镜观察肿瘤周围包膜的状况,免疫组织化学检测初发、复发、恶性多形性腺瘤细胞的mucin1和E_cd蛋白表达情况。结果初发和复发多形性腺瘤的包膜状况差异无显著性(P>0.05)。初发多形性腺瘤细胞的mucin1蛋白表达阳性率(64%)与复发者(67%)的差异无显著性(P>0.05)。两者的差别表现为mucin1阳性表达部位分布不同,初发者主要为细胞顶膜染色(19/21),复发者主要为整个细胞膜染色(6/8),两者差异有显著性(P<0.05);恶性多形性腺瘤染色部位与复发者相同,且阳性表达率显著升高。3种肿瘤的E_cd表达阳性率差异无显著性(P>0.05)。结论多形性腺瘤的包膜状况在预测其复发潜能上实际应用性不强,多形性腺瘤细胞E_cd的表达改变与其复发潜能无显著关系。Mucin1在多形性腺瘤细胞膜上的异常分布,使其倾向于向周围分散生长,这种异常分布可作为预测多形性腺瘤复发的指标之一。

食物嵌塞圈成形触点粘接技术的临床治疗方法及疗效观察

目的探讨圈成形触点粘接技术治疗食物嵌塞,并观察临床疗效。方法对符合纳入标准的单一垂直型食物嵌塞患者进行圈成形触点粘接治疗,同时随访治疗后1周、1月、3月的临床疗效。结果 47例食物嵌塞患者经圈成形触点粘接技术治疗后1周、1月、3月随访,治愈率分别为100%,98.1%,98.1%。结论圈成形触点粘接技术是一种能有效减轻或治愈单一垂直型食物嵌塞的治疗方法,能最大程度的保护牙体牙周组织。短期疗效明显,长期效果还有待于进一步观察。

Determination of interfacial adhesive properties for polymeric film by blister test

The interfacial adhesive properties ofpolypropylene/stainless steel were studied by the blister test. The polypropylene film with a squared free-standing window was pressured by oil from one side of film. The corresponding deformation field was observed by a digital speckle correlation method. The experimental results show that the squared film deforms and debonds from stainless steel with the increase of pressure. The debonding of the squared film in initiates from the center of edge and extends to the comer, and then the deformation of film evolves from square to circle shape. The interfacial adhesive energy of polypropylene/stainless steel is （22.60±1.55） J/m2, which is in agreement with that measured by film with a circular window.

Mathematical Model Analysis of Quasi Preconsolidation Soft Clay

Soft clay may cause quasi preconsolidation effect under the constant hydrostatic pressure after some time. The result of drained triaxial test represents the effective stress yield surface, which can be described by simple binary linear fabric model. Therefore the pore pressure and deformation of clay can be decided. It also can be used to resolve the real boundary problems with finite element method.

Viscoplastic friction and microstructural evolution behavior of laser-clad Co-Cr-Ni-Mo coating

The viscoplastic friction and nanostructure formation mechanism of laser-clad Co-based coating were studied by rotary friction between laser-clad Co-Cr-Ni-Mo coating and WC-Co rod.The friction coefficient,friction interface temperature and axial displacement—time curves during rotary friction process were measured.The results showed that all the curves firstly experienced rising stage and then steady stage.The rising stage corresponded to sliding friction while the steady stage corresponded to viscoplastic friction.After viscoplastic friction processing,three typical zones of viscoplastic deformation zone,thermo-mechanically affected zone,and original laser-clad zone can be observed successively from the friction surface to the interior.The viscoplastic deformation significantly crushed the network M23C7 phase in original laser-clad zone and made it dispersively distributed with equiaxial shape and in nano-scale.The viscoplastic zone,in width of 37-131 μm,is mainly characterized by refined M23C7 and α-Co phase with grain size bellow 50 nm,and even a small quantity of amorphous.Thus,the hardness of viscoplastic zone about HV997 was improved compared with the hardness of original laser-clad zone about HV600.

Rapid Manufacturing of Metal Parts

As a key technology of rapid prototyping and manufacturing (RP&M), rapid manufacturing of metal parts is a target of RP&M. Introducing selective laser sintering (SLS), an important branch of RP&M, this paper gives a new method oriented on low power SLS system to fabricate metal parts. With this kind of technology, the mixture of metal and polymer powder is sintered first to get green part, then, after debinding and metal infiltration, dense parts are gotten. In the end, influencing factors of this technology are analyzed. At the same time, some applications are given.

Mitral pseudostenosis due to a large left atrial myxoma

Myxomas are benign cardiac tumours that are mostly （75%） located in the left atrium, but they also can be found in the right atrium （15%-20%）, in the right ventricle （4%） and in the left ventricle （3%）.

Numerical Simulation of Viscous Flow Through Spherical Particle Assemblage with the Modified Cell Model

The cell model developed since 1950s is a useful tool forexploring the behavior of particle assemblages, but it demandsfurther careful development of the outer boundary conditions so thatinteraction in a particle swarm is better represented. In this paper,the cell model and its development were reviewed, and themodifications of outer cell boundary conditions were suggested. Atthe cell outer boundary, the restriction of uniform liquid flow wasremoved in our simulation conducted in the reference frame fixed withthe particle.

Combined goblet cell carcinoid and mucinous cystadenoma of the vermiform appendix

Goblet cell carcinoid is an uncommon primary tumor of the vermiform appendix, characterized by dual endocrine and glandular differentiation. Whether goblet cell carcinoid represents a morphological variant of appendiceal classical carcinoid or a mucin-producing adenocarcinoma is a matter of conjecture. Rare cases of goblet cell carcinoid with other concomitant appendiceal epithelial neoplasms have been documented. In this report, we describe a rare case of combined appendiceal goblet cell carcinoid and mucinous cystadenoma, and discuss the possible histopathogenesis of this combination.

Estimation of the van Genuchten Soil Water Retention Properties from Soil Textural Data

The van Genuchten (vG) function is often used to describe the soil water retention curve (SWRC) of unsaturated soils and fractured rock. The objective of this study was to develop a method to determine the vG model parameter m from the fractal dimension. We compared two approaches previously proposed by van Genuchten and Lenhard et al. for estimating m from the pore size distribution index of the Brooks and Corey (BC) model. In both approaches we used a relationship between the pore size distribution index of the BC model and the fractal dimension of the SWRC. A dataset containing 75 samples from the UNSODA unsaturated soil hydraulic database was used to evaluate the two approaches. The statistical parameters showed that the approach by Lenhard et al. provided better estimates of the parameter m. Another dataset containing 72 samples from the literature was used to validate Lenhard's approach in which the SWRC fractal dimension was estimated from the clay content. The estimated SWRC of the second dataset was compared with those obtained with the Rosetta model using sand, silt, and clay contents. Root mean square error values of the proposed fractal approach and Rosetta were 0.081 and 0.136, respectively, indicating that the proposed fractal approach performed better than the Rosetta model.

Time-dependent response of laminated isotropic strips with viscoelastic interfaces

The two dimensional problem of simply supported laminated isotropic strips with viscoelastic interfaces and under static loading was studied. Exact solution was derived based on the exact elasticity equation and the Kelvin-Voigt viscoelastic interfacial model. Numerical computations were performed for a strip consisting of three layers of equal thickness. Results indicated that the response of the laminate was very sensitive to the presence of viscoelastic interfaces.

Main Clay Minerals in Soils of Fujian Province, China

The clay minerals of more than 200 soil samples collected from various sites of Fujian Province were studied by the X-ray diffraction method and transmission electron microscopy to study their distribution and evolution. Montmorillonite was found in coastal solonchak, paddy soils derived from marine deposit, lacustrine deposit and river deposit, and some latentic red soil, red soil and yellow soil with a low weathering degree. Chlorite existed mainly in coastal solonchak and paddy soil developed from marine deposit. 1.4 nm intergradient mineral appeared frequently in yellow soil, red soil and latentic red soil. The content of l.4 nm intergradient mineral increased with the decrease of weathering degree from latentic red soil to red soil to yellow soil. Hydrous micas were more in coastal solonchak, paddy soils derived from marine deposit, lacustrine deposit and river deposit, and purple soil from purple shale than in other soils. Kaolinite was the most important clay mineral in the soils in this province. The higher the soil weathering degree, the more the kaolinite existed. From yellow soil to red soil to latentic red soil, kaolinite increased gradually. Kaolinite was the predominant clay mineral accompanied by few other minerals in typical latentic red soil. Tubular halloysite was a widespread clay mineral in soils of Fujian Province with varying quantities. The soil derived from the parent rocks rich in feldspar contained more tubular halloysite. Spheroidal halloysite was found in a red soil and a paddy soil developed from olivine basalt. Gibbsite in the soils in this district was largely 'primary gibbsite' which formed in the early weathering stage. Gibbsite decreased with the increase of weathering degree from yellow soil to red soil to latentic red soil. Goethite also decreased in the same sequence while hematite increased.

Improvement of anticorrosion and adhesion to magnesium alloy by phosphate coating formed at room temperature

A new surface protection process was developed to magnesium alloy against corrosion in aggressive environments.Firstly,a phosphate coating was formed on rinsed magnesium alloy.Then,powder painting was carried out on the phosphated magnesium alloy.Surface morphologies and phase compositions of the phosphate coating were investigated by X-ray diffraction(XRD) and scanning electron microscope(SEM) .The results show that the phosphate coatings formed in bath containing earth additives at room temperature have dense and fine microstructure.The phosphate coating provides excellent paint adhesion to the magnesium alloy. Salt spray tests indicate that the corrosion resistance of the phosphate coating plus paint could meet the demand of magnesium alloy automobile components in aggressive environments.

Gastric ghrelin in relation to gender,stomach topography and Helicobacter pylori in dyspeptic patients

AIM： To investigate the level of gastric ghrelin in stomach mucosa of dyspeptic patients in relation to Helicobacter pylor/（H pylori） infection, bacterial cytotoxicity, topography and gender.METHODS： The study comprised 40 premenopausal women （19 H pylori positive） and 48 men （17 H pylori positive） with functional dyspepsia. All gastric biopsy specimens revealed normal mucosa or non-atrophic gastritis. Gastric ghrelin concentration was determined by Enzyme linked immunosorbent assay. The cagA and vacA strains of bacterial DNA were identified by multiplex polymerase chain reaction.RESULTS： In general, infection with H pylori caused an increase in gastric ghrelin level regardless of gender and stomach topography. Significantly more hormone was present in both, non-infected and H pylori positive female samples, as compared to males. The distribution of bacterial strains showed cagA（＋） vacA slml and cagA（-） vacA s2m2 genotypes as the most common infections in the studied population. A tendency to higher ghrelin levels was observed in less cytotoxic （cagA negative） strain-containing specimens from the antrum and corpus of both gender groups （without statistical significance）. CONCLUSION： An increase in gastric ghrelin levels at the stage of non-atrophic gastritis in H pylori positive patients, especially in those infected with cagA（-） strains, can exert a gastroprotective effect.

Ni^(2+) treatment causes cement gland formation in ectoderm explants of Xenopus laevis embryo

We found T-type calcium channel blocker Ni2+ can efficiently induce the formation of cement gland in Xenopus laevis animal cap explants. Another T-type specific calcium channel blocker Amiloride can also induce the formation of cement gland, while L-type specific calcium channel blocker Nifedipine has no inductive effect. These results may offer us an new approach to study the differentiation of cement gland through the change of intracelluax calcium concentration.