Mg-Mg_2Si-MgO复合材料的反应自组织合成机理

以纯Mg粉,SiO2粉为原料,采用反应自组织生长的方法制备了以MgO,Mg2Si为增强相的镁基复合材料。通过对试样的差热分析发现,Mg与SiO2在510～600℃之间发生原位化学反应,生成MgO与Si,被还原的Si继而与过量的Mg反应生成Mg2Si。采用扫描电镜和能谱分析对烧结后试样的微观形态进行分析,结果表明,经超声波辅助电搅拌混料获得的试样,反应所生成的MgO在Mg2Si表面形成了一层致密的团聚体壳层,其与基体之间结合紧密。力学性能测试结果表明,超声波辅助电搅拌混料所获得的试样维氏硬度比电搅拌混料所获得的试样的维氏硬度提高近40%。对体系中自组织反应的反应机理进行了讨论。

纹织CAD中组织合成与分解的实现

为了简化纹织物组织设计,讨论了组织合成与分解一体化的组织设计方法。详细阐述了复杂组织合成与分解的数学模型及实现算法,并基于纹织CAD系统予以实现。实验表明,此方法可提高组织设计的效率和准确性。

合成组织相容性抗原衍生肽延长小鼠移植心肌存活时间的实验研究

目的 :探讨合成组织相容性抗原衍生 (HLA)肽延长小鼠移植心肌存活时间的供者特异性。 方法 :首先将NIH小鼠脾细胞 (5× 10 9/L ,0 2ml)注入Balb/c小鼠尾静脉 ,于注射前 7天、注射当日及之后连续 4天 ,每天给予HLA肽和亚治疗剂量的环胞素A(CsA) ,两周后将NIH和C5 7BL/ 6 (第三者 )新生鼠心肌分别移植于Balb/c小鼠左右耳后 ,不再给予HLA肽和CsA等免疫抑制剂。 结果 :移植与脾细胞同一供者小鼠 (NIH)心肌成活 ,在观察期内 (>2 0天 )未发生排斥反应 ;而移植的第三者 (C5 7BL/ 6 )心肌于移植后第 8天被排斥。 结论 :合成HLA肽加亚治疗剂量的CsA延长小鼠移植心肌存活时间具有供者特异性。

青蒿酸诱导西洋参冠瘿组织生物合成羟基十八碳烯酸(英文)

目的:研究青蒿酸对转基因西洋参(Panax quinquefolium)冠瘿组织次生代谢物生产的影响。方法:青蒿酸西洋参冠瘿组织培养体系中,共培养2 d,终止反应。产物用色谱法进行分离,根据其理化性质及波谱数据对分离所得的化合物进行结构鉴定。结果:分离并鉴定三个羟基十八碳烯酸类化合物,分别为:9,12,13-三羟基-10-十八碳烯酸(1)、11,12,13-三羟基-9-十八碳烯酸(2)和11-羟基-12,13-环氧-9-八碳烯酸(3)。结论:青蒿酸作为一种植物激素可诱导西洋参冠瘿组织培养体系中13-脂氧合酶的表达。

参附注射液对肺组织表面活性物质合成的影响

目的 :探讨参附注射液对肺表面活性物质合成 (PS)的影响。方法 :采用无血清成年大鼠肺组织培养 ,液体闪烁计数测定肺组织 [3H]胆碱掺入量 ,化学定磷法及薄层层析法测定总磷脂 (TPL)及磷脂酰胆碱 (PC)。结果 :参附注射液以剂量依赖方式促进肺组织 [3H]胆碱的掺入 ,并提高肺组织总磷脂、PC的含量及PC/TPL比值 ,该效应可被蛋白激酶C(PKC)抑制剂H7和钙调蛋白抑制剂W7阻断。人参总皂甙及单体Rb1,Rg1均可促进 [3H]胆碱的掺入。结论 :参附注射液可以促进PS的合成 ,其效应有赖于PKC及钙调蛋白的介导 ,人参皂甙是参附注射液促PS合成的有效成分之一。

cathpsin D在多囊卵巢综合征卵巢组织中的表达

目的:检测cathepsin D蛋白在多囊卵巢综合征(polycystic ovarian syndrome,PCOS)患者卵巢组织中的表达。方法:采用Western blot免疫印迹法检测卵巢组织中cathepsin D蛋白的表达,并进行半定量分析;免疫组织化学法观察cathepsin D蛋白的分布定位。结果:PCOS组患者卵巢中cathepsin D蛋白表达显著低于对照组(2.06±0.39 vs 4.76±1.43,P<0.05);cathepsin D在卵泡和卵巢间质细胞上均有表达,其中在卵泡颗粒细胞上染色最深,主要定位在胞浆和胞膜。结论:cathepsin D蛋白在PCOS患者卵巢组织中表达水平显著下调,这可能是PCOS卵泡发育异常的机制之一。

MMP-2与TIMP-2在浸润性乳腺癌组织表达的临床意义及相关性研究

目的 :研究乳腺癌组织中基质金属蛋白酶 (MMP 2 )和金属蛋白酶组织抑制因子(TIMP 2 )的表达与临床病理学特征及预后的关系。方法 :应用SP免疫组化方法检测 78例浸润性乳腺癌组织和 10例乳腺良性病变中MMP 2、TIMP 2的半定量表达情况。结果 :1)在78例乳腺癌组织中 ,MMP 2、TIMP 2的阳性表达率分别为 74 3 % ( 5 8/78)和 3 9 7% ( 3 1/78) ,与对照组比较差异有统计学意义 ,P <0 0 1;两者表达呈负相关 ,rs=-0 43 7,P <0 0 1。 2 )MMP 2表达与乳腺癌原发肿瘤大小呈显著正相关 ,rs=0 3 74,P <0 0 1,与组织学分级相关 ,分级越高其阳性表达率就越高 ,rs=0 60 6,P <0 0 1;TIMP 2的表达与肿瘤大小呈负相关rs=-0 2 88,P <0 0 5 ;与组织学分级呈负相关 ,rs=-0 3 77,P <0 0 1。MMP 2阳性表达与腋窝淋巴结转移呈正相关 ,rs=0 45 4,P <0 0 1;TIMP 2的表达与腋窝淋巴结转移呈负相关 ,rs=-0 2 61,P<0 0 5。MMP 2阳性表达与 5年生存率呈负相关 ,P <0 0 1;TIMP 2与 5年生存率呈正相关 ,P<0 0 1。结论 :乳腺癌组织中MMP 2与TIMP 2的表达与肿瘤转移及患者预后密切相关。

聚-4-羟基丁酸的微生物合成及医学应用

聚-4-羟基丁酸[P(4HB)]是由微生物在非平衡生长条件下胞内积累的高分子聚酯,具有高柔韧性、生物相容性、生物可降解性、热塑性等特点。P(4HB)作为可吸收材料可用于制备医用可植入器件,如制备补片、心脏瓣膜和人造血管等治疗心血管疾病;制备手术缝合线;制备软组织修复材料;用于药物缓释体系。研究表明,生物发酵合成的P(4HB)是一种优良的医用生物材料。

Effect of cold rolling deformation on microstructure evolution and mechanical properties of spray formed Al−Zn−Mg−Cu−Cr alloys

The impact of cold rolling deformation,which was introduced after solid solution and before aging treatment,on microstructure evolution and mechanical properties of the as-extruded spray formed Al−9.8Zn−2.3Mg−1.73Cu−0.13Cr(wt.%)alloy,was investigated.SEM,TEM,and EBSD were used to analyze the microstructures,and tensile tests were conducted to assess mechanical properties.The results indicate that the D1-T6 sample,subjected to 25%cold rolling deformation,exhibits finer grains(3.35μm)compared to the D0-T6 sample(grain size of 4.23μm)without cold rolling.Cold rolling refines the grains that grow in solution treatment.Due to the combined effects of finer and more dispersed precipitates,higher dislocation density and smaller grains,the yield strength and ultimate tensile strength of the D1-T6 sample can reach 663 and 737 MPa,respectively.In comparison to the as-extruded and D0-T6 samples,the yield strength of the D1-T6 sample increases by 415 and 92 MPa,respectively.

Tensile and wear properties of TiC reinforced 420 stainless steel fabricated by in situ synthesis

TiC particle reinforced 420 stainless steel matrix composites were fabricated, and the microstructure, tensile properties and wear resistance of the composites were studied. The experimental results indicate that the distribution of TiC particles with size of 5 to 10 μm in diameter is uniform if the volume fraction of TiC is lower than 6%. However, slight agglomeration can be observed when the TiC content exceeds 6%. With the increase of TiC content the tensile and yield strength of the composites prepared increases and reaches the maximum when the volume fraction of TiC increases to 5%. Further increase of TiC content causes reductions of yield and tensile strength. The ductility of the composites shows a monotone decrease with the increase of TiC addition. The introduction of TiC into 420 stainless steel results in significant improvement on wear resistance, which reaches a steady level when the volume fraction of TiC increases to 11% and does not show obvious variation if the TiC content is further increased.

AC算法的EMD分解GMDH组合的预测模型及应用

引入EMD把含有多个震荡模式的数据分解为满足一定条件的多个单一震荡模式分量的线性叠加,对震荡模式分量应用非参数的AC算法,通过历史上相似时期的已知延拓进行预测,利用GMDH客观确定权重构建组合预测模型,并运用该模型结合原油期货数据进行实证。结果表明:用EMD方法改进AC预测模型提高了预测的准确性,在此基础上,GMDH的智能化权重的组合预测模型进行预测,结果显示,AC算法的EMD分解GMDH智能化权重组合预测精度更高。

Microstructure evolution and nitrides precipitation in in-situ Ti_2 AlN/TiAl composites during isothermal aging at 900°C

Microstructures of Ti2AlN/TiAl composites prepared by in-situ method were characterized in in-situ and aging treatment conditions and the nitride precipitation was investigated in Ti2AlN/TiAl composites aged at 900 ℃ for 24 h after being heat treated at 1400 ℃ for 0.5 h. The in-situ composites consist of γ＋α2 lamellar colonies, equiaxed y grains and Ti2AlN reinforcements. Matrix with nearly fully lamellar structure formed after solution and subsequently aging treatment. With the increase of Ti2AlN content, the nearly fully lamellar structure becomes instable for the aged composites. According to TEM study, fine Ti2AlN precipitates are found to distribute at the grain boundaries of lamellar colony. Needle-like Ti3AlN precipitates arrange in line with growing axis parallel to [001] direction of the γ-TiAl matrix and another needle-like Ti3AlN precipitates with lager size distribute at the dislocations. Key words：

Microstructure and evolution of(TiB_2+Al_2O_3)/NiAl composites prepared by self-propagation high-temperature synthesis

（TiB2＋Al2O3）/NiAl composites were synthesized by self-propagation high-temperature synthesis, and their phase compositions, microstructures and evolution modes were studied. The microstructures and shapes vary with the TiB2＋Al2O3 content in the NiAl matrix. TiB2 particles take a great variety of elementary shapes such as white bars, plates, herringbones, regular cubes and cuboids. These results outline a strategy of self-assembly processes in real time to build diversified microstructures. Some TiB2 grains in sizes of 2-5μm are embeded in Al2O3 clusters, while a small number of TiB2 particles disperse in the NiAl matrix. It is believed that the higher the TiB2＋Al2O3 content is, the more the regular shapes and homogeneous distributions of TiB2 and Al2O3 will be present in the NiAl matrix.

Microstructure control of AZ31 alloy by self-inoculation method for semisolid rheocasting

A novel rheocasting process, self-inoculation method （SIM）, was developed for the microstructure control of semisolid wrought Mg alloy. This process involves mixing between liquid alloy and particles of solid alloy （self-inoculants）, subsequently pouring the mixed melt into a special designed multi-stream fluid director. The primary phase with dendritic morphology in the conventionally cast AZ31 alloy has readily transformed into near spherical one in the slurry produced by SIM from melt treatment temperature between 690 ℃ and 710 ℃ and self-inoculants addition of 3%-7%. Achievement of the non-dendritic microstructure at the higher melt treatment temperature requires more self-inoculants addition or decreases in the slope angle of fluid director. Primary phase in the slurry thus produced has attained an ideally globular morphology after isothermal holding at 620 ℃ for 30 s. The increasing holding time leads to decrease of shape factor but the coarsening of particle size. The spheroidization and coarsening evolution process of solid particles during the isothermal holding were analyzed by Lifshitz-Slyozov-Wagner （LSW） theory.

Morphology and crystallography of β precipitate phase in Mg-Gd-Y-Nd-Zr alloy

Morphology and crystal structure of β precipitate phase in Mg-7Gd-5Y-1Nd-0.5Zr (mass fraction, %) alloy were characterized by optical microscopy, scanning electron microscopy and transmission electron microscopy. Compositions were determined for β phase using thin foil energy dispersive spectroscopy. Precipitation at 400 ℃ involves formation of platelet and block-shaped β phase. The orientation relationship is and between β precipitate phase and α-Mg matrix with habit planes parallel to , and a composition of Mg5(Y0.4Gd0.4Nd0.2) is suggested for the β phase in Mg-7Gd-5Y-1Nd-0.5Zr alloy.

Effect of extrusion process on microstructure and mechanical properties of Ni_3Al-B-Cr alloy during self-propagation high-temperature synthesis

The well-densified Ni3Al-0.5B-5Cr alloy was fabricated by self-propagation high-temperature synthesis and extrusion technique. Microstructure examination shows that the synthesized alloy has fine microstructure and contains Ni3Al, Al2O3, Ni3B and Cr3Ni2 phases. Moreover, the self-propagation high-temperature synthesis and extrusion lead to great deformation and recrystallization in the alloy, which helps to refine the microstructure and weaken the misorientation. In addition, the subsequent extrusion procedure redistributes the Al2O3 particles and eliminates the γ-Ni phase. Compared with the alloy synthesized without extrusion, the Ni3Al-0.5B-5Cr alloy fabricated by self-propagation high-temperature synthesis and extrusion has better room temperature mechanical properties, which should be ascribed to the microstructure evolution.

Microstructure and defect of titanium alloy electron beam deep penetration welded joint

The microstructure, phase composition and cold shut defect of thick titanium alloy electron beam welded joint were studied. The results showed that the microstructure of weld zone was composed of α′ phase; the heat affected zone was divided into fine-grained zone and coarse-grained zone, the microstructure of fine-grained zone was primary α phase ＋ β phase ＋ equiaxed α phase, and the microstructure of coarse-grained zone was primary α phase ＋ acicular α′ phase; the microstructure of base metal zone basically consisted of primary α phase, and a small amount of residual β phase sprinkled. The forming. reason of cold shut was analyzed, and the precaution of cold shut was proposed.

Microstructure and phase composition of as-cast Mg-9Er-6Y-xZn-0.6Zr alloys

The microstructure and phase composition of as-cast Mg-9Er-6Y-xZn-0.6Zr （x=1, 2, 3, 4; normal mass fraction in %） alloys were investigated. In low Zn content, aside from the major second phase of Mg24（Er, Y, Zn）5, there are a few lamellar phases that grow parallel with each other from the grain boundaries to the grain interior. With Zn content increasing, the Mg24（Er, Y, Zn）5 phase decreases, but the Mg12Zn（Y, Er） phase and lamellar phases continuously increase. When Zn content reaches 4% （normal mass fraction）, the Mg12Zn（Y, Er） phase mainly exists as large bulks, and some a-Mg grains are thoroughly penetrated by the lamellar phases. Moreover, the crystallography structures of the Mgl2Zn（Y, Er） and Mg24（Er, Y, Zn）5 phases are confirmed as 18R-type long-period stacking ordered structure and body-centred cubic structure, respectively.

检测基质金属蛋白酶及其抑制物对判断膀胱癌侵袭和转移的意义

目的 :研究基质金属蛋白酶 (MMPs)中MMP 2、MMP 9及MMP 9抑制物TIMP 1在膀胱移行细胞癌中的表达情况及其在判断膀胱癌侵袭转移中的作用。方法 :应用免疫组化LSAB法检测 90例膀胱移行细胞癌 (transitionalcellcarcinomaofbladder,TCCB)组织中MMP 2、MMP 9和TIMP 1蛋白表达水平。结果 :膀胱癌组织中MMP 2、MMP 9和TIMP 1蛋白表达显著高于正常膀胱黏膜。浸润性膀胱癌组织中阳性表达显著高于表浅性膀胱癌组织。阳性表达细胞在肿瘤 -间质界面较多。与病理组织学分级、分期均呈正相关 ;与肿瘤的复发和转移呈正相关。结论 :MMP 2、MMP 9和TIMP 1参与膀胱癌侵袭转移 ,在膀胱移行细胞癌中的表达具有预后价值。