Improving chill control in iron powder treated slightly hypereutectic grey cast irons

Recent studies revealed that in eutectic to slightly hypereutectic grey irons （CE = 4.3%-4.5%） the presence of austenite dendrites provides an opportunity to improve the cast iron properties, as a high number of eutectic cells are ＂reinforced＂ by austenite dendrites. An iron powder addition proved to be important by promoting dendritic austenite in hypereutectic irons, but was accompanied by adverse effect on the characteristics of potential nuclei for graphite. The purpose of the present paper is to investigate the solidification pattern of these irons. Chill wedges with different cooling moduli （CM = 0.11 - 0.43 cm） were poured in resin bonded sand and metal moulds. Relative clear / mottled / total chill measurement criteria were applied. Iron powder additions led to a higher chill tendency, while single inoculation showed the strongest graphiUzing effect. The various double treatments show an intermediate position, but the inoculant added after iron powder appears to be the most effective in reducing base iron chill tendency, for all cooling moduli and chill evaluation parameters. This performance reflects the improved properties of （Mn,X）S polygonal compounds as nucleation sites for graphite, especially in resin bonded sand mould castings. Both austenite and graphite nucleation benefit from a double addition of iron powder ＋ inoculant, with positive effect on the final structure and chill tendency.

Cold-state spout-fluidizing characteristics of high-carbon ferromanganese powders

The spout-fluidizing characteristics of high-carbon ferromanganese powders with different sizes and masses were studied via a plexiglass spout-fluidized bed with an inner diameter of 30 mm and a height of 1000 mm.The relationships between bed voidage and such parameters as bed height,particle size,fluidizing air velocity,and air flow were obtained.Experimental results show that the powder material with high density can be fluidized in the spout-fluidized bed where the particle size is a key factor influencing the quality of fluidization.

Zhichan powder regulates nigrostriatal dopamine synthesis and metabolism in Parkinson's disease rats

In this study, rat models of Parkinson＇s disease induced by substantia nigra injection of 6-hydroxy-dopamine were intragastrically administered Zhichan powder daily for 50 days. Reverse transcription PCR results showed that tyrosine hydroxylase mRNA expression in the rat substantia nigra was significantly increased, while monoamine oxidase B mRNA expression was significantly decreased in the Zhichan powder group, compared with the model group. In addition, the levels of striatal dopamine and homovanillic acid, the ratio of dopamine to homovanillic acid, and the activity of blood superoxide dismutase were all higher in the Zhichan powder group than in the model group but the content of malondialdehyde in blood was lower. Our experimental findings indicate that Zhichan powder has an antioxidant effect, it can regulate the expression of monoamine oxidase B and tyrosine hydroxylase in the substantia nigra of Parkinson＇s disease rats, and it can facilitate the secretion of striatal dopamine and its metabolite homovanillic acid.

Effects of Zhichan powder on signal transduction and apoptosis-associated gene expression in the substantia nigra of Parkinson's disease rats

Previous studies have shown that Zhichan powder elevated immunity and suppressed oxidation in mice. Rat models of Parkinson＇s disease were induced by stereotaxically injecting 6-hydroxydopamine into the substantia nigra. The rat models were intragastrically treated with Zhichan powder, which is composed of milkvetch root, ginseng, bunge swallowwort root, himalayan teasel root. Magnolia officinalis, Ligustrum lucidum Ait. and szechwan Iovage rhizome. Immunohistochemistry and reverse transcription-PCR results demonstrated that mRNA and protein expression of tumor necrosis factor receptor 1, Fas, caspase-8, cvtochrome C, Bax, casDase-3, and p53 significantly increased, but Bcl-2 expression significantly decreased in the substantia nigra of rats with Parkinson＇s disease. Following Zhichan powder administration, mRNA and protein expression of tumor necrosis factor receptor 1, Fas, caspase-8, cytochrome C, Bax, caspase-3, and p53 diminished, but Bcl-2 expression increased in the rat substantia nigra. These results indicate that Zhichan powder regulates signal transduction protein expression, inhibits apoptosis, and exerts therapeutic effects on Parkinson＇s disease.

Characterization of functionally graded ZrO_2 thermal barrier coatings sprayed by supersonic plasma spray with dual powder feed ports

The functionally graded thermal barrier coatings （FG-TBCs） with 80%ZrO2-13%CeO2-7%Y2O3 （C-YSZ）/NiCoCrAlY were prepared using a recently developed supersonic plasma spraying（S-PS） with dual powder feed ports system. The thermal shock experiment of FG-TBCs specimens was carried out by means of the automatic thermal cycle device, in which the samples were heated to 1200℃ by oxygen-acetylene flame jet then water-quenched to ambient temperature. The temperature—time curves of specimens and photographs can be watched on-line and recorded by a computer during the test. The results show that the totally 1mm-thick FG-TBCs have excellent thermal shock resistance due to the fact that the coatings have no any peeling-off after 200 thermal cycles. The microstructures and morphologies of FG-TBCs were characterized and analyzed by SEM.

Network pharmacological analysis on the active ingredients of Yigan Powder in treating Alzheimer's disease with depressive disorder

Objective:To study the potential therapeutic effect of Yigan Powder on Alzheimer’s disease(AD)comorbid Depressive Disorder with Network Pharmacology.Methods:The active ingredients of Yigan Powder were screened from Traditional Chinese Medicine Systems Pharmacology database and analysis platform(TCMSP)by ADME parameters,targets are predicted by Swiss Target Prediction database,disease targets are downloaded from GeneCards,OMIM and PharGKB database.Using R to run GO terms enrichment and KEGG pathway enrichment analysis.Protein interaction data is downloaded from the String database.Cytoscape software is used to build network.AutoDock Vina and PyMOL software are used for molecular docking.Results:There are 125 active ingredients in Yigan Powder with 953 predicted targets,85 of predicted targets are related to Alzheimer's Disease comorbid Depressive Disorder,shows highly enriched signaling pathways and biological processes.PPI network shows APP,MAPK1 and STAT3 may be important potential treatment of Alzheimer's Disease comorbid Depressive Disorder.The results of AutoDock Vina docking showed that the active ingredients of Yigan Powder had good binding activity with important receptors.Conclusion:Yigan Powder shows effect on neurotransmitter metabolism,synaptic transmission,neuroinflammation and other aspects in the treatment of Alzheimer's Disease comorbid Depressive Disorder.

SAC-P·Ⅱ体系对废旧混凝土再生砂粉制备的灌浆材料性能研究

以SAC-P·Ⅱ(硫铝酸盐-Ⅱ型硅酸盐水泥)复合体系为胶凝材料,对以废旧混凝土再生砂粉作为骨料制备水泥基灌浆材料的流动度、抗折抗压强度、拉伸粘结强度、泌水率及竖向膨胀率等性能的影响研究。结果表明:随着SAC水泥掺入比例的增加,30min流动度明显降低,1d和3d抗折及抗压强度增幅较大,而28d抗折及抗压强度则增长幅度不大;P·Ⅱ水泥收缩较大,SAC水泥具有微膨胀性能,故SAC水泥比例越高,同等膨胀剂用量条件下,竖向膨胀率增大,反之降低;同等胶凝材料用量下,SAC水泥比例高,拉伸粘结原强度、浸水后及热老化均表现为降低,与扫描电子显微镜(SEM)微观结构显示一致;综合考虑各项性能,推荐SAC-P·Ⅱ复合体系灌浆料中SAC水泥比例为不超过80%。

CaO-Al_2O_3-SiO_2系统烧结建筑微晶玻璃颗粒高温摊平影响因素研究

烧结法微晶玻璃装饰板材是一种新型建筑装饰材料。其表面花纹的大小由表面玻璃颗粒度所决定。玻璃颗粒度不同对烧结法微晶玻璃的表面性能会产生不同的影响。本文利用正交实验研究了影响烧结法微晶玻璃颗粒高温摊平的因素。对玻璃颗粒的高温摊平的影响顺序为:烧成温度、成分(CaO/Al2O3)、颗粒度和烧成时间。在成分、烧成时间不变的前提下,玻璃颗粒的平均粒径增加2mm,其烧成温度需提高5～8℃。在成分、烧成温度不变的前提下,玻璃颗粒的平均粒径增加2mm,其烧成时间需增长20～30min。

粉末SBR-g-s的制备及其对PS的增韧作用

用凝聚法制备了粒径小于１ｍｍ的粉末ＳＢＲｇｓ。研究了粉末ＳＢＲｇｓ对ＰＳ的增韧效果。结果发现粉末ＳＢＲｇｓ与ＰＳ共混体的冲击强度与ＳＢＲｇｓ的交联程度、接枝率和组成比有关。当ＳＢＲｇｓ的溶胀指数为２４３，接枝率为２８１％，ＳＢＲ／ｇｓ的比率为６５／３５（质量）时对ＰＳ有良好的增韧效果。当这种粉末ＳＢＲｇｓ与ＰＳ的共混比为３５／６５（质量），其共混体的冲击强度可达４８５ｋＪ／ｍ２（无缺口）。

Effects of PVP K30 on Aqueous Solubility and Dissolution Propertiesof Daidzein

AimTo study effects of PVP K30 on the aque ou s solubility and dissolution properties of daidzein. Methods To measure the aqueous solubility and dissolution rates of daidzein in three diffe rent states (within solid dispersions, physical mixtures and as a pure drug) and investigate drug-polymer interactions in the solid state using X-ray powder d iffraction and fourier-transform infrared spectroscopy. Results The negative values of the Gibbs free energy and enthalpy of transfer explaine d the spontaneous transfer of daidzein from phosphate buffer solution (PBS) to a solution of PVP in PBS. X-ray powder diffraction patterns showed that the drug was in the amorphous state (ratio of the drug ∶ PVP<1∶5) when dispers ed i n PVP K30. The infrared spectra indicated there exist interactions between the O H of daidzein and the C=O of PVP K30. Conclusionthe dispersion of daidzein in PVP K30 considerably enhances the solubility and dissolution rat e.

小鼠S_(180)肉瘤细胞热损伤的机制研究

目的 通过测定肿瘤细胞内游离钙离子浓度 ([Ca2 + ]i)及细胞膜脂流动性的变化 ,探讨肿瘤细胞热损伤的机制。方法 对体外培养的小鼠S180 肉瘤细胞进行高温 (4 3℃、60min)处理后 ,利用激光粘附式细胞仪测定肿瘤 [Ca2 + ]i的荧光强度及膜脂扩散系数 ,并观察细胞的形态学变化。结果 受热损伤的肿瘤 [Ca2 + ]i荧光强度为 (10 3 80± 14 0 9) ,比对照组的荧光强度 (94 3 4± 13 99)升高 (P <0 0 1) ;膜脂流动性为 (7 40± 6 84)× 10 -5cm2 /s ,比对照组的 (10 5 3± 6 92 )× 10 -5cm2 /s下降 (P <0 0 1) ;经高温处理后细胞形态学改变明显 ,肉瘤细胞变形、膜皱缩、不规整 ,胞质不均 ,有颗粒状物 ,细胞核散乱、有大量空泡 ,与对照组有明显区别。结论 高温使肿瘤细胞形态发生变化 ,改变了细胞膜的结构 ,导致[Ca2 + ]i升高 ,提示 [Ca2 +

富碳无定形SiC超微粉预氧化及高温脱碳脱氧结晶化工艺研究

对于含有大量残碳的无定形ＳｉＣ超微粉，采用预氧化，高温脱碳脱氧结晶化处理工艺可以制备出纯度较高的β－ＳｉＣ超微粉。在预氧化过程中，定量引入氧原子，使微粉中的残碳与氧的原子比接近理论比值１：１，然后在高温过程中使残碳与氧发生固相反应。探讨了实验条件下温度、气氛等反应条件对产物性质的影响，并对其反应机理进行了讨论。

氮化硅-氧氮化硅复合粉对Al2O3-SiC-C铁沟料性能的影响

为了进一步提高Al 2O3-SiC-C出铁沟浇注料的性能并降低其生产成本,在其中加入质量分数分别为0、2%、4%、6%、8%的氮化硅-氧氮化硅复合粉等量替代其中的碳化硅粉,加水搅拌均匀后,检测料浆的流动性,再经浇注成型、养护、烘干、不同温度(800、1100和1450℃)热处理等程序制成浇注料试样,然后检测浇注料试样的线变化率、显气孔率、体积密度、常温抗折强度、热态抗折强度和抗渣性,并采用XRD分析浇注料试样的物相组成。结果表明:1、加入氮化硅-氧氮化硅复合粉后,Al 2O3-SiC-C出铁沟浇注料的初始流动值减小,烧后线变化率、显气孔率、体积密度、常温抗折强度和热态抗折强度变化不大,抗高炉渣侵蚀性提高。2、综合考虑,氮化硅-氧氮化硅复合粉的最佳加入量为4%(w)。

水溶性新显色剂5-Br-PADN-S的制备与分析特性的研究及其用于锌的测定

报道了水溶性 １－（５－溴－２－吡啶偶氮）－２，７－萘二酚－６－磺酸（５－Ｂｒ－ＰＡＤＮ－Ｓ）的制备方法及其分析特性。研究了此试剂与锌（Ⅱ）等金属离子在水溶液中直接测定的显色反应，在ｐＨ １０．０～１１．４ 的Ｎａ２Ｂ４Ｏ７～ＮａＯＨ 缓冲溶液中，５－Ｂｒ－ＰＡＤＮ－Ｓ与锌（Ⅱ）形成２∶１ 的紫色配合物，最大吸收波长位于５４２ ｎｍ ，表观摩尔吸光系数ε５４２＝ ６．３８×１０４ Ｌ／（ｍ ｏｌ·ｃｍ ），锌量在０～２０ ｍ ｇ／１０ Ｌ范围内符合比耳定律。在掩蔽剂的存在下，用于人发、奶粉及矿石等试样中锌的测定，结果与ＡＡＳ法一致。

高纯二氧化硅微粉含量对Al_2O_3-SiC-C铁沟渣线浇注料性能的影响

以棕刚玉颗粒(15～8 mm,8～5 mm,5～3 mm,3～1 mm),板状烧结刚玉(1～0 mm),碳化硅(3～1 mm,≤1 mm,≤0. 063 mm)、白刚玉粉,活性氧化铝微粉和高纯二氧化硅微粉以及单质硅粉和球状沥青等为主要原料,制备了出铁沟渣线用Al_2O_3-SiC-C质浇注料,并研究了高纯硅微粉含量对其流动性及高温使用性能的影响。结果表明:随高纯硅微粉含量的增加,浇注料的初始流动性基本呈增加趋势,且其流动值的保持时间延长。随高纯硅微粉含量的增加,浇注料的热态抗折强度呈增加趋势,且抗侵蚀性也会增强。

溶胶－凝胶法制备SiC－AIN复合超细粉末的研究

用溶胶－凝胶碳热氮化法在１５５０～１６５０℃，５０ｍｉｎ下制得平均粒径为０．２μｍ左右的ＳｉＣ－ＡＩＮ复合超细粉末，粉末烧结性能良好；在较低合成温度下（１５５０～１６００℃），粉末中出现晶须。本研究还探讨了粉末氨化合成条件对粉末颗粒及物相的影响。

半导体用高纯超细SiC粉体的表面改性

通过偶联剂预处理、接枝聚合丙烯酸钠两步法对SiC粉体进行表面改性,制备聚丙烯酸钠接枝改性SiC粉体,并对改性粉体进行表征,测试SiC粉体的zeta电位,讨论改性对SiC粉体料浆分散稳定性和流动性的影响。结果表明:SiC微粉经表面改性后并未改变原始SiC微粉的物相结构,只是改变其在水中的胶体性质;微粉团聚现象减少,分散性得到改善;改性SiC微粉与原始SiC微粉相比,表面特性发生很大变化,zeta电位值显著提高,悬浮液的分散稳定性得到明显改善,且黏度降低。

PS/粉末SBR-g-S共混体研究Ⅱ.粉末SBR-g-S的相结构及其与PS的相容性

测定了 SBR- g- S的接枝率 ,用 TEM检测了粉末 SBR- g- S(PR)的相结构。用 DSC测定了 PS/ PR共混体的Tg,研究了 PS/ PR共混体的相容性。结果发现 ,在接枝率为 32 .6 %的粉末非交联 SBR- g- S(PR1 )的相结构中 SBR为连续相 ,在连续相中均匀分布着直径约 0 .0 1μm的 PS微区 ;PS为细胞状分散相 ,粒径 1～ 5μm,分散相含有SBR包藏物。在接枝率为 8.5 %的粉末交联 SBR- g- S(PR2 )的相结构中 PS为连续相 ,SBR为分散相 ,分散相粒径约0 .3μm。共混体 PS/ PR1 的相容性优于 PS/ PR2 。 SBR在 PS富相中有较高的含量是导致 PS/ PR1 共混体在冲击断裂时发生剪切屈服的主要原因。

S_(3307)乳剂和可湿性粉剂对稻苗的生理影响

Ｓ３３０７，稀效唑，英文名Ｕｎｉｃｏｎｚｏｌｅ，是８０年代初期由日本住友公司推出的三唑类新型的植物生长调节剂。它具有高效、低毒、低残留的特点，在农业生产上的应用有广阔的前景［１，２］。用Ｓ３３０７浸种，处理之后的稻苗表现为矮壮、根冠比增大、叶色深绿，...

负载茜素红S的纳米磁性碳粉修饰电极测定牛白蛋白

采用化学沉积法在纳米碳粉上合成磁性Fe3O4颗粒，纳米碳粉吸附茜素红S后通过磁力附着在石墨电极上，制成了负载茜素红S的纳米磁性碳粉修饰电极。研究了该电极在0．014mol／LH2SO4-0．2mol／LKCl溶液中对ARS-牛白蛋白的电还原作用，考察了多种实验条件对峰电流的影响。在-0．45V电位下，牛白蛋白浓度在1．5×10^-8～9×10^-7mol／L范围内与线性扫描伏安法还原电流成反比，从而实现对牛白蛋白的测定，并初步研究了电化学反应机理。此方法制成的磁性纳米颗粒修饰电极集分离、富集、测定和更新于一体，具有更新方便的特点。