Selective catalytic NOx reduction on Antimony promoted V2O5-Sb/TiO2 catalyst

Quantum chemical calculation was carried out to choose a promoter which can reduce the poisoning of V2O5/TiO2 catalysts by SO2.Several atoms were chosen as candidates and new catalysts were synthesized by impregnation method.The NOx conversion rate was measured at temperatures between 100 and 400 ℃ and poisoning effect was investigated.The most promising candidate promoter, Se, was excluded because of its high vapor pressure.On the other hand, Sb shows best promoting properties.Sb promoted catalyst reaches the maximum NOx conversion rate at 250 ℃.It also shows considerably enhanced resistance to poisoning of V2O5/TiO2 catalysts by SO2.     

蜂窝状筛网催化剂上NH_3选择性催化还原NO的工艺特性

采用蜂窝状筛网催化剂进行NH3选择性催化还原NO的反应 ,考察了温度、空速、进料比及进料气、氧、水含量等因素对其催化性能的影响。结果表明 :进料气含量和进料比的增加均可提高NO的转化率 ;体积分数 2 %的氧便可封闭催化循环 ,显著提高NO转化率 ;当水体积分数在 2 %以内时 ,水的添加将导致NO转化率的降低。蜂窝状筛网催化剂与蜂窝状堇青石催化剂相比 ,具有优异的非稳态响应特性 ,反应可在较短的时间内进入稳态     

Volatile Components in Blue Crab (Callinectes sapidus) Meat and Processing By-Product

Volatile components in fresh-picked blue crabmeat and processing byproduct were compared by simultaneous steam distillation-solvent extraction/gas chromatography/mass spectrometry (SDE/GC/MS). Compounds were identified in crabmeat (771 and by-product (80) of which 58 were common to both. Some compounds 154) were identified for the first time in crab. Trimethylamine, four alkanes (C15–C17, C19), and indole were highest (> 50 ng/g)) in crabmeat, while trimethylamine, carbon disulfide, dimethyltrisulfide, two alkanes (C15 and C17), geranylacetone, and 1–dodecanol were highest in by-product. Of compounds from both samples, 23 were higher in by-product and 7 were higher in the meat. Crab processing by-product may be a good source for volatile flavor recovery.     

梯度孔隙率与大孔隙尺寸NiTi形状记忆合金的制备及其相变和超弹性行为

利用低温分解型造孔剂与梯级热等静压烧结和常规烧结的匹配工艺成功制备出了梯度孔隙率与大孔隙尺寸多孔NiTi形状记忆合金.多孔合金的孔隙率为30%-61%,孔隙平均尺寸可根据不同预处理工艺在50-500 μm之间变化,且具有较高的开孔率(最高可达85%).所制备的径向梯度孔隙率多孔NiTi合金具有良好的力学性能,线性超弹性应变大于4%;热分析和XRD分析表明,所制备的多孔合金呈现明显的马氏体转变和逆转变特征,相变特征温度随孔隙率的提高而降低.     

D-Erythroascorbic Acid in Bakers'Yeast and Effects on Wheat Dough

Extraction of hydrated and freeze-dried bakers’yeast yielded ～ 50 μg erythroascorbic acid (EAA) and 5 μg ascorbic acid (AA)/g dry yeast as determined by HPLC with electrochemical detection. D-EAA (82 ppm based on flour) slightly increased the flow of dough as rest time increased. Gluten isolated from a flour-water dough containing 82 ppm D-EAA or 100 ppm Lcysteine stretched at a faster rate than control gluten. EAA like AA did not change dough development time. Unlike AA, EAA showed neither oxidizing effect on dough and gluten nor improving effects on bread.     

Cooked Blue Crab Claw Meat Aroma Compared with Lump Meat

Sensory evaluation of claw and lump crabmeats by sniffing indicated no aroma difference (p > 0.05); however, differences (p < 0.05) were found between the taste and aromatics of aqueous extracts of both meats. Eleven aroma notes (combined total) were found in the meats by aroma extract dilution analysis (AEDA). Flavor dilution factors for compounds common to both meats were not statistically different (p > 0.05). Aroma notes found to have highest intensity in both meats were: meaty/salty/soy sauce [3-(methylthio)-propanal], sweet/fruity, metallic/rubber/gasoline, nutty/popcorn [2-acetyl-l-pyrroline], nutty/popcorn, pine/sweet/hay/dry seaweed, and mushroom/solvent.     

Titanium diboride copper-matrix composites

Copper-matrix titanium diboride platelet (3–5 μm) composites containing 15–60 vol% TiB2, were fabricated by powder metallurgy, using copper-coated TiB2 (60 vol% TiB2) and various amounts of copper powder. The porosity was ≤0.5% when TiB2 was ≤48 vol%. Above 48 vol% TiB2, the porosity increased abruptly with increasing TiB2 content, reaching 6.7% at 60 vol% TiB2. As a result, the hardness and compressive yield strength dropped precipitously with increasing TiB2 volume fraction beyond 48%. At 48 vol% TiB2, the thermal conductivity was 176 W m-1°C-1, the electrical resistivity was 3.42× 10-6Ωcm, the coefficient of thermal expansion (CTE) was 10.2×10-6°C-1, the compressive yield strength was 659 MPa, and the Brinell hardness was 218. For composites made by conventional powder metallurgy, using a mixture of TiB2 platelets (not coated) and copper powder, the porosity was ≤1.8% when TiB2 was at ≤42 vol%; above 42 vol% TiB2, the porosity increased abruptly and the hardness and compressive yield strength decreased abruptly. The electrical resistivity and thermal conductivity were also affected by the porosity, but less so than the mechanical properties. Composites made using copper-coated TiB2 exhibited lower electrical resistivity, higher thermal conductivity, lower CTE, higher compressive yield strength, greater hardness, greater abrasive wear resistance, greater scratch resistance and lower porosity than the corresponding composites made from uncoated TiB2. This revised version was published online in November 2006 with corrections to the Cover Date.