纳米二氧化钛光催化降解毒死蜱的动力学研究

以高压汞灯为光源,研究纳米二氧化钛(TiO2)降解毒死蜱的反应动力学,考察纳米TiO2用量、毒死蜱起始质量浓度及溶液pH值对毒死蜱光催化降解速率的影响.结果表明,纳米TiO2最佳用量为50～100 mg/L,毒死蜱初始质量浓度在5～80 mg/L时,其降解反应符合一级反应动力学规律,表现为毒死蜱质量浓度越大,降解速率常...     

Phase Transformation Diffusion Bonding of Titanium Alloy to Stainless Steel

Jointing of titanium alloy and stainless steel is very often in the fields like aviation, chemical plants etc. The combination of materials has the advantages of both titanium alloy and stainless steel and will reduce the consumption of titanium resource. The phase transformation diffusion bonding of TA17 titanium alloy to 0CriSNigTi stainless steel are carried out on Gleeble - 1500D. The effcet of maximum thermal cycle temperature, the tensile strength, the fracture surface and microstruture of the joints are investigated. The results show that TiFe and TiFe2 intermetallics and some solid solutions are formed along the interface, when maximum thermal cycle temperature increase, the area proportion of intermetallics in the fracture surface increase, which are detrimental to the mechanical properties of the transition joints.     

DETERMINATION OF METALLIC IRON IN HIGH TITANIUM SLAG BY HEADSPACE GAS CHROMATNGRALHY

The following details are discussed in the present paper, after high titanium slag and H3PO4 is put in the closed system,the .reaction takes place under controlled temperature conditions, and the gas produced is collected. The two phases of gas liquid attain kinetic equilibrium, ihe gas above the liquid is used to make GC analysis with the aid of chromatographic column of 5A molecular sieve, TCD and N2 30ml/min. Satisfactory quantitative results can be achieved with simple instruments and uncomplicated operation technique.     

真空碳热还原酸浸含钛高炉渣制备TiC分析

含钛高炉渣中含有20%~30%的TiO 2,是一种附加值较高的二次资源,但在综合利用过程中存在氧化物还原难度大,硅钛难分离,二次污染严重等问题。基于热力学理论基础,采用真空碳热还原联合酸浸工艺处理含钛高炉渣制备TiC。结果表明：真空有助于钛氧化物彻底还原,可实现渣中硅钛彻底分离,减少酸耗量,降低二次污染。真空碳热还原联合酸浸工艺处理含钛高炉渣(TiO 2含量23%左右)制备TiC的最佳条件为：炉渣粒度200目,还原温度1 673 K,渣碳质量比100∶38。     

空气净化网上光催化剂和活性炭相互增强净化能力的作用机理

采用浸涂法在活性炭空气净化网上负载纳米二氧化钛，在紫外光的照射下，净化网对一氧化碳、甲醛、硫化氢等污染物的净化能力明显增强，对比实验表明，在紫外光照射下光催化剂使被吸附的污染物发生降解反应而提高活性炭的净化能力。活性 吸附作用为光催化反应浓度环境，加速反应速率。     

Phytotoxicity of cobalt,vanadium, titanium,silver, and chromium

Abstract

The phytotoxicity of five nonessential elements (Co, V, Ti, Ag, Cr) to higher plants was studied in solution culture experiments with bush beans (Phaseolus vulgaris L. C.V. Improved Tendergreen). All, but in varying degrees, tended to concentrate in roots with a decreasing gradient to stems and leaves. Cobalt was one of the more mobile of the five trace metals. Its toxicity was expressed as severe chlorosis; 43 (with 10^‐5 M) and 142 (with 10^‐4 M) μg Co/g dry weight in leaves resulted in severe chlorosis. Vanadium as 10^‐4 M vanadate resulted in smaller plants but not in chlorosis. Leaf, stem, and root V, respectively, were 13, 8, and 881 μg/g dry weight. Titanium was somewhat mobile with considerable yield decrease at 10^‐4 M; leaf, stem, and root Ti concentrations, respectively, were 202, 48, and 2420 μg/g. Symptoms were chlorosis, necrotic spots on leaves, and stunting. Silver was very lethal at 10^‐4 M AgNO₃; at 10^‐5 M yields were greatly decreased, but plants were grown without symptoms. Leaf, stem, and root concentrations of Ag for this treatment, respectively, were 5.8, 5.1, and 1760 μg/g dry weight. Plants grown with 10^‐5 N Cr₂O₇ were decreased in yield by about 25% with or without EDTA (ethylenediamine tetraacetic acid) while the same level of Cr₂(SO₄)₃ was essentially without effect. For the two salts, the leaf, stem, root concentrations for Cr, respectively were 2.2 and 1.3, 0.7 and 0. 7, and 140 and 104 μg/g. Most of the trace metals studied here had interactions in the uptake and/or distribution of other elements.     

抗坏血酸钛对樱桃番茄产量和品质的影响

抗坏血酸钛在樱桃番茄上的试验于2006～2008年进行,发现对樱桃番茄叶面喷施抗坏血酸钛具有显著的提高产量和改善品质的作用。叶面喷施10～20 mg/kg的钛2次,对促进保护地、露地樱桃番茄早熟增产、优质及提高经济效益效果显著。抗坏血酸钛能促进樱桃番茄植株生理活性增强,提高过氧化氢酶活性,有利于樱桃番茄叶绿素含量增加和光合作用强度提高,果实中可溶性固形物和维生素C含量增加等。     

不同光源下TiO_2膜对MC-RR光催化降解的比较研究

通过溶胶-凝胶法制备了纳米级的锐钛矿型TiO2膜,利用纯化的MC-RR分别研究了该膜在太阳光、UVA和UVC三种光源下对MC-RR的催化降解行为。结果表明,太阳光下TiO2膜对MC-RR的催化降解反应符合一级反应动力学,而在UVA和UVC下符合二级反应。不同光源下TiO2膜的催化效果差别较大,在太阳光下催化效果最为明显,反应速率常数由5.12×10-5·min-1增加到5.49×10-3·min-1,增加了两个数量级;UVA次之,由6.0×10-4L·mg-1·min-1增加到1.55×10-3L·mg-1·min-1,增加了1.6倍;而在UVC下,反应速率常数由3.2×10-2L·mg-1·min-1减小到1.98×10-2L·mg-1·min-1,减小了近38%,说明在UVC下TiO2膜具有抑制作用。尽管如此,MC-RR在UVC下的反应仍然是最快的,光照60min后降解率达到90.7%,其次是UVA,60min后降解率为49.5%,而太阳光下仅为31.2%。在应用TiO2膜光催化氧化法去除MC的过程中,应综合考虑能耗、水质指标以及设备投资等因素,选择合适的光源,以免降低MC的去除效率或增加能耗。     

镍钛手用锉与不锈钢手用锉对弯曲根管成形能力的对比研究

目的 :对比镍钛手用锉 (NiTiFLEX)与不锈钢K型锉 ,K Flex锉预备塑料块中的弯曲管的成形能力。方法 :3 6个内含相似弯曲根管的塑料块分为 3组 :( 1)镍钛手用锉组 ;( 2 )不锈钢K Flex锉组 ;( 3 )不锈钢K型锉组。均以逐步后退法预备根管 ,叠加根管预备前后的扫描图像 ,分析根管弯曲部分的形态变化。结果 :( 1)组基本维持原根管曲线 ,根尖 1/3平均角度偏移为 ( 1.2 8°± 0 .73°) ,( 2 )组、( 3 )组根管直化较明显 ,根尖 1/3平均角度偏移分别为 ( 10 .76°± 1.17°)和 ( 12 .5 8°± 1.0 9°) ,与 ( 1)组比较差异有显著性 (P <0 .0 1) ,( 2 )组与 ( 3 )组比较差异亦有显著性 (P <0 .0 1)。根管轴心偏移在弯曲部分向内 ,在根尖区向外 ,偏移量 ( 1)组最小 ,( 2 )组次之 ,( 3 )组最大 ,( 1)组与另两组间差异有显著性 (P <0 .0 1) ;除根尖处外 ,( 2 )组较 ( 3 )组的偏移量差异亦存在显著性 (P <0 .0 1)。 ( 2 )组、( 3 )组预备后的根管较 ( 1)组显著增宽 ,两组间只在距根尖 4mm差异有显著性 (P <0 .0 5 ) ,且均有根尖拉开和肘部形成。 ( 1)组无根尖拉开及肘部形成。结论 :镍钛手用锉较不锈钢手用锉能保持原根管曲线 ,形成良好的根管形态     

喷钛对甜叶菊糖苷含量和积累量的影响

为探索喷钛对甜叶菊叶片中糖苷、甜菊苷(St)和莱鲍迪苷A(RA)的含量、积累量及其比例的影响,为中药材的施肥提供科学依据,应用盆钵培养方法,在甜叶菊生长前期和中期进行叶面喷钛。结果表明:菊隆5号的最佳喷施区间12.22~19.36 mg·kg-1,在喷钛浓度为19.36 mg·kg-1时含量达到最高;新品种2号的最佳喷施区间为12.10~16.71 mg·kg-1,在喷钛浓度为16.71 mg·kg-1时含量达到最高;喷钛后新品种2号St所占比例的最高增幅为156.71%,菊隆5号St的最高增幅为42.28%。喷钛可明显提高糖苷含量和积累总量,与对照相比,差异显著;经回归发现糖苷含量或积累量与喷钛浓度间存在二次曲线关系,相关极显著;喷钛可以增加2个品种糖苷中St的比例。