Cu 电化学溶解与阻蚀的交流阻抗研究液／液界面离子传输的促进与抑制

1. 对恒定电位下，不同浓度的 Cl~- 介质中 Cu 的电化学溶解行为用交流阻抗方法进行了充分表征，通过对这些阻抗图谱的解析处理，结合扫描显微镜（SEM）照片，提出了 Cu 的溶解机理。所得结果与文献用其他方法一致。2. H_2SO_4 介质中，测得不同浓度，不同电位下 Cu 的电化学溶解过程的交流阻抗图谱，对所得各种情形下的图谱进行了详细解析，提出了溶解的机理。3. KCl 介质中，还探讨了异硫氰酸苯酯（C_6H_5NCS）的吸附对 Cu 电化学溶解行为的影响，获得了阻蚀行为的特征阻抗图谱。4. 分析阻抗 Bode 图时，发现表面膜或覆盖层的存在与电容和阻抗 Bode 图上的突跃有一定的关联。文献尚未见这方面的有关报道。

TRBC受体不同于已知T淋巴细胞粘附分子

人和猕猴T淋巴细胞能与树鼠句红细胞(tree shrew red blood cell, TRBC)形成结合力特强的玟瑰花结（T－花结），这种花结有与E－花结不同的物理和化学特性（贲昆龙 等，1985）。T细胞表面的这种TRBC受体及其配体不同与CD2、E2分子及其配体(Ben and Zheng, 1991)。为了进一步探讨TRBC受体与已知粘附分子的关系，我们用抗CD2、CD11a、D29、CD44、CD56、E2和CAM'S的单抗，用抗原调变、花结形成的阻断等试验研究了TRBC受体与这些分子的关系。继而选择了既能调变E－受体又能调变TRBC受体的六种单抗，以免疫转印技术，比较了NP－40，毛地黄皂苷，超声和高渗KCL四种方法装取的膜抗原中CD2和TRBC受体的特性。

铵、钾在几种土壤中的固定及铵、钾关系

本文主要研究了实验室条件下NH_4~+和K~+在五种土壤中被矿物质固定的程度及固定过程中的铵、钾关系。0～30天的观测结果表明：83～100％的铵、钾固定发生在2天内，其中铵的固定速度大于钾。在含水量为最大持水量的50％时；施入14.29μMNH_4~+／g烘干土被固定25.0～83.3%，施入同量K~+被固定28.0～67.9%。在固定过程中，铵与钾主要是相互竞争的关系，即双方竞争同一固定位置。在同等条件下，NH_4~+ 的竞争能力比K~+ 强。NH_4~+ 的存在常常妨碍K~+的固定，而K~+的存在往往促进NH_4~+的固定（先施K~+时除外）。将三种2:1型自然土壤中铵、钾固定量与其原有的固定态铵、钾量进行相关分析，初步证明：施入NH_4~+、K~+的固定量与原有的固定态铵、钾量呈极显著的正相关关系，同时也得出：不同矿物对NH_4~+、K~+的“选择性”不同，蛭石对K~+的“选择性”强，而水云母对NH_4~+的“选择性”强。此外，在予备试验中，还对固定态铵的分析测定方法进行了研究与比较，并提出了一种测定固定态铵的新方法－H_2SO_4法。将H_2SO_4法与HF法同时用于12种不同土壤中原有固定态铵的测定。得出：H_2SO_4法测定值显著高于HF法。其原因可能是H_2SO_4法测出了非硅酸盐矿物所固定的铵（用“R-NH_4”表示)，“R-NH_4”在 2:1 型土壤中占全N的0～9.5%。将H_2SO_4法、HF法和 KCl法同时用于观测四种土壤对施入NH_4~+ 的固定。结果表明：三种方法测得的变化趋势大致相同，但测定值高低不同： KCl 法＞HF法≈H_2SO_4法。将三种方法所得结果进行比较研究后，初步证明：(1). "R-NH_4" 在土壤中也存在“固定”与“释放”作用；(2). “NH_4/K”处理所固定的铵比其它处理固定得更牢固。

一株丝状真菌对半纤维素利用的初步研究

本文筛选出一株能利用木糖产乙醇的丝状真菌Z7，对其利用木糖和半纤维素水解产物产乙醇的发酵条件进行了研究，并对Z7 利用玉米芯产木聚糖酶的条件进行了优化。全文分为三部分： 第一部分：目标微生物筛选、纯化及系统发育分析。以木糖为唯一碳源，采用梯度稀释和平板化线法从高温、中温酒曲中分离到16 株能利用木糖良好生长的丝状真菌；通过发酵试验复筛，获得一株能产乙醇的丝状真菌Z7；综合形态学和ITS 序列分析，初步鉴定为Aspergillus flavus。 第二部分：Z7 的乙醇发酵条件研究。以木糖为碳源，通过单因素试验确定最佳氮源和发酵温度；通过正交试验及SPSS 软件分析得到了不同N、P、K 成分对乙醇、残糖和菌体干重的影响。获得最佳的发酵条件为：（g/L）木糖50，尿素1, NH4NO3 1, K2HPO4 2 , KCl 0.5 , MgSO4.7H2O 0.5 , NaNO3 1 , pH 自然，培养温度33 ℃。以玉米芯半纤维素稀酸水解液为底物进行乙醇发酵，根据稀酸水解的单糖释放量和乙醇产量，确定115 ℃，1 h 为最佳玉米芯预处理条件；结合最佳发酵条件，添加1 g/L 的吐温20 能获得最大的乙醇浓度8.31 g/L。因此，Aspergillus flavus Z7 能利用半纤维素水解产物产乙醇，其中木糖的利用率80%以上。 第三部分：Z7 利用玉米芯产木聚糖酶条件优化。Aspergillus flavus Z7 在具有产乙醇能力的同时还具有产木聚糖酶的能力。本文通过单因素和正交试验得到最佳产酶培养基组分为：(g/L)玉米芯20，尿素2, 酵母膏2.5, K2HPO4 5，NaNO31, MgSO4.7H2O 1。单因素试验表明，用纱布代替塑料布密封摇瓶封口能显著提高产酶量；Z7 在碱性条件下具有更强的产酶性能。在最优条件下发酵，能产生最大木聚糖酶活122.23IU/mL。通过薄层分析，验证了Z7 产生的木聚糖酶具有水解木聚糖生成木糖及木寡糖的能力。 A strain of filamentous fungus which can produce ethanol by using the xylose was isolated in this research. The ethanol fermention conditions from xylose and dilute-acid hydrolyzate of the corn core were studied. The conditions of xylanase production by Z7 were also optimized. The paper involved three parts. Part1: Isolation, purification and phylogenetic analysis of the microbe. By using xylose as the single carbon source and the pla te streaking method, several filamentous fungi were isolated from the wine starter; through the fermentation test, a filamentous fungus Z7 which can produce ethanol was further recognized; furthermore, according to the morphologic observation and ITS seque nces analysis, Z7 was identified as Aspergillus flavus at the first step. Part2: Research on the condition of ethanol fermentation by Z7. By single factor experiment, the optional nitrogen resource and temperature of the fermentation were fixed; meanwhile, through the orthogonal array tests and the analysis of statistic software SPSS, the optional component of the culture medium and the fermentation condition were organized as follows: (g/L) xylose 50, urea 1, NH4NO3 1, K2HPO4 2, KCl 0.5 , MgSO4.7H2O 0.5, NaNO31, pH nature, temperature 33℃. Based on these optimal parameters, the fermentation of dilute-acid hydrolyzate of the corn core was carried on by Z7. According to the quantities of released sugar monomers and content of the ethanol, 115℃ in 1h is the best pretreatment condition; the maximal ethanol content can be obtained when 1g/L Tween 20 was added to. Therefore, the filamentous fungus Aspergillus flavus can use the hydrolysate of hemicellulose to produce ethanol, and the rate of xylose utilization was over 80%. Part3: Optimization of Z7’s xylanase producing condition from corn core. Aspergillus flavus Z7, which can utilize xylose or the hydrolysate of hemicellulose to produce ethanol, also had the ability of xylanase production. The optional component of the culture medium were fixed by the single factor experiment and the orthogonal array tests, and they were organized as follows: (g/L) corn core 20, Urea 2, Yeast extract 2.5, K2HPO4 5, NaNO31, MgSO4.7H2O 1; it was testified by the single factor experiment that sealing the shaking flasks with pledget other than plastic paper can obviously increase the xylanase activity; moreover, Z7 showed better xylanase production ability when in the alkali environment. Under the optional fermentation condition, the maximal xylanase activity 122.23IU/mL was proved. Through the analysis of thin- layer chromatography (TLC), the ability of xylanase from Z7, which can hydrolyze xylan to xylose monomer and oligomer, was vividly displayed.

产纤维素酶原生质体形成和再生条件选择

研究了4种营养缺陷型产纤维素酶菌的原生质体形成和再生条件。结果表明 ,它们原生质体形成条件均以0.2mol·L-1(pH5.8)磷酸缓冲液为好。绿色木霉(Trichodermaviride)UV2 -11 和另一未定木霉(T.sp.)UV2 -2 以0.7mol·L-1KCl的渗透稳定剂为好 ,菌丝菌龄分别为20,18～20h ;康宁木霉(T.Koningii)UV2 -1 和UV2 -15 以0.6mol·L -1NaCl的渗透稳定剂为好 ,菌丝菌龄均为16～20h,酶解时间均为2～3h。原生质体再生培养基以加入0.5%酵母膏和0.5 %泛酸钙的改良Czapek培养基效果好 ,用0.7mol·L-1 KCl和NaCl作为渗透稳定剂 ,菌株原生质体的再生率较高

氮肥和钾肥强化龙葵修复镉污染土壤

采用室外盆栽实验,研究了施用氮肥[(NH4)2SO4]和钾肥(KCl)对镉超积累植物龙葵(Solanum nigrumL.)的生长和吸收累积Cd的影响.结果表明,(NH4)2SO4虽不能显著提高龙葵地上部Cd含量,但可显著提高龙葵地上部干重,因而显著提高了龙葵地上部Cd的积累量,最大可提高2.8倍;KCl在高浓度处理时可以显著提高龙葵地上部Cd含量,然而它对地上部干重有抑制作用,最终没能提高龙葵地上部Cd的积累量.施用(NH4)2SO4可显著降低土壤pH值,但对土壤有效态Cd含量无显著影响;施用KCl可使土壤pH值显著提高,同时使土壤有效态Cd含量显著增加.(NH4)2SO4的强化龙葵修复效果较好.

缓释尿素中硝化抑制剂DMPP的气相色谱法测定

建立了一种检测缓释尿素中吡唑类硝化抑制剂DMPP的气相色谱法。DMPP在尿素水溶液中可定量转化为DMP,从5种有机溶剂中选择氯仿作为DMP的萃取剂,并采用加入KCl盐析的方法将萃取率从96.1%提高到99.5%。本文采用吡啶作为内标物,通过DB-1701气相色谱柱,氢火焰离子化检测器(FID)定量检测氯仿溶液萃取相中的DMP。萃取率为98.8%~100.4%;添加回收率为98.1%~99.5%;RSD为0.84%~1.6%。应用本法测定自制缓释尿素中DMPP质量分数为0.44%。

石灰性土壤供氮能力几种化学测定方法的评价研究

以采自于黄土高原差异较大的25个农田耕层石灰性土壤为供试土样,以淋洗和未淋洗土壤起始NO3--N小麦和玉米两季盆栽试验作物累积吸氮量为参比,对8种反映旱地土壤供氮能力的化学方法进行比较研究。结果表明,在一定程度上,可用有密切关系的土壤全氮或有机质,反映有机氮或全氮存在较大差异的土壤供氮能力,但其灵敏性较差。石灰性土壤矿质氮,特别是NO3--N与未淋洗土壤起始NO3--N作物吸氮量之间有较高相关性(r=0.884,P<0.01),而与淋洗土壤起始NO3--N作物吸氮量间相关系数仅为0.472(P<0.05),说明矿质氮可反映土壤当前供氮水平,而不能反映土壤潜在供氮能力;石灰性土壤起始NO3--N对各化学方法与作物吸氮量之间相关性影响较大。酸性高锰酸钾法既可反映土壤潜在供氮能力,也可反映土壤总供氮能力;酸性高锰酸钾法的修订方法,即硫酸—高锰酸钾法提取出的NH4+-N值接近于KCl水浴法提取出的NH4+-N值,该方法在反映土壤总供氮能力方面与酸性高锰酸钾法相当,但在反映土壤潜在供氮能力方面不及酸性高锰酸钾法优越。KCl水浴法在评价石灰性土壤供氮能力方面,与酸性高锰酸钾法的效果基本相同;沸水浸取法和NaHCO3-UV...

模拟酸雨对果园土壤主要形态酸变化的影响研究

采用室内淋溶的方法研究了模拟酸雨对果园土壤pH(H2O)、pH(KCl)、交换性酸(EA)、交换性铝(EAl)、可滴定酸度(BNC)等各形态酸的变化影响,并依据淋溶前后各形态酸的含量评价了土壤酸度的变化。试验结果表明:以土壤pH(H2O)值作为供试土壤酸化指标,pH≤4.5的模拟酸雨淋溶促进了土壤酸化,而pH≥5.5的酸雨淋溶缓冲了土壤的酸化;以土壤pH(KCl)值、交换性酸(EA)、交换性铝(EAl)或可滴定酸度(BNC)作为土壤酸化的指标,pH2.5的酸雨淋溶促进了土壤酸化,而pH≥3.5的淋溶处理缓冲了土壤的酸化,土壤酸度减弱。

C-60 trianion-mediated electrocatalysis and amperometric sensing of hydrogen peroxide

Heterogeneous electrocatalytic reduction of hydrogen peroxide (H2O2) by C-60 is reported for the first time. C-60 is embedded in tetra octyl ammonium bromide (TOAB) film and is characterized by scanning electron microscopy and cyclic voltammetry. Electrocatalytic studies show that the trianion of C-60 mediates the electrocatalytic reduction of H2O2 in aqueous solution containing 0.1 M KCl. Application of such film modified electrode as an amperometric sensor for H2O2 determination is also examined.

F-肌动蛋白与负电荷磷脂膜的相互作用研究

细胞膜的内膜含有大量的负电荷磷脂,研究F2肌动蛋白与负电荷磷脂的相互作用将有助于更深入 地了解细胞骨架与细胞膜的体内相互作用机制。在金片和金电极上分别构建了负电荷磷脂的杂化双层磷脂 膜,通过表面等离子体共振方法( SPR)和电化学阻抗技术研究了F2肌动蛋白与负电荷磷脂膜的相互作用。结 果表明, F2肌动蛋白可以在没有中间联系蛋白的情况下,直接与负电荷磷脂膜发生相互作用。钙离子可以有 效地促进它们的相互作用,表明钙离子在其中发挥了重要作用。高浓度的KCl显著抑制它们的相互作用,表 明这种相互作用主要受静电作用影响。实验结果进一步证明在F2肌动蛋白与负电荷磷脂膜相互作用时,除 了可以通过其它蛋白发生间接相互作用外,还可以与磷脂膜发生直接的相互作用。

Crystalline organic superlattice

Highly crystalline organic superlattice has great potential for providing innovative function in organic devices. With studies of the structure and fundamental electronical properties, we have demonstrated the phathalocynine organic superlattice, which is a structure composed of periodically alternating crystalline layers of H2Pc and F16CuPc. A periodical crystal structure and electronic structure appear in this organic superlattice system. High density of mobile electrons and holes distribute periodically in F16CuPc and H2Pc layers, respectively, leading to a significant change in intrinsic properties of organic semiconductors.

Electrolytic Deposition and Diffusion of Lithium onto Magnesium-9 Wt Pct Yttrium Bulk Alloy in Low-Temperature Molten Salt of Lithium Chloride and Potassium Chloride

The electrolytic deposition and diffusion of lithium onto bulk magnesium-9 wt pct yttrium alloy cathode in molten salt of 47 wt pct lithium chloride and 53 wt pct potassium chloride at 693 K were investigated. Results show that magnesium-yttrium-lithium ternary alloys are formed on the surface of the cathodes, and a penetration depth of 642 mu m is acquired after 2 hours of electrolysis at the cathodic current density of 0.06 A center dot cm(-2). The diffusion of lithium results in a great amount of precipitates in the lithium containing layer. These precipitates are the compound of Mg41Y5, which arrange along the grain boundaries and hinder the diffusion of lithium, and solid solution of yttrium in magnesium. The grain boundaries and the twins of the magnesium-9 wt pct yttrium substrate also have negative effects on the diffusion of lithium.

Prussian Blue/Multiwalled Carbon Nanotube Hybrids: Synthesis, Assembly and Electrochemical Behavior

Prussian blue/carbon nanotube (PB/CNT) hybrids with excellent dispersibility in aqueous solutions were synthesized by adding CNTs to an acidic solution of Fe3+, [Fe(CN)(6)](3-) and KCl. Fourier transform infrared spectroscopy, UV-vis absorption spectroscopy and scanning electron microscopy were employed to confirm the formation of PB/CNT hybrids. The PB nanoparticles formed on the CNT surfaces exhibit a narrow size distribution and an average size of 40 nm. The present results demonstrate that the selective reduction of Fe3+ to Fe2+ by CNTs is the key step for PB/CNT hybrid formation. The subsequent fabrication of the PB/CNT hybrid films was achieved by layer-by-layer technique. The thus-prepared PB/CNT hybrid films exhibit electrocatalytic activity towards H2O2 reduction.

Application of Ru(bpy)(3)(2+) in control and formation of gold surface nanostructure through oxidation-reduction cycling

It was studied that the nanostructure formed on a gold surface via a simple oxidation-reduction cycles (ORC) in 0.1 M KCl containing Ru(bpy)(3)(2+) with different concentrations. Atomic force microscopy (AFM) and energy-dispersed spectroscopy (EDS) were used to characterize the nanostructure formed on the gold surface. Sweep-step voltammetry and corresponding electroluminescence (ECL) response, in situ electrochemical quartz crystal microbalance (EQCM) measurement were used to monitor the ORC. procedure. It was found that the surface structure became more uniform in the presence of Ru(bpy)(3)(2+), and the surface roughness was decreasing with the increasing of Ru(bpY)(3)(2+) concentration, suggesting a simple and effective method to control the formation of nanostructure on the gold surface.