团簇NiMo3P催化析氢性能的研究

为探究团簇NiMo₃P各优化构型的催化析氢性能,基于密度泛函理论,在B3LYP泛函的条件下,采用Lanl2dz基组对团簇NiMo₃P进行优化计算后,得到6种优化构型.对前线轨道图及各构型的HOMO轨道与水分子LUMO轨道间的能级差值进行分析发现:团簇NiMo₃P的6种优化构型均具有良好的催化析氢性能;在吸附氢原子时,团簇NiMo₃P各构型的β-HOMO轨道更具优势,且氢原子均吸附在团簇NiMo₃P的Mo原子上,即Mo原子为团簇NiMo₃P潜在的催化活性位点;在进行解吸反应时,构型3⁽(4))通过电化学解吸与化学重组两种方法析氢均具有良好的催化反应活性.     

基于量子化学的团簇Co4P非晶态合金析氢反应研究

为寻找在团簇Co₄P中具有最优催化析氢性能的构型,该文根据密度泛函理论于B3LYP/lanl2dz水平下对团簇Co₄P分别进行在二、四重态下的计算,根据前线轨道理论对优化后团簇Co₄P的HOMO图、水分子的LUMO图以及能级差进行分析,发现构型1⁽²⁾、2⁽²⁾的β电子与构型1⁽⁴⁾、2⁽⁴⁾的α电子的HOMO负相位对催化析氢反应的第1步提供了较大的贡献.此外,综合分析析氢反应的各步骤发现:构型2⁽²⁾具有较好的吸附能力,且该构型在吸附1个氢原子后在电化学解吸和化学重组解吸中均具有最优解析性质.因此,构型2⁽²⁾是在团簇Co₄P各优化构型中最优的催化析氢构型.     

两相流流动瞬变的计算方法及实验研究

从气液、固液、固气两相流的基本方程着手,利用特性曲线法对流体的流动瞬变推导出计算公式并不需对两相流作均匀分布的假设,经气液两相流的瞬变流的理论计算与实验验证,证明该方法是能满足工程精度要求的．     

类卡宾CBr3Li的构型及其异构化的理论研究

用密度泛函理论，对类卡宾CBr3Li进行了研究。优化得到4种不同的平衡构型及其相互转化的过渡态，并对过渡态进行了振动分析，确认它们均只有惟一的虚振动模式。分析了各构型的特点，给出偶极矩、电荷分布和前线分子轨道能，并对该类卡宾的化学性质进行了讨论。     

营养对C3H／He小鼠生长繁殖功能的影响

探讨营养与环境因素对C3H／He小鼠繁殖功能的影响。观察不同营养与环境条件对C3H／He小鼠初配产仔率、离乳仔数、体重增长等生殖、生长特性，并与昆明小鼠比较。表明C3H／He小鼠一年四季均具有繁殖能力，C3H／He最长妊娠24d，最短19d，平均20.9d，平均窝产仔数4.2只，较昆明小鼠有更短和更不规则的动情周期，营养、环境因素等影响其繁殖行为。     

相场中场变量参数对二维晶粒演变特征影响的研究

采用了周期性边界条件及各向同性的动力学相场模型研究了场变量参数对二维多晶生长的影响.模拟结果表明:场变量数目的多少对晶粒生长的规律没有显著影响:即二次幂规律,场变量数目越大,晶粒合并的几率越小,生长越慢.同时又对不同场变量下晶粒的相对尺寸分布进行了研究,结果显示晶粒的相对尺寸分布形式具有相似性.     

滑动摩擦下氮化硼与几种常用固体润滑剂添加效果的比较

将氮化硼以及常用二硫化钼，石墨，氟化石墨粉末分散添加入润滑油和润滑脂中，加至滑动摩擦副表面进行摩擦，磨损比较试验，结果表明：氮化硼添加具有良好的减摩，降磨效果，值得引起重视。     

氢原子n=4能级的斯塔克效应

讨论了氢原子n=4能级的斯塔克效应,能量修正至一级近似。     

THE EFFECT OF TRANSITION METAL IONS-IRON ON HYDROGEN PEROXIDE BLEACHING

INTRODUCTIONHydrogen peroxide bleaching has been extensively used in high-yield pulp bleaching. IT is well known that hydrogen peroxide can be easily decomposed under alkaline conditions, especially in the presence of transition metal ions due to their catalyzing effect on the decomposition of hydrogen peroxide. Some recent reports show that the valence of transition metal ion can have a drastic effect on the decomposition of hydrogen peroxide.Generally, iron can exist in Fe2+ and Fe3+…     

THE EFFECT OF TRANSITION METAL IONS-MANGANESE ON HYDROGEN PEROXIDE BLEACHING

INTRODUCTIONHydrogen peroxide bleaching has been extensively used in high-yield pulp bleaching. It is well known that hydrogen peroxide can be decomposed under alkaline conditions, especially when transition metal ions are present. Recent studies showed that valence of transition metal ions is a significant factor in these reactions.Among various transition metal ions, manganese ions are the most harmful species during alkaline peroxide bleaching. Manganese has seven valence electrons (3d…     

HE EFFECT OF TRANSITION METAL IONS-IRON ON HYDROGEN PEROXIDE BLEACHING

Hydrogen peroxide bleaching has been extensively used in high-yield pulp bleaching. Unfortunately,hydrogen peroxide can be decomposed under alkaline condition, especially when transition metal ions exit. Experiments show that the valence of transition metal ion is also responsible for the decomposition of hydrogen peroxide.Iron ions are present in two oxidation states, Fe2+ and Fe3+. They are both catalytically active to hydrogen peroxide decomposition. Because Fe3+ is brown, it can affect the brightness of pulp directly, it can also combine with phenol, forming complexes which not only are stable structures and are difficult to be removed from pulp, but also significantly affect the brightness of pulp because of their color.Sodium silicate and magnesium sulfate, when used together, can greatly decrease hydrogen peroxide decomposition. The optimum dosage of sodium silicate is about 0.1% (on solution) for Fe2+ and 0.25% (on solution) for Fe3+. Adding chelants such as DTPA or EDTA with stabilizers simultaneously can obviously improve pulp brightness. For iron ions, the chelate effect of DTPA is better than that of EDTA.Under acidic conditions, sodium hyposulfite and cellulose can reduce Fe3+ to Fe2+ effectively, and pulp brightness is improved greatly. Adding sodium thiosulfate simultaneously with magnesium sulfate,sodium silicate, and DTPA to alkaline peroxide solution can result in higher brightness of pulp.pH is a key parameter during hydrogen peroxide bleaching, the optimum pH value should be 10.5-12.     

顺式聚乙炔衍生物取代基效应的理论研究

用自洽场晶体轨道法(SCF-CO)讨论了顺式聚乙炔取代衍生物的取代基效应。研究表明,这些取代衍生物仍存在带隔。吸电子基团(-CN,-F)的取代使体系的电子亲合势和电离势增大,而给电子基团(-CH_3,-NH_2)的取代,则使体系的电离势降低。     

空气中二氧化碳对常规分析岩石有机碳含量的影响

岩石中有机碳含量是研究生油岩的重要基础指标,它的准确程度直接影响其它地化指标及生油指标的准确程度,影响对油气资源的评价。本文对分析有机碳的干烧氧化重量法的有关步骤进行了实验研究。研究表明,空气中的二氧化碳对岩石样品中的有机碳含量有很大影响。样品在空气中放置的时间越长,有机碳的含量就越高。而把样品放入干燥器内密封存放,所测有机碳含量比较稳定,可为油气资源评价提供可靠依据。     

纳米凹凸棒土对碳纤维/BMI树脂复合材料的增强与增韧

采用预浸料模压工艺制备了纳米凹凸棒土／短碳纤维／ＢＭＩ树脂复合材料。实验并分析了纳米凹凸棒土对复合材料的增强与增韧作用,当其质量百分比为５％～６％时,弯曲强度和冲击强度分别提高了３０％和５７％。     

氢键作用对POM／COPA共混物结构与性能的影响

本文采用ＦＴ－ＩＲ、ＤＳＣ、ＳＥＭ、ＷＡＸＤ等手段对ＰＯＭ／ＣＯＰＡ共混物的微观结构进行分析，并且对其力学性能进行测试．研究结果表明，在ＰＯＭ／ＣＯＰＡ共混物中存在着氢键的相互作用，且氢键的相对强度随ＣＯＰＡ含量的增加而增大，氢键作用使得微晶尺寸Ｌ_（１１０）及晶胞尺寸均增大．在氢键的相对强度低于１．５的范围内，ＣＯＰＡ对ＰＯＭ具有增韧改性作用．