Average-bond-energy and Fermi Level on Free Electronic Band

【中文摘要】 根据半导体自由电子能带模型 ,文中在面心立方 (fcc)晶体、体心立方 (bcc)晶体和 6角密堆积 (hcp)晶体中研究自由电子能带的平均键能 Em 和费米能级 EF 的关系 ,并得出自由电子能带的平均键能 Em 相当于费米能级 EF 的研究结果。其结果有助于了解平均键能 Em 的物理实质 ,同时也为自由电子系统提供一种通过自由电子能带计算费米能级 EF(或费米半径 k F)的方法 【英文摘要】 Based on the free electronic band model, we study the relationship between average bond energy E m and Fermi level E F in face centered cubic (fcc) crystal, body centered cubic (bcc) crystal and hexagonal closed packed structure (hcp) crystal. It is concluded that the average bond energy E m is equivalent to the Fermi level E F on free electronic band. The results may help to understand the physical conception of average bond energy E m and also supply a method to calcu...高校博士点基金 (9538409); 福建省自然科学基金 (E990005)资助项

RESEARCH ON PRETREATMENT OF REFINERY ORGANIC ALKALI WASTEWATER WITH HIGH CONCENTRATION

经实验比较了UVO3、UVH2O2、UVTiO2H2O2系统对炼油高浓度废碱水的降解。结果表明,3种方法均有较好的效果,在本实验条件下,UVTiO2H2O2法的除油效果明显。在UVO3系统中,紫外光使废水CODCr、油、酚的降解率分别提高24%、31%、28%,特别是将废水BOD5CODCr值平均提高到0.45,有效地改善了废水的可生化性,因此是一种较好的预处理技术,同时该实验也为进一步的动态实验奠定基础。It is compared that the degradation of refinery organic alkali wastewater with high concentration by UV/O_3,UV/H_2O_2 and UV/TiO_2/H_2O_2 systems.The results show that three methods all have good degradation effect.On condition of the experiment, UV/TiO_2/H_2O_2 process has an obvious effect of oil removal.In the UV/O_3 system ultraviolet light makes the degradation rates of COD_ Cr,oil and phenol in the watewater increase by 24%,31% and 28% respectively,and particularly let the average of BOD/COD_ Cr raise by 0.45.Thus the biodegradability of the wastewater is improved effectively

聚羧酸系减水剂与萘系减水剂的性能比较

通过外加剂的匀质性试验、胶砂强度与收缩性能试验以及混凝土性能试验,对聚羧酸系减水剂与萘系减水剂的性能进行了对比。研究表明,与萘系减水剂相比,聚羧酸系减水剂在低掺量的条件下,不但有着更高的减水率,而且保塑能力强;所配制的胶砂及混凝土的强度增长显著,低收缩、体积稳定性好。该系列减水剂在厦门嵩屿2#泊位码头胸墙面层的混凝土工程中的应用取得了良好的效果。聚羧酸系减水剂特别适合高强混凝土、高性能混凝土、自密实混凝土、清水混凝土、大体积混凝土以及预制混凝土工程

整体式焦油裂解催化剂的制备及性能研究

以堇青石为载体，采用真空浸渍法制备整体式镍基催化剂，研究了不同干燥方法对整体式催化剂内表面活性组分轴向分布的影响及不同工艺条件下的催化性能。结果表明：微波干燥法所得催化剂内表面活性组分轴向分布最均匀；重时空速对焦油裂解率的影响较大，当重时空速为177kg／（h·m3）时，焦油裂解率高达92．62％，H2的体积分数为46．53％；在较低温度条件（700～800％）下，催化温度对焦油裂解的影响较小，当催化温度上升到900℃时，焦油裂解率大幅上升，单位质量生物质气体产率高达1．22Nm3／k

由杉木锯屑生物质制合成气:镍基整体式催化剂的表征及催化性能

以酸处理的蜂窝状堇青石为载体制得了一系列用于生物质热解气制合成气的不同NiO负载量的整体式催化剂,考察了该Ni基催化剂的催化性能.结果表明,酸处理后堇青石载体的比表面积和孔容分别可达156m2/g和0.099m3/g;NiO的负载使得比表面积和孔容急剧减小,并随着NiO负载量的增加而变化不大.NiO负载量对产气组分的影响很小,其中H2与CO的体积含量之和均为90%左右,焦油裂解率受催化剂比表面积的影响不明显.催化剂中NiO负载量为28%时,反应6h后,催化剂的物相结构能够基本保持稳定,反应产生的积炭量约为1%,产气率与焦油裂解率均有所下降,其中焦油裂解率由87.4%下降为81.3%

Study on Equipment and Process in Injection/Falloff Test in Coalbed

较为全面地介绍了煤层气注入/压降方法的基本原理、测试方法、测试设备、测试过程、测试数据分析以及注入压降测试的优缺点;分析了煤层气井在注入/压降设计、设备以及测试资料分析等方面存在的问题,提出了相应的改进及发展方向

APPLLICATIONS OF AVERAGE-BOND-ENERGY METHOD IN STRAINED\|LAYER HETEROJUNCTION BAND OFFSET

将平均键能方法推广应用于应变层异质结的带阶研究 .通过流体静压力应变和单轴应变对带阶参量Emv作用的仔细研究 ,发现平均带阶参量Emv,av=Em-Ev ,av在不同应变状态下基本上保持不变 .因此 ,在应变层带阶参量Emv的计算中 ,只需计算其发生应变前体材料的带阶参量Emv,o值并引用形变势b和SO裂距Δ0 的实验值 ,通过简便的代数运算得到应变层的Emv值 ,从而方便地预言不同应变层异质结的带阶 .该简化计算方案计算量小 ,并更直接地引用材料实验参量值以提高计算结果的可信度We have extended the average\|bond\|energy method to the study of strained\|layer heterojunction band offset. Through a careful study of the effect of hydrostatic strain and uniaxial strain on band offset parameter \%E\%\-\{mv\}, we find that the average band offset parameter \%E\%\-\{mv,av\}(\%E\%\-\{mv,av\}=\%E\%\-\{m\}-\%E\%\-\{v,av\}) is largely kept unchanged under different strain conditions. So, in the calculation of strained\|layer band offset parameter \%E\%\-\{mv\}, it is only required the unstrained band offset parameter \%E\%\-\{mv,0\}, a deformation parameter \%b\% and the experimental value of spin\|orbit splitting \%Δ\%\-0 to calculate the value of strained\|layer \%E\%\-\{mv\} by simple algebraic operation. Obviously, it will be very convenient to calculate the valence band offset of heterojunction. The simplifed calculation scheme has the characteristic of small calculation amount and the calculation reliability can be improved by using the experimental value.高等学校博士学科点专项科研基金!(批准号:953840 );; 福建省自然科学基金!(批准号:E990005)资助的课

Deformation Potentials of GaN and AlN, and Band offsets at GaN/AlN Heterojunction

本文采用混合基矢从头赝势能带计算方法研究了（001）界面应变对gAn、Aln应变层的能带、平均键能EM和带阶参数EMV的影响.借助于带阶参数形变势的计算，预言了不同生长厚度情况下gAn/Aln应变层异质结价带带阶和导带带阶.Abstract The effect of strain along orientation on band structure of Zinc blende GaN and AlN, average bond energy E m, and band offset parameters E mv are investigated by the ab initio mixed basis pseudopotentials.When obtaining the deformation potential of E mv for GaN and AlN, the band offsets of strained layer heterojunction GaN/AlN under different growth thicknesses can be predicted.国家自然科学基金;高校博士点专项科研基

Fermi Level Calculation by Free Electronic Band Model

对面心立方 (fcc)、体心立方 (bcc)和六角密堆积 (hcp)三种不同结构的晶体 ,在假设它们的原胞中包含8个价电子并将价电子近似为自由电子的情况下 ,采用“自由电子气理论”和“自由电子能带模型” ,研究其根据费米球确定的费米能级EF 与根据自由电子能带模型计算的平均键能Em。研究结果表明 ,由自由电子能带模型计算所得 3种不同结构晶体 (因而电子密度也不一样 )的平均键能Em 等于各自自由电子系统的费米能级EF。平均键能Em 是我们在异质结带阶理论计算中建议的一种参考能级 ,研究结果在深化对平均键能Em 物理实质认识的同时 ,提供了一种借助于自由电子能带模型计算自由电子系统费米能级EF 的新方法。Three different kinds of crystal structures,face centered cubic(fcc),body centered cubic(bcc),and hexagonal close packed(hcp) structures with eight valence electrons in each primitive unit cell were studied.In the framework of free electron approximation,their Fermi level E F were determined by Fermi sphere according to the theory of free electron gas,and the average bond energies E m were calculated by free electronic band model.The calculated results of E F and E m indicate that the average bond energies E m of three different crystal structures (therefore their electron densities are different) correspond to their Fermi levels E F respectively.In the semiconductor energy band,the average bond energy E m is defined as the mid point of the energy gap between E b (bonding orbital energy) which is the avergage valence band level of the four highest valence band levels,and E a (anti bonding orbital energy) which is the average conduction band level of the five lowest conduction band levels in the whole Brillouin zone eigenvalues.It is the reference energy level in our theoretical calculation of heterojunction band offset.Therefore,the relationship between E F and E m found here is helpful to understand the physical concept of average bond energy E m and the reason why it aligns at the two sides of the heterojunction interface.It also suggests a new method to calculate the Fermi level E F of free electron systems through free electronic band model.高校博士点基金 ( 95 3 840 9) ;; 福建省自然科学基金 (E990 0 0 5 )资助项