The influence of different calculation methods and basis sets of Au on the calculation results were also discussed systematically.
对计算结果分析表明，不同计算方法对Au配合物结构和二阶NLO系数影响较大，其中用考虑电子相关效应的DFT-B3LYP和MP2方法优化得到的Au—P配键长比用HF方法的短，相应的二阶NLO系数比HF方法的大2倍左右；同一计算方法下，Au基组中 d 轨道个数增加优化得到的Au—P配键键长减小；随着Au基组的增大，前线分子轨道能级差减小，其中SDD和CEP-121G基组之间的变化更明显。
By applying Sutherland potential to this model, the new attractive term above is derived. By applying Lennard-Jones potential to this model, it is found that Lennard-Jones potential, which is widely used as the pair-wise interaction in DFT theory and IEM, maybe not a good potential function. Then polynomial potential function is applied to this model.
该模型应用到Sutherland势函数中，得到上面的吸引项；该模型应用到Lennard-Jones势函数中得到的新结果对IEM的理论研究和DFT的理论研究有很好的启示性作用，指出，在DFT理论和IEM中广泛引用的Lennard-Jones势可能不是描述两粒子相互作用的最好的势函数。
The geometry and electronic structure in C62 and its four pyridinyl derivatives were calculated with DFT method at BP86/TZP level. With the time-dependent density functional theory method, we can assign the lowest excitation transitions and model absorption spectra.
采用密度泛函理论方法，在TZP基组水平下计算C62及其吡啶衍生物几何与电子结构，在全优化构型基础上，采用TD-DFT方法对其低激发态进行计算，预测其电子吸收光谱。
Density Functional Theory method was used to optimize the geometries of 209 PCDE molecules, 209 PBDE molecules and 75 PCDD molecules at the B3LYP/6-31G* level. Using computed structural parameters as theoretical descriptors, the forward stepwise multiple regression technique was adopted to obtain QSPR models of environmental partition properties for these POPs by using GQSARF 2.0 and SPSS12.0 for windows programs. The obtained QSPR models are as follows:(1) QSPR models for predicting subcooled liquid vapor pressure, n-octanol/water partition coefficients lgK_(ow and subcooled liquid water solubilities -lgS_(w, l of PCDEs, of which correlative coefficients (R~2) are 0.988, 0.958 and 0.959 and the root-mean-square-error of estimation are 0.134, 0.116 and 0.327 respectively.(2) QSPR models of lgPL and n-octanol/air partition coefficients lgK_(oa for PBDEs, which both contain three structural parameters. The values of R2 for the two models are both 0.997 while the values of RMSEE are 0.073 and 0.062 respectively.(3) QSPR models of lgKow and–lgS_ for PCDEs, which both have one variable (mean molecular polarizability, α). The values of R~2 for the two models are 0.978 and 0.866 and the values of RMSEE are 0.300 and 0.270 respectively.(4) The molecular structures of 24 substituted naphthaline compounds were optimized using Hartree-Fock and DFT methods at four different levels and the same means was used to obtain four three-parameter (EHOMO, q~+ andα) QSPR models of lgK_. The model at the HF/6-311G** level is the best one of which R2 is 0.9662 and RMSEE is 0.380.(5) QSPR study for environmental partition properties of PCDEs was also performed using position of Cl substitution method in which simple parameters of substitution position were taken as descriptors. The multiple linear regression was performed with GQSARF 2.0 and SSPS 12.0 for windows programs to obtain QSPR models of lgP_L, lgK_ and–lgS_ for PCDEs of which R~2 are 0.991, 0.983 and 0.965 and RMSEE are 0.311, 0.100 and 0.300 respectively.
采用密度泛函理论方法在B3LYP/6-31G*水平上对PCDEs、PBDEs和PCDDs的分子结构进行了全优化计算，以计算得到的量子化学参数作为理论描述符，采用GQSARF 2.0和SPSS 12.0 for windows统计程序进行正向逐步回归分析，建立了这些POPs的环境分配性质的QSPR模型：(1) PCDEs的过冷液体蒸汽压、正辛醇/水分配系数lgK_(ow和水溶解度-lgS_(w，l的QSPR模型，这3个QSPR模型的相关系数(R2)分别为0.988、0.958和0.959，估计的均方根误差分别为0.134、0.116和0.327；(2) PBDEs的lgPL和正辛醇/空气分配系数lgK_(oa的QSPR模型，这两个模型都包含三个分子结构参数，其R~2都为0.997，RSMEE分别为0.073和0.062；(3) PCDDs类化合物的lgK_和-lgS_w的QSPR模型，两个模型都只含一个变量，其R~2分别为0.978和0.866，RSMEE分别为0.300和0.270；(4)采用Hartree-Fock和DFT方法，在4种不同水平上优化计算了24个取代萘系列化合物的分子结构，采用上述同样的方法分别建立了四种水平上的三变量lgK_模型，通过比较得到，在HF/6-311G**水平计算得到的模型最好，R为0.966，RSMEE为0.380；(5)同时，采用氯原子取代位置方法对PCDEs的环境分配性质进行QSPR研究，建立了PCDEs的lgPL、lgK_和-lgS_的QSPR模型，其R~2分别为0.991、0.983和0.965，RSMEE分别为0.110、0.100和0.300。
In addition, extensions of DFT to the time dependent case and relativistic limit are also active topics.
除了交换相关近似的发展，近年来密度泛函理论向含时理论、相对论等方面的扩展也很活跃。
At first, setting up the arith relation between the signal input and the signal output of the generalized multi-carrier system of the Discrete Fourier Test spread-spectrum; then setting equilibria parameters of the frequency field equilibria subcarrier of the generalized multi-carrier system of the DFT spread-spectrum according to channel frequency response, channel noise variance and equilibria method; then calculating average power of useful signal, interferential average power between signals as well as noise variance of the generalized multi-carrier system receiving terminal of the DFT spread-spectrum according to the arith relation as well as the frequency field equilibria parameter, and recomputing available signal information noise ratio, so as to calculate the available signal information noise ratio of the generalized multi-carrier transmission system accurately, the method for estimating the available signal information noise ratio can be used for link self-adapting transmission solution of the generalized multi-carrier system based on Discrete Fourier Test spread-spectrum and radio material management.
一种DFT扩频的广义多载波系统的SINR估计方法，其通过首先建立所述离散傅立叶变换扩频的广义多载波传输系统的信号输入输出之间的数学关系，然后根据信道频率响应、信道噪声方差和均衡方法，设定所述DFT扩频的广义多载波传输系统的频域均衡子载波的均衡系数，再根据所述数学关系及所述频域均衡系数分别计算所述DFT扩频的广义多载波传输系统接收端有用信号的平均功率、信号间干扰的平均功率以及噪声方差，再计算有效信干噪比，如此以实现对广义多载波传输系统的有效信干噪比的准确计算，该有效信干噪比估计方法可用于基于离散傅立叶变换扩频的广义多载波传输系统的链路自适应传输方案和无线资源管理方面。
Different picket-fence window causes the different signal sample length, which will bring different results for DFT.
截断窗口长度决定了信号样本长度，不同的样本长度会影响DFT的结果。
DFT is a kind of pressure tester while drilling.
简介了当前随钻地层测试仪器的种类。
In chapter 3, Theoretical calculations for the mechanism of methane catalyzed by ligated transition metal MH+(M = Ru, Rh and Pd) have been carried out at the DFT (B3LYP) level.
第三章，我们计算研究了金属氢化物阳离子MH+(M = Ru，Rh和Pd)活化甲烷的反应。
A new technique is presented in this paper for frequency estimation of single real sinusoid at a low computational cost using the real parts or imaginary parts of Fourier coefficient s.
提出了一种利用信号离散傅里叶变换系数的实部或虚部来构造频率修正项的新算法，算法只需傅里叶系数的实部或者虚部的最大值附近的3个DFT系数来构造频率修正项，避免了复数运算从而有效减少了运算量，同时算法的频率估计精度接近CRLB(Cramer-Raolow bound)。
In this paper, the ways usually used for noise squelch in FM receiver are compared, and their implementations in digital FM receiver are specially analyzed.
静噪是FM接收机中的重要组成部分，本文比较了FM接收机中常用的静噪方法，重点分析了在FM数字化接收机中静噪功能的实现，提出了一种采用滑动DFT算法的导频静噪检测算法，并对其性能进行了分析。
It can strongly combat mutipath and dispersive channel interference. Using DFT, it can be easily reliazed in transceivers.
同时由于它采用了离散傅立叶变换，所以大大降低了收发机的实现复杂度。
Orthogonal Frequency Division Multiplexing is one of the best solutions to this problem. It can strongly combat multipath and dispersive channel interference. Using DFT, it can be easily realized in transceivers. Therefore, the application of OFDM in wireless communication systems is robust and remarkable.
正交频分复用技术具有抗多径衰落和时延弥散并且保持较高的传输速率的潜力和优势，同时由于它采用了离散傅立叶变换，大大降低了接收机的实现复杂度，因此，在无线通信领域的应用引起了广泛的关注。
Digital watermarking algorithm based on DFT was proposed by applying the phase modulation technique, the algorithm adopted two strategies — low amplitude block selection and amplitude boost to enhance its performances. The algorithm not only realized embedding watermark invisibility, but also enhanced the robustness of the watermark; embedding with large quantities of information was realized by selecting the phase difference which came from the neighboring blocks.
应用调相技术而生成的基于DFT域的数字水印算法，通过低幅度块选取及幅度增强策略，不仅实现了水印的透明嵌入，而且提高了嵌入水印的鲁棒性；通过选取块链中相邻两块对应位置处嵌入系数的相位差来嵌入信息，实现了大容量嵌入信息的目的。
Secondly, three A-B-type fluorescent copolymers comprised of alternating carbazolyl and pyridinyl units, poly[2, 7-(N-(2-ethylhexyl)carbazolyl-alt-(3, 5-pyridinyl)](PEHCP-35), poly[2, 7-(N-(2-ethylhexyl)carbazolyl-alt-(2, 6-pyridinyl)](PEHCP-26) and poly[2, 7-(N-(2-ethyl- hexyl)carbazolyl-alt-(2, 5-pyridinyl)](PEHCP-25), are studied by means of the density functional theory (DFT/B3LYP/6-31G).
其次，采用密度泛函理论(DFT/B3LYP/6-31G)研究了由咔唑和吡啶单元交错形成的三种A-B型荧光共聚物，聚(2，7-N-2-乙基己基咔唑)-交替-3，5-吡啶(PEHCP-35)，聚(2，7-N-2-乙基己基咔唑)-交替-2，6-吡啶(PEHCP-26)和聚(2，7-N-2-乙基己基咔唑)-交替-2，5-吡啶(PEHCP-25)。
In Chapter 2, we first briefly introduce some basic principles and related current progresses of DFT.
然后介绍了所采用的第一性原理软件Dmol~3的主要特征。
Chlorine trifluoride; Water; DFT; Reaction channel
C1F3； H2O ；密度泛函理论；反应通道
The paper first expounds the calculation of influence coefficient method for flexible rotor and vector influence coefficient method for flexible rotor and the calculation of phase for balance based on DFT and develops high- speed rotor vibrating balance testing system by utilizing DSP TMS320LF2407 as core chip while referring to intelligent vibrating balance instruments home and abroad.
本论文首先对不平衡算法：刚性转子影响系数法以及基于DFT的不平衡振幅、相位提取算法作了详细归纳、阐述。在参考和借鉴国内外智能动平衡仪的基础上，提出了采用DSP技术，开发转子动平衡测试系统。
Gas. We use hybrid DFT to study its electronic structure and atomic vibra
们用杂化密度泛函理论计算了其电子结构和原子振动，研究表明该分子确
They can be used to make the testability of the circuit under design best under certain hardwarecost; A example of applying DFT results into test phase is also given, in which, by using mathematic programming, we can find the proper nonuniformly distributed 0-1 signal proabilities to primary inputs of CUT during Pseudorandom testing, that will lead the test length of random testing reduces dramaticlly.
最后，我们还给出了一个可测试性设计在测试中的应用例子——求伪随机测试下原始输入信号概率的最优分布，从而使测试长度大大缩短。