数字高清晰度电视地面广播COFDM传输方案

数字高清晰度电视是新一代电视的发展方向,常用的传输方案是编玛正交频分复用（ＣＯＦＤＭ）方案和大联盟（ＧＡ）的残留边带调制（ＶＳＢ）方案。文中介绍了在于ＣＯＦＤＭ的数字高清晰度电视全数字发送部分的基本传输方案和硬件实现,分析了误码率等性能,并给出了实验结果。     

墨囊多酚氧化酶在红茶加工中的应用研究

为了研究经提取并纯化后的墨鱼墨中多酚氧化酶(PPO)的酶活性及其在红茶饮料加工中的应用,以新鲜墨鱼墨囊为PPO提取原料,用p H7.2磷酸盐缓冲液初步提纯,粗酶液又经饱和度为30%-80%硫酸铵分级沉淀,得到纯化倍数为3.09,酶活性达到199450u的PPO粗酶液。为探寻墨囊PPO在红茶饮料加工中的最佳工艺方案,通过单因素实验和正交试验以及感官评定试验,确定其在红茶饮料加工中应用的最佳工艺条件为:酶添加量为0.05%(m/v),反应温度为50℃,反应体系pH为8.0。     

Construction of some new families of nested orthogonal arrays

Nested orthogonal arrays have been used in the design of an experimental setup consisting of two experiments, the expensive one of higher accuracy being nested in a larger and relatively less expensive one of lower accuracy. In this paper, we provide new methods for constructing two types of nested orthogonal arrays.     

基于正交试验的雾化施液抛光工艺参数研究

为了研究雾化施液化学机械抛光工艺参数对抛光效果的影响,以抛光盘转速、抛光压力、雾化器电压、氧化剂质 量分数为因素,以材料去除率和表面粗糙度为评价指标设计正交试验,再对试验结果进行直观分析和权矩阵分析,得到 了各因素对试验结果的影响趋势和程度,并得到了最佳参数组合。结果表明：在雾化施液抛光过程中抛光效果随抛光盘 转速的增大而增大;随抛光压力的增大呈先增大后减小的趋势;随雾化器电压的增大而增大;随氧化剂质量分数的增大 而增大。且影响程度顺序由大到小为：氧化剂质量分数、抛光压力、雾化器电压、抛光盘转速。当抛光盘转速为60 r／ mm、抛光压力48 kPa、雾化器电压55 V、氧化剂质量分数为2.5%时,得到材料去除率和表面粗糙度均达到最佳,此时的 抛光效果最好。     

罗汉果有效成分提取工艺的研究

罗汉果是广西特产,罗汉果属植物的果实。在单因素实验的基础上,利用微波萃取系统,进行二次回归旋转正交组合实验,确定了微波辐射条件下不同的物理参数（辐射功率、辐射时间、溶剂量等）对提取率的影响,优化的微波辅助提取最适工艺条件是：乙醇浓度40％;微波辐射功率495W;辐射时间6min;提取压力0．1MPa;原料粉碎度100目;固液比1：30。在此条件下,罗汉果皂苷一次提取率可达76％。     

一种复合控制器在直流调速系统中的应用

提出一种复合正交神经网络控制与传统PID控制相结合的复合控制器，仿真结果表明，相对于常规PID控制器，该复合控制器具有自学习和自适应功能，速度跟踪获得了满意的控制效果．     

利用正交直积态的量子密钥分配协议

基于量子密钥分配协议是目前实现密钥分配最安全的方法,两个三态量子位组成的复合系统中存在一组正交直积态,它可以表现出非定域性。该文提出了一个建立在该系统的非定域性基础上的量子密钥分配协议,协议双方通过交换量子位和集体测量建立起共享的密钥。量子力学的基本原理保证了该协议是无条件安全的,没有第三方可以窃取密钥而不被发现。该协议不需要纠缠态,也不需要做任何量子操作。因此,它更容易在实践中实现,同时具有更高的可靠性与健壮性。     

EQUINEIGHBOURED XPERIMENTAL DESIGNS

This paper introduces a new class of designs called equi-neighboured designs. An equineighboured design has the property that every unordered pair of treatments occurs as nearest neighbours equally frequently at every level. These designs are defined in Section 4 and shown to be balanced when neighbouring observations are correlated. Some equineighboured designs are constructed using a complete set of orthogonal Latin squares. Cyclic equineighboured designs are also defined.     

Estimating Mixing Densities in Exponential Family Models for Discrete Variables

This paper is concerned with estimating a mixing density g using a random sample from the mixture distribution f(x)=∫f x | θ)g(θ)dθ where f(· | θ) is a known discrete exponen tial family of density functions. Recently two techniques for estimating g have been proposed. The first uses Fourier analysis and the method of kernels and the second uses orthogonal polynomials. It is known that the first technique is capable of yielding estimators that achieve (or almost achieve) the minimax convergence rate. We show that this is true for the technique based on orthogonal polynomials as well. The practical implementation of these estimators is also addressed. Computer experiments indicate that the kernel estimators give somewhat disappoint ing finite sample results. However, the orthogonal polynomial estimators appear to do much better. To improve on the finite sample performance of the orthogonal polynomial estimators, a way of estimating the optimal truncation parameter is proposed. The resultant estimators retain the convergence rates of the previous estimators and a Monte Carlo finite sample study reveals that they perform well relative to the ones based on the optimal truncation parameter.     

压铸机合模机构的正交回归优化设计

在对压铸机合模机构的优化设计中,采用正交回归设计法建立结构性能与设计变量的近似函数,对近似函数进行优化,从而有效地解决了结构优化设计过程中优化方法需要反复进行三维有限元分析而引起的超大计算量问题;这种方法对实际应用中大量存在而又无法得到解析式的结构优化问题有着普遍的意义。