Phase synchronization processing method for alternating bistatic mode in distributed SAR

In the distributed synthetic aperture radar(SAR),the alternating bistatic mode can perform phase reference without a synchronization link between two satellites compared with the pulsed alternate synchronization method.The key of the phase synchronization processing is to extract the oscillator phase differences from the bistatic echoes.A signal model of phase synchronization in the alternating bistatic mode is presented.The phase synchronization processing method is then studied.To reduce the phase errors introduced by SAR imaging,a sub-aperture processing method is proposed.To generalize the sub-aperture processing method,an echo-domain processing method using correlation of bistatic echoes is proposed.Finally,the residual phase errors of the both proposed processing methods are analyzed.Simulation experiments validate the proposed phase synchronization processing method and its phase error analysis results.     

Continuous on-line adaptation of the rotor time constant in FOC induction machine system

Rotor time constant is an important parameter for the indirect lleld oraentateO control of mauc- tion motor. Incorrect rotor tittle constant value will cause the flux observer generating a wrong angu- lar orientation of the rotor field. A new approach serves for rotor time constant on-line adaptation by setting the stator current to be zero for a short period. A smooth eorrector is designed to prevent ab- normal detection result from making adaptation. Impact of zero current duration on detection error and rotor speed is analyzed by experiments.     

Direction and polarization estimation for coherent sources using vector sensors

A two-dimensional direction-of-arrival (DOA) and polarization estimation algorithm for coherent sources using a linear vector-sensor array is presented. Two matrices are first constructed by the receiving data. The ranks of the two matrices are only related to the DOAs of the sources and independent of their coherency. Then the source’s elevation is resolved via the matrix pencil (MP) method, and the singular value decomposition (SVD) is used to reduce the noise effect. Finally, the source’s steering vector is estimated, and the analytics solutions of the source’s azimuth and polarization parameter can be directly computed by using a vector cross-product estimator. Moreover, the proposed algorithm can achieve the unambiguous direction estimates, even if the space between adjacent sensors is larger than a half-wavelength. Theoretical and numerical simulations show the effectiveness of the proposed algorithm.     

环保型涂装前处理技术开发方向

随着国家对环保的重视程度日益加深,污染防治已成为几乎所有行业,尤其是工业领域急需解决的课题。而作为前瞻技术,环保型涂装前处理技术的开发将对涂装行业甚至汽车工业产生深远的意义,尤其是纳米陶瓷锆盐处理和硅烷处理技术的成功应用必将成为涂装前处理技术上的飞跃。     

利用聚钙黄绿素薄膜修饰电极测定黄嘌呤

利用循环伏安法,制备出具有良好催化活性的聚钙黄绿素薄膜修饰电极(PCALE).利用PCALE对黄嘌呤(Xa)的电催化作用,建立了对黄嘌呤含量定量分析的电分析方法.在0.02 mol/L PBS(pH=6.8)+0.2 mol/L KNO3体系中,黄嘌呤的浓度在5.0×10-6~1.0×10-4 mol/L范围内与峰电流呈良好的线性关系,线性回归方程和线性相关系数分别为:ip=-0.010 5C-2.09,γ=0.998 9,检出限可达2×10-7 mol/L.利用该法对尿液中的黄嘌呤进行定量分析,得到满意结果.5次样品分析结果的相对标准偏差小于2%.     

基于企业服务总线的物流园区信息管理平台模型构建

采用一种与平台/编程无关的消息传递架构企业服务总线(ESB)构建物流园区信息系统平台架构,从而使物流园区能快速搭建敏捷的、按需应变的商业动态信息环境,使企业在市场上占据领先的竞争优势。     

Acquiring synonymous attribute phrases for named entities via online encyclopedia

In this work,an approach is proposed to acquire synonymous attribute phrases of named entities （NEs） from an online encyclopedia.Synonymous attribute phrases are the phrases that express the same attribute with different surface forms for a class of NEs.Specifically,the proposed approach is composed of three stages.Firstly,the entries related to a given NE class are automatically selected from an online encyclopedia.Secondly,attribute phrases are extracted based on the statistics of phrase frequency.Thirdly,synonymous attributes are identified in a pairwise manner through a classification framework combining multiple features.The proposed approach is applied on Baidu Baike,a Chinese online encyclopedia,for four different NE classes.Experimental results show that the approach obtains an average precision of 74％ and an average F-value of 65％ for the four NE classes.In particular,thousands of synonymous attribute phrase pairs are acquired for each class,which demonstrates the effectiveness of the proposed approach.     

渗透汽化分离膜及膜反应器 Ⅰ．聚离子复合腹性能的研究

通过两层复合制得壳聚糖－聚丙烯酸钠和壳聚糖－褐藻酸钠聚离子复合膜，研究了其对乙醇－水混合体系的分离性能，并比较了壳聚糖膜、聚丙烯酸钠、褐藻酸钠及聚离子复合膜对乙醇－水二元体系和乙酸－丁醇－乙酸丁酯－水多元体系的渗透汽化分离性能．结果表明，聚离子复合膜适于作膜反应器的膜材料．     

二氧化硅负载聚(丙烯腈-乙烯基三乙氧基硅烷)钯配合物的合成、加氢活性及结构表征

合成了二氧化硅负载聚(丙烯腈-乙烯基三乙氧基硅烷)钯配合物,用红外光谱、电子能谱和电子显微镜等对其结构进行了表征;研究了在常温常压下将醛酮的羰基催化氢化还原成亚甲基或甲基的反应,结果表明这种催化剂具有高选择性和高转化率的催化特性.     

藻酸双酯钠示波极谱滴定法研究

从藻酸双酯钠中水解出硫酸根，用已知过量的钡沉淀硫酸根，于ｐＨ４．３的ＨＡｃ－ＮａＡｃ缓冲溶液中，在一定量聚乙二醇（ＰＥＧ）存在下，用四苯硼钠（Ｎａ－ＴＰＢ）直接滴定剩余的钡，利用示波极谱图上ＴＰＢ切口的出现指示滴定终点．较大量的钙、镁、铝、锰等存在下不干扰测定．用于藻酸双酯钠原料药和片剂的测定，均获得满意结果，此法终点敏锐，操作简便