高炮火控系统滤波器的设计

对目前高炮火力控制系统目标滤波与预测进行了分析与研究．在此基础上结合工程实际设计了一种α-β滤波器．该滤波器的原理是把在连续系统中频率域的要求和在离散系统中Z域的要求转换成时域中在典型信号激励下的时间响应的特征值的要求．从而在时间域中以特征值的要求进行综合．再把综合的结果转换回Z域中．最终得到所确定的α-β滤波器．文中给出了α-β滤波器的Z传递函数．分析了α-β滤波器参数的确定．对α-β滤波器的静态误差进行了研究．对设计方案进行了计算机仿真和实际应用．     

Single-longitudinal-mode fiber ring laser employing an equivalent phase-shifted fiber Bragg grating

A novel single-longitudinal-mode (SLM) fiber ring laser that incorporates an equivalent phase-shifted fiber Bragg grating acting as an ultra-narrow bandpass filter in the laser cavity is proposed. The equivalent phase-shifted fiber Bragg grating has an ultra-narrow transmission bandwidth which ensures an SLM lasing. Stable SLM operation without mode hopping is demonstrated.     

An experimental study of carrier heating on channel noise in deep-submicrometer NMOSFETs via body bias

In this paper, RF noise in 0.18-mum NMOSFETs concerning the contribution of carrier heating and hot carrier effect is characterized and analyzed in detail via a novel approach that modulates the channel carrier heating and number of hot carriers using body bias. We confirm qualitatively a negligible role of hot carrier effect on the channel noise in deep-submicrometer MOSFETs. For a device under reverse body bias (V_b), even though the increase in hot carrier population is clearly characterized by dc measurements, the device high-frequency noise is found to be irrelevant to the increase in the channel hot carriers. Experimental results show that the high-frequency noise is slightly reduced with the increase in |V_b|, and can be qualitatively explained by secondary effects such as the suppression of nonequilibrium channel noise and substrate induced noise. The reduction of NF_min and R_n with the increase in |V_b| may provide a possible methodology to finely adjust the device high-frequency noise performance for circuit design     

Morphology and properties of poly[2‐methoxy‐5‐(2′‐ethyl‐hexyloxy)‐para‐phenylene vinylene]/silica nanoparticle hybrid films

Poly[2‐methoxy‐5‐(2′‐ethyl‐hexyloxy)‐para‐phenylene vinylene] (MEH‐PPV)/silica nanoparticle hybrid films were prepared and characterised. Three kinds of materials were compared: parent MEH‐PPV, MEH‐PPV/silica (hybrid A films), and MEH‐PPV/coupling agent MSMA/silica (hybrid B films), in which MSMA is 3‐(trimethoxysilyl) propyl methacrylate. It was found that the hybrid B films could significantly prevent macrophase separation, as evidenced by scanning electron and fluorescence microscopy. Furthermore, the thermal characteristics of the hybrid films were largely improved in comparison with the parent MEH‐PPV. The UV‐visible absorption spectra suggested that the incorporation of MSMA‐modified silica into MEH‐PPV could confine the polymer chain between nanoparticles and thus increase the conjugation length. The photoluminescence (PL) studies also indicated enhancement of the PL intensity and quantum efficiency by incorporating just 2 wt% of MSMA‐modified silica into MEH‐PPV. However, hybrid A films did not show such enhancement of optoelectronic properties as the hybrid B films. The present study suggests the importance of the interface between the luminescent organic polymers and the inorganic silica on morphology and optoelectronic properties. Copyright © 2004 Society of Chemical Industry     

Preparation of flexible polyhedral particles via concentrated emulsion templating polymerization

This paper presents recent efforts on the preparation of flexible polyhedral particles via concentrated emulsion templating polymerization in which the hydrophilic monomer (acrylamide) and hydrophobic monomer (butyl acrylate) are polymerized simultaneously in the continuous and dispersed phase, respectively. Such templating polymerization has been enhanced in our systems owing to the introduction of acrylamide monomer and their higher polymerization rate in continuous phase as compared with butyl acrylate in dispersed phase. Diffusion between the different phases was also inhibited. Furthermore, the stability of the concentrated emulsion and the molecular weight of the produced poly(butyl acrylate) were found to be significantly affected by the amount of redox initiator. The morphology of the particles could be controlled by varying the volume fraction of the dispersed phase and the polyhedral particles were achieved at higher volume fraction. Copyright © 2005 Society of Chemical Industry     

川西低渗气藏单井地应力计算方法综合研究

四川盆地新场气田是一个低孔低渗的裂缝性砂岩气田，储层物性差，自然产能低，需经压裂后才能投产，压裂后气井增加的产能与压裂的效果密切相关。提前认识储层当前地应力的特征，有助于压裂设计时确定裂缝产状、缝长、缝宽等参数，减少储层水力压裂改造的盲目性，降低中、低渗透油气田开发的风险。通过大量测井资料的计算，确定了新场气田储层地应力的大小和方向，并综合采用微地震测量、岩石声发射资料、古地磁等岩心测试资料和水力压裂等多种方法进行交互验证，各种方法求得的地应力特征十分相近，说明利用测井资料求取储集层地应力原理简单，计算结果符合实际的地应力特征，是一种低风险研究计算储层地应力特征的方法，可以用于指导低渗透油气田的井网部署和储层的单井压裂改造。     

提高小样试织质量的措施

介绍了纺织品小样试织时，为了提高试织质量在经纬纱准备及织造工序时所采取的一些措施。     

电信大客户业务组网现状分析

前言随着电信市场竞争越来越激烈,各种电信业务资费呈下降趋势,因此大客户原来主要采用低速专线来组织其内部通信网的方式也发生变化,逐渐采用高速的2M电路或者LAN专线、VPN等IP电路进行组网。目前大客户主要分布在金融、政府、行政、外企、交通等行业,其采用运营商电路来组织其内部通信网络以满足中心网点与各个分支网点、分支机构的语音、数     

Tile-boundary artifact reduction using odd tile size and the low-pass first convention.

It is well known that tile-boundary artifacts occur in wavelet-based lossy image coding. However, until now, their cause has not been understood well. In this paper, we show that boundary artifacts are an inescapable consequence of the usual methods used to choose tile size and the type of symmetric extension employed in a wavelet-based image decomposition system. This paper presents a novel method for reducing these tile-boundary artifacts. The method employs odd tile sizes (2N + 1 samples) rather than the conventional even tile sizes (2N samples). It is shown that, for the same bit rate, an image compressed using an odd tile length low-pass first (OTLPF) convention has significantly less boundary artifacts than an image compressed using even tile sizes. The OTLPF convention can also be incorporated into the JPEG 2000 image compression algorithm using extensions defined in Part 2 of this standard.