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1.
一种全光纤电子电压互感器的研究   总被引:4,自引:0,他引:4  
娄凤伟  郑绳楦  王建军 《光电工程》2006,33(7):123-126,130
基于石英晶体的逆压电效应,研制出一种双模干涉式的电子电压互感器。该互感器利用两个低阶模的干涉原理改善了电压互感器的性能,为消除外界干扰、提高系统的测量精度提供理论根据。实验表明:在.40℃~+40℃的温度范围内,互感器能达到0.2级的准确度。  相似文献
2.
雷达间或工作下雷达/红外融合跟踪   总被引:1,自引:1,他引:0  
针对强对抗条件下末制导导弹寻的问题,本文提出一种雷达间或工作的雷达红外双模导弹融合跟踪算法.设计了雷达/红外双模导引头协同工作模式,通过机动目标检测算法来判断雷达开机的时刻,从而减小敌机告警器告警概率、敌机导弹拦截概率和敌机电子支援措施锁定概率;并且,为了改善跟踪精度,将交互式多模型算法(IMM)算法和不敏卡尔曼滤波(UKF)算法结合起来,将其运用在雷达红外双模融合跟踪中.实验结果表明,与单独的红外跟踪相比,该方法能有效减少雷达开机时间,不仅提高了跟踪精度,而且增大了导弹击中目标的概率.  相似文献
3.
一种基于PSO算法的非线性模型预测控制方法   总被引:1,自引:0,他引:1  
将微粒群优化(PSO)算法用于输入受限非线性系统,提出了一种基于PSO的非线性模型预测控制算法.该算法采用双模控制策略,将保证预测控制稳定性的终端等式约束转化为终端不等式约束,推导出使系统稳定的不变可行集.在不变集外,利用PSO算法优化求解预测控制律,使系统状态进入不变集;在不变集内,利用线性状态反馈使系统状态渐近稳定.同时对算法的稳定性进行了分析.仿真结果证明了该算法的可行性和有效性.  相似文献
4.
We report, for the first time to our knowledge, a clear resonant peak split in the range of 7.7–9.7 GHz in a perturbed dual-mode disk-type resonator (DMDR) made of YBa2Cu3O7–x (YBCO) superconducting thin film on MgO substrate. Epitaxial YBCO superconducting thin films were grown on (100) MgO substrates by pulsed laser deposition technique. The critical temperature of superconducting thin film on MgO substrate was 85 K. Superconducting dualmode disk resonators were designed by microwave design software, EEsof, and patterned by photolithography and a wet-etch process. The unloaded quality factor (QUL) of the superconducting DMDR was found to be 1,312 at 77 K. We believe this type of DMDR can be utilized for dual-mode resonator-based filters for satellite communications.  相似文献
5.
Passive microwave filters based on high temperature superconducting (HTS) films are very promising for telecommunication applications. Filters based on a dual-mode configuration present the appealing combination of high power handling capability and excellent miniaturization. Here a new kind of dual-mode filter based on cross-slotted square resonators is presented. The novelty of this structure is related to the use of a pair of unequal crossed slots formed on a square patch resonator, so that the size of the device can be significantly reduced. Single stage dual-mode filters are designed with a commercial 2.5D software at frequencies of interest for satellite communications. Prototypes based on a square resonator with 6 mm side operating at 3.7 GHz are fabricated using Nb double-sided films grown on 10 × 10 × 0.5 mm3 LaAlO3 substrates. The response is measured at 4.2 K and the nonlinearity is investigated observing the power degradation. The effect of additional cuts, opportunely realized on the conductor surface, is discussed in respect to the size reduction and the maximum circulating power. It is found that the resonant frequency can be reduced from 3.7 to 3.3 GHz without affecting the power handling capability.  相似文献
6.
针对现有融合算法在处理红外偏振和光强两种模态图像时无法随着差异特征的不同而变化的问题,提出了一种双模态红外图像的集值映射融合方法。以多组红外偏振和光强图像为训练样本,根据底层特征的融合算法的类型分别建立差异特征类集和融合算法类集;构造各个差异特征对应各融合算法的融合有效度分布;通过多组图像融合有效度分布的均值聚合,建立全局图像的差异特征与融合算法的集值映射关系;提取被融合图像的差异特征,根据集值映射选择相应算法,通过各算法的组合得到融合结果。实验表明,该融合方法可以优化选择融合算法,将互补性强的差异特征有效融合。  相似文献
7.
针对目前常见风冷冷水机组节能空间有限的问题,提出采用机械制冷和自然冷却模块化设计的双模风冷冷水机组。以北方某地区一冷水系统为例,分析双模风冷冷水机组的节能性,为北方需要常年制冷的大型计算机或大功率发热设备冬季运行提供比较适用的方案。  相似文献
8.
A universal platform with Mn doping and hyaluronic acid (HA) modification, based on mesoporous silica (mSiO2), was designed and used as a basic multifunctional material with magnetic resonance (MR) imaging. Furthermore, we added flexible functions through the addition of functional molecules. Specially, two typical compounds, hydrophobic perfluorooctyl bromide (PFOB) and hydrophilic doxorubicin (DOX), were loaded into the channels to obtain PFOB@Mn@mSiO2@HA (PMMH) or DOX@Mn@mSiO2@HA (DMMH) nanoparticles for dual-mode imaging or imaging and therapy, respectively. The PMMH and DMMH nanoparticles were highly targeted to the lymph system in vitro and in vivo. MR and ultrasound imaging of PMMH nanoparticles were performed in the lymph system, while MR imaging and chemotherapy of DMMH nanoparticles was used to detect cancer. These results showed that both PMMH and DMMH nanoparticles can be designed with high lymph targeting efficiency. PMMH nanoparticles are a dual-mode contrast agent for both ultrasound and MR imaging for the lymph system and DMMH nanoparticles are powerful agents for the combined diagnosis and therapy of cancer in vivo.
  相似文献
9.
The large‐dimensional and rigid ceramic bulks fabricated by high‐temperature solid‐phase reaction and sintering have never been considered for possibly entering and circulating within the blood vessels for biomedical applications, especially on combating cancer. Here, it is reported for the first time that MAX ceramic biomaterials exhibit unique functionalities for dual‐mode photoacoustic/computed tomography imaging and are highly effective for in vivo photothermal ablation of tumors upon being exfoliated into ultrathin nanosheets within atomic thickness (MXene). As a paradigm, 2D ultrathin tantalum carbide nanosheets (Ta4C3 MXenes) with nanosized lateral sizes are successfully synthesized based on a two‐step liquid exfoliation strategy of MAX phase Ta4AlC3 by combined hydrofluoric acid (HF) etching and probe sonication. The structural, electronic, and surface characteristics of the as‐exfoliated nanosheets are revealed by various characterizations combined with first‐principles calculations via density functional theory. Especially, the superior photothermal‐conversion performance (efficiency η of 44.7%) and in vitro/in vivo photothermal ablation of tumor by biocompatible soybean phospholipid‐modified Ta4C3 nanosheets are systematically revealed and demonstrated. Based on the large family members of MXenes, this work may offer a paradigm that MXenes can achieve the specific biomedical applications (here, theranostic) providing that their compositions and nanostructures are carefully tuned and optimized to meet the strict requirements of biomedicine.  相似文献
10.
为实现隔行扫描到逐行扫描的视频扫描格式转换,提出了一种时空权重和边缘自适应的去隔行算法,主要包括运动估计、小角度边缘搜索、时空权重计算、自适应插值等。该算法通过4场相邻像素的最大灰度变化与运动阈值比较实现对当前像素的运动估计,采用自适应搜索半径和并行搜索树的方法实现小角度边缘检测,并且增加对半像素边缘的考虑实现最小6°边缘的检测,最后通过时空权重自适应的插值算法实现去隔行处理,取得很好的处理效果。  相似文献
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