锁模半导体激光器产生带宽极限的超短光脉冲

利用主动锁模技术,以光在外腔中的往返频率调制注入电流,在外腔中加入F-P标准具(Fabry-Perot etalon)后,在国內首次获得了带宽极限的可调谐完全锁模半导体激光超短脉冲。该脉冲源可望用于高速光通信、光孤子通信等领域。     

同态滤波在扭矩载荷识别中的应用

通过理论分析和实验验证,证明了采用同态滤波的方法识别机器扭矩载荷的可行性。同时提出了根据时序模型的Ｇｒｅｅｎ函数来判定窗函数宽度的方法,减少了选取窗函数宽度的盲目性。作为应用实例,给出了采煤机扭矩的识别结果。     

Nd~(3+):YAG激光器提高输出和谱线调谐运转的实验研究

激光棒的热效应是影响固体激光器提高输出的重要因素。本文采取热补偿方式,首先测定其热焦距,确定补偿曲率,给出工艺方法,最后得到显著提高的输出,并选用实心F-P标准具和它们的组合调谐出荧光带中弱线的连续运转。     

镓铟砷磷 磷化铟掩埋新月形激光器

本文研究了一种新型的1.3μm InGaAsP/InP掩埋新月形(BC)激光器。采用两次液相外延(LPE)技术形成掩埋双異质结构(BH),p-n-p-n电流阻挡结构和窄有源区。该器件在室温连续工作条件下的阀值电流低达15mA、基横模、单面输出功率大于12mW。     

Modeling of Acoustic Signal Energies with a Generalized Frank Copula. A Linguistic Conjecture is Reviewed

In this article a generalized Frank copula was selected to model the dependence between the energy on two frequency bands of the speech signal, coming from eight languages. An algorithm was developed that uses maximum likelihood to choose the best fitting copula’s parameters. Through bootstrap, the algorithm estimates the variability of the parameters for each language and also computes confidence regions by means of Voronoi tesselations. A linguistic conjecture which claims that the languages are organized in three rhythmic classes, was confirmed by the Voronoi regions. Modeling with a uniparametric Frank copula, the different degrees of dependence between the energies were quantified.     

Does age affect the efficacy and safety of GreenLight HPS™ laser photoselective vaporization prostatectomy?

Background: To evaluate the efficacy and safety of GreenLight HPS^? (High Performance System) laser photoselective vaporization prostatectomy (PVP) for the treatment of benign prostatic hyperplasia (BPH) in patients of different age groups. Methods: 164 consecutive patients were stratified into two groups: age <70 (group I, n?=?93) and age ≥70 (group II, n?=?71) years. Transurethral PVP was performed using a GreenLight HPS? side-firing laser system. Voiding parameters were measured preoperatively and at 1 and 4 weeks and 3, 6, 12, 18, 24 and 36 months postoperatively. Results: Among the preoperative parameters evaluated, there were significant differences (p?<?0.05) in prostate volume (I: 58.7; II: 73.6?mL) and serum prostate-specific antigen (I: 1.9; II: 2.9?ng/mL), while American Urological Association Symptom Score (AUASS), Quality of Life (QoL), maximum flow rate (Qmax), Sexual Health Inventory for Men (SHIM) and post void residual (PVR) were similar (p?>?0.05) between groups. No significant differences in laser utilization, energy usage and operating time were noted. Clinical outcomes (AUASS, QoL, Qmax, PVR) showed immediate and stable improvement from baseline (p?<?0.05) within each group, but no significant differences between the two groups were observed during the follow-up period. The incidence of adverse events was low and similar in both groups. Conclusions: The results suggest that age has little effect on the efficacy and safety of GreenLight HPS? laser PVP.     

变学习速率在线ICA算法在雷达信号分选中的应用

已有的独立分量分析(ICA)雷达分选方法多采用FastICA算法,FastICA算法是一种离线批处理ICA算法,缺乏实时分选能力.文中将一种变学习速率的在线ICA算法应用到雷达分选中,克服了FastICA算法无法实现在线实时分选的缺点;同时,算法能根据相依性测度所反映的信号分离的状态自适应地调节学习速率,平衡了传统在线ICA算法收敛速度和稳态误差之间的矛盾,从而使得采用这种ICA算法的雷达信号分选方法具有收敛速度快,分离效果好的特点.仿真实验验证了分选方法的有效性.     

Double sampling |S| control chart with variable sample size and variable sampling interval

This study presents a control chart for monitoring shifts in the covariance matrix of a multivariate normally distributed process. This chart combines the double sampling, variable sample size and variable sampling interval features, and is called the DSVSSI |S| chart. A Markov chain approach is developed to design the DSVSSI |S| chart, by minimizing the average time to signal (ATS), for a specified shift size in the covariance matrix. The DSVSSI |S| chart has a better ATS performance compared to other existing charts. An example is given to illustrate the operation of the DSVSSI |S| chart.     

广州：城市博物馆的呼唤

城市博物馆是一座城市的文化之根,历史的记忆与良知,更是未来的基石。凝聚一个国家或民族,需要的是文化的认同以及对未来之保证。博物馆也是这样的认同与保证。打造好它们,需要几代乃至几十代人的精心荟萃。     

折射型微透镜列阵制作的一种新途径

介绍了一种制作折射型微透镜列阵的新方法,其主要思想参考了灰阶掩模法。所用掩模板用激光直写制作,通过一次曝光即可在光刻胶上形成折射型微透镜的轮廓,并给出了微透镜轮廓的测试图样。