回射激光的红外主动跟踪闭环研究

根据激光辐照典型红外光学系统产生回射激光的特性分析,红外装置中焦面上调制盘前表 面产生的回射激光特别适合于激光对红外装置的远距离跟踪、瞄准和工作模式识别。用0.53μm激光辐照红外光学系统产生的回射激光信号触发1.06μm主激光控制系统,实现了主激光对红外装置输出信号的有效干扰。它对利用激光进行红外对抗研究具有重要的参考价值。

红外系统对入射激光的回射特性研究

介绍了红外系统的光学特性,从理论和实验上验证了激光辐照典型红外系统产生的回射激光。通过实验测 量了红外系统内光学元件产生回射激光的效率、光斑尺寸,分析了对回射激光光斑的识别。研究结果对充分利用回射激 光,开展激光对红外系统的主动跟踪、识别闭环具有一定的实际意义。

The internal COF features in Dome A of Antarctica revealed by multi-polarization-plane RES

The ice exceeding one million years old has significant meaning for verifying and interpreting the middle Pleistocene transition （MPT） and the relationship between greenhouse gas and climate change. The region near Dome A in Antarctica satisfies the conditions for obtaining million-years-old ice since it has low temperatures and low accumulation rates. We analyze the corresponding relation between radar wave features and the crystal orientation fabric （COF） types based on the results of multi-polarization plane radio echo sounding （RES）. The results show that, even in the summit of the ice sheet, the COF type is not perfect, but is an elongated single-pole COF. Principal-axis-orientation differences of the COF among the different periods exist and reveal that the ice flow orientations are not constant but deviate clockwise with the increasing depth. This may be related to the adjacent basal valley or both height and position changes of the summit during the glacial-interglacial periods.

激光军事应用

TN249 2004010241 评述美国天基激光计划的重大调整=Review of significantadjustment of American space-based laser program[刊,中]/任国光(北京应用物理与计算数学研究所.北京(100088))∥激光与红外.—2003,33(3).—163-166 评述了美国导弹防御局中止“天基激光综合飞行实验”计划及其带来的影响,从美国当前的军事需求以及天基激光本身存在的技术和作战问题,分析厂原因。

跟踪、瞄准、光电对抗设备

TN97 200401076 一种新的红外目标跟踪方法=New tracking method for Ⅱtargets[刊,中]/李熙莹(北京理工大学光电工程系.北京(100081)),倪国强…∥光电工程.—2003,30(1).

镭射影碟的保养

随着人们生活水平的提高,镭射影碟机已进入了寻常百姓家。一张影碟少则几十元多则几百元,影碟片的保养在消费中越来越受到重视。下面向你介绍保养镭射影碟主要应注意的问题。

新型自动装配线

介绍了美国人在墨西哥城的一个工厂建立的汽车发动机铝阀头新型自动化装配线。该装配线的生产率为160个阀头/小时。指出，可使该装配线适用于解决其他工艺问题。该装配线包括一个回射激光检查站和2台自动压机。简要地叙述了上述装配线所实现的工艺过程。

An Integratable Distributed Bragg Reflector Laser by Low-Energy Ion Implantation Induced Quantum Well Intermixing

An integratable distributed Bragg reflector laser is fabricated by low energy ion implantation induced quantum well intermixing.A 4 6nm quasi continuous wavelength tuning range is achieved by controlling phase current and grating current simultaneously,and side mode suppression ratio maintains over 30dB throughout the tuning range except a few mode jump points.

Study on QSAR of Taxol and its Derivatives Based on Stepwise Multivariate Linear Regression Analysis

Abstract Using the method of stepwise multivariate linear regression (SMLR), the quantitative structure activity relationships (QSAR) of two isomeric series of taxol and its derivatives have been studied. It was found that the molar refractivity of the C3′substituent of the C13 side chain has significant correlation with its activity. We deduce that structural changes in the C3′substituents may be critical to the anticancer function. It would be useful to the design and synthesis of taxol like compounds with improved activities.

Expressway traffic flow prediction using chaos cloud particle swarm algorithm and PPPR model

Aiming at the real-time fluctuation and nonlinear characteristics of the expressway short-term traffic flow forecasting the parameter projection pursuit regression PPPR model is applied to forecast the expressway traffic flow where the orthogonal Hermite polynomial is used to fit the ridge functions and the least square method is employed to determine the polynomial weight coefficient c.In order to efficiently optimize the projection direction a and the number M of ridge functions of the PPPR model the chaos cloud particle swarm optimization CCPSO algorithm is applied to optimize the parameters. The CCPSO-PPPR hybrid optimization model for expressway short-term traffic flow forecasting is established in which the CCPSO algorithm is used to optimize the optimal projection direction a in the inner layer while the number M of ridge functions is optimized in the outer layer.Traffic volume weather factors and travel date of the previous several time intervals of the road section are taken as the input influencing factors. Example forecasting and model comparison results indicate that the proposed model can obtain a better forecasting effect and its absolute error is controlled within [-6,6] which can meet the application requirements of expressway traffic flow forecasting.

Some Suggestions Improving Apollo Lunar Laser Retroreflector Arrays

According to our engineering research on satellite-borne laser retroreflector array, some suggestions are proposed on how to manufacture a new Apollo LLRA that can make us measure one illuminating point and unilluminating area on the moon's surface. These suggestions are: to control the dihedral angle offset within ± 0.1″; to use the larger aperture of the transparent face of cube corner prisms; to investigate how to separate out Apollo's reflected laser from mixed beam hitting on the LLR system.

Radiation Recall Reaction:Two Case Studies Illustrating an Uncommon Phenomenon Secondary to Anti-Cancer Agents

Radiation recall phenomenon is a tissue reaction that develops throughout a previously irradiated area,precipitated by the administration of certain drugs.Radiation recall is uncommon and easily neglected by physicians;hence,this phenomenon is underreported in literature.This manuscript reports two cases of radiation recall.First,a 44-year-old man with nasopharyngeal carcinoma was treated with radiotherapy in 2010 and subsequently developed multi-site bone metastases.A few days after the docetaxel-based chemotherapy,erythema and papules manifested dermatitis,as well as swallowing pain due to pharyngeal mucositis,developed on the head and neck that strictly corresponded to the previously irradiated areas.Second,a 19-year-old man with recurrent nasal NK/T cell lymphoma initially underwent radiotherapy followed by chemotherapy after five weeks.Erythema and edema appeared only at the irradiated skin.Both cases were considered chemotherapeutic agents that incurred radiation recall reactions.Clinicians should be knowledgeable of and pay attention to such rare phenomenon.

The Country and The City Redux： Mapping Contemporary Britain in Granta＇ s 2013 ＂Best of Young British Novelists＂

Drawing upon the writings of British cultural critic Raymond Williams, this article examines a pervading concern with representations of the city and the countryside as political sites and wider symbols of contextual social and economic shifts in the Granta 2013 list of Best of Young British Novelists. The article argues that the 2013 Granta list examines Williams＇ legacy from a twenty-first century perspective, offering a range of fictions that represent the rapidly changing socio-political, cultural and economic landscapes of contemporary Britain. Through textual analysis and contextualized readings, it suggests that the novels featured on the 2013 list do not offer a purely pastoral view of Britain, but use the natural world as a platform to stage wider discussions regarding a range of present-day issues.

Electro-optical Properties of Liquid Crystal Composite Materials

The liquid crystal composite materials consist of microdroplets of liquid crystals which are spontaneously formed in a matrix of a polymer at the time of its polymerization. The director configuration in liquid crystal droplets, the model of orientation of droplets, and the contrast ratios of a cell are investigated. Droplet size, spacing and distribution are readily controlled in these materials to allow optimization of displays based upon electrically controlled light scattering from the liquid crystal droplets. Preliminary experimental and theoretical studies of the light scattering and electro-optic response of new material show that these materials can offer new features suitable for large area displays and light valves.

Friction contact mechanisms of layered surface

In this paper,we firstly review the carbon layered surface prepared with electron cyclotron resonance (ECR) plasma sputtering. Secondly,the friction behavior of carbon layered surface under pin-on-disk testing is described. Furthermore,the contact stress evolution processes of layered surface with and without transfer layer during wear are given for understanding the contact mechanisms. Finally,a three-dimension (3D) local yield map of layered surface is introduced,which is useful to predict the possible contact mechanisms.

Characteristic Analysis of Underwater Acoustic Scattering Echoes in the Wavelet Transform Domain

Underwater acoustic scattering echoes have time–space structures and are aliasing in time and frequency domains. Different series of echoes properties are not identified when incident angle is unknown. This article investigates variations in target echoes of monostatic sonar to address this problem. The mother wavelet with similar structures has been proposed on the basis of preprocessing signal waveform using matched filter, and the theoretical expressions between delay factor and incident angle are derived in the wavelet domain. Analysis of simulation data and experimental results in free-field pool show that this method can effectively separate geometrical scattering components of target echoes. The time delay estimation obtained from geometrical echoes at a single angle is consistent with target geometrical features, which provides a basis for object recognition without angle information. The findings provide valuable insights for analyzing elastic scattering echoes in actual ocean environment.

No changes in densities of cannabinoid receptors in the superior temporal gyrus in schizophrenia

Objective In recent years,abnormal changes in the endocannabinoid system have been found in schizophrenia. The superior temporal gyrus（STG）is strongly implicated in the pathophysiology of schizophrenia,particularly with regards to auditory hallucinations.In this study,we investigated the binding density of cannabinoid CB1 receptors in the STG of schizophrenia patients compared to control subjects.Methods Quantitative autoradiography was used to investigate the binding densities of[^3H]SR141716A（a selective antagonist）and[^3H]CP-55940（an agonist）to the CB1 receptors in the STG.Post-mortem brain tissue was obtained from the NSW Tissue Resource Centre（Australia）.Results Contrasting to previous findings in the alterations of CB1 receptor densities in the prefrontal,anterior and posterior cingulate cortex of schizophrenia,which were suggested to be associated to impairment of cognition function,no significant difference was found between the schizophrenia and control cases in both[^3H]SR141716A and[^3H]CP-55940 binding. Conclusion We suggest that CB1 receptors in the STG are not involved in the pathology of schizophrenia and the auditory hallucination symptom of this disease.

Magnetic Resonance Urography and X-ray Urography Findings of Congenital Megaureter

Objective To observe the imaging findings of congenital megaureter in order to enhance the understanding of this disease. Methods Image data of 5 patients with congenital megaureter and 2 misdiagnosed patients were analyzed, and image findings of congenital megaureter were summarized. Elscint Prestig 2.0T superconductive magnetic resonance urography （MRLI） with conventional sequence （spin-echo, T 1W1560 ms/16 ms; fast spin-echo, T2WI 9600 ms/96 ms） was performed. Raw data were acquired with fast spin-echo sequence from heavy T2-weighted image （9600 ms/120 ms）. Post-processing method of MRH was the maximum in- tensity projection with three-dimensional reconstruction in the workstation. Intravenous pyelography （IVP） was conducted, in which X-ray films were taken 7 minutes, 15 minutes, and 30 minutes after injecting contrast agent, except that in 2 patients the films were taken delayed at 60 and 90 minutes. X-ray retrograde pyelography was performed on 2 patients, successful in one but failed in the other. Results The dilated ureter showed hypointensity on T1-weighted images and hyperintensity on T2-weighted images in conventional MRI. The mass wall was intact, uniform in thickness, and showing hy- pointensity on Tl-weighted and T2-weighted images. The MRH images showed a retroperitoneal mass appearing as an elongated tubular cystic structure spreading from kidney to bladder. MRLI also revealed dilated calices and renal pelvis, pelviureteric obstruction, and renal duplication. The main signs of congenital megaureter in X-urography was significant dilatation of ureter, or normal renal pelvis with ureter dilatation, hydronephrosis, deformity, and displacement. Conclusions MRH with X-urography could visualize the characteristics of congenital megaureter, including the dilation of renal pelvis and ureter, calculi, urinary tract duplication, and stenosis location. The two techniques can complement each other in disease diagnosis and provide more detailed information for preoperative treatment.