协作通信中的解码转发中继策略优化

在单中继协作通信系统模型下,研究了直接传输、固定解码转发（ DF）中继、选择DF中继和增量中继协议。为了提高协作通信系统的频谱效率和中断性能,通过比较源-目的端和中继-目的端的瞬时信道增益来判定是否需要采用协同通信模式,提出一种改进的解码转发方式（ IDF）。通过将选择DF中继和增量中继的优点结合,提出了一种增量选择中继（ ISR）策略,并给出了2种改进协议任意信噪比的中断概率表达式。仿真结果表明,与传统的单中继解码转发协议相比, IDF和ISR均具有更低的中断概率, ISR具有最低的中断概率。     

非稳腔DF激光窗口热效应及其对远场光斑的影响

以非稳腔ＤＦ激光器ＣａＦ＿２输出窗口为例计算了不同输出功率情况下，窗口材料的温升、相应的波前位相变化以及有扩束系统和无扩束系统两种情况下，远场光斑所受的影响，给出了数值计算结果。     

高损伤阈值氟化氘腔镜研制

报道了氟化氘(DF)激光器腔镜的膜系设计、材料选取、制备工艺及其损伤阈值和热畸变测试结果。实验结果表明，镜面在21kW／cm^2功率密度下的热畸变为0．32左右(λ=632．8nm)，腔镜的损伤阈值大于40kW／cm^2。     

Electrically switchable reflection holograms formed using two-photon photopolymerization

Two-photon holographic photopolymerization was used to form switchable Bragg gratings composed of layers of phase-separated liquid-crystal (LC) domains interspersed with cured, crosslinked polymer. These holographic polymer-dispersed liquid crystals form a periodic structure which diffracts red light due to nanostructured planes ∼250 nm in spacing. These structures were formed by interfering two 90-fs pulses coherently upon a reactive syrup consisting of acrylate monomer, liquid crystal, and a two-photon dye. The large two-photon cross-section allows excitation of the two-photon dye that results in electron transfer between this dye and the monomer. Diffraction efficiencies of approximately 10% were obtained, which can be modulated using an electric field applied across the film. Switching speeds below 1 ms were observed due in part to the small size of the LC domains. Received: 10 April 2001 / Accepted: 1 July 2001 / Published online: 2 October 2001     

连续波DF化学激光器的数值模拟研究——不同燃料和稀释剂的性能差异

采用有限差分技术和压缩比例计算方法，对分别以Ｈ２和Ｃ２Ｈ４作燃料、以Ｈｅ和Ｎ２作稀释剂的燃烧驱动连续波ＤＦ激光器进行了数值模拟，给出了ＤＦ化学激光器燃烧室的平衡化学组分、光腔内平均小信号增益沿流场分布、激射谱线的强度分布、激光器功率和效率。计算结果表明：以Ｃ２Ｈ４作燃料、以Ｈｅ作稀释剂的ＤＦ化学激光器具有较长的可调节激活区，激光器的化学效率高，并且其激射谱线的强度分布更为集中     

连续波DF高功率激光引起的光学元件热畸变和损伤

分析了四分之一波长膜堆和金属介质增强激光反射膜的吸收，计算和测量了连续波高功率激光辐照下光学元件的热变形．对理论计算和实测结果进行了比较。     

强化学激光器的研究与发展

化学激光器是以释能化学反应提供能源, 并且以化学反应产生粒子数反转为基础的。由于化学储能的巨大, 这类器件目前输出的连续波功率已达兆瓦级, 大大高于所有其他激光器;近年来, 由于流动介质均匀性的改善和采用选摸能呼高的光腔, 光束质量亦已达到近衍射极限。近年来的研究集中在发展短波长化学激光体系, 从较早的DF(～3.8 μm), HF(2.7 μm)到近期的O2-J体系(1.315 μm), 以及HF的泛频跃迁激光(～1.35 μm)。更进一步则希望发展可见光波段的化学激光器。这有可能通过电子激发志的受激辐射实现, 但是看来尚需较长时间的努力。     

连续波激光辐照PV型HgCdTe探测器的新效应

 用连续波DF激光辐照PV型HgCdTe红外探测器，得到不同辐照功率密度下，探测器响应输出的一系列实验结果，观察到器件饱和以外的如探测器混沌、探测器单极化等一些新现象，这些结果与理论预期有着较大差别。给出了实验结果的初步解释，该实验结果为今后更好地研究PV型HgCdTe探测器提供了新的线索。     

Ion mobility spectrometric analysis of vaporous chemical warfare agents by the instrument with corona discharge ionization ammonia dopant ambient temperature operation

The ion mobility behavior of nineteen chemical warfare agents (7 nerve gases, 5 blister agents, 2 lachrymators, 2 blood agents, 3 choking agents) and related compounds including simulants (8 agents) and organic solvents (39) was comparably investigated by the ion mobility spectrometry instrument utilizing weak electric field linear drift tube with corona discharge ionization, ammonia doping, purified inner air drift flow circulation operated at ambient temperature and pressure. Three alkyl methylphosphonofluoridates, tabun, and four organophosphorus simulants gave the intense characteristic positive monomer-derived ion peaks and small dimer-derived ion peaks, and the later ion peaks were increased with the vapor concentrations. VX, RVX and tabun gave both characteristic positive monomer-derived ions and degradation product ions. Nitrogen mustards gave the intense characteristic positive ion peaks, and in addition distinctive negative ion peak appeared from HN3. Mustard gas, lewisite 1, o-chlorobenzylidenemalononitrile and 2-mercaptoethanol gave the characteristic negative ion peaks. Methylphosphonyl difluoride, 2-chloroacetophenone and 1,4-thioxane gave the characteristic ion peaks both in the positive and negative ion mode. 2-Chloroethylethylsulfide and allylisothiocyanate gave weak ion peaks. The marker ion peaks derived from two blood agents and three choking agents were very close to the reactant ion peak in negative ion mode and the respective reduced ion mobility was fluctuated. The reduced ion mobility of the CWA monomer-derived peaks were positively correlated with molecular masses among structurally similar agents such as G-type nerve gases and organophosphorus simulants; V-type nerve gases and nitrogen mustards. The slope values of the calibration plots of the peak heights of the characteristic marker ions versus the vapor concentrations are related to the detection sensitivity, and within chemical warfare agents examined the slope values for sarin, soman, tabun and nitrogen mustards were higher. Some CWA simulants and organic solvents gave the ion peaks eluting at the similar positions of the CWAs, resulting in false positive alarms.     

中、远红外双波段激光器的性能优化

对两根放电管驱动的中、远红外双波段(3～5 μm & 8～12 μm)激光器的输出镜透过率、输出窗口等器件与参数进行了优化, 试验获得了25.5 W的中、远红外双波段激光输出, 两个单波段的输出功率均大于10 W, 中红外波段DF激光为TEM00模, 远红外波段CO2激光为TEM20模.利用Φ8 mm光阑对双波段激光器的横模进行了选择, 试验获得了15.4 W的TEM00基横模双波段激光输出.为红外双/多波段探测器阵列及相关系统的应用研究提供了激光光源.