美军联合全域指挥控制发展浅析

为应对未来大国高端对抗,美军认为必须在各军种和各作战域开展协同作战,通过跨域无缝的指挥控制实现高效的进攻和防御效果.为此,2019年,美参联会提出建设联合全域指挥控制(JADC2)能力,并从作战条令、系统研制、技术开发和演习试验等各个层面积极开展能力建设.文中分析美军联合全域指挥控制的发展背景、内涵特点、发展态势、可能...     

短波多径环境中一种DOA方法

短波通信存在着多径衰落和干扰的问题,影响了通信的质量。通过使用智能天线,可以提高通信质量和可靠性。但是短波多径环境中会产生多个相干信号,造成智能天线的波达方向（DOA）识剥模糊。本文利用短波信号的循环平稳特性,结合均匀线性阵列,提出了在短波环境中识别DOA的前向空间平滑Cyclic Music方法。     

Dual-wavelength synchronously mode-locked Tm-doped bulk laser with terahertz frequency beating

A dual-wavelength synchronously mode-locked homogeneously broadened bulk laser operating at 1985.6 and1989 nm is presented for the first time, to the best of our knowledge, which delivers a maximum output power of 166 m W and a repetition rate of 85 MHz. The pulse duration was measured to be 16.8 ps by assuming a sech~2 pulse shape. The recorded autocorrelation trace showed frequency beating signals with an interval of 3.8 ps and a full width at half-maximum duration of 2 ps, corresponding to an ultrahigh beating frequency of about0.26 THz, which agrees well with the frequency difference of the emitted two spectral peaks. The results indicated that such a kind of dual-wavelength mode-locked Tm:YAlO_3 laser could be potentially used for generating terahertz radiations.     

ErLaP_5O_（14）非晶上转换发光分析

测量了Ｅｒ０．１Ｌａ０．９Ｏ１４非晶在６４９．０ｎｍ脉冲染料激光泵浦下的上转换荧光谱线（５５２．２，５４５．７，５４２．９）ｎｍ，５２５．０ｎｍ．４６８．８ｎｍ，４５２．２ｎｍ．（４１１．２，４０７．０）ｎｍ，３８４．１ｎｍ．３８０．７ｎｍ，其中（５５２．２，５４５．７，５４２．９）ｎｍ，（４１１．２．４０７．０）ｎｍ．３８４．１ｎｍ话线是共振步进双光子吸收导致的，而４６８．８ｎｍ．４５２．２ｎｍ，３８０．７ｎｍ是三光子荧光。     

Security analysis of a spatiotemporal-chaos-based cryptosystem

An S-box modified one-way coupled map lattice is applied as a chaotic cryptograph. The security of the system is evaluated from various attacks currently used, including those based on error function analysis, statistical property analysis, and known-plaintext and chosen-ciphertext analytical computations. It is found that none of the above attacks can be better than the brute force attack of which the cost is exhaustively quantitated by the key number in the key space. Also, the system has fairly fast encryption (decryption) speed, and has extremely long period for finite-precision computer realization of chaos. It is thus argued that this chaotic cryptosystem can be a hopeful candidate for realistic service of secure communications.     

HoP5O14非晶的上转换发光动力学研究

频率上转换现象的研究发展于 ９０年代，这是由于 ＢａＹ２Ｆ８， ＢａＹＹｂＦ８， ＺＢＬＡＮ， ＲｅＰ５Ｏ１４； ＹＬＩＦ４等激光新材料的迅速发展和激光新技术的开拓特别是半导体激光器的迅猛发展．激光二极管泵浦的固体激光器件以其特有的高效、紧凑、稳定、长寿命和全固态等优点，迅速成为国际上激光技术发展的重点，带动了固体激光研究的复兴．在半导体激光器的迅猛发展中，其输出功率的提高以及每瓦售价的降低速度是最令人吃惊的，这也特别使频率上转换激光器的研究和开发应用充满了活力． 本文选择固定 ＤＣＭ染料激光波长分别为…     

WCl_4(OR)_2Al(i-Bu)_3体系合成1,2-聚丁二烯的研究

分析了五种醇与WCl_6在室温下交换反应产物氯含量,表明产物中W:Cl=1:4,故产物可写为WCl_4(OR)_2。以WCl_4(OR)_2-Al(i-Bu)_3为催化体系,在加氢汽油溶剂中可使丁二烯聚合,得到1,2-链节含量在80％,全同立构体在60％以上的聚合物。几种醇中,以n-C_(10)H_(21)OH交换产物的催化活性最高。各种聚合条件的改变,对聚合物微观结构及分子量分布影响不明显。     

Reactive Coupling Effects on Amplitude Death of Coupled Limit-Cycle Systems

Amplitude death in coupled limit-cycle systems induced by the reactive coupling is studied. The presence of reactive coupling parameter changes the amplitude death process of the system, and increases the critical coupling strength for the emergence of amplitude death. When the systems are in the state of complete or partial amplitude death, increasing the reactive coupling will increase the number of partial synchronization groups, implying the increase of disorder of the system. Increasing the reactive coupling makes the elimination of the amplitude death of the systems harder.     

混合型双零色散大模场面积多孔光纤特性研究

利用有限元数值分析方法研究了混合型PCF(光子晶体光纤)的色散、损耗、模场面积和非线性等特性。仿真结果表明:混合型PCF在0.6～2.0μm波长范围内的限制损耗降至10-6 dB/m量级,并且满足双零色散点的需求,同时这种混合型PCF的模场面积在长波长范围内达到了755μm2,非线性系数为1.039×10-4 m-1 W-1,适合用做高功率窄线宽光纤激光器的增益介质。     

钠蒸气参量四波混频紫外辐射的产生

记录并分析了钠原子蒸气形成近４Ｄ能级双光子共振参量四波混频产生的３３０ｎｍ信号，描述了信号强度随实验条件变化的规律，确定了最强辐射条件。