第五讲新型光纤水听器和矢量水听器

光纤水听器和矢量水听器作为当前水声研究领域最具有代表性的两大技术倍受业界关注。光纤水听器的重要贡献在于，从一个全新的角度出发，试图解决传统的水声传感和声纳数据传输一体化设计和实现的一系列问题，这有助于改善声纳系统的可靠性，并且有可能降低其制造、使用和维护的总成本。矢量水听器则由于其特有的指向性和矢量一相位处理方法，在低频和甚低频水声微弱目标探测方面具有潜在的优势．经过不懈的努力，光纤水听器和矢量水听器系统已经从实验室逐渐进入到工程应用阶段．这些对未来声纳系统的发展会产生相当重要的影响．文章尝试从声纳设计的角度对这两者的技术现状进行简要综述，包括它们各自的物理基础、工作原理、关键技术和应用领域．     

Preparation of Low-dielectric Permittivity Polyimide Resins with High Surface Activity from Chemically Bonded Hyperbranched Polysiloxane

Thermosetting resin matrix is the key component of advanced wave-transparent composites,where low dielectric constant,excellent processability,high thermal stability,as well as good bonding ability are required for resins.Herein,we prepared a series of phenylethynyl terminated polyimide(PI)resins by grafting amine-functionalized hyperbranched polysiloxane(HBPSi)to PI chains during the in situ polymerization.The effects of HBPSi on the processability of oligomers,molecular packing,thermal stability,dielectric property and bonding ability to reinforce Kevlar fibers of the cured PI/HBPSi composite resins have been examined in detail.The dielectric constants of the cured composite resins were greatly reduced from 3.29 to 2.19 without compromising its processability and thermal stability.Meanwhile,the 10 wt％HBPSi-containing PI resin demonstrated better bonding ability to reinforce fibers with the interfacial shear strength(IFSS)of 37.64 MPa,compared with that of neat PI-6 matrix(27.34 MPa),and better adhesion to metal with the lap shear strength of 10.48 MPa,50％higher than that of neat resin PI-6(6.98 MPa).These resultant PI/HBPSi composite resins exhibit excellent comprehensive properties,indicating their great potential as low-dielectric constant resin matrix in radar radome.     

Gluon saturation and net-proton spectra in relativistic nucleus-nucleus collisions

By means of the AKK08 fragmentation function, the net-proton transverse momentum (pT) spectra in A+A collisions are studied with two phenomenological models based on the Color Glass Condensate formalism. After a x2 analysis of the experimental data from BRAHMS, the normalization constant C is extracted at RHIC energies of √SNN =62.4 and 200 GeV, and the theoretical results of the net-proton pT spectra at selected rapidities are also given. It is shown that the theoretical results are in good agreement with the experimental data. Finally, assuming the constant C should have an exponent dependence of √SNN, we also predict the theoretical results of net-proton pT spectra at LHC energies of √SNN = 2.76, 3.94, and 5.52 TeV.     

Na1.0Zn1.62Si1.38O4.84·0.6H2O的水热合成及离子导电性质

Anew sodium zincosilicate single crystal Na_1.0Zn_1.62Si_1.38O_4.84·0.6H₂O with size of 0.3mm×0.3mm×0.3 mm was prepared by hydrothermal synthesis method. Powder X-ray diffraction analysis result shows that this compound is a new phase.The compound is stable up to 500℃. The results of ACimpedance measurement shows that its ionic conductivity at 450℃ is 2×10^-4S·cm^-1 and the activation energy for ionic conduction is 79.64 KJ/mol.     

高聚合度钨磷多金属氧酸盐的电化学性质和热稳定性

用循环伏安、热重及示差扫描量热法研究了高聚合度钨磷多金属氧酸盐的电化学性质和热稳定性,实验表明,标题化合物H16{[P4W14Na3（H2O）7O58]2[Na4（H2O）13]2[P4W14Na2（H2O）2O56]}·24H2O因其高聚合度而改变了单个阴离子的氧化还原性质,并且该化合物是一种热稳定性高的微孔材料。     

蒙成药如达多糖的研究

从蒙成药如达中提取水溶性多糖,硫酸-苯酚法测定其含量。平均回收率为99.8%,RSD为0.94%。GC测定了水溶性多糖的组成为葡萄糖、半乳糖和甘露糖。其摩尔比为:6.33:3.25:1.59。     

SrCeO3的微波合成及离子导电性质研究

ＳｒＣｅＯ_３的微波合成及离子导电性质研究徐秀廷，崔得良，冯守华，徐如人（吉林大学无机水热合成开放研究实验室，长春，１３００２３）关键词ＳｒＣｅＯ_３，微波合成，离子电导在复合氧化物中，ＳｒＣｅＯ３由于具有电子和离子混合导电性质而成为潜在的电极材料。另...     

含Ce的水热体系中结构稳定性及变价现象

利用ＸＲＤ、ＩＲ及ＸＰＳ谱研究了含Ｃｅ的水热体系中产物及其经过各种后处理的样品结构稳定性及Ｃｅ离子的价态变化。结果表明，不同的原料导致Ｃｅ离子稳定于不同的价态，如直接形成包括纳米晶在内的ＣｅＯ２及一新相ＣｅＯＨＣＯ３，样品ＣｅＯＨＣＯ３经２ＧＰａ的冷压处理未发生结构转变，经高温焙烧处理得到具有高结晶度的棕红色的ＣｅＯ２，当初始原料为Ｃｅ２（ＳＯ４）３和Ｃｅ（ＮＯ３）３时，产物为ＣｅＯ２；而当初始原     

辉光放电等离子体理论模型的建立 *

对已建立的辉光放电等离子体理论模型进行了改进,改进后的理论模型仍为自洽的解析式理论模型.对稍长放电间隙,不同工作气压条件下的电子密度分布进行了分析,并与实验结果进行了对照,说明了改进后的理论模型适用范围得到了扩大,与实验结果更为接近.     

脉冲抽运光啁啾对全光纤量子关联光子对纯度的影响

信号与闲置光子波长均为1550 nm 通信波段的全光纤关联光子对源, 具有低成本以及可与现有光纤网络低损耗连接的特点. 进一步优化其纯度, 将有助于提高这种量子光源的实用化程度.当抽运脉冲光在光纤中传输时, 由于色散和Kerr非线性效应的影响, 会不可避免地引入啁啾. 本文利用脉冲激光抽运零色散位移光纤, 研究了抽运光啁啾对关联光子对纯度的影响. 结果表明, 通信波段小失谐关联光子对的纯度随啁啾的增大而下降. 若采用变换极限的锁模激光为抽运源, 将有助于抑制Raman散射对自发四波混频的影响, 提高光子对的纯度. 关键词： 关联光子对 光纤 自发四波混频 啁啾