激光角度欺骗干扰半实物仿真研究

为有效评估激光角度欺骗干扰效果,搭建了一套激光角度欺骗干扰半实物仿真系统。仿真系统接入了导引头、惯组、弹载机、舵机等实物,采用实时通讯、姿态角精确模拟、视线角精确控制、多线程触发、加速度模拟注入等关键技术,提高了系统的实时性和仿真的可信度。以某典型激光制导武器为对象开展仿真研究,在设定的仿真条件下,无干扰时仿真的脱靶量为1.7 m,角度欺骗干扰时仿真的脱靶量为744.05 m,表明该系统能对激光角度欺骗干扰效果进行仿真评估,验证了制导控制系统和仿真系统软硬件设计的合理性。     

非平衡流动流射分光光度法在线测定痕量铅的研究

采用流动注射分析技术,研究了碱性介质中铅与ｍｅｓｏ－四－（４－三甲铵基苯）卟啉高灵敏的显色反应,用自制的微机化流动注射分析仪准确控制反应时间,利用非平衡法原则,优化了实验条件,建立了在线测定痕量铅的新方法。线性范围为０．００－２．００ｍｇ／Ｌ,分析速度每小时测定１２０次,方法适用于直接测定煤矿井水、鱼塘水、电场废水和自来水中的铅,所得的结果令人满意。     

CHARACTERIZATION OF MOLECULAR MASS OF SIX WATER-SOLUBLE POLYSACCHARIDE -PROTEIN COMPLEXES FROM GANODERMA TSUGAE MYCELIUM

Six water-soluble polysaccharide-protein complexes coded as GM1, GM2, GM3, GM4, GM5 and GM6 wereisolated from the mycelium of Ganoderma tsugae by extracting with 0.2 mol/L phosphate buffer solution at 25, 40 and80℃, water at 120℃, 0.5 mol/L aqueous NaOH solution at 25 and 65℃, consecutively. Their chemical components wereanalyzed by using IR, GC, HPLC and ~(13)C-NMR, and some new results were obtained. The four samples GM1, GM2, GM3and GM4 are heteropolysaccharide-prote in complexes, in which, α- (1→3) linked D-glucose is the major monosaccharidewhile galactose, mannose and ribose are the secondary ones. GM5 and GM6 are β-(1→3)-D-glucan-protein complexes. Theprotein content increased from 32% to 69% with the progress of isolation. Weight-average molecu1ar mass M_w and theintrinsic viscosity [η] of the GM samples in 0.5 mol/L aqueous NaCl solution at 25℃ were measured systematically by laserlight scartering (LLS), size exclusion chromatography (SEC) combined with LLS, and viscometry. The M_w of GM1 to GM6are 35.5, 46.8, 58.9, 41.6, 3.3 and 22.0×10~4, respectively. The conformation and molecular mass of the two fractions of sample GM5 were characterized satisfactorily by SEC-LLS without further fractionation.     

COMPARISON OF POLYSACCHARIDES ISOLATED FROM THE MYCELIA OF A CULTIVATED STRAIN OF PORIA COCOS GROWN IN DIFFERENT LIQUID CULTURE MEDIA

Mycelium of a cultivated strain of Poria cocos was grown by submerged fermentation in a liquid mediumcontaining corn steep liquor with orbital shaking. Six polysaccharides coded as ac-PCM1, ac-PCM2, ac-PCM3-Ⅰ andⅡ, ac-PCM4-Ⅰand Ⅱ were isolated from the myelium by extracting with 0.9% NaCl aqueous solution, hot water, 0.5 mol/L NaOHaqueous solution and 88% formic acid. Exo-polysaccharide was obtained from the culture medium and coded as ac-PCM0.The monosaccharide composition and molecular weights of these polysaccharides were characterized by using infraredspectroscopy, gas chromaography, elemental analysis, ~(13)C-NMR, viscometry and light scattering. The results indicated thatac-PCM0, ac-PCM1 and ac-PCM2 are heteropolysaccharides containing glucose, galactose, mannose and fucose, and ac-PCM3-Ⅰ and ac-PCM3-Ⅱ mainly consist of D-glucose. The content of the glucose in the polysaccharides increased with theisolation progress. Remarkably, α-glucan and β-glucan coexisted in the extract by NaOH aqueous solution (ac-PCM3), andcould be separated by chemical methods. The protein in the ac-PCM polysaccharides cultured from the medium containingcorn steep liquor was higher than that in the ab-PCM from the medium with bran extract. Therefore, the polysaccharidesfrom Poria cocos mycelia cultured in different media have different chemical composition, molecular weights and conformations.     

物联网感知层低能耗时间同步方法研究

针对物联网感知层对时间同步的需求及节点能量有限的特点,提出一种低能耗时间同步(Low EnergyConsumption Time Synchronization,LECTS)的方法,从同步消息量、同步周期和占空比角度研究同步能耗的降低.对网络进行父子群的划分,为每个群选择PS(Pairwise Synchronization)节点,群内节点持续同步,群间节点按需同步;父节点和PS节点间以同步周期和占空比双向交换N次同步消息,群内其他节点侦听同步消息,基于参数抵消的联合极大似然法估计子节点与父节点间的相位偏移和频率偏移,将群内子节点同步到父节点;在给定同步精度下,汇聚节点定期评估网络同步误差,由时间同步控制器调整网络同步周期和占空比.仿真结果表明LECTS算法在保证同步精度的同时,降低了同步能耗、提高了网络的生存周期.     

基于MC-UVE-VIP两步波长筛选实现近红外光谱模型的无标样传递

该文将蒙特卡洛-无变量信息消除(MC-UVE)算法和变量重要性投影(VIP)算法结合,挑选出重要、有信息的波长变量,建立了MC-UVE-VIP两步波长筛选方法。该法首先采用MC-UVE筛选出稳定性参数大于某一阈值(M_threshold)的有信息波长集合U_UVE,然后采用VIP算法从U_UVE中筛选出VIP参数大于U_UVE中所有波长VIP均值的波长,作为重要、有信息的波长集合U_UVE-VIP。基于U_UVE-VIP建立玉米中蛋白质含量的偏最小二乘回归(PLSR)近红外光谱预测模型,模型的潜变量个数根据累计贡献率大于99.9%确定。该模型变量少、稳健、可解释性强、运算速度快,其预测两台从机样品蛋白质的平均相对误差(MARE)分别为1.64%与1.88%,均小于MC-UVE模型的从机MARE(5.40%与5.19%)和VIP模型的从机MARE(6.23%与7.16%)。因此,基于MC-UVE-VIP两步波长筛选法所建立的玉米蛋白质含量近红外光谱模型可直接传递到从机,...     

双曲面摩擦摆支座典型桥梁的地震响应研究

为研究不同因素对粤东高烈度地区双曲面摩擦摆支座高速公路典型桥梁工程地震响应的影响,选取潮安韩江特大桥主桥(55+4×90+55)m为研究对象,该桥所有墩梁之间均采用双曲面摩擦摆支座。采用ANSYS有限元软件建立全桥模型,基于时程分析法研究了多种因素下桥梁结构的地震响应。研究表明,在纵桥向地震动激励下,桩土的相互作用对各桥墩墩底地震响应影响显著;栓钉全部剪断比栓钉全部不剪断的各桥墩墩底弯矩和剪力分布更均匀,桥墩上的固定支座栓钉不剪断将会增加该桥墩的弯矩、剪力以及支座剪力,但对其他桥墩的影响较小;该研究成果可应用于带栓钉的摩擦摆支座桥梁的地震响应分析。     

不同下垫面水平大气相干长度的测量与分析

与温度脉动仪测量结果对比验证了大气相干长度仪测量结果的可靠性,分析了两种仪器测量结果存在的差异及原因。对比大气相干长度仪测量的博贺海面、海边及合肥水平大气相干长度得出如下结论:全天海面水平大气相干长度最大,海边次之,合肥最小;合肥水平大气相干长度具有典型的日变化特征,清晨、傍晚转换时刻变化范围约4~10 cm、4~15 cm;海边水平大气相干长度清晨转换时刻变化范围约8~15 cm,特征与合肥相似,傍晚转换时刻后保持在12 cm左右;海面水平大气相干长度清晨转换时刻变化范围约9~12 cm,傍晚转换时刻约从15 cm迅速增至50 cm并保持2 h后迅速减至28 cm。结合不同下垫面的特点、天气状况及海陆风转换造成的影响,对上述实验结果进行了初步分析。     

LSTSVM的样本缩减与空间信息融合方法

针对最小二乘孪生支持向量机(STSVM,least squares twin support vector machines)分类效率低的不足,在一对余(1-a-r)多分类器的基础上,提出一种基于样本缩减(SR)的LSTSVM(SRLSTSVM)分类算法。在核空间中通过距离计算,选出对分类超平面起决定作用的样本点,用于分类器的训练;与此同时,为了充分利用高光谱遥感图像的空间信息,通过主成分分析(PCA)和二维Gabor滤波获取像元的纹理特征,将高光谱遥感图像的空间信息和光谱信息在图像层进行融合用于分类。实验证明,本文提出的SR算法可以在不影响分类精度的基础上大大提高LSTSVM的分类效率,且结合空间信息后的LSTSVM的总体分类精度也有明显提高。     

美国核武器实验室太赫兹技术与应用研究

超快激光技术、半导体技术以及电子技术的迅速发展为太赫兹波的产生提供了稳定、可靠的激发光源和探测器,从而使太赫兹科学技术的研究和应用得到了蓬勃发展,目前已成为国际上的研究热点。本文介绍了美国3大核武器实验室和美国重要国家实验室在太赫兹科学技术以及应用研究中开展的工作,并对其太赫兹技术的发展态势进行了分析。简单分析了太赫兹技术对武器物理研究的促进作用及其研究方向,例如：极端条件下材料的太赫兹表征与调控研究、含能材料化学反应动力学研究、冲击波与爆轰物理瞬态诊断研究等。