YAG晶体是一种典型硬脆材料,莫氏硬度达8.5,常温下不溶于任何酸碱,加工难度较大.针对YAG晶体研磨加工,本工作提出一种分步研磨工艺.基于游离磨料研磨的方法,在研磨过程中逐级减小碳化硼(B4C)磨料粒径,选用磨料W40、磨料W28、磨料W14、磨料W7分步骤研磨,4种磨料的粒度范围依次为:40～28μm、28～20μm、14～10μm、7～5μm.通过研磨参数试验研究了每个步骤中研磨压力、研磨盘和摆轴转速、研磨液中B4C质量分数等参数对研磨效果的影响,得出最佳研磨参数;通过截面显微法测量出YAG晶体研磨后亚表面损伤的深度,确定后续抛光去除量,并探究了亚表面损伤深度hSSD与研磨后表面粗糙度Ra的关系.研究表明:当研磨压力为44.54 kPa、研磨盘和摆轴转速为60 r/min、研磨液中B4C质量分数为15％时,每个研磨步骤均取得最好研磨效果:磨料W40、磨料W28、磨料W14、磨料W7研磨的材料去除率分别为83.12、57.32、27.54、9.53μm/min,研磨后表面粗糙度Ra分别为0.763、0.489、0.264、0.142μm.截面显微法测量得出分步研磨后产生的亚表面损伤深度为3.041μm,需要在后续抛光中去除;此研磨参数下YAG晶体研磨后亚表面损伤深度与表面粗糙度的关系为:hSSD=41.46×Ra4/3,该研究可为YAG晶体元件的实际加工生产提供指导.

为了提高滚动轴承故障诊断的准确率,提出一种基于主成分分析(principal component analysis,PCA)和支持向量机(support Vector machine,SVM)模型的滚动轴承故障诊断方法.通过比较不同方法计算的标准差和拉依达准则对数据进行误差分析,利用MATLAB软件中的PCA函数对数据进行主成分分析,将8个原始变量降维成3个综合变量,分别从降维前和降维后的输入属性数据中随机选取70％的数据作为训练集来建立SVM分类模型和PCA-SVM分类模型,而把剩余的30％作为测试集来对模型的性能进行仿真测试.MATLAB仿真测试的结果表明,PCA-SVM模型的分类效果更好,其预测正确率对于绝大多数故障诊断来说是可以接受的,可以作为一种故障诊断的评价标准.

机载合成孔径雷达硬件架构和成像算法的不断发展对复杂大尺度目标的实时回波仿真提出了更高要求.为了实现雷达仿真器实时和多模式性能的提升,基于Xilinx可编程逻辑SoC平台ZYNQ设计了机载合成孔径雷达实时回波仿真器,将改进二维快速傅里叶变换的回波仿真算法与具体硬件实现流程结合,提出了基于AXI总线PS-PL互联的脚本式CORDIC回波仿真方法,实现了复杂面目标回波的实时仿真.对于雷达目标模型高精度仿真算法研究,高性能便携式实验室回波仿真器研制,以及多模式回波仿真方法与高性能硬件平台的结合具有重要的实践参考意义.通过对比计算机仿真结果与仿真器实验室测试结果,证明了基于上述方法的机载合成孔径雷达回波仿真器的高效性和完整性.

近年来,形状记忆合金(shape memory alloy,SMA)由于噪声小、回复应变大和生物兼容性好等优点,得到了广泛的使用和研究.为了研究SMA在软体机器人领域的应用,首先对SMA在国内外的研究现状进行了分析,接着对SMA的形状记忆效应(shape memory effect,SME)、超弹性、电阻特性进行了阐述,最后介绍了SMA在软体机器人领域的应用现状.

Synthetic aperture radar (SAR) systems produce large amounts of data which needs to be compressed and transferred.SPIHT compression algorithm performance superior,but the coded images have fragile visual quality when transmitted across the noisy channel.An error-tolerance mechanism is necessary.An error-resilience algorithm called LL coefficients hiding (LLCH) for transmission of synthetic aperture radar (SAR) amplitude compression images in noisy channel is presented.The proposed method partitions data based on the coding process after the set partitioning in hierarchical tree (SPIHT's) coding process,to ensure that the decoder can re-synchronize after the error occurs.The most significant low frequency and sub-low frequency coefficients are embedded into the end of high frequency data packets to achieve the purpose of protecting the important coefficients.For the high frequency coefficients of damage or loss,linear interpolation is used to recover the coefficients rely on the correlation between subbands.The experimental results show that the algorithm can effectively improve the quality of the restored image under the tiny redundancy cost.

Three methods,the trapezoidal rule,the straight lines on log-log plots of area versus thickness and the straight lines on plots of log thickness versus square root of area,of calculating volumes of fallout tephra deposited in Sihai Phase of Jinlongdingzi Volcano of Longgang Volcanic Swarm in Jilin Province are applied in this paper.The calculated results are 0.096km~3,0.138km~3 and 0.1095km~3 respectively.Contrasting with the result(0.105km~3) of volcalic eruption program by Los Alamos National Laboratory,the last method is considered the best calculation,and the problems of the other two methods are discussed.The method using straight lines on plots of log thickness versus square root of area is recognized to be relatively reasonable because volcanic deposits decrease exponentially with distance from volcano center.

Longgang volcanic swarm belongs to one of volcanic areas which have been active since modem times. In view of multiple eruptions during histories, it is very important to determine age of every eruption for evaluating volcanic hazards. The alkaline basalt samples taken from Dayizishan and Diaoshuihu are analyzed by U-series component method, after magnetic separation. The ages of the two samples are (71 +/- 9) ka, (106 +/- 13) ka before presence, respectively. These data indicate that there exist intensively eruptive activities during late Pleistocene.

INAA analysis is considered as an effective method to study the geochemical features of some tiny minerals which are very difficult to be selected from rock samples. Both rare earth elements and trace elements in the rock-forming minerals of the granite from Jiangxi Province, including potash feldspar, plagioclase, quartz, biotite, accessory minerals, zircon and apatite, were analyzed and studied by INAA.Measured data show that the total 8 REE contents of minerals gradually decrease from zircon, apatite, biotite, plagioclase, potash feldspar to quartz in proper order, indicating a crystallization process of the granite. The Eu abnormal of whole rock would be affected by biotite, potash feldspar and plagioclase.

以新疆西准噶尔玛依拉山-萨雷诺海蛇绿岩为重点进行讨论.该区出露的火成岩种类较多,表现出构造混杂特点.变质橄榄岩是具有一定亏损程度的地幔残体,LREE的富集主要是后期蚀变的结果.玄武岩的稀土分布型式是平坦型的或LREE略亏损型的.与MORB相比,REE的总量较高,高Fe和Ti,Mg值低,是一种演化的岩石,与东太平洋中隆地高Fe和Ti的铁质拉斑玄武岩成分相当,地球化学特征类似于MORB,可能形成于小洋盆环境.

The enstenite and its melt inclusions picked up from mantle xenoliths at Longgang volcanoes in Jilin province are measured by synchrotron radiation X-ray microprobe techniques. Some element contents, such as K, Sc, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Sr, Y are calibrated by NIST SRM 612. The relative deviations of element contents analyzed in enstenit between X-ray fluorescence microprobe and wavelength dispersive electron beam microprobe are 15%, 5% 7% and 8% for Cr, Mn, Fe, Ni, respectively. Chondrite normalized transition metal elements distribution pattern of inclusion is similar to that of whole rock analyzed by INAA, which implies that primitive magma experienced partial melting or segregation during ascending.

According to the analysis by U-series component method,Dayizishan volcano erupted at 71±9 ka B P in late Pleistocene. Petrochemical and geochemical features of the eruption products of all phases imply that they came from the same magma resource. Based on petrological methods and the degassing model devised by Thordarson in 1996,It is estimated from the measured chlorine and fluorine concentrations in the samples that the atmospheric loading of hydrochloric acid and that of hydrofluoric acid were 7.36 Mt and 5.21 Mt,respectively.

A total of 28 old Jun porcelain, seven modern Chinese Jun porcelain and two Jingdezhen porcelain samples are analyzed with INAA method. The systematic geochemical study for these 37 samples on their REE and trace elements shows that these three types of china were made with relatively stable and similar material, although they leaptover 600 years in different colors and from different kilns. However, the REE patterns of modern Chinese Jun porcelain are a little bit different from that of old Jun porcelain, and clear different from the old glaze of Jindezheng.

用预浓集中子活化法测定了达拉布特蛇绿岩中超镁铁质岩中的稀土元素(REE),用仪器中子活化法测定了其中的过渡金属元素.依据测定结果分析了过渡金属及REE的地球化学特征.认为,二辉橄榄岩X12可能代表原始地幔的化学成分;二辉橄榄岩X10,X11和含矿的纯橄岩X17,方辉橄榄岩X18为上地幔经历了部分熔融后残留的地幔物质;不含矿的纯橄岩X8和异剥橄榄岩X7,X9为自镁铁质熔融体在上地幔内以堆晶作用形成的超镁铁质岩类.

讨论了合成孔径雷达(SAR)距离向数字脉冲压缩的原理和实时实现技术.以TMS320C6701和APEX20K系列EPLD为例,叙述了针对不同SAR系统参数的频域和时域的实现方案.其中包括快速卷积重叠保留法的TI DSP实现,以蝶形运算核实现FFT为主要技术的EPLD实现等频域实现方式,以及采用卷积型FIR结构实现时域匹配滤波的方法及各种方案的适用性.

用色差仪测量汝瓷釉面的特征光谱和主波长, 确定了汝瓷釉色和主波长之间的关系; 用中子活化分析(NAA)测量汝瓷釉中30种着色元素含量, 确定了铁是主着色元素; 用Mossbauer谱确定了釉层中的铁是以结构铁的形式(Fe2+, Fe3+)存在, 测定了各种颜色釉面的特征光谱的主波长与结构铁浓度(Fe2+ /Fe3+)之间的定量关系; 探讨了汝瓷的着色机理.

用色差仪测量了各种颜色汝瓷釉面的反射光谱,用Mssbauer谱测定了釉中结构铁(Fe2+,Fe3+)的相对含量和各种釉色的主波长之间的定量关系.探讨了汝瓷的呈色机理和烧制技术.研究表明,天青汝瓷是在重还原气氛中和高温条件下烧成的,粉青汝瓷是在中等还原气氛中和稍低温度条件下烧成的,豆绿汝瓷是在轻还原气氛中和较低温度条件下烧成的.

我们利用自行开发的ADSP21062信号处理板结合多极化合成孔径雷达数据流的特点,采用并行处理方式,实现了一种多极化雷达原始数据的压缩算法.

The theory of non-linear compression of SAR raw data,the design of two-dimensional non-linear compression scheme and it's realization of hardware are discussed.

介绍一种具体的模糊聚类分析数学模型和程序设计方法,对古钧瓷胎和釉的36种微量元素进行了分析,得到了古钧瓷胎和釉的原料产地和分类的信息.

Trace－elements in ancient ceramics and imitative ancient ceramics were determined by neutron activation analysis (NAA). The NAA data are then analyzed by fuzzy cluster method and the trend cluster diagram is obtained. The raw material sources of ancient ceramics and imitative ancient ceramics are determined. The path for improving quality of imitative ancient ceramics is found.