Audio steganalysis of spread spectrum information hiding based on statistical moment and distance metric

Audio information hiding has attracted more attentions recently. Spread spectrum (SS) technique has developed rapidly in this area due to the advantages of good robustness and immunity to noise attack. Accordingly detecting the SS hiding effectively and verifying the presence of the secrete message are important issues. In this paper we present two steganalysis algorithms for SS hiding. Both the two methods are based on machine learning theory and discrete wavelet transform (DWT). In the algorithm I, we introduce Gaussian mixture model (GMM) and generalize Gaussian distribution (GGD) to character the probability distribution of wavelet sub-band. Then the absolute probability distribution function (PDF) moment is extracted as feature vectors. In the algorithm II, we propose distance metric between GMM and GGD of wavelet sub-band to distinguish cover and stego audio. Four distance metrics (Kullback-Leibler Distance, Bhattacharyya Distance, Earth Mover’s Distance, L2 Distance) are calculated as feature vectors. The support vector machine (SVM) classifier is utilized for classification. The experiment results of both two proposed algorithms can achieve better detecting performance. Even when embedding strength gets 0.0005, the correct detection rate can reach up to 90%. Its simplicity and extensibility indicate further application in other audio steganalysis.     

黄蘑多糖对受X射线照射小鼠的防护作用

本文观察了预防给予黄蘑多糖对受Ｘ射线照射小鼠的保护作用及其对免疫功能的影响。结果表明，黄蘑多糖可明显提高受８．０ＧｙＸ线照射小鼠３０日存活率，保护指数可达１．７２，防护效果与人参多糖相近。另外，黄蘑多糖可显著增强受２．０Ｇｙ照射小鼠脾脏淋巴细胞产生ＩＬ－２和γＩＦＮ的能力，激活脾脏ＮＫ细胞，加速胸腺细胞周期进程。说明黄蘑多糖对受Ｘ线照射小鼠有一定的防护作用，可明显增强其免疫功能。     

BROAD-BAND VERTICAL INTERCONNECT BETWEEN MULTILAYER MODULES USING DOUBLE CURRENT PROBES

A novel vertical interconnect scheme between highly integrated multilayer low temperature co-fired ceramic (LTCC) modules has been proposed in this paper. Substrate integrated waveguide (SIW) is manufactured in LTCC substrate and microwave solder-less connector based on the fuzz button technology is used to realize reliable and effective interconnection. The proposed scheme makes use of double current probes to transfer energy between two substrates. Two forms of this interconnect are demonstrated, and simulated bandwidth more than 30% by using 15dB return-loss reference, insertion loss is less than 0.5dB over the passband.     

辐照纤维素材料结晶行为的研究

对电子束辐照处理后的滤纸、木屑和稻草三种纤维素材料的Ｘ衍射行为进行了较为系统的研究。结果可见，这三种植物纤维纱材料的相对结昌度都随辐照剂量的增加而减少，同时还发现它们的Ｘ衍射峰峰位都随照剂量增加小角方向位移，并呈线性关系，实验还发现木屑所含大量木质素并没有在电子束辐射照场中对纤维素晶区起保护作用     

孔隙水压力计埋设过程中的问题研究

孔隙水压力计在实际使用过程中,通常不能按照规范那样进行现场标定,现场常采用无套管钻孔埋设孔隙水压力计,从而可能会影响孔隙水压力计精度,且在实际使用过程中量程选择也是一个难题.针对这种情形,通过分析常压标定方式误差、量程选择问题及无套管埋设孔隙水压力计,得出采用的现场常压标定及无套管埋设是可行的.     

Selective Capture and Quick Detection of Targeting Cells with SERS‐Coding Microsphere Suspension Chip

Circulating tumor cells (CTCs) captured from blood fluid represent recurrent cancers and metastatic lesions to monitor the situation of cancers. We develop surface‐enhanced Raman scattering (SERS)‐coding microsphere suspension chip as a new strategy for fast and efficient capture, recovery, and detection of targeting cancer cells. Using HeLa cells as model CTCs, we first utilize folate as a recognition molecule to be immobilized in magnetic composite microspheres for capturing HeLa cells and attaining high capturing efficacy (up to 95%). After capturing cells, the composite microsphere, which utilizes a disulfide bond as crosslinker in the polymer shell and as a spacer for linking folate, can recycle 90% cells within 20 min eluted by glutathion solution. Taking advantage of the SERS with fingerprint features, we characterize captured/recovered cells with the unique signal of report‐molecule 4‐aminothiophenol through introducing the SERS‐coding microsphere suspension chip to CTCs. Finally, the exploratory experiment of sieving cells shows that the magnetic composite microspheres can selectively capture the HeLa cells from samples of mixed cells, indicating that these magnetic composite microspheres have potential in real blood samples for capturing CTCs.     

Heavy metals in urban soils with various types of land use in Beijing, China

Heavy metal concentrations of Cd, Cr, Cu, Ni, Pb and Zn were investigated for 127 urban soil samples collected from business area (BA), classical garden (CG), culture and education area (CEA), public green space (PGS), residential area (RA) and roadside area (RSA) in Beijing. The distribution of Cd, Cu, Pb and Zn was mainly affected by anthropogenic sources, with their mean concentrations much higher than the background values of Beijing, while Cr and Ni were from natural sources. Among the 6 types of land use, the concentrations of Cd, Cu, Pb and Zn in CG were significantly higher than those in the other 5 types of land use (p<0.05), which were due to their historical use such as pigments, wood preservation and brassware. For the other 5 types of land use except CG, the mean concentration of Cd in RSA was significantly higher than those in BA, CEA, PGS and RA (p<0.05), suggesting Cd was mainly from traffic sources. The distribution maps revealed that the concentrations of Cu, Pb and Zn showed decreasing trends from the center to the suburb of Beijing, they increased with the age of the urban area.     

川东地区高陡构造VTK垂直钻井配套钻井液技术

针对川东地区高陡构造高地层倾角井井眼轨迹控制难度大,并且上部自流井群泥页岩极易发生垮塌等特点,提出应用VTK(VertiTrak)垂直钻井技术防斜打快,并配合使用活度平衡防塌钻井液,以确保井眼稳定和VTK设备安全.介绍了钻井液体系的选择思路和配方的优选.天东004-X3和板东006-H1两口试验井通过应用该技术,平均机械钻速比邻井相同层位提高了57.1％以上,钻井周期缩短了6.1 d,表明VTK垂直钻井技术在高陡构造高倾角井和易斜地层能有效控制井斜,实现直井段的防斜打快、提高机械钻速,配套的活度平衡防塌钻井液具有“强抑制、平衡滤液活度、超低渗透”特性,能有效解决易塌泥页岩地层的井眼稳定问题,并成功实现化学防塌,较大幅度地降低了钻井液密度.     

硅太阳电池稳步走向薄膜化

考察了硅太阳电池在光伏产业中所处的地位,分析了薄膜硅太阳电池的发展趋势。指出硅太阳电池在未来15a仍将保持优势地位,并继续沿着晶硅电池和薄膜硅电池两个方向发展。在此发展过程中,两个发展方向的主流很可能会汇合到一起,共同促使低成本、高效率、高可靠薄膜晶硅电池的诞生和产业化,从而继续保持硅太阳电池的优势地位。     

Application of photonic crystal enhanced fluorescence to cancer biomarker microarrays

We report on the use of photonic crystal surfaces as a high-sensitivity platform for detection of a panel of cancer biomarkers in a protein microarray format. The photonic crystal surface is designed to provide an optical resonance at the excitation wavelength of cyanine-5 (Cy5), thus providing an increase in fluorescent intensity for Cy5-labeled analytes measured with a confocal microarray scanner, compared to a glass surface. The sandwich enzyme-linked immunosorbent assay (ELISA) is undertaken on a microarray platform to undertake a simultaneous, multiplex analysis of 24 antigens on a single chip. Our results show that the resonant excitation effect increases the signal-to-noise ratio by 3.8- to 6.6-fold, resulting in a decrease in detection limits of 6-89%, with the exact enhancement dependent upon the antibody-antigen interaction. Dose-response characterization of the photonic crystal antibody microarrays shows the capability to detect common cancer biomarkers in the <2 pg/mL concentration range within a mixed sample.