分组M元扩频Pattern时延差编码水声通信

针对水声通信中通信速率和频带利用率不高的问题,提出将M元扩频技术与Pattern时延差编码相结合,将多进制扩频码作为Pattern波形进行时延差信息调制,在接收端利用拷贝相关器解出信息,提高了系统的通信速率和抗干扰能力;在此基础上又提出了分组扩频的概念,对发送端扩频码进行有效分组,利用其良好的正交性,将各组挑选出的扩频码并行传输,进一步改善系统的通信速率和频带利用率.在信道水池内进行了通信实验,在2.5 kHz带宽内,M元扩频PDS系统通信速率为91 bit/s,分组M元扩频PDS系统可达302bit/s,误码率为1×10-4,实验结果验证了该系统的可行性和鲁棒性.

论云冈第13窟窟顶图像的来源与传播

云冈第13窟窟顶图像由依附于主尊身光上方的弧状纹样带与两条交缠的龙组成。窟顶依附于主尊身光上缘的弧状纹样带,最早可追溯至犍陀罗、秣菟罗地区佛教造像中尊像身后的树木,被称为“华盖式圣树”。此窟窟顶纹样带内部忍冬枝藤所结果实或代表了兜率天中“果如颇黎色”的七宝行树,与同样位于窟顶的交龙(或为护树、为树布雨的龙王)共同构成了兜率天胜景。豫北北魏背屏式造像侧面纹饰及龙门石窟北魏晚期圆楣龛圆楣、部分造像龛主尊内层身光顶部的忍冬纹都与云冈第13窟窟顶图像存在不同程度的亲缘关系。

带夹装置在高精度刺绣中的应用与性能优化

高精度刺绣在现代纺织工业中占据重要地位,但传统带夹装置难以精确调节夹持力,导致绣带移位和刺绣质量下降。文章提出了一种新型带夹装置,通过改进结构和功能,提升刺绣精度和生产效率。该装置利用压簧和螺帽的调节机制,实现绣带的良好固定和夹持力的精确调节,适用于不同厚度和材质的绣带。实验结果表明,使用新型带夹装置后,刺绣精度、绣带稳定性、生产效率、操作便捷性等指标均显著优于未使用装置的情况,减少了图案偏移和失真,提升了整体质量。性能优化措施包括选择高强度材料、改进结构设计和定期维护,延长了装置的使用寿命,提高了装置的工作效率,对提升纺织工业技术水平和产品质量具有重要意义。

Narrow-band imaging with magnifying endoscopy for the evaluation of gastrointestinal lesions

Narrow band imaging(NBI) endoscopy is an optical image enhancing technology that allows a detailed inspection of vascular and mucosal patterns, providing the ability to predict histology during real-time endoscopy. By combining NBI with magnification endoscopy(NBI-ME), the accurate assessment of lesions in the gastrointestinal tract can be achieved, as well as the early detection of neoplasia by emphasizing neovascularization. Promising results of the method in the diagnosis of premalignant and malignant lesions of gastrointestinal tract have been reported in clinical studies. The usefulness of NBI-ME as an adjunct to endoscopic therapy in clinical practice, the potential to improve diagnostic accuracy, surveillance strategies and cost-saving strategies based on this method are summarized in this review. Various classification systems of mucosal and vascular patterns used to differentiate preneoplastic and neoplastic lesions have been reviewed. We concluded that the clinical applicability of NBI-ME has increased, but standardization of endoscopic criteria and classification systems, validation in randomized multicenter trials and training programs to improve the diagnostic performance are all needed before the widespread acceptance of the method in routine practice. However, published data regarding the usefulness of NBI endoscopy are relevant in order to recommend the method as a reliable tool in diagnostic and therapy, even for less experienced endoscopists.

Using the Maximum Effective Moment Criterion to Interpret Quartz -Fabric Patterns

The Maximum Effective Moment(MEM)criterion predicts that the initial orientation of ductile shear zones and shear bands is^55°relative to the maximum principal stress axis(σ1)and that the kinematic vorticity number(Wk)is^0.94.These preferred orientations should be reflected in the pattern of quartz<c>-fabrics in shear zones and shear bands.Common quartz<c>-fabrics in plane strain can be divided into low-temperature(L)and high-temperature(H)fabrics,with each group showing three patterns.A steady flow with a constant value of Wk≈0.94 gives rise to L-1 and H-1 patterns,which are commonly characterized by a single<c>axis girdle normal to the shear zone and a single<c>-point maximum parallel to the shear zone.Once the conjugate set develops,L-1 and H-1 have opening angles of^70°and^110°,respectively.L-2 and H-2 are asymmetric patterns associated with variable deformation partitioning and vorticity values of0<Wk<0.94.In contrast,L-3 and H-3 are symmetric patterns associated with 100%deformation partitioning and Wk=0.The opening angle in quartz<c>-fabrics is implicitly linked to the temperature during deformation.The opening angle is^70°at low temperature and^110°at high temperature.However,a linear correction between the opening angle and the temperature cannot be established.During deformation partitioning,synthetic shear bands form earlier than antithetic bands and are more easily developed.This may result in opening angles of<70°for low-temperature fabrics and of>110°for high-temperature fabrics.The following criteria can be used to recognize reworked shear zones that have experienced multiple orogenic phases and changes in the stress state:1)the initial Wk is larger or smaller than^0.94;2)the change in Wk is abrupt,rather than progressive;3)inconsistent shear senses are inferred for the different phases of deformation;and4)a negative value of Wk is found in reworked shear zones.

Analysis of dynamic of two-phase flow in small channel based on phase space reconstruction combined with data reduction sub-frequency band wavelet

A new method of nonlinear analysis is established by combining phase space reconstruction and data reduction sub-frequency band wavelet. This method is applied to two types of chaotic dynamic systems(Lorenz and Rssler) to examine the anti-noise ability for complex systems. Results show that the nonlinear dynamic system analysis method resists noise and reveals the internal dynamics of a weak signal from noise pollution. On this basis, the vertical upward gas–liquid two-phase flow in a 2 mm × 0.81 mm small rectangular channel is investigated. The frequency and energy distributions of the main oscillation mode are revealed by analyzing the time–frequency spectra of the pressure signals of different flow patterns. The positive power spectral density of singular-value frequency entropy and the damping ratio are extracted to characterize the evolution of flow patterns and achieve accurate recognition of different vertical upward gas–liquid flow patterns(bubbly flow:100%, slug flow: 92%, churn flow: 96%, annular flow: 100%). The proposed analysis method will enrich the dynamics theory of multi-phase flow in small channel.

Prediction of colorectal tumor grade and invasion depth through narrow-band imaging scoring

AIM To determine the usefulness of assigning narrow-band imaging(NBI) scores for predicting tumor grade and invasion depth in colorectal tumors.METHODS A total of 161 colorectal lesions were analyzed from138 patients who underwent endoscopic or surgical resection after conventional colonoscopy and magnifying endoscopy with NBI. The relationships between the surface and vascular patterns of the lesions, as visualized with NBI, and the tumor grade and depth of submucosa(SM) invasion were determined histopathologically.Scores were assigned to distinct features of the surface microstructures of tubular and papillary-type lesions.Using a multivariate analysis, a model was developed for predicting the tumor grade and depth of invasion based on NBI-finding scores.RESULTS NBI findings that correlated with a high tumor grade were associated with the "regular/irregular"(P < 0.0001)surface patterns and the "avascular area" pattern(P =0.0600). The vascular patterns of "disrupted vessels"(P = 0.0714) and "thick vessels"(P = 0.0133) but none of the surface patterns were associated with a depth of invasion of ≥ 1000 μm. In our model, a total NBIfinding score ≥ 1 was indicative of a high tumor grade(sensitivity: 0.97; specificity: 0.24), and a total NBIfinding score ≥ 9(sensitivity: 0.56; specificity: 1.0) was predictive of a SM invasion depth ≥ 1000 μm. Scores less than these cutoff values signified adenomas and a SM invasion depth < 1000 μm, respectively. Associations were also noted between selected NBI findings and tumor tissue architecture and histopathology.CONCLUSION Our multivariate statistical model for predicting tumor grades and invasion depths from NBI-finding scores may help standardize the diagnosis of colorectal lesions and inform therapeutic strategies.

A flexible ultra-broadband metamaterial absorber working on whole K-bands with polarization-insensitive and wide-angle stability

For potential military applications, a flexible metamaterial absorber(MMA) working on whole K-bands with totalthickness of 3.367 mm, ultra-broadband, polarization-insensitive, and wide-angle stability is presented based on frequencyselective surface(FSS). The absorber is composed of polyvinyl chloride(PVC) layer, polyimide(PI) layer, and poly tetra fluoro ethylene(PTFE) layer, with a sandwich structure of PVC–PI–PTFE–metal plate. Periodic conductive patterns play a crucial role in the absorber, and in traditional, it is designed on the upper surface of PI layer to form LC resonance. Different from commonly absorber, all the patterns are located on the lower surface of the PI layer in this work, and hence the impedance matching and absorptivity are improved in this purposed absorber. The flexible absorber with patterns on lower surface of the PI layer is compared with that on upper surface of the PI layer, the difference and the reasons are explained by absorption mechanism based on equivalent circuit model, and surface current density and electric field distribution are used to analyze resonance peaks. Absorptivity is greater than 90% in a frequency range of 10.47 GHz–45.44 GHz with relative bandwidth of 125.1%, covering the whole Ku, K, Ka, and some of X, U bands, especially containing the whole K bands from 12 GHz to 40 GHz. Radar cross section(RCS) is reduced at least 10 dB in 11.48 GHz–43.87 GHz frequency ranges,and absorption remained about 90% when the incident angle changed from 0°to 55°. The purposed absorber is fabricated,measured, and experiment results show good agreement with theoretical analysis and numerical simulation. After bonded on outer surface of different cylinders with diameters of 200 mm and 100 mm, the absorption of MMA is approximately reduced 10% and 20% respectively, which shows good conformal character with surface of various curvatures. Due to the attractive performance on strong absorption in the whole K-bands, flexible and easy conformal, our design exhibits broad potential application in radar stealth and sensors.

Na Induced Changes in the Electronic Band Structure of Graphene Grown on C-Face SiC

Studies of the effects induced on the electron band structure after Na deposition, and subsequent heating, on a C-face 2 MLs graphene sample are reported. Na deposition shifts the Dirac point downwards from the Fermi level by about 0.5 eV due to electron doping. After heating at temperatures from around 120℃ to 300℃,thep-band appears considerably broadened. Collected Si 2p and Na 2p spectra then indicate Na intercalation in between the graphene layers and at the graphene SiC interface. The broadening is therefore interpreted to arise from the presence of two slightly shifted, but not clearly resolved,p-bands. Constant energy photoelectron distribution patterns, E(kx,ky);s, extracted from the clean 2MLs graphene C-face sample look very similar to earlier calculated distribution patterns for monolayer, but not Bernal stacked bilayer, graphene. After Na deposition the patterns extracted at energies below the Dirac point appear very similar so the doping had no pronounced effect on the shape or intensity distribution. At energies above the Dirac point the extracted angular distribution patterns show the flipped, “mirrored”, intensity distribution predicted for monolayer graphene at these energies. An additional weaker outer band is also discernable at energies above the Dirac point, which presumably is induced by the deposited Na.

Multi-Band Antenna with Three Folded Monopoles for Mobile Communication Systems

This paper presents the design and the experimental characterization of a new multi-band antenna consisting of three folded monopoles dedicated to mobile communication systems. The originality of this paper is to get the PMR (Professional or Private Mobile Radio) band with the GSM (Global System for Mobile Communications), DCS (Digital Cellular System) and UMTS (Universal Mobile Telecommunications System) bands. The main lobe of the antenna radiates in the zenith direction with a linear polarization over all bands. It is interesting to design the proposed antenna in order to obtain better performances in terms of directive radiation pattern (especially in the PMR band) in comparison with the already existing antenna systems in the wireless market for similar purposes. The prototype was studied with the software CST-MWS (Micro wave studio 2012). The antenna has been designed and successfully measured.

W波段宽带宽角低副瓣类喇叭天线稀布阵

针对大损耗、制作工艺、T/R组件尺寸与通道数量以及位置等因素带来的W波段宽带宽角低副瓣相控阵天线设计难题,文中设计了一款在80~110 GHz频率范围内的宽带类喇叭天线单元,天线驻波比均小于1.8。在充分考虑T/R组件带来的布阵空间限制下,文中仅通过阵元位置优化设计了64元高增益低副瓣宽带宽角阵列天线,并为该阵列设计了小型低剖面空气波导馈电网络。仿真结果表明,64元稀布阵在䥺SymbolqB@40°波束扫描范围内下增益高于22.6 dB,副瓣电平低于-6.2 dB,各阵元有源驻波比均小于2,证实该阵列天线具有宽带宽角、低副瓣、高增益、结构易于加工实现等优点,应用前景良好。

2020—2022年江苏省某VCT门诊新发现HIV感染者首次CD^(+)_(4)T计数和WB带型关系

目的探讨CD^(+)_(4)T淋巴细胞(CD4)计数和WB带型的关系。方法选取2020—2022年江苏省某VCT门诊新发现的HIV感染者309例,采用流式细胞仪进行CD4检测,全自动免疫印迹仪测定WB。结果江苏省309例新发现HIV感染者以大专及以上学历、年龄<40岁未婚男男性行为人群为主,且存在晚发现情况。CD4计数<200个/μL 41例(占13.5%),200~<350个/μL 91例(占30.0%),350~<500个/μL 97例(占32.0%),≥500个/μL 80例(占26.4%)。WB带型检测结果显示,全带型、缺失p55、缺失p55+p39、缺失p55+p39+p17的带型是4个主要带型,分别占22.3%、22.0%、19.7%、11.0%,全带型检出率随着CD4计数的增加而提高(χ^(2)_(趋势)=11.59,P<0.05)。不同CD4计数水平感染者的各抗体条带检出率,仅p55的检出率在不同水平间的差异有统计学意义(χ^(2)=12.37,P<0.05),且随着细胞计数的增加而增高。结论新发现HIV感染者首次CD4计数<200个/μL的人群中,全带型检出率低于其余各组;p55的出现率会随着机体免疫力的下降而降低;缺p55、缺p55+p39人群可能疾病进展较快,需要尽早抗病毒治疗。

华南虎染色体核型分析及带型模式建立研究

采用外周血淋巴细胞培养及G带染色体标本制作技术,研究和分析华南虎(Panthera tigris amoyensis)染色体的核型和带型。结果表明:华南虎二倍体染色体数为2n=38条,其中常染色体18对,性染色体1对。常染色体按相对长度从长到短依次编号为1~18。根据着丝粒指数可将华南虎染色体分为4组,即A组(m),包括2、5、13、18和X;B组(Sm),包括1、4、7、8、9、10、11、12、14、17和Y;C组(St),包括3、6;D组(t),包括15、16。核型公式为8(m)+20(Sm)+4(St)+4(t),XY(m,Sm)/XX(m,m)。本研究成功制备了华南虎染色体核型标本,初步建立了华南虎染色体G带核型模式图谱。经比对,发现华南虎与东北虎(P. t. altaica)染色体核型存在明显差异,可为虎亚种的分类研究提供依据,同时能为华南虎种群基因多样性及遗传学研究提供新的参考和开辟新的途径。

华南虎染色体带型分析

为保护华南虎Panthera tigris amoyensis物种,以静脉血淋巴细胞G显带和R显带染色技术研究和分析华南虎染色体带型。结果显示,华南虎每条染色体具有独特的带型特征,常染色体中带数最多的为24条带,带数最少的为6条带;性染色体中X染色体为12条带,Y染色体是相对长度最短也是带数最少的染色体,仅3条带。实验成功制备华南虎染色体G带和R带标本,得到248条带的华南虎染色体分带模式,经初步对比发现华南虎染色体G带模式虽与家猫染色体分带高度近似,但也存在少部分明显区别,研究华南虎染色体带型有利于虎及其它猫科动物的遗传学和基因多样性方面研究。

基于特征优化的无参考光场图像质量评价

光场图像因其能够捕捉光的方向信息而备受学术界和产业界的广泛关注,然而,光场图像在压缩和重建过程中常会出现不同程度的失真,影响光场图像的后续处理和应用。因此,需要设计一个光场图像质量评估器来估计失真光场图像的质量。传统的光场图像评价方法在提取光场图像的空间特征和角度特征时,未充分考虑人眼视觉的多通道特性以及人眼对角度变化的敏感性,从而影响光场图像的质量评价结果。为此,提出一种无参考光场图像质量评价方法。设计多频带局部二值模式算法,提取光场图像的空间特征并利用优化提取的空间特征测量光场图像的空间质量。提出加权局部相位量化算法,该算法在对微透镜图像单元中提取的角度特征进行相位量化时,根据角度信息变化的强弱赋予不同的权值。在此基础上,将空间和角度纹理特征结合成一维特征向量,输入到已经训练的支持向量回归中,得到光场图像的质量分数。在Win5-LID和NBU-LF1.0数据集上的实验结果表明,该方法的斯皮尔曼等级相关系数分别为0.799 1和0.803 2,相比SSIM、FSIM、BRISQUE等方法,具有更优的质量评估准确性和稳定性。

泰和乌骨鸡的核型与带型研究

采用外周血淋巴细胞培养——空气干燥法,对泰和乌骨鸡染色体核型和带型进行了研究。结果表明:泰和乌骨鸡体细胞染色体数目2n=78,染色体基本臂数AF=90,1、9号染色体及Z、W性染色体为中央着丝粒(m)染色体,2、4、7号染色体为亚中央着丝粒(sm)染色体,3、6、8、10号染色体为端着丝粒(t)染色体。G带研究表明:前10对大型染色体可分为29个区,190条带。C带处理发现,所有母鸡分裂相中W性染色体都出现C带并整条深染。Ag-NORs研究发现:Ag-NORs常定位于1、2号常染色体短臂和Z性染色体短臂端部;Ag-NORs数目分布范围为1～6;平均每个细胞的Ag-NORs数在雌、雄鸡中分别为2.94和2.96。

新麦草属两物种的C-分带研究

对新麦草属（Ｐｓａｔｈｙｒｏｓｔａｃｈｙｓ）两物种新麦草（Ｐｓａｔｈｙｒｏｓｔａｃｈｙｓｊｕｎｃｅａ）和华山新麦草（Ｐｓａｔｈｙｒｏｓｔａｃｈｙｓｈｕａｓｈａｎｉｃａ）进行根尖染色体Ｃ－分带，获得清晰的Ｃ－分带带型，并对二者带型进行了描述。结果表明，二者Ｃ－分带带型有较大差异。Ｐ．ｊｕｎｃｅａ的Ｃ－分带带纹较Ｐ．ｈｕａｓｈａｎｉｃａ丰富，Ｐ．ｈｕａｓｈａｎｉｃａ所有染色体均显较强端带。通过二者带型比较，对华山新麦草是否仍应保留在新麦草属提出质疑，并提出了将新麦草和华山新麦草的基因组分别标为Ｎｊ和Ｎｈ以示区别的建议。

鹌鹑的核型及G带分析

分别采用外周血淋巴细胞培养法和胰酶处理法 ,对鹌鹑染色体的核型和G带进行了研究。结果表明 ,鹌鹑染色体数目为 2n =78,有 10对大染色体 (包括Z、W ) ,2 9对小染色体。染色体形态分别为 :NO .1染色体为sm型 ,NO .2、Z染色体为m型 ,其余染色体均为t型 ,这与前人研究结果存在一定差异。G带分析结果显示 ,鹌鹑的前 9对大染色体及Z、W染色体G带可分为 2 7个区 。

棕色田鼠的细胞遗传学研究

本文首次报道棕色田鼠(Microtus mandarinus)的核型,核型公式为2n=50=2(M,T)+2SM+44T+♀XX(M,SM);♂XY(SM,ST)。发现第一对常染色体及X性染色体存在多态现象。在所研究的15只雌性个体中有7只雌性个体的细胞中只有1条X性染色体,性染色体组成为XO型,核型公式为2n=49=2(M,ST)+2SM+44T+XO。其中X性染色体不同于雄体中的X(SM),为M类型。本文提出的棕色田鼠3种核型与Brown等人(1964)提出的Microtus oregoni的3种核型(XO、YO、XY)有异。本文还阐述了染色体多态产生的机制和探讨了XO型个体发生的机理及其繁殖。

小熊猫染色体异染色质的显示

以培养的小熊猫外周血淋巴细胞为实验材料，结合C-显带技术及CMA／DA／DAPI三重荧光染色的方法，对小熊猫的染色体组型、C-带带型以及CMA／DA／DAPI荧光带带型进行了研究。发现：①经C-显带技术处理，可在小熊猫染色体上呈现出一种极为独特的C-带带型．在多数染色体上可见到丰富的插入C-带（intercalaryC－bands）及端粒C-带，而着丝区仅显示弱阳性C-带；②除着丝粒区外，CMA诱导的大多数强荧光带纹与C-阳性带纹的出现位置具一致性，表明小熊猫染色体的这些阳性C-带富含GC碱基；③14号染色体为短臂中部具次级缢痕的中着丝粒染色体，是小熊猫的标记染色体，其着丝粒区显示强阳性C-带。