基于基因规划的主机异常入侵检测模型

异常检测技术假设所有的入侵行为都会偏离正常行为模式.尝试寻找一种新的异常入侵检测模型改善准确性和效率.模型利用应用程序的系统调用序列,通过基因规划建立了正常行为模式.模型的一个例程管理一个进程.当它发现进程的实际系统调用序列模式偏离正常的行为模式时,会将进程设标记为入侵,并采取应急措施.还给出了基因规划的适应度计算方法以及两个生成下一代的基本算子.通过与现有一些模型的比较,该模型具有更好的准确性和更高的效率.

A Compact Direct Digital Frequency Synthesizer for the Rubidium Atomic Frequency Standard

A compact direct digital frequency synthesizer （DDFS） for system-on-chip implementation of the high precision rubidium atomic frequency standard is developed. For small chip size and low power consumption, the phase to sine mapping data is compressed using sine symmetry technique, sine-phase difference technique, quad line approximation technique,and quantization and error read only memory （QE-ROM） technique. The ROM size is reduced by 98% using these techniques. A compact DDFS chip with 32bit phase storage depth and a 10bit on-chip digital to analog converter has been successfully implemented using a standard 0.35μm CMOS process. The core area of the DDFS is 1.6mm^2. It consumes 167mW at 3.3V,and its spurious free dynamic range is 61dB.

A High Performance AlGaN/GaN HEMT with a New Method for T-Gate Layout Design

We propose and fabricate an A1GaN/GaN high electron mobility transistor （HEMT） on sapphire substrate using a new kind of electron beam （EB） lithography layout for the T-gate. Using this new layout,we can change the aspect ratio （ratio of top gate dimension to gate length） and modify the shape of the T-gate freely. Therefore, we obtain a 0.18μm gate-length AlGaN/GaN HEMT with a unity current gain cutoff frequency （f_T） of 65GHz. The aspect ratio of the T-gate is 10. These single finger devices also exhibit a peak extrinsic transconductance of 287mS/mm and a maximum drain current as high as 980mA/mm.

棘蛙族(Tribe Paini)精子形态结构及精巢年周期研究

棘蛙族(Tribe Paini)隶两栖纲(Amphibia)、无尾目(Anura)、蛙科(Ranidae)、叉舌蛙亚科(Dicroglossinae)，由棘蛙属(Paa)、倭蛙属(Nanorana) 和沙巴蛙属(Chaparana)构成（Dubois,1992）。由于特殊的形态特征和染色体核型，棘蛙族受到国内外学者的广泛重视和研究，但是到目前为止，棘蛙族的系统发育关系尚未明晰，族下属种的分类和归属问题还有待进一步研究和新的证据出现。本文通过光学显微镜、电子显微镜和石蜡切片对棘蛙族10 物种的精子和精巢进行研究，旨在了解棘蛙族精子的形态、量度、超微结构特征及不同季节精巢结构的变化规律，同时为棘蛙族的系统研究提供新的依据，也为棘蛙族濒危物种的保护和经济物种的繁殖提供基础资料。研究结果表明：棘蛙族各属物种精子的形态基本相似，精子整体呈线形，由头部、中片和尾部构成。精子头部呈长条状，顶体呈锥状，位于头部顶端并向前伸出，中片较长，尾部波动弯曲。棘蛙族各属物种精子量度差异较大，将各属物种精子头部、中片、尾部、头宽、尾宽的量度数据进行聚类分析，结果表明棘蛙族10 物种可分为三类：第一类包括棘侧蛙、合江棘蛙、小棘蛙、棘腹蛙和棘胸蛙，特点是精子较短，全长在72.6～103.35µm 之间；第二类包括倭蛙、高山倭蛙、腹斑倭蛙，特点是精子较长，全长在107.74～129.75µm 之间；第三类包括隆肛蛙和双团棘胸蛙，特点是精子最长，全长在145.89～165.84µm 之间。棘蛙族各属精子超微结构基本相似：精子头部由顶体、细胞核构成；中片由中心粒、线粒体构成；尾部由单根轴丝构成。精子顶体横切呈圆环状，细胞核电子密度高；线粒体为卵圆形，呈环状围绕轴丝排列，线粒体数目较多，约30层；尾部轴丝为典型的9＋2结构，即由2根中央微管和9对外周微管组成。不同季节的倭蛙精巢结构变化表明倭蛙精巢每年只有一个生精周期，生精周期始于7 月，繁殖季节从5 月到6 月，生精高峰期为9 月；根据倭蛙不同季节精巢结构的变化，可将生精周期分为3 个阶段：第一阶段从7 月到9 月，为精子形成期；第二阶段从10 月到翌年4 月，为精子的贮存阶段，也即倭蛙的冬眠期；第三阶段从5 月到6 月，为精子的排放阶段，即倭蛙的繁殖期。不同季节的隆肛蛙精巢结构变化表明5 月为隆肛蛙的繁殖高峰期。根据棘蛙族各属精子的形态、量度和超微结构特征，结合已有的棘蛙族形态学、生态学、染色体核型及系统学研究成果，本文认为：1．基于精子数据对棘蛙族的划分和基于形态学及分子系统学数据对棘蛙族的划分均有相同之处，精子形态结构可为棘蛙族的系统研究提供新的证据。2． 棘蛙族各属精子的形态、量度及超微结构不仅与蛙科其他属种有明显差异，而且在无尾类中也较为特殊，精子学研究结果支持将棘蛙族从蛙科中分离出来，归隶于叉舌蛙科的叉舌蛙亚科的系统学修正。3. 精子的顶体、细胞核、中片的形态结构及量度可作为蛙科的分类指标。On the base of unique morphological and kyrotype characters, Dubois(1992)recognized three genera Paa, Narnorana, Chaparana as tribe Paini, which is amember of Dicroglossinae, Ranidae. In present study, the sperm shape, size andultrastructure of 10 paini species were investigated through the light and electronmicroscope, and testis structure of N. pleskei and F. quadrana was also studied. Wesuppose this study could offer some spermatological evidence to phylogeny andreproduction study of tribe Paini. The results were as follows:The sperm shape of tribe paini is homologically similar, the spermatozoa arefiliform, composed of elongate head, long mid-piece and waved tail. The acrosome isapically associated with the nucleus and extend anteriorly.The sperm length of tribe paini differ remarkably among genera. Cluster for thelength of sperm head, mid-piece, tail, total length, head-width, tail-width of ten painifrogs indicated the 10 species could be separated into three groups: GroupⅠcontainsP. shini, P. robertingeri, P. spinosa, P. exilispinosa, P. boulengeri, the spermatozoa ischaracterized with short in total length, ranging from 72.6µm to 103.35µm; GroupⅡcontains N. pleskei, N. parkeri, N. ventripunctata, the spermatozoa ischaracterized with relatively long in total length, ranging from 107.74µm to129.75µm; Group Ⅲ contains F. quadrana and P. yunnanensis, the spermatozoa is characterized with longest in total length, ranging from 145.89µm to 165.84µm. thethree groups based on spermatological data is partially match the classification basedon morphological and molecular data.The ultrastructure of spermatozoa in tribe paini is also basic similar, includingacrosome vescile, nuleus of the head proper, centriole, mitochondriol of themid-pieces, axoneme of the tail. The acrosome vescle is circle in TEM transversesection, the density of nucleus is high; The mitochondrions is oval, surrounding theaxial filament with about 30 layers of mitochondria; The axoneme has the typical 9+2pattern of microtubules.The seasonal changes in testis of N. pleskei indicates it has only onespermatogenesis circle, which begin in July, the reproduction season is from May toJune, the spermatogenesis is active in September. On the base of seasonal changes intestis, the spermatogenesis circle can be separated into three stages: In stageⅠfromJuly to September, spermatids are formed; In stage Ⅱ from October to April next year,the spermatozoa are stored in testis,which is the hibernated period; In stage Ⅲ fromMay to June, mature spermatozoa were released from the testis, which is thereproduction season of N. pleskei. As to F. quadrana, reproduction is active in May.With the previous study of morphology, ecology, karyotypes and phylogenyresearch of tribe Paini, the spermatological data in present study suggests:1. The spermatological classification of tribe paini is partially consistant with themorphological and molecular classification respectively.2.The sperm morphology and ultrustructure of tribe paini is unique not only inthe family Ranida but also in Anura, which suggest the tribe paini is monophyletic andmight be transfered from the family Ranida to the family Dicroglossidae based onmolecular evidence.3. The acrosome, nuleus, shape, length and ultrastructure of mid-piece can beused as an alternative taxonomic character in Anura.

相对论连续无规位相近似研究核的巨单极共振

<正>在相对论连续无规位相近似(RCRPA)框架下,研究了有限核同位旋标量巨单极共振(ISGMR)。在这个方法中,用单粒子格林函数方法严格处理连续态对粒子-空穴激发的贡献。在无海近似下,

L-shell ionization accompanied by one-electron capture in Cq+, Oq+ (q=2,3)-Ne collisions

The L-shell ionization processes of a Ne gas target associated with single-electron capture by bombardment of Cq+ and Oq+ (q=2,3) are investigated using the projectile-recoil-ion coincidence method in the energy range from 80 to 400 keV/u (v(p)=1.8-4 a.u.). The cross-section ratios (R-k1) of k-fold ionization to single capture are compared with the results for He2+-Ne collisions by Dubois [Phys. Rev. A 36, 2585 (1987)]. All the velocity dependences are quite similar. The ratios increase as the projectile energy increases in the lower-energy region, reach the maxima for projectile energies around E-max=160q(1/2) keV/u, and then decrease at higher energies. These results qualitatively agree with our calculations in terms of the Bohr-Lindhard model within the independent-electron approximation.

Anomaly in the charge radii and nuclear structure

The axially deformed relativistic mean field theory is applied to study the isotope shift of charge distributions of odd-Z Pr isotope chain. The nuclear structure associated with the shell and the isotope effect is investigated. The mechanism of link in the isotope shift at the neutron magic number N = 82 is revealed to be dependent on the neutron energy level structure at the Fermi energy, demonstrating that the spin-orbit coupling interaction and p-n attraction are well described by the relativistic mean field theory.