直拉硅单晶原生微缺陷的观察

对沿<100>方向生长的p型和沿<111>方向生长的n型宏观无位错直拉硅单晶,用铜缀饰X射线形貌术和腐蚀法观察到两种不同类型的微缺陷,对n型硅单晶还观察到一种特殊组态的微缺陷。对观察到的微缺陷的分布、组态进行了初步的分析。本文首次采用X射线透射投影和截面形貌术对硅单晶原生微缺陷进行直接观察,获得了相应的微缺陷图。所观察到的微缺陷的组态、尺度、分布等与铜缀饰X射线透射形貌图所示结果一致。 关键词：     

缺陷铁纳米环体系的磁特性研究

采用Monte Carlo方法与快速傅里叶变换微磁学方法相结合的方式,模拟含不同缺陷的铁纳米环的磁滞回线、组态、剩磁等磁特性.研究发现:缺陷的大小与位置明显影响系统的磁化过程.当缺陷较小时,系统存在双稳态特征,此性质与无缺陷系统类似;当缺陷增大时,系统过渡状态增加,双稳态特征不再明显.进一步的研究发现,缺陷系统的剩磁随缺陷半径D的增大而增大.上述结果与非对称纳米环系统的磁特性类似,并可以通过零场状态下的系统自旋组态的变化加以解释.当系统圆心与缺陷中心的间距Y增加时,剩磁与Y的关系是非线性的:剩磁先随Y的增大而增大,后随Y的增大而减小.模拟结果可用零场状态下不同Y值的组态变化进行详细解释.上述研究结果表明,缺陷可以明显影响铁纳米环的磁特性.     

有铁心超导电机阻尼屏蔽系统性能分析

有铁心超导电机边界条件复杂、磁场计算易受铁心饱和影响,且电机等效参数与频率、阻尼屏蔽系统(DSS)的材料和结构有关,导致已有解析法在分析此类电机DSS性能方面受到限制.本文将励磁绕组等效为探测线圈,基于时谐场有限元法分析了交变磁场在励磁绕组中的感应电流的变化情况,并基于此计算了DSS的屏蔽系数;将时域法引入到超导电机直轴和交轴超瞬态参数的计算,分析了超导电机接入无穷大电网时电机的阻尼特性.以一台500kW有铁心超导电机为例,分析了影响DSS性能的因素,计算结果表明,电导率高、厚度大的DSS对交变磁场的屏蔽性能更好,但其阻尼性能却较差.因此,为了获得DSS的最佳的性能,对其屏蔽系数和阻尼性能的准确计算和综合考量是十分重要的.     

含奇异材料的掺杂一维光子晶体色散关系和空间局域度理论

给出了描述掺杂的一维光子晶体结构缺陷态的变化规律及其空间局域度特性的理论表达式.该式对由具有任意色散关系材料组成的、中间掺杂、两边对称的一维光子晶体结构均成立.通过研究含奇异材料的光子晶体组态发现，当缺陷层材料为右手材料时，光子带隙中缺陷态的频移方向随缺陷层厚度的增大而红移；当缺陷层材料是左手材料时，频移方向刚好相反，表现为蓝移.该缺陷态的空间局域度只与两边对称结构有关.两边对称结构含奇异材料的光子晶体的缺陷态比传统右手材料的结构具有更强的空间局域度.     

缺陷位置对单层石墨烯拉伸形变的影响

采用AIREBO势函数,对含有多种空位缺陷的单层石墨烯进行分子动力学拉伸模拟,计算不同空位缺陷的位置和排布结构对单层石墨烯应力-应变的影响.结果表明：石墨烯拉伸过程中空位缺陷对其力学性能影响较大.石墨烯内缺陷位置、缺陷排布对拉伸过程中发生的撕裂现象有不同程度的影响.对比分析发现,远离石墨烯边界的空位缺陷对其力学稳定性影响较大.通过控制石墨烯中缺陷的位置,可实现对其力学性能的调控.     

含分层损伤复合材料层合板的动力破坏分析

复合材料层合板在制造和使用过程中可能会产生缺陷，大规模的缺陷将弱化结构的力学性能，在外载作用下，某些损伤扩展又将导致结构的早期失效。为了保证结构在服役期间内的安全和可靠性，要求结构在外载作用下，其初始缺陷和损伤的增长或扩展控制在一定范围内，以使其满足剩余强度的要求。     

局部强组态相互作用及其对ClⅨ—CaⅫ离子2P~44f组态能级结构的影响

利用包括相对论效应的组态相互作用理论方法，详细研究了类氟等电子系列ＣｌⅨ－ＣａⅫ离子的奇宇称激发态结构，讨论了存在于这些离子上的局部强组态相互作用及其对２Ｐ４４ｆ组态能级结构的影响，具体给出了包括强组态相互作用效应修正的能级的计算结果。     

a-Si:H薄膜中Si_yH_x结构组态的原子模拟研究

氢化非晶硅薄膜(a-Si:H)中Si_yH_x结构组态对薄膜应用性能有重要影响,然而现有的分析测试手段难以对其进行深入细致的研究.本文运用分子动力学方法模拟分析了a-Si:H/c-Si薄膜中Si_yH_x结构组态,以及衬底温度对其含量的影响;并进一步运用第一性原理方法计算了各Si_yH_x组态中的Si-H键能.结果发现aSi:H薄膜中Si_yH_x结构可以归纳为六种组态.三类为以化学键结合的SiH_x组态,包括SiH,SiH_2和SiH_3;另外三类为以物理键结合的HSi_y组态,包括HSi_2(s),HSi_2(1)和HSi_3.键能结果反映出六种组态的稳定性由高到低的顺序为SiH SiH_2 SiH_3 HSi_2(s) HSi_2(1) HSi_3.HSi_y组态中Si-H键能在太阳光中的可见光和红外线的能量范围内,阳光照射引起HSi_y组态中的Si-H物理键断裂,是非晶硅薄膜电池产生S-W (SteablerWronski)效应的主要机理.另外,薄膜沉积过程中衬底温度的升高将导致各类SiyH_x组态含量大幅降低.     

局部强组态相互作用及其对ClⅨ—CaⅫ离子2p^44f组态能级…

利用包括相对论效应的组态相互作用理论方法，详细研究了类氟等电子系列ＣｌⅨ－ＣａⅫ离子的奇宇称激发态结构，讨论了在存在于这些离子上的局部强组态相互作用及其对２ｐ＾４４ｆ组态能级结构的影响，具体给出了包括强组态相互作用效应修正的能级的计算结果。     

线缺陷对硅烯力学性能的影响

硅烯是一种类似石墨烯的二维硅,由于其与石墨烯类似的电子特性以及与现有半导体技术的兼容性而引起了人们的广泛关注。采用基于分子动力学理论的Forcite模拟软件包对含不同条数、不同位置的线缺陷硅烯薄膜的超晶胞体系进行优化,并计算和分析了其力学性能。结果表明：随着线缺陷位置的变化,硅烯薄膜的拉梅常数、泊松比、体积模量、杨氏模量和剪切模量变化趋势基本吻合,说明硅烯的力学性能受线缺陷位置影响不敏感;伴随着线缺陷条数的增加,五环和八环密度升高,硅烯薄膜力学性能拉梅常数、泊松比、体积模量和剪切模量变化幅度小,影响不大,而扶手椅方向的杨氏模量线性增加,锯齿型方向的杨氏模量线性减小。     

Influence of a high-speed dielectric spherical particle''s movement on its scattering characteristics

The scattered field and differential scattered section (DSS) of a moving spherical particle with a high speed are investigated numerically. The coordinate and vector transformations are used to establish a theoretical basis for studying the laser scattering of a moving particle. The DSS of a moving spherical particle is explained by the electric and magnetic field from Mie scattering theory. Assuming the laser wavelength of 1.06 μm, we compute the ratio of the laser DSS of the moving dielectric spherical particle to that of the static dielectric spherical particle, which changes with radii, speeds and scattering angles of the particle. The numerical results show that the laser DSS of the oving pherical particle is tightly connected with its speed and scattering zenith angle. If a spherical particle moves with high speed, the laser DSS due to movement of the particle could not be neglected. If the speed of the dielectric spherical particle is fluctuating, the Doppler effect and the frequency spectrum expansion play important roles.     

乙基紫共振瑞利散射光谱法测定葡聚糖硫酸钠

在Britton-Robinson缓冲介质(pH 9.0～10.5)中,单独的乙基紫与葡聚糖硫酸钠的共振瑞利散射都非常微弱,当二者反应形成结合物时将导致溶液共振瑞利散射明显增强,并产生新的共振瑞利散射光谱,其3个明显的散射峰分别位于348.0,509.8和680.0 nm处,且均可作为测定波长。以ΔI值最高且线性关系较好的509.8 nm作为测定波长时,葡聚糖硫酸钠在0.005～2.4 μg·mL-1范围内与共振瑞利散射强度成线性关系,检出限为3.25 ng·mL-1。研究了葡聚糖硫酸钠-乙基紫体系的紫外-可见吸收光谱,讨论了溶液酸度、乙基紫浓度、反应时间、温度、离子强度等实验条件的影响,考察了共存物质对该体系测定葡聚糖硫酸钠的影响。实验表明该方法有高的灵敏度和较好的选择性,应用于合成样品的测定。     

Cellular dislocation substructure in polycrystals of FCC solid solutions: quantitative characteristics,laws of formation,and role in hardening

A cycle of investigations carried out by the authors and devoted to the most important cellular dislocation substructure is generalized. Laws of formation of this substructure upon plastic strain of FCC Cu–Mn and Cu–Al alloy polycrystals are considered. The influence of the grain size, strain temperature, and alloy concentration on the parameters of evolving cellular dislocation substructures (DSS) is quantitatively analyzed by the transmission electron microscopy (TEM) method. Special attention is given to the kinetic phase transition in the defect subsystem leading to the formation of the cellular DSS. Based on modern dislocation models, it is demonstrated that hardening by the cellular DSS obeys the main dislocation laws.     

Ion exchange study of carbonate,nitrate and dioctyl sulfosuccinate with anthraquinone-2-sulphonate encapsulated in inorganic layered structures

Layered organic–inorganic hybrid composite of anthraquinone 2-sulfonate (AQ2) with Zn–Al layered double hydroxide (LDH) was prepared and its ion exchange was examined with carbonate, nitrate and dioctyl sulfosuccinate (DSS) in aqueous environment at various concentrations of the sodium salt solutions, 0.05, 0.1 and 0.2 M, at room temperature. The ion exchange procedure produced an LDH or another material of which basal spacing was shrinked or expanded from 19 to 7.4, 23.4 to 24.4 and 19.1 to 19.5 Å for carbonate, DSS and nitrate ion exchanged, respectively, depending on the concentration. This is due to the size and the orientation of the anions, which is accommodated in the LDH inorganic layered structure. Ion exchange was found to be completed for carbonate and DSS. However, no ion exchange can be observed for nitrate. This indicates that carbonate and DSS have a higher affinity than AQ2 to be intercalated into the inorganic layered structure. On the other hand, nitrate has a lower affinity than AQ2. Therefore, the affinity of the anion shows the trend: CO₃²⁻≳DSS>AQ2>NO₃⁻ under our experimental conditions.     

Complexity of routes to chaos and global regularity of fractal dimensions in bimodal maps

The dual-star composition rule of doubly superstable (DSS) sequences presents a complete renormalizable algebraic structure for studying Feigenbaum's metric universality and self-similar classification of DSS sequences in symbolic dynamics of bimodal maps of the interval. Here an important feature is that the complete combinations of up- and down-star products create all the generalized Feigenbaum's routes of transitions to chaos. These routes can be classified into two types: one consists of countably infinitely many regular routes which preserve Feigenbaum's metric universality; another consists of uncountably infinitely many universal nonscaling routes described by the irregularly mixed dual-star products, which break Feigenbaum's asymptotically convergent metric universality although they are structurally universal. The combinatorial complexity of dual-star products may increase the grammatical complexity of languages of symbolic dynamics. Moreover, it is found that there exists a global regularity between the fractal dimensions d and the scaling factors [alpha(C),alpha(D)] for Feigenbaum-type attractors: d(Z)log(/Z/)/alpha(C)(Z)alpha(D)(Z)/=beta((2)), where beta((2)) is independent of the concrete DSS sequences Z.     

Synthesis and Properties of Layered Organic–inorganic Hybrid Material: Zn-Al Layered Double Hydroxide–dioctyl Sulfosuccinate Nanocomposite

A layered organic–inorganic hybrid nanocomposite was prepared by using a surfactant, dioctyl sulphosuccinate (DSS) as a guest in Zn-Al layered double hydroxide (LDH) inorganic host by a self-assembly technique. The Zn-Al ratio of the mother liquor was kept constant at 4 at the beginning of the synthesis. Powder X-ray diffractogram shows that the basal spacing of the Zn-Al LDH with sulphate as the intergallery anion (ZASUL) expanded from 11.0 to 26.3Å to accommodate the DSS surfactant anion for the formation of the Zn-Al LDH–DSS layered organic–inorganic hybrid nanocomposite (ZADON). It was also found that the BET surface area reduced by about 90%, from 22.5 to 2.2m²/g, for ZASUL and ZADON, respectively if 0.1M DSS was used for the synthesis of the latter.     

Accurate determination of the number density of G-phase precipitates in thermally aged duplex stainless steel

G-phase precipitation in the ferrite phase in thermally aged duplex stainless steel (DSS) was investigated. A needle-shaped sample of DSS aged at 673?K for 5000?h was observed by transmission electron microscopy (TEM), and subsequently by atom probe tomography (APT). The precipitates of the G-phase observed by TEM corresponded well to clustering atoms observed by APT. On the other hand, regarding the precipitates of the G-phase that formed in an earlier stage of aging, the present study suggests that not all the precipitates can be detected by TEM. A large area of DSS aged at 673?K for 5000?h containing both the ferrite and austenite phases was observed. The number density of precipitates of the G-phase in the ferrite phase was small in the vicinity of the phase boundary and increased with the distance between the phase boundary and each field of view. The number density reached an almost constant value at a distance of approximately 4?µm from the phase boundary. The suppression of G-phase precipitation in the vicinity of the phase boundary is discussed in terms of the depletion of alloying elements that comprise the G-phase.     

Discrete state space method and modal extension method based impact sound synthesis model

The efficient and accurate synthesis of physical parameter-controllable impact sounds is essential for sound source identification. In this study, an impact sound synthesis model of a cylinder is proposed based on discrete state space(DSS) method and modal extension method(MEM). This model is comprised of the whole three processes of the physical interaction, i.e., the Hertz contact process, the transient structural response process, and the sound radiation process. Firstly,the modal expanded DSS equations of the contact system are constructed and the transient structural response of the cylinder is obtained. Then the impact sound of the cylinder is acquired using improved discrete Raleigh integral. Finally, the proposed model is verified by comparing with existing models. The results show that the proposed impact sound synthesis model is more accurate and efficient than the existing methods and easy to be extended to the impact sound synthesis of other structures.     

机械能守恒定律和相对性原理

详细阐述了机械能守恒定律成立的条件及该定律服从力学相地性原理所需满足的条件,回答了《河北师范学院学报（自然科学版）》在１９９７年第２期上赵佩章等同志对本刊多年来氯表的有关文章的批评     

机械驻波的电学方法演示

驻波现象的演示，常是采用系在一水平细绳上的音叉的振动，观察波在细绳中的传播，本文介绍利用交流电演示驻波现象的方法，其效果更为明显。