A distance regular graph of typeE 1° E d

In this note, the distance regular graph of typeE _1° E _d is considered and some characterization of the type graph is given. The results generalize the characterization of tight distance regular graphs.     

李型单群~2G_2(q)阶分量刻画的简化证明

不使用单群分类定理,给出了Sylow 2-子群阶数不大于8的有限单群的完全分类.并在此基础上,简化了李型单群~2G_2(q)阶分量刻画的证明.     

Study on delayed cracking of conductive notch under electric field in PZT-5H ferroelectric ceramics

Internal electrodes have widely been adopted in electronic and electromechanical devices made of ferroelectric ceramics. There embedded electrodes naturally function as a pre-conductive notch, which lead to the failure of the devices under electric and/or…     

A class of quasisymmetric mappings with substantial points

It is proved thatK _q (h)=K ₀(h) for everyh in some class of quasisymmetric mappings of the unit circle with substantial points, whereK _q (h):=sup{M(h(Q))/M(Q);Q is a quadrilateral with the domain unit disk} andK ₀(h) is the extremal maximum dilatation ofh.     

Effect of the free surface on the earthquake energy: A case study of reverse faulting

Based on the representation theorem of seismic energy radiation, in this study, we have quantitatively investigated the effect of free surface on the radiation energy distribution due to a coupling interaction between free surface and near surface finite fault for the reverse earthquake faulting. Corresponding to the finite faulting, a 2-D pseudostatic-reverse-fault-dislocation solution has been used in the calculation of the work done by the seismic response against free surface. The results indicate that, due to a strong coupling interaction between the free surface and near surface fault, the total radiated seismic energy ER is much larger than that radiated only from the fault itself （EF）, especially for the shallow reverse faulting. In convention, EF is commonly used in the estimation of earthquake energy radiation. However, when the fault depth H, the distance between the free surface and top of fault location, increases, the effect of the coupling interaction between the fault and free surface decreases gradually. Therefore, the total radiated energy ER approaches to the EF when the depth H is about 2 times the fault length L The current study could provide us a partial explanation of the apparent stress discrepancy observed at the far field and near field in the recent large earthquake. Moreover, the current study also has a significant implication of how to quantitatively describe the near fault strong ground motion and associated seismic hazard from the earthquake source energy point of view.     

The nonwandering set of some Hénon map

For the Hénon mapT _{a, b}(x, y) = (1 −ax ² +y, bx), Benedicks and Carleson proved that for (a,b) near (2, 0) andb > 0, there exists a setE with positive Lebesgue measure, whose corresponding mapT _{a, b} possesses a strange attractor. Viana conjectured that if (a, b) ∈E, then the nonwandering set of the mapT _a, b Ω(T_{a, b}) = ∧_{a, b},Uq _a, b, where ∧_{a, b}, is the strange attractor, q_a,b is a hyperbolic fixed point in the third quadrant. It is proved that this conjecture holds true for a positive measure set E₁ ⊂E.     

The preparation and characterization of amorphous SiCN thin films

Radio Frequency plasma enhanced Chemical Vapor Deposition (RF CVD) using N₂, SiH₄ and C₂H₄ as the reaction sources was used to prepare amorphous ternary Si _x C _y N _z thin films. The chemical states of the C, Si and N atoms in the films were characterized by X-ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FTIR). The refractive indexn, extinction coefficientk and optical band gapE _opt of the thin films were investigated by UV-visible spectrophotometer and spectroscopic ellipsometer. The results show that a complex chemical bonding network rather than a simple mixture of Si₃N₄, SiC, CN _x and a-C etc., may exist in the ternary thin films. Then's of the films are within the range of 1. 90–2. 45, andE _opt's of all samples are within the range of 2. 71–2. 86 eV. Foundation item: Supported by the National Natural Science Foundation of China (19975035) Biography: Li Jin-chai (1946-), male, Professor, research direction: novel functional materials films & ion beam modification of materials.     

Simulation of maximum light use efficiency for some typical vegetation types in China

MAXIMUM LIGHT USE EFFICIENCY(ΕMAX)IS THE USE RATE OF PHOTOSYNTHETICALLY ACTIVE RADIATION BY VEGETATION IN AN IDEAL CONDITION WITHOUT ANY CONSTRAINTS.IT IS A PHYSIOLOGICAL ATTRIBUTE OF PLANT ITSELF.THE VALUE OFΕMAX IS DIFFERENT FOR DIFFERENT VEGETATION TYPES[1―5].IT IS A KEY PARAMETER FOR THE ESTIMATION OF NET PRIMARY PRODUCTIVITY(NPP)DRIVEN WITH REMOTE SENSING DATA.THERE…     

Electrical anisotropy of orientedtrans-polyacetylene undoped and doped with SO3

We use extended Huckel methods of molecular orbitds and crystal orbitals (EHMO/CO) to calculate the two-dimensional band structures of highly oriented trans-polyacetylene (PA) undoped and doped with SO3. According to the energy band theory of solids, we explain the changes of band gap (Eg) and bandwidth (BW) from undoped PA to SO3-doped PA, and discuss the electrical anisotropy of oriented trans-polyacetylene doped with SO3. The calculated results show that the conductivity anisotropy ratio (σ///σ⊥) is determined by Eg and BW in the directions both parallel (σ//) and perpendicular (σ⊥) to the PA chains, respectively. The conductivity anisotropy ratio σ///σ⊥ decreases when PA is doped with SO3, because the dopant plays a conjugated bridge role between the interchains of PA, and makes the dopant itself and PA chains show a strong interchain coupling. The theoretical results for undoped and doped PA are in good agreement with experimental ones.     

The distribution characteristics of the flows in the near-Earth region： TC-1 observational results

TC-1 observational results clearly indicate that the velocity of the flows in the near-Earth region is dependent on the satellite location. The flow speed decreases while satellite moves close to the Earth. The plasma flow in the region close to the Earth tends to drift into the midnight region from the dawn and dusk region while the flow in the region away from the Earth shows an opposite drift. The observational results also show that the tailward flows are mainly located in the plasma sheet boundary while the earthward flow becomes dominant in the plasma sheet. It is found that both the strong tailward and earthward flows are distributed in the region around X= -11 Re, which coincides with the trigger region of the substorm onset. Hence, it may suggest that the flows are related with the trigger of the substorm onset. In addition, the BBFs coming from the mid-tail maily distributed in the region where X〈-9R E a n d ｜Z｜ 〈 3 R E that differs from the convection.     

Analysis of active sites for N2 and H^＋ reduction on FeMo-cofactor of nitrogenase

Dinitrogen (N2) and proton (H ),which act as physiological substrates of nitrogenase,are reduced on FeMo-co of the MoFe protein. However,researchers have different opinions about their exact reduction sites. Nitrogenases were purified from the wild type (WT) and five mutants of Azotobacter vinelandii (Av),including Qα191K,Hα195Q,nifV-,Qα191K/nifV- and Hα195Q/nifV-; and the activities of these en-zymes for N2 and H reduction were analyzed. Our results suggest that the Fe2 and Fe6,atoms closed to the central sulfur atom (S2B) within FeMo-co,are sites for N2 binding and reduction and the Mo atom of FeMo-co is the site for H reduction. Combining these data with further bioinformatical analysis,we propose that two parallel electron channels may exist between the 8Fe7S cluster and FeMo-co.     

应用正交试验法的RHT模型参数敏感性研究

基于RHT模型的理论分析,选出A、N、B、M、B_Q、f_s/f_c、T_ten、D₁和E_f,min 9个参数作为正交试验分析参数,研究RHT模型中参数的敏感性.运用Autodyn程序对弹丸侵彻混凝土过程进行数值分析,确定了不同参数、不同水平值下弹丸的侵彻深度.采用极差分析法对参数的敏感程度进行量化分析,得出9个参数的敏感性排序为B > E_f,min > T_ten > f_s/f_c > N > M > D₁ > B_Q > A.结合3组典型数值试验损伤云图和侵彻深度的对比分析,认为参数B、E_f,min和T_ten对数值模拟试验结果的影响极大,应采取可靠的技术手段准确确定其取值.      

单负材料填充包层的矩形波导模式特性

【目的】通过求解矩形波导模式特征方程,计算矩形波导横向场分布,研究电磁波在单负材料矩形波导中的传播特性以及该波导参数对其导模Exmn的影响规律。【方法】基于电磁场的波动理论和马卡梯里假设,利用图解法对波导有效折射率及横向电场分布进行求解,并分析波导模式的频率色散关系。【结果】该矩形波导的传播模式Ex0n和Ex1n为x方向衰减的表面模,仅当m1时,波导的传播模式才是振荡导模;固定波导芯子层厚度不变,当导波频率增大时,高阶模向高频方向移动的速度比低阶的快;保持m1,当m或n增大时,Exmn模式的截止点均向波导孔径增大的方向移动,且相邻模式的截止间距相等。【结论】单负材料包层的矩形波导既支持存在低阶表面模的条件,也支持存在高阶振荡导模的条件,波导孔径大小对导波模有很好的调制效果,可实现宽孔径多模传输和小孔径单模传输的功能。     

On random Taylor series

This paper deals with random Taylor series whose coefficients consist of independent random variables {X _n } with the property: αE ^1/2{|X _n |²}≤E{|X _n |}<∞,E{X _n }=0 (Ån) for some positive constant α. The convergence, growth, and value distribution of the series are investigated. Supported by the National Natural Science Foundation of China (No. 101960433) Ding Xiaoqing: born in Oct. 1958, Doctoral candidate     

Gene flow from transgenic oilseed rape (Brassica napus L.) to cruciferous weeds under mentor pollen inducement

The alien gene flow between genetically modified glyphosate-resistant rapeseed variety Q3 (Brassica napus L.) and four cruciferous weeds was studied under mentor pollen inducement. The results showed that when Thlaspi arvense L., Capsella bursa-pastoris (L.) Medic, Cardamine hirsute L. and Rorippa palustris (L.) Besser were pollinated with mentor pollen, the mixed Q3 and the weed, pollen grains aggregated largely and germinated quickly, and the numbers of pollen tubes penetrating into the style and the ovary were greatly increased as compared with corresponding self-pollination groups. Twenty four to forty eight hours after pollination, several pollen tubes were observed to penetrate into the ovule via micropyle in each mentor combination. However, when the mentor progenies were analyzed by PCR, all of them showed negative for the Q3 herbicide-resistant gene. Collectively, these results indicated that crossing between T. arvense, C. bursa-pastoris, C. hirsuta, R. palustris (as female) and Q3 (as male) was highly incompatible and the herbicide-resistant gene could not flow from Q3 to these four weeds.     

Reconstructing sea surface temperature,sea surface salinity and partial pressure of carbon dioxide in atmosphere in the Okinawa Trough during the Holocene and their paleoclimatic implications

The sediment core DGKS9603 collected from the Okinawa Trough was used as research target. By use of unsaturated indexU ^k₃₇ of long-chain alkenone, δ¹³C of POC and of planktonic foraminifera (G. sacculifer), the evolutions of sea surface temperature and partial pressure of carbon dioxide in the atmosphere during the Holocene were reconstructed in the Okinawa Trough. And in combination of δ¹⁸O of planktonic foraminifera, the relative difference of sea surface salinity during the Holocene was also reconstructed. Consequently, three cooling events (E₁-E₃) were identified, each of which occurred at 1.7-1.6, 5.1-4.8 and 8.1-7.4 kaBP (cal), respectively. Of the three events, E₂ and E₃ are globally comparable, their occurrence mechanism would be that the main stream of the Kuroshio Current shifted eastward due to the enhanced circulation of the northeastern Pacific Ocean, which was driven in turn by amplified intensity of sunshine and subsequent enhancement of subtropical high pressure; E₁ corresponds to the Small Ice-Age Event occurring between 1550 and 1850AD in China. In the Oki-nawa Trough, E₁ might be also related to the eastward shift of main stream of the Kuroshio current driven by powerful Asia winter monsoon.

     

Relationship between stomatal density and the changes of atmospheric CO2 concentrations

The relationship between the stomatal density of five woody plants endemic to China, i. e.Eucommia ulmoides, Quercus liaotungensis, Q. glandulifera var.brevipetiolata, Cyclocarya paliurus andFicus heteromorpha, and the atmospheric CO₂ concentrations was studied by observations on leaves of the herbarium-stored specimms(1920s–1990s). The results showed that the stomatal density inEucommia ulmoides, Quercus liaotungensis andQ. glandulifera var.brevipetiolata decreased significantly in response to the elevated atmospheric CO₂ concentrations, while inCyclocarya paliurus it decreased slightly and inFicus heteromorpha there were no responses.     

A complete set of addition laws for twisted jacobi intersection curves

A complete system of addition laws on an elliptic curve E is a collection of addition laws with the property that for any pair of points P1,P2 on E at least one of the addition laws in the collection can be used to compute P1+P2.This paper proposes a complete set of the addition laws for arbitrary twisted Jacobi intersection curve.     

Gene flow from transgenic oilseed rape (Brassica napus L.) to cruciferous weeds under mentor pollen inducement

The alien gene flow between genetically modified glyphosate-resistant rapeseed variety Q3 (Brassica napus L.) and four cruciferous weeds was studied under mentor pollen inducement. The results showed that when Thlaspi arvense L., Capsella bursa-pastoris (L.) Medic, Cardamine hirsute L. and Rorippa palustris (L.) Besser were pollinated with mentor pollen, the mixed Q3 and the weed, pollen grains aggregated largely and germinated quickly, and the numbers of pollen tubes penetrating into the style and the ovary were greatly increased as compared with corresponding self-pollination groups. Twenty four to forty eight hours after pollination, several pollen tubes were observed to penetrate into the ovule via micropyle in each mentor combination. However, when the mentor progenies were analyzed by PCR, all of them showed negative for the Q3 herbicide-resistant gene. Collectively, these results indicated that crossing between T. arvense, C. bursa-pastoris, C. hirsuta, R. palustris (as female) and Q3 (as male) was highly incompatible and the herbicide-resistant gene could not flow from Q3 to these four weeds.     

TaAgN复合膜显微结构、力学性能和摩擦性能的研究

采用非平衡反应磁控溅射法制备了TaAgN复合膜。利用X射线衍射仪、CSM纳米压痕测试仪和摩擦磨损测试了复合膜的显微结构、力学性能和摩擦性能。结果显示,TaAgN复合膜由面心立方结构的TaN相和底心斜方结构的Ta₄N相组成。随着Ag靶功率的增加,硬度H、弹性模量E、弹性恢复W_e和H³/E²值均呈先升高后降低的趋势,最大值分别为34 GPa,394 GPa,57%和250 MPa。随着Ag靶功率的增加,TaAgN复合膜室温下的平均摩擦因数呈降低趋势。当Ag靶功率为25 W时,随着温度的升高,TaAgN复合膜的平均摩擦因数逐渐减小。