Moisture Structure of the Quasi-biweekly Mode Revealed by AIRS in Western Pacific

Using Atmospheric Infrared Sounder （AIRS） humidity profiles, rainfall from the Tropical Rainfall Measuring Mission （TRMM） Global Precipitation Index （GPI）, Quick Seatterometer （QSCAT） satellite-observed surface winds, and SST from the Advanced Microwave Scanning Radiometer for NASA＇s Earth Observing System （AMSR_E）, we analyzed the structure of the summer quasi-biweekly mode （QBM） over the western Pacific in 2003-2004. We find that the signal of 10 20-day oscillations in the western Pacific originates from the Philippine Sea, and propagates northwestward toward South China. The AIRS data reveal that the boundary-layer moisture provides preconditioning for QBM propagation, and leads the mid-troposphere moisture during the entire QBM cycle. The positive SST anomaly leads or is in-phase with the boundary- layer moistening, and may be a major contributor. Most likely, the 10 20-day SST anomaly positively feeds back to the atmosphere by moistening the boundary layer, destabilizing the troposphere, and leading the QBM to propagate northwestward in the western North Pacific. However, the ECMWF/TOGA （Tropical Ocean and Global Atmosphere） analysis does not display boundary-layer （BL） moisture anomalies leading the mid-troposphere moisture.

Vertical structure of variabilities in the tropical easterly jet and associated factors

热带东风急流为热带上对流层-下平流层内夏季出现的一支强东风带,其垂直范围为300-70hPa,目前其垂直结构的变化特征有待研究.本文利用经验正交函数分解研究了热带东风急流纬向垂直剖面的主要模态。第一模态表现为垂直方向上急流强度的一致变化.ENSO对第一模态的年际分量具有主导贡献,而大西洋年代际振荡和太平洋年代际振荡可能调制其年代际分量第二模态表现为热带东风急流垂直位移的年际变化.热带平流层准两年振荡不同位相的相继下传既可以直接影响对流层顶的纬向风异常,也可以通过改变海洋性大陆附近的对流异常影响热带东风急流的垂直位置.

Broadband Response of Second Harmonic Generation in a Two-Dimensional Quasi-Random Quasi-Phase-Matching Structure

The broadband response of second harmonic generation(SHG)is experimentally observed in a two-dimensional(2D)quasi-random quasi-phase-matching(QPM)structure.A nonlinear conversion efficiency of more than 50%is obtained.Due to the line-type distribution of the reciprocal vector,the second harmonic wave(SHW)covering a broad frequency band is efficiently radiated in the shape of one single spot or three spots instead of a stripe.This is believed to be favorable for its practical application and paves the way for the use of ultrahigh-bandwidth light sources and devices in modern optical technologies.

On Quasi-Jacobi Bialgebroid and Its Dirac-Jacobi Structure

Notions of quasi-Jacobi bialgebroid and its Dirac-Jacobi structure are introduced.The necessary and sufficient conditions for a maximal isotropic subbundle L to be a DiracJacobi structure are proved.Meanwhile several special examples are presented.

Quasi-distribution Appraisal about Finite Element Analysis of Multi-functional Structure Made of Honeycomb Sandwich Materials

A new appraisal method（QDA, quasi-distribution appraisal） which could be used to evaluate the finite element analysis of multi-functional structure made of honeycomb sandwich materials is developed based on sub-section Bezier curve. It is established by simulating the distribution histogram data obtained from the numerical finite element analysis values of a satellite component with sub-section Bezier curve. Being dealt with area normalization method, the simulation curve could be regarded as a kind of probability density function（PDF）, its mathematical expectation and the variance could be used to evaluate the result of finite element analysis. Numerical experiments have indicated that the QDA method demonstrates the intrinsic characteristics of the finite element analysis of multi-functional structure made of honeycomb sandwich materials, as an appraisal method, it is effective and feasible.

Heuristic Quasi-physical Algorithm for Protein Structure Prediction

A three-dimensional off-lattice protein model with two species of monomers, hydrophobic and hydrophilic, is studied. Enligh- tened by the law of reciprocity among things in the physical world, a heuristic quasi-physical algorithm for protein structure prediction problem is put forward. First, by elaborately simulating the movement of the smooth elastic balls in the physical world, the algorithm finds low energy configurations for a given monomer chain. An ＂off-trap＂ strategy is then proposed to get out of local minima. Experimental results show promising performance. For all chains with lengths 13≤n ≤55, the proposed algorithm finds states with lower energy than the putative ground states reported in literatures. Furthermore, for chain lengths n = 21, 34, and 55, the algorithm finds new low energy configurations different from those given in literatures.

Mild Hydrothermal Synthesis,Crystal Structure and Magnetic Behavior of AgCu(IO_3)_3:a Quasi-one-dimensional S=1/2 Chain Compound

A new complex AgCu（IO3）3 is synthesized by mild hydrothermal method and characterized by single-crystal X-ray diffraction and magnetization measurement.AgCu（IO3）3 is triclinic,space group P1,with a = 7.3081（1）,b = 7.8089（1）,c = 8.2447（1）A,α = 67.159（1）,β = 74.982（1）,γ = 80.982（1）°,and Z = 2.AgCu（IO3）3 is isostructral with Ag Pb（IO3）3.The structure of Ag Cu（IO3）3 consists of CuO6 chain columns parallel to the c axis,formed by corner-sharing Cu（1） and Cu（2） octahedra and flanked by corner-sharing IO3 groups; these CuO6 columns are cross-linked into a three-dimensional framework through I–O and Ag–O bonds.I（1）,I（2） and I（3） are coordinated respectively with 3 oxygens on the same side to form trigonal pyramids confirming the presence of a stereochemically active lone pair of each I^5＋ cation.In the CuO6 chain columns,Cu（1）O6 and Cu（2）O6 octahedra are tetragonally distorted with four shorter bonds in the square planes and two longer apical bonds.Cu（1）O6 octahedra were corner sharing with Cu（2）O6 octahedra with a shorter Cu（1）–O（1） bond in the square planes and a longer apical Cu（2）–O（1） bond,which forms a Cu（1）–Cu（2） magnetic chain along the c direaction.Magnetization measurement shows weak antiferromagnetic property in low temperature range.Ag Cu（IO3）3 provides a new example of a quasi-one-dimensional magnetic system.

Approximation law for discrete-time variable structure control systems

Two approximation laws of sliding mode for discrete-time variable structure control systems are proposed to overcome the limitations of the exponential approximation law and the variable rate approximation law. By applying the proposed approximation laws of sliding mode to discrete-time variable structure control systems, the stability of origin can be guaranteed, and the chattering along the switching surface caused by discrete-time variable structure control can be restrained effectively. In designing of approximation laws, the problem that the system control input is restricted is also considered, which is very important in practical systems. Finally a simulation example shows the effectiveness of the two approximation laws proposed.

The structural analysis of protein sequences based on the quasi-amino acids code

Proteomics is the study of proteins and their interactions in a cell. With the successful completion of the Human Cenome Project, it comes the postgenome era when the proteomics technology is emerging. This paper studies protein molecule from the algebraic point of view. The algebraic system （∑, ＋, ＊） is introduced, where ∑ is the set of 64 codons. According to the characteristics of （∑, ＋, ＊）, a novel quasi-amino acids code classification method is introduced and the corresponding algebraic operation table over the set ZU of the 16 kinds of quasi-amino acids is established. The internal relation is revealed about quasi-amino acids. The results show that there exist some very close correlations between the properties of the quasi-amino acids and the codon. All these correlation relationships may play an important part in establishing the logic relationship between codons and the quasi-amino acids during the course of life origination. According to Ma F et al （2003 J. Anhui Agricultural University 30 439）, the corresponding relation and the excellent properties about amino acids code are very difficult to observe. The present paper shows that （ZU, ＋,×） is a field. Furthermore, the operational results display that the eodon tga has different property from other stop codons. In fact, in the mitochondrion from human and ox genomic codon, tga is just tryptophane, is not the stop codon like in other genetic code, it is the case of the Chen W C et al （2002 Acta Biophysiea Siniea 18（1） 87）. The present theory avoids some inexplicable events of the 20 kinds of amino acids code, in other words it solves the problem of ＇the 64 codon assignments of mRNA to amino acids is probably completely wrong＇ proposed by Yang （2006 Progress in Modern Biomedicine 6 3）.

Thermodynamically Revealing the Essence of Order and Disorder Structures in Layered Cathode Materials

Layered transition metal(TM) oxides are one of the most widely used cathode materials in lithium-ion batteries. The atomic configuration in TM layer of these materials is often known to be random when multiple TM elements co-exist in the layer(e.g. Ni, Co and Mn). By contrast, the configuration tends to be ordered if the elements are Li and Mn. Here, by using special quasi-random structures(SQS) algorithm, the essential reasons of the ordering in a promising Li-rich Mn-based cathode material Li2MnO3 are investigated. The difference of internal energy and entropy between ordered and disordered materials is calculated. As a result, based on the Gibbs free energy, it is found that Li2MnO3 should have an ordered structure in TM layer. In comparison, structures with Ni-Mn ratio of 2:1 are predicted to have a disordered TM layer, because the entropy terms have larger impact on the structural ordering than internal energy terms.

The Two-dimensional Electromagnetic Scattering from Periodic Chiral Structures and Its Finite Element Approximation

In this paper, we consider the electromagnetic scattering from periodic chiral structures. The structure is periodic in one direction and invariant in another direction. The electromagnetic fields in the chiral medium are governed by the Maxwell equations together with the Drude-Born-Fedorov equations. We simplify the problem to a two-dimensional scattering problem and we show that for all but possibly a discrete set of wave numbers, there is a unique quasi-periodic weak solution to the diffraction problem. The diffraction problem can be solved by finite element method. We also establish uniform error estimates for the finite element method and the error estimates when the truncation of the nonlocal transparent boundary operators takes place.

Life cycle detection of prestress in large prestressed reinforcement structures

To monitor the stress state of prestressed reinforcement in large reinforcement prestressed structure, two sensing structures, namely the direct spiral-winding structure and sawtooth modulated structure, were designed based on the ordinary communication optical fiber. The sensing theories were analyzed, and the experimental studies were also carried out. The quasi-distributed sensing system based on optical time domain reflective technology was established. The detection wavelength and spatial resolution were analyzed, and the estimation formula of maximal number of sensing point was also given. The results show that the system can realize the quasi-distributed test of measurand with single fiber, which helps to simplify the in-out wires. Moreover it can take on the important task of long-term and continuous monitoring of prestress, which helps to realize the life cycle detection of prestress, and play an important role in the estimating of bridge health state.

DISCRETE VARIABLE STRUCTURE CONTROL OF LINEAR TIME-INVARIANT SYSTEMS WITH TIME DELAY

A discrete variable structure control(DVSC) method for the linear time invariant systems with time delay was presented. The continuous time delay systems are first transformed into the standard discrete form which contains no time delay by augmenting the state variables. Then the switching surface is determined by using the ideal quasi sliding mode. As it is difficult for the state trajectory to reach the switching surface exactly, the reaching condition in the form of approach law is used to design the controller. The deduced switching surface and controller contain not only the current step of state feedback but also some former steps of controls. Stability analysis with and without time delay information is also investigated in this paper. Numerical simulation was carried out to demonstrate the effectiveness and feasibility of the presented control method.

Structure Mechanism of Ordinary Matter Mass Formation

The famous paradoxes of quantum mechanics are created by the fact that elementary particles exist as the alternation between two structural states with different properties. This leads to probabilistic behavior, uncertainty principle, quantum tunneling, etc. The alternation of states plays the role of the frequency generator or clock. But for the objective character of quantum interactions the length standard also should exist in nature. Such analog of the rule must be physically real and in direct sense have to participate in the of particles interactions. Just this is the main role of physical vacuum. For such role vacuum should have quasi-crystalline geometry structure. Its symmetry requires in standard views only one fundamental change. In the quasicrystalline structure of the vacuum, the virtual shells of the real particles and atomic nuclei are not diffuse “clouds”, as is assumed today. Virtual environments are clearly structured and rigidly quantised shells with the geometric structure similar to fullerenes. Such shells are forming for greater than 99% of the known substance mass. Virtual particles forming such shells belong to the group of bosons and probably are just Higgs bosons existing in the ordinary matter. Chemical fullerenes form a series of discrete geometric structures. In a similar manner virtual analogues of fullerenes form a series of discrete masses, which really exist in the nature as a set of elementary particles and atomic nuclei masses.

钢支撑-钢筋混凝土掉层框架结构抗震性能试验研究

为改善坡地钢筋混凝土(RC)掉层框架结构抗侧刚度分布的不均匀性,设计了一栋在上接地层设置钢支撑的RC掉层框架结构,按1/4比例提取其顺坡向中榀框架下部5层子结构为试验对象,开展钢支撑-RC掉层框架拟静力试验,观测试件的破坏过程,并对比RC掉层框架试验所得试件的破坏形态,分析试件滞回性能、延性和刚度退化等抗震性能指标。结果表明:试件的最终破坏是以第4层柱底混凝土压溃,梁端混凝土剥落、底部钢筋断裂,顶层柱顶混凝土剥落为标志。与RC掉层框架试验结果相比,钢支撑-RC掉层框架试件上接地柱的破坏明显减轻,柱端破坏分布也更为均匀,避免了掉层框架结构“半层破坏模式”的出现,改善了结构的耗能和抗地震倒塌能力。但试件上接地层相邻上一层的变形和破坏程度较大,应对该楼层的柱端进行适当的抗震加强;设置钢支撑后,试件的滞回曲线较为饱满,并具有良好的延性(正、负向加载的位移延性系数分别可达5.13、5.69),正负向加载的刚度退化曲线也趋于对称。

句法成分语气化的类型、成因与条件

文章研究现代汉语里句法成分的语气化现象,即句法成分或结构体的语气功能凸显而其句法与语义功能削减甚至丧失的现象。文章指出了句法成分语气化的特点与判别标准,描述了三类句法成分的语气化现象及其功能演化的成因与条件:“准情态副词”由句法成分原位演化形成,“准语气词”由小句合并形成,“语气化结构”由直接添加专用的语气成分形成。文章还对诱发句法成分语气化的诸因素做了分析与讨论。

基于相对拟牛顿法的自卫式欺骗干扰抑制算法

自卫式欺骗干扰与目标信号高度相似,且二者的到达角完全相同,传统的主瓣干扰抑制算法难以对其进行抑制。针对该问题,文中在极化单输入多输出(PSIMO)雷达系统下,提出一种基于相对拟牛顿法的盲源分离算法。该算法利用干扰和目标的极化特性差异,通过构建重叠子阵结构计算出联合自相关矩阵,并采用相对拟牛顿法估计出分离矩阵,从而将目标和干扰信号分离在不同的通道上,实现干扰抑制作用。仿真实验结果表明,该算法能够有效抑制自卫式欺骗干扰,且在低信噪比(SNR)和密集干扰场景下依然具有良好的干扰抑制性能,当输入SNR为-10 dB时,输出的目标检测概率仍可以达到51.6%,拥有较强的鲁棒性。

基于准自然实验方法的城市绿道暴露与居民心理健康的因果机制研究

【目的】城市绿色空间是影响居民心理健康的重要因素,城市绿道建设已被认为是有效的绿色空间干预措施之一,探究城市绿道与居民心理健康的因果机制,对于优化绿色空间规划布局、提升居民心理健康水平具有重要的理论意义。【方法】运用准自然实验方法,以体力活动变化量、生理健康变化量、情绪状况变化量为中介变量构建结构方程模型,分析城市绿道暴露与居民心理健康水平变化的因果机制。【结果】1)绿道暴露可直接显著影响居民心理健康水平,也可通过身体健康得分变化量、身体质量指数(BMI)变化量两个中介变量间接影响心理健康水平。2)绿道暴露仅能直接影响女性群体的心理健康得分变化量;并通过BMI变化量间接作用于女性心理健康,通过中高强度体力活动时间变化量和身体健康得分变化量作用于男性心理健康。【结论】揭示了绿道暴露与居民心理健康水平变化的多路径因果机制以及男性和女性群体中存在作用路径和中介变量的差异。未来可通过优化绿道可达性、差异化配套绿道公共服务设施等健康导向的绿道规划措施,促进居民心理健康水平的提升。

均匀磁场下二维拓扑绝缘体边缘态的多重Andreev反射研究

研究均匀磁场下的二维拓扑绝缘体在超导隧道结中的电压偏置约瑟夫森结的输运性质,电流-电压特性显示了马约拉纳束缚态的存在。在亚谐隙结构中,也可以观察到磁场对超导能隙的影响。研究结果表明,在S波超导体/正常金属/S波超导结的隧道谱中存在亚谐隙结构。透明度只影响超导结的零偏压电导值的大小,而不影响亚谐隙结构的位置。但是在磁场作用下,亚谐隙结构会发生变化,不再固定出现在特定位置。这一结果对应于拓扑螺旋态中超导和铁磁序之间的相互作用。

舱室内爆下舰船结构损伤的一种计算方法

为了评估舱室内爆多载荷耦合作用下舰船结构的损伤范围,设计了大尺度舱段模型,并开展了舱室内爆毁伤试验,试验后测量了舱室结构的破坏范围及破坏模式,分析了舱室内爆多载荷耦合作用下舰船结构的损伤机理,据此建立了舱室内爆下舰船结构损伤的计算方法。结果表明:(1)舱室内爆下形成的强冲击波载荷和准静态压力载荷可对舰船结构造成大范围的损伤,形成多种破坏模式;(2)舱室内爆下准静态压力载荷是舱室结构损伤破坏的主要毁伤元;(3)建立的舱室内爆载荷下结构损伤变形计算方法可同时考虑强冲击载荷和准静态压力载荷对结构的损伤破坏,理论计算结果与试验结果吻合较好。