摘要：It has often been reported that, when building structures are subjected to near-fault earthquake ground motions, horizontal and vertical impulsive inputs may cause critical damage during the first few seconds. In practical design of building structures, however, the safety check, taking into account the effect of multi-component ground motions, is hardly conducted except the design of important structures such as high-rise buildings and nuclear power plants. Ftirthel＇more, it is not clear how the correlation of multi-component ground motions influences the actual safety of structures. In this paper, the detailed property of critical excitation is discussed in association with the relationship between the characteristics of ground motions and those of structures. The properties of various auto power spectral density （PSD） functions of the horizontal and vertical ground motions are investigated, and those of the critical cross PSD function of these two-directional ground motions are found by a devised algorithm in a feasible complex plane. A closed-form expression is derived from the critical relation of the auto PSD functions of the simultaneous inputs. This critical excitation method provides us with a new approach for earthquake-resistant design against the possible future earthquake which causes the critical damages to buildings.

摘要：Despite a continuing increase in the number of patients suffering from chronic kidney disease,currently available treatments for these patients,such as dialysis and kidney transplantation,are *** kidney is also a critical target organ vulnerable to the toxicity of various new drugs,and the lack of a reliable in vitro culture model imposes a severe limitation on drug *** the development of induced pluripotent stem cells(iPSCs)revolutionized strategies in biomedical fields,the complexity of the kidney imposed additional challenge to the application of this technology in kidney ***,the recent advancement in our understanding on the developmental origin of kidney progenitor cells and the mechanisms of their reciprocal induction and self-organization has boosted research in kidney *** since then has demonstrated that kidney organoids derived from iPSCs can serve as a useful model for drug discovery and toxicity screening,as well as for disease modeling,especially in combination with gene editing ***,attempts at kidney organoid implantation in animals have suggested their potential as an alternative source of kidney *** this review,we summarize recent progress on the generation of kidney organoids,as well as the obstacles that remain.

摘要：A numerical procedure for hydrodynamic redesign of the conventional vaned diffuser into the low solidity vaned diffuser by means of a real-coded genetic algorithm with Boltzmann, Tournament and Roulette Wheel selection is presented. In the first part, an investigation on the relative efficiency of the different real-coded genetic algorithm is carried out on a typical mathematical test function. The real-coded genetic algorithm with Boltzmann selection shows the best optimization performance compared to the Tournament and Roulette Wheel selection. In the second part, an approach to redesign the vaned diffuser profile is introduced. Goal of the optimum design is to search the highest static pressure recovery coefficient and low solidity vaned diffuser. The result of the low solidity vaned diffuser optimum design confirms that the efficiency and optimization performance of the real-coded Boltzmann selection genetic algorithm outperforms the other selection methods. A comparison between the designed low solidity vaned diffuser and original vaned diffuser shows that the diffuser pump with the redesigned low solidity vaned diffuser has the higher static pressure recovery and improved total hydrodynamic performance. In addition, the smaller outlet diameter of designed vaned diffuser tends to a more compact size of diffuser pump compared to the original diffuser pump. The obtained results also demonstrate the real-coded Boltzmann selection genetic algorithm is a promising optimization algorithm for centrifugal pumps design.

摘要：High-pressure ratio and wide operating range are highly required for compressors and blowers. The technical issue of the design is achievement of suppression of flow separation at small flow rate without deteriorating the efficiency at design flow rate. A numerical simulation is very effective in design procedure, however, cost of the numerical simulation is generally high during the practical design process, and it is difficult to confn＇m the optimal design which is combined with many parameters. A multi-objective optimization technique is the idea that has been proposed for solving the problem in practical design process. In this study, a Low Solidity circular cascade Diffuser （LSD） in a centrifugal blower is successfully designed by means of multi-objective optimization technique. An optimization code with a meta-model assisted evolutionary algorithm is used with a commercial CFD code ANSYS-CFX. The optimization is aiming at improving the static pressure coefficient at design point and at low flow rate condition while constraining the slope of the lift coefficient curve. Moreover, a small tip clearance of the LSD blade was applied in order to activate and to stabilize the secondary flow effect at small flow rate condition. The optimized LSD blade has an extended operating range of 114 % towards smaller flow rate as compared to the baseline design without deteriorating the diffuser pressure recovery at design point. The diffuser pressure rise and operating flow range of the optimized LSD blade are experimentally verified by overall performance test. The detailed flow in the diffuser is also confirmed by means of a Particle Image Velocimeter. Secondary flow is clearly captured by PIV and it spreads to the whole area of LSD blade pitch. It is found that the optimized LSD blade shows good improvement of the blade loading in the whole operating range, while at small flow rate the flow separation on the LSD blade has been successfully suppressed by the secondary flow e

摘要：We previously demonstrated that polypod-like structured DNA, or polypodna, constructed with three or more oligodeoxynucleotides （ODNs）, is efficiently taken up by immune cells such as dendritic cells and macrophages, depending on its structural complexity. The ODNs comprising the polypodna should bend to form the polypod-like structure, and may do so by adopting either a bend- type conformation or a cross-type conformation. Here, we tried to elucidate the orientation and bending of ODNs in polypodnas using atomic force microscopy （AFM）. We designed two types of pentapodnas （i.e., a polypodna with five pods） using 60- to 88-base ODNs, which were then immobilized on DNA origami frames. AFM imaging showed that the ODNs in the pentapodna adopted bend-type conformations. Tetrapodna and hexapodna also adopted bend-type conformations when they were immobilized on frames under unconstrained conditions. These findings provide useful information toward the coherent design of, and the structure-activity relationships for, a variety of DNA nanostructures.

摘要：针对LMS(Least Mean Square)阵列信号波束成形器延时精度低和结构复杂的缺点,提出了一种基于Lagrange插值的非整数延时滤波器算法。其本质是采用频域近似的原则,设计出一种小数延时滤波器,可以将数字信号直接延时小数倍采样周期,在精确延时专题中具有广泛用途。仿真实验表明,该滤波器可满足阵列信号波束成形中的各种延时精度要求。

摘要：半导体太赫兹量子级联激光器(THz QCL)是一种相干性好线宽窄的太赫兹辐射源,有潜力获得高的输出功率.采用基于非平衡格林函数(NEGF)方法的计算工具设计、生长、制备了基于砷化镓系材料的THz QCL.在10 K温度下,峰值功率达到270 mW,平均功率为2. 4 mW,单位面积的输出功率与已报道的最高值相当.采用NEGF方法对器件的温度变化特性做了详细的分析.

摘要：为查明稻田花岗岩的强度及变形之各向异性特征,从同一个较大岩块试样的3个相互垂直的方向采制圆柱形拉伸试样,对此进行单轴拉伸实验。结果表明,稻田花岗岩的抗拉强度和变形常数随拉应力的作用方向不同而发生明显变化。在与rift面相垂直的方向拉伸时,其强度和弹性模量都明显小于其他方向。而且,实验结果也表明,抗压强度的各向异性程度比其他各种物性指标的各向异性程度都要大。此外,还设计了一个新的试件安装方式,能够在拉伸过程的任何一个中间阶段非破坏地取下试件以对其进行显微观察等。用此方法,成功地取下一个超过峰值强度且未完全拉断的试件,并切取内部的切片进行显微观察。结果表明,由拉伸所形成的花岗岩中的裂纹主要穿过矿物粒子内部,并不沿着粒子边界延伸。

摘要：介绍一种使用Sawyer马达驱动的平台和表面编码器组成的精密定位系统．该平台包括一个台板和若干线性脉冲马达推动器．台板由防腐钢板制成,在其表面加工了齿牙．线性脉冲马达推动器靠空气支承悬浮在台板上,用以驱动平台．每一驱动器均由一个永久磁铁和两个驱动线圈组成,用以产生X向和Y向的平台驱动力．设计了一种表面编码器用以测量和控制平台的运动．一个正弦格栅装在台板上,一个传感组件装在平台驱动器上．在该传感组件中有三个光学传感器,用以测量三个分离点上的X和Y方向的位置,平台的θ_z向位置可以从传感器输出求得．开发了一种反馈控制系统用以控制平台运动．测量和反馈控制实验证明了该精密系统的可行性．

摘要：This article reviewed recent progresses in the design of a new class of chemical oscillators and developed a generic model that could qualitatively reproduce those photochemical oscillations seen in experiments. The two oscillators discussed in this report are based on the photolysis of 1,4-benzoquinone and its derivatives, in which external illumination is vital in initiating and sustaining the reaction processes. Nonlinear behavior in these two photocontrolled chemical oscillators are analyzed as a function of light intensity and the initial concentration of reagents including 1,4-benzoquinone, 1,4-hydroquinone, 2-methyl-1,4-benzoquinone, bromate, and sulfuric acid. A generic model proposed initially for the uncatalyzed bromate-aromatic compound reactions was modified here to account for the photolysis of 1,4-benzoquinone or 2-methyl-1,4-benzoquinone. The modified model qualitatively reproduced chemical oscillations and their dependence on light intensity.