发动机振动主动控制用电磁作动器的设计和动态特性研究

对一种适用于汽车发动机振动主动控制用的新型串接式高能电磁作动器进行了结构设计,计算了作动器的磁场,对作动器的片状弹簧的应力分布进行了有限元分析。同时,建立了作动器的力学模型,对其动态特性进行了仿真分析和试验研究,结果表明作动器是理想的激振源和主动控制用作动器。     

On-chip natural assembly of silicon photonic bandgap crystals.

Photonic bandgap crystals can reflect light for any direction of propagation in specific wavelength ranges. This property, which can be used to confine, manipulate and guide photons, should allow the creation of all-optical integrated circuits. To achieve this goal, conventional semiconductor nanofabrication techniques have been adapted to make photonic crystals. A potentially simpler and cheaper approach for creating three-dimensional periodic structures is the natural assembly of colloidal microspheres. However, this approach yields irregular, polycrystalline photonic crystals that are difficult to incorporate into a device. More importantly, it leads to many structural defects that can destroy the photonic bandgap. Here we show that by assembling a thin layer of colloidal spheres on a silicon substrate, we can obtain planar, single-crystalline silicon photonic crystals that have defect densities sufficiently low that the bandgap survives. As expected from theory, we observe unity reflectance in two crystalline directions of our photonic crystals around a wavelength of 1.3 micrometres. We also show that additional fabrication steps, intentional doping and patterning, can be performed, so demonstrating the potential for specific device applications.     

Superconductivity in CaCuO2 as a result of field-effect doping.

Understanding the doping mechanisms in the simplest superconducting copper oxide-the infinite-layer compound ACuO2 (where A is an alkaline earth metal)-is an excellent way of investigating the pairing mechanism in high-transition-temperature (high-Tc) superconductors more generally. Gate-induced modulation of the carrier concentration to obtain superconductivity is a powerful means of achieving such understanding: it minimizes the effects of potential scattering by impurities, and of structural modifications arising from chemical dopants. Here we report the transport properties of thin films of the infinite-layer compound CaCuO2 using field-effect doping. At high hole- and electron-doping levels, superconductivity is induced in the nominally insulating material. Maximum values of Tc of 89 K and 34 K are observed respectively for hole- and electron-type doping of around 0.15 charge carriers per CuO2. We can explore the whole doping diagram of the CuO2 plane while changing only a single electric parameter, the gate voltage.     

The origin of spontaneous activity in the developing auditory system

Spontaneous activity in the developing auditory system is required for neuronal survival as well as the refinement and maintenance of tonotopic maps in the brain. However, the mechanisms responsible for initiating auditory nerve firing in the absence of sound have not been determined. Here we show that supporting cells in the developing rat cochlea spontaneously release ATP, which causes nearby inner hair cells to depolarize and release glutamate, triggering discrete bursts of action potentials in primary auditory neurons. This endogenous, ATP-mediated signalling synchronizes the output of neighbouring inner hair cells, which may help refine tonotopic maps in the brain. Spontaneous ATP-dependent signalling rapidly subsides after the onset of hearing, thereby preventing this experience-independent activity from interfering with accurate encoding of sound. These data indicate that supporting cells in the organ of Corti initiate electrical activity in auditory nerves before hearing, pointing to an essential role for peripheral, non-sensory cells in the development of central auditory pathways.     

χ2拟合检验法在成绩分析中的应用

以考试成绩为样本观察值,运用实用的拟合检验法进行统计,设计一种易于实现的量化处理过程,完成对考试成绩客观准确的分析,为教育质量监控和评价提供有效的保障.     

日本有机薄膜太阳能电池研究进展

通过调查近两年的最新文献资料,综述了有机太阳能电池的优劣和国际研究现状.从多个侧面阐述了日本有机太阳能研究现状,并探讨了今后有机薄膜器件研究的发展趋势和走向.     

确定SIMPLE算法中压力松弛因子的自适应方法

压力松弛因子的选取是SIMPLE(Swrni-Implicit Method for Pressure-Linked Equations,SIMPLE)算法在数值求解流体流动及对流换热问题的难点之一.针对非稳态流动问题,提出了一种SIMPLE算法中压力松弛因子的自适应方法,有效地避免了松弛因子对计算结果的影响.通过对两...     

An integrated semiconductor device enabling non-optical genome sequencing

The seminal importance of DNA sequencing to the life sciences, biotechnology and medicine has driven the search for more scalable and lower-cost solutions. Here we describe a DNA sequencing technology in which scalable, low-cost semiconductor manufacturing techniques are used to make an integrated circuit able to directly perform non-optical DNA sequencing of genomes. Sequence data are obtained by directly sensing the ions produced by template-directed DNA polymerase synthesis using all-natural nucleotides on this massively parallel semiconductor-sensing device or ion chip. The ion chip contains ion-sensitive, field-effect transistor-based sensors in perfect register with 1.2 million wells, which provide confinement and allow parallel, simultaneous detection of independent sequencing reactions. Use of the most widely used technology for constructing integrated circuits, the complementary metal-oxide semiconductor (CMOS) process, allows for low-cost, large-scale production and scaling of the device to higher densities and larger array sizes. We show the performance of the system by sequencing three bacterial genomes, its robustness and scalability by producing ion chips with up to 10 times as many sensors and sequencing a human genome.