热熔加热板的解耦频率整形滑模控制方法研究

文章将频率整形滑模控制和解耦系统相结合用于耦合热熔加热板的控制。控制对象为一个底部分布5个加热器的加热板,控制目的为快速稳定地到达指定温度并且实现板面温度的统一。滑模控制方法具有良好的鲁棒性和优秀的抗干扰能力,在控制多输入多输出(multiple-input multiple-output,MIMO)耦合系统时,控制性能良好。但是在其控制过程当中,抖振问题的存在使得系统存在潜在的危险。该文使用基于最优控制原理的频率整形滑模控制,使得系统抖振行为得以有效地减弱。同时由于系统处于耦合状态,该文提出了解耦系统与频率整形滑模控制相结合,通过前馈补偿矩阵,减小系统耦合程度,使得系统获得更好的动态特性的方法。最后,仿真和实验结果验证所述方法的有效性和优越性。     

Fabrication of a TiO2-P25/(TiO2-P25+TiO2 nanotubes) junction for dye sensitized solar cells

The dye sensitized solar cell（DSSC）, which converts solar light into electric energy, is expected to be a promising renewable energy source for today’s world. In this work, dye sensitized solar cells, one containing a single layer and one containing a double layer, were fabricated. In the double layer DSSC structure, the under-layer was TiO₂-P25 film, and the top layer consisted of a mixture of TiO₂-P25 and TiO₂ nanotubes. The results indicated that the efficiency of the DSSC with the double layer structure was a significant improvement in comparison to the DSSC consisting of only a single film layer. The addition of TiO₂-P25 in the top layer caused an improvement in the adsorption of dye molecules on the film rather than on the TiO₂ nanotubes only. The presence of the TiO₂ nanotubes together with TiO₂-P25 in the top layer revealed the enhancement in harvesting the incident light and an improvement of electron transport through the film.     

Effect of SiO2 addition on the dielectric properties and microstructure of BaTiO3-based ceramics in reducing sintering

The effect of SiO₂ doping on the sintering behavior, microstructure, and dielectric properties of BaTiO₃-based ceramics has been investigated. Silica was added to the BaTiO₃-based powder prepared by the solid state method with 0.075mol%, 0.15mol%, and 0.3mol%, respectively. The SiO₂-doped BaTiO₃-based ceramic with high density and uniform grain size were obtained, which were sintered in reducing atmosphere. A scanning electron microscope, X-ray diffraction, and LCR meter were used to determine the microstructure as well as the dielectric properties. SiO₂ can form a liquid phase belonging to the ternary system of BaO-TiO₂-SiO₂, leading to the formation of BaTiO₃ ceramics with high density at a lower sintering temperature. The SiO₂-doped BaTiO₃-based ceramics can be sintered to a theoretical density higher than 95% at 1220℃ with a soaking time of 2 h. The dielectric constants of the sample with 0.15mol% SiO₂ addition sintered at 1220℃ is about 9000. Doping with a small amount of silica can improve the sintering and dielectric properties of BaTiO₃-based ceramics.     

爆轰波三波点擦除烟迹表面积碳机制

为理解三波点在壁面及端面积碳留下记录的确切机制,推动对螺旋爆轰内部结构的研究,采用端面烟熏玻璃与内壁烟膜结合的实验方法记录胞格结构,并得到不稳定、较稳定及稳定预混气的侧壁及端面爆轰记录.2H2+O2+3Ar给出了清晰精细的端面结果,其单头螺旋结果表明相对于结果近似的侧壁结果,内部螺旋结构并非固定.进而从附着碳粒的粒度尺寸分析出碳迹附着原理并结合五种预混气的反应特性,确定键能足以克服碳迹吸附在表面的力时才能擦除烟迹.另外预混气中的碳分子也会导致烟迹堆积而影响端面结果,反射激波的强度也影响记录的清晰度.最终确定烟迹擦除机制受预混气影响,应针对预混气选用表面粗糙度载体和积碳颗粒尺寸,并给出了记录爆轰结构的方法.     

Initial corrosion observed on the atomic scale

Corrosion destroys more than three per cent of the world's GDP. Recently, the electrochemical decomposition of metal alloys has been more productively harnessed to produce porous materials with diverse technological potential. High-resolution insight into structure formation during electrocorrosion is a prerequisite for an atomistic understanding and control of such electrochemical surface processes. Here we report atomic-scale observations of the initial stages of corrosion of a Cu3Au111 single crystal alloy within a sulphuric acid solution. We monitor, by in situ X-ray diffraction with picometre-scale resolution, the structure and chemical composition of the electrolyte/alloy interface as the material decomposes. We reveal the microscopic structural changes associated with a general passivation phenomenon of which the origin has been hitherto unclear. We observe the formation of a gold-enriched single-crystal layer that is two to three monolayers thick, and has an unexpected inverted (CBA-) stacking sequence. At higher potentials, we find that this protective passivation layer dewets and pure gold islands are formed; such structures form the templates for the growth of nanoporous metals. Our experiments are carried out on a model single-crystal system. However, the insights should equally apply within a crystalline grain of an associated polycrystalline electrode fabricated from many other alloys exhibiting a large difference in the standard potential of their constituents, such as stainless steel (see ref. 5 for example) or alloys used for marine applications, such as CuZn or CuAl.     

Mammalian cochlear supporting cells can divide and trans-differentiate into hair cells

Sensory hair cells of the mammalian organ of Corti in the inner ear do not regenerate when lost as a consequence of injury, disease, or age-related deafness. This contrasts with other vertebrates such as birds, where the death of hair cells causes surrounding supporting cells to re-enter the cell cycle and give rise to both new hair cells and supporting cells. It is not clear whether the lack of mammalian hair cell regeneration is due to an intrinsic inability of supporting cells to divide and differentiate or to an absence or blockade of regenerative signals. Here we show that post-mitotic supporting cells purified from the postnatal mouse cochlea retain the ability to divide and trans-differentiate into new hair cells in culture. Furthermore, we show that age-dependent changes in supporting cell proliferative capacity are due in part to changes in the ability to downregulate the cyclin-dependent kinase inhibitor p27(Kip1) (also known as Cdkn1b). These results indicate that postnatal mammalian supporting cells are potential targets for therapeutic manipulation.     

Design of child’s safety management system based on ontology using context information of home network

This paper presents a system to alert of dangerous a child situation of a child by applying context information collected from a home network to ontology that is capable of inference. Radio frequency Identification (RFID) and sensors were used for the configuration of a home network, to obtain the raw data to convert into context information. To express the ontology, web ontology language (OWL) was used to provide the inference of context information. Then, simple object access protocol (SOAP) messages were used to notify of the dangerous situations that a child may be involved in via mobile devices. The proposed system consists of Context Manager, Service Manager, and Notification Manager. The child's safety management system can proactively detect the context data of a child on the basis of context awareness. In the experiment, the Jena 2.0 by ontology reasoner and the OSGi(Open Service Gateway initiative) Gateway developed using open source software Knopflerfish 1.3.3 were used to implement the service frame work.     

Characterization and Preparation of Bimetallic Nanoparticles

1 Results Bimetallic particles in the nanometer size range are of substantial interest due to their vast applications in catalysis[1].The synthesis of bimetallic nanoparticles with definite size with a well-control over their nanostructure remains a challenging problem.Thus there exists a great demand for both synthesis and atomic level characterization of nanostructure of bimetallic nanoparticles (NPs).With the recent advent of high-intensity tunable sources of X-rays,now available at synchrotron radiation facilities worldwide,made X-ray absorption spectroscopy (XAS) a powerful tool for carrying out most of the structural aspects of the nano-sized catalysts.     

Active Cooling e-Textiles for Smart Clothing

Cooling function is definitely one of the most desirable attributes of clothing. In spite of the recent progress on phase changing material （PCM） research, the final products with sufficient amount of cooling capability have not yet to be developed in market. A new concept of cooling fabrics has been proposed by applying ＂Peltier effect＂ to textile materials. It occurs whenever electrical current flows through two dissimilar conductors t depending on the direction of current flow, the junction of the two conductors will either absorb or release heat. This effect has been tested on P-type and N-type conducting polymers. A P-type conductive polypyrrole coated fabric was synthesized by in- situ polymerization on plain weave PET to make conductive fabrics. And an N.typo electrically conductive material was synthesized by treatment of MWNT and polyethyleneimine （PEI）. A noticeable amount of temperature difference has been found in the fabric.     

追踪深海望远镜

爱隐居的望远镜"冰立方"微中子望远镜被冻在2000多米深的南极冰层下,而KM3微中子望远镜建在300多米深的地中海里。位于日本的微中子望远镜就藏在地底1000米深的神冈矿山下。加拿大安大略省的微中子望远镜被深埋在地底2000多米的人造水缸中。在充满阳光和沙滩的夏威夷,却也有微中子望远镜隐居在天然的山谷中。……望远镜贵在能望远,可这藏起来的望远镜要怎么望?隐士自有妙计。深藏不露,为的就是捉拿那些隐形的微中子杀手。