摘要：We developed a scheme based on wood surface novel wood recognition spectral features that aimed to solve three problems. First was elimination of noise in some bands of wood spectral reflection curves. Second was improvement of wood feature selection based on analysis of wood spectral data. The wood spectral band is 350-2500 nm, a 2150D vector with a spectral sampling interval of 1 nm. We developed a feature selection proce- dure and a filtering procedure by solving the eigenvalues of the dispersion matrix. Third, we optimized the design for the indoor radian＇s mounting height. We used a genetic algorithm to solve the optimal radian＇s height so that the spectral reflection curves had the best classification infor- mation for wood species. Experiments on fivecommon wood species in northeast China showed overall recogni- tion accuracy 〉95 % at optimal recognition velocity.

摘要：Hypoxia is a typical feature of the tumor microenvironment,one of the most critical factors affecting cell behavior and tumor ***,the lack of tumor models able to precisely emulate natural brain tumor tissue has impeded the study of the effects of hypoxia on the progression and growth of tumor *** study reports a three-dimensional(3D)brain tumor model obtained by encapsulating U87MG(U87)cells in a hydrogel containing type I *** also documents the effect of various oxygen concentrations(1%,7%,and 21%)in the culture environment on U87 cell morphology,proliferation,viability,cell cycle,apoptosis rate,and ***,it compares two-dimensional(2D)and 3D *** comparison purposes,cells cultured in flat culture dishes were used as the control(2D model).Cells cultured in the 3D model proliferated more slowly but had a higher apoptosis rate and proportion of cells in the resting phase(G0 phase)/gap I phase(G1 phase)than those cultured in the 2D ***,the two models yielded significantly different cell ***,hypoxia(e.g.,1%O2)affected cell morphology,slowed cell growth,reduced cell viability,and increased the apoptosis rate in the 3D *** results indicate that the constructed 3D model is effective for investigating the effects of biological and chemical factors on cell morphology and function,and can be more representative of the tumor microenvironment than 2D culture *** developed 3D glioblastoma tumor model is equally applicable to other studies in pharmacology and pathology.

摘要：Backfill hydraulic support is the key equipment in achieving coal mining and solid backfilling simultaneously in solid backfill mining *** on the summary and analysis of main types,basic structural properties and filed application of backfill hydraulic support,this work has firstly proposed the basic principle of backfill hydraulic support optimization design and provided the method of optimal design of key structural components,like four-bar linkage,rear canopy and tamping structure;the method is further elaborated as changing hinging position of upper bar to optimize four-bar linkage,by lengthening or shortening the rear canopy to optimize length ratio of canopy;and by changing length and hinging position of tamping structure as well as suspension height of backfill scrape conveyor to realize optimization of tamping *** this basis,the process of optimal design of backfill hydraulic support is *** optimal design case of ZC5200/14.5/30 six columns-four bar linkage used in 7203 W workface of Zhaizhen Coal Mine shows that the backfill properties like horizontal roof gap,vertical horizontal gap,tamping angle and tamping head gap are improved obviously through optimizing four-bar linkage,canopy length and tamping structure according to the optimal design method proposed in this work.

摘要：Contextual advertising is a major revenue source for today＇s companies. Keyword extraction is a key step in this kind of advertising, through which appropriate advertising keywords are extracted from Web pages so that corresponding ads can be triggered. This paper describes a system that learns how to extract keywords from web pages for advertisement targeting. Firstly a text network for a single webpage is build, then PageRank is applied in the network to decide on the importance of a word, finally top-ranked words are selected as keywords of the webpage. The algorithm is tested on the corpus ofblog pages, and the experimental results prove practical and effective.

摘要：This paper presents an extended object model for case-based reasoning （CBR） in product configuration design. In the extended object model, a few methods of knowledge expression are adopted, such as constraints, rules, objects, etc. On the basis of extended object model, case representation model for CBR is applied to product configuration design system. The product configuration knowledge can be represented by the extended object. The model can support all the processes of CBR in product configuration design, such as case representation, indexing, retrieving, and case revising. The presented model is an extension of the traditional object-oriented model by including the relationship class used to express the relation between the cases, constraints class used in the product configuration knowledge representation, index class used in ease retrieving, and solution class used in case revising. Therefore, the product configuration knowledge used in the product configuration design can be represented by using this model. In the end, a metering pump product configuration design system is developed on the basis of the proposed product configuration model to support customized products.

摘要：In this paper, high density of dislocations, grain boundaries and nanometer-scale α precipitates were intro- duced to a metastable Ti-36Nb-5Zr alloy （wt%） through a thermo-mechanical approach including severe cold rolling and short-time annealing treatment. The martensitic trans- formation was retarded, and the β phase with low content of β stabilizers was retained at room temperature after the thermo-mechanical treatment. As a result, both low mod- ulus （57 GPa） and high strength （950 MPa） are obtained. The results indicate that it is a feasible strategy to control martensitic transformation start temperature through microstructure optimization instead of composition design, with the aim of fabricating low modulus β-type Ti alloy.

摘要：The paper presented topology optimization of 2 D and 3 D Nanofluid-Cooled Heat Sink(NCHS). The flow and heat transfer problem in the NCHS was treated as a single-phase nanofluid based convective heat transfer model. The temperature-dependent fluid properties were taken into account in the model due to the strong temperature-dependent features of nanofluids. An average temperature minimum problem was studied subject to the fluid area and energy dissipation constraints by using the density method. In the method, the design variable is updated according to the gradient information obtained by an adjoint based sensitivity analysis process. The effects of the energy dissipation constraint, temperature-dependent fluid properties and nanofluid characteristics on optimal configurations of NCHS were numerically investigated with following ***, branched flow channels in the optimal configuration increased with the rise of the allowed energy dissipation. Secondly, temperature-dependent fluid properties were significant for obtaining the appropriate optimal results with best cooling performance. Thirdly, heat transfer performances of optimal configurations were enhanced by reducing the nanoparticle diameter or increasing the nanoparticle volume fraction. Fourthly, the optimal configuration for nanofluid had better cooling performance than that for its base fluid.

摘要：Electrochemical machining (ECM) is an effective and economical manufacturing method for machining hard-to-cut metal materials that are often used in the aerospace field. Cathode design is very complicated in ECM and is a core problem influencing machining accuracy, especially for complex profiles such as compressor blades in aero engines. A new cathode design method based on iterative correction of predicted profile errors in blade ECM is proposed in this paper. A mathematical model is first built according to the ECM shaping law, and a simulation is then carried out using ANSYS software. A dynamic forming process is obtained and machining gap distributions at different stages are analyzed. Additionally, the simulation deviation between the prediction profile and model is improved by the new method through correcting the initial cathode profile. Furthermore, validation experiments are conducted using cathodes designed before and after the simulation correction. Machining accuracy for the optimal cathode is improved markedly compared with that for the initial cathode. The experimental results illustrate the suitability of the new method and that it can also be applied to other complex engine components such as diffusers. (C) 2016 Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics.

摘要：New solid backfill mining technology provides unique technical advantages for ‘‘three-under'' coal mining which refers to coal resources trapped under buildings, railways, and water bodies. This technology has a much higher recovery rate and can effectively control the surface subsidence. However, successful application of this technology depends heavily on geological conditions. To avoid the disadvantages associated with downward mining and overhead backfilling with this new technology, a new advanced solid backfill mining design with two pre-driving entries is proposed here to ensure the backfill effect. Taking Huayuan coal mine as an example, this paper tests the double gob-side entries retaining with no pillar left scheme and optimizes an integrated technology setup for backfill mining and gob-side entry retaining. Field applications show that the recovery rate increased from 40% for strip mining to 85% for backfill mining. Moreover, the new backfill technology allowed for better control over the surrounding rock deformation caused by the gob-side entry retaining effect and better control of ground subsidence as compared to strip mining.

摘要：We report the design of a novel multiband metamaterial bandpass filter （BPF） in the terahertz （THz）-wave region. The designed BPF is composed of a metal-dielectric-metal sandwiched structure with three nested rings on the top surface and a cross structure on the bottom surface. Full-wave simulation results show that the designed BPF has three transmission peaks at frequencies of 0.42, 1.27, and 1.86 THz with transmission rates of-0.87,-1.85, and-1.83 dB, respectively. Multi-reflection interference theory is introduced to explain the transmission mechanism of the designed triple-band BPF. The theoretical transmission spectrum is in good agreement with the full-wave simulated results. The designed BPF can maintain a stable performance as the incident angle varies from 0 to 30 for both transverse electric and transverse magnetic polarizations of the incident wave. The designed BPF can be potentially used in THz devices due to its multiband transmissions, polarization insensitivity, and stable wide-angle response in the THz region.