Biomolecular screening with encoded porous-silicon photonic crystals

Strategies to encode or label small particles or beads for use in high-throughput screening and bioassay applications focus on either spatially differentiated, on-chip arrays or random distributions of encoded beads. Attempts to encode large numbers of polymeric, metallic or glass beads in random arrays or in fluid suspension have used a variety of entities to provide coded elements (bits)--fluorescent molecules, molecules with specific vibrational signatures, quantum dots, or discrete metallic layers. Here we report a method for optically encoding micrometre-sized nanostructured particles of porous silicon. We generate multilayered porous films in crystalline silicon using a periodic electrochemical etch. This results in photonic crystals with well-resolved and narrow optical reflectivity features, whose wavelengths are determined by the etching parameters. Millions of possible codes can be prepared this way. Micrometre-sized particles are then produced by ultrasonic fracture, mechanical grinding or by lithographic means. A simple antibody-based bioassay using fluorescently tagged proteins demonstrates the encoding strategy in biologically relevant media.     

Design on semiconductor coupled SAW convolver

This paper presents results of a design study on a semiconductor coupled surface acoustic wave (SAW) convolver in which bi-directionally propagating SAWs, on a piezoelectric substrate with a high coupling coefficient, couple with bonded semiconductor diodes through multistrips. To obtain convolution signals with a high efficiency, we adopted a diode-balanced bridge structure for the nonlinear operation. We also found that the tapping pitches of the multi-strip electrodes have robustness against operation frequency variation and temperature-dependent variation on the delay of the SAW. We verified the effectiveness of the device in. a circuit simulation and an experiment on a test circuit, which was fabricated by using an epitaxial lift-off film-bonding process.     

A Managerial Perspective on Electronic Commerce Development in Malaysia

This research investigates the development of electronic commerce in Malaysia. It reviews the nation's e-commerce readiness and surveys local firms, a majority of them small- and medium-sized enterprises (SMEs), on their Web presence and e-commerce initiatives, management, capabilities and performance. Overall, while e-commerce in Malaysia is in its formative phases, a majority of firms in the survey sample have progressed beyond brochureware into the interactions phase; few have reached the e-commerce phase but many are planning to. They are driven primarily by marketing considerations and have seen the greatest impact of e-commerce on their marketing and overall business operations. Taking the lead are SMEs in IT/Internet services and solutions that see great opportunities in the nation's need to build the foundation layers for its emerging Internet economy. Most reluctant and least satisfied to date are SMEs in manufacturing that find the business-to-business sector largely undeveloped. The government can take some credits for its leadership in addressing the barriers to e-commerce development but the most significant barriers falls squarely within the private sector's domain. They will have to be overcome by entrepreneurial talents and management foresight.     

Web interaction using very small Internet devices

Internet-enabled cell phones typically accommodate only three to 12 text lines, and their design emphasizes portability. Web interaction has, so far, been a secondary concern. For the most part, automated techniques to address the feature gap between the desktop and these phonetops rely on the notion of transducing-translating HTML and images into formats compatible with small devices, which typically cannot handle HTML content. The authors have developed a Web browsing model that supports navigation and action in separate interfaces, To demonstrate the model, they created m-Links, a middleware proxy system that retrieves Web documents using HTTP, lets users navigate and apply services to Web content, and delivers a suitable user interface to a variety of small Web-capable wireless devices.     

Analysis of spatial arrangement of particles in thin foil of Al-Al4C3 material

TEM images of thin foils with quasi-globular particles are examined by means of two methods of spatial statistics. The spatial arrangement of particle reference points is described by means of quadrat count statistics and by polygonal method (the analysis of the Voronoi mosaic generated by patterns of particle reference points). A good agreement between the both approaches is found, the polygonal method is more sensitive and its results are more conclusive.     

MEAN STRESS EFFECTS ON LOW CYCLE FATIGUE FOR A HIGH STRENGTH STEEL

Abstract— ASTM A723 Q & T steel with a yield strength and ultimate strength of 1170 and 1262 MPa respectively was evaluated for mean stress-strain effects under smooth specimen axial strain controlled low cycle fatigue conditions with strain ratios R of −2, −1, 0, 0.5 and 0.75. Cycles to failure ranged from 15 to 10⁵. Cyclic stress-strain response based upon half-life hysteresis loop peaks were similar for all R ratios. Mean stress relaxation occurred for R ≠−1 only when plastic strain amplitudes were present and this occurred above total strain amplitudes of 0.005. Thus, mean stress relaxation was completely dependent upon cyclic plasticity. Mean strains did not affect low cycle fatigue life unless accompanied by half-life mean stress. Tensile mean stress was detrimental and compressive mean stress was beneficial and these effects only occurred at strain ampltidues below 0.005. Three different mean stress models were used to evaluate the low cycle fatigue data and the SWT log-log linear model best represented the data. These results can be used with the local notch strain fatigue life prediction methodology.     

Offset-trimming bit-line sensing scheme for gigabit-scale DRAM's

A new offset-trimming bit-line sensing scheme is described which is suitable for gigabit-scale DRAM's. This sensing scheme can suppress the sensitivity degradation caused by the large electrical parameter variation of deep submicron transistors. The effective offset voltage dependence on trimming time is analyzed and verified with simulation results. As compared with a conventional direct sensing scheme, the proposed scheme shows remarkable improvement on the sensitivity. A test device was fabricated with a 0.25 μm CMOS technology and its measurement results indicate the successful operation of offset-trimming     

Memorization of "unrelated" word strings by young nonpsychotic schizophrenics.

Used multiple word lists with low contextual constraints to examine nonorganizational processes or "strategies" which might be operating in single-trial free recall by schizophrenics. Ss were 20 young nonpsychotic schizophrenics and 20 normal controls. The schizophrenics, as compared to the normals, showed limited storage capacities of the primary and secondary memories, vulnerability to intrusion, slow response time, inefficiency in utilizing stimulus contiguity for organization, and consequential recall deficit. These findings, with those from previous investigations, suggest that both organizational and nonorganizational dysfunctions may underlie the schizophrenics' poor performance. The possibility that nonorganizational processes may be integral parts of mnemonic organization is discussed. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prediction of thermal conductivity and electrical resistivity of porous metallic materials

Thermal conductivity and electrical resistivity of porous materials, including 304L stainless steel Rigimesh, 304L stainless steel sintered spherical powders, and OFHC sintered spherical powders at different porosities and temperatures are reported and correlated. It was found that the thermal conductivity and electrical resistivity can be related to the solid material properties and the porosity of the porous matrix regardless of the matrix structure. It was also found that the modified Wiedemann-Franz-Lorenz relationship is valid for the porous materials under consideration. For high conductivity materials, the Lorenz function and the lattice component of conductivity depend on the material and are independent of the porosity. For low conductivity, the lattice component depends on the porosity as well.