温压技术的应用、发展及其在我国的工业化前景

根据国内外粉末冶金零件市场的走势，论证了温压技术在我国工业化的重要性。综述并讨论了温压技术的应用及发展趋势。介绍了作者们开发的温压专用粉末加热装置和温压成形粉末冶金材料的性能，其成果为温压原材料及设备的国产化打下了基础。     

Optimal running and planning of a biomass-based energy production process

We propose mathematical programming models for solving problems arising from planning and running an energy production process based on burning biomasses. The models take into account different aspects of the problem: determination of the biomasses to produce and/or buy, transportation decisions to convey the materials to the respective plants, and plant site locations. Whereas the “running model” is linear, we propose two “planning models”, both of which are mixed-integer nonlinear programming problems. We show that a spatial branch-and-bound type algorithm applied to them is guaranteed to converge to an exact optimum in a finite number of steps.     

On the (Un)Reliability of TCP Connections: The Return of the End-to-End Argument

This paper discusses the dangers of relying solely on TCP reliability when implementing dependable computing systems, even when those systems are designed to work over a LAN environment. The discussion includes a real-life example from our recent experiences in developing such a system.     

A note on the average run length of cumulative sum control charts for count data

This note presents preliminary results on the average run length (ARL) of a Cumulative Sum Control Chart (CUSUM) used to monitor defects or counts, when the count distribution is Neyman Type-A. The ARL for this distribution is contrasted to the more customary Poisson model for counts or defects. We show that the ARL curve of a Neyman Type-A CUSUM always lies below the ARL curve of a Poisson CUSUM.     

Can Electron Transmission from Aza-Crown Ethers Contribute to Diels-Alder π-Facial Selectivity?

A pair of isodicyclopentafulvenes that carries an exocyclic phenyl group para-substituted with an aza-15-crown-5 or aza-18-crown-6 ring has been prepared. These molecules ( 5a and 5b ) and their respective NaClO₄ ( 11 ) and KSCN ( 12 ) complexes were examined for the extent of π-facial stereoselectivity operational during their Diels-Alder cycloaddition to (Z)-1,2-bis(phenylsulfonyl)ethylene ( 2 ) under conditions of high pressure. Whereas 5a and 5b engage in [4 + 2] condensation with a 2.5–3.1 preference for dienophile capture from the above-plane direction, their complexes show a substantially reduced tendency for doing so (14/13 = 1.2–1.4). However, this response goes contrary to those para-substituent effects previously observed. The linear correlation noted earlier conformed to an increased preference for above-plane cycloaddition to 2 as the para-substituent became progressively more electron-withdrawing. Probable reasons for this seemingly divergent behavior are presented.     

Acoustically Enhanced Water Mist Suppression of Heptane Fueled Flames

Recent research has shown that acoustics can be used to suppress flames from a liquid fuel source. The results of these experiments indicated that acoustics alone are insufficient to control flames beyond the incipient stage. Recent research has also shown that variations in the delivery of water mist to a fire can enhance the mist’s efficiency. Therefore, the addition of acoustics to water mist may be an effective means of enhancing an established fire protection technology. For the first time, acoustics and water mist have been combined and studied as a flame suppression strategy. A series of experiments were conducted that explored the potential for coupling acoustics with water mist as means of flame suppression. Heptane fueled flames were created from two different sized ceramic fiber wicks: 30 mm?×?50 mm with 5 mL of fuel, and 60 mm?×?100 mm with 20 mL of fuel. The flames were then exposed to water mist delivered at a constant rate, which was found to be incapable of suppressing the flames. Next, low frequency sound waves at 62 Hz and 80 Hz were used to suppress flames from both wicks, with each frequency being generated by a different resonator. Finally, acoustics from both resonators were combined with water mist, and used to suppress flames from both wicks. The results showed that a combination of acoustic waves and water mist suppressed the flames more effectively than each individual technique on its own. This finding opens the possibility of developing more efficient ways to use water mist technology.     

Integration of InGaP/GaAs/Ge triple‐junction solar cells on deeply patterned silicon substrates

We report preliminary results on InGaP/InGaAs/Ge photovoltaic cells for concentrated terrestrial applications, monolithically integrated on engineered Si(001) substrates. Cells deposited on planar Ge/Si(001) epilayers, grown by plasma‐enhanced chemical vapor deposition, provide good efficiency and spectral response, despite the small thickness of the Ge epilayers and a threading dislocation density as large as 10⁷/cm². The presence of microcracks generated by the thermal misfit is compensated by a dense collection grid that avoids insulated areas. In order to avoid the excessive shadowing introduced by the use of a dense grid, the crack density needs to be lowered. Here, we show that deep patterning of the Si substrate in blocks can be an option, provided that a continuous Ge layer is formed at the top, and it is suitably planarized before the metalorganic chemical vapor deposition. The crack density is effectively decreased, despite that the efficiency is also lowered with respect to unpatterned devices. The reasons of this efficiency reduction are discussed, and a strategy for improvement is proposed and explored. Full morphological analysis of the coalesced Ge blocks is reported, and the final devices are tested under concentrated AM1.5D spectrum. Copyright © 2016 John Wiley & Sons, Ltd.     

Antioxidative activities of bran extracts from twenty one pigmented rice cultivars

Ethanol–water (70:30, v/v) extracts from the bran of rice seeds from twenty one pigmented and one nonpigmented rice cultivars were evaluated for antioxidative activities using the following tests: inhibition of peroxidation of linoleic acid; inhibition of peroxidation of rabbit lipid erythrocyte membranes; reduction of potassium ferricyanide, and scavenging of superoxide anions and hydroxyl radicals. With some exceptions, extracts from the pigmented rice seeds had higher antioxidative activity than did the nonpigmented variety. The following pigmented cultivars had the highest antioxidative activities in all tests: Jumlalocal-1, Parnkhari 203, DZ78, LK1-3-6-12-1-1, and Elwee. A significant correlation was also noted between reducing power, inhibition of erythrocyte ghost membrane peroxidation, and superoxide anion and hydroxyl radical scavenging. The results suggest that: (a) ferricyanide reducing power might be a useful and simple index for large-scale evaluation of antioxidative potencies of natural products present in rice; (b) pigmented rice varieties with high antioxidative activities provide a source of antioxidants and a genetic resource to develop new health-promoting rice cultivars.     

Yeast vectors for the integration/expression of any sequence at the TYR1 locus

We have constructed new yeast vectors for targeted integration and conditional expression of any sequence at the Saccharomyces cerevisiae TYR1 locus which becomes disrupted. We show that vector integration is not neutral, causing prototrophy for tyrosine and auxotrophy for the vector's selectable marker (uracil or leucine, depending on the vector used). This feature allows a double screening of transformed yeast cells, improving the identification of colonies with the desired chromosomal structure. The GAL10 gene promoter has been added to drive conditional expression of cloned sequences. Using these vectors, chromosomal structure verification of recombinant clones is no longer necessary, since the noise of non-homologous recombination, as well as spontaneous reversion of the selected phenotype, can easily be identified. The ability of the vector to conditionally control gene expression has been confirmed using the gene for the green fluorescent protein (GFP) as a reporter.