分子动力学模拟不同入射能量的CH与碳氢薄膜的相互作用

本文使用分子动力学方法模拟低能CH与碳氢薄膜的相互作用,以探讨在核聚变过程中CH的再沉积行为及对面向等离子体材料性质变化的影响。选择的入射能量分别为0.3,1,5,10 eV。模拟结果表明随着入射能量的增加C原子与H原子的吸附率增加,且在入射能量大于CH离解能的情况下,同一能量下H原子的吸附率小于C原子的吸附率。随着入射能量的增加,薄膜的厚度增加,薄膜中含有Csp2的范围变宽,并且表面逐渐转变为Csp2表面。薄膜中的C主要以Csp3形式存在,其次是Csp2,几乎不含Csp1。通过统计薄膜中的CHx(x为1~4)发现CH占优势,其次是CH2,而CH4的量非常少。     

Planar Concave Grating Demultiplexer Fabricated on a Nanophotonic Silicon-on-Insulator Platform

We show that a nanophotonic silicon-on-insulator (SOI) platform offers many advantages for the implementation of planar concave grating (PCG) demultiplexers, as compared with other material systems. We present for the first time the design and measurement results of a PCG demultiplexer fabricated on a nanophotonic SOI platform using standard wafer scale CMOS processes including deep-UV lithography. Our PCG device has four wavelength channels with a channel spacing of 20 nm and a record-small footprint of 280times150 mum. The on-chip loss is 7.5 dB, and the crosstalk is better than -30 dB     

Active thermography setup updating for NDE: a comparative study of regression techniques and optimisation routines with high contrast parameter influences for thermal problems

An implementation of updating techniques similar to finite element updating in structural dynamics is developed for thermal material inspection using adaptive response surfaces to approximate experimental parameters. In general, thermal models contain high nonlinearities in their parameters, which influences updating accuracies. This is further investigated in this work. Several adaptive response surface regression methods are compared: interpolation, piecewise spline and polynomial regression functions. Next, the influence of the choice of optimisation parameters is discussed and compared with several global and local optimisation routines. Finally, a well-suited regression technique is investigated which transforms the dataset to a smaller, focused response model in each optimisation loop and delivers a proper regression accuracy. This results in data-reduction for the model to be optimised.     

Software sensors for bioprocesses

State estimation is a significant problem in biotechnological processes, due to the general lack of hardware sensor measurements of the variables describing the process dynamics. The objective of this paper is to review a number of software sensor design methods, including extended Kalman filters, receding-horizon observers, asymptotic observers, and hybrid observers, which can be efficiently applied to bioprocesses. These several methods are illustrated with simulation and real-life case studies.     

Total dose and displacement damage effects in a radiation-hardened CMOS APS

A 512/spl times/512 CMOS active pixel sensor (APS) was designed and fabricated in a standard 0.5-/spl mu/m technology. The radiation tolerance of the sensor has been evaluated with Co-60 and proton irradiation with proton energies ranging from 11.7 to 59 MeV. The most pronounced radiation effect is the increase of the dark current. However, the total ionizing dose-induced dark current increase is orders of magnitude smaller than in standard devices. It behaves logarithmically with dose and anneals at room temperature. The dark current increase due to proton displacement damage is explained in terms of the nonionizing energy loss of the protons. The fixed pattern noise does not increase with total ionizing dose. Responsivity changes are observed after Co-60 and proton irradiation, but a definitive cause has not yet been established.     

Chloride pitting and water chemistry control in cooling or boiler circuits

The effect of different anions (bicarbonate, phosphate, sulphate, hydroxyl) on the pitting corrosion by chloride ions has been investigated for a number of ferritic or austenitic steels and nickel alloys at different temperatures up to 175°C. For most of the alloys the normal order of inhibition is PO₄³ > SO₄^2- HCO₃, but some anomalies have been encountered for stainless steels at lower temperatures (<100°C), where the inhibitive action of SO₄^2- maybe more pronounced that the inhibition which can be obtained by adding equal amounts of phosphate. In the absence of strongly passivating alloying elements, such as chromium, high SO₄² concentrations may have a deteriorative effect. The same result may also be found under cathodic polarization conditions, where SO₄^2- and HCO₃ seem to stimulate reductive dissolution of the protective surface layer and may even cause some kind of pitting-type attack.     

Silicon-on-Insulator CWDM Power Monitor/Receiver With Integrated Thin-Film InGaAs Photodetectors

In this letter, we demonstrate a compact and cost-effective four-channel demultiplexer with integrated photodetectors for application in coarse wavelength-division-multiplexing systems. The device consists of a silicon-on-insulator planar concave grating (PCG) demultiplexer and heterogeneously integrated InAlAs-InGaAs metal-semiconductor-metal photodetectors, and has a footprint of only 0.1 mm² . The PCG and integrated photodetectors have a responsivity of 0.6 A/W for TE-polarized light. The integrated device has an optical crosstalk of -25 dB.     

Modelling of Vitamin C Degradation during Thermal and High-Pressure Treatments of Red Fruit

Vitamin C is known for its potent antioxidant properties. Since humans lack one of the final enzymes in the biosynthesis of this vitamin, they are dependent on dietary sources for their vitamin C needs. Strawberries are good sources of vitamin C, but the vitamin is unstable during food processing, and high temperatures have shown to induce rapid degradation. As an alternative preservation technique, high-pressure processing is investigated for its potential to achieve pasteurisation and sterilisation conditions at lower process temperatures and shorter treatment times compared to thermal processing. The objective of the present study was to examine quantitatively the effect of processing on vitamin C in strawberry and raspberry matrices by comparing thermal treatments (80–140 °C) to treatments at 700 MPa (60 °C, 90 °C and 110 °C). To this end, a mechanistic model was proposed and tested to fit the degradation of ascorbic acid (AA) and the consecutive formation and degradation of dehydroascorbic acid (DHAA). AA degradation followed a biphasic course: the aerobic reaction was fast and most important, while the anaerobic reaction was slow and only perceptible at temperatures of 120 °C and up. The oxidation of AA to DHAA was slower than the subsequent degradation of DHAA in the strawberry matrix; the opposite was true in the raspberry matrix. Both temperature and pressure enhanced the degradation of vitamin C. The proposed mechanistic model provided reasonably good fits to the experimental data, only to a lesser extent for the DHAA evolution during high-pressure processing.     

Formation of endohedral Ni@C60 and exohedral Ni-C60 metallofullerene complexes by simulated ion implantation

The interaction of thermal and hyperthermal Ni ions with gas-phase C₆₀ fullerene was investigated at two temperatures with classical molecular dynamics simulations using a recently developed interatomic many-body potential. The interaction between Ni and C₆₀ is characterized in terms of the Ni-C₆₀ binding sites, complex formation, and the collision and temperature induced deformation of the C₆₀ cage structure. The simulations show how ion implantation theoretically allows the synthesis of both endohedral Ni@C₆₀ and exohedral Ni-C₆₀ metallofullerene complexes.     

Treatment of root perforations with calcium hydroxide and SuperEBA cement: a clinical report

Complete nucleotide sequence of a plasmid isolated from Enterobacter agglomerans has been determined. The plasmid, called pPIGDM1, consists of 2495 base pairs. The analysis of its nucleotide sequence suggested that pPIGDM1 may be a ColE1-like replicon. We confirmed this hypothesis by constructing a pPIGDM1-derived plasmid harboring the cat gene (pBW4), which could be introduced into Escherichia coli cells, and demonstrating that pBW4 cannot replicate in the absence of the polA function and that its copy number is significantly decreased in the pcnB mutant. Like some other ColE1-type replicons (e.g., pBR322), pPIGDM1-derived plasmids can be amplified both by chloramphenicol method and in isoleucine-starved relA mutants but not in relA+ bacteria. Inactivation of the putative rom gene by insertion of an amplicillin-resistance gene resulted in significant increase in pPIGDM1-derived plasmid copy number in E. coli-despite the fact that amino acid sequence of the putative RNA 1 modulator (Rom) protein is only 55.7% identical to the ColE1 analog. The pPIGDM1-derived rom-like coding sequence is also homologous to the rom-like gene present in the Proteus vulgaris plasmid pPvul. We suggest to group all these gene products into a new family called ROMS (RNA one modulators). Since a pPIGDM1-derived plasmid is compatible with other ColE1-like replicons (pMB1-, p15A, RSF1030-, and CloDF13-derived) in E. coli, one may consider pPIGDM1 as a progenitor of new cloning vehicles compatible with most (if not all) of currently used plasmid vectors. Moreover, this plasmid may serve as a source of the new rom-like gene coding for a protein useful in investigation of RNA-protein interactions. A role for the pPIGDM1 plasmid in the host strain is not known.