EXAFS用于Ru置换的固-液相醇氧化催化剂的研究

对Ru置换的有效的固一液相醇氧化催化剂Ru—hydrotalcite、Ru—Co-Ce—CO3和Ru—spinels进行了EXAFS的对比研究，发现催化剂的活性组分均为单核的Ru。对比属于Ru—hydrotalcite类的两种催化剂Mg—Al—Ru—CO3和Co—Al—Ru—CO3，EXAFS的表征证实，后者由于Co替代Mg，Ru的氧化态升高，实验证实它的催化活性增加。对比属于Ru—spinel类的MnFe1．95Ru0．05O4和MnFe1．8Cu0．15Ru0．05O4催化剂，发现部分Cu替代Fe导致后者的催化活性增加，EXAFS也证实其中Ru的氧化态升高。而Ru—Co—Ce—CO3催化剂具有高的醇氧化活性的原因也是由于Ru的氧化态较高。由此可以证实，在这类Ru改性的催化剂中，Ru—O是反应的活性位，可有效地加速醇的氧化反应。     

Surface soil moisture estimation from the synergistic use of the (multi-incidence and multi-resolution) active microwave ERS Wind Scatterometer and SAR data

This paper presents an original methodology to retrieve surface (<5 cm) soil moisture over low vegetated regions using the two active microwave instruments of ERS satellites. The developed algorithm takes advantage of the multi-angular configuration and high temporal resolution of the Wind Scatterometer (WSC) combined with the SAR high spatial resolution. As a result, a mixed target model is proposed. The WSC backscattered signal may be represented as a combination of the vegetation and bare soil contributions weighted by their respective fractional covers. Over our temperate regions and time periods of interest, the vegetation signal is assumed to be principally due to forests backscattered signal. Then, thanks to the high spatial resolution of the SAR instrument, the forest contribution may be quantified from the analysis of the SAR image, and then removed from the total WSC signal in order to estimate the soil contribution. Finally, the Integral Equation Model (IEM, [IEEE Transactions on Geoscience and Remote Sensing, 30 (2), (1992) 356]) is used to estimate the effect of surface roughness and to retrieve surface soil moisture from the WSC multi-angular measurements. This methodology has been developed and applied on ERS data acquired over three different Seine river watersheds in France, and for a 3-year time period. The soil moisture estimations are compared with in situ ground measurements. High correlations (R² greater than 0.8) are observed for the three study watersheds with a root mean square (rms) error smaller than 4%.     

Continued development of the Nimbus/University of Pittsburgh (UOP) axial flow left ventricular assist system

Nimbus and the University of Pittsburgh (UOP) have continued the development of a totally implanted axial flow blood pump under the National Institutes of Health (NIH) Innovative Ventricular Assist System (IVAS) program. This 62 cc device has an overall length of 84 mm and an outer diameter of 34.5 mm. The inner diameter of the blood pump is 12 mm. It is being designed to be a totally implanted permanent device. A key achievement during the past year was the completion of the Model 2 pump design. Ten of these pumps have been fabricated and are being used to conduct in vitro and in vivo experiments to evaluate the performance of different materials and hydraulic components. Efforts for optimizing the closed loop speed control have continued using mathematical modeling, computer simulations, and in vitro and in vivo testing. New hydraulic blade designs have been tested using computational fluid dynamics (CFD) and flow visualization. A second generation motor was designed with improved efficiency. To support the new motor, a new motor controller fabricated as a surface mount PC board has been completed. The program is now operating under a formal QA system.     

利用合适的相干因子提高光刻仿真准确性(英文)

利用光刻仿真软件PROLITH,进行了掩模版空间成像的焦深(DOF)和光学临近效应的 仿真。理论上分析了照明光瞳相干因子定义法:10％能量法和10％-90％积分能量法,并发展了因 子矫正法。仿真中分别代入了这三种定义法得到的照明光瞳相干因子,通过比较这三种情况与代 入真实光瞳的仿真结果,发现利用因子矫正法定义真实照明光瞳的相干因子,比其它两种定义法 得到的仿真结果与真实结果最接近,从而提高了仿真的准确性。     

MRI study of bread baking: experimental device and MRI signal analysis

An oven dedicated to a magnetic resonance imager (MRI) was designed and constructed for continuous monitoring of the entire baking process. The general aim was to test whether response variables conventionally measured on bread loaves, such as temperature, density, and water loss, were consistent with those reported for similar products baked in classical convection ovens. MRI images acquired during baking are presented and discussed, emphasising the need to develop quantitative MRI methods allowing conversion of the MRI signal into one variable of interest, such as local density or local water content.     

Investigation of the nitrogen-nickel-titanium system: The isothermal section at 900 °C

Phase relations in the ternary system N-Ni-Ti have been established experimentally for the 900 °C isothermal section assisted by thermodynamic modeling. Phase equilibria are characterized by an appreciable amount of up to ≅11 at. % N dissolved in the octahedral interstices of the crystal structure of Ti₂Ni. Two-phase equilibria are formed at 900 °C among the pairs Ti₂N + Ti₂NiN_x, TiN_1-x + Ti₂NiN_x, TiN_1-x + TiNi_1-x, and TiN_1-x + Ni(Ti)_x. The investigation is based on X-ray powder diffraction, metallography, scanning electron microscopy, and electron probe microanalysis techniques on about 50 alloys, which were prepared by arc melting or high-frequency levitation melting of appropriate blends of Ti,Ni-powders with TiN used to introduce nitrogen. Key experiments related to the N solubility in the Ti₂Ni phase have been triggered by an interactively performed thermodynamic modeling. The experimental results are in fine agreement with the thermodynamic calculation.     

钢包化学加热中用非铝发热剂的试验研究

用试验测定几种发热剂对钢水升温处理时的升温幅度和升温速度，并分析了不同发热剂和发热剂加入量对钢水升温处理效果的影响。根据试验结果和钢包化学加热法的特点对硅系合金作非铝发热剂进行了评价。     

A silicone-coated nylon dressing reduces healing time in burned paediatric patients in comparison with standard sulfadiazine treatment: a prospective randomized trial

Mepitel is a new grid like silicone coated nylon dressing containing no additional biological compounds. We describe a prospective randomized pilot study comparing Mepitel to the standard silver sulfadiazine cream (Flamazine) dressing for the topical treatment of paediatric burns. Seventy-six children presenting within 24 h of injury with a non previously treated burn were randomly assigned to Mepitel treatment (group M) or Flamazine treatment (group F). Age, sex, surface area of burn and causal agent were noted at admission. The depth of the burn, cumulative number of dressings, presence or absence of a complete epithelial cover, infection, bleeding and allergy were noted at each dressing change. There were 41 children in group M and 35 children in group F. Five children were subsequently withdrawn from each group because they required skin grafting. Analysis of the above mentioned criteria showed no statistical difference between the two groups except for the healing time (group M: 7.58+/-3.12, group F: 11.26+/-6.02, p < 0.01) and the number of dressings (group M: 3.64+/-1.5, group F: 5.13+/-2.9, p < 0.05). Mepitel has proved to be an easy-to-remove dressing, adhering only to intact skin. The faster healing time found in the Mepitel group may be related to a direct effect of silicone on epithelial growth or to a decrease in surface-cell damage compared to the silver sulfadiazine group. This attractive product will be further assessed on a larger scale trial to confirm our observations.     

Finite element formulation for inflatable beams

The discretized nonlinear equations for bending and buckling of inflatable beams are written by use of the virtual work principle with Timoshenko's kinematics, finite rotations and small strains. The linearized equations around a pre-stressed reference configuration are then deduced, giving rise to a new inflatable beam finite element. The stiffness matrix contains the shear coefficient and the internal pressure. Use is made of the particular 3-node beam element to investigate the bending and the buckling of a cantilever beam, the deflection of a pinched torus and the buckling of a torus submitted to a radial compressive force. The numerical results obtained with the beam element are shown to be close to analytical and three-dimensional (3D) membrane finite element results. The validity of the numerical results is discussed, in connection with the concepts of the crushing force or the wrinkling pressure of the inflated beam.