Electronic Sensing of Aromatic Volatiles for Quality Sorting of Blueberries

An electronic sniffer using semi-conductor gas sensors that nondestructively measured aromatic volatile gas emissions from fruit was developed to assess blueberry quality. The sniffer detected soft and damaged fruit in packaged containers at a 5% level of damage and distinguished four of five fruit ripeness classes: (1) mature-green and green-pink; (2) blue-pink; (3) blue; and (4) ripe fruit. Sniffer response increased as fruit ripened, as did total concentration of aromatic volatiles. Sniffer response correlated with berry firmness, pH, titratable acidity, and color, and detected differences among 10 cultivars, as did impact response analysis. The electronic sniffer is rapid, nondestructive and may be used to sort and quality check for presence of unripe or damaged fruit in closed packs of fresh berries.     

高频脉冲电铸Ni-Co纳米复合块体微观结构分析

采用高频脉冲电铸工艺制备出了镍钴纳米复合块体材料，利用场发射扫描电镜、能谱和X射线衍射的方法，重点研究了复合块体沉积层的表面形貌、相结构和结晶取向。结果表明．高频率和润湿剂的添加对沉积层的细化有重要影响，高频脉冲电铸能够获得微观组织致密、均匀的复合块体材料。     

Unconventional Charge Density Wave Arising from Electron–Phonon Interaction

We report of a theoretical study on quasi-one dimensional unconventional charge density wave (UCDW) driven by electron–phonon interaction. Within mean field theory, we find that the wavevector dependence of the coupling leads to a momentum dependent single particle gap on the Fermi surface. The presence of small energy single particle excitations around the gap nodes significantly changes the optical conductivity compared to the conventional CDW result. In addition to that, the collective phase excitation arising from fluctuation of the order parameter leads to further qualitative changes of the conductivity and results in an effective mass that is nonmonotonic in temperature.      

利用阵列感应测井资料反演地层径向电导率

采用阵列感应测井仪测得的具有不同径向探测深度的5条电导率曲线完成了井中径向电导率分布反演。径向侵入剖面模型由冲洗带、原状地层和从冲洗带到原状地层的过渡带3部分组成。该侵入剖面模型较传统的仅由冲洗带和原状地层构成的台阶状侵入剖面模型更加接近地层径向侵入剖面的真实情况。与台阶状侵入剖面模型相对应的参数模型包括冲洗带电导率、原状地层电导率和侵入半径3个参数。而与含有过渡带的新侵入剖面模型相对应的参数模型除包括冲洗带电导率、原状地层电导率和过渡带中点半径外，还有一个反映过渡带电导率变化的指数N0根据反演得到的过渡带中点半径和指数N可以求出过渡带起点半径和过渡带终点半径。而且根据反演过程中采用的正演响应函数可以计算出任意径向深度处过渡带的电导率值。数值试验结果说明了该方法的正确性，实际资料处理结果说明了该方法的有效性。     

Thermal Conductivity Measurement of an Electron-Beam Physical-Vapor-Deposition Coating

An industrial ceramic thermal-barrier coating designated PWA 266, processed by electron-beam physical-vapor deposition, was measured using a steady-state thermal conductivity technique. The thermal conductivity of the mass fraction 7 % yttria-stabilized zirconia coating was measured from 100 °C to 900 °C. Measurements on three thicknesses of coatings, 170 μm, 350 μm, and 510 μm resulted in thermal conductivity in the range from 1.5 W/(m·K) to 1.7 W/(m·K) with a combined relative standard uncertainty of 20 %. The thermal conductivity is not significantly dependent on temperature.     

Crystalline Behavior and Magnetic Properties of Nd60Fe30-x Al10Cox（x = 0,5,10） Bulk Amorphous Alloys

Crystalline behavior and magnetic properties of Nd60Fe30-xAl10Cox( x = 0, 5, 10) bulk amorphous alloys were investigated by differential scanning calorimeter (DSC), X-ray diffraction (XRD) and the vibrating sample magnetometer (VSM). Neither glass transition nor supercooled liquid region before crystallization was observed for the as-cast Nd60Fe30-xAl10Cox ( x = 0,5,10) bulk amorphous alloys. The glass forming ability can be improved significantly by the addition of Co. The as-cast Nd60Fe30-xAl10Cox (x = 0,5,10) alloys show hard magnetic behavior. With the addition of Co content, intrinsic coercivity (iHc) increases while the saturation magnetization(σs) and remanence (σr) decrease. The Curie temperature for the as-cast Nd60Fe30-xAl10Cox alloys increases from 451 K for x =0 to 468 K for x = 10. Some pre-cipitation of crystalline phases does not affect the hard magnetic properties of Nd60Fe30-xAl10Cox(x = 0,5,10) alloys, while the hard magnetic behavior disappears quickly after the alloys being completely crystallized.     

考虑介质变形和长期导流能力的裂缝性气藏压裂产能模拟研究

在气藏开采过程中，由于孔隙压力的不断降低，使得介质变形而导致渗透率的变化，进而影响井的产量。针对这一问题，提出了各种流体与固体耦合的数值模拟模型。然而，对于裂缝性储层和多相渗流问题，流固耦合模型中许多参数不易获取，且求解难度很大，使得耦合模型存在一定的应用局限性。很少有文献在气井产能模拟时将介质变形和就地的长期导流能力加以综合考虑。文章考虑介质变形引起的天然裂缝渗透率的变化和裂缝导流能力随时间递减的影响，建立了裂缝性气藏压裂后气水两相渗流数学模型，推导出了数值计算模型；本模型易于编程求解，对于研究裂缝性气藏的渗流特征，特别是进行单井压后产能预测具有一定的实用意义。计算表明：不考虑介质变形和导流能力递减所预测的气产量偏高；目前普遍使用的气藏数值模拟软件中，假定渗透率、裂缝导流能力为常数，以致模拟计算结果比实际偏高。     

容量系数法估算平台上部设施重量

容量系数法是用于项目初期平台上部设施估重的一种方法。本文介绍了容量系数法的理论基础、数据建立和估算实例,并分析了该法的应用条件和造成误差的原因。     

An analysis of the electrical conductivity in BaSO4-added Ag2SO4 solid electrolyte system

The compositions (1 −x)Ag₂SO₄−(x)BaSO₄, wherex=0·01 to 0·6, were prepared by slow cooling of the melt. The extent of the solid solubility of Ba²⁺ in Ag₂SO₄ was determined by X-ray powder diffraction and scanning electron microscopy. The bulk conductivity of each sample was obtained using a detailed impedance analysis. The partial substitution of Ba²⁺ results in the enhancement of conductivity in compliance with the classical aliovalent doping theory. A simplistic model based on lattice distortion (expansion) due to partial substitution of Ag⁺ by the bigger Ba²⁺ has been considered to explain enhanced conductivity. Beyond solid-solubility limit (5·27 mole%) the BaSO₄-dispersed Ag₂SO₄ conductivity follows the usual trend seen in binary systems. An increase in conductivity in this case is discussed in the light of interfacial reactions and surface defect chemistry. The maximum conductivity in 20 mole% BaSO₄ dispersed Ag₂SO₄ is due to percolation threshold.