High‐Pressure Thermal Sterilization: Food Safety and Food Quality of Baby Food Puree

The benefits that high‐pressure thermal sterilization offers as an emerging technology could be used to produce a better overall food quality. Due to shorter dwell times and lower thermal load applied to the product in comparison to the thermal retorting, lower numbers and quantities of unwanted food processing contaminants (FPCs), for example, furan, acrylamide, HMF, and MCPD‐esters could be formed. Two spore strains were used to test the technique; Geobacillus stearothermophilus and Bacillus amyloliquefaciens, over the temperature range 90 to 121 °C at 600 MPa. The treatments were carried out in baby food puree and ACES‐buffer. The treatments at 90 and 105 °C showed that G. stearothermophilus is more pressure‐sensitive than B. amyloliquefaciens. The formation of FPCs was monitored during the sterilization process and compared to the amounts found in retorted samples of the same food. The amounts of furan could be reduced between 81% to 96% in comparison to retorting for the tested temperature pressure combination even at sterilization conditions of F₀‐value in 7 min.     

Process and performance optimization by selective assembly of battery electrodes

The increasing demand for electric vehicles and thus lithium-ion batteries results in a multitude of challenges in production technology. The reproducibility and performance of large scale batteries for automotive applications are very high. At the same time the production processes are complex and involve many uncertainties. Two essential process steps are the electrode coating and electrode package assembly. The mass loading of anodes and cathodes are determined by the coating process, where deviations can be caused by different reasons. The selective assembly of the electrodes is a reasonable way to balance the production variances. The contribution shows extended algorithms and their benefits and drawbacks of matching electrodes in order to improve the subsequent electrode packaging process. Here, the aim is to reach higher cell capacities and optimized performance values by “optimally” balanced electrodes regarding the mass loading ratio, which is also related to the specific material capacity.     

Gallium gradients in Cu(In,Ga)Se2 thin‐film solar cells

The gallium gradient in Cu(In,Ga)Se₂ (CIGS) layers, which forms during the two industrially relevant deposition routes, the sequential and co‐evaporation processes, plays a key role in the device performance of CIGS thin‐film modules. In this contribution, we present a comprehensive study on the formation, nature, and consequences of gallium gradients in CIGS solar cells. The formation of gallium gradients is analyzed in real time during a rapid selenization process by in situ X‐ray measurements. In addition, the gallium grading of a CIGS layer grown with an in‐line co‐evaporation process is analyzed by means of depth profiling with mass spectrometry. This gallium gradient of a real solar cell served as input data for device simulations. Depth‐dependent occurrence of lateral inhomogeneities on the µm scale in CIGS deposited by the co‐evaporation process was investigated by highly spatially resolved luminescence measurements on etched CIGS samples, which revealed a dependence of the optical bandgap, the quasi‐Fermi level splitting, transition levels, and the vertical gallium gradient. Transmission electron microscopy analyses of CIGS cross‐sections point to a difference in gallium content in the near surface region of neighboring grains. Migration barriers for a copper‐vacancy‐mediated indium and gallium diffusion in CuInSe₂ and CuGaSe₂ were calculated using density functional theory. The migration barrier for the In_Cu antisite in CuGaSe₂ is significantly lower compared with the Ga_Cu antisite in CuInSe₂, which is in accordance with the experimentally observed Ga gradients in CIGS layers grown by co‐evaporation and selenization processes. Copyright © 2014 John Wiley & Sons, Ltd.     

大型X射线光学仪器:单层镜和多层镜的制造与表征

150~500 mm长度的各种X射线光学元件可用于光束导引,光束调整,以及单色化。本文介绍了两种不同的大型X射线反射镜。第一种为单层反射镜,这种反射镜以2°掠入射角在软X射线区(50~200 eV)起全反射镜作用,可用于自由电子激光器,如德国汉堡的FLASH。第二种是多层镜,由于它的布喇格反射特性,适于作为反射镜以0.4~1°的入射角用于硬X射线区(20~50 keV),如层析光束线的同步辐射存储环中。两种反射镜都用最新物理汽相淀积法制备,并用磁控溅射来实现X射线光学应用所需要的优良光学品质。这一淀积工艺使不同批次的镀膜稳定性良好,有利于实际反射镜在优质衬底上的最后淀积。单层镜和多层镜在它们的相关能量范围内都有很高的反射率,表面粗糙度也很低,且在整个光学波长区这些特性表现均匀。文中所叙相关研究都是借助X射线反射计量(XRR)法,透射电子显微镜(TEM)、光学轮廓仪(OP),以及原子力显微镜(AFM)完成的。     

Pre-Transplant Serum Leptin Levels and Relapse of Acute Myeloid Leukemia after Allogeneic Transplantation

Weight loss and metabolic activity influence outcome after allogeneic stem cell transplantation (alloSCT). This study evaluates pre-conditioning Leptin, a peptide hormone involved in metabolism and immune homeostasis, as a prognostic factor for survival, relapse and non-relapse mortality (NRM) following alloSCT. Leptin serum levels prior to conditioning were determined in a cohort of patients transplanted for various hematologic malignancies (n = 524) and correlated retrospectively with clinical outcome. Findings related to patients with acute leukemia (AL) from this sample were validated in an independent cohort. Low pre-conditioning serum Leptin was an independent prognostic marker for increased risk of relapse (but not of NRM and overall mortality) following alloSCT for AL of intermediate and advanced stage (beyond first complete remission). Multivariate analysis revealed a hazard ratio (HR) for relapse of 0.75 per log2 increase (0.59–0.96, p = 0.020). This effect was similar in an independent validation cohort. Pre-conditioning serum Leptin was validated as a prognostic marker for early relapse by fitting the multivariate Cox model to the validation data. Pre-conditioning serum Leptin levels may serve as an independent prognostic marker for relapse following alloSCT in intermediate and advanced stage AL patients. Prospective studies are required to prove whether serum Leptin could be used for guiding nutritional intervention in patients with AL undergoing alloSCT.     

数字PID控制算法在冷水机组控制系统中的应用

通过对SIMATICStep-7编程软件中PID功能模块SFB41的参数分析与设定,并结合冷水机组控制系统的固有特点来实现多种数字PID控制算法的改进和冷凝压力的优化控制。     

Gelatinization of Starch During Preparation of Indian Unleaved Flat Breads

The comparison of starch granule deformation and extent of starch gelatinization in a few common Indian unleavened flat breads (Chapati, Parontha and Poorie) was made. The starch granule swelling was evaluated by scanning electron as well as polarized light microscopy. The peak viscosity in Haake rotary viscosimeter and hydration capacity were used for comparing the extent of starch gelatinization in crust and crumb of these baked products. Although a few of the starch granules on the outside of crust, maintained a weak outline those in the crumb area gave only a matrix of gelatinized starch. The extent of starch gelatinization was reflected by the related increase in hydration capacity of these products. However, the peak viscosity values were found to be inversely related to the extent of starch gelatinization. As compared to crumb, a higher extent of browning was observed in the crust. Water absorption, type of cereal, mode and efficiency of heat transfer were found to control the extent of starch gelatinization in these baked products.     

Topotaxial Formation of Mg4Nb2O9 and MgNb2O6 Thin Films on MgO (001) Single Crystals by Vapor–Solid Reaction

Thin-film solid-state reactions in the system MgO–Nb₂O₅ are experimentally investigated. MgO (001) substrates are subjected to Nb-O vapor at different temperatures in high vacuum. Thin films containing the phases Mg₄Nb₂O₉ and MgNb₂O₆ are formed by a vapor–solid reaction between the Nb-O vapor and the substrate. The crystallographic orientations of these phases are studied by X-ray diffractometry including pole figure analysis. Mg₄Nb₂O₉ grows (11.4)-, (11.6)-, and (11.9)-oriented, whereas MgNb₂O₆ grows with a preferential (241) orientation. The crystallographic relationships and their origins are discussed.