Prediction on hot deformation behavior of spray-formed 7055 aluminum alloy via phenomenological models

Hot compression tests in the temperature range of 340–450 °C and strain rate range of 0.001–1 s^?1 of spray-formed 7055 aluminum alloy were carried out to study its hot deformation behavior. Three phenomenological models including Johnson–Cook, modified Fields–Backofen and Arrhenius-type were introduced to predict the flow stresses during the compression process. And then, a comparative predictability of the phenomenological models was estimated in terms of the relative errors, correlation coefficient (R), and average absolute relative error (AARE). The results indicate that Johnson–Cook model and modified Fields–Backofen model cannot well predict the hot deformation behavior due to the large deviation in the process of line regression fitting. Arrhenius-type model obtains the best fit through combining the effect of strain rate and temperature.     

催化臭氧氧化处理渗滤液RO浓液的氧化特性及光谱分析

腐殖质的去除效率是催化臭氧氧化降解垃圾渗滤液RO浓液中有机物的关键,活性炭负载金属铈催化剂（Ce-AC）催化臭氧氧化可有效提高腐殖质的去除效率。本文通过XRD、SEM和EDS等手段对Ce-AC催化剂进行表征,对比不同催化剂催化臭氧氧化对RO浓液COD去除及可生化性的影响,通过降解产物光谱分析明晰腐殖质的降解机制。结果表明,铈氧化物是以CeO₂萤石晶型的形式负载在AC上,负载后的AC比表面积和孔容积减少,平均孔径增加。催化剂Ce-AC对COD和UV₂₅₄的去除效果最好,为44.7%和67.3%,出水可生化性显著提升,B/C比从0.06提升到0.47。紫外-可见光谱表明,体系代表腐殖质的芳香类化合物降解效率明显;三维荧光光谱表明体系中腐殖质类物质被极大程度地降解,荧光区域积分的结果表明腐殖质类物质的去除效率达到了66.7%;傅里叶红外光谱表明腐殖质类物质被氧化分解成了相对小分子的碳水化合物和有机胺、硫和醇等。     

Effect of Exogenous Auxin Treatment on Cell Wall Polymers of Strawberry Fruit

The role of auxin in the fruit-ripening process during the early developmental stages of commercial strawberry fruits (Fragaria x ananassa) has been previously described, with auxin production occurring in achenes and moving to the receptacle. Additionally, fruit softening is a consequence of the depolymerization and solubilization of cell wall components produced by the action of a group of proteins and enzymes. The aim of this study was to compare the effect of exogenous auxin treatment on the physiological properties of the cell wall-associated polysaccharide contents of strawberry fruits. We combined thermogravimetric (TG) analysis with analyses of the mRNA abundance, enzymatic activity, and physiological characteristics related to the cell wall. The samples did not show a change in fruit firmness at 48 h post-treatment; by contrast, we showed changes in the cell wall stability based on TG and differential thermogravimetric (DTG) analysis curves. Less degradation of the cell wall polymers was observed after auxin treatment at 48 h post-treatment. The results of our study indicate that auxin treatment delays the cell wall disassembly process in strawberries.     

Chronically Elevated Exogenous Glucose Elicits Antipodal Effects on the Proteome Signature of Differentiating Human iPSC-Derived Pancreatic Progenitors

The past decade revealed that cell identity changes, such as dedifferentiation or transdifferentiation, accompany the insulin-producing β-cell decay in most diabetes conditions. Mapping and controlling the mechanisms governing these processes is, thus, extremely valuable for managing the disease progression. Extracellular glucose is known to influence cell identity by impacting the redox balance. Here, we use global proteomics and pathway analysis to map the response of differentiating human pancreatic progenitors to chronically increased in vitro glucose levels. We show that exogenous high glucose levels impact different protein subsets in a concentration-dependent manner. In contrast, regardless of concentration, glucose elicits an antipodal effect on the proteome landscape, inducing both beneficial and detrimental changes in regard to achieving the desired islet cell fingerprint. Furthermore, we identified that only a subgroup of these effects and pathways are regulated by changes in redox balance. Our study highlights a complex effect of exogenous glucose on differentiating pancreas progenitors characterized by a distinct proteome signature.     

Theoretical and experimental studies of a new aniline derivative corrosion inhibitor for mild steel in acid medium

4-Chloro-N-(pyridin-2-ylmethyl)aniline (CPYA) was synthesized by a simple and inexpensive method and tested as a corrosion inhibitor in acid medium for mild steel by using gravimetric studies and electrochemical measurements. An average maximum efficiency of 96.0% was achieved at 4.59 mmol/L. Corrosion kinetic and thermodynamic parameters were also analyzed. Surface analyses (atomic force microscopy and scanning electron microscopy) show that protection is enabled by adsorption on the metal, forming a film. Quantum chemical calculations were performed to access information regarding the molecular structure in the corrosive medium and to support interpretation of the results obtained by experimental methods.     

概率距离在联机汉字识别中的应用

借助概率理论，将汉字信息看成随机事件，提出了概率距离的概念。概念距离依据事件的稳定性决定事件对识别距离的影响力，并以此为依据实现了在识别过程中的特征选择。经试验分析，有很好的效果，已将识别率提高了8个百分点。     

农村公路普及与规划深度发展预测

通过对农村公路通达深度的分析，提出了农村公路近期发展规模和资金需求预测，为指导农村路网规划提出参考依据。     

Multi-fidelity optimization of laminated conical shells for buckling

Optimum laminate configuration for minimum weight of filament-wound laminated conical shells is investigated subject to a buckling load constraint. In the case of a composite laminated conical shell, due to the manufacturing process, the thickness and the ply orientation are functions of the shell coordinates, which ultimately results in coordinate dependence of the stiffness matrices (A,B,D). These effects influence both the buckling load and the weight of the structure and complicate the optimization problem considerably. High computational cost is involved in calculating the buckling load by means of a high-fidelity analysis, e.g. using the computer code STAGS-A. In order to simplify the optimization procedure, a low-fidelity model based on the assumption of constant material properties throughout the shell is adopted, and buckling loads are calculated by means of a low-fidelity analysis, e.g. using the computer code BOCS. This work proposes combining the high-fidelity analysis model (based on exact material properties) with the low-fidelity model (based on nominal material properties) by using correction response surfaces, which approximate the discrepancy between buckling loads determined from different fidelity analyses. The results indicate that the proposed multi-fidelity approaches using correction response surfaces can be used to improve the computational efficiency of structural optimization problems.     

Tagged Systems: A Framework for the Specification of History-dependent Properties

We propose a general method for the treatment of history-dependent runtime errors. When one has to control this kind of errors, a tagged version of the language is usually defined, in which tags capture only the necessary information of the history of processes. We will characterize such tagged languages as being quotients of the reachability tree defined by the computations of the original language. From this fact we can conclude that the property characterized by each tagged language is indeed a property of the original one. In this way, we can work in a common framework, instead of defining an ad hoc semantics for each property. In particular, we could still use the analysis machinery existing in the calculus in order to prove that or other related properties. We have applied this methodology to the study of resource access control in a distributed π-calculus, called Dπ. In particular, we have proved that the tagged version of Dπ is indeed a tagging according to our definition.