WATER-COOLING CRUCIBLE VACUUM INDUCTION MELTING OF γ-TiAl BASED ALLOYS

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Research and Applications of Semi-solid Processing

Since it was pioneered by Flemings and otherresearchers [11, the semi-solid metal processingtechnique has been widely stUdied in the world.Especially in the past decade, SSM as a newproduct forming technique has been rapidly developed and put into commercial applications[2, 31. In recent years, with the development ofthe ado-industry of China, a lot of researchwork on SSM has been done, including the preparation of slumes, reheating and thixoforming[Al6]; moreover, great achievements have …     

Radioecological studies in Korea atomic energy research institute, KAERI

Regarding the assessment of the terrestrial food chain dose to man, radioecology may be the field that is focused on the transfer of radionuclides from environmental media to food crops. In Korea, the environmental transfer of radionuclides to staple food crops have been investigated at Korea Atomic Energy Research Institute (KAERI) for the last 25 y mainly through radiotracer experiments in greenhouses. As a result, several hundreds of parameter values for the prediction of the radionuclide transfer have been produced. Many of them appear in two recent publications of International Atomic Energy Agency. This paper outlines the KAERI's past radioecological work and introduces the ongoing research and future plans.     

Fault detection using dynamic time warping (DTW) algorithm and discriminant analysis for swine wastewater treatment

This paper proposes a diagnosis system using dynamic time warping (DTW) and discriminant analysis with oxidation-reduction potential (ORP) and dissolved oxygen (DO) values for swine wastewater treatment. A full-scale sequencing batch reactor (SBR), which has an effective volume of 20 m(3), was auto-controlled, and the reaction phase was performed by a sub-cycle operation consisting of a repeated short cycle of the anoxic-aerobic step. Using ORP and DO profiles, SBR status was divided into four categories of normal and abnormal cases; these were influent disturbance, aeration controller fault, instrument trouble and inadequate raw wastewater feeding. Through the DTW process, difference values (D) were determined and classified into seven cases. In spite of the misclassification of high loading rates, the ORP profile provided good diagnosis results. However, the DO profiles detected five misclassifications that indicated different statuses. After the DTW process, several statistical values, including maximum value, minimum value, average value, standard deviation value and three quartile values, were extracted and applied to establish the discriminant function. The discriminant analysis allows one to classify seven cases with a percentage of 100% and 92.7% for ORP and DO profiles, respectively. Consequently, the study showed that ORP profiles are more efficient than DO profiles as diagnosis parameters and DTW diagnosis algorithms and discriminants.     

Electrical characterization of n/p-type nickel silicide/silicon junctions by Sb segregation

In this paper, n/p-type nickel-silicided Schottky diodes were fabricated by incorporating antimony atoms near the nickel silicide/Si junction interface and the electrical characteristics were studied through measurements and simulations. The effective Schottky barrier height (SBH) for electron, extracted from the thermionic emission model, drastically decreased from 0.68 to less than 0.1 eV while that for hole slightly increased from 0.43 to 0.53 eV. In order to identify the current conduction mechanisms, the experimental current-temperature-voltage characteristics for the n-type diode were fitted based on various models for transport of charge carrier in Schottky diodes. As the result, the large change in effective SBH for electron is ascribed to trap-assisted tunneling rather than barrier height inhomogeneity.     

Real-Time Detection of Sub-ppm Aromatic Compounds in Alcohol by Surface Plasmon Resonance Using Label-Free Graphene

<正>The increasing importance of high-purity isopropyl alcohol(IPA) in semiconductor processing technology has led to a higher demand for technologies capable of detecting impurities in I PA.Although accurate and various impurity detection technologies have been developed,most of them have limitations in real-time and repeatable detection of impurities.Herein,for the first time,surface plasmon resonance(SPR) sensor was developed utilizing graphene transferred Au film(Au/graphene) to detect sub-ppm levels of 2,4-dinitrophenol(2,4-DNP) dissolved in IPA and this sensor demonstrates the ability to detect 2,4-DNP in real-time with great reversibility.     

Stress Corrosion Behavior of MIG Welded Joints of 6082-T6 Aluminum Alloy at Different Temperatures

6082-T6 aluminum alloy is a commonly used aluminum alloy material in the field of rail transit because of its good molding properties, high mechanical properties, excellent corrosion resistance and weldability. In the high temperature and humid environment, the temperature change is bound to affect the stress corrosion resistance of the aluminum alloy and their welded joint. However, the influence mechanism of temperature on its stress corrosion resistance has not been explained in the existing research. In this paper, the mechanical properties and stress corrosion behaviors of melt-inert gas welded（MIG） 6082-T6 aluminum alloy welded joints were systematically studied under various temperatures condition. Results indicated the temperature scarcely affected stress corrosion cracking susceptibility index(P_SCC) of base metal, while significantly affected the welded joint and higher temperature caused lower P_SCC. After slow strain rate tensile test, a corrosion layer was formed, which was a typical brittle-toughness mixed failure, and the degree of brittleness increased with the increasing of temperature. Electrochemical analysis showed that corrosion resistance of the joint slightly decreased due to aluminum alloy accelerated dissolution caused by increasing of temperature. The proposed research will provide a theoretical basis for solving aluminum alloys used in rail transit, ship accessories and other industrial fields.     

Functionalized metal–organic frameworks with strong acidity and hydrophobicity as an efficient catalyst for the production of 5-hydroxymethylfurfural

In the dehydration of fructose to 5-hydroxymethyl furfural(HMF), in situ produced water weakens the acid strength of the catalyst and causes the rehydration of HMF, causing unsatisfactory catalytic activity and selectivity. In this work, a class of benzenesulfonic acid-grafted metal–organic frameworks with strong acidity and hydrophobicity is obtained by the direct sulfonation method using 4-chlorobenzenesulfonic acid as sulfonating agent. The resultant MOFs have a specific surface area of greater than 250 m~2·g~(-1), acid density above 1.0 mmol·g~(-1), and water contact angle up to 129°. The hydrophobic MOF-Ph SO_3 H exhibits both higher catalytic activity and selectivity than MOF-SO_3 H in the HMF synthesis due to its better hydrophobicity and olephilicity. Moreover, the catalyst has a high recycled stability. At last, fructose is completely converted, and 98.0% yield of HMF is obtained under 120 °C in a DMSO solvent system. The successful preparation of the hydrophobic acidic MOF provides a novel hydrophobic catalyst for the synthesis of HMF.