Application of a variable filter for presampled modulation transfer function analysis with the edge method

We devised a new noise filtering method to reduce the noise in the line spread function (LSF) for presampled modulation transfer function (MTF) analysis with the edge method. A filter was designed to reduce noise effectively using a position-dependent filter controlled by the boundary frequency b for low-pass filtering, which is calculated by 1/2d (d: distance from the LSF center). In this filtering process, strong filters with very low b can be applied to regions distant from the LSF center, and the region near the LSF center can be maintained simultaneously by a correspondingly high b. Presampled MTF accuracies derived by use of the proposed method and an edge spread function (ESF)-fitting method were compared by use of simulated ESFs with and without noise, resembling a computed radiography (CR) and an indirect-type flat panel detector (FPD), respectively. In addition, the edge images of clinical CR, indirect-type FPD, and direct-type FPD systems were examined. For a simulated ESF without noise, the calculated MTFs of the variable filtering method agreed precisely with the true MTFs. The excellent noise-reduction ability of the variable filter was demonstrated for all simulated noisy ESFs and those of three clinical systems. Although the ESF-fitting method provided excellent noise reduction only for the CR-like simulated ESF with noise, its noise elimination performance could not be demonstrated due to the lesser robustness of the fitting. © 2015, Japanese Society of Radiological Technology and Japan Society of Medical Physics.発行後1年より全文公

H2-reduction Behavior of FeS-CaO Mixture during Microwave Heating

[EN] Microwave irradiation is an energy-efficient and a rapid-heating method to decrease the activation energy of chemical reactions via both thermal and non-thermal effects of microwave photons 1). Recently, hydrogen-reduction during microwave heating has been proposed for magnetite reduction to combine the advantages of microwave irradiation and using H2 as a reducing agent during iron production 2). In the present study, as a novel idea, the traditional microwave heating system was equipped with thermobalance to investigate the kinetics of H2-reduction of FeS-CaO mixture (FeS(s) + CaO(s) + H2(g) = Fe(s) + CaS(s) + H2O(g)) under microwave heating at 2.45 GHz to further mitigate CO2 emission and prevent SO2 release during iron production from a sulfide mineral. Microscope observations revealed that the un-reacted core model can be employed for such a kinetic study. Linearity (R2) of different rate-controlling mechanisms after a 10-minute reduction reaction demonstrated that the gas diffusion in micropores of reduced metallic Fe is a dominant rate-controlling mechanism while the interfacial chemical reaction is progressed rapidly. This is attributed to extraordinary effects of microwave irradiation on speeding up the chemical reactions 3), while the formation of Fe shell on the surface of FeS/FeO particles decreases the accessibility of gas to un-reacted parts, resulting in a lower rate of gas diffusion in micropores. Moreover, the diffusion coefficients (De) at 460, 570, and 750 °C were calculated from the plot of the gas diffusion, as illustrated in Fig. 1, wherein the X is reduction degree: where Wi (g) is the initial weight of the sample, Wt (g) is the weight of the sample after treatment for t seconds, Wht (g) is the weight change of the sample owing to the dehydration reaction, and WO (-) is the stoichiometric weight ratio of oxygen in the sample, which is 0.111. Consequently, the activation energy of 22.3 kJ.mol-1 was attained from the Arrhenius equation for the hydrogen-reduction reaction of FeS-CaO mixture under microwave heating.Amini, A.; Ohno, K.; Maeda, T.; Kunitomo, K.; Kashimura, K. (2019). H2-reduction Behavior of FeS-CaO Mixture during Microwave Heating. En AMPERE 2019. 17th International Conference on Microwave and High Frequency Heating. Editorial Universitat Politècnica de València. 357-364. https://doi.org/10.4995/AMPERE2019.2019.9755OCS35736

ダイガクセイ ノ BigV セイカク トクセイ ト モクヒョウ シコウセイ ガ リシュウ カモク ノ シケン セイセキ ニ オヨボス コウカ ゲンイン キゾク ト カンジョウ オ カラメテ

本研究の目的は、大学生のパーソナリティ要因であるBig Vと認知的動機づけ要因である目標志向性が大学生の履修科目の試験成績に及ぼす効果を検討することである。まず最初に教育心理学専門用語の英語─日本語50 ペアを記したプリントを配布した。そして、1 週間後にその中から10 題を出題する試験を行うと伝えた。1 週間後、試験前に事前の勉強量を測る50 題全問のメモ課題を課した。その後、10 題からなるテストを実施し、その際に自作のメモを見ながら解答することを認めた。その1 週間後に2 つの答案を返却し、テストについては平均点と得点分布について講評し、その後原因帰属および感情を問う質問紙に回答させた。さらにその2 週間後、予告なしに全く同じ問題の抜打テストを実施した。分析の結果、目標達成志向性の遂行接近志向性はメモ得点およびテスト得点と有意な正の相関があること、Big Vの誠実性がメモ得点と有意な正の相関があること、調和性はメモ得点およびテスト得点と有意な正の相関があることがわかった。また、外向性と開放性はテスト得点とは有意な相関がみられなかった一方、抜打得点とは両者とも有意な正の相関がみられた。さらに、帰属と感情の関連についても論じられた。The purpose of this study was to examine the effect of students’ Big Five personality traits and goalorientation on memo score meaning preliminary effort, academic score and retest score. Thirty-nine undergraduate students in a psychology course participated in this study. The experimental procedure was as follows. 1） They were given a list which consisted of 50 English-Japanese pairs of technical terms on educational psychology, and explained that they would take a test consisting of 10 pairs from the list next week. 2） After one week, they took two types of tests: a memo test measuring the degree of their preliminary effort and the main test. 3） The following week, we returned both graded tests to them, and informed them the average score and the score distribution on the main test. They then answered a questionnaire regarding causal attribution and emotions. 4） Two weeks later, an unannounced test was imposed which consisted of the same problems as the main test. We analyzed the relations between 8 variables（Big Five, goal orientation）and 3 scores: memo score, main test score and retest score. Results showed that 1） performance approach orientation correlated with memo score and test score（r＝.44＊, r＝.38＊, respectively; ＊means p＜.05）, 2） conscientiousness correlated with memo score（r＝.40＊）, 3） agreeableness correlated with memo score and test score （r＝.48＊, r＝.44＊, respectively）, 4） extraversion and openness correlated with retest score（r＝.37＊, r＝.40＊, respectively）. Moreover, relationships of causal attribution and emotions were discussed