중금속 이온과 질소-황을 포함하는 포단드와의 착물형성에 관한 연구

정징운,이선하,최규성,강동현 慶南大學校 附設 基礎科學硏究所 1997 硏究論文集 Vol.10 No.-

The stability constant, enthalpy, and etropy changes of complexation of heavy metal ions (Zn²*, Cd²*) with podands containing nitrogen-sulfur donors such as tri(phenylthio-2-ethyl)amine (Podand Ⅰ), tri(benzylmercapto-2-ethyl)amine(Podand Ⅱ), and tetra(phenylthio-2-ethyl)ethylenediamine (Podand Ⅲ) have been determined by using potentiometric titration in 95% MeOH at various temperature. We observed the Podand Ⅲ ligand showed the largest protonation constant. The values of protonation constant and stability constant for Zn(Ⅱ), and Cd(Ⅱ) ions among three different ligands were increased as following order, Podand Ⅰ< Podand Ⅱ< Podand Ⅲ. In addition, thermodynamic parameters ΔH and TΔS of Zn(Ⅱ), Cd(Ⅱ) complexes have studied.

한국인 직무 스트레스 측정도구의 개발 및 표준화

장세진,고상백,강동묵,김성아,강명근,이철갑,정진주,조정진,손미아,채창호,김정원,김정일,김형수,노상철,박재범,우종민,김수영,김정연,하미나,박정선,이경용,김형렬,공정옥,김인아,김정수,박준호,현숙정,손동국 大韓産業醫學會 2005 대한직업환경의학회지 Vol.17 No.4

Background and Purposes: Over the past three decades, numerous studies performed in Korea have reported that job stress is a determinant risk factor for chronic diseases and work disability. Every society has its own culture and occupational climate particular to their organizations, and hence experiences different occupational stress. An occupational stress measurement tool therefore needs to be developed to estimate it objectively. The purpose of this study is to develop and standardize the Korean Occupational Stress Scale (KOSS) which is considered to be unique and specific occupational stressors in Korean employees. Subjects and Methods: Data were obtained from the National Study for Development and Standardization of Occupational Stress (NSDSOS Project: 2002-2004). A total of 12,631 employees from a nationwide sample proportional to the Korean Standard Industrial Classification and the Korean Standard Occupational Classification were administered. The KOSS was developed for 2 years (2002-2004). In the first year, we collected 255 items from the most popular job stress measurement tools such as JCQ, ERI, NIOSH and OSI, and 44 items derived from the a qualitative study (depth interview). Forty-three items of KOSS, in the second year, were retained for use in the final version of the KOSS by using Delphi and factor analysis. Items were scored using conventional 1-2-3-4 Likert scores for the response categories. Results: We developed eight subscales by using factor analysis and validation process: physical environment (3 items), job demand (8 items), insufficient job control (5 items), interpersonal conflict (4 items), job insecurity (6 items), organizational system (7 items), lack of reward (6 items), and occupational climate (4 items). Together they explained 50.0% of total variance. Internal consistency alpha scores were ranged from 0.51 to 0.82. Twenty-four items of the short form of the KOSS (KOSS-SF) were also developed to estimate job stress in the work setting. Because the levels of the subscales of occupational stress were gender dependent, gender-specific standard norms for both the 43-item full version and the 24-item short form using a quartile for the subscales of KOSS were presented. Conclusion: The results of this study suggest that KOSS might be an appropriate measurement scale to estimate occupational stress of Korean employees. Further and more detailed study needs to be conducted to improve the validity of this scale.

Investigating the Link Among LMA, FLLA, and Listening Comprehension of Chinese EFL Learners

Jing Sun(Jing Sun),Dong-Jin Shin(Dong-Jin Shin) 한국영어학학회 2024 영어학연구 Vol.30 No.1

Enhancing metacognitive awareness is considered an accelerating factor in listening skill development and empowers listeners’ autonomy. Anxiety is believed to be one of the affective factors that hinder the listening process the most. Previous studies have revealed that listening metacognitive awareness (LMA) and foreign language listening anxiety (FLLA) are related to listening performance. Interestingly, the interaction among LMA, FLLA, and English listening proficiency (ELP) in the context of English Major university students in China is not paid much attention to. This study examines the relationship among university students’ LMA, FLLA, and ELP. Besides, the impact of LMA and FLLA on the high- and low-proficiency groups of English listening is discussed. To this end, 276 English Major senior students were recruited to attend the experiment. To address the research questions, quantitative data analysis techniques, including descriptive statistics analysis, Pearson correlation, and Binary logistic regression, were run to analyze the data. Results reveal a significant positive correlation between the participants’ LMA and ELP. A significant and negative correlation between their FLLA and ELP is observed. Finally, LMA and FLLA both function significantly in grouping participants’ ELP into high- and low levels.

Research on Temperature Points Selection of the Non-source Temperature Calibration Method Based on Pyrometer Transfer Function

Sun Kun,Wang Jing,Wang Hongchao,Yu Limei,Li Chenyang,Zhang Xiaowen 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.11

The non-source temperature calibration method of the multi-spectral pyrometer (MSP), put forward in the previous article, is the non-source calibration method based on the MSP transfer function (NCCTF). In this paper, the practicability of NCCTF is researched. The situations that maybe encountered of the temperature points in the actual calibration process are simulated. The impact of the intervals temperature points of different number and unequal intervals temperature points on the NCCTF accuracy are researched theoretically to determine the temperature points select method. Simulation experimental results show that the NCCTF can meet the actual calibration process with good usability.

Research on Competitive Swimming Sports based on Optimal Control Theory

Jing meng Sun,Yueqiu Han,Hui Li 보안공학연구지원센터 2014 International Journal of Multimedia and Ubiquitous Vol.9 No.9

Muscle fatigue: general understanding and treatment

Jing-jing Wan,Zhen Qin,Peng-yuan Wang,Yang Sun,Xia Liu 생화학분자생물학회 2017 Experimental and molecular medicine Vol.49 No.-

Muscle fatigue is a common complaint in clinical practice. In humans, muscle fatigue can be defined as exercise-induced decrease in the ability to produce force. Here, to provide a general understanding and describe potential therapies for muscle fatigue, we summarize studies on muscle fatigue, including topics such as the sequence of events observed during force production, in vivo fatigue-site evaluation techniques, diagnostic markers and non-specific but effective treatments.

A model for the electrical characteristics of metal-ferroelectric-insulator-semiconductor field-effect transistor

Jing Sun,Xue Jun Zheng,Wen Li 한국물리학회 2012 Current Applied Physics Vol.12 No.3

An improved theoretical model on the electrical characteristics of metal-ferroelectric-insulatorsemiconductor field-effect transistor (MFIS-FET) has been proposed by considering the historydependent electric field effect and the mobility model. The capacitanceevoltage (CeV) characteristics of MFIS structure is evaluated by combining the switching physics of ferroelectric with the silicon physics, and the drain current-gate voltage (ID-VGS) and drain current-drain voltage (ID-VDS) characteristics of MFIS-FET are modeled by combining the switching physics of ferroelectric with Pao and Sah’s double integral. For two MFIS-FETs with SrBi2Ta2O9 and (Bi,La)4Ti3O12 ferroelectric layers, the CeV, ID-VGS and ID-VDS characteristics are simulated by using the improved model, and the results are more consistent with the previous experiment than those based on Lue model, indicating that the improved model is suitable for simulating the electrical characteristics of MFIS-FET. This work is expected to provide some guidance to the design and performance improvement of MFIS structure devices.

Contact forces generated by fallen debris

Sun, Jing,Lam, Nelson,Zhang, Lihai,Gad, Emad,Ruan, Dong Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.50 No.5

Expressions for determining the value of the impact force as reported in the literature and incorporated into code provisions are essentially quasi-static forces for emulating deflection. Quasi-static forces are not to be confused with contact force which is generated in the vicinity of the point of contact between the impactor and target, and contact force is responsible for damage featuring perforation and denting. The distinction between the two types of forces in the context of impact actions is not widely understood and few guidelines have been developed for their estimation. The value of the contact force can be many times higher than that of the quasi-static force and lasts for a matter of a few milli-seconds whereas the deflection of the target can evolve over a much longer time span. The stiffer the impactor the shorter the period of time to deliver the impulsive action onto the target and consequently the higher the peak value of the contact force. This phenomenon is not taken into account by any contemporary codified method of modelling impact actions which are mostly based on the considerations of momentum and energy principles. Computer software such as LS-DYNA has the capability of predicting contact force but the dynamic stiffness parameters of the impactor material which is required for input into the program has not been documented for debris materials. The alternative, direct, approach for an accurate evaluation of the damage potential of an impact scenario is by physical experimentation. However, it can be difficult to extrapolate observations from laboratory testings to behaviour in real scenarios when the underlying principles have not been established. Contact force is also difficult to measure. Thus, the amount of useful information that can be retrieved from isolated impact experiments to guide design and to quantify risk is very limited. In this paper, practical methods for estimating the amount of contact force that can be generated by the impact of a fallen debris object are introduced along with the governing principles. An experimental-calibration procedure forming part of the assessment procedure has also been verified.

Contact forces generated by fallen debris

Jing Sun,Nelson Lam,Lihai Zhang,Emad Gad,Dong Ruan 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.50 No.5

Expressions for determining the value of the impact force as reported in the literature and incorporated into code provisions are essentially quasi-static forces for emulating deflection. Quasi-static forces are not to be confused with contact force which is generated in the vicinity of the point of contact between the impactor and target, and contact force is responsible for damage featuring perforation and denting. The distinction between the two types of forces in the context of impact actions is not widely understood and few guidelines have been developed for their estimation. The value of the contact force can be many times higher than that of the quasi-static force and lasts for a matter of a few milli-seconds whereas the deflection of the target can evolve over a much longer time span. The stiffer the impactor the shorter the period of time to deliver the impulsive action onto the target and consequently the higher the peak value of the contact force. This phenomenon is not taken into account by any contemporary codified method of modelling impact actions which are mostly based on the considerations of momentum and energy principles. Computer software such as LS-DYNA has the capability of predicting contact force but the dynamic stiffness parameters of the impactor material which is required for input into the program has not been documented for debris materials. The alternative, direct, approach for an accurate evaluation of the damagepotential of an impact scenario is by physical experimentation. However, it can be difficult to extrapolate observations from laboratory testings to behaviour in real scenarios when the underlying principles have not been established. Contact force is also difficult to measure. Thus, the amount of useful information that can be retrieved from isolated impact experiments to guide design and to quantify risk is very limited. In this paper, practical methods for estimating the amount of contact force that can be generated by the impact of a fallen debris object are introduced along with the governing principles. An experimental-calibration procedure forming part of the assessment procedure has also been verified.

Fast terminal sliding mode tracking control of hypersonic vehicles based on non-homogeneous disturbance observer

Jing-Guang Sun,Shen-Min Song,Hai-Tao Chen,Guan-Qun Wu 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.6

The tracking control problem of hypersonic vehicles is studied and analyzed in this paper using terminalsliding mode control method (TSMC) and non-homogeneous disturbance observer(NHDO) considering parametricuncertainty and external disturbances. Non-singular terminal sliding mode controller is provided based on NHDO. The key idea is that the NHDO is adopted to estimate the aerodynamic uncertainties and external disturbancessimultaneously, which can enhance the robustness of the system and lower the gain of the switch controller. Rigorousstability analysis for the closed-loop system is given via Lyapunov stability theory, which proves that thesystem states are always bounded even during the estimation process when the estimation error is not zero. Thesliding manifold can be reached in finite time and the tracking errors can converge to zero asymptotically. Numericalsimulations are conducted with the longitudinal nonlinear dynamic model of hypersonic vehicles to verify theeffectiveness and robustness of the designed controller.