Aerodynamic Optimization Design System for Turbomachinery Based on Parallelized 3D Viscous Numerical Analysis

Zhirong LIN,Bo CHEN,Xin YUAN 한국전산유체공학회 2006 한국전산유체공학회 학술대회논문집 Vol.2006 No.5

Adsorption behavior of U(VI)/Th(IV) by acid-leached red mud: A comparative study

Liu Zhirong,Xiong Huanjia,Zhou Shaoqi 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.5

Acid-leached red mud, a type of inorganic-adsorptive by-product of bauxite Bayer process via acid leaching,was used for the removal of U(VI)/Th(IV) from aqueous solutions. Variables of the adsorption such as contact time,temperature, solution pH, initial concentration and dose of acid-leached red mud were investigated. The results indicated that the adsorption is strongly affected by dosage, the solution pH, contact time and initial concentration. The isothermal data were fitted with both Langmuir and Freundlich equations, but the data fitted the former better than the latter. A pseudo-first-order kinetic model and pseudo-second-order kinetic model were used to describe the kinetic data, but the pseudo-second-order kinetic model was the better. Thermodynamic parameters such as enthalpy (ΔHo), entropy (ΔSo) and free energy change (ΔGo) were calculated, and the negative ΔGo values of U(VI)/Th(IV) at different temperatures confirmed the adsorption processes were spontaneous.

조직지원인식이 업무성과 및 생활만족도에 미치는 영향

전지영(Zhirong Tian),우주연(Ju-Yeon Woo),호민(Min Hu),곽원준(Won-Jun Kwak) 대한경영학회 2018 大韓經營學會誌 Vol.31 No.10

중국 근로자의 시간적 압박감이 직무성과에 미치는 영향

전지영(Zhirong Tian),곽원준(Won Jun Kwak) 대한경영학회 2016 大韓經營學會誌 Vol.29 No.1

급격한 경제성장으로 중국 기업의 근로자는 과거에 경험하지 못한 높은 업무량과 성과에 대한 기대로 인하여 근로시간이 증가하고 연장근무도 잦아지면서 시간적 압박감을 경험하고 있다. 중국 기업에서 근로자가 시간적 압박감을 느끼는 현상이 점차 보편화되고 일반적이 되어 가고 있지만 이에 대한 연구는 부족한 실정이다. 이에 본 연구에서는 중국 현지 근로자들을 대상으로 시간적 압박감이 직무성과에 미치는 영향을 조사하였다. 이와 더불어 이러한 시간적 압박감의 영향을 미치는 두 가지 조직 맥락적 요소인 근로자가 자신의 직속상사와 가지는 꽌시의 정도와 근무 형태(정상근무, 연장근무)의 효과를 분석하였다. 우선, 정상근무자와 연장근무자 모두 시간적 압박감이 증가할수록 더 높은 직무성과로 이어질 것으로 예측하였다. 이러한 예측은 자원보존이론에 근거한 것으로써, 개인은 시간과 같은 자신의 자원을 투입한 후에 이로 인한 효용을 얻고자하는 동기가 유발되는데 이러한 동기를 시간적 압박감이 촉발할 것이라는 논리에 근거하였다. 시간이 많지 않다는 느낌을 받는 개인은 투자하는 시간에 대한 성과를 얻지 못할지도 모른다는 긴박감으로 더 노력하고 이러한 노력은 직무성과를 향상시킬 것이기 때문이다. 다음으로, 시간적 압박감과 직무성과의 관계가 상사-부하 꽌시가 높아지면서 약해질 것이고, 이러한 상사-부하 꽌시의 효과는 연장근무자보다 정상근무자에게 더 두드러질 것으로 예측하였다. 이러한 예측은 근로자가 상사와 꽌시를 가지면서 여러 가지 업무적 및 비업무적 도움(예. 데드라인 연장, 마감을 지키지 않는데 대한 페널티의 제거)을 받게 되면서 시간적 압박감이 굳이 없더라도 높은 직무성과를 내게되면서, 시간적 압박감으로 인해 직무성과가 상승하는 정도가 감소하기 때문이다. 이러한 꽌시의 효과는 정상근무자에게 특히 두드러지고 연장근무자에게는 크게 나타나지 않을 것인데, 그 이유는 연장근무자는 상사의 꽌시로 인해 주어질 수 있는 혜택인 데드라인의 연장이나 늦은 마감의 허용 등을 연장근무로 인하여 꽌시없이도 얻을 수 있을 것이기 때문이다. 즉, 연장근무자보다 정상근무자에게 상사-부하 꽌시가 시간적 압박감과 직무성과의 관계에서 더 중요한 역할을 할 것으로 예상하는 것이다. 이상의 연구 가설을 실증하기 위하여 중국에서 근무하고 있는 정상근무자와 연장근무자 총 170명을 대상으로 설문조사를 실시하였다. 요인분석과 상관분석을 통하여 설문으로 얻은 자료의 가용성을 확인한 후에 수행한 다중회귀분석 결과는 다음과 같았다. 시간적 압박감이 높을 때 직무성과가 높을 것이라는 가설은 정상근무자와 연장근무자에게 모두 지지되었다. 또한, 정상근무자의 경우, 시간적 압박감과 직무성과의 관계는 상사-부하 꽌시가 높아질수록 약화된 것으로 나타났다. 반면, 연장근무자의 경우, 시간적 압박감과 직무성과의 관계는 상사-부하 꽌시의 유의미한 영향을 받지 않는 것으로 나타났다. 연구결과를 종합하면, 시간적 압박감을 느끼는 중국 근로자들은 더 높은 성과를 올리는데, 이러한 시간적 압박감의 긍정적 효과는 근로자가 정상 근무를 하면서 상사-부하 꽌시가 높은 경우에 다소 약화된다는 것이다. 본 연구의 결과는 시간적 압박감이 직무성과를 향상시키는 경향을 보이는 직장에서 고려해야 할 사항들에 대하여 함의를 제공하고 있다. 사회주의와 이로 인한 국가 및 조직문화에 익숙한 중국근로자들에게도 시간적 압박감을 경험하게 하는 것은 직무성과 향상에 긍정적인 영향을 주지만, 이러한 긍정적인 영향은 꽌시에 의해 약해지고 이러한 꽌시의 부정적인 영향은 근무시간을 준수하는 경우에 더욱 심해질 수 있다는 점을 중국 기업과 중국에서 운영 중인 외국기업들의 인사관리와 조직운영에 참고해야 할 것이다. Given the fast economic growth in China, Chinese employees have experienced increased workload and have suffered from high time pressure. Although this time pressure has become common in Chinese workplaces, little is known on how it would influence Chinese employees. Acknowledging this, the present study investigated the effects of time pressure on the task performance among Chinese employees in a large IT company located in the mainland China. It was also examined how these effects would be moderated by supervisor-subordinate Guanxi and how this moderation would be varied between “normal employees” (employees who work for normal business hour) and “overtime employees” (employees who work overtime). 〈Figure 1〉 shows the research conceptual model. [그림본문참조] We expected that the more time pressure was to both normal and overtime Chinese employees, the higher their task performance would be. This prediction was made based on conservation of resources theory. Conservation of resources theory posits that individuals would highly motivated to acquire any positive outcomes from their input. Accordingly, Chinese employees who feel little time left for completing their work might be concern about failure in obtaining outcomes within deadline, and this time pressure might improve those employees’ task performance by motivating them to work more and longer. We also expected that the stronger supervisor-subordinate Guanxi was, the weaker the relationship between time pressure and task performance would be, especially for normal employees compared to overtime employees. As Chinese employees develops good Guanxi relationships with their supervisors, the supervisors might provide several tangible and intangible benefits to the employees, which would help them perform their task better on the job. With the improved task performance level, Chinese employees might have the reduced room in task performance that time pressure could positively influence and enhance, which suggests that the effects of Chinese employees’ time pressure on their task performance would decrease. Importantly, this decrease in time pressure impact might be more salient for normal employees compared to overtime ones. Chinese employees who worked overtime might need less some tangible and intangible benefits (an extended deadline and no penaltity for late submission) provided from good Guanxi relationships, because those benefits were not so meaningful to them. Therefore, a supervisor-subordinate Guanxi relationship might have less influence on overtime employees, compared to normal ones who could feel more necessity and appreciation for their “Guanxi” benefits, which suggests a weaker moderating effects of Guanxi on the time pressure-performance relationship for overtime, rather than normal, employees. Hypothesis 1: There would be a positive relationship between (a) normal and (b) overtime Chinese employees’ felt time pressure and task performance. Hypothesis 2: For normal, rather than overtime, Chinese employees, the positive relationship between felt time pressure and task performance would be weaker when their supervisor-subordinate Guanxi relationships are better. To empirically test our hypotheses, an online survey was conducted through the participating company’s intranet for 170 normal and overtime employees who were randomly selected from the whole white-collar employees in the IT company. The empirical results showed that, when both the normal and overtime employees had more time pressure, their task performance was higher. In addition, when their supervisor-subordinate Guanxi was higher, the positive effects of time pressure on task performance was reduced only for normal employees, not for overtime employees. Our study results suggested that, although time pressure was beneficial to improve Chinese employees’ task performance, it might not be so effective when those employees had good Guanxi relationships with their supervisors. Th

동료의 지식공유가 종업원 업무품질에 미치는 영향

전지영(Zhirong Tian),곽원준(Wonjoon Kwak) 대한경영학회 2016 대한경영학회 학술발표대회 발표논문집 Vol.2016 No.2

본 연구는 동료의 지식공유가 업무품질에 미치는 영향 과정에서 임파워링 리더십의 상호작용 효과를 살펴보고, 이러한 상호작용 효과가 자기효능감을 통하여 매개되는지 여부를 검증하고자 하였다. 자료 수집을 위해 현재 중국에서 근무하고 있는 종업원 128명의 개인을 대상으로 설문조사를 실시하였으며, 그중 96명의 자료가 분석에 사용되었다. 분석결과에서 보면, 먼저, 리더 임파워링 리더십이 높은 집단에서는 동료의 지식공유가 종업원 업무품질에 더 약한 영향을 끼치는 것으로 나타났고, 반면 리더 임파워링 리더십이 낮은 집단에서는 동료의 지식공유가 종업원 업무품질에 더 강한 영향이 나타났다. 둘째, 자기효능감이 높은 집단에서는 동료의 지식공유가 종업원 업무품질에 더 약한 영향을 끼치는 것으로 나타났고, 자기효능감이 낮은 집단에서는 동료의 지식공유가 종업원 업무품질에 더 강한 영향을 끼치는 것으로 나타났다. 마지막으로, 종업원 업무품질에 미치는 동료의 지식공유와 리더 임파워링 리더십의 상호작용 효과는 자기효능감을 통하여 매개되는 것으로 나타났으며, 이러한 상호작용 효과는 Edwards와 Lambert(2007)의 권고상황에 따라 동료의 지식공유와 임파워먼트 리더십의 상호작용 효과가 자기효능감에 대한 영향을 검증하였다. 이러한 결과를 바탕으로 종업원 업무품질에 미치는 동료의 지식공유, 리더의 임파워링 리더십, 자기효능감의 상호 영향 관계에 대해 논의하고 향후 연구를 위한 제언을 제시하였다. The purpose of this study is to examine the interaction effects of empowering leadership on the process that coworker knowledge sharing affects performance and the meditated moderation of interaction effects through self-efficacy. To empirically test our hypotheses, an survey was conducted through the participating company’s for 96(128 employees were surveyed, of which 96 responses were analyzed) employees who were randomly selected from the whole white-collar employees in the construction company. Results indicated that coworker knowledge sharing had greater effects on performance for people who were lower in empowering leadership and self-efficacy. Findings also showed that these moderating effects were mediated by self-efficacy. From these results, we discussed the interrelationship among these three variables on Performance and provided suggestions for furure study.

Optimizing the Novel Formulation of Liposome-Polycation-DNA Complexes (LPD) by Central Composite Design

Xun Sun,Zhirong Zhang 대한약학회 2004 Archives of Pharmacal Research Vol.27 No.7

LPD vectors are non-viral vehicles for gene delivery comprised of polycation-condensed plasmid DNA and liposomes. Here, we described a novel anionic LPD formulation containing protamine- DNA complexes and pH sensitive liposomes composed of DOPE and cholesteryl hemisuccinate (Chems). Central composite design (CCD) was employed to optimize stable LPD formulation with small particle size. A three factor, five-level CCD design was used for the optimization procedure, with the weight ratio of protamine/DNA (X1), the weight ratio of Chems/ DNA (X2) and the molar ratio of Chems/DOPE in the anionic liposomes (X3) as the independent variables. LPD size (Y1) and LPD protection efficiency against nuclease (Y2) were response variables. Zeta potential determination was utilized to define the experimental design region. Based on experimental design, responses for the 15 formulations were obtained. Mathematical equations and response surface plots were used to relate the dependent and independent variables. The mathematical model predicted optimized X1-X3 levels that achieve the desired particle size and the protection efficiency against nuclease. According to these levels, an optimized LPD formulation was prepared, resulting in a particle size of 185.3 nm and protection efficiency of 80.22%.

Mathematical programming model of process plant safety layout using the equipment vulnerability index

Liping Guo,Zhirong Wang,Pinkun Guo,Jinghong Wang,Dan Zhao 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.4

Safety is the focus of attention in plant layout problems. Previous studies have often expressed safety as a cost of risk, that is, the cost of property losses that may occur in an accident. In this paper, the influence of uncertainty on the equipment vulnerability is quantitatively considered and a more reliable process plant layout is proposed. The equipment vulnerability index is used to evaluate the vulnerability level of the target equipment in case of an accident, which is applied to propose a mixed-integer nonlinear optimized process plant layout to minimize domino risk. In addition, a decision matrix is applied to determine whether the risk level of the optimized layout of the target equipment is acceptable. Damage probability and vulnerability are the basic inputs of this matrix. The proposed method was applied to a coal-water slurry gasification process and the results show that the layout obtained by the proposed model has better practical value than the current layout, reducing the domino risk by 53.2%. Meanwhile, the model can be used to identify critical equipment and select targeted safety measures during the production stage.

A Case of Familial Cold Autoinflammatory Syndrome with De Novo NLRP3 Mutation

( Wenqing Zhang ),( Zhirong Yao ) 대한피부과학회 2021 Annals of Dermatology Vol.33 No.2

Comparative study of small crack growth behavior between specimens with and without machining-induced residual stress of alloy GH4169

Lei Zhu,Zhirong Wu,Xuteng Hu,Yingdong Song 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.11

We investigated the small fatigue crack behavior of alloy GH4169 by using single-edge-notch tension specimens. Residual stress introduced by machining process was taken into consideration, and two stress levels were selected. A comparison was made between the experimental results of specimens with and without machining-induced residual stress. The results indicated that fatigue cracks of the two types of specimens initiated from surface inclusions or grain boundaries. For both types of specimens, small cracks grew very slowly when the crack lengths were less than 500 μm. The small crack growth might decelerate and retard temporarily for the existence of grain boundaries. The residual stress effect on crack growth can be identified at σ max = 380 MPa, i.e., compressive residual stress might impede the crack growth. However, this phenomenon was indistinguishable at σ max = 410 MPa.

Quality Comparison of Sweet Flour Pastes Produced via Natural and Temperature-controlled Fermentation

Jing Deng,Huachang Wu,Zhirong Yang 한국식품과학회 2015 Food Science and Biotechnology Vol.24 No.6

The quality of sweet flour pastes (SFP) produced via natural and temperature-controlled fermentation was investigated. Temperature-controlled fermentation shortened the production time with no significant (p<0.05) differences between sample types in amino nitrogen, total acid, reducing sugar, and organic acid concentrations observed at the end of fermentation. Naturally fermented SFP exhibited higher concentrations of free amino acids than temperature-controlled fermented SFP. Analysis of SFP volatile compounds showed that naturally fermented SFP samples had higher concentrations of aroma constituents. Ethyl palmitate was the dominant ester in SFP with a 5.2× higher content of ethyl palmitate than for naturally fermented SFP. In addition, 4-ethyl guaiacol and 4-vinyl guaiacol were only identified in naturally fermented SFP samples. Temperature-controlled fermentation accelerates the production process, and naturally fermented SFP exhibited a higher quality.