• Journal of the Microelectronics and Packaging Society
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• v.18 no.2
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• pp.35-41
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• 2011

Recently, board level solder joint reliability performance of IC packages during drop impact becomes a great concern to semiconductor and electronic product manufacturers. The handheld electronic products are prone to being dropped during their useful service life because of their size and weight. The IC packages are susceptible to solder joint failures, induced by a combination of printed circuit board (PCB) bending and mechanical shock during impact. The board level drop testing is an effective method to characterize the solder joint reliability performance of miniature handheld products. In this paper, applying the JEDEC (JESD22-B111) standard present a finite element modeling of the FBGA. The simulation results revealed that maximum stress was located at the outermost solder ball in the PCB or IC package side, which consisted well with the location of crack initiation observed in the failure analysis after drop reliability tests.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1174-1177
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• 2006

A bottom contact organic thin film transistor (OTFT) is fabricated with an organic double-layered gate insulator (GI) and pentacene. The PMMA and MNB layers are treated on gate insulator and source/drain (S/D, Au) before depositing pentacene to investigate device properties and pentacene growth. The sequence of surface treatment affects a device performance seriously. The ultra-thin PMMA (below 50A) was deposited on organic gate insulator and S/D metal by spin coating method, which showed no deterioration of on-state current (Ion) although bottom contact structure was exploited. We proposed that the reason of no contact resistance (Rc) increase may be due to a wettability difference in between PMMA / Au and PMMA / organic GI. As a result, the device treated by $PMMA\;{\rightarrow}\;MNB$ showed much better Ion behavior than those fabricated by $MNB\;{\rightarrow}\;PMMA$. We will report the important physical and electrical performance difference associated with surface treatment sequence.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.1
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• pp.57-62
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• 2009

Recently, with the increasing lightness and miniaturization of high resolution camera phones, the demand for aspheric glass lens has increased because plastic and spherical lens are unable to satisfy the required performance. An aspheric glass lens is fabricated by the high temperature and pressure molding using a tungsten carbide molding core, so precision grinding technology for the molding core surface are required. This paper reports a development of feedrate control grinding method for aspherical molding core using parallel grinding method. A plane molding core was ground using conventional and feedrate control grinding method. The performance of the feedrate control method was evaluated by measurement of surface roughness. The result indicated that the average surface roughness was reduced to 1.5 nm, which is more efficient than the conventional grinding method.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.395-401
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• 2008

Since metallic foam will increase the performance of heat exchanger, it have caused many researcher's attention recently. Our research base on the model that metallic foams applied to heat exchanger. In this case, there is three kind of heat transfer mechanisms, heat conduction in fibers, heat transfer by conduction in fluid phase, and internal heat change between solid and fluid phases. In this paper we study both the hydraulic and thermal aspect performance. Pressure drop along air flow direction will be presented. As thermal aspect, we first discuss the acceptance of applying thermal equilibrium among the two phases. then to calculate the dimensionless temperature profile, the heat transfer coefficient and Nu number in 14 metallic foams(7 Aluminium foams, 7 FeCrAlY foams). All these discussion is based on the same velocity u=2 m/s.

• Korean small business review
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• v.42 no.1
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• pp.107-133
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• 2020

Many researchers conducted studies on the relationship between entrepreneur's characteristic, capability, strategy and performance of new venture. However, the development of scientific technique and the complexity of the business environment have stimulated entrepreneurial teams rather than individuals. Therefore, the necessity of theoretical and practical study on the effect of the characteristics of an entrepreneurial team on the new venture companies was suggested. Initial research on entrepreneurial team diversity has primarily addressed the impact of demographic diversity on performance. In order to verify the research model of this study, 287 delegates of new venture companies that participated in the projects at the 18 Centers for Creative Economy & Innovation in 17 regions of the country conducted validity and reliability test based on the questionnaire to which they answered. The result shows that only gender diversity among demographic diversity affected non-financial performance. Information diversity influenced career diversity on financial performance and diversity in education on non-financial performance. Also, the higher the previous sharing experience, the better the financial performance. Value diversity has negative effect on both financial and non-financial performance. Based on the results, theoretical and practical implications are derived. Also suggested are methodological limitations and future research directions.

• Culinary science and hospitality research
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• v.22 no.8
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• pp.1-16
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• 2016

The purpose of this study is to verify the effects of team trust and cooperative behavior on the food-service employees' perceived service performance as well as the moderating effects of team competency and other department support in the relationship among the team trust, cooperative behavior, and service performance of food-service employees. We conducted a survey of 1,080 food-service employees working in 8 hotels and 4 food-service stores located in Seoul, Gyeonggi, Song-do, Gyeongju, and Busan, and 841 food-service employees were employed for statistical analysis except unreliable responses. As a result of a SEM (structural equation modeling) analysis to confirm hypotheses, it was found that team trust (leader trust and co-worker trust) had a positive effect on the cooperative behavior. In addition, the cooperative behavior had a positive influence on the food-service employees' perceived service performance. Also found was the moderating effect of other department support in the relationship between the cooperative behavior and food-service employees' perceived service performance. Based on the research findings, we discussed its academic and practical implications, and suggestions on the future research.

• Journal of Digital Convergence
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• v.17 no.10
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• pp.59-66
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• 2019

The purpose of this study was to investigate the effect of empowerment on organizational commitment and team performance after establishing their relationship through research on empowerment, organizational commitment, and team performance. The main results were as follows: First, empirical results showed that organizational commitment and team performance had a significant influence on the relationship between empowerment and organizational effectiveness. Second, the role of empowerment The results of this study suggest that empowerment has a positive effect on organizational commitment and team performance when the perceived fairness perception is high. In order for the company to continue to grow, the most important thing is that the cycle of continuous empowerment of its employees as a human resource is considered as an alternative to sustain the continuous growth of the organization. To this end, companies offer their future vision and goals that they can share I think we should continue to pursue changes in the organization. Based on the results of the study, the implications and limitations of the research and future direction of the research were suggested.

• The Korean Journal of Pesticide Science
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• v.16 no.3
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• pp.195-201
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• 2012

We tested for pesticide residues in 124 samples of 22 different items of imported fruits circulated in Gyeonggido. Total 218 pesticides were analyzed by multi-residue method using gas chromatography/nitrogen phosphorus detector-electron capture detector (GC/NPD-ECD), time of flight/mass spectrometer (TOF/MS), ultra performance liquid chromatography/photo diode array (UPLC/PDA), high performance liquid chromatography/fluorescence detector (HPLC/FLD) and mass spectrometer (LC/MS/MS). The pesticides were detected in 18 fruits samples, ranging 0.003~0.3 mg/kg and no samples had violative residue. The separation test to 14 sample pesticides detected was conducted to monitor the current status of pesticide residues according to the partial characteristic. The pesticides were detected in 14 peels ranging 0.03~1.5 mg/kg and 2 fleshes in less than detection limits. These results indicate that imported fruits are safe when the human takes normally but even the small amount of pesticides is harmful when the human takes it in a prolonged period. Therefore, the pesticide residual amounts of imported friuts should be constantly monitored for food safety.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.217.1-217.1
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• 2003

Phytoestrogen has been used as supplement in order to treat osteoporosis. The representative phytoestrogen, isoflavones, are daidzein, genistein and formononetin which were present highly in legumes. We have studied the quantitative analysis of isoflavones in KUNBO by HPLC. KUNBO, a mixed herbal extract including Astragali Radix and Rhynchosiae nulubilis Semen (Leguminosae), etc., is a nutraceutical candidate for type I osteoporosis. olumn used in HPLC was LUNA 5${\mu}$ C18 (250 ${\times}$4.6mm) (Phenmenex Co.m Torroance, CA, U.S.A.). (omitted)

• International conference on construction engineering and project management
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• 2009.05a
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• pp.338-344
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• 2009

Organizational learning of construction team has been long addressed in the literatures, but the mechanism of learning and the influence of leader in the team still remain vague. This paper presents a computational model (OLT) depicting the mechanism and the influence of leader in a systemic way. The OLT model is a multi-agent system based on some eloquent propositions proposed in previous researches. The proposed model is preliminarily validated by some toy-problem simulations. In the OLT model, the leader is assigned as a project manager. The results show that a proper leader can effectively improve the learning process and the result-in performance, in which the team learning is mainly affected by both the leader and the majority in a team. Based on our findings, two propositions are concluded accordingly: (1) Learning of a team would be enhanced if a proper leader is assigned; (2) The effectiveness of learning would increase in a team, in which the members retain explorative attitudes.