The two-way quality theory has been widely used as a method for classifying quality attributes for several decades. In particular, the Kano model that classifies attributes into not just conventional one-dimensional but must-be and attractive has gained popularity due to its applicability and ease of use. However, the wordings of the five alternatives in the Kano's questionnaire has been criticised for unclear meanings. This study proposes a new two-way model to classify attributes using 5-point Likert scale alternatives. For this, the current paper investigated a case of TV sets to examine how the proposed model works in comparison with the Kano model. The application results of the proposed model are different from the original one. The two-way model classifies quality attributes in more detail such as the “one-dimensional with an attractive tendency” attribute, which has a greater influence on satisfaction than dissatisfaction, the opposite “one-dimensional with a must-be tendency” attribute, and “highly one-dimensional” and “less one-dimensional” attributes. In this study, a potential satisfaction coefficient (PSC), a potential dissatisfaction coefficient (PDC), and an average potential coefficient (APC) to manage quality attributes are proposed and discussed for their utilization.

This study investigated the microstructure and wear resistance property of HPHT (high pressure high temperature) sintered PDC (polycrystalline diamond compact) in accordance with initial molding pressure. After quantifying an identical amount of diamond powder, the powder was inserted in top of WC-Co sintered material, and molded under four different pressure conditions (50, 100, 150, 200 kgf/cm2). The obtained diamond compact underwent sintering in high pressure, high temperature conditions. In the case of the 50 kgf/cm2 initial molding pressure condition, cracks were formed on the surface of PDC. On the other hand, PDCs obtained from 100~200 kgf/cm2 initial molding pressure conditions showed a meticulous structure. As molding pressure increased, low Co composition within PDC was detected. A wear resistance test was performed on the PDC, and the 200 kgf/cm2 condition PDC showed the highest wear resistance property.

This study investigates the microstructure and thermal shock properties of polycrystalline diamond compact (PDC) produced by the high-temperature, high-pressure (HPHT) process. The diamond used for the investigation features a 12~22 μm- and 8~16 μm-sized main particles, and 1~2 μm-sized filler particles. The filler particle ratio is adjusted up to 5~31% to produce a mixed particle, and then the tap density is measured. The measurement finds that as the filler particle ratio increases, the tap density value continuously increases, but at 23% or greater, it reduces by a small margin. The mixed particle described above undergoes an HPHT sintering process. Observation of PDC microstructures reveals that the filler particle ratio with high tap density value increases direct bonding among diamond particles, Co distribution becomes even, and the Co and W fraction also decreases. The produced PDC undergoes thermal shock tests with two temperature conditions of 820 and 830, and the results reveals that PDC with smaller filler particle ratio and low tap density value easily produces cracks, while PDC with high tap density value that contributes in increased direct bonding along with the higher diamond content results in improved thermal shock properties.

L-trans-pyrrolidine-2,4-dicarboxylate (PDC) is a potent inhibitor of glutamate transporters. In our current study, we investigated whether the neuronal death induced by PDC involves mechanisms other than excitotoxicity in mixed mouse cortical cultures. Cortical cultures at 13-14 days in vitro were used and cell death was assessed by measuring the lactate dehydrogenase efflux into bathing media. Glutamate and PDC both induced neuronal death in a concentration-dependent manner but the neurotoxic effects of glutamate were found to be more potent than those of PDC. Treatment with 10, 100 and 200 M PDC equally potentiated 50 M glutamate-induced neuronal death. The neuronal death induced by 75 M glutamate was almost abolished by treatment with the NMDA antagonists, MK-801 and AP-5, but was unaffected by NBQX (an AMPA antagonist), trolox (antioxidant), BDNF or ZVAD-FMK (a pan-caspase inhibitor). However, the neuronal death induced by 200 M PDC was partially but significantly attenuated by single treatments with MK-801, AP-5, trolox, BDNF or ZVAD-FMK but not NBQX. Combined treatments with MK-801 plus trolox, MK-801 plus ZVAD-FMK or MK-801 plus BDNF almost abolished neuronal death, whereas combined treatments with trolox plus ZVADFMK, trolox plus BDNF or ZVAD-FMK plus BDNF did not enhance the inhibitory action of any single treatment with these drugs. These results demonstrate that the neuronal death induced by PDC involves not only in the excitotoxicity induced by the accumulation of glutamate but also the oxidative stress induced by free radical generation. This suggests that apoptotic neuronal death plays a role in PDCinduced oxidative neuronal injury.

VOCs의 배출원은 자연적 배출원과 인위적인 배출원으로 나뉘는데, 주로 페인트 공정이나 자동차에서 인위적으로 다량 발생하여 신경계 교란물질이나 발암성으로 인체에 직접적인 피해를 주고 있어 VOC 저감에 대한 다양한 연구가 진행되고 있다. 플라즈마 기술은 높은 에너지에 의해 플라즈마가 형성되고, 이로 인해 자유전자가 생성되어 다양한 라디컬을 생성되어 유해성분들을 분해 저감시키고 화학적 반응을 가속화 시키는 원리를 이용하여 VOC 물질을 저감시킨다. 최근에는 제거 효율을 향상시키기 위해 플라즈마, 전자빔, 광촉매 등 여러 기술을 융복합하여 각 기술의 단점을 보완하여 이용되기도 한다. 본 연구에서는 VOC 제거 효율을 높이기 위해 3가지 기술이 융합된 플라즈마-덤프 연소기(PDC, plasma dump combustor)를 개발하였다. PDC 특성을 파악하기 위해 상부 공급 유량, VOC농도, 공급전력, AC/DC전원 공급에 대한 실험을 수행하였다. Fig. 1은 유량 변화 시 VOC 분해율과 배출되는 가스 성상 및 농도를 측정한 그래프이다. 그래프에서 나타나듯 유량이 증가 할수록 분해율이 떨어지는 모습을 볼 수 있다. 이는 플라즈마-덤프의 분해 원리인 캐비티 영역에서의 체류시간이 짧아지게 되어 처리율이 낮아지기 때문이다. 연소 후 배출가스인 CO2와 CO의 농도변화는 유량이 증가할수록 감소되는 추세를 보이고 있다. 이는 증가된 유량에 의해 공기비가 증가되어 연소율이 떨어지게 되어 CO2생성의 감소와 유량 증가에 의한 희석에 의해 CO농도도 감소하게 된다.