• 한국의류산업학회지
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• 제24권6호
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• pp.812-824
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• 2022

This study proposes to develop a 3D printed re-entrant(RE) strip by shape memory thermoplastic polyurethane that can be deformed and recovered by thermal stimulation. The most suitable 3D printing infill density condition and temperature condition during shape recovery for mechanical behavior were confirmed. As the poisson's ratio indicated, the higher the recovery temperature, the closer the poisson's ratio to zero and the better the auxetic properties. After recovery testing for five minutes, it appeared that the shape recovery ratio was the highest at 70℃. The temperature range when the shape recovery ratio appeared to be more than 90% was a recovery temperature of more than 50℃ and 60℃ when deformed under a constant load of 100 gf and 300 gf, respectively. This indicated that further deformation occurred after maximum recovery when recovered at a temperature of 80℃, which is above the glass transition temperature range. As for REstrip by infill density, a shape recovery properties of 100% was superior than 50%. Additionally, as the re-entrant structure exhibited a shape recovery ratio of more than 90%, and exhibited auxetic properties. It was confirmed that the infill density condition of 100% and the temperature condition of 70℃ are suitable for REstrips for applying the actuator.

• 설비공학논문집
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• 제15권8호
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• pp.690-696
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• 2003

This paper presents the heat recovery performance of water fluidized-bed heat exchanger. Temperature and humidity ratio of waste gas are considered as important parameters in this study. Therefore, the heat recovery rate through water fluidized-bed heat exchanger for exhaust gases with various temperatures and humidity ratios can be estimated from the results of this study. Mass flow ratio (the ratio of mass flow rate of water to that of gas) and temperature of inlet water are also considered as important operating variables. Increase of heat recovery rate can be obtained through either high mass flow ratio or low temperature of inlet water with resultant low recovered temperature. The heat recovery performance with the mass flow ratio of about up to 10 has been investigated. The effect of number of stages of water fluidized-bed on the heat recovery performance has been also examined in this study.

• Tribology and Lubricants
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• 제31권3호
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• pp.102-108
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• 2015

In this research, we experimentally investigated the sealing performance of elastomeric rotary lip seals for washing machines. In general, NBR is used as a material for elastomeric rotary lip seals in washing machines, but the mixing formula of the rubber material can affect the sealing performance. In this study, we manufactured rotary lip seals using three kinds of NBRs with a different mixing formula, and examined the sealing performance using an acceleration test mode. The results of an SEM investigation into the surfaces of three kinds of specimens showed a much smaller wear volume and better sealing performance for the specimens with smaller particle sizes of mixing composition than for the specimen with the larger. Repeated deformation and recovery by the shaft-to-seal eccentricity on rotation were shown to cause a phase difference in the rubber material, and we measured the recovery ratio to find the influence of this phase difference on the sealing performance. As another method for checking the phase difference, we also measured tan ä, and a lower tan ä was revealed as the recovery ratio increased for each specimen. Specimens with a higher recovery ratio (lower tan ä) were shown to have a better sealing performance. Consequently, specimens with a smaller particle size in the mixing composition had a better sealing performance because they show a higher recovery ratio.

• 한방안이비인후피부과학회지
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• 제16권1호
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• pp.141-153
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• 2003

Introduction : The causes of sudden sensorineural hearing loss have not been detemined with precision until recently, but viral infections and vascular insufficiencies, such as vascular spasm, occlusion of sludging of erythrocytes were considered as major factors. The treatment has not been determined with precision until recently. It is similar to dizziness(眩暈). sudden dcafncss(暴聾) and congestion-fire deafness(痰火聾) in Oriental Medicine. It is very rare that someone has sudden hearing loss and visit Oriental Medicine Clinic right that time. But we expect if they take a Oriental treatment on thc right time. more effective for their symptom. Subjects : Following conclusions were reached by measuring results of oricntal medical treatments for 40 patients who visited the clinic between January of 2000 and December of 2002, and received treatments continuously for more than 1 months of time. Methods : Among the selected 40 patients. 30 patients belong to Group Ⅰ, which consisted of patients who had already visited a general hospital prior to visiting this clinic, achieved no recovery at all from sudden deafness despite going through more than 5 days of hospitalized treatments of steroidal medications. Group Ⅱ was consisted of 10 patients of sudden deafness who did not experience any steroidal treatments from other hospital prior to the oriental medical treatment. Results and conclusion : According to differentiation of syndrome. among 30 patients of the Group Ⅰ. 21 were categorized as excess syndrome patients and remaining 9 as deficiency syndrome paticnts. Among 10 patients of For Group Ⅱ, 5 were excess syndrome patients and remaining 5 were deficiency syndrome patients. Among Group Ⅰ, recovery ratio of excess syndrome patients was 47.7$\%$ and deficiency syndrome patients was 44.4$\%$ adding up recovery ratio of the group to be 46.1$\%$. Among Group Ⅱ, recovery ratio of excess syndrome patients was 80$\%$ and deficiency syndrome patients was 100$\%$ adding up recovery ratio of the group to be 90$\%$. Oriental medical treatments are generally more effective(90$\%$ recovery ratio) for Sudden Deafness than steroidal treatments. Oriental medical treatments are almost equally effective for both excess syndrome patients and deficiency syndrome patients. However, steroidal treatments for excess syndrom patients(45$\%$ recovery ratio) is much less effective than deficiency syndrome patients(73$\%$ recovery ratio). This indicates that steroidal treatments should be applied selectively to deficiency syndrome patients if applied at all. Even for patients with sudden deafness which hospitalized steroidal treatments did not result in any recovery at all, oriental medical treatments were able to achieve 46.1$\%$ recovery ratio.

• Journal of Biosystems Engineering
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• 제22권2호
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• pp.177-188
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• 1997

A pepper harvester using a pair of counter rotating helically wound cylinders as a pepper removal mechanism has been developed. Pepper harvesting by machines under the customary cultivation practice was expected to lower land productivity, that most farmers were concerned about. As one way to compensate for loss in land productivity by machine harvest, experts on pepper cultivation suggested change of both varieties and plant density per area. From the view of machine design, their suggestion implied that distance between rows should be narrower and height of the pepper removal mechanism could be shorter. Experiments to improve perfect pepper recovery ratio and to reduce size of the pepper removal mechanism was accomplished. In order to be a economically feasible harvester, minimum pepper recovery ratio was required to be greater or equal to 80%. The research goal was achieved by both reducing the diameter of the wire-helices from 30 cm to 18 cm and increasing rotational speed of the wire-helices up to 425 rpm. The best perfect pepper recovery ratio was 82.3%. Validity of experiment design and interpretation on statistical analysis were discussed. To understand the pepper removal mechanism properly, a pepper removal theory based physics was judged to be necessary.

• Journal of Yeungnam Medical Science
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• 제40권3호
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• pp.252-258
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• 2023

Background: The purpose of this study was to investigate whether postoperative cystography findings can predict early and longterm recovery from incontinence after radical prostatectomy (RP), compared with the other cystography parameters. Methods: I retrospectively reviewed 118 patients who underwent robot-assisted RP (RARP) for localized prostate cancer at single institution between January 2016 and April 2021. One hundred and seven patients were included in the study. Postoperative cystography was routinely performed 7 days after surgery. The bladder neck to pubic symphysis ratio, vesicourethral angle, and bladder neck anteroposterior length (BNAP) ratio (the bladder neck-posterior margin distances divided by the anteroposterior lengths) were evaluated. Continence was defined as cessation of pad use. The association between these variables and urinary incontinence was also analyzed. Results: The urinary incontinence recovery rates 1, 3, 6, and 12 months after RARP were 43.92%, 66.35%, 87.85%, and 97.19%, respectively. Multivariate logistic regression analysis demonstrated that a lower BNAP ratio and wider vesicourethral angle were significantly associated with continence restoration at 1, 3, and 6 months after surgery. In addition, in terms of days of pad usage, lower BNAP ratio, wider vesicourethral angle, and bladder neck preservation were significantly associated with recovery from urinary incontinence within 12 months as assessed by Cox proportional hazard analysis. Conclusion: This study demonstrated that vesicourethral angle and BNAP ratio were independent predictors of early recovery from post-prostatectomy incontinence. I suggest that both the sagittal and coronal views of postoperative cystography help anticipate early continence restoration after RARP.

• 대한인간공학회지
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• 제36권5호
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• pp.535-543
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• 2017

Objective: This study was designed to identify factors affecting pilots' +Gz tolerance recovery from +Gz induced exhaustion. Background: +Gz tolerance of pilots has been considered as a crucial factor to fly the modern high performance fighter aircrafts. However, the factors affecting pilots' G-tolerance recovery from +Gz induced exhaustion have not been examined in the acceleration research community. Method: A centrifuge profile consisting of a high +Gz run for pilot's exhaustion and a low +Gz run for pilot's recovery and another high +Gz runs for pilot's second exhaustion was designed. The subjects' +Gz tolerance recovery ratio was measured by ratio of second high +Gz run time to the first high +Gz run time. The subjects' +Gz tolerance recovery rate was measured by dividing the subjects' +Gz tolerance recovery ratio by the low +Gz run time. The subjects' G-tolerance recovery rate was analyzed with respect to the subjects' personal factors including subjects' anthropometric and physiologic characteristics, flight time, flying aircraft type and so on. Results: The subjects' previous three-month flight hours (r=-0.336, p=0.039), six-month flight hours (r=-0.403, p=0.012) and one-year flight hours (r=-0.329, p= 0.044) correlated with the subjects' G-tolerance recovery rate. Conclusion: The subjects' G-tolerance recovery rate is clearly related to the subjects' previous flight hours. However, the subjects' anthropometric and physiologic characteristics do not show any statistically significant correlation with the subjects' G-tolerance recovery rate. Application: This research provides a safety critical insight to aviation community by identifying the factors to affect the gravity-induced loss of consciousness (GLOC) of pilots.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제41권
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• pp.61.1-61.8
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• 2019

Background: The prognosis of recovery following microneurosurgery for injured lingual nerves varies among individual cases. This study aimed to investigate if recovery ratios of sensory and taste functions are improved by the microneurosurgery within 6 months after lingual nerve injury. Methods: We retrospectively assessed 70 patients who underwent microneurosurgery at the Wakayama Medical University Hospital for lingual nerve injuries between July 2004 and December 2016. Sensory and taste functions in lingual nerves were preoperatively evaluated using a static two-point discrimination test, an intact superficial pain/tactile sensation test, and a taste discrimination test. They were evaluated again at 12 and at 24 months postoperatively. The abundance ratio of Schwann cells in the excised traumatic neuromas was analyzed with ImageJ software following immunohistochemistry with anti S-100β antibody. Results: In early cases (microneurosurgery within 6 months after the injury), recovery ratios of sensory and taste functions were not significantly different at 24 months after microneurosurgery compared with later cases (microneurosurgery more than 6 months after the injury). Meanwhile, the ratio of patients with taste recovery within 12 months after microneurosurgery was significantly decreased in late cases compared with early cases. The abundance ratio of Schwann cells in traumatic neuroma was also significantly lower in later cases. Conclusion: Microneurosurgery more than 6 months after lingual nerve injury did not lead to decreased recovery ratio of sensory and taste functions, but it did lead to prolonged recovery of taste. This delay may be associated with a decrease in the abundance ratio of Schwann cells in traumatic neuromas.

• Journal of Biosystems Engineering
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• 제32권6호
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• pp.395-402
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• 2007

This study was carried out as basic researches to develop the leaf vegetable harvester. This study was conducted to investigate physical and rheological properties of bundled leaf vegetables with stem (Chinese leek, Crown daisy and Chamnamul) as test materials held and picked-up by a machine. Stress-strain behavior, stress relaxation, and strain recovery for the bundled materials were analyzed using simple Maxwell model. Physical and rheological properties of the materials were investigated by measuring rupture load, deformation and stress experimentally. Also, strain recovery time when unloading was measured using super high speed camera. Recorded recovery time for stress-strain behavior was0.026 s for Chinese leek with liner strain recovery, 0.046 s for Crown daisy and 0.05 s for Chamnamul with non-linear strain recovery. Furthermore, the strain recovery time for permanent deformation was 0.026 s, 0.046 s, and 0.05 s for Chinese Leek, Crown daisy and Chamnamul, respectively. Finally, strain recovery time and strain recovery ratio for the test materials were 0.17 s, 60.4% in Chinese leek, 0.12 s, 55.3% in Crown daisy, 0.15 s, 58.7% in Chamnamul. Here strain recovery time means that how fast the test materials are recovered from initial deformation and strain recovery ratio means how much the test materials are recovered from initial deformation. The above results show that the test materials can be held enough and moved by the belts.

• Applied Biological Chemistry
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• 제40권2호
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• pp.107-111
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• 1997

Protopectinase(PPase)는 식물 세포벽의 protopectin을 분해하는 효소로서 식품의 가공에 이용될 수 있는 효소이다. PPase의 산업적 응용을 위하여 PPase를 생산하는 미생물 Bacillus subtilis IFO 12113의 배양여액에 acetone, methanol, ethanol을 각각 처리하여 PPase를 회수하는 연구를 수행하였다. Acetone의 경우, 배양여액 대 acetone을 1:1 (v/v) 비율로 첨가했을 때 효소는 59.2%가 회수되었으며 정제도는 1.7배 이었다. Methanol의 경우, 1:2(v/v) 비율로 처리하였을 때, 효소는 100% 회수되었으며 비활성도로 본 정제도는 4.0배 증가하였다. Ethanol의 경우에 1 :0.5 (v/v) 비율로 처리한 것을 원심분리시켜 침전물을 제거하고, 그 상등액에 최종 ethanol 비율을 1:1(v/v)까지 처리했을 때, 효소의 회수율은 68%를 나타냈으며 비활성도는 13.5배 증가하였다. 세균의 배양여액으로부터 PPase의 회수에는 methanol 처리가 가장 효율적이었으나, 산업적 응용을 위하여 정제효과까지 고려하면 ethanol처리가 가장 적절하였다.