• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.4
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• pp.201-206
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• 2015

The MVR was theoretically modeled by performing the polytropic process, and the polytropic coefficient was estimated by using the performance curve provided by the manufacturers. The TVR was investigated by applying the conservation equations to the movement of fluids inside the TVR. The size of the nozzle and diffuser was determined. Theoretical MVR and TVR modeling was verified by comparing the results of the model with the available design data. Besides, the effects of multi-staging of the MVR on power consumption, and the effects of suction and primary pressure on the sizing of TVR were investigated.

• Korean Circulation Journal
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• v.53 no.11
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• pp.775-786
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• 2023

Background and Objectives: Tricuspid valve (TV) repair techniques other than annuloplasty remain challenging and frequently end in tricuspid valve replacement (TVR) in complicated cases. However, the results of TVR are suboptimal compared with TV repair. This study aimed to evaluate the clinical effectiveness of TV edge-to-edge repair (E2E) compared to TVR for severe tricuspid regurgitation (TR). Methods: We retrospectively reviewed 230 patients with severe TR who underwent E2E (n=139) or TVR (n=91) from 2001 to 2020. Clinical and echocardiographic results were analyzed using inverse probability of treatment weighting analysis and propensity score matching. Results: The two groups showed no significant differences in early mortality and morbidities. During the mean follow-up of 106.2±68.8 months, late severe TR and TV reoperation rates were not significantly different between groups. E2E group, however, showed better outcomes in overall survival (p=0.023), freedom from significant tricuspid stenosis (TS) (trans-tricuspid pressure gradient ≥5 mmHg, p=0.021), and freedom from TV-related events (p<0.001). Matched analysis showed consistent results. Conclusions: E2E for severe TR presented more favorable clinical outcomes than TVR. Our study supports that E2E might be a valuable option in severe TR surgery, avoiding TVR.

• Journal of Embryo Transfer
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• v.11 no.2
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• pp.103-109
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• 1996

The aim of this study was to evaluate the effect of recombinant bovine somatotropin (bST; Boostin-S, LG Chem) treatment with FSH (Super OV) or PMSG on superovulatory response for transvaginal ultrasound-guided oocyte retrieval (TVR) in calves. Eight Korean Native Cattle(KNC) heifer calves; 150 to 240 days old; were randomly assigned to four treatment groups: 1) FSH(75 mg); 2) FSH (75 mg) + bST(500mg) 3) PMSG(1;000 IU); 4) PMSG(1, 000 IU) + bST(500 mg). Experimental calves in group 1 (n=2) and 2(n=2) were weekly superovulated for 4 consecutive weeks with daily injection of FSH for 3days and the next day subjected to TVR session. Animals in group 3 (n=2) and 4(n=2) were weekly stimulated for 4 consecutive weeks with a single dose of 1, 000 IU PMSG. TVR was performed on 72 hours after PMSG injection. Calves in group 2 and 4 was received injection of 500 mg of bST every 10 days. At each TVR session, follicle number and size were recorded; the oocytes collected and graded according to cumulus and cytoplasm investment. Collected oocyte were determined viable oocyte according to morphological quality with granulation of oocyte and number and status of cumlulus cells. IVM and IVF were performed and assessed cleavage rate on day 3 after fertilization. A Sonovet 600(Medison, Co., Ltd) realtime ultrasound scanner with a 6.5 MHz convex transducer, fixed at the tip of 500 mm estended handle equipped with a needle guide was used in collecting oocyte. Differences between groups were analysed by chi-square test. The population of large follicle ($\geq$5 nun) and aspiration rate were not significant different among the 4 groups. But, the number of small follicles (<5 mm) and aspirated oocyte in the KNC calves treated with bST were 1.3~1.6 times higher than in KNC calves treat with FSH or PMSG alone. In conclusion, the administration of bST with FSH or PMSG at superovulation for TVR in calves was increase the nurnber of small follicle which was influenced the number of aspiratable follicle.

• Journal of Chest Surgery
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• v.14 no.4
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• pp.369-380
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• 1981

In this department 504 cases of valve replacement were done since 1968 to the end of October 1981. Since October 31, 1978 to the end of October 1981 ,333 Ionescu-Shiley bovine pericardial xenograft bioprosthetic cardiac valves were replaced in 265 patients. There were 149 males and 116 female. Ages ranged from 2 to 63 years with 25 cases under 15 years of age. Among 265 cases of Ionescu valve replacement there were 157 MVR, 36 VAR, 6 TVR, 45 MVR+ AVR, 16 MVR+TVR and 5 MVR+AVR+TVR cases with mortality of 5.7%, 8.3%, 16.7%, 8.9%, 18.8% and 20% for each group respectively. Over all mortality rate in 265 Ionescu valve replacement cases was 7.9% with 21 total deaths. Main causes of operative deaths were due to LCOS in 7, bleeding in 5, arrhythmia in 3, air embolism in 2,and heart block in 2 cases. There were 12 late complications with 6 deaths. Over all long-term survival rate was 89.8%. MVR showed the highest long-term survival rate with 92.4%, and MVR+AVR+TVR the lower with 80% lower with 80%.Average follow-up period was 14 month duration. Twenty five congenital anomaly cases were operated with Ionescu-valve replacement that consisted of 7 VSD+AI, and 5 Ebstein anomaly cases with over all operative mortality of 16% and late mortality of 14.3% among 21 operative survivors. There were 25 Ionescu valve replacement cases in pediatric patients under the age of 15 years, with 4 operative deaths. Fourteen MVR, 7 AVR, and 3 TVR cases were found. Even though long-term follow-up study was short in postoperative period with total of 33~.0 months among 244 operative survivors ranging one to 36 months, the late survivors showed beneficial long-term results two thromboembolic episodes in 244 patients were found. More cases and longer term follow-up study are warranted for valve replacement in pediatric and TVR cases with Ionescu-valves which have advantageous hemodynamic structures compared with other bio-prosthetic heart valves.

• The Magazine for Energy Service Companies
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• s.40
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• pp.16-19
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• 2006

국내 유일의 이산화티타늄(TiO₂) 생산업체인 코스모화학(주)이 울산 온산사업장에 최근 농축시스템 TVR을 도입, 연간 14억원의 스팀비용을 절감할 것으로 보인다. 고유가와 저가 중국산 공세에 대응하기 위한 에너지비용 절감차원에서 도입한 TVR시스템은 스팀 사용량의 50%를 절감하고도 품질수준을 한 단계 업그레이드 한 것으로 평가받고 있다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.5
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• pp.543-549
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• 2011

An underwater speaker was developed for use as an acoustic deterrent device that transmits acoustic energy through the water omnidirectionally over a broadband frequency range to eliminate marine mammal attacks and to prevent physical damage to the inshore and coastal fishing grounds of Korea. The underwater speaker was constructed of two vibration caps machined from 6061-T6 aluminum alloy and a stack of PZ 26 piezoelectric ceramic rings (Ferroperm Piezoceramics A/S) connected mechanically in series and electrically in parallel. The performance characteristics of the underwater speaker were measured and analyzed in an experimental water tank of $5\;m{\times}5\;m{\times}6\;m$. The peak transmitting voltage response (TVR) was measured at 11.16 kHz with 163.45 dB re $1\;{\mu}Pa$/V at 1m. The underwater speaker showed a near omnidirectional beam pattern at the peak TVR resonance frequency. The usable frequency range was 4-25 kHz with a lower TVR limit of approximately 140 dB. We conclude that this underwater speaker could be satisfactorily used as an acoustic deterrent device against marine mammals, particularly the bottlenose dolphin, to protect catches and fishing grounds as well as the mammals themselves, for example, by keeping them away from fishing gear and/or vessels.

• Journal of Chest Surgery
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• v.16 no.1
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• pp.49-54
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• 1983

Fifty-Seven Cases of tricuspid valve replacement were done from April 1976 to January 1983. Fourteen congenital and 43 acquired cases were found. In 13 cases tricuspid valve alone was replaced with 2 operative deaths and one late deaths. In 35 cases TVR and MVR were done with 6 operative deaths and 6 late deaths. In 9 cases TVR, MVR, and AVR were done with one operative deaths. Over all operative mortality was 15.8% and late mortality 12.3% among the 48 survivors. Over all Survival rate was 71.9% during follow-up period ranging from 8 months to 6 years and 9 months. In every case TVR was done with bioprosthetic xenograft valves.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1994.04a
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• pp.394-398
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• 1994

The aim of the present study was to determine the influence of vibration frequency and muscle contraction level at constant vibration displacement amplitudes on a commonly observed motor response elicited by local vibratory stimulation, i.e., the Tonic Vibration Reflex (TVR). Vibration was applied to the distal tendons of the hand flexor muscles. Changes in activity of the hand flexor and extensor muscles were analyzed as a function of the vibration frequency (40-200 Hz), displacement amplitude(200.mu.m and 300.mu.m peak-to-peak), and the initial contraction level of the flexor muscles (0%, 10%, and 20% of the maximal voluntary contraction: MVC). The main results indicate that the TVR increases with vibration frequency up to 100-150 Hz and decreases beyond, and the TVR attains its maximum at 10% MVC. It appears that high frequency vibration tends to induce less muscle/tendon stress. Such a result is of particular importance for the design of handheld vibrating tools.

• The Magazine for Energy Service Companies
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• s.32
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• pp.60-65
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• 2005

• Proceedings of the ESK Conference
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• 1994.04a
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• pp.49-51
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• 1994

The aims of this study were first to determine the influence of vibration displacement amplitude $(200{\mu}m, 300{\mu}m peak-to-peak)$ at selected frequencies (40-200Hz) on a commonly observed but often undesired motor response elicited bylocal vibratory stimulation, the Tonic Vibration Reflex (TVR). Second, to determine the degree of synchronization of motor unit (MU) activity with vibratory stimuli. Vibration was applied to the distal tendons of the hand flexor muscles. Changes in root- mean-square electromyographic (EMG) activity of the finger and wrist flexor muscles were analyzed both as a function of their initial contraction level (0%, 10%, 20% of the maximal voluntarycontraction: MVC) and as a function of the vibration parameters. The results indicate that the TVR increased with the initial muscle contraction up to 10% MVC: The TVR increased with vibration frequency up to 100-150 Hz and decreases beyond; A significant increase of the TVR with vibration displacement amplitude was observed only for the wrist flexor muscle; MU synchronization at vibration frequency (VF) was found more often in the low frequency range $(f{\leq}100 Hz)$ and tended todecrease beyond; In the high frequency range $(f{\geq}120 Hz)$, MU activity at subharmonic frequency was predominant; The "cut-off" frequency of the synchronization with VF was neither affected by the vibration displacement amplitude nor initial muscle contraction level. The surface EMG turned out to be a useful means to analyze MU synchronization since it is noninvasive, and it can be easily used for analysis of different muscle contraction levels, while single MU technique might have some difficulties at high muscle contraction levels. Furthermore, these results indicate that high frequencyvibration (f>150 Hz) tends to induce less muscle/tendon stress and MU synchronization. Such remarks are of importance for the design of hand-held vibrating tools.ing tools.