• 설비공학논문집
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• 제28권11호
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• pp.450-457
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• 2016

While many studies on the heat transfer effect of an impinging jet have been published, most studies focus on the downward impinging jet. This study investigates the impinging jet heat transfer phenomenon when water at a temperature of $24^{\circ}C$ impinges on the downward isothermal circular plate at 60, 70, and $80^{\circ}C$ and when the upward round jet nozzle is 4, 6, and 8 mm diameter with a flow rate 3.6, 4.6, and 5.6 L/min, respectively, and when the ratio of the nozzle clearance/nozzle diameter (H/D) is 1. The results showed that, as the nozzle diameter decreases, the heat transfer coefficient increases at a constant flow rate. The correlation equation of $Nu_r$, $Pr_r$, and $Re_{jg}$ is obtained in the impinging and constant velocity flow region $(Nu_r/Pr^{0.4}_r)Dr=4.6[Re_{jg}(r/R_c)Dr]^{0.8}$ at all flow rates, in the deceleration and falling flow regions $(Nu_r/Pr^{0.4}_r)Dr=42.7{\mid}Re_{jg}(r/R_c)Dr-345.7{\mid}^{0.3}$ at 3.6 L/min, $(Nu_r/Pr^{0.4}_r)Dr=92.4{\mid}Re_{jg}(r/R_c)Dr-16.8{\mid}^{0.2}$ at 4.6 L/min, and $(Nu_r/Pr^{0.4}_r)Dr=322.4{\mid}Re_{jg}(r/R_c)Dr-536.2{\mid}^{0.01}$ at 5.6 L/min.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제26권4호
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• pp.325-336
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• 2000

Bone morphogenetic protein-2/4 are members of Transforming Growth Factor-$\beta$(TGF-$\beta$) superfamily and they may induce formation of cartilage and bone in vivo. This study was performed to investigate the cellular target and period of action of BMP-2/4 and understanding of actions of BMP-2/4 at cellular level. The appearance of BMP-2/4 during healing of mandibular and periodontal defect in rat was evaluated immunohistochemically. 40 Sprague-Dawley strain white male rats, each weighing about 300gm were used. Bony defect was performed in the mandible and they were sacrificed at the day of 3rd, 10th, 20th, 30th after operation. The specimens were harvested and examined histologically and immunohistochemically by localization of anti-BMP-2/4. The results were as follows: 1. Woven bone was observed at 10th day and perfect healing of defect with compact bone and periodontal ligment space at 30th day. 2. Osteoprogenitor cells, osteoblastic cells and periosteum were positive reaction to immunohistochemical stain at 10th day. 3. Cells of bone marrow space and surface cells of osteocytes and cementoblasts were positive reaction to immunohistochemical stain at 20th day. 4. Newly formed osteocytes and cementocytes were positive reaction to immunohistochemical stain at 30th day. From the above findings, we could conclude that BMP-2/4 acted significant roles as factors of induction, proliferation and differentiation during bone healing process.

• 대한전자공학회논문지TC
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• 제45권3호
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• pp.1-6
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• 2008

본 논문에서는 2.4GHz 및 5GHz의 이중대역에서 동작하는 I/Q 모듈레이터를 설계하였다. 광대역 믹서에 $90^{\circ}$ 위상천이기를 이용하여 quadrature 신호를 입력하여 베이스밴드 신호를 변조된 RF 신호로 출력한다. 제안한 I/Q 모듈레이터의 변환 손실은 2.4GHz에서 약 15dB이고 5.8GHz 대역에서 약 16dB이다. 사이드밴드 억압특성은 2.4GHz/5GHz에서 각각 15dBc, 16dBc이며, carrier suppression은 두 대역에서 약 40dBc이다. 또한 11Mbps 의 QPSK 신호입력시의 EVM 특성은 2.4GHz에서 약 8.5%, 5GHz에서 10% 이며, 반송파 억압은 두 대역에서 40dB 이상으로, 무선 랜 신호를 인가시 출력 스펙트럼 규격을 만족하였다.

• 한국식품과학회지
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• 제10권1호
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• pp.36-45
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• 1978

맥백혈구(脈白血球) Lysosomal 효소를 pH(7.0, 4.0), 온도($37^{\circ}C$, $4^{\circ}C$) 및 처리기간($37^{\circ}C$에서 12 24시간, $4^{\circ}C$에서 36 168시간)을 달리하여 처리(處理)한 우(牛)의 요근조직(腰筋組織)의 변화(變化)에 대(對)하여 endomysial connective tissue, sarcolemma 및 transverse ridge등 근(筋)섬유 표면조직(表面組織)의 변화(變化)를 SEM으로 관찰한 바, 처리온도(溫度)에 관계(關係)없이 pH 7.0에서는 endomysial connective tissue, sarcolenna 및 transverse ridge의 분해(分解)를 나타내어 이 효소의 높은 역가(力價)를 보였으나, pH4.0에서는 이들 표면조직(表面組織)에 변화(變化)가 없었으며 특(特)히 transverse ridge는 $37^{\circ}C$에서 24시간, 그리고 $4^{\circ}C$에서 7일간 처리(處理)하여도 변화(變化)를 나타내지 않아 안정(安定)됨을 보였다.

• Korean Journal of Acupuncture
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• 제27권1호
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• pp.31-47
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• 2010

Objectives: To investigate the anti-inflammatory effects of cultivated wild ginseng pharmacopuncture in lipopolysaccharide (LPS)-induced inflammatory rat model. Methods: Sprague-Dawley rats were divided into 4 groups; LPS control (n=6), LPS+cultivated wild ginseng pharmacopuncture at CV4 (n=6), LPS+cultivated wild ginseng pharmacopuncture at CV17 (n=6), and LPS+cultivated wild ginseng pharmacopuncture at Ex-HN1 (n=6). Pharmacopuncture (0.1 ml) was given every two days for 4 weeks followed by inflammation induction by peritoneal LPS injection (5 mg/kg). Blood, liver tissue, and peritoneal lavage fluid were taken and proinflammatory cytokines and other related factors were analysed. Results: Compared with the control group, CV4 and Ex-HN1 pharmacopuncture groups significantly attenuated plasma IL-$1{\beta}$, IL-6, and TNF-$\alpha$ increase at 2h and 5h after LPS injection (P<0.05). A significant difference from control group emerged at 5 h for plasma IL10 (P<0.05). For liver cytokines analyzed at 5 h after LPS injection, only CV4 pharmacopuncture group showed significant difference in TNF-$\alpha$ and IL-10 (P<0.05). Blood CD4/CD8 ratio and the phagocytic activities of polymorphonuclear neutrophils were not different from those of control group in all pharmacopuncture groups (P>0.05). CV4 pharmacopuncture significantly attenuated increase of plasma ${NO_3}^-/{NO_2}^-$, Intracellular adhesion molecule-1 (ICAM-1), cytokine-induced neutrophil chemoattractant-1 (CINC-1), and prostaglandin $E_2$ ($PGE_2$) compared with the control group (P<0.05). Monocyte chemoattractant protein-1, $PGE_2$, and CINC-1 level of CV4 pharmacopuncture group was significantly different from those from the control group (P<0.05). Conclusions: These results indicate that cultivated wild ginseng pharmacopuncture at CV4 may have a potent anti-inflammatory effect in an LPS-induced inflammatory rat model.

• Korean Journal of Ophthalmology
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• 제32권6호
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• pp.483-487
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• 2018

Purpose: To compare the characteristics and surgical outcomes in patients with tenacious proximal fusion (TPF) and high accommodative convergence/accommodation ratio (AC/A) types of intermittent exotropia. Methods: This study retrospectively enrolled 40 patients with intermittent exotropia, 23 with TPF and 17 with high AC/A. Binocular function was evaluated by Worth's 4-dot test. Patients underwent lateral rectus recession, and surgical outcomes were compared. Surgical success was defined as less than ${\pm}10$ prism diopters (PD) at 12 months postoperatively. Results: The proportion of diplopia at near, evaluated by Worth's 4-dot test, was significantly higher in patients with high AC/A than in those with TPF (35.3% vs. 4.3%, p = 0.029). The mean preoperative angles of deviation in TPF and high AC/A types were $28.3{\pm}4.4$ and $28.8{\pm}4.5PD$ at distances, and $14.7{\pm}4.2$ and $15.1{\pm}4.1PD$ at near. Twelve months after surgery, the mean angles of deviation in TPF and high AC/A types were $2.9{\pm}9.8$ and $1.2{\pm}9.6PD$, respectively, at distance and $1.7{\pm}7.7$ and $-1.3{\pm}11.3PD$ at near. The surgical success rates were similar in the TPF and high AC/A types (74.0% vs. 64.7%). Five (21.7%) patients with TPF and 2 (11.8%) with high AC/A type experienced recurrence, with consecutive esotropia occurring in 1 (4.3%) patient with TPF and 4 (23.5%) patients with high AC/A. Conclusions: The proportion of diplopia at near was higher in patients with high AC/A type than in those with TPF intermittent exotropia. However, the surgical success rates were not significantly different between the types.

• 전자공학회논문지 IE
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• 제49권2호
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• pp.46-51
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• 2012

AT-DMB 시스템의 신호 전송은 향상계층은 채널등화를 거친 Coherent Detection을 사용하지만 기본계층은 T-DMB와 마찬가지로 차동변복조를 사용한다. 본 논문에서는 이와같은 구조에서 어차피 향상계층 수신을 위하여 사용되는 채널추정 결과를 기본계층에 적용하여 기본계층의 수신성능을 향상시킬 수 있음을 보여준다. 제안하는 방법은 AT-DMB 수신단의 차동복조앞단에서 수신신호에 채널등화를 적용한 후 수신신호 성상도를 가장 가까운 ${\pi}$/4-shift DQPSK 성상도점으로 집중화시킨 후 차동복조를 적용함으로서 코딩을 적용하지 않은 상태에서 AWGN $10^{-4}BER$ 기준으로 약 2dB 성능향상을 얻을 수 있음을 보였다.

• 한국보건간호학회지
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• 제2권2호
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• pp.81-98
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• 1988

The purpose of this study was to fine out the general physical status of the neonates, and to identify the risk factors of the mothers and the neonates which were significantly related to the neonatal diseases during hospitalization. The data were obtained from clinical records of 1098 neonates born in Seoul Red cross Hospital between January 1st of 1984 and December 31th of 1986. The results of this study were summarized as follows: 1. General characteristics of the maternal group. 1) The average of maternal age was 26.6 years, the $91.7\%$ of the mothers de liveried at the age of 20-34 years old. 2) The distribution of the types of delivey were as follows : spontaneous delivery $39.9\%$, cesarean section $32.4\%$, vaccum extraction $25.7\%$, and breech delivery$2.0\%$. 3) The $40.3\%$ of the total de liveried mother had experienced abortion. 4) The $42.3\%$ of the total deliveried mother had one or more obstetric risk factors. 2. General characteristics of the neonatal group. 1) In the distribution of sex, male was $49.4\%$, female $50.6\%$. 2) The average of birth weights was 3,020gm. The distribution of birth weight were as follows; nomal weight $85.5\%$, low birth weight $12.7\%$ and high birth weight $2.5\%$. 3) The average of gestational age was 39.2 weeks. The distribution of gestational age were as follows; full term $77.4\%$, preterm $13.7\%$, and postterm $8.9\%$. 4) The average of Apgar Score was 9.0 at one minute and 9.6 at five minutes. 5) The $5.7\%$ of the neonates had one or more neonatal risk symptoms and signs at birth. 3. Apgar Score by the maternal and neonatal factors. In Apgar Score at one minute, normal group was higher than that of abnormal group. Apgar Score at five minutes was slightly higher than that at one minute. 4. The distribution of the maternal risk factors and the neonatal risk factors. 1) The total numbers of the maternal risk factors were 1376. The distribution of the maternal risk factors were as follows: obstetric factor $33.7\%$, abortion $32.2\%$, breech and cesarean section delivery $27.5\%$ and maternal age under 19 years and over 35 years $6.6\%$. 2) The total numbers of the neonatal risk factors were 517. The distribution of the neonatal risk factors were as follows: gestational age under 37 weeks and over 42 weeks $48.0\%$, birth weight under 2500gm and over 4000gm $12.2\%$, Apgar score under 4 at one munute $6.4\%$ and Apgar score at five munutes $2.7\%$. 3) The total numbers of the obstetric risk factors were 661. The types of the obstetric risk factors were meconium stained amniotic fluid $22.0\%$, premature rupture of membrane $17.5\%$. absence prenatal care $14.1\%$, unmarried pregnancy $10.3\%$, placenta problem $9.0\%$, toxemia $8.0\%$. 4) The total numbers of the neonatal risk symptoms and signs at birth were 83. The types of the neonatal risk symptoms and signs were respiratory distress $65.1\%$, neonatal apnea $14.4\%$, convulsion $13.3%$, meconium aspiration syndrome $4.8\%$, cyanosis $2.4\%$. 5. The relationship between the maternal risk factors and the neonatal risk factors. 1) Maternal age under 19 years or over 35 years was significantly related to Apgar Score under 4 at 5 minutes. 2) Breech delivery or cesarean section was significantly related to neonatal risk factor at birth such as birth weight, gestational age, Apgar Score at one minute and at five minutes. and neonatal risk symptoms and signs. 3) Obstetric risk factors were significantly related to the neonatal risk factors at birth. 4) Abortion was not related to the neonatal risk factors. 6. The relationship between neonatal diseases during hosptalization and the maternal or the neonatal risk factors. 1) The total numbers of neonatal diseases during hospitalization were 281. The distribution of neonatal diseases were as follows: birth trauma $38.1\%$, infectious disease $31.3\%$, hematologic disease $21.4\%$, respiratory disease $6.0\%$, neurologic disease $2.5\%$. cardiovascular disease $0.7\%$. 3) Most maternal risk factors except abortion were significantly related to neonatal diseases. 4) Most neonatal risk factors at birth were significantly related to neonatal diseases.

• 한국주조공학회지
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• 제2권4호
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• pp.2-8
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• 1982

The behavior of sand and mold at high temperatures was generally agreed to importantly affect the quality of castings made. By changing water content through 2,4,6 and 8%, and bentonite content through 5,7,9 and 11%, specimens have been made according to the respective composition. Specimens have been subjected to hot compressive strength and thermal expansion at 400, 600, 800 and $1000^{\circ}C$ respectively. The results obtained were as follows ; 1. At each temperature, thermal expansion decreased and hot compressive strength increased with the increase in water content. 2. After thermal expansion was peaked at approximately $1000^{\circ}C$ the contraction and maximum hot compressive strength appeared. 3. At each temperature, maximum hot compressive strength appeared 2%, 4,6% and 8% water content for 7%, 9% and 11% bentonite content respectively. 4. When 2% $H_2O$ was added, though bentonite content was increased, hot compressive strength did not rarely change. 5. Until the thermal expansion was completed the required time was 15-18 minutes at $400^{\circ}C$ and $600^{\circ}C$, and 10-13 minutes at $800^{\circ}C$. At $1000^{\circ}C$, the required time was 7-9 minutes in order to gain the maximum expansion, after that, contraction proceeded during 3-4 minutes before expansion was completed.

• Journal of electromagnetic engineering and science
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• 제10권1호
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• pp.6-12
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• 2010

In this paper, highly efficient class-F power amplifiers(PAs) with harmonic-controlling transmission lines(TLs) were built for cellular and WLAN applications at 840 MHz and 2.4 GHz each. Also, based on these single-band PAs, a dualband class-F PA was designed after a careful investigation into the harmonics of the two frequencies. The harmonic-controlling TL was designed for the class-F operation at dualband by switching the length of the shunt $\lambda$/4 TL part, while the series $\lambda$/4 TL is optimized for both frequencies. To verify the performance, two class-F PAs optimized at each frequency and a dualband class-F PA at the corresponding frequencies were built with the secondand the third-harmonic control circuits at each frequencies. As a result, the PA#1 at 840 MHz has a peak drain efficiency of 81.2 % with an output power of 24.4 dBm, while the PA#2 at 2.35 GHz shows a drain efficiency of 94.5 % with an output of 22.8 dBm. Finally, the dualband class-F PA#3 showed 60.5 % and 50.9 % drain efficiencies at 840 MHz and 2.4 GHz, with powers of 23.8 dBm and 19.62 dBm, respectively.