• Geomechanics and Engineering
• /
• 제34권1호
• /
• pp.69-86
• /
• 2023

To overcome the dilemma of the [BQ] method's inability to predict mountain tunnel support loads, this study is based on the Hoek-Brown criterion and previous results to obtain the connection equations from GSI scores to each parameter of the Hoek-Brown criterion and the link between the [BQ] scores and the GSI system. The equations were embedded in the Hoek-Brown criterion of FLAC6.0 software to obtain tunnel construction forecasts without destroying the in-situ stratigraphy. The feasibility of the secondary development of the Hoek-Brown criterion was verified through comparative analysis with field engineering measurements. If GSI > 45 with a confining pressure of less than 10 MPa, GSI has little effect on the critical softening factor while we should pay attention to the parameter of confining pressure when GSI < 45. The design values for each parameter are closer to the FLAC3D simulation results and the secondary development of the Hoek-Brown criterion meets the design objectives. If the Class V surrounding rock is thinned with shotcrete or the secondary lining is installed earlier, the secondary lining may act as the main load-bearing structure. The study may provide ideas for rapid prediction of mountainous tunnels in China.

• 대한두개안면성형외과학회지
• /
• 제24권5호
• /
• pp.244-249
• /
• 2023

Fibrous dysplasia (FD) is a rare skeletal disorder characterized by abnormal fibro-osseous connective tissue replacing normal bone. Despite its benign behavior, craniofacial FD can cause morphological disfigurement, headache, and even blindness as a result of the produced mass effect. Surgical resection is recommended when the patient shows apparent clinical symptoms or aggravating facial asymmetry. Postoperative complications have been reported, such as hematoma, surgical site infection, abscess formation, resorption of the bone graft used for reconstruction, and recurrence. An aneurysmal bone cyst (ABC) is a rare benign bony lesion that can occur secondary to preexisting bone tumor. Secondary ABCs in craniofacial FD are extremely rare in the literature, accounting for less than 30, all of which are either case reports or series. We report an extremely rare case of symptomatic secondary ABC arising from craniofacial FD that had been misdiagnosed with abscess formation or recurrence and was surgically removed. Notably, 17 years elapsed between the primary surgery and the complication of secondary ABC. The patient underwent total removal of secondary ABC. After surgery, symptoms were relieved, with no recurrence observed during a 6-month follow-up.

• 한국공간구조학회논문집
• /
• 제8권3호
• /
• pp.53-63
• /
• 2008

본 연구는 개구부를 통해 음향적으로 결합된 공간에서의 잔향특성변화를 축소모형을 이용하여 살펴보았다. 대상공간의 음향적 결합은 정방형의 개구부를 통하여 이루어졌으며, 개구부의 크기, 부실의 흡음력 및 위치를 변화시켜가며 실의 음향특성변화를 측정 분석하였다. 연구결과 동일한 체적을 가진 부실을 통해 주실의 음향특성을 조절하는 경우 부실의 흡음력을 주실보다 현저하게 낮게 하는 것이 넓은 범위의 음향조절이 가능하며, 음향특성을 단계적으로 조절하고자 하는 경우 주실보다 높은 흡음력을 가진 부실을 이용하는 것이 효과적인 것으로 나타났다. 잔향부실의 경우 음원 측에 위치시키는 것이 효과적이며, 개구율이 6.25%이상일 때부터 주실의 음장특성에 중요한 영향을 미치는 것으로 분석되었다. 그러나 개구율이 25%이상으로 증가되면 개구율 증가에 따른 주실의 유의적인 음향특성변화는 더 이상 나타나지 않았다. 흡음부실이 결합되는 경우 음원으로부터 멀리 위치시키는 것이 효과적이었으며, 개구율 3.13%이상일 때부터 주실의 음장특성변화가 가능하였다.

• 대한토목학회논문집
• /
• 제29권1B호
• /
• pp.73-81
• /
• 2009

본 연구에서는 개수로 흐름에서 오염물질 이동 현상에 대한 이차흐름의 영향을 분석하였다. 운동량 방정식과 스칼라 수송 방정식에서의 난류 폐합을 위해 레이놀즈응력 모형 및 GGDH 모형을 사용하였다. 개발된 모형을 이용하여 조 세립상의 횡방향 연속구조를 갖는 개수로 흐름에서의 오염물질 이동에 대한 이차흐름의 영향을 분석하였다. 그 결과, 이차흐름의 영향으로 인해 최대 농도 값의 발생 위치가 이동하는 것으로 나타났으며, 농도 분포 역시 정규 분포에서 거리에 따라 점차 왜곡 되는 것으로 확인되었다. 또한, 이차흐름의 영향으로 자유수면 근처에서는 매끄러운 하상에 비해 거친 하상에서의 오염물질 농도가 더 크게 발생되었으며, 스칼라-흐름률을 계산한 결과, 오염물질의 수직방향 확산은 매끄러운 하상에 비해 거친 하상에서 더 빨리 진행되는 것으로 확인되었다. 한편, 농도 분포 변화에 대한 이차흐름 및 스칼라-흐름률의 영향을 살펴보기 위하여 스칼라 수송률 분석을 수행하였다.

• 사회복지연구
• /
• 제44권2호
• /
• pp.387-407
• /
• 2013

본 연구는 우리나라 외상피해원조전문직인 아동보호전문기관 실무자를 대상으로 업무관련 스트레스인 이차적 외상스트레스와 소진이 서로 다른 주요변수로부터 각자 독립적으로 영향을 받는, 서로 구분되는 개념인가를 살펴보는데 목적을 두었다. 이를 위해 이차적 외상스트레스와 소진에 주요 영향력을 미치는 것으로 알려진 외상노출관련 변인 및 업무조건만족 변인을 집단으로 범주화해서 이들이 종속변수들(이차적 외상스트레스와 소진)에서 평균값의 차이를 지니는가를 확인하는 다변량공분산분석(MANCOVA)을 실시하였다. 성별, 연령, 개인외상력 등 세 가지의 공변량에 대한 통제가 이루어진 후 개체-간 효과검증을 한 결과, 침습과 회피의 이차적 외상스트레스, 그리고 정서탈진과 비인격화의 소진은 실무자 본인이 업무 중 직접 경험하는 신변위협피해의 경험 여부와 업무조건만족정도라는 동일한 요인들로부터 주요한 영향을 받는다는 점이 확인되었다.

• Journal of Electrical Engineering and Technology
• /
• 제8권6호
• /
• pp.1571-1578
• /
• 2013

With the emergence of high-integration array and large area panel process, the need to minimize the generation of particles in the field of semiconductor, LCD and OLED has grown. As an alternative to the conventional roller system, a contactless magnetic conveyor has been proposed to reduce the generation of particles. An EM-PM hybrid which is one of magnetic levitation types is already proposed for the conveyor system. One of problems pointed out with this approach is the vibration caused by the dynamic interaction between conveyor and rail. To reduce the vibration, the introduction of a secondary suspension system which aims to decouple the levitation electromagnet from the main body is proposed. The objective of this study is to develop a dynamic model for the magnetically levitated conveyor, and to investigate the effect of the introduced suspension system. An integrated model of levitation system and rail based on 3D multibody dynamic model is proposed. With the proposed model, the dynamic characteristics of maglev conveyor system are analyzed, and the effect of the secondary suspension and the stiffness and damping are investigated.

• BMB Reports
• /
• 제41권4호
• /
• pp.305-309
• /
• 2008

Cobalt is an essential microelements in many biological processes involving enzymatic activity. We found that $Zn^{2+}$ and $Mg^{2+}$, which are in the active site of native calf intestine alkaline phosphatase (CIP), can be replaced by $Co^{2+}$ directly in solution. The effect of $Co^{2+}$ concentration on the substitution reaction was examined at ratios of [$Co^{2+}$]/[CIP] from 0:1 to 8:1. The quantity of $Zn^{2+}$ in CIP decreased progressively as the ratio was increased, but the amount of $Mg^{2+}$ changed in irrregular fashion. A series of active site models of the reaction mechanism of CIP are proposed. Low pH was found to promote the replacement of $Mg^{2+}$ by $Co^{2+}$. To understand how the substitution affects the enzyme, we also solved the secondary structure of CIP after reaction with $Co^{2+}$ in different conditions.

• 대한기계학회논문집B
• /
• 제23권5호
• /
• pp.687-694
• /
• 1999

An experimental study was carried out in two laboratory-scale reactors to investigate the effect of heating rate on the behavior of flame front in a pulverized coal flame. Each. reactors had different heating mechanisms. For reactor A losing large heat through transparent quartz wall. pulverized coal particles were ignited by secondary air of 1050K. Flame front could be visualized through the transparent wall. Reactor B was insulated with castable refractory to minimize the heat loss through the reactor wall and accompanied with secondary air of 573K. Flame front was estimated from the gas temperature and species concentration measured using R-type thermocouple(Pt-Pt/Rh 13%) and gas chromatograph at various coal-air ratios and swirl intensities. The flame front position was closely related with the magnitude of heating rate. The heating rate for lifted flame was of the order of $10^4$ to $10^5K/s$ and for coal Ignition at least over $10^4K/s$. The heating mechanism had little impact on the extinction limits. The weak swirl number of 0.68 forced the flame front to move toward the upstream by the rapid mixing of coal and air. The primary/secondary momentum ratio was an inappropriate variable to distinct the liftoff of flame.

• 한국동물학회지
• /
• 제8권2호
• /
• pp.23-27
• /
• 1965

The present study is an analysis of some alterations occurring in the population of folliclesin the ovary treated with the gonadotrophins in intact and unilaterally ovariectomized mice. the differences between the findings inthe intact and semispayed animals and those in gonadotrophintreated intact and semispayed animals were disucssed. 1) When mice were semispayed at the stage of diestrus, the remaining ovary showed an increase of secondary follicles in number, while a decrease of atretic folicles, compared with those in intact animals. 2) After injection of PMS and HCG following semispaying at the diestrus stage, the remaining ovary contained larger number of secondary follicles and corpora lutea than those in semispayed animals with no treatment , while showed smaller number of atretic follicles. 3) It is sure that follicular development is remarkably accelerated in the intact mice treated with PMS and HCG. 4) The effect of PMS and HCG on the follicular development was gradually decreased with time in the intact and semispayed animals afte rexogenous hormone therapy. 5) It is believed in the experiment that a decrease of follicular atresia in number and an increase of secondary follicles may be responsible for compensatory reaction after semispaying.

• 한국주조공학회지
• /
• 제30권5호
• /
• pp.161-166
• /
• 2010

In this examination, the effect of Sr addition and holding time on microstructure of Al-10.5wt%Si-2wt%Cu secondary die-casting alloy was investigated. Degree of undercooling was improved with increasing the Sr content in this alloy. Up to 0.02wt%Sr addition, acicular and lamellar eutectic structure was observed in the microstructure. Meanwhile, the eutectic Si was modified toward the fine fibrous form by increasing Sr content with more than 0.03wt% and holding time of the melt. The well- modified alloys showed decreased eutectic silicon size from 3.25 ${\mu}m$ to less than 0.8 ${\mu}m$. From these results, the optimal strontium content and holding time were identified on the Al-10.5wt%Si-2wt%Cu secondary die-casting alloy.