• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.16 no.6
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• pp.241-248
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• 2021

Firms have many ways to expand their businesses including M&A. Big companies in online and offline businesses show different ways of expansion with different objectives to expand their digital businesses quickly. Expansions for technical reasons are to acquire technologies they do not have while those for business reasons are M&A for offline companies to have competence in markets by acquiring online companies. Other ways of expansions include spin-off and group participation after investments for startups. Various ways of expansions are chosen because they are optimal choices depending on situations the companies face, and they have different strengths and weaknesses. To analyze the strengths and weaknesses of those options for expansion at this stage would be academically valuable, and also practically meaningful in terms of providing insights for companies' decision making in choosing opitions for expansions. M&A of online companies to make multi-channels by offline companies have risks of failing to internalize online companies and have enough synergy effects. Also, spin-off is a relatively less risky way of expansion while the speed of expansion is slower than establishing external startups with some shares of equity and making them as affiliated companies. External startups are good for speed of expansion while there are risks of legal regulations and negative awareness by the public.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.66-68
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• 2011

Chollian is a geostationary satellite, and its bipropellant propulsion system is mainly composed of one main engine for orbit transfer and fourteen thrusters for on-station operations. The Chollian was launched successfully at Kourou Space Center in French Guiana. After it separated from the launcher, the propulsion system was initialised automatically. Then three times of main engine firing were successfully performed, and the target obit insertion was accomplished. This paper details the major CPS events during LEOP phase for the Chollian satellite.

• Koreanishche Zeitschrift fur Deutsche Sprachwissenschaft
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• v.6
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• pp.79-98
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• 2002

지금까지 우리는 한국어와 독일어를 비교하면서 동사의 정형과 부정형을 관찰해 왔다. 이 부정성(역으로 말하면 비구속성)은 한국어 동사에는 전반적으로 통용되는 데 반해 독일어에는 부정형/동사원형과 분사가 그러할 뿐이다. 동사의 특성 연구는 어느 자연어/개별언어의 상이한 기능을 위해서 뿐만이 아니라 외국어 학습/습득을 위해서도 큰 의미를 갖는다. 이러한 중요성에도 불구하고 독특한 한국어 동사의 부정성, 그 연구는 거의 찾아볼 수가 없다. 한국어와 독일어 동사의 부정성 비교에서 드러난 문제점은 대체로 다음과 같이 요약될 수 있을 것이다. $\ast$ 한국어 동사의 특징인 부정성은 우리의 운명으로 간주해야 할 것이다. 왜냐하면 우리가 어떤 면에서는 유익함을, 그리고 어떤 다른 면에서는 문제점을 감수해야 하기 때문이다. 특히 전형적인 전치성 언어인 유럽언어를 습득할 때 언어간섭현상을 통해 그러하다. $\ast$ 독일어의 부정사/분사 및 한국어 동사가 인칭변화를 하지 않는다는 것은 그들이 주어를 갖지 않고 있거나 (독일어의 경우), 아니면 그것이 어떤 문법/통사적 역할을 하는가 (한국어의 경우)에 주된 원인이 있다. $\ast$ 비교 대상의 양쪽은 생략가능성, 즉 원자가 요구에 대한 자유/비구속성을 누린다. 핵(성분), 즉 독일어의 부정형 및 분사 그리고 한국어 동사는 혼자 남을 때까지 생략이 계속될 수 있다. 이러한 의미에서 부정성은 <비한정성/비구속성>과 관련된 것 같으며, 반면에 정동사의 특성은 <한정성/구속성>과 관계되어 있다. $\ast$ 원자가 요구/충족에 대한 자유/비구속성은 한국어 동사/술어가 문장 끝에 고정되어 있다는 사실은, 직접 또는 간접으로 본동사 앞에 놓여 있어야 되는 모든 문장성분과 부문장 때문에, 즉 한국어의 전면적인 전위수식 현상으로 흔히 큰 부담/복잡함을 야기한다는 데에 그 원인이 있다. 이러한 상황에서 동사는 가능한 한 그의 문장성분을 줄이려 한다. 통사적으로 보장되어 이미 있으니 말이다. 그래서 한국어 동사의 부정성은 일종의 부담해소 대책으로 간주될 수 있을 것이다. $\ast$ 두 비교 대상에서의 핵 및 최소문장 가능성은 역시 원자가에 대한 비구속성에서 비롯된다. $\ast$ 우리 한국인이 빨리 말할 때 흔히 범하는 부정성으로 인한 인칭변화에서의 오류는 무엇보다도 정형성/제한성을 지닌 독일어 정동사가 인칭 변화하는 데 반해 한국어에서는 부정성/비구속성을 지닌 동사가 그것과는 무관한 페 기인한다. 동사의 속성을 철저히 분석함으로써 이런 과오를 극복해야 할 것이다. 한국어 동사의 부정성은 지금까지 거의 연구되지 않았다. 이 문제는 또한 지속적으로 수많은 다른 자연어들과의 비교분석을 통해 관찰돼야 할 것이다. 이 논문이 이런 연구와 언어습득을 위한 작업에 도움이 되기를 바란다.

• Korean Journal of Materials Research
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• v.25 no.5
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• pp.226-232
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• 2015

High temperature plasma coating technology has been applied to recover damaged aluminum dies from wear by spraying pure aluminum and alumina powder. However, the coated mixed powder layer composed of aluminum and alumina often undergoes a detachment from the substrate, making the coated substrate die unable to maintain its expected life span. In this study, in order to increase the bonding strength between the substrate and the coating layer, a pure aluminum layer was applied as an intermediate bond layer. In order to prepare the specimen with variable bond coating conditions, the bond coat layers with a various gun speed from 10 cm/sec to 30 cm/sec were prepared with coating cycle variations ranging from three to nine cycles. The specimen with a bond coat layer coated with a gun speed of 20 cm/sec and three coating cycles exhibited ~13MPa of adhesion strength, while the specimen without a bond coat layer showed ~6 MPa of adhesion strength. The adhesion strength with a variation of bond coat layer thickness is discussed in terms of coating parameters.

• Journal of IKEEE
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• v.28 no.1
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• pp.97-103
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• 2024

Some drugs can offer far better medical effectiveness as it is injected through the intradermal layer of the skin, known as a needle-free injection. However, conventional needle-free devices might deliver a relatively large amount of drug in a just single spot of skin, splitting open the tissue layer structure, which might cause bruising and bleeding. By injecting the small volume with a fast repetition rate in a large surface area of skin, the patient may get much fewer injuries and pain. To achieve that specification, the driving force must be instantaneous and short-pulsed. Such a form of an injection device has been developed but the efficacy of those devices has been rarely examined. Therefore, this study developed the laser-induced microjet device that ejects microjet whose speed is ~310 m/s, during the 400~800 ㎲ of pulse time. The device can eject ~1 µL of the drug at the rate at which each shot repeated 10 shots per second. Using this specification, we evaluated the efficacy of drug injection onto mouse models. After injecting the insulin solution into the mouse model, the blood insulin level is detected, resulting in 20 % of blood insulin level with the ordinary needle syringe injection method.

• The korean journal of orthodontics
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• v.38 no.5
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• pp.328-336
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• 2008

Objective: The purpose of this study was to compare the torque resistance to removal of sandblasted large grit and acid etched (SLA) surface treated orthodontic mini-implants and smooth surface orthodontic mini-implants as well as performing histologic observations. Methods: Two groups of custom screw shaped orthodontic mini-implants (C-implant, 1.8 mm outer diameter $\times$ 9.5 mm length, Cimplant, Seoul, Korea) were designated. 22 SLA treated C-implants (SLA group) and 22 machined surface C-implants (machined group) were placed in the tibia metaphysis of 11 adult New Zealand white rabbits. Following a 6-week healing period, the rabbits were sacrificed. Subsequently, the C-implants were removed under reverse torque rotation with a digital torque measuring device and independent t-test was performed. Selected tissues were prepared for histologic observation. Results: The SLA group presented a higher mean removal torque value (6.286 Ncm) than the machined group (4.491 Ncm) which was statistically significant (p < 0.005). Histologic observation revealed a trend of more new bone formation in contact with the screw surface in the SLA group than the smooth group. Conclusions: The results of this study suggested that SLA surface treatment can enhance the osseintegration potential for C-orthodontic mini-implants.

• Journal of Dental Rehabilitation and Applied Science
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• v.25 no.4
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• pp.361-374
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• 2009

For successful osteogenesis around the implants, interaction between implant surface and surrounding tissue is important. Biomechanical bonding and biochemical bonding are considered to influence the response of adherent cells. But the focus has shifted surface chemistry. The purpose of this study is to evaluate the MC3T3-E1 osteoblast like cell responses of magnesium (Mg) ion implanted titanium surface produced using a plasma source ion implantation method. Commercially pure titanium disc was used as substrates. The discs were prepared to produce four different surface, A: Machine turned surface, B: Mg implanted surface, C: sandblasted surface, D: sandblasted and Mg implanted surface. MC3T3 El osteoblastic like cells were cultured on the disc specimens. Cell adhesion, proliferation, differentiation, and synthesis of extracellular matrix were evaluated. The cell adhesion morphology was evaluated by SEM. RT PCR assay was used for assessment of cell adhesion, proliferation and differentiation. ALP activity was measured for cell differentiation. The results of this study were as follows: 1. SEM showed that cell on Mg ion groups was more proliferative than that of non Mg ion groups. On the machine turned surface, cell showed some degree of contact guidance in aligning with the machining grooves. 2. In RT PCR analysis, osteonectin and c-fos mRNA were more expressed on sandblasted and Mg ion implanted group. 3. ALP activity was not significantly different among all groups. Within the limitations of this study, the following conclusions were drawn: It might indicate Mg ion implanted titanium surface induce better bone response than non Mg ion groups.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.4
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• pp.235-242
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• 2005

This study is on the evaluation of performance of polymer cement mortar which is used for pre-wetting spray method. Pre-wetting spray method is an epoch-making method to repair concrete structures damaged, which is added a small quantity water preciously to dry mortar to reduce dust and rebound and spray mortar mixed with fixed quantity water at nozzle before spray. The result showed that physical performance such like compressive, flexural and adhesive strength of polymer cement mortar, TS 100 used for pre-wetting spray method was superior to other repair mortar. Also durable performance such as resistance on permeability of chloride ion, carbonation, chemical and freezing-thawing was excellent.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.356-358
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• 2003

The use of cultured epidermal sheet grafts for large full-thickness wound has been tempered by weak points such as long culture periods, difficulty in handling the fragile sheets, high costs and the detachment of the skin cells from the culture dishes by enzymatic digestion. To overcome the drawback of epidermal sheet grafts, we have developed a transplantation method to spray the cultured human keratinocytes with the mixtures of rhEGF and fibrin gel matrix to the full-thickness wounds on the dorsum of the athymic mice to regenerate epithelial layers. Wound biopsies were retrieved at 7, 14 and 21 days after transplantation and retrieved biopsies were analyzed by histology and immunohistochemistry. Transplanted keratinocytes and EGF-fibriin gel accelerated wound regeneration compared with control groups. The technique developed in this study overcomes the drawbacks of the current cultured epidermal sheet grafts and accelerates epidermal wound healing.

• Fire Science and Engineering
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• v.26 no.2
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• pp.53-58
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• 2012

In this study fire control characteristics for inflammable materials of water curtain system are experimentally analyzed. Heat release rate for pinewood and gasoline was calculated using Room Corner Tester (RCT) and fire test apparatus for water curtain system is manufactured. Nozzles (180 degree of injection angle, 8.2 mm of orifice diameter) are installed at the nearby ceiling of place at 5 m distance from fire originate and temperature profile as well as transmission are obtained from the fire experiment of pinewood and gasoline in the water curtain system. Based on the results, parameters of engineering importance for fire control characteristics of water curtain system such as generation of high temperature smoke and thermal phenomena of fluid flow by injection nozzle are identified.