• Title/Summary/Keyword: 2-D model

Search Result 8,578, Processing Time 0.042 seconds

Effect of Package Size and Pasteurization Temperature on the Quality of Sous Vide Processed Spinach (Sous Vide 가공 시금치의 품질에 미치는 포장단위 및 살균온도의 영향)

  • 장재덕;김기태;이동선
    • Food Science and Preservation
    • /
    • v.11 no.2
    • /
    • pp.195-200
    • /
    • 2004
  • Microbial lethal value and nutrient retention of sous vide processed spinach were evaluated with mathematical model prediction and experimental trial for different package sizes and pasteurization temperatures. The package size covers 500 g, 1 kg and 2 kg, while the pasteurization temperature includes 80, 90 and 97$^{\circ}C$. The basic process scheme consists of filling blanched spinach into barrier plastic film pouch, sealing under vacuum, pasteurization in hot water with over pressure and final cooling to 3$^{\circ}C$. Pasteurization condition was designed based on attainment of 6 decimal inactivation of Listeria monocytogenes at geometric center of the pouch package by heating cycle, which was determined by general method. Heat penetration property of the package and thermal destruction kinetics were combined to estimate the retention of ascorbic acid and chlorophyll. Smaller packages with shorter pasteurization time gave better nutrient retention, physical and chemical qualities. Larger package size was estimated and confirmed experimentally to give higher pasteurization value at center, lower ascorbic acid and chlorophyll contents caused by longer heat process time. Lower pasteurization temperature with longer process time was predicted to give lower pasteurization value at center and lower ascorbic acid, while chlorophyll content was affected little by the temperature. Experimental trial showed better retention of ascorbic acid and chlorophyll for smaller package and higher pasteurization temperature with shorter heating time. The beneficial effect of smaller package and higher pasteurization temperature was also observed in texture, color retention and drip production.

Geophysical Study on the Geoelectrical Structure of the Hwasan Caldera in the Euisung Sub-basin Using Magnetotelluric Survey (자기지전류 탐사를 이용한 의성소분지 화산 칼데라의 지구물리학적 연구)

  • Yang, Jun-Mo;Kwon, Byung-Doo;Cho, In-Ky;Lee, Heui-Soon;Park, Gye-Soon;Um, Joo-Young
    • Geophysics and Geophysical Exploration
    • /
    • v.11 no.2
    • /
    • pp.99-108
    • /
    • 2008
  • To extend our detailed knowledge for the Hwasan caldera, we carried out magnetotelluric (MT) survey, which is pretty sensitive to electrical property variation in both horizontal and vertical direction of subsurface, across the Hwasan caldera with the direction of EW. The 2-D inversion results of observed MT data lead to following conclusions. Firstly, the depth of the basin basement inferred by the MT inversion results matches well with that suggested by previous potential studies, but the basement resistivity seems fairly low when compared to that of general case. This feature might be related with the large-scaled, highly conductive layer beneath the Euisung Sub-basin suggested by the previous MT study. Secondly, the high resistivity zones reaching to 4000 $\Omega{\cdot}m$ are imaged around two external ring fault boundaries. These zones are thought of as the response of the rhyolitic dykes intruding along the ring fault, and in the previous gravity data correspond to relatively high density anomalies. Thirdly, low resistivity zone reaching to 200 $\Omega{\cdot}m$ is detected around a depth of 1km beneath the central part of the caldera, which has not been yet reported in korean geophysical literatures. If we take account of the evolution model of the Hwasan caldera, this zone is regarded as the past sedimentary layer that subsided during the period of forming external ring fault system. In addition, the relatively low density anomaly observed in the central part of the caldera may be attributed to this sedimentary layer.

Availability Assessment of Single Frequency Multi-GNSS Real Time Positioning with the RTCM-State Space Representation Parameters (RTCM-SSR 보정요소 기반 1주파 Multi-GNSS 실시간 측위의 효용성 평가)

  • Lee, Yong-Chang;Oh, Seong-Jong
    • Journal of Cadastre & Land InformatiX
    • /
    • v.50 no.1
    • /
    • pp.107-123
    • /
    • 2020
  • With stabilization of the recent multi-GNSS infrastructure, and as multi-GNSS has been proven to be effective in improving the accuracy of the positioning performance in various industrial sectors. In this study, in view that SF(Single frequency) GNSS receivers are widely used due to the low costs, evaluate effectiveness of SF Real Time Point Positioning(SF-RT-PP) based on four multi-GNSS surveying methods with RTCM-SSR correction streams in static and kinematic modes, and also derive response challenges. Results of applying SSR correction streams, CNES presented good results compared to other SSR streams in 2D coordinate. Looking at the results of the SF-RT-PP surveying using SF signals from multi-GNSS, were able to identify the common cause of large deviations in the altitude components, as well as confirm the importance of signal bias correction according to combinations of different types of satellite signals and ionospheric delay compensation algorithm using undifferenced and uncombined observations. In addition, confirmed that the improvement of the infrastructure of Multi-GNSS allows SF-RT-SPP surveying with only one of the four GNSS satellites. In particular, in the case of code-based SF-RT-SPP measurements using SF signals from GPS satellites only, the difference in the application effect between broadcast ephemeris and SSR correction for satellite orbits/clocks was small, but in the case of ionospheric delay compensation, the use of SBAS correction information provided more than twice the accuracy compared to result of the Klobuchar model. With GPS and GLONASS, both the BDS and GALILEO constellations will be fully deployed in the end of 2020, and the greater benefits from the multi-GNSS integration can be expected. Specially, If RT-ionospheric correction services reflecting regional characteristics and SSR correction information reflecting atmospheric characteristics are carried out in real-time, expected that the utilization of SF-RT-PPP survey technology by multi-GNSS and various demands will be created in various industrial sectors.

Geochemistry of Geothermal Waters in Korea: Environmental Isotope and Hydrochemical Characteristics II. Jungwon and Munkyeong Areas (한반도 지열수의 지화학적 연구: 환경동위원소 및 수문화학적 특성 II. 중원 및 문경 지역)

  • Yun, Seong-Taek;Koh, Yong-Kwon;Choi, Hyen-Su;Youm, Seung-Jun;So, Chil-Sup
    • Economic and Environmental Geology
    • /
    • v.31 no.3
    • /
    • pp.201-213
    • /
    • 1998
  • From the Jungwon and Munkyeong areas which are among the famous producers of the carbonate-type groundwaters in Korea, various kinds of natural waters (deep groundwater, shallow groundwater and surface water) were collected between 1996 and 1997 and were studied for hydrogeochemical and environmental isotope (${\delta}^{34}S_{so4}$, ${\delta}^{18}O$, ${\delta}D$)systematics. Two types of deep groundwaters (carbonate type and alkali type) occur together in the two areas, and each shows distinct hydrogeochemical and environmental isotope characteristics. The carbonate type waters show the hydrochemical feature of the 'calcium(-sodium)-bicarbonate(-sulfate) type', whereas the alkali type water of the 'sodium-bicarbonate type'. The former type waters are characterized by lower pH, higher Eh, and higher amounts of dissolved ions (especialJy, $Ca^{2+}$, $Na^{+}$, $Mg^{2+}$, $HCO_3{^-}$ and $SO_4{^{2-}}$). Two types of deep groundwaters are all saturated or supersaturated with respect to calcite. Two types of deep groundwaters were both derived from pre-thermonuclear (about more than 40 years old) meteoric waters (with lighter 0 and H isotope data than younger waters, i.e., shallow cold groundwaters and surface waters) which evolved through prolonged water-rock interaction. Based on the geologic setting, water chemistry, and environmental isotope data, however, each of these two different types of deep groundwaters represents distinct hydrologic and hydrogeochemical evolution at depths. The carbonate type groundwaters were formed through mixing with acidic waters that were derived from dissolution of pyrites in hydrothermal vein ores (for the Jungwon area water) or in anthracite coal beds (for the Munkyeong area water). If the deeply percolating meteoric waters did not meet pyrites during the circulation, only the alkali type groundwaters would form. This hydrologic and hydrogeochemical model may be successfully applied to the other carbonate type groundwaters in Korea.

  • PDF

Presence of Leukemia-maintaining Cells in Differentiation-resistant Fraction of K562 Chronic Myelogenous Leukemia (만성 골수성 백혈병 K562세포의 분화 내성 분획에서 백혈병 유지 세포의 동정)

  • Lee, Hong-Rae;Kim, Mi-Ju;Ha, Gahee;Kim, So-Jung;Kim, Sun-Hee;Kang, Chi-Dug
    • Journal of Life Science
    • /
    • v.23 no.2
    • /
    • pp.197-206
    • /
    • 2013
  • The present study investigated whether leukemia-maintaining cells reside in a differentiation-resistant fraction using a megakaryocytic differentiation model of K562 cells. Treatment with phorbol-12-myristate-13-acetate (PMA) significantly inhibited the colony-forming efficiency of the K562 cells. At a PMA concentration of 1 nM or higher, colony was not formed, but approximately 40% of K562 cells still survived in soft agar. Approximately 70% of colony-forming cells that were isolated following the removal of PMA after exposure to the agent were differentiated after treatment with 10 nM PMA for 3 days. The differentiation rate of the colony-forming cells was gradually increased and reached about 90% 6 weeks after colony isolation, which was comparable to the level of a PMA-treated K562 control. Meanwhile, imatinib-resistant variants from the K562 cells, including K562/R1, K562/R2, and K562/R3 cells, did not show any colony-forming activity, and most imatinib-resistant variants were CD44 positive. After 4 months of culture in drug-free medium, the surface level of CD44 was decreased in comparison with primary imatinib-resistant variants, and a few colonies were formed from K562/R3 cells. In these cells, Bcr-Abl, which was lost in the imatinib-resistant variants, was re-expressed, and the original phenotypes of the K562 cells were partially recovered. These results suggest that leukemia-maintaining cells might reside in a differentiation-resistant population. Differentiation therapy to eliminate leukemia-maintaining cells could be a successful treatment for leukemia if the leukemia-maintaining cells were exposed to a differentiation inducer for a long time and at a high dose.

Application of Environmental Friendly Bio-adsorbent based on a Plant Root for Copper Recovery Compared to the Synthetic Resin (구리 회수를 위한 식물뿌리 기반 친환경 바이오 흡착제의 적용 - 합성수지와의 비교)

  • Bawkar, Shilpa K.;Jha, Manis K.;Choubey, Pankaj K.;Parween, Rukshana;Panda, Rekha;Singh, Pramod K.;Lee, Jae-chun
    • Resources Recycling
    • /
    • v.31 no.4
    • /
    • pp.56-65
    • /
    • 2022
  • Copper is one of the non-ferrous metals used in the electrical/electronic manufacturing industries due to its superior properties particularly the high conductivity and less resistivity. The effluent generated from the surface finishing process of these industries contains higher copper content which gets discharged in to water bodies directly or indirectly. This causes severe environmental pollution and also results in loss of an important valuable metal. To overcome this issue, continuous R & D activities are going on across the globe in adsorption area with the purpose of finding an efficient, low cost and ecofriendly adsorbent. In view of the above, present investigation was made to compare the performance of a plant root (Datura root powder) as a bio-adsorbent to that of the synthetic one (Tulsion T-42) for copper adsorption from such effluent. Experiments were carried out in batch studies to optimize parameters such as adsorbent dose, contact time, pH, feed concentration, etc. Results of the batch experiments indicate that 0.2 g of Datura root powder and 0.1 g of Tulsion T-42 showed 95% copper adsorption from an initial feed/solution of 100 ppm Cu at pH 4 in contact time of 15 and 30 min, respectively. Adsorption data for both the adsorbents were fitted well to the Freundlich isotherm. Experimental results were also validated with the kinetic model, which showed that the adsorption of copper followed pseudo-second order rate expression for the both adsorbents. Overall result demonstrates that the bio-adsorbent tested has a potential applicability for metal recovery from the waste solutions/effluents of metal finishing units. In view of the requirements of commercial viability and minimal environmental damage there from, Datura root powder being an effective material for metal uptake, may prove to be a feasible adsorbent for copper recovery after the necessary scale-up studies.

An Exploratory Study of Hospice Care to Patients with Advanced Cancer (암환자를 위한 호스피스 케어에 관한 탐색적 연구)

  • Park, Hye-Ja
    • The Korean Nurse
    • /
    • v.28 no.3
    • /
    • pp.52-67
    • /
    • 1989
  • True nursing care means total nursing care which includes physical, emotional and spiritual care. The modern nursing care has tendency to focus toward physical care and needs attention toward emotional and spiritual care. The total nursing care is mandatory for patients with terminal cancer and for this purpose, hospice care became emerged. Hospice case originated from the place or shelter for the travellers to Jerusalem in medieval stage. However, the meaning of modem hospice care became changed to total nursing care for dying patients. Modern hospice care has been developed in England, and spreaded to U.S.A. and Canada for the patients with terminal cancer. Nowaday, it became a part of nursing care and the concept of hospice care extended to the palliative care of the cancer patients. Recently, it was introduced to Korea and received attention as model of total nursing care. This study was attempted to assess the efficacy of hospice care. The purpose of this study was to prove a difference in terms of physical, emotional a d spiritual aspect between the group who received hospice care and who didn't receive hospice care. The subject for this study were 113 patients with advanced cancer who were hospitalized in the S different hospitals. 67 patients received hospice care in 4 different hospitals, and 46 patients didn't receive hospice care in another 4 different hospitals. The method of this study was the questionaire which was made through the descriptive study. The descriptive study was made by individual contact with 102 patients cf advanced cancer for 9 months period. The measurement tool for questionaire was made by author through the descriptive study, and included the personal religious orientation obtained from chung(originated R. Fleck) and 5 emotional stages before dying from Kubler Ross. The content ol questionaire consisted in 67 items which included 11 for general characteristics, 10 for related condition with cancer, 13 for wishes far physical therapy, 13 for emotional reactions and 20 for personal religious orientation. Data for this study was collected from Aug. 25 to Oct. 6 by author and 4 other nurse's who received education and training by author for the collection of data. The collected data were ana lysed using descriptive statistics, $X^2-test$, t-test and pearson correlation coefficient. Results of the study were as follows: "H.C Group" means the group of patient with cancer who received hospice care. "Non H.C Group" means the group of patient with cancer who did not receive hospice care. 1. There is a difference between H.C Group and Non H.C Group in term of the number of physical symptoms, subjective degree of pain sensation and pain control, subjective beliefs in physical cure, emotional reaction, help of present emotional and spiritual care from other personal, needs of emotional and spiritual care in future, selection of treatment method by patients and personal religious orientation. 2. The comparison of H.C Group and Non H.C Group 1) There is no difference in wishes for physical therapy between two groups(p=.522). Among Non H.C Group, a group, who didn't receive traditional therapy and herb medicine was higher than a group who received these in degree of belief that the traditional therapy and herb medicine can cure their disease, and this result was higher in comparison to H.C Group(p=.025, p=.050). 2) Non H.C Group was higher than H.C Group in degree of emotional reaction(p=.050). H.C Group was higher than Non H.C Group in denial and acceptant stage among 5 different emotional stages before dying described by Kubler Ross, especially among the patient who had disease more than 13 months(p=.0069, p=.0198). 3) Non H.C Group was higher than H. C Group in demanding more emotional and spiritual care to doctor, nurse, family and pastor(p=. 010). 4) Non H.C Group was higher than H.C Group in demanding more emotional and spiritual care to each individual of doctor, nurse and family (p=.0110, p=.0029, P=. 0053). 5) H.C Group was higher th2.n Non H.C Group in degree of intrinsic behavior orientation and intrinsic belief orientation of personal religious orientation(p=.034, p=.026). 6) In H.C Group and Non H.C Group, the degree of emotional demanding of christians was significantly higher than non christians to doctor, nurse, family and pastor(p=. 000, p=.035). 7) In H.C Group there were significant positive correlations as following; (1) Between the degree of emotional demandings to doctor, nurse, family & pastor and: the degree of intrinsic behavior orientation in personal religious orientation(r=. 5512, p=.000). (2) Between the degree of emotional demandings to doctor, nurse. family & pastor and the degree of intrinsic belief orientation in personal religious orientation(r=.4795, p=.000). (3) Between the degree of intrinsic behavior orientation and the degree of intrinsic: belief orientation in personal religious orientation(r=.8986, p=.000). (4) Between the degree of extrinsic religious orientation and the degree of consensus religious orientation in personal religious orientation (r=. 2640, p=.015). In H.C. Group there were significant negative correlations as following; (1) Between the degree of intrinsic behavior orientation and extrinsic religious orientation in personal religious orientation (r=-.4218, p=.000). (2) Between the degree or intrinsic behavior orientation and consensus religious orientation in personal religious orientation(r=-. 4597, p=.000). (3) Between the degree of intrinsic belief orientations and the degree of extrinsic religious orientation in personal religious orientation(r=-.4388, p=.000). (4) Between the degree of intrinsic belief orientation and the degree of consensus religious orientation in personal religious orientation(r=-. 5424, p=.000). 8) In Non H.C Group there were significant positive correlation as following; (1) Between the degree of emotional demandings to doctor, nurse, family & pastor and the degree of intrinsic behavior orientation in personal religious orientation(r= .3566, p=.007). (2) Between the degree of emotional demandings to doctor, nurse, family & pastor and the degree of intrinsic belief orientation in personal religious orientation(r=.3430, p=.010). (3) Between the degree of intrinsic behavior orientation and the degree of intrinsic belief orientation in personal religious orientation(r=.9723, p=.000). In Non H.C Group there were significant negative correlation as following; (1) Between the degree of emotional demandings to doctor, nurse, family & pastor and the degree of extrinsic religious orientation in personal religious orientation(r= -.2862, p=.027). (2) Between the degree of intrinsic behavior orientation and the degree of extrinsic religious orientation in personal religious orientation(r=-. 5083, p=.000). (3) Between the degree of intrinsic belief orientation and the degree of extrinsic religious orientation in personal religious orientation(r=-. 5013, p=.000). In conclusion above datas suggest that hospice care provide effective total nursing care for the patients with terminal cancer, and hospice care is mandatory in all medical institutions.

  • PDF

A STUDY ON THE IONOSPHERE AND THERMOSPHERE INTERACTION BASED ON NCAR-TIEGCM: DEPENDENCE OF THE INTERPLANETARY MAGNETIC FIELD (IMF) ON THE MOMENTUM FORCING IN THE HIGH-LATITUDE LOWER THERMOSPHERE (NCAR-TIEGCM을 이용한 이온권과 열권의 상호작용 연구: 행성간 자기장(IMF)에 따른 고위도 하부 열권의 운동량 강제에 대한 연구)

  • Kwak, Young-Sil;Richmond, Arthur D.;Ahn, Byung-Ho;Won, Young-In
    • Journal of Astronomy and Space Sciences
    • /
    • v.22 no.2
    • /
    • pp.147-174
    • /
    • 2005
  • To understand the physical processes that control the high-latitude lower thermospheric dynamics, we quantify the forces that are mainly responsible for maintaining the high-latitude lower thermospheric wind system with the aid of the National Center for Atmospheric Research Thermosphere-Ionosphere Electrodynamics General Circulation Model (NCAR-TIEGCM). Momentum forcing is statistically analyzed in magnetic coordinates, and its behavior with respect to the magnitude and orientation of the interplanetary magnetic field (IMF) is further examined. By subtracting the values with zero IMF from those with non-zero IMF, we obtained the difference winds and forces in the high-latitude 1ower thermosphere(<180 km). They show a simple structure over the polar cap and auroral regions for positive($B_y$ > 0.8|$\overline{B}_z$ |) or negative($B_y$ < -0.8|$\overline{B}_z$|) IMF-$\overline{B}_y$ conditions, with maximum values appearing around -80$^{\circ}$ magnetic latitude. Difference winds and difference forces for negative and positive $\overline{B}_y$ have an opposite sign and similar strength each other. For positive($B_z$ > 0.3125|$\overline{B}_y$|) or negative($B_z$ < -0.3125|$\overline{B}_y$|) IMF-$\overline{B}_z$ conditions the difference winds and difference forces are noted to subauroral latitudes. Difference winds and difference forces for negative $\overline{B}_z$ have an opposite sign to positive $\overline{B}_z$ condition. Those for negative $\overline{B}_z$ are stronger than those for positive indicating that negative $\overline{B}_z$ has a stronger effect on the winds and momentum forces than does positive $\overline{B}_z$ At higher altitudes(>125 km) the primary forces that determine the variations of tile neutral winds are the pressure gradient, Coriolis and rotational Pedersen ion drag forces; however, at various locations and times significant contributions can be made by the horizontal advection force. On the other hand, at lower altitudes(108-125 km) the pressure gradient, Coriolis and non-rotational Hall ion drag forces determine the variations of the neutral winds. At lower altitudes(<108 km) it tends to generate a geostrophic motion with the balance between the pressure gradient and Coriolis forces. The northward component of IMF By-dependent average momentum forces act more significantly on the neutral motion except for the ion drag. At lower altitudes(108-425 km) for negative IMF-$\overline{B}_y$ condition the ion drag force tends to generate a warm clockwise circulation with downward vertical motion associated with the adiabatic compress heating in the polar cap region. For positive IMF-$\overline{B}_y$ condition it tends to generate a cold anticlockwise circulation with upward vertical motion associated with the adiabatic expansion cooling in the polar cap region. For negative IMF-$\overline{B}_z$ the ion drag force tends to generate a cold anticlockwise circulation with upward vertical motion in the dawn sector. For positive IMF-$\overline{B}_z$ it tends to generate a warm clockwise circulation with downward vertical motion in the dawn sector.

A Study on the Born Global Venture Corporation's Characteristics and Performance ('본글로벌(born global)전략'을 추구하는 벤처기업의 특성과 성과에 관한 연구)

  • Kim, Hyung-Jun;Jung, Duk-Hwa
    • Journal of Global Scholars of Marketing Science
    • /
    • v.17 no.3
    • /
    • pp.39-59
    • /
    • 2007
  • The international involvement of a firm has been described as a gradual development process "a process in which the enterprise gradually increases its international involvement in many studies. This process evolves in the interplay between the development of knowledge about foreign markets and operations on one hand and increasing commitment of resources to foreign markets on the other." On the basis of Uppsala internationalization model, many studies strengthen strong theoretical and empirical support. According to the predictions of the classic stages theory, the internationalization process of firms have been recognized and characterized gradual evolution to foreign markets, so called stage theory: indirect & direct export, strategic alliance and foreign direct investment. However, termed "international new ventures" (McDougall, Shane, and Oviatt 1994), "born globals" (Knight 1997; Knight and Cavusgil 1996; Madsen and Servais 1997), "instant internationals" (Preece, Miles, and Baetz 1999), or "global startups" (Oviatt and McDougall 1994) have been used and come into spotlight in internationalization study of technology intensity venture companies. Recent researches focused on venture company have suggested the phenomenons of 'born global' firms as a contradiction to the stages theory. Especially the article by Oviatt and McDougall threw the spotlight on international entrepreneurs, on international new ventures, and on their importance in the globalising world economy. Since venture companies have, by definition. lack of economies of scale, lack of resources (financial and knowledge), and aversion to risk taking, they have a difficulty in expanding their market to abroad and pursue internalization gradually and step by step. However many venture companies have pursued 'Born Global Strategy', which is different from process strategy, because corporate's environment has been rapidly changing to globalization. The existing studies investigate that (1) why the ventures enter into overseas market in those early stage, even in infancy, (2) what make the different international strategy among ventures and the born global strategy is better to the infant ventures. However, as for venture's performance(growth and profitability), the existing results do not correspond each other. They also, don't include marketing strategy (differentiation, low price, market breadth and market pioneer) that is important factors in studying of BGV's performance. In this paper I aim to delineate the appearance of international new ventures and the phenomenons of venture companies' internationalization strategy. In order to verify research problems, I develop a resource-based model and marketing strategies for analyzing the effects of the born global venture firms. In this paper, I suggested 3 research problems. First, do the korean venture companies take some advantages in the aspects of corporate's performances (growth, profitability and overall market performances) when they pursue internationalization from inception? Second, do the korean BGV have firm specific assets (foreign experiences, foreign orientation, organizational absorptive capacity)? Third, What are the marketing strategies of korean BGV and is it different from others? Under these problems, I test then (1) whether the BGV that a firm started its internationalization activity almost from inception, has more intangible resources(foreign experience of corporate members, foreign orientation, technological competences and absorptive capacity) than any other venture firms(Non_BGV) and (2) also whether the BGV's marketing strategies-differentiation, low price, market diversification and preemption strategy are different from Non_BGV. Above all, the main purpose of this research is that results achieved by BGV are indeed better than those obtained by Non_BGV firms with respect to firm's growth rate and efficiency. To do this research, I surveyed venture companies located in Seoul and Deajeon in Korea during November to December, 2005. I gather the data from 200 venture companies and then selected 84 samples, which have been founded during 1999${\sim}$2000. To compare BGV's characteristics with those of Non_BGV, I also had to classify BGV by export intensity over 50% among five or six aged venture firms. Many other researches tried to classify BGV and Non_BGV, but there were various criterion as many as researchers studied on this topic. Some of them use time gap, which is time difference of establishment and it's first internationalization experience and others use export intensity, ration of export sales amount divided by total sales amount. Although using a mixed criterion of prior research in my case, I do think this kinds of criterion is subjective and arbitrary rather than objective, so I do mention my research has some critical limitation in the classification of BGV and Non_BGV. The first purpose of research is the test of difference of performance between BGV and Non_BGV. As a result of t-test, the research show that there are statistically efficient difference not only in the growth rate (sales growth rate compared to competitors and 3 years averaged sales growth rate) but also in general market performance of BGV. But in case of profitability performance, the hypothesis that is BGV is more profit (return on investment(ROI) compared to competitors and 3 years averaged ROI) than Non-BGV was not supported. From these results, this paper concludes that BGV grows rapidly and gets a high market performance (in aspect of market share and customer loyalty) but there is no profitability difference between BGV and Non_BGV. The second result is that BGV have more absorptive capacity especially, knowledge competence, and entrepreneur's international experience than Non_BGV. And this paper also found BGV search for product differentiation, exemption strategy and market diversification strategy while Non_BGV search for low price strategy. These results have never been dealt with other existing studies. This research has some limitations. First limitation is concerned about the definition of BGV, as I mentioned above. Conceptually speaking, BGV is defined as company pursue internationalization from inception, but in empirical study, it's very difficult to classify between BGV and Non_BGV. I tried to classify on the basis of time difference and export intensity, this criterions are so subjective and arbitrary that the results are not robust if the criterion were changed. Second limitation is concerned about sample used in this research. I surveyed venture companies just located in Seoul and Daejeon and also use only 84 samples which more or less provoke sample bias problem and generalization of results. I think the more following studies that focus on ventures located in other region, the better to verify the results of this paper.

  • PDF

평행식 진동탄환 암거 천공기의 연구 (IV)(V)-실기 설계 제작 및 보장실험-Development of Balanced-Type Oscillating Mole Drainer(IV)(V)

  • 김용환;이승규;서상용
    • Journal of Biosystems Engineering
    • /
    • v.2 no.1
    • /
    • pp.7-24
    • /
    • 1977
  • This paper is the forth and fifth one of the study on balanced type oscillating mole drainer. In the light of the results from previous reports about the model tests, some design criteria were established and a prototype machine was set up for experimental purpose. Motion characteristics and functionof the each parts of the machine were checked and analyzed. After that, performance tests of the prototype machine were carried out in thefield. Obtained results are summarized as follows ; 1. Ten centimeter of the bullet diameter was determined so as to be able to attach it to the tractors with capacity of 30 PS to 40 PS. 2. To maintain the balance between the moments of the front shank and rear shank, the oscillating amplitude of the rear bullet was determined to be larger than that of the front bullet. At the same time , the oscillating direction of the rear bullet was designed with the inclines of ten to thirty degrees. 3. An octagonal dynamo transduced was developed for measuring the compressive force of the upper link is measuring the draft force of the machine. Acceptable linear relationship between forces and strain responses from O.D.T. was obtained. 4. Analysing the balancing mechanism of the acting part of the machine , it was found that the total draft force of the machine was equal to the difference between the sum of the draft force produced from the right and left side bending moments of the lower drawber and the compressive force on the upper link. 5. There are acceptable linear relationship between the strain and twisting moment by driving shaft, and between strain and shank moment. Above results enable us to carry out the field experiment with prototype machine. 6. When the test machine was used in the field, it was possible to reduce the oscillating acceleration by forty percent in average as compared it with the single bullet mole drainer. 7. When the test machine was used under the oscillating condition, the dratt torce was reduced by 27 percent to 59 percent as compared it with the test machine under non-oscillating condition, while the draft force was increased by 7 percent to 20 percent as compared it with the mole drainer having oscillating single bullet. The reasoning behind this fact was considered as the resistance force due to the rear shank and bullet. 8. As the amplitude and frequency of the bullet were increased, the torque was increased accordingly. This tendency could be varied with the various characteristics of the given soils. And the larger frequency and amplitute, the more increasing oscil\ulcornerlating power but decreasing draft brce were needed, and draft force was increased as the velocity was increased.9. When the amplitude of the rear bullet was designed to be larger than that of the front bullet, the minimum value of the moment was lowered and oscillating acceleration was reduced. And when the oscillating direction of the rear bullet was declined back\ulcornerwards, oscillating acceleration was increased along with the increasing angle of decli\ulcornernation. When the test machine was operated in high speed, the difference between maximum moments and minimum ones became narrow. This varying magnitude of moments appeared on the moment oscillogram seems to be correlated to the oscillating acceleration and draft force. 10. From the analysis of variance, it was found that those factors such as frequency, amplitude, and operating velocity significantly affected in the oscillating acceleration, the draft resistance, the torque, the moment, and the total power required. And interaction between frequency and amplitude affected in the oscillating acceleration. 11. Within the given situation of this study, the most preferable operating conditions of the test machine were 7 Hz in oscillating frequency, 0.54 m/sec in operating velocity, and 39.1 mm in oscillating amplitude of front and rear bullets. However, it is necessary to select the proper frequency and magnitude of oscillation depending on the soil properties of the field in which the mole drainer is practiced by use of a bal1nced type oscillating mole drainer. 12. It is recommended that a comparative study of the mole drainers would be performed in the near future using two separate balanced oscillating bullet with the one which is operated by oscillating the movable bullet in a single cylinder or other balanced type which may be single oscillating bullet with spring, damper or balancing weight, and that of thing. To expand the applicability of the balanced type oscillating mole drainer in practical use, it is suggested to develop a new mechanism which perform mole drain with vinyl pipe or filling material such as rice hull.

  • PDF