• Title/Summary/Keyword: e-System

Search Result 17,262, Processing Time 0.052 seconds

Evaluation of Image Quality for Various Electronic Portal Imaging Devices in Radiation Therapy (방사선치료의 다양한 EPID 영상 질평가)

  • Son, Soon-Yong;Choi, Kwan-Woo;Kim, Jung-Min;Jeong, Hoi-Woun;Kwon, Kyung-Tae;Cho, Jeong-Hee;Lee, Jea-Hee;Jung, Jae-Yong;Kim, Ki-Won;Lee, Young-Ah;Son, Jin-Hyun;Min, Jung-Whan
    • Journal of radiological science and technology
    • /
    • v.38 no.4
    • /
    • pp.451-461
    • /
    • 2015
  • In megavoltage (MV) radiotherapy, delivering the dose to the target volume is important while protecting the surrounding normal tissue. The purpose of this study was to evaluate the modulation transfer function (MTF), the noise power spectrum (NPS), and the detective quantum efficiency (DQE) using an edge block in megavoltage X-ray imaging (MVI). We used an edge block, which consists of tungsten with dimensions of 19 (thickness) ${\times}$ 10 (length) ${\times}$ 1 (width) $cm^3$ and measured the pre-sampling MTF at 6 MV energy. Various radiation therapy (RT) devices such as TrueBeam$^{TM}$ (Varian), BEAMVIEW$^{PLUS}$ (Siemens), iViewGT (Elekta) and Clinac$^{(R)}$iX (Varian) were used. As for MTF results, TrueBeam$^{TM}$(Varian) flattening filter free(FFF) showed the highest values of $0.46mm^{-1}$ and $1.40mm^{-1}$ for MTF 0.5 and 0.1. In NPS, iViewGT (Elekta) showed the lowest noise distribution. In DQE, iViewGT (Elekta) showed the best efficiency at a peak DQE and $1mm^{-1}DQE$ of 0.0026 and 0.00014, respectively. This study could be used not only for traditional QA imaging but also for quantitative MTF, NPS, and DQE measurement for development of an electronic portal imaging device (EPID).

The Effect of Ginkgo Biloba Extract on Radiosensitivity of Mouse Skin and Jejunal Crypt (Ginkgo Biloba Extract가 마우스 피부 및 공장 소낭선의 방사선감수성에 미치는 영향)

  • Shin, Kyung-Hwan;Ha, Sung-Whan
    • Radiation Oncology Journal
    • /
    • v.16 no.2
    • /
    • pp.107-114
    • /
    • 1998
  • Purpose : Ginkgo biloba extract(GBE) is known to increase the peripheral blood circulation. This study was designed to evaluate the effect of GBE on the acute normal tissue radiation reaction. Materials and Methods : mice were divided into two groups, radiation alone and two doses GBE plus radiation, for both acute skin reaction and jejunal crypt assay. GBE was given i.p. one hour before irradiation with priming dose given one day earlier. Thirty to Fifty Gy for acute skin reaction and 11 to 14 Gy for jejunal crypt were irradiated to right hind leg and whole body, respectively. Results : Radiation doses($RD_{50}$) for Peak skin score of 2.0 were 44.2Gy (40.6-48.2Gy) for radiation alone and 44.4Gy(41.6-47.4Gy) for two doses GBE plus radiation, showing no effect of GBE on acute radiation skin damage. The numbers of regenerating jejunal crypts per circumference were also almost the same for each radiation dose level(p=0.57-0.94), and the mean lethal doses($D_o$) were 1.800y(1.57-2.09Gy) for radiation alone and 1.88Gy(1.65-2.18Gy) for two doses GBE plus radiation, indicating no effect of GBE on jejunal crypt cell survival after radiation. Conclusion : GBE doesn't increase acute normal tissue radiation reaction in this model system. As GBE was verified to enhance radiation effect on tumor, high therapeutic gain is expected when GBE is combined with radiation therapy.

  • PDF

Performance Measurements of Positron Emission Tomography: An Investigation Using General Electric $Advance^{TM}$ (양전자방출단층촬영기의 표준 성능평가 방법: GE $Advance^{TM}$에 적용한 예)

  • Lee, J.R.;Choi, Y.;Choe, Y.S.;Lee, K.H.;Kim, S.E.;Shin, S.A.;Kim, B.T.
    • The Korean Journal of Nuclear Medicine
    • /
    • v.30 no.4
    • /
    • pp.548-559
    • /
    • 1996
  • A series of performance measurements of positron emission tomography (PET) were performed following the recommendations of the Computer and Instrumentation Council of the Society of Nuclear Medicine and the National Electrical Manufacturers Association. We investigated the performance of the General Electric $Advance^{TM}$ PET. The measurements include the basic intrinsic tests of spatial resolution, scatter fraction, sensitivity, and count rate losses and randoms. They also include the tests of the accuracy of corrections: count rate linearity correction, uniformity correction, scatter correction and attenuation correction. GE $Advance^{TM}$ PET has bismuth germanate oxide crystals (4.0mm transaxial ${\times}$ 8.1mm axial ${\times}$ 30.0mm radial) in 18 rings, which form 35 imaging planes spaced by 4.25mm. The system has retractable tungsten septa 1mm thick and 12cm long. Transaxial resolution was 4.92mm FWHM in 2D and 5.14mm FWHM in 3D at the center. Average axial resolution in 2D decreased from 3.91mm FWHM at the center to 6.49mm FWHM at R=20cm. Average scatter fraction of direct and cross slices was 9.57%. Dead-time losses of 50% corresponded to a radioactivity concentration of $4.86{\mu}Ci/cc$ and a true count rate of 519 kcps in 2D. The accuracy of count rate linearity correction was 1.84% at the activity of $4.50{\mu}Ci/cc$. Non-uniformity was 2.06% in 2D and 2.93% in 3D. Remnant errors after scatter correction were 0.55% in 2D and 4.12% in 3D. The errors of attenuation correction were 6.21% (air), 0.20% (water), -6.32% (teflon) in 2D and 5.00% (air), 6.94% (water), 3.01% (teflon) in 3D. The results indicate the performance of GE $Advance^{TM}$ PET scanner to be well suited for clinical and research applications.

  • PDF

A Study on the Experience of Physical Therapy Accident in The Physiotherapist (물리치료사에 있어서 물리치료 사고의 경험에 관한 연구)

  • Kim, Jong-Dae
    • Journal of Korean Physical Therapy Science
    • /
    • v.9 no.1
    • /
    • pp.69-80
    • /
    • 2002
  • The objective of research provides the physical therapy of good quality to the patients to search for the problem pant against a physical therapy accident and it simultaneously respects physical therapy company law, the possibility of preparing a system defensive ability in order to be. The data were collected from 2000 October 1 to December 30th, and analyzed by a frequency and a percentage, oneway ANOVA, Scheffe method, $x^2$ official approvals. Conclusion (1) the accident where the patient falls from inside the treatment 'room is many and occasionally' 29.3% (63 people) with was many most. (2) Because of a mistake by a part-time therapist in holiday or a colleague therapist to do, the fracture or bum accident happens 12.5% (27 people), by a assist nurse due to more showed 12.1% (26 people) experience degree in the patient. (3) From physical therapy process breakdown of the medical treatment machinery and tools or it is in malfunction to do and the experience which has a failure to physical therapy is one enemy 68.1% (147 people) was in item. Also it treats and the patient or in the protector it sends an explanation in advance not to be, the experience which it enforces 50% (108 people), of service hour treatment equipment the medical treatment directives broad way of the doctor is accurate in insufficiency and does not enforce the experience is 45.4% (98 people), the patient whom I am treating Hot Pack (electricity has pack inclusion) with to do, the art dealer (over at 1 buffoonery) the experience which it puts on 27.1% (58 people), The patient whom I am treating is the electrotherapy flag (electricity has pack exclusion) with to do, the art dealer (1 degree art dealer over) the experience which it puts on 16.3% (35 people), the experience boat song the patient against a fracture from physical therapy process 9 person (4.2%) was visible an experience degree. (4) With hospital infection to do, from the patient the experience and the therapist which receive a problem proposal were caused by with hospital infection and the answer back regarding the experience which tries to receive a treatment appeared 6% (13 people), 42% (9 people) with each. (5) It listened to the treatment hour patient or the appeal of the protector and especially it does not appear to be being important it was not and and the management which is special it did not take, also the experience where the condition of the patient is deteriorated after that was 10.3% (22 people). (6) The condition or state of the patient does not agree with the medical treatment instruction of the doctor not to be, amendment one experience was 67.5% (145 people). (7) The experience degree of the physical therapy accident which relates with physical therapy recording and a secret maintenance 59.7% (129 people) 'is many and occasionally it is,' it showed an answer back and e it showed a most high accident experience degree. (8) The business overweight of physical therapy company 43.3% (93 people) with was high most from recognition degree of the physical therapy company against a physical therapy accident. (9) Against the question which asks the responsibility subject matter of physical therapy accident the whole answer back volition 42.8% did it is a joint responsibility where the multi person relates. (10) The accident occurs most the hour unit which plentifully in the afternoon 64.3% (133 people) with appeared from the recognition degree against the frequency hour unit of physical therapy accident. (11) Physical therapy it bought and after the various medical treatment accident which relates against the attitude of the, patient side against the physical therapy company it understood and trillion it was many most with 33.3% to be finished. (12) After physical therapy accident the management against the physical therapy company of the hospital authorities concerned above all do not experience 70.6% (149 people), from event right and wrong submission 22.7% (48 people), warning management 2.8% (6 people), the event report requirement and money compensation were each 0.5% (1 person). (13) As the prevention book of physical therapy accident most it is important, the fact which it thinks that, the persons supplement of physical therapy company 58.8% (127 people) with was high most. (14) It related with a physical therapy accident and the medical law 43.5%, civil law 23.9%, was visible the answer back ratio of the criminal law 13.7% from the degree which probably is a relation law.

  • PDF

A Survey on Preliminary Dental Hygienists' Senses of Employment (예비치과위생사의 취업에 관한 의식 조사)

  • Han, Su-Jin;Lee, Sun-Mi;Lim, Mi-Hee
    • Journal of Korean society of Dental Hygiene
    • /
    • v.7 no.4
    • /
    • pp.583-594
    • /
    • 2007
  • The purpose of this study was to conduct a survey on the senses that preliminary dental hygienists have on employment, who applied for the National Dental Hygienist Examination, so that it could provide a basic reference required for fostering good human resources specializing in oral health with a sense of mission and responsibility as professional. To meet these goals, a self-administered questionnaire survey was conducted for participants in a refresher education meeting for preliminary dental hygienists across three major regions(Seoul, Daejeon and Busan), which was held by the Korean Dental Hygienists Association(KDHA) on Jan. 15, 2006. Total 289 sheets of questionnaire were collected, and 262 sheets except invalid or incomplete ones were used for examination and analysis. As a result, this study came to the following conclusions: First, it was found that 40.4% respondents wanted to be employed in dental clinic or hospital. Most respondents(90.1%) answered that faithfulness is most valued as prerequisite qualification for employment in hospital, and highest percentage of respondents(39.3%) wanted to earn 16 to 17 million Korean won annually. For internship opportunities, 61.9% respondents replied that they could willingly accept the internship, provided that basic pay and switchover to regular employee are all assured. Second, as the results of survey on employment circumstances around respondents, it was found that most respondents(58.3%) were employed in dental clinic or hospital, and highest percentage of respondents(35.0%) earned 15 to 16 million Korean won. Third, it was found that interpersonal relationships among employees had most significant effects(4.81) on selection of employment, which was followed by in-house welfare benefits 1(monthly/annual vacation, resting room, etc; 4.56). For possible influential factors on the selection of employment depending on whether employed or not, it was found that there were Significant differences in pay, welfare benefit 2(seminar, orientation, refresher training opportunities, etc), post-wedding continued employment and merit system between employees and non-employees(pE0.05). Fourth, the survey on respondents' occupational senses of dental hygienist showed that major tasks of dental hygienists were represented by oral disease prevention(92.6%), case management(71.5%), oral health education(66.3%), hospital/clinic management and dental management support(10.4%) and public oral health activities(6.7%) respectively. For job satisfaction, it was found that almost half respondents(48.9%) showed satisfaction at their job and 32.6% felt satisfied at and proud of their job. That is, majority of respondents(81.5%) felt satisfied at their job as dental hygienist. For follow-up requirements to qualify for dental hygienists, it was found that 73.3% felt it necessary to give more investments to self-development, 62.2% respondents considered protection of membership's rights as one of future assignments that KDHA should be more committed to. For future social awareness about dental hygienists as occupation, 69.2% respondents expected that they would be better developed and treated as professional. And desired training courses as a part of qualification for professional dental hygienists were represented by case management(services, manners, etc; 33.3%), implant(28.9%), esthetics(correction, prosthesis, whitening; 18.9%) and so on. For an item on working years, it was noted that 75.9% respondents would keep working as dental hygienists as long as they could.

  • PDF

Microbiological Safety Assessment to Secure Safety of Food Service in University (대학 내 급식소의 안전성 확보를 위한 미생물학적 안전성 평가)

  • Kim, Kyeong-Yeol;Nam, Min-Ji;Nam, Bo-Ram;Ryu, Hee-Jung;Heo, Rok-Won;Shim, Won-Bo;Chung, Duck-Hwa
    • Journal of Food Hygiene and Safety
    • /
    • v.25 no.1
    • /
    • pp.49-58
    • /
    • 2010
  • The objectives of this study were to investigate the microbial contamination levels on food service in university and to provide the information of microbial contamination to improve food safety. A total of 288 samples were collected during summer and winter season between 2006 and 2008 from 4 food services located in the university in Western Gyeongnam and were used to detect sanitary indicator bacteria [aerobic plate count (APC), coliform, and Escherichia coli] and pathogenic bacteria (Staphylococcus aureus, Salmonella spp.). As a result, APC and coliform for hand and kitchen utensils which are used often by the employee were detected at high levels of 1.1~5.5 and 1.3~5.3 log CFU/($100\;cm^2$, hand), respectively. The contamination levels of APC and coliform in cooked foods and drinking water were 0.8~6.4 and 1.3~5.0 log CFU/(g, mL), respectively. Especially, the cooked foods showed the highest contamination for APC (2.1~6.4 log CFU/g) and coliform (1.0~5.0 log CFU/g). We think the reason that the cooked foods may be contaminated with APC and coliform on cooking process by using employee's hand and kitchen utensils. Moreover, S. aureus for hand and kitchen utensils was detected at levels of 2.8~3.0 and 2.0~2.3 log CFU/(g, hand), but Salmonella spp. was not detected. According to the above results, contamination levels of the samples were mostly decreased irrespective of summer and winter season. The results obtained indicated that it is necessary to periodic monitoring for microorganism contamination and education about personal and environmental hygiene to employee for ensuring food safety of food service in university.

식품과 알레르기: 유전자 재조합 식품의 알레르기 위험성

  • 손대열
    • Proceedings of the Korean Journal of Food and Nutrition Conference
    • /
    • 2000.12a
    • /
    • pp.29-34
    • /
    • 2000
  • 산업 발달에 따라 날로 많은 식품들이 새롭게 개발되어지고 있다. 또한 이와 병행해서 식품으로 인한 알레르기 발생 빈도도 날로 증가하고 있으며 그 증상 또한 점차 심화되고 있는 것이 세계적인 추세이다. 우리나라도 예외는 아니어서 일반 알레르기 환자뿐 아니라 식품으로 인한 알레르기 환자들이 점차 증가됨이 보고되어지고 있다. 농산물 시장의 수입개방이후 우리나라에는 많은 해외 농산물이 수입되어지고 있으며 그 중 작년 한해의 경우 총 수입 농산물의 10%를 넘는 유전자 재조합 농산물이 우리나라에 수입되어진 것으로 통계 보고되어졌다. 이러한 관점에서 알레르기 환자의 증가와 새로운 식품 (특히 유전자 재조합 식품)의 증가에는 서로 관련성이 있을 것으로 추측되어지고 있어 (새로운) 식품에 대한 알레르기성의 예측과 관리가 필요한 실정이다. 이에 몇몇 발표된 유전자 재조합 식품에 관련된 알레르기성 검사 논문들과 실험실에서 이루어진 연구 결과들을 중심으로 유전자 재조합 식품의 알레르기 위험성에 대해 알아보고자 한다. 일반적으로 식품의 단백질이 알레르겐(allergen)으로 작용하기 위해서는 먼저 소화효소에 의해 분해되어지고 장에서 흡수되어져서 immunopotent cell에 의해 process 되어 immune system에 present 되어져야 한다. 따라서 단백질로 인한 알레르기 반응은 그 단백질의 자연적 형태 뿐만이 아니라 소화 효소에 분해된 단편들의 구조 또는 다른 알레르겐 단백질과의 유사 구조로 인한 교차 반응에 의해 발생함을 기억해야 한다. 식품 단백질 중 어떤 단백질이 알레르겐으로 작용하는가에 대한 특이성 조사에 많은 관심이 집중되어지고 있지만 아직까지는 대략 다섯 개 정도의 일반적인 특성으로서 요약되어질 수 있다. 그러나 이러한 대략의 특성에 적용되지 않는 식품 알레르겐도 많음을 잊어서는 안 될 것이다. 알레르겐으로 작용하는 식품 단백질의 일반적 특성 1. 좋은 수용성 2. 식품내에 많은 부분을 차지하는 주 단백질이 주 알레르겐으로 작용 3. 단백질내에 하나 이상의 IgE-binding site 존재 4. 위장액에 대한 저항성 5. 10~70 kDa 크기 유전자 재조합 기술이란 말 그대로 유전자를 인위적으로 새롭게 조합하는 기술로 이전의 기술로는 불가능했던 유전적 변형을 농작물과 동물에 가능하게 했으며 이로 인해 유전적으로 변형된 식용 동식물의 개발이 가능하게 되었다. 새로운 유전인자를 개체에 삽입함으로 새로운 단백질이 발현 될수 있고 그로 인해 1) 해충과 질병에 대한 저항성 증가, 2) 화학 제초제에 대한 새로운 저항성 부여, 3) 식품의 저장성 향상, 4) 식품의 영향적 보충/향상 등의 이점을 얻을 수 있다 (표 1). 세계적으로 유전자 재조합 된 새로운 농산물의 재배는 날로 증가추세에 있으며 그 중에서 가장 많은 부분을 차지하는 농산물로 soybean을 들 수 있으며 (표 2) soybean을 중심으로 그 알레르기성의 변화가 연구 조사된 몇 가지 예를 살펴보고자 한다. (표 3)에 요약된 soybean중 첫 번째 경우는 재초제에 대한 저항성을 높여주기 위해 Agrobacterium에 존재하는 EPSPS라는 단백질을 콩에서 발현하도록 찬 유전자 재조합 된 콩의 경우이다. 이 콩의 경우에는 첫째. 이전된 새로운 단백질 EPSPS가 다른 여러 식물에 이미 존재하고 있는 단백질로서 우리가 이미 이러한 식품을 섭취할 때 이 단백질도 같이 섭취해오고 있었다는 점, 둘째. 이 단백질이 소화액 분해 실험에서 짧은 시간내에 분해가 되었다는 점, 셋째. 재조합 된 콩과 자연 콩이 성분 분석에서 차이를 나타내지 않았다는 점, 네 번째. 쥐를 통한 다양섭취 실험에서 아무런 이상 반응이 없었다는 점등의 결과를 기준으로 알레르기에 대한 개별 검사 없이 안전한 콩으로 결론짓고 있다. 영양성을 높이기 위해 Brazil nut에서 methionine 함량이 풍부한 2s albumine을 콩에서 발현하도록 한 두 번째 유전자 재조합 콩의 경우 이전된 단백질 때문에 Brazil nut에 알레르기 반응을 일으키는 알레르기 환자들을 조사한 결과 역시 재조합 된 콩에도 알레르기 반응을 일으켰다는 보고이다. Brazil nut에서 콩으로 이전된 단백질이 Brazil nut에서의 알레르기성을 그대로 유지한 점을 볼 때 새로운 단백질이 어디에서 유래하는가가 중요함을 잘 보여준 연구이다 세 번째 콩의 경우 역시 영양성을 높여주기 위해 corn에서 10 kDa과 HSZ 단백질을 콩에서 발현하도록 유전자 재조합했는데 이 콩의 경우는 알레르기 환자들이 유전자 재조합 된 콩과 자연 콩에 반응의 차이를 나타내지 않았다는 결과 보고이다. 위의 세 실험 결과들을 종합해 볼 때 무엇보다도 새롭게 발현된 단백질이 원래 어떤 성질을 갖고 있으며 어디에서 유래했는지가 알레르기성 조사에 중요한 역할을 한다 할 수 있겠다. 또한 유전자 재조합된 식품들은 알레르기 환자들을 위해 표기되어져야 할 것인데 이를 위한 알레르기성 검사 실험은 공공단체를 통해 이루어져야 할 것이며 환자들마다 알레르겐으로 작용하는 단백질의 인식부위(epitope)가 다를 수 있기 때문에 적어도 10명 이상의 알레르기 환자들이 조사되어져서 검사가 이루어져야 할 것이다. 환자들의 혈청을 통한 in vitro 실험에서는 ELISA, RAST, immunoblotting과 같은 검사 방법들이 적용될 수 있고, 그 결과가 음성인 경우에 그 다음 단계로 in vivo 실험에서는 직접 환자의 피부반응검사 (skin prick test)나 DBPCFC (double-blind placebo-controlled food challenge) 검사 방법을 통해 확인되어져서 이 모든 경우가 음성인 경우와 하나라도 양성인 경우를 구별하여 식품에 표기함으로 알레르기 환자들의 유전자 재조합 식품에 대한 안전성이 보장되어져야 할 것이다.

  • PDF

Rainfall and Hydrological Comparative Analysis of Water Quality Variability in Euiam Reservoir, the North-Han River, Korea (북한강 의암호의 수질 변동성에 대한 강우·수문학적 비교분석)

  • Hwang, Soon-Jin;Sim, Yeon Bo;Choi, Bong-Geun;Kim, Keonhee;Park, Chaehong;Seo, Wanbum;Park, Myung-Hwan;Lee, Su-Woong;Shin, Jae-Ki
    • Korean Journal of Ecology and Environment
    • /
    • v.50 no.1
    • /
    • pp.29-45
    • /
    • 2017
  • This study explored spatiotemporal variability of water quality in correspondence with hydro-meteorological factors in the four stations of Euiam Reservoir located in the upstream region of the North-Han River from May 2012 to December 2015. Seasonal effect was apparent in the variation of water temperature, DO, electric conductivity and TSS during the study period. Stratification in the water column was observed in the near dam site every year and vanished between August and October. Increase of nitrogen nutrients was observed when inflowing discharge was low, while phosphorus increase was distinct both during the early season with increase of inflowing discharge and the period of severe draught persistent. Duration persisting high concentration of Chl-a (>$25mg\;m^{-3}$: the eutrophic status criterion, OECD, 1982) was 1~2 months of the whole year in 2014~2015, while it was almost 4 months in 2013. Water quality of Euiam Reservoir appeared to be affected basically by geomorphology and source of pollutants, such as longitudinally linked instream islands and Aggregate Island, inflowing urban stream, and wastewater treatment plant discharge. While inflowing discharge from the dams upstream and outflow pattern causing water level change seem to largely govern the variability of water quality in this particular system. In the process of spatiotemporal water quality change, factors related to climate (e.g. flood, typhoon, abruptly high rainfall, scorching heat of summer), hydrology (amount of flow and water level) might be attributed to water pulse, dilution, backflow, uptake, and sedimentation. This study showed that change of water quality in Euiam Reservoir was very dynamic and suggested that its effect could be delivered to downstream (Cheongpyeong and Paldang Reservoirs) through year-round discharge for hydropower generation.

Geochemical Exploration Technics in the Pungchon Limestone Area (풍촌 석회암지대 탐사에 적용될 새 지화학탐사법 연구)

  • Moon, Kun Joo
    • Economic and Environmental Geology
    • /
    • v.23 no.4
    • /
    • pp.369-381
    • /
    • 1990
  • Most of significant ore deposits in South Korea such as the Sangdong W - Mo, the Yeonhwa Pb-Zn and the Geodo Cu-Fe skarn ore deposits occur at the southern limb of the Hambaeg syncline in the Taebaeg Basin. The mineralization took place in the interbedded limestone of the Myobong Formation and the Pungchon limestone of the Great Limestone Group of the Cambrian age, generally striking E-W and dipping 25-30 degrees north. There are no outcrops of the skarn-type orebody at the northern limb of the syncline. In order to find a clue of a possible hidden orebody localized at the limestones in the northern limb, a lithogeochemical exploration by using carbon isotope and some elements such as Si, Ca, Fe and Al at the Sangdong Mine area has been attempted as for a modelling study. For this study, 45 samples from the Pungchon limestone which do not show any megascopic indication of mineralization have been taken in both the mineralized zone and the unminerallized zone at the Sangdong Mine area. Analytical data show that there are big differences in the contents of CaO and $Al_2O_3$ between the Pungchon limestone of the mineralized zone and that of the unmineralized zone. Carbon isotope data exhibit that ${\delta}^{13}C$ values of the Pungchon limestone in the mineralized zone are highter than those in the unmineralized zone. The difference in the analytical values of CaO, $Al_2O_3$ and the carbon isotope between the mineralized and the unmineralized zones is as follows ; Unminerallized zone Mineralized zone CaO 51.3% 43.5% $Al_2O_3$ 0.6% 2.4% ${\delta}^{13}C$ -0.39 permil -0.56 permil $Fe_2O_3$ 0.9% 1.4% $SiO_2$ 3.0% 2.4% The decrease in the Si content of the Pungchon limestone in the mineralized zone is contrary to the result of the previous study (Moon, 1987). On the basis of identification of the increase in the Al content of the limestone in the mineralized zone, it could be deduced that the decrease in the Si content of the Pungchon limestone might be due to the result of increase in the alteration products mainly occurred along fracture-system such as joint cracks or minor faults and that the phenomena shown by the Si and Al content in the mineralized zone might be derived from the thermal effect of granite extended mineralizing activity to the overlied limestone on the surface. Higher mean values of Fe and Al as well as lower mean values of carbon content and the ${\delta}^{13}C$ than mean values of those in the Pungchon limestone at the northern limb of the Hambaeg Syncline may be applicable in exploration for blind orebodies.

  • PDF

A Study on Balanced -type Oseillating Mole-Drainer(III)-Model Test for Draft Force, Torque, Power and Moment (평행식 진동탄환 암거 천공기의 연구(III)-견인력, 토크, 동력 및 모멘크에 관한 모형시험-)

  • 김용환
    • Journal of Biosystems Engineering
    • /
    • v.1 no.1
    • /
    • pp.1-6
    • /
    • 1976
  • This paper is the third one of the study on balanced type oscillating mole-drainer, the first one was presented in No 9. Gyeongsang College Report and the second one in Vol. 17, No.4 of the KSAE. In the first part of this study, the characteristics of traction forces between the nonoscillating earth working equipments and oscillating ones was compared. A model of the balanced type oscillating mole-drainer, which composed of a mechanism that may reduce the machine vibration, was designed following the dimensional analysis and similitude technique. The model test was carried out to clarify the balancing mechanism of the oscillating parts and other parts of the machine. In the light of the results from the model tests, a prototype machine was made for experimental purpose. Results from the field test by a reported in the near future. In the second report, the model tests were carried out under the same soil conditions, i.e, . oscillating frequency, running velocity, and oscillating amplitude, etc. It was clear that use of balanced type oscillating model could substantially reduce the vibration of the whole system of the machine, when compared with the nonoscillating type model. In this paper(the third report), results of investigation on the traction force, power requirement, and moment. etc, is presented. Analysis of variance technique was used for analyzing the effect of the frequency, amplitude, and running velocity on the draft force, torque, power requirements, and moments. The results obtained from the model tests are as follows, 1) By practicing a balanced-type oscillating mole-drainer, it was possible to reduce the traction resistance by 55.1-61. 2 percent of traction resistance, however, was 1.75 - 1.95 times greater than the value of resistance which was induced by use of a mole-drainer with single bullet. The resistance of rear shank against soil was considered as a main causing factor of the above results. 2) As the oscillation frequency was increased, the traction resistance was decreased. Considering on the effect of oscillation the greater the amplitude, and the slower the running velocity was, the greater the reduction ratio of traction resistance was. 3) The ratio of the traction resistance of oscillating mole-drainer to that of non-oscillating one could be represented as a function of dimensionless variable (V/$Af$). The results from the tests were well agreed with the reported results from the experim ents on oscillation plow or hoe. 4) By taking a lower value of (V/$Af$), reducing the traction resistance was possible. This fact meant, however, that the efficiency of mole drain practice would be lower. 5) It was experimentally confirmed under the same condition of soil that the variable (R/$rD1^3$) could be represented as a function of a variable($V^2/gD$) when a non\ulcornerocillating mole-drainer was used. 6) When a oscillating mole-drainer was used, the variable(R/$rD_1^{3}$) could be represented as a function of two variables ($v^2/gD_1$) and (V^2/gD_1$). 7) The torque was not affected by a change of frequency. However, a relation of proportionality existed between torque and amplitude, running velocity, and ratio of bullet diameter. When a balanced type oscillating mole-drainer with two bullets was used, torque was increased by 52.8-78. 4 percent and total power requirement was also increased. 8) Total power requirement was increased linearly in accordance with the increasing frequency, 41.96 percent of total power was used for oscillating action. The magnitude of total power requirement was 1. 8-9. 4 times greater than that of a non-oscillating mechanism. In the view point of power requirement, it was not advisable to increase the frequency, amplitude, running velocity, and ratio of bullet diameter at the same time. 9) Only the positive moment occured in the rear shank. Change of the diameter of a rear bullet, could not affect the balancing against the soil resistance. It was necessary for rear bullet to have a large resistance against soil only when the rear bullet was in backward motion. 10) Within an extent of the experimental base, optimum limits for several design factors were A=0.5cm, $f$=22.5Hz, V=O. 05m/sec, and $\lambda$=1.0 By adapting these values traction resistance was reduced by 40 percent and vibration acceleration wa s reduced by 60 percent. Even though the total , power requirements for operating a balanced type oscillation mechanism was greater ~than that of non-oscillating one, using a oscillating mechanism would be more effective. Because a balanced type oscillating mechanism is used, tractive resistance will be reduced and then the lighter . tractive equipment could be used.

  • PDF