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구강 세균 채취법에 따른 세균의 다양성과 양 분석을 위한 예비 연구 (Preliminary study on the diversity and quantity analysis of oral bacteria according to the sampling methods)

  • 심선주;김지혜;신혜선
    • 한국치위생학회지
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    • 제24권2호
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    • pp.131-139
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    • 2024
  • Objectives: Oral bacterial samples included subgingival, supragingival, and saliva plaques. As the diversity and number of microorganisms deffer depending on the area of the oral cavity and the method used, an appropriate and reliable collection method is important. The present study investigated oral bacterial sampling methods. Methods: Supragingival dental plaque was collected from the buccal and lingual tooth surfaces of study participants using sterilized cotton swabs. Plaques were collected from the subgingival area using a sterilized curette. Bacterial genomic DNA was extracted using MagNA Pure 96 DNA and Viral NA low-volume kits. Real-time polymerase chain reaction (PCR) was performed using the PowerCheckTM Periodontitis Pathogens Multiplex Real-time PCR kit. Results: Aggregatibacter actinomycetemcomitans, Prevotella intermedia, and Fusobacterium nucleatum of the orange complex were not observed in the subgingival biofilms of all study participants. For Porphyromonas. gingivalis, a significant correlation was observed between supragingival, subgingival, and total tooth surface biofilms. Compared to the supragingival and subgingival biofilmss, total tooth surface biofilm exhibited the highest bacterial count when the inswabbing method was used. Conclusions: Based on these findings, the supragingival swab method is recommended for oral bacterial research.

이온빔 보조 전자빔 수산화 인회석 증착이 골내 임플란트의 골유착에 미치는 영향 (EFFECTS OF THE ION BEAM ASSISTED DEPOSITION OF HYDROXYAPATITE ON OSSEOINTEGRATION OF THE ENDOSSEOUS IMPLANTS IN RABBIT TIBIAE)

  • 정영철;한종현;이인섭;이현정;김명호
    • 대한치과보철학회지
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    • 제38권5호
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    • pp.659-674
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    • 2000
  • A large increase in the use of thin film coating of hydroxyapatite(HA) in implant dentistry is driven by the desire to take advantage of the excellent biocompatibility and high strength of HA coating. The purpose of this study was to evaluate the effects of HA-coated implants by ion Beam Assisted Deposition(IBAD) method in comparison to the sand-blasted and machined surfaces. Osteoblast culture test, removal torque test and histomorphometric analysis were performed and the following results obtained; 1. Examination of the osteoblast cultures displayed no difference in the secretion of alkaline phosphatase between the various specimen, but IBAD with pure HA specimen showed low alkaline phosphatase secretion(p<0.05). 2. Removal torque tests showed HA-coated implants by IBAD method to be similar in high value to the implants with sand-blasted surface than the implants with machined surface. And the ovariectomized group showed low mechanical test value than the normal group(p<0.05). 3. Histomorphometrical comparisons were performed on undecalcified ground sections. HA-coated implants by IBAD method demonstrated the highest mean bone-to-metal contact ratio on all threads and 3-best consecutive threads, and the implants with sand-blasted surface and implants with machined surface was in the next consecutive order(p<0.05). HA-coated implants showed slightly higher bone-to- metal contact ratio than sand-blasted implants, but no statistically significant difference was obtained between the two materials. The ovariectomized group showed lower value of bone-to-metal contact ratio than the normal group, but no statistically significant difference was obtained between the two groups. 4. Evaluation of bone volume on all threads and 3-best consecutive threads showed no statistically significant difference among the different surface treatment groups, but showed lower bone volume in ovariectomized group than in the normal group(p<0.05). According tn these results, thin film coated implants with HA showed high bone contact ratio, bone volume and removal torque strength in the short term, but long term observation is needed.

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승모판 협착증 환자에서 운동부하 심장풀스캔을 이용한 좌심실기능의 평가 (Exercise Radionuclide Ventriculography in Patients with Mitral Stenosis)

  • 이도연;심원흠;김한수;박승정;조승연;김성순;이웅구;김명진;최규옥;박창윤
    • 대한핵의학회지
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    • 제26권1호
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    • pp.58-64
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    • 1992
  • We performed exercise radionuclide ventriculography to evaluate left ventricular (LV) function in 35 patients with pure mitral stenosis (MS). There were 6 males and 29 females ranging from 21 to 63 years of age (mean $37{\pm}10$ years). We also studied 8 healthy men as control group (mean age $27{\pm}5$ years). Each patients was evaluated at rest and during maximal exercise on an isokinetic bicycle ergometer. Peak filling rate (PFR), peak ejection rate (PER), ejection fracion (EF), end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), and cardiac output (CO) were determined by the radionuclide technique. The results were summarized as follows: 1) LV systolic dysfunction and reduced PFR were noted in patients with MS. 2) EDV as well as SV decreased with exercise in patients with MS. 3) No significant increase in EF during exercise compared to rest value was observed because it was caused by reduced EDV and SV during exercise in patients with MS. 4) CO increased with exercise was significantly lower than normal in patients with MS. 5) Patients with MS were divided into two groups according to whether SF increased more than 5% druing exercise compared to resting state or decreased. Significant difference were found between these two groups. Patients with a fall in EF with exercise were older, had larger left atrial size, and had lesser decreased in ESV during exercise.

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Breast Radiotherapy with Mixed Energy Photons; a Model for Optimal Beam Weighting

  • Birgani, Mohammadjavad Tahmasebi;Fatahiasl, Jafar;Hosseini, Seyed Mohammad;Bagheri, Ali;Behrooz, Mohammad Ali;Zabiehzadeh, Mansour;meskani, Reza;Gomari, Maryam Talaei
    • Asian Pacific Journal of Cancer Prevention
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    • 제16권17호
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    • pp.7785-7788
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    • 2015
  • Utilization of high energy photons (>10MV) with an optimal weight using a mixed energy technique is a practical way to generate a homogenous dose distribution while maintaining adequate target coverage in intact breast radiotherapy. This study represents a model for estimation of this optimal weight for day to day clinical usage. For this purpose, treatment planning computed tomography scans of thirty-three consecutive early stage breast cancer patients following breast conservation surgery were analyzed. After delineation of the breast clinical target volume (CTV) and placing opposed wedge paired isocenteric tangential portals, dosimeteric calculations were conducted and dose volume histograms (DVHs) were generated, first with pure 6MV photons and then these calculations were repeated ten times with incorporating 18MV photons (ten percent increase in weight per step) in each individual patient. For each calculation two indexes including maximum dose in the breast CTV ($D_{max}$) and the volume of CTV which covered with 95% Isodose line ($V_{CTV,95%IDL}$) were measured according to the DVH data and then normalized values were plotted in a graph. The optimal weight of 18MV photons was defined as the intersection point of $D_{max}$ and $V_{CTV,95%IDL}$ graphs. For creating a model to predict this optimal weight multiple linear regression analysis was used based on some of the breast and tangential field parameters. The best fitting model for prediction of 18MV photons optimal weight in breast radiotherapy using mixed energy technique, incorporated chest wall separation plus central lung distance (Adjusted R2=0.776). In conclusion, this study represents a model for the estimation of optimal beam weighting in breast radiotherapy using mixed photon energy technique for routine day to day clinical usage.

Evaluations of Si based ternary anode materials by using RF/DC magnetron sputtering for lithium ion batteries

  • 황창묵;박종완
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2010년도 제39회 하계학술대회 초록집
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    • pp.302-303
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    • 2010
  • Generally, the high energy lithium ion batteries depend intimately on the high capacity of electrode materials. For anode materials, the capacity of commercial graphite is unlike to increase much further due to its lower theoretical capacity of 372 mAhg-1. To improve upon graphite-based negative electrode materials for Li-ion rechargeable batteries, alternative anode materials with higher capacity are needed. Therefore, some metal anodes with high theoretic capacity, such as Si, Sn, Ge, Al, and Sb have been studied extensively. This work focuses on ternary Si-M1-M2 composite system, where M1 is Ge that alloys with Li, which has good cyclability and high specific capacity and M2 is Mo that does not alloy with Li. The Si shows the highest gravimetric capacity (up to 4000mAhg-1 for Li21Si5). Although Si is the most promising of the next generation anodes, it undergoes a large volume change during lithium insertion and extraction. It results in pulverization of the Si and loss of electrical contact between the Si and the current collector during the lithiation and delithiation. Thus, its capacity fades rapidly during cycling. Si thin film is more resistant to fracture than bulk Si because the film is firmly attached to the substrate. Thus, Si film could achieve good cycleability as well as high capacity. To improve the cycle performance of Si, Suzuki et al. prepared two components active (Si)-active(Sn, like Ge) elements film by vacuum deposition, where Sn particles dispersed homogeneously in the Si matrix. This film showed excellent rate capability than pure Si thin film. In this work, second element, Ge shows also high capacity (about 2500mAhg-1 for Li21Ge5) and has good cyclability although it undergoes a large volume change likewise Si. But only Ge does not use the anode due to its costs. Therefore, the electrode should be consisted of moderately Ge contents. Third element, Mo is an element that does not alloys with Li such as Co, Cr, Fe, Mn, Ni, V, Zr. In our previous research work, we have fabricated Si-Mo (active-inactive elements) composite negative electrodes by using RF/DC magnetron sputtering method. The electrodes showed excellent cycle characteristics. The Mo-silicide (inert matrix) dispersed homogeneously in the Si matrix and prevents the active material from aggregating. However, the thicker film than $3\;{\mu}m$ with high Mo contents showed poor cycling performance, which was attributed to the internal stress related to thickness. In order to deal with the large volume expansion of Si anode, great efforts were paid on material design. One of the effective ways is to find suitably three-elements (Si-Ge-Mo) contents. In this study, the Si based composites of 45~65 Si at.% and 23~43 Ge at.%, and 12~32 Mo at.% are evaluated the electrochemical characteristics and cycle performances as an anode. Results from six different compositions of Si-Ge-Mo are presented compared to only the Si and Ge negative electrodes.

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관상동맥 재협착 방지를 위한 치료에서 $^{32}$ P 핵종의 선원 형태에 따른 선량분포에 관한 연구 (A Study on the dose distribution produced by $^{32}$ P source form in treatment for inhibiting restenosis of coronary artery)

  • 김경화;김영미;박경배
    • 한국의학물리학회지:의학물리
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    • 제10권1호
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    • pp.1-7
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    • 1999
  • 본 연구에서는 $\beta$선 방출 동위원소들 중에서 $^{32}$P으로부터 방출되는 $\beta$선에 의한 홉수선량 분포를 방사선원의 형태와 기하학적인 조건을 달리하여 컴퓨터를 이용한 모사실험을 통해 예측함으로써 balloon catheter 및 radioactive stent의 이용과 관련된 정보를 얻고자한다. $^{32}$p로부터 방출된 $\beta$선이 인체내에서 에너지를 전달하는 과정에 대한 모사실험은 EGS4 code system 을 이용하여 수행되었다. 인체내의 방사선 흡수선량은 선원의 형태와 위치를 고려하여 축방향과 반경방향으로 등간격으로 나누어 각 격자에서 계산되었다. $^{32}$P 에서 방출되는 $\beta$선 에너지는 Coulomb 포텐셜에 대한 Dirac방정식의 해를 이용하여 계산된 $\beta$선 스펙트럼의 결과를 사용하여 무작위로 선정되었다. 체적 선원과 표면선원에서 시료 표면으로부터 반경방향으로 깊이 0.5 mm내에 있는 표적체에서의 선량률은 각각 12.133 cGy/s per GBq (0.449 cGy/s per mCi, uncertainty: 1.51%)와 24.732 cGy/s per GBq (0.915 cGy/s per mCi, uncertainty: 1.01 %)이다. 선량률은 시료표면으로부터 축방향과 반경방향으로의 거리에 따라 감소한다. 본 연구 결과를 근거로하여 balloon catheter 및 radioactive stent에 $^{32}$P 핵종을 사용할 때 치료선량을 20 Gy로 할 경우 치료에 적합한 초기 방사능량은 각각 29.69 mCi(치료시간을 3분으로 제한할 때) 와 1.2278 $\mu$Ci (영구삽입)로 계산되었다. 또한 원통형 체적선원과 표면선원에 대하여 초기방사능의 크기를 1 mCi/ml의 방사능 체적 밀도와 0.1 mCi/$cm^2$의 방사능 면 밀도로 나타내었을 때 각 표적체에서의 흡수선량률을 계산하였다. 통일한 값의 방사능 체적 밀도와 방사능 면 밀도는 크기가 다른 모델에 대해서 비슷한 크기의 홉수선량을 유도하므로 $^{32}$p 방사선원의 초기 방사능 체적 밀도와 초기 방사능 면 밀도를 알고 있을 때 본 연구의 계산 결과를 이용하면 직경과 길이가 다른 $^{32}$P 핵종의 원통형 모델 주위의 홉수선량 분포를 쉽게 계산할 수 있다.

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질소 보호 가스 첨가가 하이퍼 듀플렉스 스테인리스 밀봉용접재의 마모부식 저항성에 미치는 영향 (Influence of the nitrogen gas addition in the Ar shielding gas on the erosion-corrosion of tube-to-tube sheet welds of hyper duplex stainless steel)

  • 김혜진;전순혁;김순태;이인성;박용수
    • Corrosion Science and Technology
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    • 제13권2호
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    • pp.70-80
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    • 2014
  • Duplex stainless steels with nearly equal fraction of the ferrite(${\alpha}$) phase and austenite(${\gamma}$) phase have been increasingly used for various applications such as power plants, desalination facilities due to their high resistance to corrosion, good weldability, and excellent mechanical properties. Hyper duplex stainless steel (HDSS) is defined as the future duplex stainless steel with a pitting resistance equivalent (PRE=wt.%Cr+3.3(wt.%Mo+0.5wt.%W)+30wt.%N) of above 50. However, when HDSS is welded with gas tungsten arc (GTA), incorporation of nitrogen in the Ar shielding gas are very important because the volume fraction of ${\alpha}$-phase and ${\gamma}$-phase is changed and harmful secondary phases can be formed in the welded zone. In other words, the balance of corrosion resistance between two phases and reduction of $Cr_2N$ are the key points of this study. The primary results of this study are as follows. The addition of $N_2$ to the Ar shielding gas provides phase balance under weld-cooling conditions and increases the transformation temperature of the ${\alpha}$-phase to ${\gamma}$-phase, increasing the fraction of ${\gamma}$-phase as well as decreasing the precipitation of $Cr_2N$. In the anodic polarization test, the addition of nitrogen gas in the Ar shielding gas improved values of the electrochemical parameters, compared to the Pure Ar. Also, in the erosion-corrosion test, the HDSS welded with shielding gas containing $N_2$ decreased the weight loss, compared to HDSS welded with the Ar pure gas. This result showed the resistance of erosion-corrosion was increased due to increasing the fraction of ${\gamma}$-phase and the stability of passive film according to the addition $N_2$ gas to the Ar shielding gas. As a result, the addition of nitrogen gas to the shielding gas improved the resistance of erosion-corrosion.

Surgical indication analysis according to bony defect size in pediatric orbital wall fractures

  • Kim, Seung Hyun;Choi, Jun Ho;Hwang, Jae Ha;Kim, Kwang Seog;Lee, Sam Yong
    • 대한두개안면성형외과학회지
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    • 제21권5호
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    • pp.276-282
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    • 2020
  • Background: Orbital fractures are the most common pediatric facial fractures. Treatment is conservative due to the anatomical differences that make children more resilient to severe displacement or orbital volume change than adults. Although rarely, extensive fractures may result in enophthalmos, causing cosmetic problems. We aimed to establish criteria for extensive fractures that may result in enophthalmos. Methods: We retrospectively reviewed the charts of patients aged 0-15 years diagnosed with orbital fractures in our hospital from January 2010 to February 2019. Computed tomography images were used to classify the fractures into linear, trapdoor, and open-door types, and to estimate the defect size. Data on enophthalmos severity (Hertel exophthalmometry results) and fracture pattern and size at the time of injury were obtained from patients who did not undergo surgery during the follow-up and were used to identify the surgical indications for pediatric orbital fractures. Results: A total of 305 pediatric patients with pure orbital fractures were included-257 males (84.3%), 48 females (15.7%); mean age, 12.01±2.99 years. The defect size (p=0.002) and fracture type (p=0.017) were identified as the variables affecting the enophthalmometric difference between the eyes of non-operated patients. In the linear regression analysis, the variable affecting the fracture size was open-door type fracture (p<0.001). Pearson's correlation analysis demonstrated a positive correlation between the enophthalmometric difference and the bony defect size (p=0.003). Using receiver operating characteristic curve analysis, a cutoff value of 1.81 ㎠ was obtained (sensitivity, 0.543; specificity, 0.724; p=0.002). Conclusion: The incidence of enophthalmos in pediatric pure orbital fractures was found to increase with fracture size, with an even higher incidence when open-door type fracture was a cofactor. In clinical settings, pediatric orbital fractures larger than 1.81 ㎠ may be considered as extensive fractures that can result in enophthalmos and consequent cosmetic problems.

Diffusion Tensor-Derived Properties of Benign Oligemia, True "at Risk" Penumbra, and Infarct Core during the First Three Hours of Stroke Onset: A Rat Model

  • Chiu, Fang-Ying;Kuo, Duen-Pang;Chen, Yung-Chieh;Kao, Yu-Chieh;Chung, Hsiao-Wen;Chen, Cheng-Yu
    • Korean Journal of Radiology
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    • 제19권6호
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    • pp.1161-1171
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    • 2018
  • Objective: The aim of this study was to investigate diffusion tensor (DT) imaging-derived properties of benign oligemia, true "at risk" penumbra (TP), and the infarct core (IC) during the first 3 hours of stroke onset. Materials and Methods: The study was approved by the local animal care and use committee. DT imaging data were obtained from 14 rats after permanent middle cerebral artery occlusion (pMCAO) using a 7T magnetic resonance scanner (Bruker) in room air. Relative cerebral blood flow and apparent diffusion coefficient (ADC) maps were generated to define oligemia, TP, IC, and normal tissue (NT) every 30 minutes up to 3 hours. Relative fractional anisotropy (rFA), pure anisotropy (rq), diffusion magnitude (rL), ADC (rADC), axial diffusivity (rAD), and radial diffusivity (rRD) values were derived by comparison with the contralateral normal brain. Results: The mean volume of oligemia was $24.7{\pm}14.1mm^3$, that of TP was $81.3{\pm}62.6mm^3$, and that of IC was $123.0{\pm}85.2mm^3$ at 30 minutes after pMCAO. rFA showed an initial paradoxical 10% increase in IC and TP, and declined afterward. The rq, rL, rADC, rAD, and rRD showed an initial discrepant decrease in IC (from -24% to -36%) as compared with TP (from -7% to -13%). Significant differences (p < 0.05) in metrics, except rFA, were found between tissue subtypes in the first 2.5 hours. The rq demonstrated the best overall performance in discriminating TP from IC (accuracy = 92.6%, area under curve = 0.93) and the optimal cutoff value was -33.90%. The metric values for oligemia and NT remained similar at all time points. Conclusion: Benign oligemia is small and remains microstructurally normal under pMCAO. TP and IC show a distinct evolution of DT-derived properties within the first 3 hours of stroke onset, and are thus potentially useful in predicting the fate of ischemic brain.

수도 품종의 혼식재배가 생육 및 수량에 미치는 영향 (Effect of Mixed Cultivation of Two Rice Cultivars on Rice Growth and Grain Yield)

  • 박성태;김순철;이수관
    • 한국작물학회지
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    • 제32권1호
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    • pp.24-33
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    • 1987
  • 상반된 생육형질을 가진 두 품종을 혼식재배할 때 경합반응 및 수량에 미치는 영향을 구명, 혼식재배에 의한 수량증대 가능성을 구명하기 위해 혼식방법시험과 혼식비율시험을 2년간('84∼'85)에 걸쳐 영남작물시험장 수도 시험포에서 수행한 시험결과를 요약하면 다음과 같다. 1. 광합성 효율은 이앙후 30일∼45일 사이에 높았으며, 특히 혼식재배구는 생육초기의 광합성 효율이 단일재배구에 비하여 높았다. 2. 건물중 높은 품종을 50% 이상 혼식했을 때대체로 혼식구는 두 품종의 단일재배구의 건물중 평균치보다는 같거나, 높았으며 건물중이 높았던 품종보다는 낮았고, 혼식비율에 따른 건물중 반응은 낙동벼와 태백벼에 비하여 각각 밀양 2003, 삼강벼가 convex 반응을 나타내어 이들 품종이 경합력이 강함을 보여 주었다. 3. 수확지수는 단일재배구에 비하여 교대이앙구는 높지 않았으나 밀양 2003 75%: 낙동벼 25%, 삼강벼 50%: 태백에 50% 혼식구에서는 수량지가 높았던 품종보다 2∼3% 높아, 혼식재배를 통해 수확지수의 증대효과를 기대할 수 있었다. 4. 혼식구의 수량성은 수량성이 높은 품종의 혼식비율을 50% 이상 높을수록 높은 경향이었는데 이것은 두 품종의 단일재배구 평균치보다는 높았으나 25% 혼합시는 3∼4 % 감수하였고, 혼합비율에 따른 수량성은 단일재배구의 수량이 높았던 품종보다는 높지 않았다. 5. 1 열교대이앙구는 단일품종재배구의 두 품종의 평균치보다는 밀양 2003, 낙동벼 조합에서는 2% 증수되었으나 삼강벼, 태백벼, 조합에서는 4% 감수하였고 수량성이 높은 품종보다는 낮았다. 6. 혼식시 절대수량은 수량성이 높았던 품종의 혼식율을 높였던 구가 증수되었으나 혼식효과는 혼식율을 낮추었던 구가 오히려 높았다. 7. 혼식비율에 따른 두 품종간 수량구성비율은 상가적 이론치보다 실제치가 밀양2003 5∼l2%, 삼강벼가 3∼6% 높은 반면 낙동벼, 태백벼는 각각 같은 정도로 떨어졌다. 8. 혼식재배시 두 품종간의 수량 구성비율은 단일품종재배에서 보다 밀양 2003 삼강벼가 낙동벼와 태백벼 보다 각각 증가하였다.

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