• 한국환경농학회지
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• 제40권4호
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• pp.359-365
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• 2021

BACKGROUND: Prohexadione-calcium (PC) is a plant growth regulator of cyclohexanedione family acting on inhibiting gibberellin biosynthesis and has been used to regulate shoot elongation of turfgrass in the golf course during the summer season. This study was conducted to investigate the effects of PC on the inhibition of shoot elongation, growth, and nitrogen uptake in Zoysia matrella. METHODS AND RESULTS: Treatments were as follows; non-treatment, control (TE 0.01 a.i. g/m²/100 mL), 0.0025PC (PC 0.0025 a.i. g/m²/100 mL), 0.005PC (PC 0.005 a.i. g/m²/100 mL), 0.01PC (PC 0.01 a.i. g/m²/100 mL) and 0.02PC (PC 0.02 a.i. g/m²/100 mL). Visual quality and chlorophyll content were not significantly different. As compared to non-treatment, shoot length and clipping yield in 0.005PC, 0.01PC and 0.02PC treatments were decreased by 29-36% and 65-82%, respectively, and those of 0.0025PC were not significantly different. N uptake of Z. matrella after applying PC was decreased by 28.9-77.8% than that of non-treatment. Inhibition effects of PC treatment in Z. matrella were not significantly different from those of control. CONCLUSION(S): These results indicated that the application of prohexadione calcium inhibited shoot elongation, clipping yield and N uptake amount in Z. matrella, and trinexapac-ethyl could be replaced with prohexadione-calcium in turfgrass management.

• 소성∙가공
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• 제10권2호
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• pp.130-136
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• 2001

The mathematical set-up model was developed to reduce the mechanical property deviation in annealed and slightly rolled steel strip. The mechanical peculiarities of skin pass rolling process, such as high friction value and non-circular contact arc, low reduction and non-negligible entry and exit elastic zones as well as central restricted deformation zone are all taken into account. The deformation of work rolls is calculated with the influence function method and arbitrary contact arc shape is permitted. The strip deformation is modeled by slab method and the entry and exit elastic deformation zones are included. The strip restricted deformation zone near the neutral point is also considered. It was revealed that the new model has better accuracy than present regression model by statistical analysis with actual mill rolling data.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.317-317
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• 2000

The mathematical set-up model was developed to reduce the mechanical property deviation in annealed and slightly rolled steel strip. The mechanical peculiarities of temper rolling process, such as high friction value and non-circular contact arc, Low reduction and non-negligible entry and exit elastic zones as well as central restricted deformation zone are all taken into account. The deformation of work rolls is calculated with the influence function method and arbitrary contact arc shape is permitted. The strip deformation is modeled by slab method and the entry and exit elastic deformation zones are included. The restricted deformation Bone near the neutral point is also considered. It was revealed that the new model has better accuracy than present regression model by statistical analysis with actual mill rolling data.

• 소성∙가공
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• 제13권5호
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• pp.403-408
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• 2004

Hydroformability of 6061 and 7075 aluminum tube materials was studied by warm hydroforming experiments. A special tooling and heating system was designed and manufactured in order to perform warm hydroforming between room temperature and $300^{\circ}C$. The control of tube temperature for warm hydroforming was made by the control of temperature of oil medium. Warm hydroformability was analyzed by tube appearances, tube elongation and hardness values. Hydroforming characteristics of 6061 and 7075 tubes showed different temperature dependence between room temperature and $300^{\circ}C$. The difference in hydroformabilities of 6061 and 7075 at elevated temperatures was interpreted by the different sensitivity to dynamic strain aging of both aluminum materials.

• 열처리공학회지
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• 제10권2호
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• pp.109-120
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• 1997

Microstructure and mechanical properties of Fe-Si-Mn-P high strength steel sheet have been investigated by controlling the cooling rate. Bainite and ferrite were obtatined by annealing in the ferrite pluse austenite region, and ferrite and austenite were obtatined after annealing in the fully austenite region. Ferrite and pearlite were obtained when the cooling rate was controlled from the annealing temperature above $760^{\circ}C$ and bainite showed with increasing cooling rate, however below $760^{\circ}C$ ferrite and bainite were obtained. Tensile strengths and hardness nearly unchanged with increasing cooling rate after control the cooling rate from the temperature above $760^{\circ}C$, while tensile strengths increased and elongation decreased with increasing cooling rate when the cooling rate was controlled from the tempeature below $760^{\circ}C$. Without regard to annealing temperature, tensile strength increased and elongation decreased with increasing cooling rate. Tensile strengths and elongation values heat treated in the ferrite plus austenite region were higher than those in the fully austenite region. Retained austenite and strength-elongation balance showed the maximum value at $780^{\circ}C$ and decreased with increasing annealing temperature. Strength-elongation balance value was controlled by the retained austenite.

• Restorative Dentistry and Endodontics
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• 제16권1호
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• pp.209-215
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• 1991

The propose of this study was to evaluate the effect of the variuos antiseptic solutions and distilled water on physical properties of endodontic gutta-percha cone. The antiseptic solutions were 70% isoprophyl alcohol, 5% NaOCl and 2.5% NaOCl, as control gutta-percha cones, did not stored antiseptic solution was used. Observation periods were 1, 5, 10, 20, and 30 days. In each group,. the 15 gutta-percha cones used. A tensile strength and elongation rate measurements were performed with Instron (Instron 4501), cross - head speed was set 10 inch / min. The data were statistically analyzed and the results were as followed. 1. The tensile strength of the gutta-percha cones, stored in distilled water, were slightly decreased (p<0.05). Elongation rate was not significantly different 2. The tensile strength of the gutta-percha cones, stored in 70% isopropyl alcohol, were increased (p<0.01) except 1 day group. 3. The tensile strength of the gutta-percha cone, stored in 2.5% NaOCl, were decreased (p<.0.05). Elongation rate significantly decreased (p<0.01). 4. The tensile strength of the gutta-percha cone, stored in 5% NaOCl, were decreased (p<0.05). Elongation rate significantly decreased (p<0.01). These results showed that the changes of physical properties (tensile strength and elongation rate) in gutta-percha cone were developed after a day' when gutta-percha cone were stored at 70% isopropyl alcohol, 2.5% or 5% NaOCl. So, It was concluded that gutta-percha cone must have been used at least within one day, when they were stored at the above antiseptics. I thought that the study of substantial effects on endodontic treatment due to changes of physical properties in gutta-percha cone will be needed.

• Clinics in Shoulder and Elbow
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• 제19권3호
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• pp.155-162
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• 2016

Background: The study aimed to determine the type of capsular insertion and the extent of capsular elongation in anterior shoulder instability by quantitatively evaluating their computed tomography arthrographic (CTA) findings, and to investigate the correlation of these parameters with surgical outcomes. Methods: We retrospectively reviewed 71 patients who underwent CTA and arthroscopic capsulolabral reconstruction for anterior shoulder instability between April 2004 and August 2008. The control group comprised 72 patients diagnosed as isolated type II superior labrum anterior to posterior (SLAP) lesion during the period. Among the 143 patients, 71 were examined with follow-up CTA at an average 13.8 months after surgery. It was measured the capsular length and cross-sectional area at two distinct capsular regions: the 4 and 5 o'clock position of the capsule. Results: With regards to the incidence of the type of anterior capsular insertion, type I was more common in the control group, whereas type III more common than in the instability group. Anterior capsular length and cross-sectional area were significantly greater in the instability group than in the control group. Among patients of the instability group, the number of dislocations and the presence of anterior labroligamentous periosteal sleeve avulsion lesion were significantly associated with anterior capsular redundancy. Postoperatively, recurrence was found in 3 patients (4.2%) and their postoperative capsular length and cross-sectional area were greater than those of patients without recurrence. Conclusions: Capsular insertion type and capsular redundancy derived through CTA may serve as important parameters for the management of anterior shoulder instability.

• 혜화의학회지
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• 제29권1호
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• pp.18-25
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• 2020

Objective: The goal of this study is to investigate whether peripheral axonal regeneration is affected by diabetes in experimental animals. Method: Sprague Dawely rat was injected with 45~50 mg/kg of streptozotocin (STZ) to generate an animal model of diabetes. Three months after STZ injection, sciatic nerve (2 cm length) was removed and the same length of nerve segments from STZ-injected animal or from control animal (CTL) was transplanted into STZ-injected animals (STZ-STZ and STZ-CTL respectively). Similarly, sciatic nerve segments from STZ-injected animal or from control animal were grafted into the control animals (CTL-STZ and CTL-CTL respectively). All animals were sacrificed 2 weeks after transplantation. Sciatic nerve sections were prepared and subjected to immunofluorescence staining analysis. Results: Immunofluorescence staining for NF-200 showed that distal elongation of regenerating axons reached 40~80% of proximal neve in both CTL-STZ and CTL-CTL groups. However, distal elongation in both STZ-STZ and STZ-CTL groups were 20~60% of proximal nerve. Furthermore, measurement of axonal regeneration after immuno-staining with SCG10 showed that the scores of distal elongation relative to proximal nerve were 50~90% in CTL-CTL and CTL-STZ groups and 10-60% in STZ-CTL and STZ-STZ. Conclusions: Our data showed that the levels of axonal regeneration were not affected irrespective of whether they were from STZ- or CTL graft, but were greatly reduced when the nerves were transplanted into the STZ host.

• Corrosion Science and Technology
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• 제2권6호
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• pp.283-288
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• 2003

The cathodic protection method is being widely used in marine structural steel, however a high tensile steel like RE 36 steel for marine structural steel is easy to get hydrogen embrittlement due to over protection during cathodic protection as well as preferential corrosion of HAZ(Heating Affected Zone) part. In this paper, corrosion resistance and mechanical properties such as elongation and hydrogen embrittlement were investigated with not only in terms of electrochemical view but also SSRT(Slow Strain Rate Test) method with applied constant cathodic potential, analysis of SEM fractography in case of both As-welded and PWHT(Post-Weld Heat Treatment) of $550^{\circ}C$. The best effect for corrosion resistance was apparently indicated at PWHT of $550^{\circ}C$ and elongation was increased with PWHT of $550^{\circ}C$ than that of As-welded condition. On the other hand. Elongation was decreased with applied potential shifting to low potential direction which may be caused by hydrogen embrittlement, however the susceptibility of hydrogen embrittlement was decreased with PWHT of $550^{\circ}C$ than that of As-welded condition and Q.C(quasi cleavage) fracture mode was also observed significantly according to increasing of susceptibility of hydrogen embrittlement. Eventually it is suggested that an optimum cathodic protection potential range not causing hydrogen embrittlernent is from -770 mV(SCE) to -850 mV(SCE) in As-welded condition while is from -770 mV(SCE) to -875 mV(SCE) in PWHT of $550^{\circ}C$.

• 생물환경조절학회지
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• 제18권4호
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• pp.401-407
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• 2009

본 연구는 토마토의 도장 억제를 위하여 보다 안정적인 건묘를 생산하고자 육묘 기간 중 diniconazol 처리시기 처리농도에 따른 경엽처리와 침지 시간에 따른 종자처리가 묘 도장 억제에 미치는 영향을 알아보고 적정 방법을 구명하고자 수행하였다. Diniconazol 처리시기 및 처리농도에 따른 토마토의 초장 신장을 본 결과 1단계 2단계 3단계로 초장의 신장과 절간장 억제가 잘 나타났다. 이는 이른 시기가 늦은 시기보다 식물체가 받는 약제의 양이 더 많기 때문에 약제 효과가 잘 나타났다. 1단계는 4절, 2단계, 3단계는 각각 3절, 2절로 억제된 절간수가 줄어들었다. 약제 지속성이 초장의 신장에 미치는 영향을 본 결과 1단계, 2단계 $5mg{\cdot}L^{-1}$은 약제 처리 후 초장의 신장억제가 나타났으나 다른 처리구에 비해 일정한 시간이 지나면 빨리 회복하는 경향이 나타났다. 3단계에서는 초장 신장 억제 기간이 짧았고 빠른 회복을 보였다. 1단계는 5주, 2단계, 3단계는 각각 4주정도 약제 지속효과가 나타났다. 육묘 종료 후 정식한 결과 생체량이 빨리 증가 되어 생육에는 무처리와 유의차가 없었다.