• 생물환경조절학회지
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• 제11권4호
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• pp.175-180
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• 2002

본 시험은 봄철 노지재배시 막덮기 피복자재가 녹색꽃양배추의 생육 및 수량에 미치는 영향을 구명코자 수행하였다. 막덮기와 유공필름처리에서 무처리에 비하여 3~4$^{\circ}C$의 기온상승 및 2~3$^{\circ}C$지온 상승효과를 보였으며 상대습도에 있어서도 높게 유지되었다. 막덮기와 유공필름처리에서 생체중, 근중 등 생육이 크게 향상되었다. 이상화뢰의 발생은 막덮기 피복처리에서 가장 적었다. 출뢰일은 38~40일로 처리간 큰 차이가 없었으나, 화뢰중은 막덮기 피복과 유공필름처리에서 400g이상으로 무처리에 비하여 2배 이상 증가되었다. 첫 수확일은 막덮기 처리에서 무처리에 비하여 2주 이상 빨라 조기수확이 가능하였다 상품수량에서도 막덮기와 유공필름처리에서 1,600kg/10a이상으로 많았으며 다음이 P.E. 무처리순으로 무처리에서 857kg으로 가장 적었다. 250g 이상의 화뢰중 비율도 막덮기 처리에서 고르게 분포되었다. 이처럼 봄철 막덮기 자재를 이용한 녹색꽃양배추 재배시 조기수확과 증수는 물론 품질향상을 기할 수 있었다

• 한국공간구조학회논문집
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• 제2권1호
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• pp.85-92
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• 2002

Two way grid single-layer domes are of great advantage in fabrication and construction because of the simple fact that they have only four members at each junction. But, from a point of view of mechanics, the rectangular latticed pattern gives rise to a nonuniform rigidity-distribution in the circumferential direction. If the equivalent rigidity is considered in the axial direction of members, the in-plane equivalent shearing rigidity depends only on the in-plane bending rigidity of members and its value is very small in comparison to that of the in-plane equivalent stretching rigidity. It has a tendency to decrease buckling -strength of dome considerably by external force. But it is possible to increase buckling strength by the use of roofing covering materials connected to framework. In a case like this, shearing rigidity of roofing material increases buckling strength of the overall structure and can be designed economically from the viewpoint of practice. Therefore, the purpose of this paper, in Lamella dome and rectangular latticed dome that are a set of 2-way grid dome, is to clarify the effects of roofing covering materials for increasing of buckling strength of overall dome. Analysis method is based on FEM dealing with the geometrically nonlinear deflection problems. The conclusion were given as follows: 1. In case of Lamella domes which have nearly equal rigidity in the direction of circumference, the rigidity of roofing covering materials does not have a great influence on buckling-strength, but in rectangular latticed domes that has a clear periodicity of rigidity, the value of its buckling strength has a tendency to increase considerably with increasing rigidity of roofing covering materials 2. In case of rectangular latticed domes, as rise-span-ratio increases, models which is subjected to pressure -type-uniform loading than vertical-type-uniform loading are higher in the aspects of the increasing rate of buckling- strength according to the rate of shear reinforcement rigidity, but in case of Lamella dome, the condition of loading and rise-span-ratio do not have a great influence on the increasing rate of buckling strength according to the rate of shear reinforcement rigidity.

• 한국자원식물학회지
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• 제13권3호
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• pp.208-212
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• 2000

보온 피복재 종류가 자옥 포도 유목의 월동시 동해방지, 노동력 절감 및 병해 발생 억제에 미치는 영향을 구명하기 위하여 11월 하순에 짚을 덮은 다음 보온덮개B, 킬딩, 칼라부직A 및 백색니들펀칭부직포 등을 피복하여 시험한 결과를 요약하면 다음과 같다. 1. 보온력은 백색니들펀칭부직포가 가장 불량하였고, 다른 보온재간에는 차이가 미미하였다. 2. 발아는 보온덮개B에서 빨리 시작되었으며, 발아 9일 후에도 발아율이 79.7%로 타 보온재 보다 2.3∼12.5% 높았다. 3. 생육은 보온재간에 차이가 없었으며, 병해 발생은 킬딩과 보온덮개B에서 뿌리혹병이 지수 3.0∼3.2로 다소 많이 발생되었을 뿐 기타 병해는 처리간에 차이가 없거나 미미 하였다. 4. 작업 단계별 소요노력은 보온덮개B에 비하여 킬딩은 6% 많았으나, 칼라부직A는 6%, 백색니들펀칭 부직포는 15%적었다.

• 생물환경조절학회지
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• 제13권4호
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• pp.251-257
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• 2004

본 연구는 몇가지 보온피복 재료 및 방법이 플라스틱하우스의 보온력과 토마토의 생육과 수량에 미치는 영향을 구명하고자 수행하였다. 다겹보온덮개(카시미론 8온스 1겹+폴리폼(1 mm) 4겹 +부직포 2겹+폴리프로필렌 1겹+흑색네트차광망 1겹)를 이중하우스 구조의 외면에 피복한 것이 이중하우스 구조의 내부에 피복한 것에 비해 하우스내 야간의 기온과 지온은 약 $ 낮았으나 광투과율이 높아서 토마토 상품수량이 약 $2\%$ 증가하였다. 그리고 다곁보온덮개를 피복하지 않고 이중하우스 구조의 내부에 EVA커튼을 설치한 것에 비해서는 하우스내 야간기온이 $3^{\circ}C$ 높게 유지되어 수확기가 약 1일 빨라지고 토마토 과실도$ 19\%$ 증수하였다. 한편 이중하우스 외면에 다겹보온덮개를 피복하고 내부에 보온커튼(알미늄+직물)을 설치한 것은 다겹보온 덮개를 피복하고 보온커튼을 설치하지 않은 것과 이중하우스에 다겹보온덮개를 피복하지 않고 EVA커튼만 설치한 것에 비해 하우스내 기온이 각각 $2.2^{\circ}C$와 $4.5^{\circ}C$ 높게 유지되었으며 이러한 보온효과에 의해 토마토 과실수량도 각각 $18\%$와 $37\%$ 가되었다. 따라서 본 연구결과는 남부지역에서 저온기에 다겹보온덮개를 이중 플라스틱하우스 구조의 외면에 피복하고 내부에 보온성이 높은 커튼자재를 사용하면 가온을 하지 않거나 최소한의 난방비로 토마토를 재배할 수 있음을 시사해 주었다.

• Structural Engineering and Mechanics
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• 제54권5호
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• pp.955-971
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• 2015

In this paper, the influence of the polled direction of piezoelectric materials on the stress distribution is studied under time-harmonic dynamical load (time-harmonic Lamb's problem). The system considered in this study consists of piezoelectric covering layer and piezoelectric half-plane, and the harmonic dynamical load acts on the free face of the covering layer. The investigations are carried out by utilizing the exact equations of motion and relations of the linear theory of electro-elasticity. The plane-strain state is considered. It is assumed that the perfect contact conditions between the covering layer and half-plane are satisfied. The boundary value problems under consideration are solved by employing Fourier exponential transformation techniques with respect to coordinates directed along the interface line. Numerical results on the influence of the polled direction of the piezoelectric materials such as PZT-5A, PZT-5H, PZT-4 and PZT-7A on the normal stresses, shear stresses and electric potential acting on the interface plane are presented and discussed. As a result of the analyses, it is established that the polled directions of the piezoelectric materials play an important role on the values of the studied stresses and electric potential.

• 원예과학기술지
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• 제33권3호
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• pp.326-330
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• 2015

본 시험은 노지 논고추 터널 재배시 피복용 재료에 따른 고추의 생육 및 수량에 미치는 영향을 조사하기 위하여 수행되었다. 터널 피복용 재료는 일라이트 부직포, P.E 비닐을 사용하였다. 기온과 지온은 일라이트 부직포 및 P.E 비닐 터널 처리구에서 노지보다 각각 $7-8^{\circ}C$, $2-3^{\circ}C$ 높았고, 상대 습도도 터널 설치구가 노지보다 30% 더 높게 유지되었다. 고추의 생육과 수량은 일라이트 부직포 및 P.E 비닐 터널 설치구에서 높았고, 10a당 수량은 일라이트 부직포 및 P.E 비닐을 이용한 터널 재배시 노지 재배 대비 각각 30%, 26% 증수되어 고추 논재배시 수량확보를 위한 재배법으로 적용이 가능할 것으로 판단된다.

• 한국환경복원기술학회지
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• 제3권3호
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• pp.37-44
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• 2000

The objective of this study is on suggesting the simulation model of 10 selected plants for the traffic noise barrier through field experiment by computer. The field experiment was carried out at the traffic noise barrier of Honam highway. The results are as follows. 1. It was identified that Paederia scandens, Celastrus Orbiculatus, Lonicera japonica, Wisteria floribunda, Parthenocissus tricuspidata and Parthenocissus quinquefolia grows well vertically and takes 3 years in covering completely. 2. It was identified that Trachelospermum asiaticum and Hedera rhombea, evergreen Climber(vine), grows slowly in comparative with other deciduous Climbers(vine), but give drivers good landscapes in winter. So those have considerable value in the south region of Taejeon. 3. It was identified that Wisteria jl.oribunda, Lonicera japonica, Paederia scandens, Clematis mandschurica and Campsis grandijlora showed good view in flowering period. 4. It was identified that auxiliary materials for inducing growth were needed in other plants except Parthenocissus tricuspidata, Parthenocissus quinquefolia. 5. It was identified that subsequent research about the auxiliary materials for inducing growth and adequate planting distance of each plants is needed for actual application.

• Restorative Dentistry and Endodontics
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• 제43권4호
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• pp.48.1-48.13
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• 2018

Objectives: To analyze the influence of thickness and incisal extension of indirect veneers on the stress and strain generated in maxillary canine teeth. Materials and Methods: A 3-dimensional maxillary canine model was validated with an in vitro strain gauge and exported to computer-assisted engineering software. Materials were considered homogeneous, isotropic, and elastic. Each canine tooth was then subjected to a 0.3 and 0.8 mm reduction on the facial surface, in preparations with and without incisal covering, and restored with a lithium disilicate veneer. A 50 N load was applied at $45^{\circ}$ to the long axis of the tooth, on the incisal third of the palatal surface of the crown. Results: The results showed a mean of $218.16{\mu}strain$ of stress in the in vitro experiment, and $210.63{\mu}strain$ in finite element analysis (FEA). The stress concentration on prepared teeth was higher at the palatal root surface, with a mean value of 11.02 MPa and varying less than 3% between the preparation designs. The veneers concentrated higher stresses at the incisal third of the facial surface, with a mean of 3.88 MPa and a 40% increase in less-thick veneers. The incisal cover generated a new stress concentration area, with values over 48.18 MPa. Conclusions: The mathematical model for a maxillary canine tooth was validated using FEA. The thickness (0.3 or 0.8 mm) and the incisal covering showed no difference for the tooth structure. However, the incisal covering was harmful for the veneer, of which the greatest thickness was beneficial.

• 대한금속재료학회지
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• 제48권2호
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• pp.180-186
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• 2010

For the application of field emission display (FED), it is essential to develop a carbon nanotube (CNT) cathode with high emission current density. In this study, we developed and demonstrated a post-heat treatment (PHT) process to improve field emission properties of CNT cathodes. Since the PHT is intended to burn out organic materials covering the CNTs, the PHT was carried out by heating samples at a high temperature in an atmosphere. The PHT process is applied for samples processed by surface treatment with an adhesive tape. Compared to samples prior to the PHT, samples after the PHT at $360^{\circ}C$ showed about 17% improvement in emission current density. The major reason for the increased current density is mainly the increased aspect ratio of the CNTs because of the removal of the adhesive organic residues covering the CNTs, which were attached on the CNT surfaces during the surface treatment using the adhesive taping method.

• 원예과학기술지
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• 제35권1호
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• pp.79-87
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• 2017

We examined the effect of two greenhouse covering materials (glass or solid polycarbonate sheets) on the light environment and growth of tomato and cucumber plants. Spectral analysis showed that polycarbonate sheets entirely blocked radiation in both the UV - B (300 - 320 nm) and UV - A (320 - 400 nm) ranges, whereas glass transmitted UV - A and was only opaque to UV - B. The transmittance of photosynthetically active radiation (400 - 700 nm) and near infrared radiation (700 - 1100 nm) was higher in polycarbonate than glass. Air and soil temperatures were not significantly different between greenhouses covered with either material. The growth of cucumber plants was slightly affected by covering materials, whereas no significant changes in growth parameters were observed for tomato plants. The color parameters of tomato fruits were affected by the cover material, whereas cucumber fruits showed similar coloration in both glass and polycarbonate greenhouses.