• Korean Journal of Acupuncture
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• 제33권4호
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• pp.149-156
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• 2016

Objectives and Methods : The aim of this study was to investigate twirling and supplementation and draining by analyzing ancient acupuncture literature and modern research papers, and to discuss the quantitative standards for the procedure. Results : Twirling supplementation and draining techniques were first described in Huang do neijing, after which they were recorded in various other ancient acupuncture texts. Not only were these techniques used in the active treatment of patient historically, but they also form the foundations of modern-day acupuncture treatment. Twirling supplementation and draining techniques described in ancient literatures can be divided into Yin and Yang. Examples of Yang characteristics include Up, Male, Morning, Hands, the governor vessel, Outside, and Left. The left rotation technique is a reinforcing method performed by moving the thumb forward while rotating the needle. Examples of Yin characteristics include Down, Female, Afternoon, Foot, the conception vessel(CV), Inside, and Right. The right rotation technique is a reducing method performed by moving the thumb backward while rotating the needle. Twirling supplementation and draining has been divided for four ways by classical literature and research that worked before. the direction of acupuncture, the stimulus-quantity of acupuncture, the performance of doctor(the uses of both hands, left and right hand) and the feeling of patient. Conclusions : Therefore, continuous research is required to implement Twirling supplementation and draining in a consistent manner. In addition, more active clinical trials using the techniques are necessary as well.

• Journal of Power Electronics
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• 제9권1호
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• pp.74-84
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• 2009

The design and implementation of a high performance PID (Proportional Integral & Differential) style controller with zero-phase error tracking property is considered in this article. Unlike a ball screw driven system, the controller in a direct drive system should provide a high level of tracking performance while avoiding the problems due to the absence of the gear system. The stiff mechanical element in a direct drive system allows high precise positioning capability, but relatively high tracking ability with minimal position error is required. In this work, a feasible position controller named 'Unified PID controller' is presented. It will be shown that the function of the closed position loop can be designed into unity gain system in continuous time domain to provide minimal position error. The focus of this work is in two areas. First, easy gain tunable PID position controller without speed control loop is designed in order to construct feasible high performance drive system. Second, a simple but powerful zero phase error tracking strategy using the pre-designed function of the main control loop is presented for minimal tracking error in all operating conditions. Experimental results with a s-curve based position pattern commonly used in industrial field demonstrate the feasibility and effective performance of the approach.

• Steel and Composite Structures
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• 제48권5호
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• pp.547-564
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• 2023

This study investigates the effect of bolt preloading on the rotational stiffness of stainless steel end-plate connections. An experimental programme incorporating 11 full-scale joint specimens are carried out comparing the behaviours of fully pre-tensioned (PT) and snug-tightened (ST) flush/extended end-plate connections, made of austenitic or lean duplex stainless steels. It is observed from the tests that the presence of bolt preloading leads to a significant increase in the rotational stiffness. A parallel finite element analysis (FEA) validated against the test results demonstrates that the geometric imperfection of end-plate has a strong influence on the moment-rotation response of preloaded end-plate connections, which is crucial to explain the observed "two-stage" behaviour of these connections. Based on the data obtained from the tests and FE parametric study, the performance of the Eurocode 3 predictive model is evaluated, which exhibits a significant deviation in predicting the rotational stiffness of stainless steel end-plate connections. A modified bi-linear model, which incorporates three key properties, is therefore proposed to enable a better prediction. Finally, the effect of bolt preloading is demonstrated at the system (structure) level considering the serviceability of semi-continuous stainless steel beams with end-plate connections.

• Steel and Composite Structures
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• 제31권4호
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• pp.373-385
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• 2019

This paper presents a useful in-plane structural analysis of low-rise blind-bolted composite frames with semi-rigid joints. Analytical models were used to predict the moment-rotation relationship of the composite beam-to-column flush endplate joints that produced accurate and reliable results. The comparisons of the analytical model with test results in terms of the moment-rotation response verified the robustness and reliability of the model. Abaqus software was adopted to conduct frame analysis considering the material and geometrical non-linearities. The flexural behaviour of the composite frames was studied by applying the lateral loads incorporating wind and earthquake actions according to the Australian standards. A wide variety of frames with a varied number of bays and storeys was analysed to determine the bending moment envelopes under different load combinations. The design models were finalized that met the strength and serviceability limit state criteria. The results from the frame analysis suggest that among lateral loads, wind loads are more critical in Australia as compared to the earthquake loads. However, gravity loads alone govern the design as maximum sagging and hogging moments in the frames are produced as a result of the load combination with dead and live loads alone. This study provides a preliminary analysis and general understanding of the behaviour of low rise, semi-continuous frames subjected to lateral load characteristics of wind and earthquake conditions in Australia that can be applied in engineering practice.

• 한국정밀공학회지
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• 제7권1호
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• pp.37-52
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• 1990

In this study, the characteristics of cooling and rolling during strip casting process is obtained in comparison with the experimental and analytical results. The prupose of this study is to effectively analyze the thermal and mechanical deformation of roller applying the results of the heat transfer and the pressure distribution to boundary conditions. And then the relation between strip thickness and roll deformation is shown. The second purpose is to obtain the proper condition of the continuous casting for stainless steel. The summary and conclusions can be made on the basis of the results obtained by the theories and experiments. a) The strip casting condition for the fine surface quality of tin-alloy as-cast material was obtained in accordance with the velocity of roll rotation and initial roll gap. b) The experimental condition that the dimension of the cast strip thickness coincide with that of the initial roll gap was according to the experimental result of continuous casting by twin-roll type. c) The thermoelastic finite element model to calculate the roll deformation is represented. Thermoelastic model prediction for the roll deformation are in good agreement with the experimental results considering the thermal expansion of the roll. d) The higher cooling rates were obtained by a twin-roller quenching technique. Also quenched microstructure of the rapidly solidified shell was verified. e) The magnitude of roll deformation due to the thermal expansion and roll separating force is quantit- atively represented in the analysis of continuous casting for stainless steel.

• 대한치과교정학회지
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• 제49권6호
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• pp.349-359
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• 2019

Objective: The aim of this study was to analyze three-dimensional (3D) changes in maxillary dentition in Class II malocclusion treatment using arch wire with continuous tip-back bends or compensating curve, together with intermaxillary elastics by superimposing 3D virtual models. Methods: The subjects were 20 patients (2 men and 18 women; mean age 20 years 7 months ${\pm}$ 3 years 9 months) with Class II malocclusion treated using $0.016{\times}0.022-inch$ multiloop edgewise arch wire with continuous tip-back bends or titanium molybdenum alloy ideal arch wire with compensating curve, together with intermaxillary elastics. Linear and angular measurements were performed to investigate maxillary teeth displacement by superimposing pre- and post-treatment 3D virtual models using Rapidform 2006 and analyzing the results using paired t-tests. Results: There were posterior displacement of maxillary teeth (p < 0.01) with distal crown tipping of canine, second premolar and first molar (p < 0.05), expansion of maxillary arch (p < 0.05) with buccoversion of second premolar and first molar (p < 0.01), and distal-in rotation of first molar (p < 0.01). Reduced angular difference between anterior and posterior occlusal planes (p < 0.001), with extrusion of anterior teeth (p < 0.05) and intrusion of second premolar and first molar (p < 0.001) was observed. Conclusions: Class II treatment using an arch wire with continuous tip-back bends or a compensating curve, together with intermaxillary elastics, could retract and expand maxillary dentition, and reduce occlusal curvature. These results will help clinicians in understanding the mechanism of this Class II treatment.

• 한국환경농학회지
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• 제32권4호
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• pp.279-286
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• 2013

본 연구는 시설하우스 당근 연작장해 경감을 위한 녹비작물 재배가 당근의 생육특성 및 수량에 미치는 영향을 알아보기 위한 연구로서 하계녹비작물인 크로타라리아 및 수단글라스를 실제 당근 연작재배지에 단파 및 혼파로 구분하여 파종하였으며, 생육된 녹비작물의 양분공급량을 조사하였고, 녹비작물의 토양환원 후 토양의 이화학적 특성을 조사하였으며, 녹비작물 토양에 환원 후 후작물인 당근의 생육특성 및 당근의 장해율과 상품수량을 조사하여 녹비작물의 당근 연작장해 경감효과를 조사하였다. 시설하우스 당근 연작재배지서 생육된 녹비작물의 질소(N), 인($P_2O_5$), 칼륨($K_2O$), 칼슘(CaO) 및 마그네슘(MgO) 공급량은 크로타라리아의 경우 각각 8.3, 7.5, 4.4, 7.8 및 2.1 kg/10a이었으며, 수단글라스의 경우 각각 8.4, 8.6, 26.8, 0.3 및 2.7 kg/10a이었으며, 혼파의 경우는 단파와 유사한 경향이었다. 당근 연작재배지에서 녹비작물의 토양환원 전 후 토양의 물리학적 특성을 조사한 결과 용적밀도는 녹비작물 처리구가 대조구에 비해 감소하는 경향이었고, 공극률은 증가하는 경향이었다. 토양환원 전 후 토양의 pH는 대조구와 별다른 차이 없이 6.37-6.64 범위였으며, EC는 크로타라리아(2.86 dS/m) 및 수단글라스(2.24 dS/m) 처리구가 대조구(3.14 dS/m)에 비해 낮았다. 토양 중 유기물, T-N 및 avail. $P_2O_5$ 함량은 녹비작물 처리구가 대조구에 비해 증가하는 경향이었다. 녹비작물 토양환원에 따른 후작물인 당근의 총 생산량은 크로타라리아 처리구에서 7,916 kg/10a로 가장 높은 수량을 보였으며, 대조구의 경우는 6,869 kg/10a로 가장 낮았다. 장해율은 대조구, 관행처리구, 크로타라리아, 수단글라스, 수단글라스 + 크로타라리아 처리구에서 각각 34.9, 23.1, 21.4, 22.9 및 19.8%로 혼파 처리구에서 가장 낮은 장해율을 보였다. 당근의 상품수량은 크로타라리아 처리구(6,226 kg $10a^{-1}$)가 관행처리구(5,890 kg/10a) 및 대조구(4,473 kg/10a)에 비해 각각 5.7% 및 39.2%의 증수효과를 보였다. 이상의 결과를 미루어 볼 때, 당근 연작재배지에서 녹비작물의 시용은 비료로서 충분한 가치가 있으며, 녹비작물 토양환원 후 토양의 물리성 및 화학성을 개선함으로써 시설하우스 당근 연작재배지의 연작장해를 경감할 수 있을 것으로 사료된다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.351-351
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• 2017

Arbuscular mycorrhizal fungi (AMF) are particular soil fungi that benefit many crops and require a symbiosis with plant roots to survive. In our previous study, there was a positive correlation between AMF root colonization and soybean grain yield in a four-year consecutive winter cover crop-soybean rotational system without phosphorus fertilizer. It is suggested that higher AMF root colonization can be a better solution for improving soybean growth and grain yield in P-limited soil. Our purpose in this study was to test the hypothesis that a P application is the main factor improving soybean growth, P nutrition and grain yield, and the benefit from AMF to soybean P uptake and growth in a P-limited soil. Impact of a P application on AMF root colonization and communities in soybean roots and their potential contribution to soybean growth and P nutrition under a five-year P-unfertilized crop rotational system were investigated over two-years. In this study, four cover crop treatments included 1) wheat (Triticum aestivum); 2) red clover (Trifolium pratense); 3) rapeseed (Brassica napus); and 4) fallow in the crop rotation. The amount of triple superphosphate as a P fertilizer applied rate after cultivation of cover crops was 120 and $360k\;ha^{-1}$ in 2014 and 2015, respectively. Soybean roots were sampled at full-flowering and analyzed for AMF communities using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and quantitative real-time PCR (qPCR) techniques. The AMF root colonization in the soybean roots at full bloom stage was significantly influenced by cover crop and P application throughout the two-year rotation. The two-year rotation of different cover crops or fallow impacted the molecular diversity of AMF communities colonizing roots of soybean. Redundancy analysis (RDA) indicated that AMF communities colonizing roots of soybean were significantly different among cover crop rotations. The AMF communities colonizing roots of soybean were clearly influenced by a P application in the two-year trial. Moreover, a P application may have positively impacts on the AMF communities under P-deficit soil due to the continuous cover crop-soybean rotational system without a P fertilizer.

• 전자공학회논문지T
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• 제36T권1호
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• pp.64-70
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• 1999

본 논문에서는 매니퓰레이터로 작업체 이동시 이동방향 가, 감속에 따른 미끄럼, 회전등의 위치에러 방지를 위한 그리퍼 힘 제어를 작업계획도를 설정해 구간별로 알아본다. 또한 작업체와 매니퓰레이터사이에 가장 정확한 정보를 제공할 수 있는 tactile 센서를 그리퍼에 부착해 연속적으로 tactile 영상 데이터 추론을 통해 미끄럼과 회전을 감지한다. 계산된 파지력과 감지된 에러량 비교를 통해 보상제어와 이를 응용한 최적의 파지력을 구할 수 있다. tactile 센서로는 압각센서인 FSR(Froce Sensing Resistor)을 사용해 22×22 센서회로를 구성하였다. 전처리로써 연속적인 taxel 수를 문턱값으로 설정해 필터링 작업을 하였고, 모멘트 메써드를 감지 알고리즘으로 사용해 실험하였다.

• 대한기계학회논문집A
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• 제29권12권
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• pp.1645-1652
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• 2005

Pick-and-place systems using suction cups have been being widely used and continuously developed in production automation. There are, however, some drawbacks in constructing such systems. One of them is that it generates high level noise due to air compressors. And the system must have complex constitutions of mechanical component such as air compressors, air tubes, air valves, etc. Moreover, it needs continuous air supply to maintain vacuum in suction cups. If there is a failure in any suction cup, the total suction system may fail owing to air leakage. To overcome these drawbacks, we propose PMS (Permanent Magnet Suction) mechanism which has permanent magnets for vacuuming suction cups with no air compressor. The basic concept of PMS mechanism is to rotate permanent magnets with fixed angle. Simple rotation of permanent magnets changes the direction of the magnetic force applied at the suction cups. Since each suction cup has no direct connection with any of the others, the air leakage at one suction cup is not critical. The proposed suction mechanism was designed and fabricated. With some experiments, the feasibility and performance of the PMS mechanism was shown. The strong points of the PMS mechanism are in its simple structure, generating low noise, high energy efficiency, and no need of continuous energy supply.