• 한국운동역학회지
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• 제19권3호
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• pp.603-610
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• 2009

본 연구의 목적은 드롭 착지 동작 시 탄성 섬유 바지 착용이 충격력과 근육 활동에 어떠한 영향을 미치는가를 분석하는데 있다. 10명의 피험자를 대상으로 7쌍의 표면전극을 대퇴직근, 내측광근, 외측광근, 대퇴이두근, 전경골근, 내측비복근, 외측비복근에 부착하고 탄성 바지와 일반 바지를 무작위로 착용한 상태로 플랫폼에서 드롭 랜딩하였고 각 변인에 대해 대응표본 t-검증을 실시하여 통계적 유의차를 밝혔다(p< .05). 착지 구간 동안 전경골근, 대퇴이두근, 내측비복근의 평균적분 근전도치가 일반바지 착용 시 유의하게 감소되었다. 대퇴직근을 제외한 모든 근육에서 최대적분 근전도가 탄성바지 착용 집단이 높게 나타났다. 탄성바지 착용 시 신체 하지분절의 감속과 안정을 유지하기 위한 근육 동원 능력이 높아져 이러한 현상이 발생되어진 것으로 사료된다. 탄성바지 착용이 충격력과 부하율의 감소에 통계적으로 유의한 결과를 발생시키지 못하였다. 본 연구에서 사용된 탄성바지는 피험자의 하지 둘레에 적합하게 제작되어진 바지가 아니기 때문에 탄성과 압축력이 이상적으로 발생되지 못한 것으로 판단된다.

• 한국운동역학회지
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• 제27권1호
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• pp.35-43
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• 2017

Objective: The purpose of this study was to determine how gaze angle affects muscle activity and kinematic variables during treadmill walking and to offer scientific information for effective and safe treadmill training environment. Method: Ten male subjects who have no musculoskeletal disorder were recruited. Eight pairs of surface electrodes were attached to the right side of the body to monitor the upper trapezius (UT), rectus abdominis (RA), erector spinae (ES), rectus femoris (RF), bicep femoris (BF), tibialis anterior (TA), medialis gastrocnemius (MG), and lateral gastrocnemius (LG). Two digital camcorders were used to obtain 3-D kinematics of the lower extremity. Each subject walked on a treadmill with a TV monitor at three different heights (eye level; EL, 20% above eye level; AE, 20% below eye level; BE) at speed of 5.0 km/h. For each trial being analyzed, five critical instants and four phases were identified from the video recording. For each dependent variable, one-way ANOVA with repeated measures was used to determine whether there were significant differences among three different conditions (p<.05). When a significant difference was found, post hoc analyses were performed using the contrast procedure. Results: This study found that average and peak IEMG values for EL were generally smaller than the corresponding values for AE and BE but the differences were not statically significant. There were also no significant changes in kinematic variables among three different gaze angles. Conclusion: Based on the results of this study, gaze angle does not affect muscle activity and kinematic variables during treadmill walking. However, it is interesting to note that walking with BE may increase the muscle activity of the trapezius and the lower extremity. Moreover, it may hinder proper dorsiflexion during landing phase. Thus, it seems to reasonable to suggest that inappropriate gaze angle should be avoided in treadmill walking. It is obvious that increased walking speed may cause a significant changes in biomechanical parameters used in this study. It is recommended that future studies be conducted which are similar to the present investigation but using different walking speed.

• 한국운동역학회지
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• 제26권1호
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• pp.93-99
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• 2016

Objective: The purpose of this study was to investigate the effect of transcutaneous electrical nerve stimulation (TENS) treatment on maximum voluntary force (MVF) production. Methods: Ten healthy, young subjects (5 males and 5 females) participated in the study. MVF was recorded after a fifteen minute session of TENS stimulation under two conditions: low frequency (4 Hz) at maximum tolerable level and high frequency (110 Hz) at maximum tolerable level. TENS was provided simultaneously via self-adhesive electrodes placed on the finger pads of the index, middle, ring and little fingers. MVF was also recorded in a baseline condition with no TENS treatment. Data were collected in three different sessions on three consecutive days at the sametime of the day. Results: Results from the study show that on an average, MVF increasesby 25% for the index, middle and little fingers for TENS treatment with 4 Hz frequency as compared to the baseline condition. However, the 110 Hz condition did not result in a significantly different MVF than the baseline condition during individual finger pressing tasks. In addition, while producing MVF with all the four finger stogether, MVF was 30% higher for the 4 Hz conditionin comparison to the baseline condition, and 15% higher for the 110 Hz condition in comparison to the baseline condition respectively. Conclusion: The results suggest that stimulation ofafferent fibers onthe glabrous skinwith TENS could have a net facilitatory effect on the maximum motoroutput.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.68-69
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• 2011

The process of charge transfer at the interface between two semiconductors or between a metal and a semiconductor plays an important role in many areas of technology. The optimization of such devices requires a good theoretical description of the interfaces involved. This, in turn, has motivated detailed mechanistic studies of interfacial charge-transfer reactions at metal/organic, organic/organic, and organic/inorganic semiconductor heterojunctions. Charge recombination of photo-induced electron with redox species such as oxidized dyes or triiodide or cationic HTM (hole transporting materials) at the heterogeneous interface of $TiO_2$ is one of main loss factors in liquid junction DSSCs or solid-state DSSCs, respectively. Among the attempts to prevent recombination reactions such as insulating thin layer and lithium ions-doped hole transport materials and introduction of co-adsorbents, although co-adsorbents retard the recombination reactions as hydrophobic energy barriers, little attention has been focused on the anchoring processes. Molecular engineering of heterogeneous interfaces by employing several co-adsorbents with different properties altered the surface properties of $TiO_2$ electrodes, resulting to the improved power conversion efficiency and long-term stability of the DSSCs. In this talk, advantages of the coadsorbent-assisted sensitization of N719 in preparation of DSSCs will be discussed.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.333-333
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• 2011

We have investigated the breakdown properties in liquids by high voltage pulse system. High voltage pulse power system is consisted of the Marx-generator with two capacitors (0.5 ${\mu}F$, withstanding voltage is 40 kV), to which the charging voltage can be applied to maximum 30 kV DC, spark gap switch and charging resistor of 20 $M{\Omega}$. We have made use of tungsten pin electrodes of anode-cathode (A-K), which are immersed into the liquids. The breakdown voltage and current signals are measured by high voltage probe (Tektronix P6015A) and current monitor (IPC CM-1.S). Especially the high speed breakdown or plasma propagation characteristics in the pulsed A-K gap have been investigated by using the high speed ICCD camera. We have measured the electron temperature through the Boltzmann plot method from the breakdown spectrums. Here the A-K gap has been changed by 1 mm, 2 mm, and 3 mm. The used liquids are distilled water and solution of salt (0.9 %). The output voltage and current signals at breakdown in distilled water are shown to be bigger than those in saline solution. The breakdown voltage and current characteristics in liquids will be discussed in accordance with A-K gap distances. It is also found that the electron temperatures and plasma densities in liquids are decreased in conformity with A-K gap.

• 분석과학
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• 제17권3호
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• pp.217-224
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• 2004

소형의 이온선택성 전극을 흐름계 어레이로 구성하여 전자혀 시스템을 제작하였다. 제작된 전자혀 시스템에 음용수 및 알코올성 음료를 저 농도의 완충용액 (0.005 M Tris-$H_2SO_4$ pH 7.2)에 묽힌 후 9개의 전극이 장착된 흐름계에 흘려 보내어 전위차를 측정하였다. 얻어진 자료는 주성분 분석 (principal component analysis; PCA)을 통하여 식음료의 맛을 평가할 수 있도록 2차원 및 3차원 좌표계에 표시하였다. 본 연구에서 제작한 전자혀 시스템은 식품의 생산공정관리의 목적으로 또는 시중에서 구할 수 있는 식음료 맛의 변화 추이를 구분해 내는 목적으로 유용하게 사용될 수 있다.

• 한국염색가공학회지
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• 제6권3호
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• pp.27-36
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• 1994

In order to produce a water repellent surface on polyester fabric, samples were treated in the atmosphere of $CF_4$ glow discharge plasma. The samples used in the study were ployester fabric and poyester film. The purpose of film treatment is for the comparison of hydrophobicity with fabric sample at same treatment condition. Radio frequency(13.56MHz) generator was used as electric source and its in put power is 100 Watt. Water repellency was evaluated by contact angle measurement. Result obtained are as follows. 1) Fiber interstice of original fabric was ana lysed as 0.43$\mu$m, and this value was sufficiently ideal for making water repellent fabric. 2) The most favorable setting position of substrate was the center area between two electrodes. 3) Fabric contact angle was higher than film contact angle at same treatment condition, and its difference was more than 50${\circ}$. And it was incapalbe of fabric contact angle measurement when the film contact angle was less than 90${\circ}$. because the fabric is susceptible to absorption of water by the capillary effect. 4) Fabric contact angle can not revealed the precise defferences of surface hydrophobicity, however, the film contact angle showed the real hydrophobic nature. 5) It was not sufficient method to evaluate the hydrophobicity of fabric surface by merely measure of the water contact angle. 6) It showed high water repellent nature at 0.06 torr of $CF_4$ plasma gas pressure and duration of 45 seconds treatment, and it can not be anticipated more improved nature if the pressure and duration of treatment time were increased.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2018년도 춘계학술대회 논문집
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• pp.67-67
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• 2018

The 5xxx series aluminum alloys are recently used in not only marine system but also automotive area because of a low density material, good mechanical properties and better resistance to corrosion. However, Aluminum alloys are less resistant than the purest aluminum such as 1xxx aluminum alloy. Electrochemical anodization technique has attracted in the area of surface treatment because of a simple procedure, a low-cost efficiency than other techniques such as lithography and a large volume of productivity, and so on. Here, The relationship between the corrosion behavior and the thickness of aluminum anodic oxide have been studied. Prior to anodization, The 5052 aluminum sheets ($30{\times}20{\times}1mm$) were degreased by ultra-sonication in acetone and ethanol for 10 minutes and eletropolished in a mixture of perchloric acid and ethanol (1:4, volume ratio) under an applied potential of 20V for 60 seconds to obtain a regular surface. During anodization process, Aluminum alloy was used as a working electrode and a platinum was used as a counter electrode. The two electrodes were separated at a distance of 5cm. The applied voltage of anodization is conducted at 40V in a 0.3M oxalic acid solution at $0^{\circ}C$ with appropriate magnetic stirring. The surface morphology and the thickness of AAO films was observed with a Scanning Electron Microscopy (SEM). The corrosion behavior of all samples was evaluated by an open-circuit potential and potentio-dynamic polarization test in 3.5wt% NaCl solution. Thus, The corrosion resistance of 5052 aluminum alloy is improved by the formation of an anodized oxide film as function of increase anodization time which artificially develops on the metal surface. The detailed electrochemical behavior of aluminum 5052 alloy will be discussed in view of the surface structures modified by anodization conditions such as applied voltages, concentration of electrolyte, and temperature of electrolyte.

• 분석과학
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• 제23권2호
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• pp.165-171
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• 2010

글루코스 옥시다아(GOx)제 고정화 바이오센서를 두 가지 방법으로 제조 하였다. 첫 번째 방법은 폴리(maleic anhydride) 그래프트 탄소나노튜브(PMAn-g-MWCNT) 전극에 감마선 조사법으로 제조 된 Au 나노입자를 물리적으로 흡착시킨 후, GOx을 고정화 시켜 바이오센서를 제조한 경우이고, 다른 하나는 PMAn-g-MWCNT 전극에서 Au 이온을 전기화학적으로 환원시켜 Au 나노입자를 코팅 시키고, 그 위에 GOx을 고정화 시켜 바이오센서를 제조 한 경우이두. 제조된 바이오센서에 대해 효율 평가를 수행 하였는데, 물리적 흡착법으로 제조된 전극의 경우 검출 범위는 $30\;{\mu}M\sim100\;{\mu}M$이었으며, 검출한계는 $15\;{\mu}M$이었다. 또한 ascorbic acid와 uric acid에 대한 검출한계는 7.6%이었다. 물리적으로 Au 나노입자가 흡착된 전극의 경우가 글루코스 측정에 매우 우수한 전극임을 확인 하였다.

• 원예과학기술지
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• 제32권5호
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• pp.710-720
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• 2014

Movements of the upper and lower limb muscles during five common gardening tasks were analyzed by using electromyography (EMG). Twenty adults aged in their twenties (mean age, $24.8{\pm}2.4$ years) were recruited. On two separate occasions, subjects visited a garden plot to perform digging, raking, troweling, weeding, and hoeing; all tasks were performed three times with 20 s intervals for each trial. To measure muscle activation during the five gardening tasks, surface EMG was used. Bipolar surface EMG electrodes were attached to eight upper limb muscles (bilateral anterior deltoid, biceps brachialis, brachioradialis, and flexor carpi ulnaris) or eight lower limb muscles (bilateral vastus lateralis, vastus medialis, biceps femoris, and gastrocnemius) on both sides of the body, for a total of 16 muscles. During the five tasks, photographs were taken of movement phases using a digital video camera. The right flexor carpi ulnaris and brachioradialis showed higher activation than the other upper and lower limb muscles measured during the tasks. All 16 upper and lower limb muscles were actively used only during digging. According to movement analysis of each activity, digging was classified into four movement phases, whereas raking, troweling, weeding, and hoeing each were divided into three movement phases. In each activity, there were high-impact phases in terms of muscle activation; the flexor carpi ulnaris and brachioradialis were identified as major muscles in each impact phase. This analysis may be used to generate biomechanical profiles of gardening tasks for practitioners when designing efficient gardening interventions for physical health or rehabilitation.