• Title, Summary, Keyword: V-cut

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A Case Study of the New Center-Cut Method in Tunnel : SAV-Cut(Stage Advance V-Cut) (터널 심발발파공법 SAV-Cut(Stage Advance V-Cut)의 특징 및 현장적용 사례 연구)

  • Kim, Dong-Hyun;Lee, Sang-Pil;Lee, Hun-Yeon;Lee, Tae-Ro;Jeon, Seok-Won
    • Explosives and Blasting
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    • v.25 no.1
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    • pp.31-43
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    • 2007
  • In most tunnel constructions in South Korea, blasting has been widely used as an excavation method. In tunnel blasting, the center-cut to induce first free surface is very important for enhancing excavation efficiency and reducing vibration caused by exploding. This paper introduces new center-cut method named SAV-cut (Stage Advance V-cut) developed on the concept of V-cut. Significant features of SAV-cut are the center hole and stepwise ignition. Many field tests and numerical analysis were carried out to analyze the mechanical behavior and blasting vibration. From the results, the newly developed SAV-cut was proved as an effective center-cut method for both increasing blasting efficiency and decreasing blasting vibration.

The Method of Tunnel Blasting for the Vibration Control by Deck Charge and Multiple Cut (다단장약에 의한 V-cut 발파공법의 진동제어효과와 발파효율증대에 관한 연구)

  • 두준기;양형식;김형건;김용국
    • Explosives and Blasting
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    • v.21 no.3
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    • pp.1-10
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    • 2003
  • 터널굴착발파공법의 하나인 V-cut발파공법은 터널굴착기술이 발전되는 과정에서 초기에 개발되어진 기술이나 작업의 간편성과 효율성으로 인하여 많은 터널굴착공사에서 이용되고 있는 발파공법이다. V-cut발파공법은 일자유면 상태에서 V형으로 심발공을 발파하고 심발공에 의해 형성된 자유면을 이용하여 확대공으로 굴착공간을 넓히는 발파 방법이며 심발발파의 굴진장에 의해 단일발파당 굴진장이 결정된다. V-cut발파법이 개발된 이래 V-cut발파의 굴진장을 증대시키기 위한 방법으로 심발발파공의 구속저항을 감소시키기 위해 보조심발공을 발파하여 형성된 자유면에 의해 심발공의 최소저항선거리를 줄여 발파하였으나 심발공의 구속저항이 감소되지 않아 발파효율이 증대되지 않았으며 발파진동 또한 가장 크게 발생하였다. 이와 같은 현상은 최소저항선거리의 감소효과에 대한 발파기술상의 이론에 문제가 있기 때문이다. 본 연구에서는 V-cut발파법의 심발공에 대한 구속저항감소효과가 발현될 수 있는 조건들을 검토하여 최소저항선거리의 감소효과가 발현될 수 있는 조건을 제시 하여 심발공의 발파효율을 증대시키고 발파진동이 적어지는 발파방법을 제안하려 한다.

Fabrication and Frequency Agile of Microstrip Antennas Using Y-cut $LiNbo_3$, Quartz and FR-4 Substrates. (Y-cut $LiNbo_3$, Quartz, FR-4 기판을 이용한 마이크로스트립 안테나의 제작과 공진주파수 이동에 관한 연구.)

  • Lee, Ki-Se;Lee, Kyu-Il;Kang, Hyun-Il;Song, Joon-Tae
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.116-120
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    • 2004
  • In this paper, we proposed a method to shift the resonant frequency by applying the electric field to microstrip patch antenna using piezoelectric substrates. We fabricated microstrip patch antenna using Y-cut LiNbO3, Quartz and FR-4 substrates. We designed and simulated the microstrip antennas by Ensemble V 7.0 of the simulation too1. We observed the resonant frequency by DC applied electric field in a microstrip patch antenna. When the electric field was 300 V/mm, the resonant frequency agile of Y-cut LiNbO3 microstrip patch antennas were 29 MHz. When the electric field was 400 V/mm, the frequency agile of X-cut, Y-cut and Z-cut quartz microstrip patch antennas were 55.2 MHz, 34.2 MHz and 28.0 MHz, respectively. However, when the electric field was 400 V/mm, the resonant frequency of FR-4 microstrip patch antenna does not changed. It was shown that the resonant frequency agile of Y-cut and Z-cut quartz microstrip patch antennas are due to piezoelectric phenomenon not to be permittivity.

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A Study on Effective Source-Skin Distance using Phantom in Electron Beam Therapy

  • Kim, Min-Tae;Lee, Hae-Kag;Heo, Yeong-Cheol;Cho, Jae-Hwan
    • Journal of Magnetics
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    • v.19 no.1
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    • pp.15-19
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    • 2014
  • In this study, for 6-20 MeV electron beam energy occurring in a linear accelerator, the authors attempted to investigate the relation between the effective source-skin distance and the relation between the radiation field and the effective source-skin distance. The equipment used included a 6-20 MeV electron beam from a linear accelerator, and the distance was measured by a ionization chamber targeting the solid phantom. The measurement method for the effective source-skin distance according to the size of the radiation field changes the source-skin distance (100, 105, 110, 115 cm) for the electron beam energy (6, 9, 12, 16, 20 MeV). The effective source-skin distance was measured using the method proposed by Faiz Khan, measuring the dose according to each radiation field ($6{\times}6$, $10{\times}10$, $15{\times}150$, $20{\times}20cm^2$) at the maximum dose depth (1.3, 2.05, 2.7, 2.45, 1.8 cm, respectively) of each energy. In addition, the effective source-skin distance when cut-out blocks ($6{\times}6$, $10{\times}10$, $15{\times}15cm^2$) were used and the effective source-skin distance when they were not used, was measured and compared. The research results showed that the effective source-skin distance was increased according to the increase of the radiation field at the same amount of energy. In addition, the minimum distance was 60.4 cm when the 6 MeV electron beams were used with $6{\times}6$ cut-out blocks and the maximum distance was 87.2 cm when the 6 MeV electron beams were used with $20{\times}20$ cut-out blocks; thus, the largest difference between both of these was 26.8 cm. When comparing the before and after the using the $6{\times}6$ cut-out block, the difference between both was 8.2 cm in 6 MeV electron beam energy and was 2.1 cm in 20 MeV. Thus, the results showed that the difference was reduced according to an increase in the energy. In addition, in the comparative experiments performed by changing the size of the cut-out block at 6 MeV, the results showed that the source-skin distance was 8.2 cm when the size of the cut-out block was $6{\times}6$, 2.5 cm when the size of the cut-out block was $10{\times}10$, and 21.4 cm when the size of the cut-out block $15{\times}15$. In conclusion, it is recommended that the actual measurement is used for each energy and radiation field in the clinical dose measurement and for the measurement of the effective source-skin distance using cut-out blocks.

Quartz를 이용한 마이크로스트립저역필터 특성에 관한 연구

  • U, Hyeong-Gwan;Kim, Eung-Gwon;Song, Jun-Tae
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.136-136
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    • 2009
  • It is investigated the cut-off frequency of Z-cut quartz microstrip low pass filter by the variation of applied electric field. Designed microstrip filter was simulated using the Ensemble v7.0(Ansoft). As a result of the experiment, the cut-off frequency showed 50 MHz shift when the applied electric field was 3 kV/cm.

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Charge-discharge Properties by Cut-off Voltage Changes of Li(${Mn_{1-\delta}}{M_{\delta}$)$_2$$O_4$ and ${LiMn_2}{O_4}$in Li-ion Secondary Batteries (코발트와 니켈로 치환한 리튬이온 이차전지 Cathode, Li(${Mn_{1-\delta}}{M_{\delta}$)$_2$$O_4$${LiMn_2}{O_4}$의 Cut-off 전압 변화에 따른 충방전 특성)

  • 유광수;박재홍;이승원;조병원
    • Journal of the Korean Ceramic Society
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    • v.38 no.5
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    • pp.424-430
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    • 2001
  • Cut-off 전압 변화에 따른 충방전 특성을 알아보기 위하여 Mn을 다른 전이 금속이 Co와 Ni로 소량 치환시킨 Li(M $n_{1-{\delta}}$ $n_{\delta}$)$_2$ $O_4$(M=Ni, Co, $\delta$=0, 0.05, 0.1, 0.2)를 고상 반응법으로 80$0^{\circ}C$에서 48시간 동안 유지하여 합성하였다. 충방전의 cut-off 전압은 2.5~4.4V, 3.0~4.5V, 3.5~4.5V, 3.5V~4.7V의 네 가지 전압범위고 하였다. 충방전 실험결과, Li(M $n_{1-{\delta}}$ $n_{\delta}$)$_2$ $O_4$의 용량은 각각 Co와 Ni의 $\delta$=0.1에서 최대를 보였다. Co 치환 조성 재료와 순물질 모두에서 최대의 용량을 보인 cut-off 전압대는 3.5~4.5V 이었는데 이때의 Li(M $n_{0.9}$ $Co_{0.1}$)$_2$ $O_4$와 LiM $n_2$ $O_4$의 초기 충전용량과 초기 방전용량은 각각 118, 119mAh/g과 114, 104mAh/g 이었다. 또한 모든 cut-off 전압대에서 Li(M $n_{0.9}$ $Co_{0.1}$)$_2$ $O_4$는 순수한 LiM $n_2$ $O_4$보다 더 높은 용량과 우수한 싸이클 성능을 보였으며 그 결과는 밀착형 전지구성에서도 일치하였다.하였다.

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A Minimum Cut Algorithm Using Maximum Adjacency Merging Method of Undirected Graph (무방향 그래프의 최대인접병합 방법을 적용한 최소절단 알고리즘)

  • Choi, Myeong-Bok;Lee, Sang-Un
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.13 no.1
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    • pp.143-152
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    • 2013
  • Given weighted graph G=(V,E), n=|V|, m=|E|, the minimum cut problem is classified with source s and sink t or without s and t. Given undirected weighted graph without s and t, Stoer-Wagner algorithm is most popular. This algorithm fixes arbitrary vertex, and arranges maximum adjacency (MA)-ordering. In the last, the sum of weights of the incident edges for last ordered vertex is computed by cut value, and the last 2 vertices are merged. Therefore, this algorithm runs $\frac{n(n-1)}{2}$ times. Given graph with s and t, Ford-Fulkerson algorithm determines the bottleneck edges in the arbitrary augmenting path from s to t. If the augmenting path is no more exist, we determine the minimum cut value by combine the all of the bottleneck edges. This paper suggests minimum cut algorithm for undirected weighted graph with s and t. This algorithm suggests MA-merging and computes cut value simultaneously. This algorithm runs n-1 times and successfully divides V into disjoint S and V sets on the basis of minimum cut, but the Stoer-Wagner is fails sometimes. The proposed algorithm runs more than Ford-Fulkerson algorithm, but finds the minimum cut value within n-1 processing times.

Development and evaluation of new drilling and blasting method for excavaton of rock mass with one free surface (일자유면 암반 굴착을 위한 신바파공법의 개발 및 평가)

  • 임재웅;윤영재;서정복
    • Tunnel and Underground Space
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    • v.4 no.3
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    • pp.237-249
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    • 1994
  • A new type of cut method, called SK-cut, was developed in order to overcome the shortcomings of the conventional V-cut and Burn-cut blasting methods. Total 190 times of test blasts were performed for the evaluation of the efficiency of new blasting method. V-cut, Burn cut and SK-cut were compared by applying them to the excavation of main gallery and construction tunnel of underground oil storage cavern. Test results showed that excavation efficiency of the new method was increased by 5.9~9.8% and that specific charge was reduced to 71~92%.

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Anatomy of Spleen Meridian Muscle in human (족태음비경근(足太陰脾經筋)의 해부학적(解剖學的) 고찰(考察))

  • Park Kyoung-Sik
    • Korean Journal of Acupuncture
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    • v.20 no.4
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    • pp.65-75
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    • 2003
  • This study was carried to identify the component of Spleen Meridian Muscle in human, dividing into outer, middle, and inner part. Lower extremity and trunk were opened widely to demonstrate muscles, nerve, blood vessels and the others, displaying the inner structure of Spleen Meridian Muscle. We obtained the results as follows; 1. Spleen Meridian Muscle is composed of the muscle, nerve and blood vessels. 2. In human anatomy, it is present the difference between a term of nerve or blood vessels which control the muscle of Meridian Muscle and those which pass near by Meridian Muscle. 3. The inner composition of meridian muscle in human arm is as follows ; 1) Muscle; ext. hallucis longus tend., flex. hallucis longus tend.(Sp-1), abd. hallucis tend., flex. hallucis brevis tend., flex. hallucis longus tend.(Sp-2, 3), ant. tibial m. tend., abd. hallucis, flex. hallucis longus tend.(Sp-4), flex. retinaculum, ant. tibiotalar lig.(Sp-5), flex. digitorum longus m., tibialis post. m.(Sp-6), soleus m., flex. digitorum longus m., tibialis post. m.(Sp-7, 8), gastrocnemius m., soleus m.(Sp-9), vastus medialis m.(Sp-10), sartorius m., vastus medialis m., add. longus m.(Sp-11), inguinal lig., iliopsoas m.(Sp-12), ext. abdominal oblique m. aponeurosis, int. abd. ob. m., transversus abd. m.(Sp-13, 14, 15, 16), ant. serratus m., intercostalis m.(Sp-17), pectoralis major m., pectoralis minor m., intercostalis m.(Sp-18, 19, 20), ant. serratus m., intercostalis m.(Sp-21) 2) Nerve; deep peroneal n. br.(Sp-1), med. plantar br. of post. tibial n.(Sp-2, 3, 4), saphenous n., deep peroneal n. br.(Sp-5), sural cutan. n., tibial. n.(Sp-6, 7, 8), tibial. n.(Sp-9), saphenous br. of femoral n.(Sp-10, 11), femoral n.(Sp-12), subcostal n. cut. br., iliohypogastric n., genitofemoral. n.(Sp-13), 11th. intercostal n. and its cut. br.(Sp-14), 10th. intercostal n. and its cut. br.(Sp-15), long thoracic n. br., 8th. intercostal n. and its cut. br.(Sp-16), long thoracic n. br., 5th. intercostal n. and its cut. br.(Sp-17), long thoracic n. br., 4th. intercostal n. and its cut. br.(Sp-18), long thoracic n. br., 3th. intercostal n. and its cut. br.(Sp-19), long thoracic n. br., 2th. intercostal n. and its cut. br.(Sp-20), long thoracic n. br., 6th. intercostal n. and its cut. br.(Sp-21) 3) Blood vessels; digital a. br. of dorsalis pedis a., post. tibial a. br.(Sp-1), med. plantar br. of post. tibial a.(Sp-2, 3, 4), saphenous vein, Ant. Med. malleolar a.(Sp-5), small saphenous v. br., post. tibial a.(Sp-6, 7), small saphenous v. br., post. tibial a., peroneal a.(Sp-8), post. tibial a.(Sp-9), long saphenose v. br., saphenous br. of femoral a.(Sp-10), deep femoral a. br.(Sp-11), femoral a.(Sp-12), supf. thoracoepigastric v., musculophrenic a.(Sp-16), thoracoepigastric v., lat. thoracic a. and v., 5th epigastric v., deep circumflex iliac a.(Sp-13, 14), supf. epigastric v., subcostal a., lumbar a.(Sp-15), intercostal a. v.(Sp-17), lat. thoracic a. and v., 4th intercostal a. v.(Sp-18), lat. thoracic a. and v., 3th intercostal a. v., axillary v. br.(Sp-19), lat. thoracic a. and v., 2th intercostal a. v., axillary v. br.(Sp-20), thoracoepigastric v., subscapular a. br., 6th intercostal a. v.(Sp-21)

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Charge/discharge Capacity of Natural Graphite Anode According to the Charge/discharge Rate in Lithium Secondary Batteries (리튬 이차전지의 음극재료인 천연흑연의 충방전 속도에 따른 충방전 용량)

  • Ryu Ji Heon;Oh Eun Young;Oh Seung M.
    • Journal of the Korean Electrochemical Society
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    • v.7 no.1
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    • pp.32-37
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    • 2004
  • The charge/discharge capacity of natural graphite anode in lithium secondary batteries was examined as a function of charge/discharge rate. When the natural graphite anode was galvanostatically cycled in the range of 0.0-2.0V $(vs.\;Li/Li^+)$, the charging capacity decreased with an increase in the charging rate, which is caused by an earlier approach to the charging cut-off (0.0 V) before the complete charging that is in turn caused by an ever-increasing overpotential at higher rates. Even if the overpotential of discharging reaction also increased at higher discharge rates, the discharging reaction took place in the range of 0.0-0.3 V that is far below the discharge cut-off (2.0 V). As a result, the discharge capacity was not affected by the discharge rate because all the lithium ions once intercalated are fully discharged even at high current condition. As the overpotential of lithium deposition reaction also increased at high current condition, the charge capacity of natural graphite could be enlarged by lowering the charging cut-off voltage below 0.0 V, There is, however, a limitation for the lowering of cut-off voltage because the resistance for lithium deposition is smaller than that of lithium intercalation into graphite. When the charge cut-off voltage was lowered down to -0.04 V under IC condition, lithium ions were inserted into graphite without lithium deposition such that the discharge capacity could be raised up to $11\%$.