• Title/Summary/Keyword: STM

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STM Observation of Pt{111}(3$\times$3)-CI and c(4$\times$2)-CI Structures

  • Song, M.B.
    • Bulletin of the Korean Chemical Society
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    • v.22 no.3
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    • pp.267-270
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    • 2001
  • The adsorption of chlorine on a Pt(111) surface at 90 K has been studied using scanning tunneling microscopy (STM) in ultra-high vacuum environments. The adsorbed chlorine atoms give rise to two different ordered structures, (3${\times}$3)-Cl and c(4${\times}$2)- Cl, depending on the coverage. It has been determined from the STM image that the absolute coverage of (3${\times}$3)-Cl structure is 0.44, which is not in agreement with coverage calibrated by a low energy electron diffraction technique together with an Auger electron spectrometer and a thermal desorption spectrometer. The Cl atoms bound to on-top sites at the Pt(111)(3${\times}$3)-Cl surface appeared to effectively perturb the density of states of Pt atoms, as compared with that bound to bridging sites. The other ordered structure, c(4${\times}$2)-Cl, with small domain sizes, consists of both on-top and bridge-bonded species with a saturation coverage of 0.5.

Strength assessment of RC deep beams and corbels

  • Adrija, D.;Geevar, Indu;Menon, Devdas;Prasad, Meher
    • Structural Engineering and Mechanics
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    • v.77 no.2
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    • pp.273-291
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    • 2021
  • The strut-and-tie method (STM) has been widely accepted and used as a rational approach for the design of disturbed regions ('D' regions) of reinforced concrete members such as in corbels and deep beams, where traditional flexure theory does not apply. This paper evaluates the applicability of the equilibrium based STM in strength predictions of deep beams (with rectangular and circular cross-section) and corbels using the available experiments in literature. STM is found to give fairly good results for corbel and deep beams. The failure modes of these deep members are also studied, and an optimum amount of distribution reinforcement is suggested to eliminate the premature diagonal splitting failure. A comparison with existing empirical and semi empirical methods also show that STM gives more reliable results. The nonlinear finite element analysis (NLFEA) of 50 deep beams and 20 corbels could capture the complete behaviour of deep members including crack pattern, failure load and failure load accurately.

Application of a Heat Pack and Soft Tissue Mobilization on Hamstring Muscle of Flexibility in Subjects with Cerebral Palsy (온습포와 연부조직 가동술이 뇌성마비의 슬괵근 유연성 증가에 미치는 영향)

  • Ro, Hyo-Lyun;Lee, Dae-Hee;Kang, Dong-Yeon
    • Journal of the Korean Society of Physical Medicine
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    • v.4 no.3
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    • pp.149-156
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    • 2009
  • Purpose:The hamstring muscle has an important role in standing, walking and other functions related to daily living. Most people with Cerebral Palsy(CP) have muscle tightness, especially in the hamstring, which may cause abnormal alignment in the lower extremities. To investigate an effective treatment for hamstring muscle tightness by observing the effects of heat pack or Soft tissue mobilization(STM) on hamstring muscles. Methods:Thirteen-two volunteers with CP aged between 9 and 13 years($M\pmSD$: $11\pm1.46$), were recruited and divided into four groups of four: (1) the STM for people with Spastic CP group, (2) the heat pack(HP) for people with Spastic CP group, (3) the STM for people with Mixd CP group, and (4) the heat pack for people with Mixed CP group. All received treatment three times per week for six weeks. A inclinometer was used to measure for hip flexion & knee extension joint range motion(ROM). Results:The ROM of hip flexion & knee extension were improved at the STM and HP for people with Spastic CP groups. The ROM and hip flexion were improved at the STM and HP for people with Mixed CP groups. The amount of increase ROM are differenced by the types of CP. Conculusion:STM and heat pack, both are effective for people with CP especially for Spastic CP.

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Hybrid Transactional Memory using Sampling-based Retry Policy in Multi-Core Environment (멀티코어 환경에서 샘플링 기반 재시도 정책을 이용한 하이브리드 트랜잭셔널 메모리)

  • Kang, Moon-Hwan;Jang, Yeon-Woo;Yoon, Min;Chang, Jae-Woo
    • The Journal of Korean Institute of Next Generation Computing
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    • v.13 no.2
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    • pp.49-61
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    • 2017
  • Transactional Memory (TM) has greatly changed the parallel programming paradigm for transaction processing and is classified into STM, HTM, HyTM according to hardware or software frameworks. However, the existing studies have a problem that they provide static retry policy for all workloads. To solve the problems, we propose an hybrid transactional memory scheme using sampling-based adaptive retry policy in multi-core environment. First, the proposed scheme determines whether to use STM or HTM according to the characteristic of a transaction. Otherwise, it executes HTM and STM concurrently by using a bloom filter. Second, the proposed scheme provides adaptive retry policy for HTM according to the characteristic of transactions in each workload. Finally, through the experimental performance evaluation using STAMP, the proposed scheme shows 10~20% better performance than the existing schemes.

Design and Algorithm Implementation of a Distributed Information Retrieval System using Sequential Transferring Method(STM) (순차적 전달방식(STM)을 이용한 분산정보검색시스템의 설계 및 알고리즘 구현)

  • Yoon, Hee-Byung;Kim, Yong-Han;Kim, Hwa-Soo
    • The KIPS Transactions:PartB
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    • v.11B no.5
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    • pp.603-610
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    • 2004
  • The distributed Information Retrieval System centrally controlled by mediator or meta search engine result in congestion of heavy traffic and int he problem of increment of cost for the reason of the design of complicated algorithm for central control and installation of hardware. So to figure out this problem, the way is needed that has independent retrieval functionality and can cooperate each other without dependency. In this paper, we overview a few works involved in distributed information retrieval system, then, implement algorithm and design the frame-work of distributed information retrieval system using sequential transferring method(STM) including multiple information retrieval system separated from central control. For this first of all, we present a web partition policy which devide and manage web logically and we present the sequential query processing way by means of illustration through changing numbered information retrieval system. Then, we also present 3-layered structure of framework and function and module of each layer suitable for information retrieval system. Last of ail, for effective implementation of STM algorithm we analysis module structure and present description of pseudocode of this, and show that the proposed STM algorithm works smoothly by demonstration of sequential query transfer process between servers.

Morphology Observation and Electrical Properties measuring of Self-Assembled Organic Monolayers on Au(111) Substrate Using Scanning Tunneling Microscopy (STM을 이용한 Au(111)기판에 자기조립화된 유기초박막의 모폴로지관찰 및 전기적특성 측정)

  • Lee, Nam-Suk;Shin, Hoon-Kyu;Chang, Jeong-Soo;Kwon, Young-Soo
    • Proceedings of the KIEE Conference
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    • 2004.07c
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    • pp.1715-1717
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    • 2004
  • We attempt to investigate morphology of self-assembled dipyridinium dithioacetate on Au(111) substrate by Scanning Tunneling Microscopy(STM). Also, we measured electrical properties using Scanning Tunneling Spectroscopy(STS). Sample that use this experiment acquires thiol function beside quantity by dipyridinium dithioacetate, is structure that can be self-assembled easily to Au(111) substrate. The same self-assembly procedure was used for two different concentrations, 0.5mmol/ml and 1mmol/ml. Dilute density of sample by 0.5mmol/ml, 1mmol/ml and observed dipyridinium dithioacetate's image by STM after self-assembled on Au(111) substrate. The structure of Tip/SAMs/Au(111) has been used measurement for electrical properties(i-v) using STM. The current-voltage measurement result, observed negative differential resistance(NDR) properties.

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Electron Tunneling and Electrochemical Currents through Interfacial Water Inside an STM Junction

  • Song, Moon-Bong;Jang, Jai-Man;Lee, Chi-Woo
    • Bulletin of the Korean Chemical Society
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    • v.23 no.1
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    • pp.71-74
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    • 2002
  • The apparent barrier height for charge transfer through an interfacial water layer between a Pt/Ir tip and a gold surface has been measured using STM technique. The average thickness of the interfacial water layer inside an STM junction was controlled by the amount of moisture. A thin water layer on the surface was formed when relative humidity was in the range of 10 to 80%. In such a case, electron tunneling through the thin water layer became the majority of charge transfers. The value of the barrier height for the electron tunneling was determined to be 0.95 eV from the current vs. distance curve, which was independent of the tip-sample distance. On the other hand, the apparent barrier height for charge transfer showed a dependence on tip-sample distance in the bias range of 0.1-0.5 V at a relative humidity of approximately 96%. The non-exponentiality for current decay under these conditions has been explained in terms of electron tunneling and electrochemical processes. In addition, the plateau current was observed at a large tip-sample distance, which was caused by electrochemical processes and was dependent on the applied voltage.