• Title/Summary/Keyword: Volume effect

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Temperature Measurement in Concentric Diffusion Flames by Rapid Insertion Technique (급속 삽입법에 의한 화염 내부 온도 분포 측정)

  • Lee, Gyo-Woo;Chung, Young-Rok;Jurng, Jong-Soo
    • Journal of the Korean Society of Combustion
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    • v.4 no.2
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    • pp.75-83
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    • 1999
  • The effect of temperature distributions on soot volume fraction in double-concentric diffusion flames have been investigated experimentally. Using fine thermocouple wires and a rapid insertion mechanism, we have measured temperature without the effect of soot particles attached to the thermocouple junction, which can lower the temperature signal about 100 K by increasing the heat loss from the junction by radiation. The temperature at the flame axis is higher in the double-concentric diffusion flames than in normal co-flow diffusion flames because of the inverse diffusion flame. However, it is almost the same as that at the periphery of normal flames, on which the inverse flame does not have an effect. Thus, the lower soot concentration found in the double-concentric diffusion flame can be explained by the effect of nitrogen diffusion from the central air jet.

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Promotion or Prevention? The Moderating Effect of Embedded External Reviews on Consumer Evaluations

  • Ziqiong Zhang;Le Wang;Shuchen Qiao;Zili Zhang
    • Journal of Smart Tourism
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    • v.3 no.3
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    • pp.5-15
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    • 2023
  • Given the increasing information overload among users of online review websites, understanding the manner in which cognitive costs are reduced and efficient information is made reliable has become increasingly important. This study targets a unique consumer review design and explores how reviews from an external peer-to-peer site embedded in an online travel agency (OTA) website influence subsequent evaluation behaviors. The empirical results indicate that (1) embedded external reviews with a high average valence tend to strengthen the influence of the positive evaluation ratio while diminishing the effect of the review volume, and (2) embedded external reviews with a large variance strengthen the positive effect of the review volume while weakening the effect of the positive evaluation ratio on subsequent positive evaluations. The findings provide practical insights for consumers and online platforms.

The Effects of Microstructure in Austenitic 316L Stainless Steels on the Strength and Damping Capacity (오스테나이트계 316L 스테인리스강의 강도 및 감쇠능에 미치는 미세조직의 영향)

  • SON DONG-WOOK;LEE JONG-MOON;KIM HYO-JONG;NAM KI-WOO;PARK KYU-SEOP;KANG CHANG-YONG
    • Journal of Ocean Engineering and Technology
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    • v.20 no.1 s.68
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    • pp.1-6
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    • 2006
  • The effects of microstructure on the damping capacity and tensile properties of 316L stainless steel were investigated. Increasing the degree of cold working, the volume fraction of $\varepsilon-martensite$ decreased after rising to maximum value at specific level of cold working, the volume fraction of d-martensite slowly increased and then dramatically increased from the point of decreasing $\varepsilon-martensite$ volume fraction. Increasing the degree of cold working, the behnvior of damping capacity is similar to that of the $\varepsilon-martensite$. After the damping capacity showing the maximum value at about $20\%$ of cold rolling, damping capacity was decreased with the volume fraction of $\varepsilon-martensite$. Tensile strength was proportional to the volume fraction of d-martensite, and elongation steeply decreased in the range low volume fraction of a'-martensite, then slowly decreased in range the above $10\%$ volume fraction of d-martensite. The damping capacity and elongation is strongly controlled by the volume fraction of $\varepsilon$ martensite with liner relationship. However, the effect of the volume fraction of d-martensite and austenite phase on the damping capacity was not observed. Tensile strength was governed by the volume fraction of d-martensite.

Packing effects on the intracavitary radiation Therapy 3-Dimension plan of the uterine cervix cancer (자궁경부암 강내조사 3차원 치료계획 시 Packing의 유용성 분석)

  • Si, Chang-Keun;Jo, Jung-Kun;Lee, Du-Hyun;Kim, Sun-Yeung;Kim, Tae-Yoon
    • The Journal of Korean Society for Radiation Therapy
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    • v.17 no.1
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    • pp.1-8
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    • 2005
  • Purpose : An effect of a packing to uterine treatment of a cervical cancer using a dose-volume histogram for a point dose and a volume dose of the bladder and the rectum was analyzed by establishing a three-dimensional treatment plan using a CT image. Materials and methods : Reference points of the bladder and the rectum were marked, respectively at a treatment plan device (plato brachytherapy V14.2.4) by photographing CT(marconi, USA) when the packing was used and removed under the same condition and a treatment plan was performed to Apoint depending on ICRU38. However, in case of the rectum, a maximum point was looked up and compared with the above point because the point presented from the ICRU is not proper as a representative value of a rectum point dose. Further, the volume dose depending on volume of $50\%,\;80\%,\;and\;100\%$ point doses of the rectum and the bladder was measured. The measured values were used to analyze the effect of the packing through a Wilcoxon Signed Rank Test (a SAS statistical analysis process program). Result : The reference points at the bladder and rectum doses when the packing was removed were $116.94\;35.42\%$ and $117.59\;21.08\%$, respectively. The points when the packing was used were $107.08\;38.12\%$ and $95.19\;21.32\%$, respectively. After the packing was used, the reference points at the bladder and the rectum were decreased by $9.86\%$ and $22.4\%$, respectively. When the packing was removed, the maximum points at the bladder and the rectum were $164.51\;50.89\%,\;128.81\;33.05\%$, respectively. When the packing was used, the maximum points at the bladder and the rectum were $142.31\;44.79,\;110.08\;37.03\%$, respectively. After the packing was used, the maximum points at the bladder and the rectum were decreased by $22.2\%$ and $18.73\%$, respectively. When the packing was removed, the bladder volume at $50\%,\;80\%,\;and\;100\%$ point doses of the rectum and the bladder were $48.62{\pm}18.09\%,\;16.12{\pm}11.15\%,\;and\;7.51{\pm}6.63\%$, respectively and its rectum volume were $23.41{\pm}14.44\%,\;6.27{\pm}4.28\%,\;2.79{\pm}2.27\%$, respectively. When the packing was used, the bladder volume at $50\%,\;80\%,\;and\;100\%$ point doses of the rectum and the bladder were $40.33{\pm}16.72,\;11.63{\pm}8.72,\;and\;4.87{\pm}4.75\%$, respectively and its rectum volume were $18.96{\pm}8.37\%,\;4.75{\pm}2.58\%,\;and\;1.58{\pm}1.06\%$, respectively. After the packing was used, the bladder volume at $50\%,\;80\%,\;and\;100\%$ point doses of the rectum and the bladder were decreased by $8.29\%,\;4.49\%,\;and\;2.64\%$, respectively and its bladder volume were decreased by $4.45\%,\;1.52\%,\;and\;1.21\%$, respectively. Conclusion : Values at Reference point doses of the bladder and the rectum recommended from the ICRU 38 were 0.0781 and 0.0781, respectively and values of their maximum point doses were 0.0156 and 0.0156, respectively, as a result of which an effect of the packing using at the uterine intracavitary treatment of an uterine cervical cancer through the three-dimensional treatment plan used CT were measured. That is, the values at reference point doses and the values at maximum point doses show similar difference. However, P value was 0.15 at over $50\%,\;80\%,\;and\;100\%$ volume doses and the value shows no similar difference. In other words, the effect of the packing looks like having a difference at the point dose, but actually shows no difference at the volume dose. The reason is that the volume of the bladder and the rectum are wide but the volume of the packing is only a portion. Therefore, the effect of decreasing the point dose was not great. Further, the farer the distance is, the more weak the intensity of radiation is because the intensity of radiation is proportional to inverse square of a distance. Therefore, the effort to minimize an obstacle of the bladder and the rectum by using the packing should be made.

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Mechanical behavior of hybrid steel-PVA fibers reinforced reactive powder concrete

  • Poorhoseina, Reza;Nematzadeh, Mahdi
    • Computers and Concrete
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    • v.21 no.2
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    • pp.167-179
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    • 2018
  • Reactive powder concrete (RPC) is a type of ultra-high strength cement-based material with a dense microstructure, which is made of ultra-fine powders. RPC demonstrate a very brittle behavior, thus adding fibers improves its mechanical properties. In this study, it was attempted to investigate the effect of using steel and polyvinyl alcohol (PVA) fibers as well as their combination on the properties of RPC. In this regard, hooked-end crimped steel fibers together with short PVA fibers were utilized. Steel and PVA fibers were used with the maximum volume fraction of 3% and 0.75%, respectively, and also different combinations of these fibers were used with the maximum volume fraction of 1% in the concrete mixes. In total, 107 concrete specimens were prepared, and the effect of fiber type and volume fraction on the physico-mechanical properties of RPC including compressive strength, tensile strength, modulus of elasticity, density, and failure mode was explored. In addition, the effect of the curing type on the properties of compressive strength, modulus of elasticity, and density of RPC was evaluated. Finally, coefficients for conversion of cubic compressive strength to cylindrical one for the RPC specimens were obtained under the two curing regimes of heat treatment and standard water curing.

Neuroprotective Effect of Semen Persicae in Middle Cerebral Artery Occlusion Rats (도인(桃仁)의 중대뇌동맥 폐색 유발 흰쥐에서 신경보호 효과)

  • Song, Mi-Young;Kim, Ho-Jun;Lee, Myeong-Jong
    • The Journal of Korean Medicine
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    • v.30 no.2
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    • pp.117-126
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    • 2009
  • Objectives: This study was performed to investigate the effects of Semen Persicae (SP) on infarct volume, COX-2 protein expression in the middle cerebral artery occlusion (MCAo) rats. Methods: Twenty-eight rats were randomly assigned to four groups (MCAo experimental group, MCAo control group, sham experimental group, control group). The middle cerebral artery (MCA) was occluded in the MCAo group by proximal focal cerebral ischemia rat model, while the MCA was not occluded in the sham group. SP extraction was administrated for 4 days to each experimental group. Neuroprotective effects were investigated by measurement of brain damage using 2, 3, 5-triphenyltetrazolium chloride staining and analysis of COX-2 protein expression by western blotting. Results: The occurrence of infarct volume in the SP oral administration group decreased compared to the control group. COX-2 protein expression in the SP oral administration group decreased compared to the control group. Conclusions: The present study demonstrates the effect of SP in reducing infarct volume and decreasing COX-2 expression.

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Effect of Grain Size on the Damping Capacity of Fe-26Mn-4Co-2Al Damping Alloy (Fe-26Mn-4Co-2Al 제진합금의 감쇠능에 미치는 결정립 크기의 영향)

  • Jeong, Kyu-Seong;Kim, Doe-Hoon;Kwon, Soon-Doo;Kang, Chang-Yong
    • Korean Journal of Materials Research
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    • v.28 no.3
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    • pp.129-134
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    • 2018
  • This study was carried out to investigate the effect of grain size on the damping capacity of the Fe-26Mn-4Co-2Al damping alloy. ${\alpha}^{\prime}$ and ${\varepsilon}-martensite$ were formed by cold working, and these martensites were formed with a specific direction and surface relief. With an increase in grain size, the volume fraction of ${\alpha}^{\prime}$ and ${\varepsilon}-martensite$ increased by decrement the austenite phase stability. This volume fraction more rapidly increased in cold-rolled specimen than in the specimen that was not cold-rolled. The damping capacity also increased more with the augmentation an increased grain size and more rapidly increased in cold-rolled specimen than in the specimen that was not cold rolled. The effect of grain size on the damping capacity was larger in the cold-rolled specimen than the specimen that was not cold-rolled. Damping capacity linearly increased with an increase in volume fraction of ${\varepsilon}-martensite$. Thus, the damping capacity was affected by the ${\varepsilon}-martensite$.

The Effects of Sunghyangjunggi-san and Gwackhyangjunggi-san Extracts on Cerebral Ischemia Following the MCA Occlusion in Rat (흰쥐의 중대뇌동맥 결찰로 유발된 뇌허혈에서 성향정기산과 곽향정기산이 신경세포에 미치는 효과)

  • 김선영;이원철
    • The Journal of Korean Medicine
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    • v.22 no.4
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    • pp.142-150
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    • 2001
  • Objectives : The purpose of this investigation is to evaluate and compare the effects of Sunghyangjunggi-san (SH) and Gwackhyangjunggi-san (GH) extracts on reperfusion following the MCA occlusion in rats. Methods : To evaluate the effect of Sunghyangjunggi-san (SH) and Gwackhyangjunggi-san (GH) extracts on reperfusion following the MCA occlusion, the volume of cerebral infarction and edema were measured and the change of the CA1 pyramidal neurons in the hippocampus were investigated by light microscopy. Results : 1. The infarction volume of the control group was 23.6%, that of the GH group was 23.7%, and that of the SH group was 18.5%. 2. The brain edema volume of the control group increased by 16% compared with that of the normal group, that of the GH group increased by 14%, and that of the SH group increased by 9%. 3. The number of surviving pyramidal neurons in the CAI area of the hippocampus was investigated under light microscopy. In the control group, few surviving pyramidal neurons excisted (mean 6.4) and similarly in the GH group (mean 8.5), but in the SH group, the number of surviving pyramidal neurons was significantly higher, to the mean 18.4. Conclusions : According to the above results, in regard to the damage of neurons following cerebral ischemia, the GH group has little effect of the protection of neurons compared to the control group, but the SH group has a remarkable effect.

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ROI Study for Diffusion Tensor Image with Partial Volume Effect (부분용적효과를 고려한 확산텐서영상에 대한 관심영역 분석 연구)

  • Choi, Woohyuk;Yoon, Uicheul
    • Journal of Biomedical Engineering Research
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    • v.37 no.2
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    • pp.84-89
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    • 2016
  • In this study, we proposed ameliorated method for region of interest (ROI) study to improve its accuracy using partial volume effect (PVE). PVE which arose in volumetric images when more than one tissue type occur in a voxel, could be used to reduce an amount of gray matter and cerebrospinal fluid within ROI of diffusion tensor image (DTI). In order to define ROIs, individual b0 image was spatially aligned to the JHU DTI-based atlas using linear and non-linear registration (http://cmrm.med.jhmi.edu/). Fractional anisotropy (FA) and mean diffusivity (MD) maps were estimated by fitting diffusion tensor model to each image voxel, and their mean values were computed within each ROI with PVE threshold. Participants of this study consisted of 20 healthy controls, 27 Alzheimer's disease and 27 normal-pressure hydrocephalus patients. The result showed that the mean FA and MD of each ROI were increased and decreased respectively, but standard deviation was significantly decreased when PVE was applied. In conclusion, the proposed method suggested that PVE was indispensable to improve an accuracy of DTI ROI study.

A Study on the Effect of the Permeability to Yield Weight of Paddy Rice on the Compressed Soil (압축토양의 투수성과 수도생육 및 수확량에 관한 연구)

  • 조형용
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.15 no.2
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    • pp.2968-2979
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    • 1973
  • The aim of this study was to bring light on the effect of permeability to yield weight of paddy rice on the compressed soil. a) The percolation volume during the growth of paddy rice reduced, while the degree of compression on soil column increased and varied by the evaporation and absorption volumn. b) The percolation volume in the natural soil column was notably low compared with that of in the artificial and had little influence to the variation of permeabilty by compression. c) The results in growth of paddy rice were best on the section of low compression and the yield weight reduced, while the degree of compression on the soil column increased. d) The relationship between the yield weight and percolation volumn, under the condition when percolation volume is 1mm/day, had little difference in the yield weight but immediately reduced under $0.5{\sim}1.0mm/day$. The consequences of investigation are not so perfect, but have done my best to get some new data for effect on additional yield by inquiring into influences of permeability to the yield weight of paddy rice on compressed paddy field. I will have a great pleasure if treatise helps investigaters or the men of affairs in this field.

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