• Title/Summary/Keyword: CTE

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Empirical Study for the Effects of Filler Shape on the Thermal Expansion Coefficient of PP Composites (충전제 함량 및 형태에 따른 PP복합체의 열팽창계수 변화에 대한 실증적 연구)

  • Hwang, Hyo-Yeon;Jeoung, Sun-Kyoung;Shim, Je-Hyeon;Kim, Jae-Min;Lee, Kee-Yoon
    • Polymer(Korea)
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    • v.34 no.4
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    • pp.352-356
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    • 2010
  • The effects of the filler shapes and contents on the coefficient of thermal expansion (CTE) for polypropylene (PP) composites which included three dimensional ellipsoids ($a_1>a_2>a_3$), as determined by two aspect ratios (${\rho}_\alpha=a_1/a_3$ and ${\rho}_\beta=a_1/a_2$) were analyzed by the theoretical approach proposed by Lee and Paul and compared with the experimental results. The shapes of fillers in the composites were various, such as spherical, fiber, disc, and ellipsoid, using barium sulfate, glass fiber, and mica. The longitudinal CTE of barium sulfate whose shape was sphere ($\rho_\alpha=\rho_\beta=1$) decreased. For the glass fiber, primary aspect ratio decreased with the filler content, and longitudinal CTE decreased as filler contents increased. Normal CTE initially increased in the lower filler content. For the mica, longitudinal and transverse CTE decreased but normal CTE increased in the lower filler content like predicted values.

Antioxidant-mediated Analgesic Effects of Corydalis Tuber Aqueous Extracts on the Rat Experimental Dysmenorrhea (월경통 랫트 모델에서 현호색 열수 추출물의 항산화 매개 진통 효과)

  • Ji-Won Lee;Dong-Chul Kim
    • The Journal of Korean Obstetrics and Gynecology
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    • v.37 no.1
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    • pp.23-39
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    • 2024
  • Objectives: Primary dysmenorrhea (PD) is defined as abdominal pain during menstruation period in the absence of an identifiable pathological lesion. Corydalis tuber (CT) is an herbal medicine that has an excellent effect in relieving pain and convulsions. The purpose of this study is to observe the effect of Corydalis tuber aqueous extracts (CTe) on primary dysmenorrhea. Methods: The rats were injected with estradiol benzoate subcutaneously for 10 days (2.5 mg/kg on the first and 10th days, and 1 mg/kg from the 2~9th day). Oxytocin 1 U/kg was treated by peritoneal injection 1 hour after the last 10th injection of estradiol benzoate. CTe 400, 200 and 100 mg/kg were administered orally, once a day for 10 days at 30 minutes after each estradiol benzoate treatment. The results of CTe were compared to those of IND 5 mg/kg orally treated rats. Results: As results of estradiol benzoate and oxytocin administration, noticeable decreases of body weights and gains, uterus weights were observed with congestion and enlargement of the uterus at gross inspections, and increases of abdominal writhing responses, uterus MDA levels, GSH contents, SOD and CAT activities. However, these oxidative stress mediated PD signs were dose-dependently decreased by 10 consecutive days of oral administration of three different doses of CTe 400, 200 and 100 mg/kg as comparable to those of IND 5 mg/kg in CTe 200 mg/kg. Conclusions: CTe had a significant improvement effect on primary dysmenorrhea in the PD rat model induced by estrogen benzoate and oxytocin.

Measurement of Thermal Expansion Coefficient of Package Material Using Strain Gages (스트레인 게이지를 이용한 패키지 재료의 열팽창계수 측정)

  • Yang, Hee-Gul;Joo, Jin-Won
    • Journal of the Microelectronics and Packaging Society
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    • v.20 no.3
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    • pp.37-44
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    • 2013
  • It is well known that thermal deformation of electronic packages with Pb-Sn solder and with lead-free solder is significantly affected by material properties consisting the package, as well as those of the solder itself. In this paper, the method for determining coefficient of thermal expansion(CTE) of new material is established by using temperature characteristic of strain gages, and the CTE of molding compound are obtained experimentally. The temperature-dependent CTE of molding compound for Pb-Sn solder and that for lead-free solder are obtained by using strain measurements with well known steel specimen and aluminium specimen as reference specimens, and the CTE's are also measured non-contactly by using moire interferometry. Those results are compared, and the agreement between the two types of strain gage experiment and the moire experiment show the strain gage method used in this paper to be reliable. In the case of the molding compound for Pb-Sn solder, the CTE is measured as approximately $15.8ppm/^{\circ}C$ regardless of the temperature. In the case for the lead-free solder, the CTE is measured as of approximately $9.9ppm/^{\circ}C$ below the temperature of $100^{\circ}C$, and then the CTE is increased sharply depending on the temperature, and reaches to $15.0ppm/^{\circ}C$ at $130^{\circ}C$.

Effect of Nano Grain Growth on Coefficient of Thermal Expansion in Electroplated Fe-Ni Invar Alloy (Fe-Ni Invar 합금에서 나노 결정립 성장이 열팽창계수에 미치는 영향)

  • Yim, Tai Hong;Choe, Byung Hak;Jeong, Hyo Tae
    • Korean Journal of Materials Research
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    • v.24 no.10
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    • pp.515-519
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    • 2014
  • The aim of this paper is to consider the effect of annealing on the coefficient of thermal expansion (CTE) of electroplated Invar Fe-Ni alloy. The CTE of the as-electroplated alloy is lower than those of alloys annealed at $400^{\circ}C$ and $800^{\circ}C$. XRD peaks become sharper as the as-electroplated alloy is annealed, which means the grain growth. The average grain sizes of as-electroplated and as-annealed alloys at $400^{\circ}C$ and $800^{\circ}C$ are 10 nm, 70 nm, and $2{\mu}m$, respectively, as determined by TEM and EBSD analyses. The CTE variation for the various grain sizes after annealing may come from the magnetostriction effect, which generates strain due to changes in the magnetization state of the alloys. The thermal expansion coefficient is considered to be affected by nano grain size in electroplated Fe-Ni Invar alloys. As grain size decreases, ferromagnetic forces might change to paramagnetic forces. The effect of lattice vibration damping of nano grain boundaries could lead to the decrease of CTE.

The protective effects of ethanolic extract of Clematis terniflora against corticosterone-induced neuronal damage via the AKT and ERK1/2 pathway

  • Noh, Yoohun;Cheon, Seungui;Kim, In Hye;Kim, Inyong;Lee, Seung-Ah;Kim, Do-Hee;Jeong, Yoonhwa
    • BMB Reports
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    • v.51 no.8
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    • pp.400-405
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    • 2018
  • Chronic stress induces neuronal cell death, which can cause nervous system disorders including Parkinson's disease and Alzheimer's disease. In this study, we evaluated the neuroprotective effects of Clematis terniflora extract (CTE) against corticosterone-induced apoptosis in rat pheochromocytoma (PC12) cells, and also investigated the underlying molecular mechanisms. At concentrations of 300 and $500{\mu}g/ml$, CTE significantly decreased apoptotic cell death and mitochondrial damage induced by $200{\mu}M$ corticosterone. CTE decreased the expression levels of endoplasmic reticulum (ER) stress proteins GRP78, GADD153, and mitochondrial damage-related protein BAD, suggesting that it downregulates ER stress evoked by corticosterone. Furthermore, our results suggested that these protective effects were mediated by the upregulation of p-AKT and p-ERK1/2, which are involved in cell survival signaling. Collectively, our results indicate that CTE can lessen neural damage caused by chronic stress.

Warpage Simulation by the CTE mismatch in Blanket Structured Wafer Level 3D packaging

  • Kim, Seong Keol;Jang, Chong-Min;Hwang, Jung-Min;Park, Man-Chul
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.22 no.1
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    • pp.168-172
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    • 2013
  • In 3D wafer-stacking technology, one of the major issues is wafer warpage. Especially, The important reason of warpage has been known due to CTE(Coefficient of Thermal Expansion) mismatch between materials. It was too hard to choose how to make the FE model for blanket structured wafer level 3D packaging, because the thickness of each layer in wafer level 3D packaging was too small (micro meter or nano meter scale) comparing with diameter of wafer (6 or 8 inches). In this study, the FE model using the shell element was selected and simulated by the ANSYS WorkBench to investigate effects of the CTE on the warpage. To verify the FE model, it was compared by experimental results.

Neuroprotective Effect according to Reactive Oxygen Species Scavenging Activity from Extracts of Cudrania tricuspidata Leaves (활성산소 소거활성에 따른 꾸지뽕잎 추출물의 신경세포 보호 효과)

  • Kang, Young-Kyoung;Lee, Eun-Ah;Park, Hae-Ryong
    • Korean journal of food and cookery science
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    • v.28 no.6
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    • pp.821-828
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    • 2012
  • In an attempt to identify the neuroprotective effect of Cudrania tricuspidata (CT) leaves against ROS (reactive oxygen species)-induced oxidative stress in neuronal cells, the extracts from CT leaves were investigated using PC12 cells and N18-RE-105 cells. The methanolic and ethanolic extracts from CT were denoted as CTM (Cudrania tricuspidata Leaves methanolic extracts) and CTE (Cudrania tricuspidata Leaves ethanolic extracts), respectively. The neuroprotective effects of the extracts were measured by DCF-DA assay, MTT reduction assay, and LDH release assay. The PC12 cells exposed to $H_2O_2$-induced oxidative stress and the N18-RE-105 cells exposed to glutamate-induced oxidative stress were treated with various concentrations of CTM and CTE. The results, CTM treatments resulted in the induction of a dose-dependent protective effect in PC12 cells and N18-RE-105 cells. Interestingly, CTE also showed neuroprotective effect in PC12 cells and N18-RE-105 cells. Therefore, these results suggest that CTM and CTE could be a new potential candidate as neuroprotective agents against ROS-induced oxidative stress in neuronal cells.

Thermal analysis on composite girder with hybrid GFRP-concrete deck

  • Xin, Haohui;Liu, Yuqing;Du, Ao
    • Steel and Composite Structures
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    • v.19 no.5
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    • pp.1221-1236
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    • 2015
  • Since the coefficients of thermal expansion (CTE) between concrete and GFRP, steel and GFRP are quite different, GFRP laminates with different laminas stacking-sequence present different thermal behavior and currently there is no specification on mechanical properties of GFRP laminates, it is necessary to investigate the thermal influence on composite girder with stay-in-place (SIP) bridge deck at different levels and on different scales. This paper experimentally and theoretically investigated the CTE of GFRP at lamina's and laminate's level on micro-mechanics scales. The theoretical CTE values of laminas and laminates agreed well with test results, indicating that designers could obtain thermal properties of GFRP laminates with different lamina stacking-sequence through micro-mechanics methods. On the basis of the CTE tests and theoretical analysis, the thermal behaviors of composite girder with hybrid GFRP-concrete deck were studied numerically and theoretically on macro-mechanics scales. The theoretical results of concrete and steel components of composite girder agreed well with FE results, but the theoretical results of GFRP profiles were slightly larger than FE and tended to be conservative at a safety level.

Corydalis Tuber Induces Apoptosis in MCF-7 Cells, Via Inhibition of Bcl-2 and $Bcl-_{XL}$ Expression (현호색 메탄올 추출물이 Bcl-2와 $Bcl-_{XL}$ 발현 억제를 통해 유방암 세포의 자멸사에 미치는 영향)

  • Park, Young-Ae;Kim, Dong-Chul
    • The Journal of Korean Obstetrics and Gynecology
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    • v.21 no.4
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    • pp.90-103
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    • 2008
  • 목적 : 본 연구는 현호색의 메탄올 추출물(Corydalis Tuber Extract:CTE)이 인간 유방암 세포인 MCF-7 세포의 자멸사에 미치는 영향을 알아보고자 하였다. 방법 : 현호색 메탄올 추출물로 인간유방암에서 유래된 MCF-7 세포를 처리하였다. CTE의 세포자멸사 유도 효과는 MTT, FACS, TUNEL, DNA laddering and immunoblot assay를 통하여 측정하였다. 결과: 본 연구에서 현호색 메탄올 추출물은 MCF-7 세포의 활성을 감소시켰다. CTE로 처리한 MCF-7 세포는 용량에 따라 세포 자멸사 과정이 증가했다. CTE에 노출하였을 때 Bcl-2와 $Bcl-_{XL}$의 발현을 억제하고, 미토콘드리아로부터 세포질로 cytochrome-c를 방출하며, caspase와 PARP의 절단을 유발하여 세포자멸사가 증가했다. 현호색 메탄올 추출물에 존재하는 성분중에서 coptisine이 세포 활성도를 효과적으로 감소시킨 것으로 사료된다. 결론: 실험결과 현호색 메탄올 추출물이 유방암의 임상 치료에 있어 가능성 있는 치료 방법이 될 수 있을 것으로 사료된다.

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Epidemiological application of the cycle threshold value of RT-PCR for estimating infection period in cases of SARS-CoV-2

  • Soonjong Bae;Jong-Myon Bae
    • Journal of Medicine and Life Science
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    • v.20 no.3
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    • pp.107-114
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    • 2023
  • Epidemiological control of coronavirus disease 2019 (COVID-19) is needed to estimate the infection period of confirmed cases and identify potential cases. The present study, targeting confirmed cases for which the time of COVID-19 symptom onset was disclosed, aimed to investigate the relationship between intervals (day) from symptom onset to testing the cycle threshold (CT) values of real-time reverse transcription-polymerase chain reaction. Of the COVID-19 confirmed cases, those for which the date of suspected symptom onset in the epidemiological investigation was specifically disclosed were included in this study. Interval was defined as the number of days from symptom onset (as disclosed by the patient) to specimen collection for testing. A locally weighted regression smoothing (LOWESS) curve was applied, with intervals as explanatory variables and CT values (CTR for RdRp gene and CTE for E gene) as outcome variables. After finding its non-linear relationship, a polynomial regression model was applied to estimate the 95% confidence interval values of CTR and CTE by interval. The application of LOWESS in 331 patients identified a U-shaped curve relationship between the CTR and CTE values according to the number of interval days, and both CTR and CTE satisfied the quadratic model for interval days. Active application of these results to epidemiological investigations would minimize the chance of failing to identify individuals who are in contact with COVID-19 confirmed cases, thereby reducing the potential transmission of the virus to local communities.