• Design & Manufacturing
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• 제17권2호
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• pp.27-32
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• 2023

Liquid silicon rubber (LSR) has fine thermal compatibility and is widely used in various fields such as medical care and automobiles because it is easy to implement products with good fluidity. With the recent development of flexible sensors, the focus has been on manufacturing conductive elastomers, such as silicone as elastic materials, and carbon black, CNT, and graphene are mainly used as nanomaterials that impart conductive phases. In this study, mechanical behavior and curing behavior were measured and analyzed to manufacture a CB-LSR complex by adding Carbon Black to LSR and to identify properties. As a result of the compression test, the elastic modulus tended to increase as carbon black was added. When the swelling test and the compression set test were conducted, the swelling rate tended to decrease as the content of carbon black increased, and the compression set tended to increase. In addition, DSC measurements showed that the total amount of reaction heat increased slightly as the carbon black content increased. It is considered that carbon black was involved in the crosslinking of LSR to increase the crosslinking density and have a positive effect on oil resistance reinforcement.

• Journal of Korean Neurosurgical Society
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• 제58권3호
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• pp.286-290
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• 2015

We report a case of neurilemmoma of deep peroneal nerve sensory branch that triggered sensory change with compression test on lower extremity. After resection of tumor, there are evoked thermal changes on pre- and post-operative infrared (IR) thermographic images. A 52-year-old female presented with low back pain, sciatica, and sensory change on the dorsal side of the right foot and big toe that has lasted for 9 months. She also presented with right tibial mass sized 1.2 cm by 1.4 cm. Ultrasonographic imaging revealed a peripheral nerve sheath tumor arising from the peroneal nerve. IR thermographic image showed hyperthermia when the neurilemoma induced sensory change with compression test on the fibular area, dorsum of foot, and big toe. After surgery, the symptoms and thermographic changes were relieved and disappeared. The clinical, surgical, radiographic, and thermographic perspectives regarding this case are discussed.

• Elastomers and Composites
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• 제53권2호
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• pp.80-85
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• 2018

Chloro isobutylene isoprene rubber (CIIR) and ethylene propylene diene monomer (EPDM) compounded with other formulation chemicals, depending on the polymer blend, were prepared by mechanical mixing. After manufacturing the rubber vulcanizate by compression molding with a hot press, the mechanical and thermal properties including thermal conductivity, rebound resilience of the CIIR/EPDM blends were measured. As the EPDM rubber content increased, hardness and tension set showed a tendency to increase. Pure CIIR exhibited the lowest tensile strength; however, tensile strength increased with loading of EPDM rubber. On the other hand, in CIIR rubber, which is usually a low-rebound elastomer owing to a high damping effect, rebound resilience exhibited an increasing trend as the content of EPDM rubber increased. As the EPDM rubber content increased, thermal stability was improved due to reduction of decomposition rate in the rubber region of the blend vulcanizate.

• 대한기계학회논문집A
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• 제26권11호
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• pp.2355-2363
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• 2002

The accompanying paper, Part 1, has presented the physical modeling and basic numerical analysis results of both the flow-induced and thermally-induced residual stress and birefringence in injection molded center gated disks. The present paper, Part II, has attempted to investigate the effects of various processing conditions of injection/compression molding process on the residual stress and birefringence. The birefringence is significantly affected by injection melt temperature, packing pressure and packing time. Birefringence in the shell layer increases as melt temperature gets lower. The inner peak of birefringence increases with packing time and packing pressure. On the other hand, packing pressure, packing time and mold wall temperature affect the thermally-induced residual stress rather significantly in the shell layer, but insignificantly in the core region. Injection/compression molding has been found to reduce the birefringence in comparison with the conventional injection molding process. In particular, mold closing velocity and initial opening thickness in the compression stage of injection/compression molding process have significant effect on the flow-induced birefringence, but not on tile thermal residual stress and the thermally induced birefringence.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.589-592
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• 2005

Molding shrinkage s variation is one of the problems to be solved in conventional injection molding. Despite many trying-out has been to solve these, intrinsic causes of shrinkage such as orientation and thermal exchange between melt and mold has yet not solved. For reducing shrinkage and residual stress on molding, injection compression molding process was invented. In this study, experiments about effect of injection compression molding's parameters on shrinkage of molding were conducted with PMMA and compared with conventional injection molding's shrinkage. Before the injection compression molding experiment, molding shrinkage rate was predicted by analyzing pvT graph and was compared with the results of experiment. The shrinkage rate of injection compression molding was lower than convention injection molding' one but was different from the predicted shrinkage. The reason was observed that experiment mold as not positive type, flowing backward of melt into nozzle and unreasonable mechanism of injection molding machine.

• 한국안전학회지
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• 제24권5호
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• pp.1-5
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• 2009

NiTiCu alloys can produce a large force per unit volume and operate with a simple mechanism. For this reasons, it has been widely studied for application as a micro actuator. So in this study, one-way and two way shape memory effects of Ti-42.5at%Ni-2.0at%Cu alloys are studied. In the case of one-way shape memory effects, shape memory recoverable stress and strain of this alloys were measured by means of tension and compression tests under constant temperature. The strains by tension and compression stress were perfectly recovered by heating at any testing conditions also shape memory recoverable stress increased to 116 MPa in tension tests and to 260 MPa in compression tests. In the case of two-way shape memory effects, transformation temperatures from thermal cycling under constant uniaxial applied tension and compression loads linearly increased by increasing external loads and their maximum recoverable strain is 3.8% at 100MPa tensile condition and 2.2% at 125 MPa compression condition.

• E2M - 전기 전자와 첨단 소재
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• 제9권5호
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• pp.450-454
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• 1996

Maxwell-Displacement-Current(MDC) measuring technique has been applied to the study of monolayers of Dilauroylphosphatidylcholine (L-.alpha.-DLPC) and Dimyristoylphosphatidylcholine (L-.alpha.-DMPC). The displacement current was generated from monolayers on a water surface by monolayer compression. Displacement current was generated when the area per molecule was about 250.angs.$^{2}$, 280.angs.$^{2}$. Displacement current was generated in the gas state, gas/liquid state, and liquid state in the course of monolayer compression. The orientational change of molecules in monolayers was discussed on the basis of the MDCs obtained. Finally, we measured differential thermal analysis of sample.

• Macromolecular Research
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• 제16권5호
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• pp.467-472
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• 2008

Rigid polyurethane foams (RPUFs) were fabricated from crude MDI (CMDI) and polypropylene glycols (PPGs) of various isocyanate indices with a physical blowing agent (HFC 365mfc). There was a tendency for the gel time to decrease and the tack-free time to increase with increasing index value. With increasing index value the foam density and compression strength decreased and the glass transition temperature, dimension stability and thermal insulation increased, while the cell size and closed cell content were virtually unchanged. Allophanate crosslinks and condensation reactions between the isocyanate groups, which are favored with a high index value, exerted significant effects on the properties of RPUFs.

• 기술사
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• 제44권4호
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• pp.39-43
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• 2011

To cope with recent high gas prices and global warming phenomenon, the latest gasoline engine technologies are focusing on direction injection, downsizing by turbo charging, variable compression ratio, controlled auto Ignition to enhance fuel efficiency and satisfy emission regulations. The variable valve train technology will be a basement for these innovative technologies in internal combustion engines and is supposed to play a key role to improve low thermal efficiency and pumping loss in gasoline engine caused by low compression ratio and throttled operation respectively.

• International Journal of Oral Biology
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• 제34권3호
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• pp.157-164
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• 2009

We recently described a novel animal model of trigeminal neuropathic pain following compression of the trigeminal ganglion (Ahn et al., 2009). In our present study, we adapted this model using male Sprague-Dawley rats weighing between 250-260 g and then analyzed the behavioral responses of these animals following modified chronic compression of the trigeminal ganglion. Under anesthesia, the rats were mounted onto a stereotaxic frame and a 4% agar solution ($10{\mu}L$) was injected in each case on the dorsal surface of the trigeminal ganglion to achieve compression without causing injury. In the control group, the rats received a sham operation without agar injection. Air-puff, acetone, and heat tests were performed at 3 days before and at 3, 7, 10, 14, 17, 21, 24, 30, 40, 55, and 70 days after surgery. Compression of the trigeminal ganglion produced nociceptive behavior in the trigeminal territory. Mechanical allodynia was established within 3 days and recovered to preoperative levels at approximately 60 days following compression. Mechanical hyperalgesia was also observed at 7 days after compression and persisted until the postoperative day 40. Cold hypersensitivity was established within 3 days after compression and lasted beyond postoperative day 55. In contrast, compression of the trigeminal ganglion did not produce any significant thermal hypersensitivity when compared with the sham operated group. These findings suggest that compression of the trigeminal ganglion without any injury produces prolonged nociceptive behavior and that our rat model is a useful system for further analysis of trigeminal neuralgia.