• Mass Spectrometry Letters
• /
• 제7권3호
• /
• pp.79-83
• /
• 2016

We prepared solid dispersion formulations of quercetin to enhance its solubility and dissolution rate. Various quercetin-loaded solid dispersion were tested with quercetin, poloxamer 407, and carrier such as hydroxypropyl methyl cellulose (HPMC), polyethylene glycol 8000 (PEG 8000), and polyvinylpyrrolidone K40 (PVP K40) using solvent evaporation and freeze drying methods in terms of both the aqueous solubility and the dissolution rates of quercetin. The solubility of quercetin as its solid dispersion formulations was markedly improved compared with that of quercetin powder. Especially, highest solubility of quercetin was observed when HPMC was used as a carrier. The cumulative dissolution of quercetin within 360 min from solid dispersion composed of quercetin, poloxamer 407, and HPMC was 8.8-fold higher than the dissolution of pure quercetin. The results of powder X-ray diffraction (XRD) and scanning electron microscope (SEM) indicated that quercetin transformed from a crystalline to an amorphous form through the solid dispersion formulation process. These results suggest that the solid dispersion formulation of quercetin with poloxamer 407 and HPMC could be a promising option for enhancing the solubility and dissolution rate of quercetin.

• Journal of the Korean Vacuum Society
• /
• 제5권4호
• /
• pp.341-347
• /
• 1996

We fabricated the effective $Cu_2S$/CdS solar cells with large area by a spray pyrolysis method. In preparation process, we investigated the process parameters which directly influenced the efficiency of solar cell, such as the grid contact for electrodes, the temperature condition of CdS spray and the junction characteristics of $Cu_2S$ layer, by scanning electron microscope(SEM), x-ray diffraction(XRD) and temperature dependent optical absorption and photoconductivity. The $Cu_2S$/CdS solar cell with area of 1$\textrm{cm}^2$ showed the efficient of 3.15% under air mass 2(AM2) spectrum irradiation with 75mW/$\textrm{cm}^2$.

• Resources Recycling
• /
• 제31권6호
• /
• pp.81-91
• /
• 2022

The use of lithium-ion batteries increases significantly with the rapid spread of electronic devices and electric vehicle and thereby an increase in the amount of waste batteries is expected in the near future. Therefore, studies are continuously being conducted to recover various resources of cathode active material (Ni, Co, Mn, Li) from waste battery. In order to recover the cathode active material, black mass is generally recovered from waste battery. The general process of recovering black mass is a waste battery collection - discharge - dismantling - crushing - classification process. This study focus on the crushing/classification process among the processes. Specifically, the particle size distribution of various samples at each crushing/classification step were evaluated, and the particle shape of each particle fraction was analyzed with a microscope and SEM (Scanning Electron Microscopy)-EDS(Energy Dispersive Spectrometer). As a result, among the black mass particle, fine particle less than 74 ㎛ was the mixture of cathode and anode active material which are properly liberated from the current metals. However, coarse particle larger than 100 ㎛ was present in a form in which the current metal and active material were combined. In addition, this study developed a PBM(Population Balance Model) system that can simulate two-species mixture sample with two different crushing properties. Using developed model, the breakage parameters of two species was derived and predictive performance of breakage distribution was verified.

• Korean Chemical Engineering Research
• /
• 제46권3호
• /
• pp.521-528
• /
• 2008

The micro-porous asymmetric PVDF hollow fiber membranes for gas-liquid contactor were prepared by the dry-jet wet phase inversion process and the characteristics of hollow fiber membranes were evaluated by the gas permeation method and scanning electron microscope. The chemical absorbent for removal of $SO_2$ gas was sodium hydroxide at bench scale hollow fiber membrane contactor. The experiments were performed in a counter-current mode of operation with gas in the shell side and liquid in the fiber lumen of the module to examine the effect of various operating variables such as concentration of absorbent, gas flow rate, L/G ratio and concentration of inlet $SO_2$ gas on the $SO_2$ removal efficiency using PVDF hollow fiber membrane contactor. Membrane mass transfer coefficient($k_m$) was calculated by mathematical modeling. The volumetric overall mass transfer coefficient increased with increasing the concentration of absorbent and L/G ratio. The increase of the absorbent concentration and L/G ratio not only provides more sufficient alkalinity but also decreases liquid phase resistance. The volumetric overall mass transfer coefficient increased with increasing gas flow rate due to decreasing the gas phase resistance.

• Korean Journal of Veterinary Service
• /
• 제35권3호
• /
• pp.197-205
• /
• 2012

Despite of a long history of the sulfur on the disease healing effect, there were limited ways of applying sulfur to animal and human. We have developed the detoxified sulfur (non toxic sulfur) method to make it practical and mass production possible through laboring for many years. This study practiced scanning electron microscope (SEM), Energy dispersive X-ray spectrometer (EDS) and secondary ion mass spectrometry (SIMS) analysis to investigate the physicochemical aspect of detoxified sulfur. We also performed the oral toxicity experiment to mice, and anti-bacterial test of the detoxified sulfur. Based on the SEM, EDS and SIMS results, the united particles in the mass form with the similar component intensity with the raw sulfur were observed, and hydrogen sulfide ion (HS-) component which is regarded as a toxic matter, was decreased after detoxification. Indeed, toxicity test on the mice (10 males, 10 females) showed no clinical, histopathological changes with the 5 times amount (2,500 mg/kg) of the actual doses. However, the male-mice showed decreased in body weight by 23.6%, 24.3% in the 7th, 14th day, respectively, after detoxified sulfur. Moreover, the female-mice administered the detoxified sulfur showed decreased in body weight by 28.7% (P<0.05) than that in the control group on the 14th day. The result of antibacterial test on the detoxified sulfur showed antibacterial effect (27%) to inhibit the growth of Staphylococcus aureus. It is shown that detoxified sulfur can be used as feed additive and has an affect on the farm perfomance.

• Archives of Plastic Surgery
• /
• 제38권4호
• /
• pp.494-497
• /
• 2011

Purpose: Schwannoma, a benign peripheral nerve tumor, is slow-growing, encapsulated neoplasm that originates from the Schwann cell of the nerve sheath. Schwannoma most frequently involves the major nerve. Schwannoma occurring in the superficial radial nerve rare. This is a report of our experience with schwannoma arising from the superficial radial nerve with neurologic symptom. Methods: A 55-year-old woman presented with eight-month history of progressive numbness and paresthesia in dorsum of the thumb and index finger. Physical examination revealed a localized mass on the midforearm. Sonographic examination showed an ovoid, heterogenous, hypoechoic lesion, located eccentrically in related to the superficial radial nerve. The lesion was mobile in the transverse but not in the longitudinal axis of the nerve, which was thought to favour schwannoma rather than neurofibroma. At operation, a $20{\times}15mm$ ovoid, yellowish grey mass was seen arising from the superficial radial nerve. The tumor present as eccentric masses over which the nerve fibers are splayed. Using operating microscope, the tumor was removed, preserving the surrounding nerve. Results: Histology confirmed that the mass was a benign schwannoma. There were no postoperative complications. After two months the patient had no clinically demonstrable sensory deficit. Conclusion: An unsusual case of a schwannoma of the superficial radial nerve is presented. In case with neurologic symptom, prompt surgical decompression must be made to prevent further nerve damage and to restore nerve function early.

• Archives of Plastic Surgery
• /
• 제50권6호
• /
• pp.615-620
• /
• 2023

Massive localized lymphedema (MLL) is a rare disease caused by the obstruction of lymphatic vessels with specific clinical morphological and radiological characteristics. People with morbid obesity are mainly affected by MLL. Lymphedema is easily confused with soft tissue sarcoma and requires differential diagnosis, both the possibility of an MLL and also carcinoma manifestations in the soft tissues. The possible causes of massive lymphedema include trauma, surgery, and hypothyroidism. This report is the first case of MLL treated surgically in the Russian Federation. Detailed computed tomography (CT) characteristics and an electron microscope picture of MLL are discussed. A 50-year-old woman (body mass index of 43 kg/m²) with MLL arising from the anterior abdominal wall was admitted to the hospital for surgical treatment. Its mass was 22.16 kg. A morphological study of the resected mass confirmed the diagnosis of MLL. We review etiology, clinical presentation, diagnosis, and treatment of MLL. We also performed an electron-microscopic study that revealed interstitial Cajal-like cells telocytes not previously described in MLL cases. We did not find similar findings in the literature. It is possible that the conduction of an ultrastructural examination of MLL tissue samples will further contribute to the understanding of MLL pathogenesis.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 한국복합재료학회 2005년도 춘계학술발표대회 논문집
• /
• pp.13-16
• /
• 2005

The mechanical properties of composite materials may degrade severely in the presence of damage. Especially, the high-velocity impact such as bird strike, a hailstorm, and a small piece of tire or stone during high taxing, can cause sever damage to the structures and sub-system in spite of a very small mass. However, it is not easy to detect the damage in composite plates using a single technique or any conventional methods. In this paper, the PYDF(polyvinylidene fluoride) film sensors and strain gages were used for monitoring impact damage initiation and propagation in composite laminates. The WT(wavelet transform) and STFT(short time Fourier transform) are used to decompose the sensor signals. A ultrasonic C-scan and a digital microscope are also used to examine the extent of the damage in each case. This research demonstrate how various sensing techniques, PVDF sensor in particular, can be used to characterize high-velocity impact damage in advanced composites.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 한국공작기계학회 2002년도 춘계학술대회 논문집
• /
• pp.167-172
• /
• 2002

Recent years, optical components'are widely used in optical communication industry for high speed and mass storage data processing. Micro grooving of planar lightwave circuit and glass, those are widely used in optical component, are realized by polycrystalline diamond tool with ultrasonic vibration. To know the characteristics of brittle materials cutting, ultrasonic vibration cutting tool and machining system are built for the experiment. Grooving on planar lightwave circuit and glass experiments are performed and their shape are measured by photograph with microscope. It reveals that better groove shape with low chipping of planar lightwave circuit and glass are obtained by micro grooving machining with ultrasonic vibration. These experiments are considered as a possibility to the micro grooving of optical communication components.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 한국정밀공학회 2002년도 춘계학술대회 논문집
• /
• pp.865-868
• /
• 2002

This study investigated the shape deformation of ball projectile(5.56mn) under the low energy impact by the use of the drop weight impact tester. ball projectile(5.56mm) consisted of the copper face with a lead core. The impact conditions were changed with the variations of the mass and the drop height of the impact tup. Shape deformation of ball projectile(5.56mm) after low velocity impact was measured using a video microscope and CCD camera. The test result showed that impact energy by changing of drop height of the impact tup affected shape deformation of ball projectile(5.56mm). So, it is important to study the relativity between shape deformation of ball projectile(5.56mm) and ballistic protection of plate(such as hybrid composite laminates) under the high velocity impact.