• Applied Chemistry for Engineering
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• v.8 no.1
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• pp.67-75
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• 1997

Heterogeneous cation exchange membrane consisting of cation exchange resin particles (diameter of less than $149{\mu}$) which are finely dispersed in a polyethylene matrix, were produced as forms of sheet. The characteristics were measured after treating hot water or saturated sodium chloride. When membranes were treated with hot water or saturated sodium chloride, cation exchange resin particles swell and expand pushing away the polyethylene matrix of membranes. The above treatment results the formation of narrow cavities between a cation exchange resin particles and polyethylene matrix, and the formation of fine micro-cracks on the polyethylene matrix. Thus, we were obtained good physical and electrochemical properties. On the treatment with hot water or saturated sodium chloride, the optimum conditions for good heterogeneous cation exchange membrane were treatment time of 30min and treatment temperature of $90^{\circ}C$.

• Korean Journal of Materials Research
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• v.8 no.11
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• pp.1061-1066
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• 1998

The synthesises of anion exchange resin from 4vinylpyridine-divinyIbenzene(4-VP-DVB) were intented to separate boron ion. The heterogeneous anion exchange membranes were prepared with polyethylene(PE) matrix bythe hot press method. The prepared exchange membranes were characterized by FT-IR, conductormeter and pH meter to confirm structural, mechanical and electrochemical properties. Their capacities were measured by changing floe rate and voltage. The best seperation capacity was appeared in the heterogeneous membrane which contains 50 wt % 4-VP-DVB resin within PE matrix. The heterogeneous membranes treated with acid were better than that treated with water. Results from this experiment were indicated that the optimal flow rate, voltage. and time in the seperation of boron ion were lOml/min, 18volts, and 4 hours respectively.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.05a
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• pp.95-98
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• 2003

• Proceedings of the Membrane Society of Korea Conference
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• 2003.07a
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• pp.33-36
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• 2003

This research was aimed at developing new catalytic membrane reactors to be used for : i) partial oxidation of toluene (to benzaldehyde and benzoic acid) ii) oxidative dehydrogenation of propane iii) complete oxidation of propane and toluene. The reactor is particularly useful for the optimisation and the industrial development of heterogeneous catalytic processes, particularly for those processes where it is necessary to control the reactants stoichiometry in the reaction zone. This control limits consecutive reactions, thus obtaining high selectivity with industrially interesting conversions. This presentation will concentrate on the partial oxidation of toluene.

• Journal of Oral Medicine and Pain
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• v.46 no.2
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• pp.63-68
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• 2021

Mucous membrane pemphigoid (MMP) is a heterogeneous group of chronic, autoimmune subepithelial blistering diseases, predominantly involving oral mucosal membrane. Because of its pathophysiology of autoimmune reaction, MMP-related gingivitis would not respond to conventional periodontal treatments. We present a case of a 65-year-old female with a chief complaint of chronic generalized buccal gingivitis, unimproved after periodontal treatment for four months. Based on the clinical findings, histological examination, and direct immunofluorescence microscopy, it was diagnosed as MMP. The symptoms were relieved with immunomodulatory therapy using corticosteroids and the supportive management of professional plaque control. MMP can cause pathological involvement throughout the oral and other mucosae of the body, thus leading to functional impairment through repeated inflammatory cascades. Therefore, accurate diagnosis is essential to properly manage local and possible systemic complications of MMP.

• Applied Chemistry for Engineering
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• v.7 no.6
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• pp.1132-1141
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• 1996

Heterogeneous cation exchange membrane(HCEM) was prepared with LLDPE(Linear Low Density Poly-ethylene) as binder, powdered cation exchange resins($diameter{\leq}149{\mu}m$) as ion-exchange material and glycerol as additive for electrodialysis and electrodeionization system. The weight ratio of (binder/ion exchange)/glycerol was (60%/40%)/5%, (55%/45%)/5%, (50%/50%)/5% and (40%/60%)/5%. The characterization of prepared HCEM was evaluated on mechanical, electrochemical, morphology and ion permeable properties. It was compared with commercial membrane. Electrochemical properties of HCEM of (50%/50% )/5% were very similar to value of IONPURE(commercial membrane), in which ion exchange capacity, ion transfer number and membrane resistance were to be 1.733meq/g, 0.96 and $16.08{\Omega}/cm^2$, respectively. Ion permeability of the membrane was better than that of IONPURE membrane. Compared with IONPURE membrane, the HCEM had a higher tensile strength and lower elongation and modulus, in which HCEM had tensile strength of $62.33kg/cm^2$, elongation of 87.42% and modulus of $658.53kg/cm^2$. The HCEM of (50%/50% )15% was optimum combination.

• Membrane Journal
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• v.28 no.5
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• pp.307-319
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• 2018

Ion-exchange membrane (IEM) has fixed charge groups and is a separation membrane which is capable of selectively transporting ions of the opposite polarity. Recently, the interest in IEMs has been increasing as the importance of the desalination and energy conversion processes using them as the key components has increased. Since the IEMs determine the efficiency of the above process, it is necessary to improve the separation performance and durability of them and also to lower the expensive membrane price, which is a hindrance to the widening application of the IEM process. Therefore, it is urgent to develop high-performance and low-cost IEMs. Among various types of IEMs, pore-filled membranes prepared by filling ionomer into a porous polymer substrate are intermediate forms of homogeneous membranes and heterogeneous membranes. The production cost would be cheap like the case of heterogeneous membranes because of the use of inexpensive supports and the reduction of the amount used of raw materials, and at the same time, they exhibit excellent electrochemical characteristics close to homogeneous membranes. In this review, major research and development trends of pore-filled IEMs, which are attracting attention as high-performance and low-cost IEMs, have been summarized and reported according to the application fields.

• Transactions on Electrical and Electronic Materials
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• v.13 no.6
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• pp.305-309
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• 2012

In this study, ZnO nanorods and $SnO_2$-CuO heterogeneous oxide were grown on membrane-type gas sensor platforms and the sensing characteristics for carbon monoxide (CO) were studied. Diaphragm-type gas sensor platforms with built-in Pt micro-heaters were made using a conventional bulk micromachining method. ZnO nanorods were grown from ZnO seed layers using the hydrothermal method, and the average diameter and length of the nanorods were adjusted by changing the concentration of the precursor. Thereafter, $SnO_2$-CuO heterogeneous oxide thin films were grown from evaporated Sn and Cu thin films. The average diameters of the ZnO nanorods obtained by changing the concentration of the precursor were between 30 and 200 nm and the ZnO nanorods showed a sensitivity value of 21% at a working temperature of $350^{\circ}C$ and a carbon monoxide concentration of 100 ppm. The $SnO_2$-CuO heterogeneous oxide thin films showed a sensitivity value of 18% at a working temperature of $200^{\circ}C$ and a carbon monoxide concentration of 100 ppm.

• Mycobiology
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• v.29 no.1
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• pp.15-18
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• 2001

Protoplast fusion is a useful technique for establishing fungal hybrids to overcome the natural barriers. The ultrastructure of protoplast and its fusion process were observed using a scanning electron microscopy(SEM) and a transmission electron microscopy(TEM). The protoplasts were variable in size from $0.5{\sim}15{\mu}m$ in diameter, and the mean diameter was about $3{\sim}5{\mu}m$. It was impossible to discriminate protoplasts of Lentinula edodes from protoplasts of Coriolus versicolor by size and surface structure. Big aggregates of the dehydrated protoplasts were observed, after polyethylene glycol 4000 treatment. Nucleus, mitochondria, lipid granules and various vesicles having granules were scattered in the cytoplasm. The vesicles were heterogeneous in size and vary from one protoplast to another. The fused membrane layer of the two protoplasts was observed. Time protoplast membrane contact and reorganization of membrane components were essential condition for protoplast fusion. Transmission electron micrograph showed fused protoplasts and flattening of the cells in the area of the membrane contact. We hope that our electron microscopic observations provide some insights into the understanding of the fusion process of protoplast in fungi.

• Journal of Pharmaceutical Investigation
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• v.19 no.1
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• pp.39-46
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• 1989

The clonidine transport mechanism through the skin was investigated with assumptions that epidermis is heterogeneous and two-layer membrane. Immobilization of clonidine was not found in stratum corneum but in viable epidermis. The sorption in the viable epidermis agreed with the dual sorption theory. Diffusion coefficient in stratum corneum was five order magnitude less than that in viable epidermis. In viable epidermis, the ratio of true diffusivity to apparent diffusivity increased initially then decreased as a function of clonidine concentration, and the true diffusivity was always larger than the apparent diffusivity.