• Journal of the Korea Concrete Institute
• /
• v.23 no.2
• /
• pp.203-209
• /
• 2011

The cement industry is expected to face a major set-back in the near future due to its large energy consumption and $CO_2$ production, causing global warming. In order to overcome these environmental problems, this research has bee carried out to find a cement substitute material. One possible cement substitute material is Zeolite cement. In this study, the materialistic characteristics of Zeolite cement mortar were evaluated. Natural Zeolite cement mortar was prepared using alkali activation (NaOH) instead of water ($H_2O$) to determine achievable strength and appropriate mixing ratio. Based on the mixing ratio, functional material was added to alkali active agent to harden Zeolite mortar to develop a highly functional construction material. The study result showed that pure Zeolite cement mortar achieved compressive strength of 42 MPa in 7 days depending on the mixing amount of alkaline catalyst and the hardening temperature, showing high efficiency and possibility as a new construction material.

• Polymer(Korea)
• /
• v.34 no.1
• /
• pp.52-57
• /
• 2010

The low viscous epoxy resin(bisphenol F) with carboxylic acid as the reductants was introduced for high performance and reliability in the ACA with a low melting point alloy filler system. The curing characteristics of the epoxy resin and temperature dependant viscosity characteristic of epoxy resin at the melting temperature of LMPA were investigated by dynamic mode of differential scanning calorimetry (DSC) and rheometer, respectively. Based on these thermo-rheological characteristics of epoxy resin and LMPA, the optimum process system was designed. In order to remove the oxide layer on the surface of LMPA particle, three different types of carboxyl acid-based reductant were added to the epoxy resin. The wetting angles were about $18^{\circ}$ for carboxypropyldisilioxane, and $20.3^{\circ}$ for the carboxy-2-methylethylsiloxane, respectively.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.11a
• /
• pp.545-548
• /
• 2008

In this study aluminium sulfate, Ca(OH)$_2$, K-R Slag and $Na_2SO_4$ were used as active admixtures and their concentration 1, 3, 5, 7 weight percent in cement. The physical properties of active admixtures cement mortar were investigated by flow test and compressive strength. It was found that the resulting active admixtures exhibited the higher compressive strength than OPC mortar up. From the test results, cement mortars added active admixture have a good fundamental property.

• Tuberculosis and Respiratory Diseases
• /
• v.49 no.1
• /
• pp.117-121
• /
• 2000

The mucormycosis is a group of serious opportunistic infections caused by fungi of the class Zygomycetes and order Mucorales. Pulmonary mucormycosis is a relatively rare disease but typically manifested by a rapidly progressive, often fatal pneumonia in patients with diabetes mellitus, hematologic malignant neoplasms, or organ transplants. The radiologic manifestations of pulmonary mucormycosis are nonspecific and include progressive lobar or multilobar consolidations, pulmonary masses and pulmonary nodules. Recently, we experienced a pulmonary mucormycosis in 32-year-old man with uncontrolled diabetes. He complained of cough, left pleuritic chest pain and generalized weakness. Initial chest X-ray finding was the consolidation on the lower lobe of the left lung. On the sixth hospital day, bronchoscopic examination with lung biopsy revealed broad, non-septate hyphae with right-angle branching, diagnostic of mucormycosis, and consequently amphotericin B therapy was started. We performed a lobectomy of the left lower lobe of the lung on 29th hospital day.

• Childhood Kidney Diseases
• /
• v.17 no.1
• /
• pp.13-18
• /
• 2013

Podocytopathy is glomerular lesions characterized by podocyte injury. It is observed in various glomerular diseases, but minimal change disease and focal segmental glomerulosclerosis (FSGS) are the prototypes. In this review, morphologic features of podocyte injury and subtypes of FSGS will be reviewed briefly. Effacement of podocyte foot processes is the most common feature of podocyte injury. As podocytic injury progresses, intracytoplasmic vacuoles, subpodocytic cyst, detachment of podocytes from the glomerular basement membrane and apoptosis develop. Glomerular capillary loops in epithelium-denuded area undergo capillary collapse. Synechia and hyalinosis may accompany this lesion. To manifest segmental sclerosis, podocyte loss above a threshold level may be required. Injured podocytes can injure neighboring intact podocytes, and thereby spread injury within the same lobule. FSGS can be categorized into five subtypes by morphologic characteristics; not otherwise specified (NOS), perihilar, cellular, tip, and collapsing types. Each subtype has been reported to show different clinical courses and associated conditions, but there are controversies on its significance. With recent progress in the discovery of genetic abnormalities causing FSGS and plasma permeability factors, we expect to unravel pathophysiology of FSGS and to understand histological sequences leading to FSGS in near future.

• Applied Chemistry for Engineering
• /
• v.1 no.2
• /
• pp.232-239
• /
• 1990

${\gamma}$-Glycidoxy propyl trimethoxy slilane, CTBN rubber(carboxyl terminated butadiene acrylonitrile rubber) and GMA(glycidyl methacrylate) were reacted with the surface of silica one by one in existence of TEA(triethylamine) or BPO(benzoyl peroxide). The amount of reactant was 2.5~5.8% of treated silica weight. The treated silica was mixed with epoxy resin and MTHPA(methyltetrahydrophthalic anhydride) in the range of 0~60% (wt. %) of total component. The flexural and thermal properties were tested for cured products. In filler content 35~55%, the using of silica treated with silane/rubber or silane/rubber/vinyl represented 25% higher flexural strength, 5% lower flexural modulus and 13% higher than mixing liquid rubber 3% with epoxy resin containing untreated silica.

• Polymer(Korea)
• /
• v.35 no.1
• /
• pp.47-51
• /
• 2011

In this study, illite, an environmental friendly, low cost, and high aspect ratio additive, was used to improve flame retardant property of epoxy and it was fluorinated to enhance dispersion of hydrophilic illite in hydrophobic epoxy by introducing hydrophobic functional groups. Fluorination of illite enhanced illite dispersion ill epoxy solution before curing and that in the complex after curing. These enhanced dispersions were attributed to the increased affinity of illite to hydrophobic epoxy solution induced by fluorination of illite and the increased intercalation of epoxy polymer or exfoliation of illite by epoxy curing. Hence, limited oxygen index(LOI) of fluorinated illite/epoxy complex increased by 24%, compared to that of epoxy, suggesting that the preparation of fluorinated illite/epoxy complex increased their flame retardant properties.

• Journal of the Korea Concrete Institute
• /
• v.13 no.2
• /
• pp.175-183
• /
• 2001

Immersion tests with artificial seawater were carried out to investigate the resistance to seawater attack of 5 types of cement matrices. From the results of compressive strength and length change, it was found that blended cement mortars due to mineral admixtures, were superior to portland cement mortars with respect to the resistance to seawater attack. Moreover, XRD analysis indicated that the peak intensity ratio of low heat portland cement(LHC) paste, in portland cement pastes, had better results, and so did that of blended cement Paste. Pore volume of pastes by mercury intrusion porosimetry method demonstrated that total pore volume of ordinary portland cement(OPC) paste had a remarkable increase comparing with that of other pastes. In case of immersion of artificial seawater, the use of ground granulated blast-furnace slag and fly ash, however, showed the beneficial effects of 56% and 32% in reduction of total pore volume, respectively.

• Journal of the Korea Institute of Building Construction
• /
• v.17 no.1
• /
• pp.15-21
• /
• 2017

WHO reported that millions of people die every year because of diseases induced from environmental pollution. In 2012, approximately 7 million people were killed due to air pollution. Major cause of such pollution includes toxin, chemical waste, radiation and air pollution. Therefore, the significance and interest to indoor air quality has been continuously increased. Especially, the interest in radon, the ARC group 1 carcinogen, is rapidly increasing, and banning the use of construction materials that release radon, repairing aged buildings, and developing ventilators. To reduce the level of radon gas was inflowed to indoors and outdoors, this study is to research and develop a radon gas absorption board using absorbents. The absorbents utilized to absorb the radon gas were porous diatomite, natural zeolite, 4A zeolite and 13X zeolite and employed bentonite and illite, montmorillonites with the property of exchanging anions. As the main binder, magnesium oxide was used, with a content of 25% magnesium chloride.

• Korean Journal of Food Science and Technology
• /
• v.23 no.3
• /
• pp.360-365
• /
• 1991

Effect of random interesterification on the physicochemical properties in blends of corn germ oil and fully hydrogenated soybean oil was studied. Interesterification by using 0.4% sodium methoxide at $80^{\circ}C$ was completed in 35 minutes as determined by HPLC analysis for triglyceride composition. Changes of melting point, solid fat content, crystal form, fatty acid and triglyceride composition was investigated. After the interesterification, melting point and solid fat content were decreased, and coarse and large crystals were modified to fine and uniform. Fatty acid composition was not altered but triglyceride composition was largely altered. Interesterified blends of corn germ oil and fully hydrogenated soybean oil made with 80%, 20% and 75%. 25%, respectively, had desirable characteristics of the margarine for home use.