• Title/Summary/Keyword: functional inorganic material

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Research trends of MXenes as the Next-generation Two-dimensional Materials (차세대 2차원 소재, MXenes의 연구 동향)

  • Lee, Hojun;Yun, Yejun;Jang, Jinkwang;Byun, Jongmin
    • Journal of Powder Materials
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    • v.28 no.2
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    • pp.150-163
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    • 2021
  • Interest in eco-friendly materials with high efficiencies is increasing significantly as science and technology undergo a paradigm shift toward environment-friendly and sustainable development. MXenes, a class of two-dimensional inorganic compounds, are generally defined as transition metal carbides or nitrides composed of few-atoms-thick layers with functional groups. Recently MXenes, because of their desirable electrical, thermal, and mechanical properties that emerge from conductive layered structures with tunable surface terminations, have garnered significant attention as promising candidates for energy storage applications (e.g., supercapacitors and electrode materials for Li-ion batteries), water purification, and gas sensors. In this review, we introduce MXenes and describe their properties and research trends by classifying them into two main categories: transition metal carbides and nitrides, including Ti-based MXenes, Mo-based MXenes, and Nb-based MXenes.

Improvement of Mechanical Properties of Epoxy Composites Using NH2-HNT Manufactured by Dry Coating Device as Filler (건식코팅장치를 이용하여 제조한 NH2-HNT를 충진재로 응용한 에폭시 복합체의 기계적 물성 향상)

  • Moon il Kim
    • Journal of the Korean Society of Industry Convergence
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    • v.27 no.2_2
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    • pp.371-375
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    • 2024
  • Epoxy resins are widely used in various fields due to their high adhesion, mechanical strength, and solvent resistance. However, as the volume decreases during the hardening process and the cooling process after hardening, stress is generated and when an external force is applied, the brittle material exhibits destruction behavior. To complement this, research has been conducted using inorganic nanofillers such as halloysite nanotube(HNT). HNT has a nanotube structure with the chemical formula of Al2Si2O5(OH)4·nH2O and is a natural sediment of aluminosilicate. It has been used as additive to improve the mechanical properties of epoxy composites with exchange of amine group as a terminal functional group. In order to simplify complicated procedures of common wet method, a dry coating machine was designed and used for amine group exchange in previous research. In this study, they were applied as filler in epoxy composites, and mechanical properties such as tensile strength and flexural strength of composites were examined.

The Study of Plate Powder Coated Nano Sized ZnO Synthesis and Effect of Sensory Texture Improvement (나노 ZnO 입자가 코팅된 판상 분체의 합성과 사용감 증진 효과에 대한 연구)

  • Jin-Hwa , Lee;Ju-Yeol, Han;Sang-Gil, Lee;Hyeong-Bae, Pyo;Dong-Kyu, Lee
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.30 no.2
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    • pp.173-180
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    • 2004
  • Nano sized ZnO particle as 20-30nm applies for material, pigments, rubber additives, gas sensors, varistors, fluorescent substance as well as new material such as photo-catalyst, sensitizer, fluorescent material. ZnO with a particle size in the range 20-30nm has provided to be an excellent UV blocking material in the cosmetics industry, which can be used in sunscreen product to enhance the sun protection factor and natural makeup effect. But pure ZnO particles application limits for getting worse wearing feeling. We make high-functional inorganic-composite that coated with nano-ZnO on the plate-type particle such as sericite, boron nitride and bismuthoxychloride. In this experiment, we synthesized composite powder using hydrothermal precipitation method. The starting material was ZnCl$_2$ Precipitation materials were used hexamethylenetetramine(HMT) and urea. We make an experiment with changing as synthesis factors that are concentrations of starting material, precipitation materials, nuclear formation material, reaction time, and reaction temperature. We analyzed composite powder's shape, crystallization and UV-blocking ability with FE-SEM, XRD, FT-IR, TGA-DTA, In vitro SPF test. The user test was conducted by product's formulator. In the results of this study, nanometer sized ZnD was coated regardless of the type of plate-powder at fixed condition range. When the coated plate-powders were applied in pressed powder product, the glaze of powder itself decreased, but natural make-up effect, spreadability, and adhesionability were increased.

Hydration-Setting Property of Slaked Lime and Artificial Zeolite Synthesized with Top Water Sludge (정수슬러지로 합성한 인공제올라이트와 소석회의 수화응결특성)

  • La, Jung-Min;Choi, Duk-Jin;Kim, Min-Gil;Kim, Jin-Man
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.5 no.4
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    • pp.122-128
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    • 2010
  • On the international provision on prohibition of ocean dumping of waste, tap water sludge has been buried or recycled on th low value added product as landfill. Due to the tap water sludge having high inorganic content, differing from the sewage sludge, it is possible to use as a usable resource by suitable process. We have studied on hydro thermal processing of tap water sludge with phosphoric acid and finally synthesize a artificial zeolite having a deodorization property. To use it as a building material, it has to be solidification. This study is on the properties of artificial zeolite synthsized and solidification properties by various types of solidifier. It is showed that the slaked lime is the best on setting property and its optimum content is 30-60 weight proportion. Solid by solidified by slaked lime has low strength and excellent deodorization performance, so it is possible to use as a functional pannel as gypsum board.

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Evaluation on the Muscular Strength Activity of Medicinal Herb Hot-Water Extracts (생약 열수추출물의 근력향상 효능 평가)

  • Lee, Chang-Ho;Kim, Young-Eon;Kim, In-Ho;Han, Dae-Seok;Seong, Ki-Seung;Yang, Dong-Heum;Song, Tae-Cheol
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.36 no.6
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    • pp.678-682
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    • 2007
  • Effects of medicinal herbs on the improvement of muscular strength along with the related fatigue factors were evaluated in SD rats. Nine types of treatment groups were fed diets supplemented with 1% herb hot-water extracts (Liriope spicata (LS), Schizandra chinensis (SC), Acanthopanax sessiliflorus (AS), Saliconia herbacea (SH), Eucommia ulmoides (EU), Lycium chinensis (LC), Panax ginseng (red ginseng) (PG), Polygonum multifloum (PM), Glycyrrhizae uralensis (GU)) for 4 weeks. The muscular strength of all groups were measured weekly for 4 weeks. After 4 weeks serum was collected and liver dissected out for the analysis of glycogen and fatigue factors. The liver glycogen contents of all treatment groups ($21.0{\sim}25.9mg/g$) were higher than that of control group (18.1 mg/g). A significantly increase of muscular strength in the fourth week were found in the AS (282.5 gf), SH (277.4 gf), PG (287.2 gf) groups (p<0.05). LS (7.88 mg/dL), SC (7.85 mg/dL), AS (7.64 mg/dL), EU (7.54 mg/dL), LC (7.81 mg/dL) and PG (7.75 mg/dL) groups were significantly reduced in serum inorganic phosphorus concentration measured after 4 weeks (p<0.05). Serum lactate levels of treatment groups ($8.61{\sim}12.18{\mu}g/dL$) were significantly lower than that of control group ($17.45{\mu}g/dL$). These results suggest that medicinal herbs enhanced muscular strength of rats by delaying accumulation of muscular fatigue factor.

Analysis of nutritional contents and useful functional materials for finding breeding resources in Flammulina velutipes (팽이 기능성 육종소재 발굴을 위한 영양성분 및 유용 기능성 물질 분석)

  • Ji-Hoon, Im;Minji, Oh;Youn-Lee, Oh;Min-Sik, Kim;Jong-Won, Lee
    • Journal of Mushroom
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    • v.20 no.4
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    • pp.218-226
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    • 2022
  • Flammulina velutipes, known as winter mushroom in the family of Physalacriaceae, is the main edible and export mushroom with the third highest production after oyster and king oyster mushroom in Korea. However, as normal consumers regard F. velutipes as a simple subsidiary material, there is a limitation to increasing mushroom demand. In order to overcome the consumption limit and increase the differentiation of new varieties, it is necessary to breed varieties with enhanced functionality in consideration of consumer preferences. Therefore, the study was performed to analyze nutrient components and several useful functional substances with 26 genetic resources of F. velutipes. Analyses of inorganic compound(Ca, K, Mg) and 15 amino acids revealed that Strain 4148 had the highest content among the 26 strains. Beta-glucan, which increases immune activity and polyphenol, which exert antioxidant effects were higher in non-white strains than in white strains with a small number of exceptions. Among the five fatty acids, linoleic acid(an omega-6 fatty acid) and α-linolenic acid(an omega-3 fatty acid), were detected in six mushroom strains. α-linolenic acid, which was not found in five major mushrooms including oyster mushrooms, was identified in F. velutipes. The results of HPLC analysis showed that 'Auram' (Strain 4232) and 'Baekseung'(Strain 4230) had the highest content of the stabilizing neurotransmitter GABA(15.38 ㎍/ml and 20.56 ㎍/ml, respectively) among non-white and white strains, respectively. Our findings provide useful information for breeding F. velutipes to obtain strains with enhanced functionality.

Grinding Kinetics of Calcite, Pyrophyllite and Talc During Stirred Ball Milling - Consideration of Selection Function (교반 볼밀에 의한 방해석, 납석, 활석의 분쇄 시 분쇄속도론에 관한 연구 - 선택함수의 고찰)

  • Choi, Hee-Kyu;Kim, Seong-Soo;Hwang, Jin-Yeon
    • Journal of the Mineralogical Society of Korea
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    • v.20 no.2 s.52
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    • pp.135-145
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    • 2007
  • The needs for the ultra fine particles have been increased in preparation field of raw powders such as fine ceramics and high functional products. In this study, a series of wet grinding experiments were carried out on inorganic powders such as calcite, pyrophyllite and talc by a stirred ball mill. The particle size distribution of ground products of each test material fur a given grinding time was found to be expressed by the grinding rate (selection function) which was obtained from the grinding kinetics analysis. The median diameter decreased from 6.49 to $0.47{\mu}m$ in calcite, and decreased from 3.91 to $1.14{\mu}m$ in pyrophyllite. However, in talc, median diameter was decreased a little bit from 10.30 to $6.67{\mu}m$. The grinding rate changing on calcite and pyriphyllite were similar at the same conditions. However, in the case of talc, it was observed that the grinding rate was not increased compared to other samples.

Bioavailability of Aspartic Acid Chelated Calcium in Calcium Deficient Rats (아스파르트산 킬레이트 칼슘의 칼슘 결핍쥐에서의 생물학적 유용성)

  • Park, Myoung-Gyu;Ha, Tae-Yul;Shin, Kwang-Soon
    • Journal of Nutrition and Health
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    • v.44 no.6
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    • pp.474-480
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    • 2011
  • Calcium (Ca) is an essential element to maintain body homeostasis. However, many factors disturb calcium absorption. Aspartic acid chelated calcium (AAC) was synthesized by new methods using calcium carbonate and aspartic acid. This study was carried out to investigate the bioavailability of AAC in Ca-deficient rats. The experimental groups were as follows: NC; normal diet control group, CD-C; untreated control group of Ca-deficient (CD) rats, CD-$CaCO_3$; $CaCO_3$ treated group of CD rats, CD-AAC; AAC treated group of CD rats, and CD-SWC; and seaweed-derived Ca treated group of CD rats. The Ca content of various types of Ca was held constant at 32 mg/day, and the four CD groups were fed for 7 days after randomized grouping. Ca content in serum, urine, and feces within feeding periods were analyzed to confirm Ca absorption. Serum Ca content was significantly higher in the CD-AAC (11.24 mg/dL) and CD-SWC (10.12 mg/dL) groups than that in the CD-C (8.6 mg/dL) group 2 hours following the first administration. The Ca content in feces was significantly lower in the CD-AAC (35.4 mg/3 days) and CD-SWC (71.1 mg/3 day) groups than that in the CD-$CaCO_3$ (98.7 mg/3 days) group (p > 0.05). AAC had a 2.3-fold higher absorption rate of Ca than that of SWC. No differences in fibula length were observed in the NC and CD groups. The fibula weights of the CD-AAC (0.33 g) and CD-SWC (0.33 g) groups increased compared to those in the CD-C (0.27 g) group; however, no significant difference was observed between the CD groups. We conclude that bioavailability of AAC is higher than that of seaweed-derived Ca or inorganic Ca. Thus, these findings suggest the AAC has potential as a functional food material related to Ca metabolism.

Investigation and Assessment of the Deterioration on Aging Large Water Mains (대형 상수관로 노후상태 조사 및 평가에 관한 연구)

  • Kim, Ju-Hwan;Bae, Chul-Ho;Kim, Jung-Hyun;Hong, Sung-Ho;Lee, Kyung-Jae
    • Journal of Korean Society of Water and Wastewater
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    • v.20 no.4
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    • pp.545-558
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    • 2006
  • The current conditions of large water mains are evaluated by deteriorations and the causes of deterioration are investigated through visual assessments in the field, mechanical tests and analysis of chemical compositions in laboratory for each pipe material, unlined cast iron pipes (CIPs), ductile iron pipes (DCIPs) and steel pipes (SPs) Tubercles and scales from internal and external corrosion of unlined cast iron pipes were identified as the causes of functional performance limitations in large water mains. It is investigated that main causes of internal and external corrosion of water pipes are from lots of depositions of organic and inorganic substances on pipe surface, concentrated pitting, and uniform corrosion by local or global exfoliation or detachment of lining and coatings of DCIPs and SPs. Internal and external corrosion depths of CIPs were higher than those of DCIPs and SPs. Consequently, total corrosion rate summed internal and external corrosion rates of CIPs also were shown to be higher than those of DCIPs and SPs. The failure time from hole generation of CIPs by total corrosion rate was predicted to be taken sixteen years, and DCIPs and SPs were twenty-six years and one hundred and fifty three years. And longitudinal deflection of investigated water mains were not happened and mechanical strengths such as tensile strength, elongation, and hardness also were mostly suited to Korea Standards. It was thought that the weakness of tensile strength of one sample(S-11) was, however, due to higher carbon contents(%) in CIPs. Pipe deterioration score of S-46 was 55.2 and was preferentially assessed to be rehabilitated.

Effect of 3-Isocaynatopropyl Triethoxy Silane on PU Adhesive (3-Isocaynatopropyl Triethoxy Silane이 PU 접착제에 미치는 영향)

  • Ju, Honghee;Jang, Euisub;Park, Chan Young;Lee, Won-Ki;Kim, Taekyun;Chun, Jae-Hwan
    • Journal of Adhesion and Interface
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    • v.14 no.1
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    • pp.36-42
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    • 2013
  • To improve hydrolytic stability of polyurethane (PU) adhesives, a silane coupling agent (SCA) was added. 3-Isocyanatopropyl triethoxy silane (ITS) as a SCA has two functional groups in the main chain and it is used to improve an interfacial interaction between polymer and inorganic material or metal. In this study, PU adhesives with different amounts of ITS from 0 to 1 wt% were synthesized. Pot time, modulus, thermal stablilty, and adhesive force of the obtained samples were measured. The results showed that the adhesives with ITS showed better properties than that of pure one.