• Restorative Dentistry and Endodontics
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• v.30 no.3
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• pp.149-157
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• 2005

Mechanical removals in decayed teeth have been performed using drill and sharp hand instruments. These methods have some disadvantages such as pain, local anesthesia and overextended cavities Therefore chemo-mechanical excavation of dentin carious lesions has been introduced. The purpose of this study was to evaluate the efficacy of traditional mechanical methods using burs and chemo-mechanical methods (Carisolv) of caries dentin. Mechanical caries removal was carried with low speed round bur Chemo-mechanical caries excavation was performed with Carisolv (Medi-team), using the Carisolv hand instruments. The mean time to remove caries with two different methods was evaluated and the data analyzed with SPSS software (ver 11.5) by t-test (p < 0.05). For histomorphometry of caries removal were also carried with mechanical or chemo-mechanical (Carisolv) methods from 20 extracted caries permanent molars. Complete caries removal was verified with a $\#$23 sharp explorers, Caries Detector (Kuraray Co. Japan), and standard apical radiography. 1. Chemo-mechanical method was taken more times than mechanical method (1.5 fold) (p < 0.05) 2. Excavation for caries took more time for molar lesion than premolar lesion, and the least time was taken to remove the caries in incisor lesion (p < 0.05). 3. There were no significant differences to remove the caries between the maxilla and mandible (p > 0.05). 4. The remaining carious dentin was detected after the ckemo-mechanical removal of the carious dentin, and no smear layer were seen after the mechanical and chemo-mechanical removal of the carious dentin.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2001.11a
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• pp.13-13
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• 2001

• Journal of the Korean Applied Science and Technology
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• v.37 no.5
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• pp.1100-1105
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• 2020

We investigated the driving force and the required charges for spontaneous reduction of metal nanoparticles (NPs) on a scotch tape induced by mechanochemical activation. The charges were analyzed based on anodic stripping voltammetry (ASV) of silver, which is proportional to the number of charge identities on the tape. The results supported that the driving force is mechanochemical radicals rather than ions in the light of the high charge density on the tape.

• The korean journal of orthodontics
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• v.29 no.4 s.75
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• pp.483-490
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• 1999

Interdental enamel stripping is an usual method for correction of abnormal tooth shape and tooth size discrepancy which is one of the etiologic factors of malocclusion. Clinically it Is useful to correct the minor crowding in anterior teeth and posterior occlusion during finishing stage of orthodontic treatment. But this procedure has risks such as irreversible tooth reduction and remaining roughness of enamel surface can accumulate plaque which can evoke periodontal problem. Even if various methods were introduced to minimize the enamel surface roughness, their evaluation was limited in morphologic differences by scanning electronic microscope(SEM). The purpose of this study was to compare the various interdental enamel stripping method by SEM and to quantify the difference of surface roughness by use of Surfcorder SEF-30D(Kosaka Lab. Ltd.) which can measure the roughness of surface. The stripping methods were divided into mechanical and mechanical-chemical method. Air-rotor stripping and separating strip were used for mechanical stripping and $37\%$ phosphoric acid was used for chemical stripping. The enamel surface roughness after mechanical or mechanical-chemical stripping of interproximal surfaces of premolars which were extracted for orthodontic purpose were measured and compared by means of SEM and $Surfcorder^{\circledR}$, the results were as follows. 1. Enamel surface of primary treated by coarse diamond bur and separating strip groups showed highest value of roughness. 2. To compare the primary treated groups between mechanical and mechanical-chemical method, the latter group showed lower value of roughness remarkably. 3. Mechanical stripping groups which were treated both coarse and fine instrument showed lower value of roughness as much as non treated group. 4. The use of Pumice for final polishing did not show significantly smoothening the stripped enamel surface any more.

• Journal of Powder Materials
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• v.11 no.2
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• pp.89-96
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• 2004

1980년대 후반부터 집중적으로 연구되어온 기계적 합금화 공정 기술은 이제 단순화합물 조성의 합금화공정 뿐 만아니라 기계화학적(Mechanochemical) 방법으로까지 진보되어 다양한 시스템으로의 응용기술로까지 발전하게 되었다 더욱이 최근 나노기술의 한고상 제조기술로서도 역할을 하게 되는 기계적 합금화 공정 기술은 21세기에 있어서도 본문에서 연급한 바와 같은 고온용 고장도 Al 합금제조 외에도 나노결정립 분말, 자성재료, 에너지전환/저장기능재료, 준결정상제어 분야로서의 무한한 응용 가능성을 기대해 볼 수 있다.

• Journal of Powder Materials
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• v.9 no.5
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• pp.329-335
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• 2002

Recently, the fabrication process of the W-Cu nanocomposite powders has been studied to improve the sinterability through the mechanical alloying and reduction of W and Cu oxide mixtures. In this study. the W-Cu composites were produced by mechanochemical process (MCP) using $WO_3-CuO$ mixtures with two different milling types of low and high energy, respectively. These ball-milled mixtures were reduced in $H_2$ atmosphere. The ball-milled and reduced powders were analyzed through XRD, SEM and TEM. The fine W-Cu powder could be obtained by the high energy ball-milling (HM) compared with the large Cu-cored structure powder by the low energy ball-milling (LM). After the HM for 20h, the W grain size of the reduced W-Cu powder was about 20-30 nm.

• Annual Conference on Human and Language Technology
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• 1989.10a
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• pp.10-14
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• 1989

한글문자를 기계화하기 위하여 로마문자로 표기하는 방법에 대한 새로운 제안을 한다. 현재 남한안이나 북한안은 서로 이견을 보이고 있어서 국제적 합의에 이르지 못하고 있다. 본 제안에서는 남, 북한 안과는 달리 영문자의 대문자와 소문자를 모두 활용하며 다양한 모음의 구성에서 음성학적으로 표기한다. 이 표기법은 자체의 합리성, 국제표준과의 호환성 판독의 편리성, 음성인식에의 이용성등에서 기존 표기체계보다 유리하다.

• Current Photovoltaic Research
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• v.4 no.3
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• pp.114-118
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• 2016

$Cu_{1.8}Zn_{1.2}(Sn_{1-x}Ge_x)S_4$ (CZTGeS) nanocrystals were mechanochemically synthesized from elemental precursor powders without using any organic solvents and any additives. The composition of CZTGeS nanocrystals were systematically varied with different Ge mole fraction (x) from 0.1 to 0.9. The XRD, Raman spectroscopy, high-resolution TEM, and diffuse reflectance studies show that the as-synthesized CZTGeS nanocrystals exhibited consistent changes in various structural and optical properties as a function of x, such as lattice parameters, wave numbers for $A_1$ Raman vibration mode, interplanar distances (d-spacing), and optical bandgap energies. The bandgap energy of the synthesized CZTGeS nanocrystals gradually increases from 1.40 to 1.61 eV with increasing x from 0.1 to 0.9, demonstrating that Ge-doping is useful means to tune the bandgap of mechanochemically synthesized nanocrystals-based kesterite thin-film solar cells. The preliminary solar cell performance is presented with an efficiency of 3.66%.

• Food Industry
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• s.121
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• pp.15-25
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• 1993

부수게는 찹쌀이 주원료인데 찹쌀의 수침은 다른 가공공정에서 볼 수 없는 장시간 수침을 실시함으로써 이 기간 동안 유기산의 생성을 유도하여 팽화도에 마이너스 영향을 주는 $Ca^{2+}$과 $Mg^{2+}$을 용출시켜 부수게의 팽화력증가를 유도하여 온 특이한 공정으로 이는 부수게 제조공정에서 미생물의 작용을 활용하여 온슬기를 엿볼 수 있다. 또 한가지 특징은 대두의 첨가는 단백질 함량을 증가시키는 의미도 있으나 찹쌀가루를 찔 때 대두에서 유래한 armylase가 전분에 작용하여 건조된 부수게 반대기의 결정화도을 낮게하여 건조 취급중 균열발생을 감소시키는 효과와 찧을 때 점성이 감소하는 효과가 있는 것으로 판단된다. 부수게 제조시 대두를 첨가하는 것은 영양성, 기능성에서 볼 때 우리가 창출한 쌀과 대두의 조화적 이용의 한예가 된다. 부수게는 우리가 흔히 먹고 있는 밥, 떡 죽처럼 상압에서 가수해서 호화한 것이 아니라 호화후 고온(170$^{\circ}C$)에서 팽화하여 다공성구조를 형성시키므로써 밥이나 떡에서 전혀 느낄수 없는 crunchy type의 snack성을 가지는 과자로써의 특성을 가지고 있다. 그 제조공정은 12단계 이상으로 복잡하며 제조원리면에서 볼 때 물리적, 화학적 그리고 미생물학적인 공정이 조화적으로 활용되어 만들어지고 있기 때문에 재현성이 낮은 어려움이 있기도 하다. 대량생산을 위해서는 적합한 기계화와 자동화공정이 선결되어야 하는 데 떡의 높은 점성이 기계화와 자동화에 큰 제한요인으로 남아 있고, 또한 부수게 반대기를 건조하는 동안 반대기의 균열(cracking)을 효과적으로 방지 할 수 있는 건조조건과 방법에 대한 연구가 남아 있다.

• Current Photovoltaic Research
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• v.5 no.4
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• pp.140-144
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• 2017

$CuSbS_2$ (CAS) and $CuSbSe_2$ (CASe) nanocrystals (NCs), which consist of earth-abundant elements, were synthesized by a mechanochemical method. Elemental precursors such as copper, antimony, sulfur, and selenium were used without adding any organic solvents or additives. The NCs were synthesized by milling for a few hours. The sudden phase changes occurred by self-ignition and propagation, as previously observed in other mechanochemical synthetic processes. The XRD, Raman, and TEM analysis were carried out to determine the crystallinity and secondary phase of the as-synthesized CAS and CASe NCs, confirming the phase-pure synthesis of CAS and CASe. Optical properties were investigated by UV-Vis spectroscopy and it was observed that the band gap energies were about 1.1 and 1.5 eV, respectively for CAS and CASe, suggesting the potential for the use as solar cell materials. The NC colloids dispersed in anhydrous ethanol were prepared and coated on Mo substrates by a facile doctor-blade method. The investigation on the solar cell properties of the as-synthesized materials is underway.