Core-shell 구조의 Au/TiO₂ 나노 미립자의 합성 및 특성 평가

유연태,Paul Mulvaney 한국세라믹학회 2003 한국세라믹학회지 Vol.40 No.9

Au/TiO$_2$ core-shell 구조 나노 미립자가 졸-겔법에 의해서 제조되었고, TiO$_2$ shell의 형상과 결정성이 TEM과 UV-Vis. absorption spectrometer에 의해서 조사되었다. Au/TiO$_2$ core-shell 나노 미립자는 Au 콜로이드 에탄올 수용액 중에서 TOAA(Titanium Oxide Acethylacetonate)의 가수분해에 의해 합성될 수 있었다. Au 나노 미립자의 표면에 형성된 TiO$_2$ shell의 두께는 약 1 nm이었다. TiO$_2$ shell의 결정성을 조사하기 위하여. TiO$_2$가 피복된 Au 콜로이드 에탄올 용액에 254 nm의 자외선과 $^{60}$Co의 방사선을 조사하였다. Au 나노 미립자의 surface plasmon 현상은 방사선이 조사되었을 때만 나타났고, 이 결과로부터 TiO$_2$ shell은 비정질 상태임을 알 수 있었으며, Au의 분산성 향상을 위해 표면에 처리된 MUA(Mercaptoundecanoic Acid)층은 전자의 이동을 방해하는 장애물로 작용하지 않음을 확인할 수 있었다. Au/TiO$_2$ core-shell structure nanoparticles were synthesised by sol-gel process, and the morphology and crystallinity of TiO$_2$ shell were investigated by TEM and UV-Vis. absorption spectrometer. Au/TiO$_2$ core-shell structure nanoparticles could be prepared by the hydrolysis of TOAA (Titanium Oxide Acethylacetonate) in Au colloid ethanol solution with $H_2O$. The thickness of TiO$_2$ shell on the surface of Au particles was about 1 nm. To investigate the crystallinity of TiO$_2$ shell, UV light with 254 nm and radioactive lay of $^{60}$ CO were irradiated on the TiO$_2$ coated Au colloid ethanol solution. The surface plasmon phenomenon of Au nanoparticles appeared only when the radioactive lay was irradiated on the TiO$_2$ coated Au colloid ethanol solution. From these results, it was found that the TiO$_2$ shell was amorphous and the MUA (Mercaptoundecanoic Acid) layer on the Au particle for its dispersion didn't act as an obstacle to disturb the movement of electron onto the surface of Au particle.

A Study on Survival and Growth of Ark shell, Scapharca broughtonii with differential density during hanging culture

오봉세,진영국,정춘구,임월애,김숙양 한국패류학회 2014 The Korean Journal of Malacology Vol.30 No.1

Ark shell Scapharca broughtonii length and total weight growth by density, which was hanging-cultured near the sea area of Yeosu-city, Hoenggan-island (below is Yeosu), showed inverse correlation with density. As for the average growth of shell length by density, the test area of 10 shells showed the best result as 5.21 mm, and it became lower as density became higher. Also, the increase of total weight by density showed the same result, thus on the whole, the increase of average shell length and total weight of 10-20 shell test area showed the better result than the test area of 30-40 shells. In addition, even if the parashell’s shell length by density and total weight growth in the sea area of Namhae-gun, Mijo-fishing port (below is Namhae) showed inverse correlation with density, it showed the slighter inverse correlation than the sea area of Yeosu. As for the average growth of shell length by density, the test area of 10 shells showed the best result as 4.55mm, but the average growth of shell length by density in the test area of 20-40 shells appeared to be similar as 3.11, 3.36 and 3.27 mm. On the other hand, as for the increase of total weight by density, the test area of 10-20 shells showed the more increase than the test area of 30-40 shells. In conclusion, it is guessed that the culture density of 20 shells/0.12 m2 (166 shells / 1 m2) would be appropriate when hanging-culturing the shells. At the sea area of A, the survival rate of Scapharca broughtonii parashell was 68-87% by density respectively, and it showed the density-dependent result, while the survival rate of sea area of Namhae, where phytoplankton as prey is abundant, showed the much better result as 91-100%. It is guessed that this may be due to the fact that the quantity of phytoplankton in sea area of Yeosu is just 55.89% of sea area of Namhae. When hanging-culturing the shells, the water temperature by sea area ranged from 16.22 to 25.66℃, salinity 30.07-33.48, pH 8.10-8.45, and DO 4.49-9.65 mg/L. 여수 횡간도 지역에서 밀도별 피조개 각장 과 전중량의 성장은 밀도와 역 상관관계를 보였다. 밀도별 각장 평균성장은10마리구가 5.21 mm로 가장 양호하였으며 밀도가 높을수록각장 성장은 낮아졌다. 밀도별 전중량의 증가도 같은 결과를보여 전반적으로 10-20마리구의 평균각장 및 평균 전중량의증가가 30-40마리구에 비하여 양호하게 나타났다. 남해해역에서 밀도별 피조개 각장과 전중량의 성장도 밀도와 역 상관관계를 보였으나 여수해역보다 약한 역 상관관계를보였다. 밀도별 각장 평균성장은 10마리구가 4.55 mm로 가장 양호한 결과를 보였으나, 20-40마리구의 밀도별 평균각장의 성장은 3.11, 3.36, 3.27 mm로 비슷하게 나타났다. 반면에 밀도별 전중량의 증가는 10-20마리구가 30-40마리구보다많았다. 결론적으로 피조개의 수하양성시 양성밀도는 20마리/0.12 m2 (166마리/1 m2) 가 적당하다고 사료되었다. 여수해역에서 피조개의 생존율은 밀도별로 각각 68%-87%, 로 밀도의존적 결과를 보였으나, 먹이생물인 식물플랑크톤이풍부한 남해해역의 생존율은 91%-100%로 월등히 양호한 결과를 보였는데, 이는 여수해역의 식물플랑크톤의 양이 남해해역의 55.89%에 불과하였기 때문이라 사료된다. 수하 양성 해역별의 수온범위는 16.22-25.66℃였고, 염분은30.07-33.48였으며, pH는 8.10-8.45범위였다. 그리고 용존산소 (DO) 는 4.49-9.65 mg/L 였다.

Composted Oyster Shell as Lime Fertilizer Is More Effective Than Fresh Oyster Shell

LEE, Young Han,ISLAM, Shah Md. Asraful,HONG, Sun Joo,CHO, Kye Man,MATH, Renukaradhya K.,HEO, Jae Young,KIM, Hoon,YUN, Han Dae Japan Society for Bioscience, Biotechnology, and A 2010 Bioscience, Biotechnology, and Biochemistry Vol.74 No.8

<P>Physio-chemical changes in oyster shell were examined, and fresh and composted oyster shell meals were compared as lime fertilizers in soybean cultivation. Structural changes in oyster shell were observed by AFM and FE-SEM. We found that grains of the oyster shell surface became smoother and smaller over time. FT-IR analysis indicated the degradation of a chitin-like compound of oyster shell. In chemical analysis, pH (12.3±0.24), electrical conductivity (4.1±0.24 dS m<SUP>−1</SUP>), and alkaline powder (53.3±1.12%) were highest in commercial lime. Besides, pH was higher in composted oyster shell meal (9.9±0.53) than in fresh oyster shell meal (8.4±0.32). The highest organic matter (1.1±0.08%), NaCl (0.54±0.03%), and moisture (15.1±1.95%) contents were found in fresh oyster shell meal. A significant higher yield of soybean (1.33 t ha<SUP>−1</SUP>) was obtained by applying composted oyster shell meal (a 21% higher yield than with fresh oyster shell meal). Thus composting of oyster shell increases the utility of oyster shell as a liming material for crop cultivation.</P>

Smart shell membrane prepared by microfluidics with reactive nematic liquid crystal mixture

Heo, In-Seok,Park, Soo-Young Elsevier 2017 Sensors and actuators. B Chemical Vol.251 No.-

<P><B>Abstract</B></P> <P>Smart, uniform-sized, solid-state nematic liquid crystal (NLC) (NLC<SUB>solid</SUB>) shell membranes were successfully fabricated from a reactive mesogen mixture (RMM727) and 4-cyano-4′-pentylbiphenyl (5CB) using a microfluidic method that combines flow-focusing and co-flow glass capillary geometries after UV curing and 5CB extraction. The NLC shells having planar anchoring with poly(vinyl alcohol) (NLC<SUB>p</SUB> shells) showed unavoidable defects as per the Poincaré theorem, with a total of +2 defect strengths on the top of the shell (often the weakest point of the shell), and were usually ripped during UV curing. The NLC shells having homeotropic anchoring with sodium dodecyl sulfate/polysorbate 80 (1/1, w/w) (NLC<SUB>h</SUB> shells) had a defect-free structure and could be formed into NLC<SUB>solid</SUB> shells without ripping when the density of the RMM727/5CB mixture matched that of the aqueous medium in the microfluidic channel (controlled using a glycerol/water mixture). The thin part of the NLC<SUB>h</SUB> shell was easily ripped during UV curing without density matching. The thus-produced NLC<SUB>solid</SUB> shells exhibited good swelling/shrinkage properties depending on the solvent quality and temperature, which could be further utilized for encapsulating/releasing Rhodamine 6G in/from the core of the NLC<SUB>solid</SUB> shell. The pores in the NLC<SUB>solid</SUB> shell (the size of which was controlled by the 5CB content of the RMM727/5CB mixture) were completely closed in a poor solvent and open in a good solvent. The encapsulation/release properties were studied based on the fluorescence intensity of encapsulated Rhodamine 6G. This study provides a method for preparing uniform-sized and robust NLC<SUB>solid</SUB> shell membranes that can be used for several applications, such as in smart actuators, sensors, and parts of microelectromechanical systems.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Uniform-sized nematic liquid crystal (NLC) solid shell membranes were fabricated from a reactive mesogen mixture using microfluidics. </LI> <LI> The conditions for the successful production of the NLC solid shells are homeotropic anchoring and density matching. </LI> <LI> The produced NLC solid shells exhibited good swelling/shrinkage properties depending on the solvent quality and temperature. </LI> <LI> The pores in the NLCsolid shell were completely closed in a poor solvent and open in a good solvent. </LI> <LI> This study provides a method for preparing uniform-sized and robust NLC solid shell membranes. </LI> </UL> </P>

Ni-YSZ Core-shell에서 Shell의 두께에 따른 SOFC의 출력특성

최병현,홍선기,지미정 한국수소및신에너지학회 2017 한국수소 및 신에너지학회논문집 Vol.28 No.6

SOFC anode fabricated core-shell using machano-fusion method using core with submicron size Ni, nano size YSZ for shell. Using prepared core-shell, depending on the thickness of the shell, we studied how the characteristics of sintering and SOFC cell change by sintering the anode. The Ni-YSZ core-shell has a Ni core of 0.5 to 1.2 μm over 2 to 7 YSZ of 15 to 20 nm is, and as the high speed mixing time increases, the YSZ number increases and the shell thickness becomes uniform increased. When the fuel electrode is manufactured with core-shell, it has superior sintering property, has grain of uniform size compared with the one synthesized by general mixing, the falling path is short, the conductors (electrons and ions) connection is excellent, the electrical conductivity has become excellent. The thicker the shell, the lower the electrical conductivity. When the thickness of shell ranged from 46 to 139 nm and 61 to 81 nm, the performance was the highest and the ASR was the smallest.

알킬 아크릴레이트와 관능성 단량체계 다중 Core-Shell 복합입자의 제조

최성일 ( Sung Il Choi ),조대훈 ( Dae Hoon Cho ),설수덕 ( Soo Duk Seul ) 한국접착및계면학회 2013 접착 및 계면 Vol.14 No.1

Core 입자로 methyl methacrylate (MMA), ethyl methacrylate (EMA)를 사용하고 shell 입자로 MMA, EMA, 2-hydroxyl ethyl methacrylate (2-HEMA), glycidyl methacrylate (GMA) 및 methacrylic acid(MAA)를 각각 사용하여 개시제 ammonium persulfate (APS), 유화제로 sodium dodecyl benzene sulfonate(SDBS)의 농도(0.01∼0.03 wt%), 단량체의 종류와 조성을 변화시켜 수용성 유화중합으로 다중 core-shell복합입자를 제조하여 전환율, 입자경 및 입도분포, 평균분자량, 분자구조, 유리전이온도, 플라즈마 처리후의 접촉각, 등온열분해속도 및 인장강도를 각각 측정하여 다음과 같은 결론을 얻었다. SDBS농도 0.02 wt%에서 MMA core-(EMA/GMA) shell 복합입자의 전환율이 98.5%로 우수하였고, 입자직경은 SDBS 농도 0.03 wt%에서 EMA core-(MMA/GMA) shell의 복합입자가 0.48 μm로 높게 나왔다. 유리전이온도 측정으로부터 공중합체는 1∼2개의 전이곡선 그리고 다중 core-shell 복합입자는 3개의 전이곡선을 얻었다. 전체적으로 접착박리강도의 크기는 shell 단량체가 MMA core인 경우 EMA/MAA >EMA/2-HEMA > EMA/GMA의 순으로 되었다. Multi core-shell composite particles were prepared by the water-born emulsion polymerization of various core monomers such as methyl methacrylate (MMA), ethyl methacrylate (EMA) and shell monomers such as MMA, EMA, 2-hydroxyl ethyl methacrylate (2-HEMA), glycidyl methacrylate (GMA) and methacrylic acid (MAA) in the presence of different concentrations of sodium dodecyl benzene sulfonate (SDBS). The following conclusions are drawn from the conversion, particle size and distribution, average molecular weight, molecular structure, glass transition temperature with DSC, contact angle after plasma treatment, tensile strength and isothermal decomposition kinetics. In the case of the concentration of 0.02 wt% SDBS, the conversion of MMA core-(EMA/GMA) shell composite particles was excellent as 98.5%. In the case of the concentration of 0.03 wt% SDBS, the particle size of EMA core-(MMA/GMA) shell composite particles was high as 0.48 μm. We confirmed that 3 points of glass transition temperatures appear for multi core-shell composite particles compared to 1~2 points of glass transition temperatures appear for general copolymer particles. Overall, the adhesion strength of shell composite particles was in the order of EMA/MAA > EMA/2-HEMA > EMA/GMA.

Yttrium이 첨가된 BaTiO₃에서 형성된 core/shell 구조에서 shell의 TCC 거동: 독립적 관찰

전상채,Jeon, Sang-Chae 한국결정성장학회 2020 한국결정성장학회지 Vol.30 No.3

MLCC(Multi-Layer Ceramic Capacitor)의 유전체 층에 사용되는 BaTiO₃ 입자는 안정한 TCC(Temperature Characteristics of Capacitance) 거동을 갖기 위해 core/shell 구조를 갖는다. 지금까지 shell의 특성은 core/shell 구조의 전체 특성에서 유추해 왔다. 이는 core/shell 구조가 겨우 수 ㎛의 작은 크기로 shell 특성만 구별해서 측정하기가 어렵기 때문이다. 본 실험에서는 micro-contact법을 이용하여 확산쌍 시편의 계면에 형성된 확대된 core/shell 구조에 Pt 전극을 증착하여 35~135℃ 에서 shell 영역의 독립적인 TCC 거동을 측정하였다. 그 결과, 65℃에서 최대 유전율 값을 갖는 완만한 피크의 확산 상전이(Diffusion Phase Transition) 거동인 core의 특성과 구별되는 거동을 관찰하였으며, 이는 core/shell 구조의 온도-유전거동을 묘사하는 모델링에서 실험 자료로 활용될 것으로 본다. Grains in the BaTiO₃, which is used for a dielectric layer in MLCC(Multi-Layer Ceramic Capacitor) are necessary to form core/shell structure for a stable TCC(Temperature Coefficient of Capacitance) behavior. The shell property has been deduced from the whole TCC behavior of core/shell structure due to its tiny size, ~ few ㎛. This study demonstrates the individual TCC behavior of the shell phase measured by micro-contact measurement in a temperature range between 35 and 135℃. Pt electrode pairs deposited on an enlarged core/shell structure in a diffusion couple sample made the measurement possible. As a result, the DPT (Diffusion Phase Transition) behavior of the shell phase was revealed as a different TCC behavior from that of the core: a broad peak with T_m at 65℃. This would be also useful experimental data for a modelling that depicts dielectric-temperature behavior of core/shell structure.

신석기시대 부산지역 거주자의 수산물 소비 실태

김진백 한국해양수산개발원 2019 해양정책연구 Vol.34 No.2

This study investigated what kinds of seafoods Busan residents in the Neolithic Age consumed. The remnants of consumption by Busan residents were left behind in many places. Foodstuff scraps were largely thrown into the shell mounds. Therefore, this study investigated their seafood consumption through natural and artificial remains in the shell mounds. There were differences among identified seafoods by the types of the shell mound. That is, red sea breams, cods, sharks, and tunas accounted for majority of the remains of fishes identified from the open sea shell mounds. But in the identified fishes of the bay shell mounds, the remains of sea bass and cod accounted for a large portion. Only cod was identified as a main fish remain in both types of the shell mounds. This finding is caused by Liman Current. Cods migrate along with Liman Current and pass through the coast of Busan in winter. But the non-redundant species of fish are the result from reflecting the locational characteristics of the corresponding shell mound. Most natural remains of the shell mounds are shells. This fact tells us that shellfish was the main seafood consumed by Busan residents of the Neolithic Age. But, depending on the types of the shell mound, there are differences in the kinds of identified shells. For example, mussel, turban shell, and oyster were largely unearthed in the open sea shell mounds. But in the bay shell mounds, only oyster shells were largely unearthed. It is due to the habitat of the shellfish. The consumption status of seafoods in Busan during the Neolithic Age was examined for seasonal consumption by the type of seafoods, i.e., fishes, shellfish, and so on. And this study looked at the importance of seafood in terms of calorie and availability as foodstuff. The availability of seafood as foodstuff was examined in detail in terms of fishing quantities, fishing tools, fishing hours, and cooking methods. 본 연구는 신석기시대 부산지역 거주자들의 수산물 소비 실태를 조사한 것이다. 신석기시대의 소비 흔적들은 패총의 유물로 잔존하는 것이 대부분이다. 따라서 부산지역의 주요 패총 유물 중에서 수산관련 유물들을 대상으로 당시 소비되었던 수산물을 조사하였다. 그 결과, 외해형과 내만형 패총 지역의 수산 유물에 차이를 보임으로써 지역적 소비 수산물의 주종에 차이가 있음을 확인할 수 있었다. 또한 수산물의 식량자원으로써의 가치를 파악하기 위해 열량, 어획량, 어구, 어로시간, 조리방법 등을 중심으로 그 타당성을 살펴보았다..

Aqueous-phase synthesis and color-tuning of core/shell/shell inorganic nanocrystals consisting of ZnSe, (Cu, Mn)-doped ZnS, and ZnS

Choi, Jongwan,Yoon, Sujin,Kim, Felix Sunjoo,Kim, Nakjoong Elsevier 2016 JOURNAL OF ALLOYS AND COMPOUNDS Vol.671 No.-

<P><B>Abstract</B></P> <P>We report synthesis of colloidal nanocrystals based on ZnSe core, (Cu,Mn)-doped ZnS inner-shell, and ZnS outer-shell by using an eco-friendly method and their optical properties. Synthesis of core/shell/shell nanocrystals was performed by using a one-pot/three-step colloidal method with 3-mercaptopropionic acid as a stabilizer in aqueous phase at low temperature. A double-shell structure was employed with inner-shell as a host for doping and outer-shell as a passivation layer for covering surface defects. Copper and manganese were introduced as single- or co-dopants during inner-shell formation, providing an effective means to control the emission color of the nanocrystals. The synthesized nanocrystals showed fluorescent emission ranging from blue to green, to white, and to orange, adjusted by doping components, amounts, and ratios. The photoluminescence quantum yields of the core/doped-shell/shell nanocrystals approached 36%.</P> <P><B>Highlights</B></P> <P> <UL> <LI> ZnSe/ZnS:(Cu,Ms)/ZnS core/(doped)shell/shell nanocrystals were synthesized in an aqueous phase. </LI> <LI> Emission color of nanocrystals was controlled from blue to white to orange by adjusting the atomic ratio of Cu and Mn co-dopants. </LI> <LI> Photoluminescence quantum yields of the colloidal nanocrystals approached 36%. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

국내산 굴 패각의 광물학적 화학적 특성

하수현,김영규,차민경,김강주,김석휘 한국광물학회 2017 광물과 암석 (J.Miner.Soc.Korea) Vol.30 No.4

We investigated the mineralogical and chemical characteristics of oyster shell as thepossible substitute for the limestone used as an absorbent of SO2 gas. The oyster shells from Taeanand Tongyeong were used for the comparison with limestone and those from Boyreong and Yeosuwere additionally investigated. XRD results show that all shells are composed of calcite with theexception of the myostracum layer attached to adductor muscle and ligament, which is composed of aragonite. The marine sediments as impurities exist on the surface of shells or as inclusions in theshells. Calcite is the main mineral composition of the shell of barnacle which is also one of theimpurities. The oyster shell is composed of three main layers; prismatic, foliated, and chalk. The oystershell from Tongyeong with the largest shell size, has the smallest thickness of prismatic and foliatedlayers which contain protein called conchiolin, whereas that from Taean with the smallest shell sizehas the largest prismatic and foliated layers. The sizes of those two layers of the shells from Boryeongand Yeosu are larger than that from Tongyeong but smaller than Taean. Those differences aresupposed to be due to the different growth environments because the oysters from Tongyeong arecultured under the sea while those from Taean are in the tidal zone. The oyster shells generally showhigher amount of sulfur and phosphorus than limestone, mainly due to the composition of protein. Some elements such as Mg show significant variations in different layers. As for trace elements, Lishows much higher amount in oyster shells than limestone, suggesting the influence of the compositionof the sea water on the formation of the oyster shells. SO2 가스 반응제로 사용되는 석회석의 대체 가능 물질로서 굴 패각의 광물학적 화학적 특성을알아보았다. 생장환경에 따른 굴 패각의 특성을 파악하기 위하여 태안지역 및 통영지역의 굴 패각을석회석과 비교하였고 추가로 보령 및 여수 지역의 굴 패각을 연구하였다. XRD 분석 결과 굴 패각은아라고나이트로 구성되어 있는 폐각근 접합 부분 및 인대(ligament) 접합부분을 제외하고 방해석으로구성되어 있으며 불순물로서 나타나는 해양 퇴적물이 패각 내 표면에 존재하거나 일부 패각 내 포유물 형태로 나타나기도 했다. 불순물 중 하나인 패각 표면의 따개비의 경우도 방해석으로 이루어져 있어 소성에 영향을 주지는 않을 것으로 판단된다. 현미경 관찰을 통하여 굴 패각의 미세구조를 파악할수 있었다. 패각은 크게 각주층, 진주층, 초크층으로 구성되어 있는데 패각이 가장 큰 통영 굴 패각은콘키올린(conchiolin)이라 불리는 단백질을 일부 함유하는 각주층과 진주층의 두께가 가장 작았으며작은 크기의 태안 굴 패각의 경우 각주층과 진주층 두께가 가장 두꺼운 것으로 나타났다. 중간 크기의패각 크기를 갖는 보령과 여수 굴 패각은 그 층들이 두 패각의 중간정도의 두께를 보여주었다. 이는계속 바닷물 속에서 양식하는 통영과 조간대에서 공기와 바닷물 속에서 양식하는 태안의 생장 환경차이로 판단된다. 굴 패각들은 석회석과 달리 상대적으로 높은 인과 황 함량을 보여주는데 이는 패각내의 단백질에 의한 것이며 패각을 구성하고 있는 세 개의 층은 Mg 함량을 포함하여 일부 상이한 화학성분을 갖고 있기도 했다. 미량성분의 경우 패각의 경우 석회석 보다 Li의 함량이 상대적으로 많았으며 이는 바닷물 성분의 영향을 받았을 것으로 생각된다. 각 산지별 패각에서는 Zn의 함량 변화가가장 커서 Zn의 함량은 생성환경에 가장 영향을 많이 받는 미량원소로 판단된다.