Composites of carbon quantum dots (CQDs) are important materials to utilize the optical properties of CQDs in diverse applications including photoluminescence-based sensing and LED phosphors. Combining pre-prepared CQDs with a polymeric matrix usually causes changes in the optical properties of CQDs due to unavoidable aggregation. Recently, the preparation of composites based on in-situ formed CQDs has been debated to overcome the aggregation limits of the conventional mixing methods. Herein, we have demonstrated the synthesis of homogeneous CQDs composites by simple thermal annealing blends of aluminum hydroxide (AlOH), citric acid (CA), and urea (URA). Transmission electron microscopy (TEM), X-ray diffraction, and Raman spectroscopy studies revealed the formation of individual CQDs with a diameter of about 2–9 nm dispersed homogeneously over the AlOH matrix. The composites have a broad excitation band centered at about 360 nm and exhibit excitation-dependent photoluminescence which was similar to that of hydrothermally synthesized CQDs from CA and URA. The photoluminescent intensity of the composite was stable to UV irradiation and responded selectively to Cu(II) ion demonstrating its potential application in Cu(II) sensing.

폴리스티렌계 음이온교환막은 제조가 쉽고 공정이 간단한 장점을 갖고 있으나 막의 취성이 높아 내구성이 떨어지 는 단점을 가지고 있다. 이를 보완하여 유연하고 우수한 내구성을 갖는 막을 만들기 위해 acrylonitrile-butadiene rubber를 첨 가제로 사용하여 음이온교환막을 제조하였다. 다양한 조성의 vinylbenzylchloride와 styrene, divinylbenzene, acrylonitrile- butadiene rubber 그리고 benzoyl peroxide로 이루어진 단량체 용액을 지지체인 직물 형태의 지지체인 poly(propylene)위 에 캐스팅 후 열중합 가교시킨 다음 trimethylamine과 acetone을 이용하여 음이온 교환기(-N+(CH3)3)를 함유하는 복합막을 제 조하였다. 음이온 교환막 제조시 첨가제의 함량에 따른 막의 성능을 평가하여 최적화 비율을 찾고, 단량체의 함량을 변화하여 함수율, 이온교환용량(IEC) 및 전기저항 값을 측정하였다. 그 결과 최적화 비율로 제조된 막들은 아스톰사의 상용화 음이온 교환막(AMX)보다 높은 IEC와 낮은 전기저항 값을 나타내는 동시에 유연성과 내구성이 우수한 막이 만들어진 것을 확인할 수 있었다.

Multi-walled carbon nanotube (MWNT)/SnO2 nano-composite (MSC) for the anode electrode of a Li-ion battery was prepared using a homogeneous precipitation method with SnCl2 precursors in the presence of MWNT. XRD results indicate that when annealed in Ar at 400˚C, Sn6O4(OH)4 was fully converted to SnO2 phases. TEM observations showed that most of the SnO2 nanoparticles were deposited directly on the outside surface of the MWNT. The electrochemical performance of the MSC electrode showed higher specific capacities than a MWNT and better cycleability than a nano-SnO2 electrode. The electrochemical performance of the MSC electrode improved because the MWNT in the MSC electrode absorbed the mechanical stress induced from a volume change during alloying and de-alloying reactions with lithium, leading to an increase in the electrical conductivity of the composite material.

This study includes an analytical investigation of a composite beam consist of concrete, structural tees, and the reinforcement steel. The plastic hinge length theories are applied to this composite beam to calculate maximum deflection exactly. This composite beam can reduce the floor height compared with the reinforced concrete structure with same internal force. To calculate maximum deflection, we used plastic hinge length suggested by Corley, Sawyer and Mattock. Later, the experimental investigation should be performed to find out the plastic hinge length exactly.