Nam-Kyu Lee

Camouflage is a method evading predators in nature by assimilating into the environment. To realize an artificial camouflage surface for displays and sensors, many researchers have introduced several concepts including a metamaterial-selective absorber/emitter (MSAE). When an MSAE is adopted for camouflage at infrared (IR) wave, the energy dissipation of reduced emitting energy, as well as the reduction of emitting energy to deceive the IR signature from the surface, must be considered from the

Abstract Light, heat, and waves in electromagnetic energy are the foundation for the advancement of human being. Camouflage materials based on metamaterials are used to excel the performance limits by manipulating the electromagnetic energy. However, multispectral camouflage materials with flexibility are difficult to fabricate because required radiative properties in each spectral regime are different and have largely different scales of the unit cell in a single structure. The authors propose

Artificial camouflage surfaces for assimilating with the environment have been utilized for controlling optical properties. Especially, the optical properties of infrared (IR) camouflage materials should be satisfied with two requirements: deception of IR signature in a detected band through reduced emissive energy and dissipation of reduced emissive energy for preventing thermal instability through an undetected band. Most reported articles suggest the reduction of emissive energy in the detect

Camouflage refers to a creature's behavior to protect itself from predators by assimilating its signature with the environment. In particular, thermal camouflage materials in the infrared (IR) wave are attracting interest for energy, military, and space applications. To date, several types of camouflage materials such as photonic crystals and metal-dielectric-metal structures have been developed. However, flexible camouflage materials still face challenging issues because of the material's britt

In recent years, there has been increasing interest in the development of micron-scale devices utilizing thermal gradients to manipulate molecules and colloids, and to measure their thermophoretic properties quantitatively. Various devices have been realized, such as on-chip implements, micro-thermogravitational columns and other micron-scale thermophoretic cells. The advantage of the miniaturized devices lies in the reduced sample volume. Often, a direct observation of particles using various m

with a concentration exhibiting a minimum at about one mole per kg of solvent. The depth of the minimum decreases with increasing temperature and shifts slightly towards higher concentrations. We compare the experimental data with published data and apply a recent model based on overlapping hydration shells. Additionally, we calculate the ratio of the phenomenological Onsager coefficients using our experimental results and published data to calculate the thermodynamic factor. Simple linear, quad

Gas turbines require high power density for applications like aircraft and future mobility. Increasing operating temperature, particularly turbine inlet temperature, boosts performance. However, conventional cooling methods limit this increase. Selective laser melting (SLM) offers a promising avenue for realizing advanced cooling configurations beyond conventional fabrication techniques. However, unexpected defects in the final product can occur, making pre-fabrication quality estimation difficu