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Heteroatom doping into metal oxides advantageously modulates optoelectronic properties and provides promising possibilities for efficient light-to-energy conversion. Herein, nitrogen-doped ceria (N-CeO2) nanoparticles are prepared and then coupled with nitrogen-doped graphene (N-Gr) to create an active and long-lasting N-CeO2/N-Gr heterocatalyst. Optoelectronic features of N-doping materials (e.g., plasmon) are significantly improved toward the visible-light region, particularly for 3.9% N-CeO2/N-Gr nanocomposites. Namely, the 3.9% N-CeO2 possesses numerous catalytic active defects (N states, oxygen vacancy, and Ce3+ species), leading to a narrow bandgap energy and to the improved plasmonic properties of the ceria host, while the N-Gr preferably serves as an electron scavenger to collect plasmon-generated hot electrons migrating from 3.9% N-CeO2 to drive photocatalytic reactions under the irradiation of visible-light. Resultantly, the 3.9% N-CeO2/N-Gr photocatalyst delivers an impressive hydrogen evolution reaction (HER) rate of 3.7 μmol mgcat−1 h−1 under visible-light, which is 2.0- and 8.2-fold greater than those obtained from 3.9% N-CeO2 and CeO2 ones, respectively. Additionally, the combination of 3.9% N-CeO2 and N-Gr synergistically produces a long-lasting plasmonic HER photocatalyst system. Metal-free plasmonic N-doped oxides supported by N-doped graphene pave a promising pathway for efficient light-to-hydrogen fuel production accordingly.

The long-term goal of the Penning trap system for the heavy ion accelerator named RAON in Korea is to obtain an order of magnitude higher mass accuracy for short-lived rare isotopes. For that purpose, we are developing a sympathetic cooler for highly charged ions by exploiting laser-cooled Ca+ ions. We installed a prototype octagon chamber with a calcium atom source, a Paul trap, and a helical resonator for the high-voltage RF supply. The laser system is composed of three extended cavity diode lasers (423, 397, 866 nm) plus one UV diode laser (375 nm). The optical frequency stabilization setup is made up of a wavelength meter, a multichannel fiber switch and a PXI system with an 8-channel analog output module. After having obtained a resonant ionization signal from the calcium atomic beam, we applied the RF voltage to the trap electrodes and illuminated the cooling lasers at the center of the trap. We successfully observed a laser-cooled ion bunch and a linearly aligned ion string by using imaging optics and an electron multiplying charge coupled device (EMCCD) camera. In addition to the experimental effort, we performed a simulation study for cooling 132Sn10+ ions inside a laser-cooled 40Ca+ Coulomb crystal by using a parallel computation technique.

Highly sinterable Yb:Lu2O3 nano-powders without hard agglomeration were synthesized via a highly efficient spray co-precipitation method. The effects of the spray speeds on morphology and composition of the powders were investigated. The results showed that the composition and dispersion of precursor powders changed with the spray speed. When the spray speed reached 40 mL/min, the particles were spherical and showed higher uniformity. The pure phase Yb:Lu2O3 powder was obtained after calcining at 1000 °C for 2 h. The calcined powders were ball milled and dry-formed to prepare green body. Then the Yb:Lu2O3 transparent ceramic was fabricated by vacuum sintering at 1500 °C for 8 h and further hot isostatic pressing in an argon atmosphere.. The in-line optical transmittance of Yb:Lu2O3 transparent ceramic reached 82.05%@1000 nm and 81.08%@400 nm, respectively, and it had submicron level average grain size, which is an effective way to improve the optical properties of the transparent ceramic.

microRNA plays an important role in the development of tumors, including osteosarcoma. However, the role of miR-1225-5p in osteosarcoma is currently unclear. First, we found that miR-1225-5p was downregulated in osteosarcoma cells relative to its levels in normal bone tissue by analyzing GSE28423 data in the GEO database. Using GSE39040, we found that low miR-1225-5p expression is associated with poor prognosis in patients with osteosarcoma, and we also found low miR-1225-5p expression in patients with recurrent osteosarcoma. We later demonstrated that osteosarcoma cell lines transfected with miR-1225-5p mimic had decreased ability to proliferate, migrate, and invade relative to control cells. To elucidate the mechanism by which miR-1225-5p inhibits the development of osteosarcoma, we identified Sox9 as a target gene of miR-1225-5p using the TargetScan website. We confirmed that Sox9 is the target gene of miR-1225-5p using the luciferase reporter assay. We then found that Sox9 is highly expressed in osteosarcoma by analyzing the GSE16088 and GSE42352 datasets and that high expression of Sox9 is associated with poor prognosis in patients with osteosarcoma using the R2 database. Further analysis using the TARGET database uncovered that high Sox9 expression is associated with a high recurrence rate in patients with osteosarcoma. Transfection of Sox9 siRNA inhibited the proliferation, migration, and invasiveness of osteosarcoma cells. We transfected miR-1225-5p together with Sox9 siRNA into osteosarcoma cells, observing strong inhibition of proliferation, migration, and invasiveness. Finally, exogenous expression of Sox9 partially reversed the anticancer effects of miR-1225-5p in osteosarcoma cells. Taken together, our findings suggest that miR-1225-5p functions as a tumor suppressor in osteosarcoma by targeting Sox9, thereby revealing new therapeutic targets for osteosarcoma.

NAND flash memory is widely used as a cost-effective storage with high performance [1–2]. This paper presents a 128Gb multi-level cell (MLC) NAND flash memory with a 150 cells/string structure in 14nm CMOS that can be used as a cost-effective storage device. This paper also introduces several approaches to compensate for reliability and performance degradations caused by the 14nm transistors and the 150 cells/string structure. A technique was developed to suppress the background pattern dependency (BPD) by applying a low voltage to upper word lines (WLs) - the drain side(SSL side) WLs with respect to the location of the selected WL - during the verify sequence. Two techniques are also used to improve the program performance: equilibrium pulse scheme and smart start bias control scheme (SBC) in the MSB page. In addition, the first cycle recovery (FCR) of read enable (RE) and the bi-directional data strobe (DQS) is used to achieve a high speed I/O rate. As a result, a 640µs program time and a 800MB/s I/O rate is achieved.

Electron scattering mean free paths in fused silica and optical fiber preforms were measured for electric fields less than 5×104 V/cm. This was done by fitting the measured photo-injected current as a function of applied voltage to a current–voltage model which takes the effects of scattering in the image force potential well and barrier lowering into account. The mean free paths measured from positive (negative) bias voltage in fused silica and optical fiber perform cladding and core (20 mol % GeO2) are 29±2 A (29±2A), 40±3 A (41±2A) and 39±2 A (53±6A), respectively.

Novel capacitor technologies for high density FRAM device with 0.18 μm D/R (design-rule) have been researched and developed. In order to realize the high-density FRAM device with 0.18 μm D/R, the PZT film was modified by changing Zr/Ti composition and by using PTO seeding layer. Therefore, the crystallization temperature of the PZT film could be successfully lowered to 550°C. The remnant polarization of PTO-used 100 nm thick PZT capacitors measured at 2.7 V was approximately 24 μC/cm 2 , that is 30% higher than that of the PTO-unused PZT capacitors. Necessarily, as the PZT thickness and crystallization temperature are lowered, the thickness of bottom electrode can be reduced as well. Furthermore, by lowering the PZT crystallization temperature and by applying robust TiAlN oxidation barrier, low (300 Ω/contact) and stable contact resistance in a very small size of BC could be obtained. Finally, we successfully developed a capacitor stack height of 270 nm. The capacitor size was 0.26 × 0.44 μm2 and remnant ...

Dependence of optical trapping force on the trap depth is examined by calculating the intensity distribution of light focused through two media with different refractive indices. The optical trapping forces on the microsphere in the ray optics regime were measured as a function of the trap depth. As the trap depth decreased, the optical trapping force increased. These results are useful for designing a chamber to trap particles with a low-power laser and for explaining the inconsistency among the reported experimental results.

Effects of the PbTiO 3 (PTO) seeding layer on lowering the PZT crystallization temperature and reducing the capacitor stack height, especially PZT thin film, were systematically investigated. For these purposes, PZT film was modified by using the PTO seeding layer. By using the PTO seeding layer; the crystallization temperature of the PZT film was successfully lowered to 550°C. And remanant polarization of PTO-used 100nm thick PZT capacitors measured at 3V was approximately 23 w C/cm 2 , that is 30% higher than that of the PTO-unused PZT capacitors. XRD analysis indicated that the use of the PTO seeding layer remarkably increased the relative intensity of (111) orientation. XRF studies showed that the atomic concentration ratio of Ti-to-Zr was increased by using PTO seeding layers. Necessarily, as the PZT thickness and crystallization temperature are lowered, the thickness of bottom electrode can be reduced as well. Finally, we successfully developed a capacitor stack height of below 400nm, which was comp...

Deep electron and hole traps were studied by admittance spectroscopy (AS) and deep level transient spectroscopy (DLTS) with electrical and optical (ODLTS) injection for GaN-based multi-quantum-well (MQW) light emitting diodes (LEDs) operating in the near-UV (385–390 nm), blue (445 nm), and green (515 nm) spectral regions. AS spectra were dominated by freezing out of Mg acceptors at temperatures around 150 K, by shallow centers in the MQW region, and, for green LEDs, by deeper electron traps with a level near Ec − 0.27 eV located in the MQW region. DLTS spectra showed electron traps with levels Ec − 0.8 eV (NUV), Ec − 0.5 eV (blue), Ec − 0.6 eV (blue and NUV), and Ec − 0.27(green LEDs). In ODLTS, hole traps near Ev + 0.75 eV (NUV), Ev + 0.65 eV (blue), and Ev + 0.45 eV (green LEDs) originating in the quantum well (QW) region were detected (the QW character was confirmed by using excitation light that generated electron-hole pairs only within the QWs). The levels of the electron and hole traps in LED struct...

In this paper, one step ferroelectric capacitor etching technology has been developed. Stacked capacitor layers with 0.75μm height were etched with a TiN hard mask. Etch selectivity increases as oxygen ratio in capacitor etching gases increases. After etching the electrodes and the PZT film, the slope of the stack capacitor was around 72 degrees and it has been proven that no si dew all fence was generated during the capacitor etching process and its leakage current was below 10–6A/cm2. The 0.9×0.9μm2 area capacitor for a 16M FRAM density has been well fabricated by one step etching process with very high selectivity to the mask.

We have deposited SiO2 using plasma-enhanced TEOS-based (PE-TEOS) CVD method and USG and PSG using atmosphere-pressure CVD method on Pb(Zr, Ti)O3(PZT) capacitors. The ferroelectric and dielectric properties of the SiO2 covered PZT capacitors were characterized. SIMS (secondary ion mass spectroscopy) was utilized to obtain hydrogen concentration in the deposited ILD and IMD materials. The concentration of hydrogen in the PE-TEOS-derived SiO2 was lower than that in the PSG and the USG. Internal stress was low tensile at room temperature and the behavior of thermal stress hysteresis was nearly similar for all SiO2 materials. Remnant polarization (Pr) of the PE-TEOS covered PZT capacitors was severely degraded as compared to that of as-deposited capacitors. From these results, we have concluded that the degradation of ferroelectric characteristics of PZT capacitors associated with the ILD and IMD processes was closely related to the plasma-induced damage.

The photometric modeling of LEDs as generalized Lambertian sources (GL-Sources) is discussed. Non-Lambertian LED sources, with axial symmetry, have important real-world applications in general lighting. In particular, so-called generalized Lambertian sources, following a cosine to the nth power distribution (n≥1), can be used to describe the luminous output profiles from solid-state lighting devices like LEDs. For such sources, the knowledge of total power (in Lumens [Lms]), the knowledge of the output angular characteristics, as well as source area, is sufficient information to determine all other critical photometric quantities such as: maximum radiant intensity (in Candelas [Cd = Lm/Sr]) and maximum luminance (in nits [nts = Cd/m2]), as well as illuminance (in lux [lx = Lm/m2]). In this paper, we analyze this approach to modeling LEDs in terms of its applicability to real sources.

We fabricated nanopillar light-emitting diodes (LEDs) embedded with Ag/SiO2 nanoparticles, and investigated the energy coupling processes between the localized surface plasmons of nanoparticles and the active quantum well regions of nanopillar LEDs. These nanoparticle-embedded nanopillar LEDs showed considerable increases in photoluminescence and electroluminescence intensities, compared with reference nanopillar LEDs. The observed optical enhancement was explained by the increased spontaneous emission rate caused by energy coupling from excitons in the InGaN/GaN quantum well active region of the LEDs to the localized surface plasmon modes of the Ag/SiO2 nanoparticles. A strongly enhanced characteristic photoluminescence decay also confirmed such an explanation.

Automatic target recognition (ATR) can be accomplished by many methods, including recognition of vibrometric signatures. In many cases, ATR is enhanced by photorefractive amplification, a two-wave mixing effect in which two input beams form a dynamic holographic grating. One of the two beams (the pump) diffracts from that grating into the other (the signal), assuming the characteristics of the signal. When the pump is much stronger than the signal, the diffracted pump becomes a highly amplified signal beam. Traditionally, however, the frequency at which this amplification can be applied is limited to 700 kHz in Cu:KNSBN, which has τ0 >100 ms (corresponding to a maximum amplification frequency of 1.6 Hz).

True 3D displays, whether generated by volume holography, merged stereopsis (requiring glasses), or autostereoscopic methods (stereopsis without the need for special glasses), are useful in a great number of applications, ranging from training through product visualization to computer gaming. Holography provides an excellent 3D image but cannot yet be produced in real time, merged stereopsis results in accommodation-convergence conflict (where distance cues generated by the 3D appearance of the image conflict with those obtained from the angular position of the eyes) and lacks parallax cues, and autostereoscopy produces a 3D image visible only from a small region of space. Physical Optics Corporation is developing the next step in real-time 3D displays, the automultiscopic system, which eliminates accommodation-convergence conflict, produces 3D imagery from any position around the display, and includes true image parallax. Theory of automultiscopic display systems is presented, together with results from our prototype display, which produces 3D video imagery with full parallax cues from any viewing direction.

Head-mounted or helmet-mounted displays (HMDs) have long proven invaluable for many military applications. Integrated with head position, orientation, and/or eye-tracking sensors, HMDs can be powerful tools for training. For such training applications as flight simulation, HMDs need to be lightweight and compact with good center-of-gravity characteristics, and must display realistic full-color imagery with eye-limited resolution and large field-of-view (FOV) so that the pilot sees a truly realistic out-the-window scene. Under bright illumination, the resolution of the eye is ~300 μr (1 arc-min), setting the minimum HMD resolution. There are several methods of achieving this resolution, including increasing the number of individual pixels on a CRT or LCD display, thereby increasing the size, weight, and complexity of the HMD; dithering the image to provide an apparent resolution increase at the cost of reduced frame rate; and tiling normal resolution subimages into a single, larger high-resolution image. Physical Optics Corporation (POC) is developing a 5120 × 4096 pixel HMD covering 1500 × 1200 mr with resolution of 300 μr by tiling 20 subimages, each of which has a resolution of 1024 × 1024 pixels, in a 5 × 4 array. We present theory and results of our preliminary development of this HMD, resulting in a 4k × 1k image tiled from 16 subimages, each with resolution 512 × 512, in an 8 × 2 array.

Microparticles including biological cells were trapped and manipulated using a continuous wave tweezer and a femtosecond laser tweezer. The difference of the optical trapping force between CW and femtosecond optical tweezers increased as the particle size decreased, possibly due to the self-focusing effect of the ultrashort pulses. Also, the white damage spots were generated near the focus during femtosecond optical trapping of biological cells even with extremely low average power. The instantaneous optical damage threshold was measured as a function of the trap depth as well. These results may help to optimize the optical trapping of biological cells using femtosecond lasers.

Using an acousto-optic beam deflector and a line scan camera, we constructed a non-mechanical, slit-scanning confocal microscope. It generates two-dimensional 512x512 images with speed of 60 frames/sec, which can be easily expanded, to 100 frames/sec. The measured axial and lateral resolutions of the system are 3.3 mm and

Summary form only given. Microspheres (2 /spl mu/m-diameter spheres) are trapped and manipulated using interferometric optical tweezers. The dielectric microspheres were aligned along the focused interference pattern generated by a Michelson interferometer and two-beam interference. Not only the shape of cell but the direction of budding and growth of the yeast cell can be changed by focused interference fringes. Although the yeast cell is trapped for several hours, it doesn't show any optical damage (we used near infrared lasers as trapping light source). Mechanical properties of budding yeast can be measured using the interferometric optical trap. Thus, interferometric optical tweezers enable one to trap and manipulate multiple yeast cells. We observed what influence the yeast cells in the optical potential well have on one another.

We present an implementation of fluorescence correlation spectroscopy with spectrally resolved detection based on a combined commercial confocal laser scanning/fluorescence correlation spectroscopy microscope. We have replaced the conventional detection scheme by a prism-based spectrometer and an electron-multiplying charge-coupled device camera used to record the photons. This allows us to read out more than 80,000 full spectra per second with a signal-to-noise ratio and a quantum efficiency high enough to allow single photon counting. We can identify up to four spectrally different quantum dots in vitro and demonstrate that spectrally resolved detection can be used to characterize photophysical properties of fluorophores by measuring the spectral dependence of quantum dot fluorescence emission intermittence. Moreover, we can confirm intracellular cross-correlation results as acquired with a conventional setup and show that spectral flexibility can help to optimize the choice of the detection windows.

Using a line scan camera and an acousto-optic deflector (AOD), we constructed a high-speed confocal laser line-scanning microscope that can generate confocal images (512 x 512 pixels) with up to 191 frames/s without any mechanically moving parts. The line scanner consists of an AOD and a cylindrical lens, which creates a line focus sweeping over the sample. The measured resolutions in z (depth), x (perpendicular to line focus), and y (direction of line focus) directions are 3.3 mum, 0.7 mum and 0.9 mum, respectively, with a 50x objective lens. This confocal microscope may be useful for analyzing fast phenomena during biological and chemical interactions and for fast 3D image reconstruction.