This study has examined the performance and temperature change characteristics of a satellite film heater fabricated using screen printing technology using silver paste. The temperature variations in the film heater attached to CFRP and Al 6061 substrates were modeled numerically in an FM (Flight Model) environment incorporating radiation heat transfers in a vacuum state under various sink temperatures. The results demonstrate that the constrained distance between heaters increases non-linearly with the sink temperature. The required power density to reach the maximum allowable temperature diminishes with the sink temperature. The required power density is higher than the ESCC standard of 0.54 W/cm², which is assessed in an EM (engineering model) environment without substrate.
This paper presents development and characterization of a disposable cell-based biochip for detection of hormone dependent responses of human nuclear receptors. The disposable cell-based biochip has chamber arrays for immobilize cell-based sensors and microfluidic channels for hormone and substrate injection. A prototype plastic microarray has been designed, fabricated, and validated for hormone dependent, cell-based, human nuclear receptor function. Depending upon the receptor employed, these sensors can determine predisposition to type II diabetes and cardiovascular diseases.
Fluorescent probes are widely used in biological research due to their sensitivity, selectivity, and versatility [1, 2]. Many fluorescence probes, such as fluorophores, typically have a variety of absorption and emission peaks ranging from UV to near-infrared. Therefore, a wide range of excitation wavelengths is required to simultaneously detect multiple fluorescent target analytes. Here, we propose a portable fluorometer with 13 different excitation LEDs (280 – 730 nm) that can be a viable option for simultaneously detecting multiple fluorophores. For fluorescence detection, a monochromator module was implemented to separates the color components of fluorescent emission and sequentially scan a range of wavelength (400 nm – 780 nm) with 1 nm resolution. For demonstration, fluorescein was selected as target analyte for this study. Fluorescein is an organic compound dye that is commonly used in many bioscience applications. For the excitation light source, different LEDs were used to offer a broad range of excitation wavelengths, ranging from 280 nm to 725 nm. Each LED was coupled with a color filter and a collimator lens to carry out a narrow excitation spectrum. LEDs were controlled by an LED driver IC and a microcontroller to provide a linear output current in the range of 0 to 300 mA. A multiplexer IC was implemented to sequentially turn on and off each excitation LED. The maximum absorbance and emission wavelength of fluorescein were 485 nm and 514 nm, respectively. For excitation, 434 nm LED was chosen instead of 470 nm to minimize spectral overlap between the excitation and emission spectra. The fluorescein was dissolved in methanol at a concentration of 220 mg/ml at room temperature (25 ºC). The figure shows the spectra of the excitation LED and fluorescein fluorescence measured with a developed portable fluorometer. The spectral profile of the excitation LED and the peak fluorescence of fluorescein was well-matched with previously measured value from the laboratory-based benchtop fluorometer (Fluorolog 3 FL3-22, Horiba, Japan). In summary, we have developed a portable fluorometer multiple LEDs covering a broad range of excitation wavelengths to simultaneously detect multiple fluorescent targets. Our compact fluorometer provides a viable option for multi-analyte detection in a variety of remote sensing applications such as point-of-care or environmental monitoring. Figure 1
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
This paper presents simulation and analysis of core switching noise for a CMOS ASIC test vehicle. The test vehicle consists of a ceramic ball grid array (CBGA) package on a printed circuit board (PCB). The entire test vehicle has been modeled by accounting for all the plane resonances using the cavity resonator method. The models included both the on-chip and off-chip decoupling capacitors. Using both time domain and frequency domain simulations, the role of plane resonances on power supply noise for fast current edge rates has been discussed. The models have been constructed to amplify certain parts of the test vehicle during simulations.
The purpose of this study was to confirm the possibility of using the ink stroke density and width as a non-destructive analysis factor for estimating the ink and ball size of a ballpoint pen in the field of identification of writing instruments for document evaluation. The density and width of strokes were measured by applying a constant pressure (100-300 g) to a total of 39 ballpoint pens of 4 types of ink (oil, low-viscosity oil, gel and water) and ball size (0.5-1.0 mm). As a morphological characteristic of stroke density, it was confirmed that there were four types: 1) Selective diffusion of high-viscosity ink, 2) Agglomeration, 3) Dot, 4) Selective diffusion of low-viscosity ink. The deposition value of ink stroke density showed a tendency to be measured twice as low for oil (33.74~47.26%) with high viscosity compared to gel (78.19~84.66%) and water (44.96~85.26%) with low viscosity of ink. The stroke width showed a tendency to increase as the pressure applied to the ballpoint pen and the size of the ball increased. The stroke width according to the ink was similar in the case of oily and low-viscosity oils, but in the case of neutral, it was about 100 μm higher than that of oil and low-viscosity oils. As a result, the density and width of strokes showed a difference in the characteristics that appeared according to the viscosity of the ink. In the order of non-destructive analysis for the identification of writing instruments, it is necessary to ① analyze the deposit shape and deposit value of ink stroke density, and ② to estimate the ink and ball size through ink width measurement. It was confirmed that it can be used.
Physical entities with inherent randomness have been investigated as anti-counterfeiting labels based on physical unclonable functions (PUFs). Herein, a transparent and flexible optical PUF label associated with multilevel complexity is demonstrated by taking advantage of the optical properties of hierarchical morphologies of the composite film composed of metal halide perovskite nanoparticles (MAPbBr3 NPs) and the intrinsic spinodal-decomposition-like phase separation of polymer blend (PMMA/PS blend). Due to the combinatorial effects of the photolysis synthesis of MAPbBr3 and the thermodynamic instability of the PMMA/PS blend, randomized patterns emerge at two-level scales. These patterns are intrinsically non-deterministic, and therefore, the PUF labels from the multilevel random patterns are challenging to replicate. This is mainly attributed to random spot patterns (higher-level patterns) confined within intricate bicontinuous patterns (lower-level patterns).
This abstract presents a solution-processed photovoltaic device based on the PbS (lead sulfide) colloidal quantum dots (CQDs). A simple fabrication method at room temperature makes the solution-processed photovoltaic devices be a suitable cost effective alternative. In addition to simplicity in the fabrication method, a key advantage of photovoltaic devices based on PbS colloidal quantum dots is the tunability of the absorption spectrum by controlling the size and shape of the PbS quantum dots [1]. The structure of the photovoltaic device is shown in the figure. Active area is composed of a superlattice of doped PbS quantum dots sandwiched between two electric contact layers. The active area makes a Schottky contact with an electrode having low work function such as aluminum on one side and an Ohmic contact with a transparent electrode such as ITO (Indium Tin Oxide) on the other side. Absorbed photons in the active layer generate neutral excitons in the PbS quantum dots, and subsequently charge dissociation takes places in the neutral region due to the internal electric field at the Schottky contact. Photogenerated electrons and holes flow toward the Al and ITO contacts, respectively. Fabrication process starts with the deposition of doped colloidal PbS quantum dots on an ITO coated glass substrate by a layer by layer (LBL) method in an inert condition at room temperature. The process is followed by aluminum deposition on top by physical vapor deposition. Fabricated photovoltaic device illustrates promising sensitivity to both entire visible and portion of infrared spectrum of sun light. Since both device structure and fabrication process are simple and process can be done in room temperature, fabrication on the flexible substrates is also feasible. References [1] C. de Mello Donega, "Synthesis and properties of colloidal heteronanocrystals," Chem. Soc. Rev., vol. 40, pp. 1512–1546, 2011. Figure 1
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