Ultrafast Flame Annealing of TiO2 Paste for Fabricating Dye‐Sensitized and Perovskite Solar Cells with Enhanced Efficiency

Mesoporous TiO₂ nanoparticle (NP) films are broadly used as electrodes in photoelectrochemical cells, dye‐sensitized solar cells (DSSCs), and perovskite solar cells (PSCs). State‐of‐the‐art mesoporous TiO₂ NP films for these solar cells are fabricated by annealing TiO₂ paste‐coated fluorine‐doped tin oxide glass in a box furnace at 500 °C for ≈30 min. Here, the use of a nontraditional reactor, i.e., flame, is reported for the high throughput and ultrafast annealing of TiO₂ paste (≈1 min). This flame‐annealing method, compared to conventional furnace annealing, exhibits three distinct benefits. First, flame removes polymeric binders in the initial TiO₂ paste more completely because of its high temperature (≈1000 °C). Second, flame induces strong interconnections between TiO₂ nanoparticles without affecting the underlying transparent conducting oxide substrate. Third, the flame‐induced carbothermic reduction on the TiO₂ surface facilitates charge injection from the dye/perovskite to TiO₂. Consequently, when the flame‐annealed mesoporous TiO₂ film is used to fabricate DSSCs and PSCs, both exhibit enhanced charge transport and higher power conversion efficiencies than those fabricated using furnace‐annealed TiO₂ films. Finally, when the ultrafast flame‐annealing method is combined with a fast dye‐coating method to fabricate DSSC devices, its total fabrication time is reduced from over 3 h to ≈10 min.     

Design of a Novel Harmonic-Suppressed Microstrip Low-Pass Filter

A novel harmonic-suppressed microstrip low-pass filter (LPF) is proposed which is composed of defected ground structures and stepped-impedance shunt stubs as series L and shunt C components in the pass-band. Due to the attenuation poles of two kinds of resonators, it is found that harmonic responses are not only suppressed effectively, but the rejection in the stop-band is also deep and wide. Besides, the proposed LPF can be compactly implemented since both kinds of resonators have slow-wave characteristics     

Unsaturated polyester resins based on recycled PET: Preparation and curing behavior

The oligomers obtained from the glycolysis of Poly(ethlene terephthalate) (PET) waste were reacted with maleic anhydride to form a series of unsaturated polyester resins. The obtained resin was used to study the curing reaction with styrene by differential scanning calorimetry. The heats of reaction for styrene and polyester vinyl groups were measured by extrapolating the experimental results. Various kinetic parameters have been obtained using Kissinger expressions. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1052–1057, 2001     

Adaptive predistorter for power amplifier based on real-timeestimation of envelope transfer characteristics

A new adaptation technique for digital predistortion is presented. The proposed method employs the real-time input and output signals of a high power amplifier (HPA) to estimate the complex envelope transfer characteristics. Therefore, a look-up table update can be performed without Interrupting the normal transmission of messages through an HPA     

Synthesis and cost estimation of ethylene oxide process using PRO/Ⅱ

Ethylene oxide(EO)is a sold-out intermediate material for producing various chemicals.Major chemical companies are interested in whether new EO plant can create profit.This research is undertaken to investigate the economic feasibility of EO production.Direct oxidation of ethylene using silver on alpha-Al2O3 catalyst type is adapted to produce EO of 60 000t year.We conduct the conceptual design.Firstly,we synthesize the optimal structure and then determine optimal conditions and the size of the equipments.Feasibility study shows that profit and loss turning point turns out to be 3.2 years based on the present market price.In addition,we conducts the economic analysis to prepare the risk of raw material market price variation ranging from 70% to 130%.     

Enhancement of through-thickness thermal conductivity of sandwich construction using carbon foam

As a thermal management system, a sandwich construction was developed to have both superior thermal conductivity and structural integrity. The sandwich construction consists of a carbon foam core and unidirectional graphite/epoxy composite facesheets. An emphasis was put on enhancing the thermal conductivity of each phase of sandwich construction as well as interface between the phases. A commercially-available carbon foam was characterized mechanically and thermally. Property variation and anisotropy were observed with the highly conductive graphitic carbon foam. Co-curing of the composite facesheets with the carbon foam core was demonstrated to minimize the thickness of the adhesive layer between the facesheets and the core to produce the best construction of those tested. Comparison made with an adhesively bonded specimen shows that the co-curing is a more efficient method to enhance the through-thickness conductivity. Parametric studies with an analytic model indicate that degree of enhancement in the overall through-thickness conductivity of the sandwich construction from the enhancement of each component including the foam core, facesheet and the bonding methods.     

Application of a new efficient attitude determination algorithm on a ground simulator

In general, precise attitude information is required to control a ground simulator, which is designed to simulate attitude control of spacecraft. Two algorithms are well-known to determine the attitude through two or more observation vectors. One is the deterministic method, such as the TRI-axis Attitude Determination (TRIAD) algorithm, and the other is the optimal method, such as the QUaternion ESTimator (QUEST) algorithm. This paper suggests a new efficient attitude determination algorithm, which the authors name an algorithm “Averaging TRIAD.” First, it is transformed from the attitude matrix to the attitude angle vectors to maintain orthogonal constraints during calculation. Second, the covariance matrix is used instead of the variance and then it is applied to an unbiased minimum variance formula for more accurate solutions. Finally, the authors suggest a methodology to determine the attitude when more than three measurements are given. The performance of the Averaging TRIAD algorithm upon the combination of different sensors, which are fixed to the ground simulator, is investigated by numerical simulation in terms of standard deviations and computational time.     

Effect of filler on cure behavior of an epoxy system: Cure modeling

The effects of filler on the reaction of an epoxy system cured with aromatic diamine have been studied within the temperature range 70 ? 130°C using a differential scanning calorimeter. Various kinetic models including homogeneous reaction, diffusion-controlled reaction, surface reaction and nucleation and growth models have been tested. Kinetic analysis using integral and derivative procedures on the isothermal data indicates that the cure reaction process can be described well with the autocatalytical and surface reaction models. However, it has been found that the catalysis of fillers can be retarded effectively by the curing temperature.     

Dynamic signalling period allocation algorithm for wireless ATM MACprotocols

A control algorithm called DSPA (dynamic signalling period allocation) is presented which exploits information from mobile terminals for the dynamic allocation of signalling periods in wireless asynchronous transfer mode medium access control protocols. The algorithm increases allowable loads that guarantee quality of service, and maintains stable throughput even in the presence of variations in traffic