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A facile route for synthesis of highly pure α-CaB4O7 compound
摘要： In this study, a facile route was developed for the synthesis of α-CaB4O7 compound. Ammonium tetraborate tetrahydrate (ATB) was used as the source of Boron. The compound was obtained using high-temperature solid-state reaction technique (840°C) and heat treatment process was introduced to enhance the phase purity and crystallinity. To control the formation of calcium tetraborate single phase, an excess amount of B2O3 (2wt%) was added to the starting powder mixture. Various analytical methods such as X-ray diffraction (XRD), Raman and Fourier transform infrared (FTIR) spectroscopies, Field emission scanning electron microscopy (FE-SEM), and X-ray photoelectron spectroscopy (XPS) were employed to characterize the prepared sample. Phase purity and crystallinity were evaluated by X-ray diffraction analytic method. Raman and FTIR spectroscopies were performed to confirm the atomic bond formation and its borate anionic group. FE-SEM was carried out for the morphological study of α-CaB4O7 compound and Energy dispersive X-ray (EDX) analysis was used to investigate the elemental composition of the prepared sample. XRD analysis confirmed that the prepared sample has alpha phase structure with monoclinic symmetry. The peaks correspond to unwanted phases (CaB2O4, Ca2B6O11) were not observed in the X-ray diffraction pattern of the prepared CaB4O7 compound. XPS was performed and its spectrum showed all expected characterization peaks for the first time, which is in agreement with FE-SEM and EDX results.
关键词： CaB4O7 compound,solid-state reaction,phase purity,highly crystalline
更新于2025-09-23 15:21:21
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Excited-state intramolecular proton transfer-based multifunctional solid-state emitter: a fluorescent platform with ‘write-erase-write’ function
摘要： The excited-state intramolecular proton transfer (ESIPT)-based molecular probes have drawn significant attention owing to their environment-sensitive fluorescence properties, large Stokes shift and emerged as building blocks for the development of molecular sensors and switches. However, most of the ESIPT-based fluorophores exhibit weak emission in the solid state limiting the scope of real-time applications. Addressing such issues, herein, we presented a C3-symmetric like molecular architecture employing a simple one-step Schiff base condensation between triaminoguanidinium chloride and 3,5-di-tert-butyl-2-hydroxybenzaldehyde (TGHB). The temperature-dependent fluorescence studies including at 77 K indicated the strong emission from the keto tautomer compared to that of the enol. The facile ESIPT in TGHB in the solid-state led to a remarkable enhancement of fluorescence quantum yield of 1600-times compared to that of the solution (λem = 545 nm) by restricting the intramolecular rotation and subsequently suppressing the nonradiative deactivation. The excited–state processes were further elucidated through time-resolved fluorescence measurements. TGHB exhibited turn on-off fluorescence upon exposure to acid /base vapor in the form of powder as well as transparent, free-standing thin film. A rewritable and erasable fluorescent platform was demonstrated using TGHB as molecular ink, which offers a potential testbed for performing multiple times ‘write-erase-write’ cycles. In addition, TGHB, possessing multiple binding sites (O and N donors) involving the central core of triaminoguanidinium cation, displayed selective turn-on fluorescence with Zn2+. The structure-property relationship revealed in the present study provides insight towards the development of novel cost-effective multifunctional materials promising for stimuli-responsive molecular switches.
关键词： molecular ink,thin film,ESIPT,multifunctional,solid-state emission,fluorescence switching
更新于2025-09-23 15:21:21
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An evaluation of computed tomography dose index measurements using a pencil ionization chamber and small detectors
摘要： The aim of this study was to compare the values of the computed tomography dose index 100 (CTDI100) obtained using two small detectors (i.e. a small ionization chamber and a small solid state detector) with those obtained from a 100-mm pencil ionization chamber for various input CT parameters: beam width, kVp, mAs, pitch, and head-body phantom variation. The measurement of CTDI100 using the 100-mm pencil chamber was carried out in a single rotation of axial mode, while the measurement using small detectors was carried out in helical mode. The differences of CTDI100 values obtained with two small detectors were about 7% for all variations. The differences of CTDI100 values obtained with small detectors and a 100-mm pencil ionization chamber for beam widths of more than 4 mm were within 40%. However, for the narrowest beam widths (4 mm), the difference between them was very large (about 150%).
关键词： computed tomography dose index (CTDI),CT dose profiler,small solid state detector,CT dosimetry,small detector,small ionization chamber
更新于2025-09-23 15:21:21
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Electron sources based on diamond pin-diodes
摘要： Efficient electron sources are of ongoing interest in particular for space and terrestrial power telecommunications and radar applications. With conventional cathode technology based on thermionic- and field electron emission a novel approach for direct electron emission is realized through a diamond pin diode. Electrons injected into the conduction band of the intrinsic layer of the diode can be released into vacuum with a negative electron affinity surface of the i-layer. The diamond pin diodes were prepared on boron doped (p-type) substrates with (111) surface orientation. A high purity intrinsic and a phosphorus doped diamond layer (n-type, ~400nm thickness) were deposited in dedicated PECVD systems, respectively. An additional contact layer comprised of nanostructured carbon was grown in a dedicated PECVD. The layered device was processed by lithography utilizing an aluminum hard mask to etch mesa structures with diameters ranging from 50μm to 200μm. The final devices were treated in a pure hydrogen plasma to induce the negative electron affinity properties of the i-layer. After an annealing step in high vacuum individual pin diodes were biased in forward current and voltages up to 20V. The observation of light from the diode was attributed to the UV exciton state and indicated bipolar transport. At a diode current of about 80mA an electron emission current of 25μA was observed from a single 200μm diameter diode.
关键词： Diamond,solid state electronics,doping,phosphorus,electron emission,plasma-enhanced chemical vapor deposition,nanostructured carbon,pin diode,single crystal
更新于2025-09-23 15:21:21
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[Springer Theses] Electrical Properties of Indium Arsenide Nanowires and Their Field-Effect Transistors || Introduction
摘要： As the miniaturization and integration of solid-state electronic devices has continued to increase rapidly with the demands of high speed, low power consumption and high storage density, the conventional Si-based technology has lost their advantages on fabrication process. Therefore the technologies based on new materials gradually attract researchers’ attention. Among them, Indium Arsenide (InAs) nanowires (NWs) with high electron mobility is one of the most promising candidate. In this chapter, we introduce the advantages of InAs nanowire on electronic devices and the development status of InAs nanowire electronic devices. Also, the topic ideas and chapter arrangements of this thesis are presented.
关键词： solid-state,high electron mobility,electronic devices,InAs nanowires,miniaturization
更新于2025-09-23 15:21:21
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Identification of spherical and non-spherical protein by solid-state nanopore
摘要： Three-dimensional structure of a protein plays an important role in protein dynamics in biological system of human. By now, it remains challenge to characterize and quantify the shape of a protein at single-molecule level. Nanopore, as a novel single-molecule sensor, has been widely applied in many fields such as DNA sequencing and human diseases diagnosis. In this paper, we investigated the translocation of sphere-like con.A and the prolate Bovine Serum Albumin (BSA) under electric field by solid-state nanopore. By analyzing the ionic current, the con.A and the BSA could be characterized and differentiated due to their intrinsic shape difference. Because the prolate BSA will have the preferred orientations for higher electric field when it is residing inside the nanopore, thus multiple ionic current blockade levels will be observed. While for the spherical con.A, there is only one ionic current blockade level. This method presented here will be potentially applied to fingerprint a single protein as a new method having features of low-cost and high-throughput in the near future.
关键词： orientation,solid-state nanopore,shape,electric field,ionic current,protein
更新于2025-09-23 15:21:21
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[IEEE 2019 7th International Renewable and Sustainable Energy Conference (IRSEC) - Agadir, Morocco (2019.11.27-2019.11.30)] 2019 7th International Renewable and Sustainable Energy Conference (IRSEC) - Elaboration and Characterization of (Ce,Sm) Doped Lanthanum Oxychloride for Photovoltaic Solar Cell
摘要： The spectral incoherence due to the emission of sunlight and the absorption of silicon solar cells cause large solar energy losses, leading to a low photovoltaic efficiency. So that low energy photons cannot be used efficiently, while the majority of high energy photons are dissipate. Doped rare earth ions (RE) are expected to solve this problem, thanks to their spectral modification characteristics and luminescence properties. In this work we present the synthesis of LaOCl co-doped by trivalent rare earth with the couple of Ce3+/Sm3+ employed in photovoltaic cell down conversion. LaOCl: Ce3+/Sm3+ phosphors were prepared by the solid-state method, and their structures properties were investigated by using X-ray diffraction, Infrared Spectroscopy and MEB analysis. The study shows that tetragonal LaOCl: Ce3+/Sm3+ can be synthesized by the solid-state reaction at 700 °C for 4 h.
关键词： Down conversion,Lanthanum oxychloride,Solid-state,Photovoltaic,Rare Earth
更新于2025-09-23 15:21:01
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Tangentially and radially polarized Nd:YAG hollow lasers with two pairs of axicons
摘要： We present a novel method for generating tangentially and radially polarized laser radiations by using two pairs of positive and negative axicons. Tangentially and radially polarized diode-pumped Nd:YAG hollow lasers were demonstrated respectively. At an incident pump power of 17.8 W, the output power of tangentially and radially polarized laser beam is 6.9 W and 8.6 W, respectively. Polarization purity of tangentially and radially polarized laser beam is 99.2% and 98.7%, respectively. The experimental results reveal that tangentially and radially polarized laser beams with high polarization purity can be generated by resonator cavity consisting of only axicons. To the best of our knowledge, this is the first time that the cylindrical vector laser beam was realized only by axicons.
关键词： Solid-state laser,Radially polarized,Tangentially polarized,Axicons
更新于2025-09-23 15:21:01
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SBS pulse compression using bulk fused silica by diode-pumped solid-state lasers at 1??kHz repetition rate
摘要： This study is focused on constructing a highly stable diode-pumped solid-state laser system by conducting experiments on high-repetition-rate SBS pulse compression using bulk fused silica. A multi-rod serial-connection structure is adopted for SBS expriments by comparing K8 glass and fused silica medium at a 10 Hz repetition rate. The optimized structure is obtained according to variation of the pump power density. Based on the optimized structure, fused silica-based SBS pulse compression is carried out in the range of 100–1000 Hz and the parameter performance of laser system after compression is also evaluated by comparing a HT270 liquid medium. Experimental results indicate that the energy e?ciency of fused silica-based SBS is improved by approximately 40% compared with that of K8 glass. Further, the energy relative standard deviation of fused silica-based SBS is reduced by approximately 88% compared with HT270 medium, indicating that bulk fused silica is advantageous for high-repetition-rate SBS pulse compression because of its un-?uidity, high thermal conductivity and power-load ability. In addition, a 1 kHz highly-stable sub-nanosecond compressed pulse is achieved using bulk fused silica medium at a pump energy of 50 mJ. Furthermore, the SBS energy e?ciency can be further improved by increasing the input energy.
关键词： Pulse compression,High repetition rate,Solid-state lasers,Sub-nanosecond pulse,Stimulated Brillouin scattering (SBS)
更新于2025-09-23 15:21:01
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A broadband ultraviolet light source using GaN quantum dots formed on hexagonal truncated pyramid structures
摘要： Broadband ultraviolet (UV) emission has been achieved from the GaN quantum dots grown on different facets of hexagonal truncated pyramidal structures. The GaN-based structures include both semipolar and polar facets, on which the intrinsic piezoelectric fields and the growth rates are different. In addition, a strain is locally suppressed at the boundaries of the truncated pyramid structure. As a result, the emission wavelength of quantum dots on various facets and boundaries becomes quite different, rendering a solid-state broadband UV light source with homogenerous intensity in a wide wavelength range.
关键词： broadband ultraviolet emission,GaN quantum dots,solid-state broadband UV light source,hexagonal truncated pyramid structures
更新于2025-09-23 15:21:01