- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Development of a high temperature diamond anvil cell for x ray absorption experiments under extreme conditions
摘要： X-ray absorption spectroscopy (XAS) is presently a powerful and established tool to investigate solid and liquid matter at high pressure and high temperature (HP-HT). HP-HT XAS experiments rely on high pressure technology whose continuous development has extended the achievable range up to 100 GPa and more. In high pressure devices, high temperature conditions are typically obtained by using internal and external resistive heaters or by laser heating. We have recently developed a novel design for an internally heated diamond anvil cell (DAC) allowing XAS measurements under controlled high temperature conditions (tested up to about 1300 K). The sample in the new device can be rapidly heated or cooled (seconds or less) so the cell is suitable for studying melting/crystallization dynamics when coupled with a time-resolved XAS setup (second and sub-second ranges). Here we describe the internally heated DAC device which has been realized and tested in experiments on pure selenium at the energy dispersive ODE beamline of Synchrotron SOLEIL. We also present results obtained in XAS experiments of elemental Se using a large volume Paris-Edinburgh press, as an example of the relevance of structural studies of matter under extreme conditions.
关键词： high pressure,high temperature,DAC,Selenium,XAS
更新于2025-09-23 15:23:52
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Optical Pressure Sensor Based on the Emission and Excitation Band Width (FWHM) and Luminescence Shift of Ce3+ Doped Fluorapatite – High-Pressure Sensing
摘要： A novel, contactless optical sensor of pressure based on the luminescence red-shift and band width (full width at half maximum - FWHM) of the Ce3+-doped fluorapatite - Y6Ba4(SiO4)6F2 powder, has been successfully synthesized via a facile solid-state method. The obtained material exhibits a bright blue emission under UV light excitation. It was characterized using powder X-ray diffraction, scanning electron microscopy and luminescence spectroscopy, including high-pressure measurements of excitation and emission spectra, up to above ≈30 GPa. Compression of the material resulted in a significant red-shift of the allowed 4f→5d and 5d→4f transitions of Ce3+ in the excitation and emission spectra, respectively. The pressure-induced monotonic shift of the emission band, as well as changes in the excitation/emission band widths, have been correlated with pressure for sensing purposes. The material exhibits a high pressure sensitivity (dλ/dP ≈0.63 nm/GPa), and outstanding signal intensity at high-pressure conditions (≈90% of the initial intensity at around 20 GPa) with minimal pressure-induced quenching of luminescence.
关键词： Ce3+ doping,Contactless pressure gauge,Y6Ba4(SiO4)6F2 apatite phosphors,Lanthanide ions (Ln3+),Compression in DAC,Luminescent functional materials
更新于2025-09-23 15:23:52
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[IEEE 2018 Asia Communications and Photonics Conference (ACP) - Hangzhou, China (2018.10.26-2018.10.29)] 2018 Asia Communications and Photonics Conference (ACP) - Performance Improvement of IM-DD OFDM Systems by Nonuniform DAC Output Levels
摘要： We propose and experimentally demonstrate a nonuniform quantization scheme to improve the signal-to-quantification noise ratio (SQNR) for low-bit resolution digital-to-analog converter (DAC) based intensity-modulated direct-detection (IM-DD) orthogonal frequency division multiplexing (OFDM) transmission systems. In this scheme, the discrete output levels of DAC are nonuniform and properly assigned based on the A-law and Lloyd algorithm. The effectiveness of the proposed method is verified by IM-DD OFDM transmission systems with various modulation formats and resolution. The experimental results show maximal 3.9 dB performance improvement after 10-km standard single mode fiber (SSMF) transmission.
关键词： OFDM,IM-DD,Nonuniform quantization,DAC
更新于2025-09-23 15:22:29
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Raman high-pressure study of butane isomers up to 40 GPa
摘要： Raman spectroscopy studies on n and i-butane were performed at pressures of up to 40 GPa at ambient temperatures using the DAC technique. Normal butane undergoes two phase transitions at 1.9(5) GPa and 2.9(5) GPa and isobutane at 2.7(5) GPa and 3.5(5) GPa. These phase transitions were identi?ed based on observations of the splitting Raman modes and the appearance or disappearance of particular Raman peaks. Our results demonstrate the complex, high-pressure behavior of butane isomers.
关键词： Raman spectroscopy,high-pressure,DAC technique,phase transitions,butane isomers
更新于2025-09-23 15:21:01
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An Area-Efficient 10-Bit Buffer-Reused DAC for AMOLED Column Driver ICs
摘要： In this paper, we proposed an area-efficient 10-bit digital-to-analog converter (DAC) with buffer-reusing method to dramatically relief the severe area exploding issue in high-definition active-matrix organic light-emitting diode (AMOLED) driver integrated circuits (ICs). In our design, we implement the functionalities of a large number of switches and capacitors in conventional DAC by a compact internal buffer. Furthermore, we minimize the buffer capacity requirement by elaborately reusing the indispensable output buffer in the typical column driver. In this way, we can cut down nearly a half of the decoder-switches and simultaneously reduce the capacitor size from 8 C to 3 C without designing an intricate and power-consuming amplifier separately. A prototype 6-channel column driver employing the proposed buffer-reused DAC was fabricated by 0.35 μm 2P3M BCD (Bipolar, CMOS, DMOS) process and its effective layout area per channel is 0.0429 mm2, which is 42.8% smaller than that of the conventional 10-bit R-C DAC. Besides, the measured differential nonlinearity (DNL) and integral nonlinearity (INL) are 0.514 LSB/0.631 LSB, respectively and the maximum value of inter-channel deviation voltage output (DVO) is 3.25 mV. The settling time within 5.6 μs is readily achieved under 1.5 k?-resistance and 100 pF-capacitance load. Measurement results indicate that the proposed buffer-reused DAC can successfully minimize the die area while maintaining other required performances.
关键词： AMOLED displays,output buffer,column driver,digital-to-analog converter (DAC)
更新于2025-09-23 15:19:57
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Thermally-Induced Nonlinear Spatial Shaping of Infrared Femtosecond Pulses in Nematic Liquid Crystals
摘要： This paper presents a fully synthesizable phase-locked loop (PLL) based on injection locking, with an interpolative phase-coupled oscillator, a current output digital-to-analog converter (DAC), and a fine resolution digital varactor. All circuits that make up the PLL are designed and implemented using digital standard cells without any modification, and automatically Place-and-routed (P&R) by a digital design flow without any manual placement. Implemented in a 65 nm digital CMOS process, this work occupies only 110 μm × 60 μm layout area, which is the smallest PLL reported so far to the best knowledge of the authors. The measurement results show that this work achieves a 1.7 ps RMS jitter at 900 MHz output frequency while consuming 780 μW DC power.
关键词： standard cell,digital varactor,small area,low power,gated injection,injection-locking,dual loop,PLL,synthesizable,logic synthesis,edge injection,low jitter,PVT,AD-PLL,DAC,CMOS
更新于2025-09-19 17:13:59
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Design guidelines for edge-coupled waveguide unitravelling carrier photodiodes with improved bandwidth
摘要： This paper presents a fully synthesizable phase-locked loop (PLL) based on injection locking, with an interpolative phase-coupled oscillator, a current output digital-to-analog converter (DAC), and a fine resolution digital varactor. All circuits that make up the PLL are designed and implemented using digital standard cells without any modification, and automatically Place-and-routed (P&R) by a digital design flow without any manual placement. Implemented in a 65 nm digital CMOS process, this work occupies only 110 μm × 60 μm layout area, which is the smallest PLL reported so far to the best knowledge of the authors. The measurement results show that this work achieves a 1.7 ps RMS jitter at 900 MHz output frequency while consuming 780 μW DC power.
关键词： standard cell,digital varactor,small area,low power,gated injection,injection-locking,dual loop,PLL,synthesizable,logic synthesis,edge injection,low jitter,PVT,AD-PLL,DAC,CMOS
更新于2025-09-19 17:13:59
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Raman spectroscopy of poly (methyl methacrylate) under laser shock and static compression
摘要： Time-resolved Raman spectroscopy for visualizing molecular fingerprint snapshots at nanosecond time scale is a useful tool for detailed understanding of in situ shock behaviour of materials. This technique was applied to study the changes in molecular vibrations of poly (methyl methacrylate) (PMMA) under laser driven shock compression up to ~1.9 GPa in a confinement geometry. A layered target configuration is used to enhance the shock pressure. The vibrational modes are measured as a function of dynamic shock and static compression. The Grüneisen parameters and bond anharmonicities in PMMA are determined using compression behaviour of Raman modes. The deduced shock velocity (~3.5 ± 0.4 km/s) in PMMA based on the time evolution of shocked Raman mode at 1.9 GPa is in agreement with the one calculated (~3.7 km/s) from 1-D radiation hydrodynamic simulations. A comparative study on shock experiment and static high pressure Raman spectroscopic measurements is done. Static pressure measurement up to ~16 GPa show rapid blue shifting of C–H stretching modes.
关键词： Raman spectroscopy,PMMA,confinement geometry,Raman shift,laser shock,diamond anvil cell (DAC),static experiment
更新于2025-09-16 10:30:52
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[IEEE 2018 IEEE International Conference on Electro/Information Technology (EIT) - Rochester, MI (2018.5.3-2018.5.5)] 2018 IEEE International Conference on Electro/Information Technology (EIT) - DC Motor Cruise Control by Interfacing IR Sensor Tachometer and SIMULINK, Regardless Motor Specifications and Change of Shaft Load
摘要： DC motor could be controlled different ways with different approaches. One of the problems has been identifying internal specifications of DC motor such as Torque constant, back-emf constant, viscous friction constant, internal resistance and inductance. These parameters are needed for modelling the system of a DC motor. Unfortunately, those are not specified in most commercially manufactured DC motor’s data sheet. Most popular controlling methods available are PID controller, Adaptive controller or intelligent controller in some cases. Proposed experiment disregards all these problems and methods mentioned above to build a very simple, effective and cheap cruise controller of a DC motor. This experiment divided into two key parts; first phase focuses on a simple IR sensor tachometer designing in microcontroller (LPC1768 ARM) platform which performs DAC (digital to analog conversion) in essence. Tachometer’s RPM reading gives the feedback into controller function to compare against the desired RPM set by the user until they align on the same line. A SIMULINK diagram has been implemented in ARDUINO Mega for the cruise control which contains controller function. Results analyzed for different RPM and concludes the system’s high efficiency for RPM range between 300-1200.
关键词： RPM- revolution per minute,EMF- Electro motive force,DAC-Digital to analog converter,IRS- Infrared reflective sensor
更新于2025-09-10 09:29:36
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Calibrating a Voltmeter with a PJVS Using a DAC as a Real-Time Calibrated Transfer Standard
摘要： A Programmable Josephson Voltage Standard (PJVS) has been used to calibrate a voltmeter by measuring the difference between a Digital to Analog Converter (DAC) and a step-wise approximated sine wave from a PJVS with a difference amplifier (DA). The characterization of two different DAs was used to determine the accuracy in transferring the PJVS value to the voltmeter, operating the DAC as a real-time calibrated transfer standard with an uncertainty of a few μV/V.
关键词： PJVS,difference voltage,voltage measurement,ADC,DAC
更新于2025-09-10 09:29:36