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Low-loss, dual-polarization asymmetric Mach-Zehnder interferometer chips for quantum key distribution

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Science China(Information Sciences) 2023年第8期66卷 45-51页

作者： Meizhen ren Lai ZHOU Zhiliang yuan Beijing Academy of Quantum Information Sciences

We have developed the first low-loss, dual-polarization, asymmetric Mach-Zehnder interferometer(AMZI) chip for phase-coding quantum key distribution(QKD) using silica planar lightwave circuit technology. The transmitter and receiver modules have a polarization extinction ratio greater than 20 and15 d B, respectively. Using a birefringent Mach-Zehnder interferometer, a polarization beam splitter is integrated into the receiver chip, while the polarization rotation function is obtained via a half-wave plate thin film. The receiver chip is entirely passive and has an excellent fiber C fiber loss of 1.90 d B, while the transmitter’s AMZI contains thermo-optical electrodes for adjusting the output pulses’ relative phase and intensity ratio. The chips are evaluated to have an interference visibility of greater than 98% across a broad temperature range, demonstrating their suitability for quantum key distribution applications.

关键词： quantum key distribution dual-polarization asymmetric Mach-Zehnder interferometer polarization beam splitter silica-based planar lightwave circuit technology

LOOK-AHEAD ALGORITHM FOR VELOCITY CONTROL BASED ON PARAMETERIZED CURVE INTERPOLATOR

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Chinese Journal of Mechanical Engineering 2008年第2期21卷 23-26页

作者： ren Kun fu Jianzhong CHEN Zichen College of Mechanical and Energy Engineering Zhejiang University Hangzhou 310027 China

To avoid suffering gouge and transient overshooting in high speed cutting machining, a novel parametefized curve interpolator model with velocity look-ahead algorithm is proposed. Based on a prearrangement step interpolation algorithm for parameterized curves and considering high curvature points, parameterized curve tool path is divided into acceleration segments and deceleration segments by look-ahead algorithm. Under condition of characteristics of acceleration and deceleration stored in control system, deceleration before high curvature points and acceleration after high curvature points are realized in real-time in high speed cutting machining. Based on new parameterized curve interpolator model with velocity look-ahead algorithm, a real cubic spline is machined simulativly. The simulation results show that velocity look-ahead algorithm improves velocity changing more smoothly.

关键词： High speed cutting machining Parameterized curve interpolator Look-ahead algorithm

Recent Advances of Bismuth Oxychloride Photocatalytic Material: Property, Preparation, and Performance Enhancement

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Journal of Electronic Science and Technology 2020年第2期18卷 119-137页

作者： Wen-Wen Liu ren-fu Peng College of Physical Science and Engineering Yichun UniversityYichun 336000

Due to its unique layered structure, bismuth oxychloride(BiOCl) has potential applications as a photocatalytic material in clean energy utilization and environmental purification. In recent years, researchers have carried out a lot of studies and made important progress for the preparation and performance enhancement of *** this review, the charge separation property of BiOCl was analyzed based on the crystal structure and electronic structure. Subsequently, the common preparation method of BiOCl was expounded, and the growth mechanism of BiOCl was introduced. furthermore, the strategies for modulating the photocatalytic performance of BiOCl via doping, vacancy creation, internal electric field tuning, co-catalysts modification, composites construction, and using sensitizers were summarized. Finally, in view of the current research status of the BiOCl photocatalytic material, some problems still need to be addressed including exploring the method of controlled synthesis of BiOCl exposed other high energy surfaces, developing advanced characterization methods to clarify the detailed transfer path of the photogenerated charge, and expanding the photocatalytic application range of BiOCl.

关键词： structure. summarized vacancy

Effects of Hot Bending Parameters on Microstructure and Mechanical Properties of Weld Metal for X80 Hot Bends

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Journal of Iron and Steel Research International 2014年第12期21卷 1129-1135页

作者： Xu WANG Bo LIAO Da-yong WU Xiu-lin HAN yuan-sheng ZHANG fu-ren XIAO Key Laboratory of Metastable Materials Science and Technology College of Materials Science and EngineeringYanshan University CNPC Bohai Petroleum Equipment Manufacture Co. Ltd. China Petroleum Technology and Development Corporation

Mechanical properties of weld metal are the key factors affecting the quality of heavy-wall X80 hot induction bends. The effects of bending parameters on the mechanical properties of weld metal for hot bends were investigated by simulation conducted on a Gleeble 3500 thermal simulator. Continuous cooling transformation （CCT） dia- grams of the weld metal were also constructed. The influences of hot bending parameters （such as reheating temperature, cooling rate, and tempering temperature） on the microstructure and mechanical properties of weld metal were also analyzed. Results show that the strength of all weld metal specimens is higher than the value indicated in the technical specification and increases with the increase of reheating temperature, cooling rate, and tempering tempera ture. The impact toughness is apparently related to the variation of reheating temperature, cooling rate, and tempering temperature.

关键词： hot induction bend X80 steel weld metal heat treatment microstructure

Drag increment induced by a small-scale forward-facing step in Mach number5 turbulent boundary layer flows

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Chinese Journal of Aeronautics 2020年第10期33卷 2491-2498页

作者： Yifei XUE Jie ren Jinling LUO Song fu School of Aerospace Engineering Tsinghua UniversityBeijing 100084China Department of Mechanical Engineering University of NottinghamNottingham NG72RDUnited Kingdom Beijing Aerospace Technology Institute Beijing 100074China

Small-scale roughness elements or imperfections are inevitable over the surface of a flight *** aerodynamics of these small-scale structures is difficult to predict but may play an important role in the design of a flight vehicle at high *** forward-facing step is a typical type of roughness *** experiments have been conducted to study the aerodynamics of supersonic forward-facing step,especially with a step height larger than boundary layer ***,few studies focus on small *** improve the understanding of small-scale forwardfacing step flow,we perform a series of simulations to analyze its aerodynamic influence on a Mach number 5 turbulent boundary *** general flow structures are analyzed and *** shock waves can be induced by the step even if the step height is much smaller than the boundary layer *** significant shocks are the separation shock and the reattachment *** influenced area by the step is *** the increase of the step height,the non-dimensional influence area decreases and gradually converges when the step height reaches the boundary layer *** are two normalized distributions of the skin friction coefficient and pressure coefficient associated with step *** using the normalized parameters,a power-law relationship between the step height and the drag increment coefficient is revealed and fits the simulation results *** is further illustrated that this relationship still holds when changing the inlet angle of attack,but needs slight modification with the angle of attack.

关键词： Aerodynamics Drag increment Forward-facing step Hypersonic flow Turbulent boundary layer

Shape-dependent hydrogen generation performance of Pt Pd bimetallic co-catalyst coupled with C_(3)N_(4)photocatalyst

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Rare Metals 2021年第12期40卷 3554-3560页

作者： Wen-Wen Liu Jun Pan ren-fu Peng College of Physical Science and Engineering Yichun UniversityYichun 336000China State Key Laboratory for Powder Metallurgy Central South UniversityChangsha 410083China

The shape-dependent performance of metal cocatalysts in photocatalysis has been one of the research focal points in recent *** this study,Pt Pd/C_(3)N_(4)hybrid structures were constructed to reveal the effect of the shape of the Pt Pd bimetallic co-catalyst on the performance of photocatalytic hydrogen *** Pd nanocubes(NCs)and nanotetrahedrons(NTs)were sequentially deposited in situ on the surface of C_(3)N_(4)nanosheets,establishing a strong contact interface to ensure the smooth transfer of photoinduced ***-visible(UV-Vis)diffuse reflectance spectroscopy and photoelectrochemical experiments revealed that the Pt Pd NCs/C_(3)N_(4)photocatalyst had comparable light absorption ability and equivalent carrier separation and transfer efficiency in comparison with the Pt Pd NTs/C_(3)N_(4)photocatalyst,which excluded the influence of these factors on shape-dependent *** photocatalytic hydrogen generation results indicate that the hydrogen generation rate of the Pt Pd NCs/C_(3)N_(4)photocatalyst is 1.33 times higher than that of the Pt Pd NTs/C_(3)N_(4)photocatalyst,demonstrating that the cubic Pt Pd bimetallic co-catalyst is more conducive to hydrogen generation compared to the tetrahedral Pt Pd bimetallic co-catalyst.

关键词： PtPd bimetallic co-catalyst C_(3)N_(4) Shape Hydrogen generation Photocatalyst

Change of Geographic Information Service Model in Mobile Context

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Geo-Spatial Information Science 2005年第4期8卷 269-275页

作者： ren fu DU Qingyun Key Laboratory of Geographic Information System Ministry of Education School of Resource and Environment Science Wuhan University 129 Luoyu Road Wuhan 430079 China 不详

A research on that how the topic of mobility, which is completely different but tightly relevant to space, provides new approaches and methods so as to promote the further development of geographic information services, will accumulate basic experience for different types of relative information systems in the wide fields of location based services. This paper analyzes the meaning of mobility and the change for geographic information service model, it describes the differences and correlation between M GIS and traditional GIS. It sets a technical framework of geographic information services according to mobile context and provides a case study.

关键词： geographic information services mobile GIS mobile computing LBS, mobility GIS

Improvement on the manipulation of a single nitrogen-vacancy spin and microwave photon at single-quantum level

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Communications in Theoretical Physics 2021年第6期73卷 43-50页

作者： yuan Zhou Dong-Yan Lü Guang-Hui Wang Yan-Hua fu Ming-Yao He Hong-Tao ren School of Science Hubei University of Automotive TechnologyShiyan 442002China Department of of Automobile Engineering Hubei University of Automotive TechnologyShiyan 442002China School of Materials Science and Engineering Liaocheng UniversityLiaocheng 252000China

It remains a great challenge to realize direct manipulation of a nitrogen-vacancy(NV)spin at the single-quantum level with a microwave(MW)*** an alternative,a hybrid system with the spin–phonon–photon triple interactions mediated by a squeezed cantilever-type harmonic resonator is *** to the general mechanical parametric amplification of this in-between phonon mode,the direct spin–phonon and photon–phonon couplings are both exponentially enhanced,which can even further improve the coherent manipulation of a single NV spin and MW photon with a higher *** view of this triple system with enhanced couplings and the additional sideband adjustable designs,this scheme may provide a more efficient phonon-mediated platform to bridge or manipulate the MW quantum and a single electron spin *** is also hoped to evoke wider applications in the areas of quantum state transfer and preparation,ultrasensitive detection and quantum nondestructive measurement,etc.

关键词： NV center mechanical parametric amplification quantum manipulation

Detached-eddy simulation of supersonic flow past a spike-tipped blunt nose

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Chinese Journal of Aeronautics 2018年第9期31卷 1815-1821页

作者： yuan XUE Liang WANG Song fu School of Aerospace Engineering Tsinghua University

Space vehicle in atmosphere travels mostly at supersonic speed and generates a very strong bow shockwave around its blunt nose. Oblique shock and conical separated flow zone generated by a forward disk-tip spike significantly reduce the drag by reducing the high pressure area on the blunt nose. This study employs improved delayed detached eddy simulation to investigate the characteristic flow structures around a spike-tipped blunt nose at Mach number of 3 and Reynolds number（based on the blunt-body diameter） of 2.72x10;. The calculated time-averaged quantities agree well with experimental data. Characteristic frequencies in different flow regions are extracted using fast Fourier transform. It is found that two distinct instability modes exist: oscillation mode and pulsation mode. The former is related to the foreshock/turbulence interaction with nondimensional frequency at around 0.004. The latter corresponds to the interaction between turbulence and shock structures around the blunt nose, with a typical coherent structure shedding frequency at 0.092.

关键词： Detached-eddy simulation Drag reduction Oscillation mode Pulsation mode Spike-tipped blunt vehicle Supersonic flow