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Superatomic catalyst for efficient nitric oxide reduction using Al8O3 superatom-oxide framework

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Science China Chemistry 2025年

作者： Kaidong Shen Jiuqi Yi Chang Xu Qiquan Luo Xiaojun Wu Jinlong Yang Department of Chemistry Anhui University School of Chemistry and Materials Sciences University of Science and Technology of China Institutes of Physical Science and Information technology Anhui University key laboratory of precision and Intelligent Chemistry University of Science and Technology of China Innovation Center of Chemistry for Energy Materials (iChEM) University of Science and Technology of China

For cluster catalysts,reducing their size to single atoms gives rise to precise and high-selective catalytic performance,at the cost of losing some ***,the entirety with atom-like electronic shells and fine-tunable properties as clusters,are promising candidates for cluster ***,we predicted a superatom-assembled two-dimension Al8O3superatom-oxide framework （SOF） using first principles calculation,where the Al8core comprises two 8-electron Al4superatoms and further linked by oxygen atoms in a graphene-like lattice,resulting in porous and stable *** Al8O3-SOF serves as an efficient superatomic catalyst for nitric oxide （NO） reduction reaction,where the Al4superatomic unit acts cohesively as the active site throughout the catalytic process and its superatomic P orbital plays an important role in activating NO ***,the catalytic activity of Al8O3-SOF increases when the two central Al atoms of the Al8core are replaced by Ga atoms,reducing the limiting potential to-0.48 V comparable to that of the reported Pt（100）.Our work proposes a novel series of superatomic catalysts and reveals the superatomic behavior in the catalytic process,providing references for the development of efficient heterogeneous catalysts.

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Polarization Measurement Method Based on Liquid Crystal Variable Retarder(LCVR)for Atomic Thin-Film Thickness

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Nanomanufacturing and Metrology 2022年第2期5卷 159-166页

作者： Yucong Yuan Chengyuan Yao Wanfu Shen Xiaodong Hu Chunguang Hu state key laboratory of precision measuring technology and instruments Tianjin UniversityTianjin300072China

Atomic thickness thin films are critical functional materials and structures in atomic and close-to-atomic scale ***,fast,facile,and highly sensitive precision measurement of atomic film thickness remains *** reflected light has a dramatic phase change and extreme reflectivity considering the Brewster angle,indicating the high sensitivity of the optical signal to film thickness near this ***,the precision polarization measurement method focusing on Brewster angle is vital for the ultrahigh precision characterization of thin films.A precision polarization measurement method based on a liquid crystal variable retarder(LCVR)is proposed in this paper,and a measurement system with a high angular resolution is established.A comprehensive measurement system calibration scheme is also introduced to accommodate ultrahigh precision film thickness *** measurement accuracy to the subnanometer level is *** silicon oxide film samples of different thicknesses were measured around Brewster angle using the self-developed system and compared with a commercial ellipsometer to verify the measurement *** consistency of the thickness measurement results demonstrates the feasibility and robustness of the measurement method and calibration *** study also demonstrates the remarkable potential of the LCVR-based polarization method for atomic film thickness measurement in ultraprecision manufacturing.

关键词： Atomic thickness thin film Thickness Polarization measurement Brewster angle LCVR

Investigation of sorptive interactions between volatile organic compounds and supramolecules at dynamic oscillation using bulk acoustic wave resonator virtual sensor arrays

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Microsystems & Nanoengineering 2024年第4期10卷 175-184页

作者： Zilun Wang Zeyu Zhao Suhan Jin Feilong Bian Ye Chang Xuexin Duan Xiangdong Men Rui You state key laboratory of NBC Protection for Civilian Beijing 102205China state key laboratory of precision measuring technology&instruments Tianjin UniversityTianjin 300072China School of Instrument Science and Opto-Electronics Engineering Beijing Information Science and Technology UniversityBeijing 100192China

Supramolecules are considered as promising materials for volatile organic compounds(VOCs)sensing *** proper understanding of the sorption process taking place in host-guest interactions is critical in improving the pattern recognition of supramolecules-based sensing ***,we report a novel approach to investigate the dynamic host-guest recognition process by employing a bulk acoustic wave(BAW)resonator capable of producing multiple oscillation amplitudes and simultaneously recording multiple responses to ***-assembled monolayers(SAMs)ofβ-cyclodextrin(β-CD)were modified on four BAW sensors to demonstrate the gas-surface interactions regarding oscillation amplitude and SAM *** on the method,a virtual sensor array(VSA)type electronic nose(e-nose)can be realized by pattern recognition of multiple responses at different oscillation amplitudes of a single *** analysis was realized respectively by using principal component analysis(PCA)for individual VOC identification and linear discriminant analysis(LDA)for VOCs mixtures classification.

关键词： oscillation volatile dynamic

Self-Adaptive Grinding for Blind Tip Reconstruction of AFM Diamond Probe

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Nanotechnology and precision Engineering 2018年第2期1卷 150-155页

作者： Linyan Xu Qishan Guo Shuangbei Qian Sen Wu state key laboratory of precision measuring technology and instruments(Tianjin University) Tianjin 300072China

Blind tip reconstruction(BTR) method is one of the favorable methods to estimate the atomic force microscopy(AFM) probe shape. The exact shape of the characterizer is not required for BTR, while the geometry of the sample may affect the reconstruction significantly. A cone-shaped array sample was chosen as a characterizer to be evaluated. The target AFM probe to be reconstructed was a diamond triangular pyramid probe with two feature angles, namely front angle(FA) and back angle(BA). Four conical structures with different semi-angles were dilated by the pyramid probe. Simulation of scanning process demonstrates that it is easy to judge from the images of the isolated rotary structure, cone-shaped, the suitability of the sample to be a tip characterizer for a pyramid probe. The cone-shaped array sample was repeatedly scanned 50 times by the diamond probe using an AFM. The series of scanning images shrank gradually and more information of the probe was exhibited in the images, indicating that the characterizer has been more suitable for BTR. The feature angle FA of the characterizer increasingly reduces during the scanning process. A self-adaptive grinding between the probe and the characterizer contributes to BTR of the diamond pyramid probe.

关键词： AFM diamond probe BTR Cone characterizer Self-adaptive Grinding

External-cavity birefringence feedback effects of microchip Nd:YAG laser and its application in angle measurement

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Chinese Physics B 2009年第8期18卷 3438-3443页

作者：任成谈宜东张书练 state key laboratory of precision Measurement technology and instruments Department of Precision Instruments & MechanologyTsinghua University

External-cavity birefringence feedback effects of the microchip Nd：YAG laser are presented. When a birefringence element is placed in the external feedback cavity of the laser, two orthogonally polarized laser beams with a phase difference are output. The phase difference is twice as large as the phase retardation in the external cavity along the two orthogonal directions. The variable extra-cavity birefringence, caused by rotation of the external-cavity birefringenee element, results in tunable phase difference between the two orthogonally polarized beams. This means that the roll angle information has been translated to phase difference of two output laser beams. A theoretical analysis based on the Fabry-Perot cavity equivalent model and refractive index ellipsoid is presented, which is in good agreement with the experimental results. This phenomenon has potential applications for roll angle measurement.

关键词： microchip laser external-cavity birefringence feedback orthogonally polarized lasers angle measurement

Ultra-precision machining of cerium-lanthanum alloy with atmosphere control in an auxiliary device

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Nanotechnology and precision Engineering 2022年第3期5卷 30-35页

作者： Chenyu Zhao Shengjie Wu Min Lai state key laboratory of precision measuring technology and instruments Laboratory of Micro/Nano Manufacturing TechnologyTianjin UniversityTianjin 300072China

Cerium–lanthanum alloys are the main component of nickel–metal hydride batteries,and they are thus an important material in the greenenergy ***,these alloys have very strong chemical activity,and their surfaces are easily oxidized,leading to great difficulties in their *** improve the corrosion resistance of cerium–lanthanum alloys,it is necessary to obtain a nanoscale surface with low ***,these alloys can easily succumb to spontaneous combustion during ***,to inhibit the occurrence of fire,machining of this alloy in ambient air needs to be conducted at very low cutting speeds while spraying the workpiece with a large amount of cutting ***,this is inefficient,and only a very limited range of parameters can be optimized at low cutting speeds;this restricts the optimization of other cutting *** achieve ultraprecision machining of cerium–lanthanum alloys,in this work,an auxiliary machining device was developed,and its effectiveness was *** results show that the developed device can improve the cutting speed and obtain a machined surface with low *** device can also improve the machining efficiency and completely prevent the occurrence of spontaneous *** was found that the formation of a build-up of swarf on the cutting tool is eliminated with high-speed cutting,and the surface roughness(Sa)can reach 5.64 nm within the selected ***,the oxidation processes of the cerium–lanthanum alloy and its swarf were studied,and the process of the generation of oxidative products in the swarf was *** results revealed that most of the intermediate oxidative products in the swarf were Ce^(3+),there were major oxygen vacancies in the swarf,and the final oxidative product was Ce^(4+).

关键词： Cerium–lanthanum alloy Ultraprecision machining Surface roughness Atmosphere control

Uncertainty reevaluation in determining the volume of a silicon sphere by spherical harmonics in an Avogadro project

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Chinese Physics B 2011年第9期20卷 152-158页

作者：张继涛吴学健李岩 state key laboratory of precision Measurement technology & instruments Department of Precision Instruments and MechanologyTsinghua University

To determine the Avogadro constant with a target relative uncertainty of 2 x 10-s, the uncertainty component of the silicon sphere＇s volume introduced by the spherical harmonics method, which is usually used in determining the sphere＇s volume, is reevaluated. By means of representing the shape of the silicon sphere by an ellipsoid with Gaussian white noise in its diameters, the uncertainty of the current mapping methods based on the spherical harmonics theory can be estimated theoretically. It is evidenced that the uncertainty component attributed to the current mapping method is underestimated. To eliminate this effect as much as possible, the number of mapping points should be increased to more than before. Moreover, a new mapping method is proposed to accomplish the equal-area mapping with large number points on the silicon sphere.

关键词： metrology Avogadro constant silicon sphere spherical harmonics

Time-division multiplexing holographic display using angular-spectrum layer-oriented method(Invited Paper)

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Chinese Optics Letters 2016年第1期14卷 16-20页

作者：赵燕曹良才张浩谭巍吴圣函王崝杨强金国藩 state key laboratory of precision Measurement technology and instruments Department of Precision Instruments Tsinghua University

A time-division multiplexing method for computer-generated holograms （CGHs） is proposed to solve the problem of the limited space-bandwidth product. A three-dimensional （3-D） scene is divided into multiple layers at different depths. The CGH corresponding to each layer is calculated by an angular-spectrum algorithm that is effective at a wide range of propagation distances. All of the CGHs are combined into several group-CGHs. These group-CGHs are sequentially uploaded onto one spatial light modulator at a high frame rate. The spacebandwidth product can be benefited by the time-division processing of the CGHs. The proposed method provides a new approach to achieve high quality 3-D display with a fast and accurate CGH computation.

关键词： Bandwidth Holograms Holographic displays Light modulators Multiplexing Spectrum analysis Time division multiplexing

Low-repetition-rate, all-polarization-maintaining Yb-doped fiber laser mode-locked by a semiconductor saturable absorber

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Chinese Physics B 2017年第11期26卷 216-220页

作者：肖晓晟 state key laboratory of precision Measurement technology and instruments Department of Precision InstrumentsTsinghua University

A low-repetition-rate, all-polarization-maintaining（PM）-fiber sub-nanosecond oscillator is presented, which is simple and low-cost, composed of standard components. The ring cavity is elongated by 114-m-long standard PM fiber, and passively mode-locked by a fiber pigtailed semiconductor saturable absorber. Linearly polarized pulses with 1.66 MHz repetition rate and 22 dB polarization extinction ratio are generated at a wavelength of 1030 nm, which is determined by an intracavity filter. In addition, to demonstrate that the oscillator is a good seed for high energy pulse generation, an all-fiber master oscillator power amplifier is built and amplified pulses with energy about 2 μJ are obtained.

关键词： mode-locked fiber laser polarization maintaining master oscillator power amplifier