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Optimal transport of cold atoms by modulating the velocity of traps

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Chinese Physics B 2013年第2期22卷 232-238页

作者：韩景珊许忻平张海潮王育竹 Key Laboratory for Quantum Optics Center for Cold Atom PhysicsShanghai Institute of Optics and Fine MechanicsChinese Academy of Sciences

This work experimentally demonstrates a new method of optimizing the transport of cold atoms via modulating the velocity profile imposed on a magnetic quadrupole *** trap velocity and corresponding modulation are controlled by varying the currents of two pairs of anti-Helmholtz *** 87Rb atoms are transported in a non-adiabatic regime over 22 mm in 200 *** the transported atoms their final-vibration amplitude dependences of modulation period number,depth,and initial phase are *** modulation period n = 5,modulation depth K = 0.55,and initial phase φ = 0,cold atom clouds with more atom numbers,smaller final-vibration amplitude,and lower temperature are efficiently *** analysis and numerical simulation are also provided,which are in good agreement with experimental results.

关键词： transport of cold atoms modulation velocity profile

A Structure-activity Relationship (SAR) Study of Fluoroquinolones with Biological Activity against ***

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Chinese Journal of Structural Chemistry 2006年第1期25卷 33-40页

作者：李小红张瑞州程新路杨向东 institute of atom and Molecular Physics Sichuan University Chengdu 610065 China Xinxiang Teacher’s College Xinxiang 453000 China

Structure-activity relationship techniques were employed to classify fluoroquinolones against ***. Density functional theory （DFT） was used to calculate a set of molecular descriptors （properties） for eighteen fluoroquinolones. The descriptors were further analyzed using the principal component analysis （PCA）, hierarchical cluster analysis （HCA） and K-nearest neighbor （KNN） chemometeric method. The PCA and HCA methods are quite efficient to classify the eighteen compounds into two groups （active and inactive） according to their degrees of anti- *** activity. The classified result is consistent with the clinic experimental result. The PCA shows that the variables Q3 （net charge on atom 3）, QA （net charge on ring A）, QB （net charge on ring B）, VOL （molecular volume） and A （surface area） are found to be responsible for the separation between compounds with higher and lower ***.

关键词： structure-activity relationship DFT PCA HCA KNN

MAGNETIC MOMENT AND CURIE TEMPERATURE OF AMORPHOUS (Fe_(100-x)B_(x))_(88)Nd_(12±ε) ALLOYS

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Chinese Physics Letters 1990年第2期7卷 89-92页

作者： SHEN Baogen ZHAO Jiangao ZHANG Zhiying GU Benxi DING Jun HHomburg S.Methfessel institute of Physics Academia SinicaBeijing 100080 Department of Physics Nanjing UniversityNanjing 210008 institute fur Experimentalphysik Ⅳ Ruhr-UniversitatBochumFRG

The magnetization curves at 1.5K and Curie temperature of amorphow (Fe_(100-x)B_(x))_(88)Nd_(12±ε) alloys were *** spontaneous magnetizations is explained by a noncollinear *** average magnetic moment μ_(Fe) per Fe atom decreases monotonically with increasing x,and becomes more rapid when x>*** B content dependence of Curie temperature shows a mazimum at x=*** xatoms.

关键词： structure. alloys magnetization

Automatic compensation of magnetic field for a rubidium space cold atom clock

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Chinese Physics B 2016年第7期25卷 192-195页

作者：李琳吉经纬任伟赵鑫彭向凯项静峰吕德胜刘亮 Key Laboratory for Quantum Optics and Center of Cold atom Physics Shanghai Institute of Optics and Fine MechanicsChinese Academy of Sciences

When the cold atom clock operates in microgravity around the near-earth orbit, its performance will be affected by the fluctuation of magnetic field. A strategy is proposed to suppress the fluctuation of magnetic field by additional coils, whose current is changed accordingly to compensate the magnetic fluctuation by the linear and incremental compensation. The flight model of the cold atom clock is tested in a simulated orbital magnetic environment and the magnetic field fluctuation in the Ramsey cavity is reduced from 17 nT to 2 nT, which implied the uncertainty due to the second order Zeeman shift is reduced to be less than 2×10^（-16）. In addition, utilizing the compensation, the magnetic field in the trapping zone can be suppressed from 7.5 μT to less than 0.3 μT to meet the magnetic field requirement of polarization gradients cooling of atoms.

关键词： laser cooling space cold atom clock magnetic field compensation

Stable copper boron–imidazolate cage as Cu-riched enzyme for highly efficient electrocatalytic CO2 reduction to ethylene

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Science China Chemistry 2025年

作者： Jun-Qiang Chen Qiao-Hong Li Qin-Long Hong Ping Shao Hai-Xia Zhang Jian Zhang State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences

Single-atom catalyst has garnered widespread attention to mimic mature enzymes due to its well-defined atomic structure and coordination environments. However, since the carbon–carbon（C–C） coupling reactions require synergistic catalysis of multiple sites, single-atom catalysts suffer from insufficient active sites and unclear reaction mechanisms. Controlling the reaction intermediates in a precisely targeted pocket through careful metal–organic cage design is therefore crucial. Here, we prepare a tetrahedral [Cu6L4]-type boron–imidazolate cage integrating highly active Cu sites and optimized cavity, which exhibits enzyme like specific catalytic performance in electrochemical CO2reduction reaction（CO2RR） to enhance the selectivity of *** analyses and computational calculations suggest that the single Cu site together with neighboring boron–imidazolate ligands provides suitably synergistic effects that enable the energetically favorable formation of an *COCHO intermediate, a key step determining selectivity. As a result, the [Cu6L4]-type cage of BIC-145 achieves a Faradaic efficiency of 28% for C2H4maintaining an average current density of -3.54 mA cm-2over a 5-hour electrolysis period. This work represents the first example for studying single-metal site catalysts with ultra-low coordination numbers through the rational design of metal–organic cages.

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Initial Tests of a Rubidium Space Cold atom Clock

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Chinese Physics Letters 2016年第6期33卷 17-20页

作者：李琳屈求智汪斌李唐赵剑波吉经纬任伟赵鑫叶美凤姚媛媛吕德胜刘亮 Key Laboratory of Quantum Optics and Center of Cold atom Physics Shanghai Institute of Optics and Fine MechanicsChinese Academy of Sciences

We report the initial test results of a rubidium （87Rb） space cold atom clock （SCAC）. The space-qualified ST Rb SCAC is composed of the physical package, the optical bench, the microwave synthesizer and the control electronics. After the system is integrated, about 108 ST Rb cold atoms are captured by magneto-optical trap. The linewidth of the Ramsey fringe is about lO Hz for the free evolution time of 50ms on the ground, and the signM-to-noise ratio is measured to be larger than 300. We demonstrate a good medium-term fractional frequency stability of 1.5×10^-14@1000s in the closed-loop operation on the ground. The main effects of the noise on the stability are a/so presented, and the optimized operating parameter is analyzed for the operation of SCAC in the microgravity environment.

关键词： of on in is for Rb been MOT

Optimization of polarization spectroscopy for rubidium D lines

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Chinese Physics B 2013年第2期22卷 271-275页

作者：孙剑芳尹士奇徐震洪涛王育竹 Key Laboratory for Quantum Optics Center for Cold Atom PhysicsShanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences

Polarization spectroscopy of the D lines of rubidium atoms is investigated experimentally,especially with different pump powers and cell *** find that there are four candidate transitions suitable for frequency stabilization,and optimal pump powers and cell temperatures are also presented to obtain a perfect signal with maximal amplitude and *** optimal signal is insensitive to the fluctuations of laser power and the temperature,which can enhance the performance of frequency locking.

关键词： polarization spectroscopy pump power temperature

Pulsed Laser Deposition of VO_(2)Single Crystal Thin Films on Sapphire Substrates

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Chinese Physics Letters 1998年第12期15卷 904-906页

作者： ZHU Pei-ran S.Yamamoto A.Miyashita H.Naramoto institute of Physics Chinese Academy of SciencesBeijing 100080 Department of Materials Development Japan Atom Energy Research InstituteWatanuki 1233TakasakiGumma 370-12Japan

Thin films of VO_(2)single-crystalline on(0001)sapphire substrates have been prepared by visible pulsed laser ablation *** crystal quality and properties of the films are evaluated through electrical resistance measurement,x-ray diffraction(XRD),and Rutherford-backscattering spectroscopy/channeling(RBS/C)*** dependence of the surface electrical resistance of the films on the temperature shows semiconductor-to-metal transitions with the resistance change of 7×10^(3)-2×10^(4).The hysteresis widths are from less than 1 to 3 *** and RBS/C data reveal that the films prepared in particular conditions are single-crystalline VO_(2)with the(010)planes parallel to the surface of the sapphire substrate.

关键词： technique. sapphire Crystal

Dynamic splitting and merging of an atom cloud on an atom chip

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Chinese Physics B 2009年第11期18卷 4823-4828页

作者：柯敏颜波程峰王育竹 The Laboratory of Quantum Optics Shanghai Institute of Optics and Fine MechanicsChinese Academy of Sciences Center for Cold atom Physics Chinese Academy of Sciences

Chip-based atom interferometers bring together the advantages of atom chips and Bose-Einstein condensates. Their central prerequisite is that a condensate can be coherently split into two halves with a determined relative phase. This paper demonstrates the dynamical splitting and merging of an atom cloud with two U-wires on an atom chip. Symmetrical and asymmetrical splittings are realized by applying a bias field with different directions and magnitudes. The trajectories of the splitting are consistent with theoretical calculations. The atom chip is a good candidate for constructing an atom interferometer.

关键词： atom chip dynamic splitting and merging chip-based atom interferometers