bluuebunny/crossref_metadata_2025 huggingface dataset:
A new approach to extract reliable intensities of non-equivalent systematical overlapping reflections from powder diffraction data
Authors: Ma Hong-Wei  , Liang Jing-Kui  ,   (1)中国科学院物理研究所,北京 100080; (2)中国科学院物理研究所,北京 100080;中国科学院国际材料物理中心,沈阳 110016
Published: December 2020

A new approach to extract reliable intensities from systematical non-equivalent overlapping reflections has been proposed and tested by simulated powder diffraction pattern of known structures. By using both crystallographic and structural chemistry knowledge, the IDM-UAIC reconstructs the intensities and solves the structure through an iterative procedure. The results show that IDM-UAIC succeeds when more than 30% of the total scattering power can be located in a reasonable precise from the equivalent systematical overlapping reflections. The IDM-UAIC procedure is superior to the simple equi-partition methods for the nonequivalent systematical overlapping reflections while it is equivalent to simple equi-partition methods for the equivalent systematical overlapping reflections.
Study of gas-solid interface via low-energy pulsed electron beams
Authors: Zhang Tong  , Hu An  , Wu Qiang  , Mao Fu-Ming  , Yang Xue-Qian  , Cui Yi-Ping  ,   (1)东南大学电子工程系,南京 210096; (2)东南大学电子工程系,南京 210096;南京大学固体微结构物理国家重点实验室,南京 210093; (3)南京大学固体微结构物理国家重点实验室,南京 210093; (4)南京师范大学数学与计算机科学学院,南京 210097
Published: December 2020

The principle and method for gas-solid interface study via low-energy pulsed electron beams are introduced, and the processes of adsorption-desorption and displacement are experimentally investigated. The desorption yields, threshold energies, and cross sections for N2 and O2 from polycrystalline Ni and W in vacuum (1×10-3Pa) at (T=300K) are measured. At the end of the paper, the conclusions are given.
A new Pr-based bulk metallic glass and its properties
Authors: Zhao Zuo-Feng  , Zhang Zhi  , Li Zheng  , Wen Ping  , Zhao De-Qian  , Pan Ming-Xiang  , Wang Wan-Lu  , Wang Wei-Hua  ,   (1)中国科学院物理研究所，北京 100080; (2)重庆大学数理学院，重庆 400044; (3)重庆大学数理学院，重庆 400044;中国科学院物理研究所，北京 100080
Published: December 2020

A new rare-earth Pr-based bulk metallic glass (BMG) is obtained in the shape of rod up to 5 mm in diameter by die cast. Unlike other rare-earth based BMGs, it exhibits a distinct glass transition, Tg=409K,the lowest glass transition temperature among the known BMGs, a large and stable supercooled liquid region and paramagnetic property. The glass transition as well as its kinetic nature and the fragility parameters m of the BMG have been studied. The BMG offers an ideal model to investigate the nature of glass transition as well as the relaxation and nucleation with a large experimentally accessible time and temperature window at very low temperature region.
Fabrication, morphology and structure of carbon nanotube arrays and bundles fabricated by a three-step rising temperature procedure
Authors: Cao Pei-Jiang  , Gu You-Song  , Liu Fei  , Liu Hong-Wen  , Zhang Qi-Feng  , Wang Yan-Guo  , Gao Hong-Jun  ,   (1)北京大学电子学系，北京 100871; (2)北京科技大学材料物理系，北京 100083; (3)中国科学院物理研究所，北京 100080
Published: December 2020

In a simple-structured single-temperature furnace, a three-step rising temperature process has been used to fabricate carbon nanotube (CNT) arrays and carbon nanotube bundles by pyrolysis of ferrocene/melamine mixtures on silica and ceramic wafers, respectively. The structure and composition of the CNTs are investigated by scanning electron microscopy, transmission electron microscopy, x-ray photoelectron spectroscopy and electron energy-loss spectroscopy (EELS). EELS spectrum shows that CNTs grown on the two different kinds of substrates are pure carbon tubes. CNTs on smoothing silica wafer are highly orientated and have uniform outer diameters of about 22 nm and varying lengths from 10 to 40 μm. CNTs grow in top growth mode and exhibit the stacked-cup-like structures. CNT bundles on rough ceramics wafer are randomly orientated. They have varying outer diameters of 15—80nm and lengths up to one hundred of micrometers. They exhibit two types of shapes, bell-like and dome-like. The effect of substrate morphologies on the morphology and structure of CNTs has been discussed.
Thermodynamic calculation of energy consumed for boundary friction during martensitic transformation in single crystal Ni2MnGa
Authors: Cui Yu-Ting  , Zhu Ya-Bo  , Liao Ke-Jun  , Wang Wan-Lu  ,   (1)重庆大学应用物理系，重庆 400044; (2)重庆大学应用物理系，重庆 400044;中国科学院物理研究所磁学国家重点实验室，北京 100080
Published: December 2020

Based on the boundary friction phenomenological theory,a general equation for calculating the thermodynamic parameters of Ni2MnGa system was deduced.According to the measured results of the ac magnetic susceptibility or strain during the martensitic transformation for three non-stoichiometric Ni2MnGa single crystal samples with martensitic transition occurring at temperatures below,near,and above room temperature,respectively,the energies consumed for boundary friction in the three samples during their martensitic transformations were calculated using the general equation.It was also indicated that the thermal hysteresis of martensitic transformation originates from the friction of phase boundary motion;moreover,the large differences of the energy consumed for boundary friction and the thermal hysteresis result from the different structures of martensites produced for the three samples during the martensitic transformation.
Growth of single domain monatomic In chain arrays on vicinal Si(001) surface
Authors: Dou Rui-Fen  , Jia Jin-Feng  , Xu Mao-Jie  , Pan Ming-Hu  , He Ke  , Zhang Li-Juan  , Xue Qi-Kun  ,   中国科学院物理研究所表面物理国家重点实验室，北京 100080
Published: December 2020

Using a vicinal Si(001) surface with 4°miscut along ［110］ direction as a substrate, we have fabricated single-domain monatomic In chain arrays on a large scale. High-resolution scanning tunneling microscopic images reveal that the deposited In atoms preferentially form In dimers between the two neighboring Si dimer rows on the lower terrace along the step edge, due to the high coordination of these positions. Indium dimers remove dangling bonds of the Si dimers and saturate all In valency,andthen develop into a long monatomic In chain along the step edge. It is worth highlighting that the ordered narrow terrace and the straight DB steps edge are key to the formation of the monatomic In chains.
In situ investigation of structural properties during formation of pentacene thin film on Ag (110) with MBE-LEED
Authors: Wang Ye-Liang  , Shi Dong-Xia  , Ji Wei  , Du Shi-Xuan  , Guo Hai-Ming  , Liu Hong-Wen  , Gao Hong-Jun  ,   中国科学院物理研究所，北京 100080
Published: December 2020

The structural transition of pentacene thin films on single Ag (110) crystals has been directly observed using a home-designed in situ low-energy electron diffraction during the course of absorption and subsequently changes of substrate temperature.The pentacene moleculs showed the evolution from disordered structure in the submonolayer region to a well-ordered structure in the monolayer on the substrate at room temperature.The experimental and theoretical results showed that the molecules lay flat on the Ag (110) surface with two domain orientations mirrored with respect to the crystal axis of the silver substrate.Furthermore, the ordered structures can keep stable when the substrate temperature is below the sublimation temperature of pentacene.
Fullerene-like nano-crystalline CNx films and its characteristics of field electron emission
Authors: Zhang Lan  , Ma Hui-Zhong  , Li Hui-Jun  , Yang Shi-E  , Yao Ning  , Hu Huan-Ling  , Zhang Bing-Lin  ,   (1)郑州大学工程力学系，郑州 450002; (2)郑州大学工程力学系，郑州 450002;中国科学院安徽光学精密机械研究所，合肥 230031; (3)郑州大学物理工程学院，郑州 450052; (4)中国科学院安徽光学精密机械研究所，合肥 230031
Published: December 2020

CNx films were prepared by using microwave plasma-enhanced chemical vapor phase deposition. As-deposited films were analyzed by x-ray photoelectron spectroscopy, x-ray diffraction, scanning electron microscopy and Raman spectroscopy. Field electron emission characteristics of thin films were studied. Experimental results indicate that the film structure and properties of the field electron emission are related to flow ratio of N2 to H2 while the flow rate of CH4 was kept at 8 sccm. When the flow ratio of N2 to H2 was 50/50 sccm, the obtained film had a nano-crystalline graphitic structure with curved basal planes (fullerene-like structure) and excellent properties of field electron emission. The turn-on field decreased to 1.1 V/μm. At an electric field of 5.9V/μm, the average current density was 70μA/cm2 and emission sites density was larger than 1×104cm-2.
Study on the definite direction growth of carbon nanotubes by the microwave plasma-enhanced chemical vapro phase deposition
Authors: Wang Miao  , Li Zhen-Hua  , Takegawa Hitosi  , Saito Yahachi  ,   (1)日本三重大学工学部，津 514-8507; (2)浙江大学力学系，杭州 310027; (3)浙江大学物理系，杭州 310027;日本三重大学工学部，津 514-8507
Published: December 2020

Using the microwave plasma-enhanced chemical vapor phase deposition,in the gas mixture of the methane and hydrogen, the aligned growth of the carbon nanotubes was observed and analyzed with a scanning electron microscope.The carbon nanotubes have the tidy arrangement in the perpendicular direction on a solid substrate.Its length is the same as the uniform caliber.This kind of carbon nanotubes can be used as the potential electron source material.
Study on fabrication of sol-gel glass containing chiral micro-crystal and its depolarization
Authors: Tao Wei-Dong  , Dong Jian-Feng  , Xia Hai-Ping  , Bai Gui-Ru  , Lu Zu-Kang  ,   (1)宁波大学光电子功能材料研究室，宁波 315211; (2)宁波大学光纤通信与网络技术研究所，宁波 315211; (3)浙江大学现代光学仪器国家重点实验室，杭州 310027
Published: December 2020

By dry crush way, the bulk chiral crystal was smashed to chiral micro-crystal which particle size was 70μm. The chiral micro-crystal was disseminated homogeneously in the gel by sol-gel process. So sol-gel glass containing chiral micro-crystal which thickness was 4 mm has been manufactured successfully. It was found that sol-gel glass containing chiral micro-crystal displayed its depolarization effect. We replaced the chiral micro crystal by glass powder which particle size was also 70 μm, and manufactured the sol-gel glass containing glass powder by the same way. It was found that the sol-gel glass containing glass powder displayed its polarization-held characteristic. The cause was analyzed.
Crystal growth of quasi-two-dimensional purple bronze KxMo6O17
Authors: Wang Jun-Feng  , Xiong Rui  , Yu Heng  , Li Hui  , Tang Wu-Feng  , Yu Zu-Xin  , Shi Jing  , Tian De-Cheng  , Tian Ming-Liang  , Zhang Yu-Heng  ,   (1)武汉大学物理科学与技术学院，武汉 430072; (2)武汉大学物理科学与技术学院，武汉 430072;中国科学院国际材料物理中心，沈阳 110016; (3)中国科学技术大学结构分析中心，合肥 230026
Published: December 2020

Purple bronze KxMo6O17 single crystals are successfully grown by electrolytic reduction method from the melts of K2CO3 and MoO3.The detailed process of the preparation is reported.The structure of the single crystals are investigated with x-ray diffraction and Transmission electron microscope.The results show that the crystals have large sizes and high qualities.The unit cell parameters are:a=b=0.5540nm,c=1.3508nm，and the crystal structure is refined to be trigonal with space group P3.The temperature dependence of resistance reveals that the compounds undergo Peierls phase transition at 112K.
Cu-W Thin film characterized by surface fractal and resistivity
Authors: Wang Yuan  , Xu Ke-Wei  ,   (1)西安交通大学金属材料强度国家重点实验室,西安 710049; (2)西安交通大学金属材料强度国家重点实验室,西安 710049;兰州铁道学院机械与动力学院,兰州 730070
Published: December 2020

Thin films of Cu-W were deposited on Si wafers by magnetron sputtering,and characterized by atomic force microscopy(AFM).Power spectra density was used to calculate the fractal dimension of the AFM images.The results show that the fractal dimension values increase with the film thickness and there is a relationship between the fractal dimension and the resistivity of the films.The change of resistivity is directly proportional to the fractal dimension.
The magnetic anisotropic effect on giant magnetoimpedance in sandwiched films
Authors: Wang Ai-Ling  , Liu Jiang-Tao  , Zhou Yun-Song  , Jiang Hong-Wei  , Zheng Wu  ,   首都师范大学物理系，北京 100037
Published: December 2020

The sandwiched film structured by two soft magnetic layers with the Cu layer as the central one is proposed,which is based on the experimental samples of giant magnetoimpedance (GMI) effect.Its characteristics are discussed theoretically using Maxwell equations and Landau-Lifshitz equation wiuh calculating the anisotropy of the magnetic layers.Application of the theoretical model to real materials is examined.Predictions of the model compare well qualitatively with experimental data.The anisotropic constant Hk of the magnetic layer is very important.The GMI effect is modified by both the magnitude and the orientation of Hk.The best Hk is about 400A/m along the normal to the current.It is also proved that any magnetostriction in the magnetic layer of the sandwiched film damages the GMI effect.
Optimizing boron implantation dose of HgCdTe infrared detectors
Authors: Chen Gui-Bin  , Lu Wei  , Cai Wei-Ying  , Li Zhi-Feng  , Chen Xiao-Shuang  , Hu Xiao-Ning  , He Li  , Shen Xue-Chu  ,   (1)中国科学院上海技术物理研究所红外物理国家重点实验室，上海 200083; (2)中国科学院上海技术物理研究所红外物理国家重点实验室，上海 200083;中国科学院上海微系统与信息技术研究所离子束开放研究实验室，上海 200050
Published: December 2020

Using the material chip technology,large area photodiodes of n-on-p structure with different boron implantation dose are fabricated on the Hg1-xCdxTe film for mid-infrared wavelength region(x=0.291).Current-voltage characteristics of the photodiodes are measured at 77K and zero bias resistance-area products of different photodiodes are fitted from the data in the voltage range of -0.2—0.08V.The study indicated that the R0A products of different elements depended distinctly upon the implanted boron dose.A large R0 value has also obtained in another chip with x=0.2743.All the samples in this study are grown by Riber 32P molecular-beam epitaxy system and all the junctions-forming process is same to the standard planar technology but using a series of metallic masks during the boron ion implantation.
X-ray photoemission studies of Yb intercalated C60 thin film
Authors: He Shao-Long  , Li Hong-Nian  , Li Hai-Yang  , Zhang Han-Jie  , Lü Bin  , He Pi-Mo  , Bao Shi-Ning  , Xu Ya-Bo  ,   浙江大学物理系，中心实验室，杭州 310027
Published: December 2020

Yb-intercalated C60 thin film was prepared in a ultra-high-vacuum system. The binding energies of C 1s, Yb 4f and Yb 4d during the compound formation were studied by x-ray photoemission technique. The stoichiometry of the phase-pure sample was determined by the peak intensities of Yb 4f and C 1s. The result turned to be very near to that for Yb2.75C60 that was first determined for bulk-phase sample by x-ray diffraction measurement. The positions and intensities of the Yb 4f and Yb 4d peaks revealed the charge state of Yb2+ in Yb2.75C60. The C 1s core level for the phase-pure sample shifted towards lower binding energy by ≈0.5 eV relative to C60, which exhibited that some Yb 6s electrons transferred from Yb to the lowest unoccupied molecular orbital band of C60. The shift and the FWHM of C 1s x-ray photoemission spectroscopic peak can be used as sample characterization in future researches on Yb/C60 compounds.
Study on the electronic structure and superconductivity of MgCNi3
Authors: Chen Li  , Li Hua  ,   (1)山东大学物理与微电子学院，济南 250100; (2)山东大学物理与微电子学院，济南 250100;临沂师范学院物理系，临沂 276005
Published: December 2020

The electronic structures and superconductivity of a new superconducting perovskite material MgCNi3 are studied using MS-Xα calculation. In MgCNi3, the peak of density of states is located below the Fermi level, which is dominated by Ni d band. The electronic structures of MgCNi2T(T=Co，Mn，Cu) have been also investigated. It is confirmed that Co dopants in MgCNi3 behave as a source of d-band holes, and the suppression of superconductivity occurs faster for the Mn-doped case than for the Co-doped case. We study the effects of electron (Cu) doping on the superconductivity. It is found that both electron (Cu) doping and hole (Co, Mn) doping quench superconductivity. Comparing with the hole (Co) doping, we found that the suppression of superconductivity occurs faster for the Co-doped case than for the Cu-doped case.
Substitution effect of Ta in EuSr2Ru1-xTaxCu2O8 system
Authors: Fang Ming-Hu  , Lin Yang-Fan  , Lu Jun-Sheng  , Zhang Guo-Fang  , He Qing  , Wang Hang-Dong  ,   (1)南阳师范学院物理系,南阳 473061; (2)浙江大学物理系,杭州 310027; (3)浙江万里学院基础部,宁波 315100
Published: December 2020

The measurements on the structure, resistance and magnetization were carried out for EuSr2Ru1-xTaxCu2O8 (x=0.0, 0.1, 0.2, 0.5 and 1.0) samples. It is found that the EuSr2RuCu2O8 compound exhibits a ferromagnetic order of Ru moments below Tc=130.2K, and becomes superconducting at a much lower temperature Tc=35K, and shows the typical characteristics of underdoped high-Tc superconductors. The ferromagnetic transition temperature and superconducting transition temperature decrease with increasing the substitution concentration x value of Ta for Ru. The effect of element substitution, the coexistence of magnetism and superconductivity in this system are discussed in detail.
Time telescope for the expanding of ultrashort pulses
Authors: Xu Guang  , Qian Lie-Jia  , Wang Tao  , Zhu He-Yuan  , Fan Dian-Yuan  ,   (1)复旦大学先进光子学材料与器件国家重点实验室，上海 200433; (2)中国科学院上海光学精密机械研究所，上海 201800; (3)中国科学院上海光学精密机械研究所，上海 201800;复旦大学先进光子学材料与器件国家重点实验室，上海 200433
Published: December 2020

In this paper we have theoretically investigated the time telescope that offers a function of pulse expanding. Time telescope, with features of high efficiency and near Fourier-transform limit, is constructed mainly by using nonlinear parametric conversions of chirped pulses. Based on both analytical and numerical studies, it is found that group-velocity mismatch of the nonlinear crystal plays an important role in temporal aberration and conversion efficiency, and the criteria for designing a near aberration-free telescope are summarized. Finally, it is experimentally demonstrated that a 70fs short pulse is expanded to a 60ps long pulse near Fourier-transform limit.
Optical absorption of Au/BaTiO3,Fe/BaTiO3 nanocomposite films prepared by PLD
Authors: Wang Wei-Tian  , Yang Guang  , Guan Dong-Yi  , Wu Wei-Dong  , Chen Zheng-Hao  ,   (1)中国工程物理研究院激光聚变研究中心，绵阳 621900; (2)中国科学院物理研究所光物理开放实验室，北京 100080; (3)中国科学院物理研究所光物理开放实验室，北京 100080;中国工程物理研究院激光聚变研究中心，绵阳 621900
Published: December 2020

Nanocomposite thin films formed by nanometer-sized metal particles embedded in BaTiO3 matrices (Au/BaTiO3,Fe/BaTiO3) were fabricated using pulsed laser deposition technique.The morphology and chemical state of the embedded metal particles were analyzed by transmission electron microscopy and x-ray photoelectron spectroscopy,respectively.The absorption peak due to the surface plasmon resonance of Au particles was observed at the wavelength of about 580nm in Au/BaTiO3 films.However,optical absorption spectra in the wavelength range of 330—800nm showed no significant resonance peak in Fe/BaTiO3 films.The results were explained by Mie theory.
The effect of hydrogen and nitrogen on the growth of boron carbonitride nanotubes
Authors: Chao Ming-Ju  , Ding Pei  , Zhang Hong-Rui  , Guo Mao-Tian  , Liang Er-Jun  ,   郑州大学物理工程学院，材料物理国家教育部重点实验室,郑州 450052
Published: December 2020

On the basis of the study of different temperature and catalyst, the effect of hydrogen and nitrogen on the morphology and yield of boron carbonitride(BCN) nanotubes produced by thermal decomposition at 860℃ was studied. It is found that nitrogen has a little effect on the growth of BCN nanotubes. Different from nitrogen, transmission electron microscopy(TEM) images reveal that hydrogen is important to the growth of BCN nanotube. Bamboo-shaped thinner wall nanotubes with higher yield are produced with hydrogen flow rate of 40 sccm, whereas curved nanotubes with lower yield and are generated with hydrogen flow rate of 0 sccm. BCN nanotubes with some holes on were produced with the flow rate of 80 sccm. Basic on previous analysis, we think that the appropriate range of N2 should be 150—210 sccm, and that of H2 should be about 40 sccm. At last, the reasons were also analysised.
Luttinger parameter of carbon nanotubes investigated by shot noise experiment
Authors: Zhang Zhi-Yong  , Wang Tai-Hong  ,   中国科学院物理研究所，北京 100080
Published: December 2020

Fermi liquid model with elemental charge of e*(e*=ge) is used to describe the electrical transport in carbon nanotubes, so the scattering theory can be used to calculate the zero-frequency shot noise in nanotubes. When the temperature is 0K, the nanotube with a strong barrier has the shot noise of 2geI. A new approach to measure the Luttinger g-factor of nanotubes is created: forming a strong barrier in nanotube, measuring its shot noise S, and then calculating the g-factor.
The influence of thermal effects in a beam control system and spherical aberration on the laser beam quality
Authors: Ji Xiao-Ling  , Tao Xiang-Yang  , Lü Bai-Da  ,   (1)四川大学激光物理与化学研究所，成都 610064; (2)四川大学激光物理与化学研究所，成都 610064;江西师范大学物理与通信电子学院，南昌 330027; (3)四川大学激光物理与化学研究所，成都 610064;四川师范大学电子工程学院，成都 610066
Published: December 2020

With the strehl ratio, power in the bucket, β parameter and beam widths taken as the characteristic parameters of laser beam quality in the far field, the influence of thermal effects in a beam control system and spherical aberration on the laser beam quality in the far field is studied. Detailed calculations are performed using a four-dimensional simulation code, and numerical results are given and analyzed physically. It is shown that the thermal effects in the propagation channel and positive spherical aberration give rise to an expansion of intensity distributions and reduce the focus ability in the far field, and degrade the beam quality. It is interesting that a suitable choice of the negative spherical aberration would result in a higher peak intensity and a better focus abilty at the geometrical focal plane than that of the spherical-aberration-free case, as the emissive power reaches a certain value; whereas a similar result is achieved at the real focal plane due to the focal shift as in the previous work. The physical interpretation is that there exists the nonlinear thermal blooming, which is illustrated with numerical examples.
A study of characteristics for deep dielectric charging on satellites
Authors: Huang Jian-Guo  , Chen Dong  ,   中国科学院空间科学与应用研究中心，北京 100080
Published: December 2020

Deep dielectric charging is one of the key factors that induce malfunction and failure on geosyncronous satellites. In this paper, the relations between the maximum electric field generated during charging and high energy spectrum, thickness of dielectric and that of shield applied are studied, and the main characteristics about the maximum electric field are provided
Effects of target thickness on spectral characteristics of x-ray flux from the laser-produced plasmas
Authors: Wang Wei  , Zhang Jie  , Dong Quan-Li  , V.K.Senecha  ,   (1)Laser Plasma Division,Centre for Advanced Technology,Indore-452013,India; (2)中国科学院物理研究所光物理开放实验室，北京 100080; (3)中国科学院物理研究所光物理开放实验室，北京 100080;首都师范大学物理系，北京 100037
Published: December 2020

A detailed numerical simulation study of spectral characteristics of the x-ray flux from gold foil targets of different thickness irradiated by a 1ns laser pulse with 1014W/cm2 intensity at 0.35μm wavelength using the one dimensional radiation hydrodynamic code MULTI is investigated using one dimensional radiation hydrodynamic code MULTI.This is very important in the diagnosis of the x-ray spectrum and the design of an x-ray source.
Explicit expressions and recurrence formulas of the radial average values for a kind of nonharmonic oscillator model potentials
Authors: Chen Chang-Yuan  , Lu Fa-Lin  , Sun Dong-Sheng  , Liu Cheng-Lin  ,   盐城师范学院物理系，盐城 224002
Published: December 2020

In this paper, two recurrence formulas are derived for the radial average values of a kind of non-harmonic oscillator model potentials; these non-harmonic oscillator model potentials are ring-shaped non-spherical oscillator, non-spherical oscillator, and ring-shaped oscillator. Explicit expressions for their radial average values are given.
Calculation of the ground-state energies of hydrogen-like impurity in a lens-shaped quantum dot
Authors: Chang Jia-Feng  , Zeng Xiang-Hua  , Zhou Peng-Xia  , Bi Qiao  ,   扬州大学物理科学与技术学院,复杂性科学中心,扬州 225002
Published: December 2020

Compared with the spherical quantum dot, the ground-state energies of hydrogen-like impurity in a lens-shaped quantum dot (GaAs/In1-xGaxAs) under vertical magnetic field have been discussed by using effective mass approximation and variational method. It is found that for the spherical quantum dot, the ground-state energy is only related with the deviation of distance of the impurity, but not with the in-plane or perpendicular deviation. For a lens-shaped quantum dot, due to the asymmetry of the bound potential of in-plane and perpendicular to the plane, the electronic ground-state energies are related not only with the deviation of distance but also with the deviation of direction.
Thermodynamic properties of a weakly interacting Fermi gas
Authors: Su Guo-Zhen  , Chen Li-Xuan  ,   厦门大学物理系，厦门 361005
Published: December 2020

The analytical expressions of chemical potential, total energy and heat capacity at a constant volume for a weakly interacting Fermi gas in the absence of external potential are derived by using “pseudopotential” method. Based on the derived expressions, the thermodynamic properties of a weakly interacting Fermi gas trapped in a harmonic potential are studied under the local-density approximation. The effects of interparticle interactions on the properties of the systems are discussed.
Numerical study for transient SBS process in transparent optical materials
Authors: Guo Shao-Feng  , Lu Qi-Sheng  , Cheng Xiang-Ai  , Li Quan  , Zeng Xue-Wen  , Yin Yan  ,   国防科技大学理学院定向能技术研究所，长沙 410073
Published: December 2020

Theoretical model is established to study the Stimulated Brillouin Scattering (SBS) process with both noise initiation and seeding Stokes laser assisted initiation.Multi-steps finite difference method is adopted to solve coupled wave equations numerically, and the temporal and spatial profiles of scattered light intensity and density variations of the medium are obtained. The dependence of Stokes laser on SBS reflectivity and initiation thresholds is investigated.It is found that the time needed for SBS initiation decreases sharply since the seeding Stokes laser is introduced. Finally, the damage potential of the SBS process in optical materials is evaluated and future work is outlined.
Low-dimensional Bose-Einstein condensation in finite-number trapped atoms
Authors: Cui Hai-Tao  , Wang Lin-Cheng  , Yi Xue-Xi  ,   东北师范大学理论物理研究所，长春 130024
Published: December 2020

The effect of finite number of trapped atoms is discussed in Bose-Einstein condensation without interaction, according to Thomas-Fermi approximation. We obtain the state density by high-temperature expansion and calculate the critical temperature in one-dimensional(1D) and two-dimensional(2D) trap potentials. Then the temperature dependence of specific heat are analyzed. The results show that: in 2D case, the specific heat c is proportional to T2; in 1D case,c increases linearly with temperature.
Perturbed solution for the ENSO nonlinear model
Authors: Mo Jia-Qi  , Lin Wan-Tao  ,   (1)安徽师范大学数学系，芜湖 241000; (2)中国科学院大气物理研究所，北京 100029
Published: December 2020

A class of ENSO perturbed model is studied. Using the perturbation theory and method, the asymptotic expansions of solution of corresponding problem are constructed.
Analytical design of the observer-based chaotic generalized synchronization
Authors: Li Guo-Hui  ,   上海大学通信与信息工程学院，上海 200072
Published: December 2020

This paper develops a modified state observer for chaotic generalized synchronization. An analytic approach is proposed for constructing a response system to implement generalized chaos synchronization with drive system. From the state observer theory, some sufficient conditions of global asymptotic linear-generalized synchronization between the drive system and response system are obtained. Finally, a hyperchaotic R?ssler system is given to illustrate the effectiveness of the proposed synchronization method.
Transition‐Metal‐Mediated and Transition‐Metal‐Catalyzed Carbon–Fluorine Bond Formation
Authors: Neumann Constanze N. , Ritter Tobias
Published: December 2020

The number and diversity of methods for installing carbon–fluorine bonds have substantially expanded over the past two decades, enabling enantioselective fluorinations, reactions with complex substrates, and the use of ever simpler reaction precursors. Fluorination chemistry was long held back by unreactive alkali fluoride salts and highly reactive electrophilic fluorine sources, such as molecular fluorine and cobalt(III) fluoride. The introduction of fluorination reagents with controlled reactivity has been a key driving force in harnessing the reactivity of fluoride, as has the strategic use of transition metals. These approaches enable predictable and functional‐group‐tolerant carbon–fluorine bond formation. Herein, transition‐metal‐catalyzed and transition‐metal‐mediated syntheses of aromatic, heteroaromatic, and alkyl fluorides are reviewed. In addition, methods for allylic fluorination, benzylic fluorination, and fluorination α to carbonyl groups are presented. The influence of these reactions on the synthesis of complex fluorinated molecules and the preparation of
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F‐PET probes are described, and experimental procedures for illustrative examples are included.
Trehalose induces SQSTM1/p62 expression and enhances lysosomal activity and antioxidative capacity in adipocytes
Authors: Kobayashi Masaki , Yasukawa Hiromine , Arikawa Tomoya , Deguchi Yusuke , Mizushima Natsumi , Sakurai Misako , Onishi Shoichi , Tagawa Ryoma , Sudo Yuka , Okita Naoyuki , Higashi Kyohei , Higami Yoshikazu
Published: December 2020

Adipocytes, which comprise the majority of white adipose tissue (WAT), are involved in obesity‐related pathology via various mechanisms, including disturbed lysosomal enzymatic activity and accumulation of oxidative stress. Sequestosome 1 (SQSTM1/p62) is an autophagy marker that participates in antioxidative responses via the activation of nuclear factor erythroid‐derived 2‐like 2 (NRF2). Trehalose is a non‐reducing disaccharide reported to suppress adipocyte hypertrophy in obese mice and improve glucose tolerance in humans. We recently revealed that trehalose increases SQSTM1 levels and enhances antioxidative capacity in hepatocytes. Here, to further evaluate the mechanism behind the beneficial effects of trehalose on metabolism, we examined SQSTM1 levels, autophagy, and oxidative stress in trehalose‐treated adipocytes. We initially confirmed that trehalose increases SQSTM1 transcription and protein levels without affecting autophagy in adipocytes. Trehalose also elevated transcription of several lysosomal genes and the activity of cathepsin L, a lysosomal enzyme, independently of the transcription factor EB. In agreement with our data from hepatocytes, trehalose induced the nuclear translocation of NRF2 and the transcription of its downstream antioxidative genes, resulting in reduced cellular reactive oxygen species levels. Moreover, some cellular trehalose was detected in trehalose‐treated adipocytes, implying that extracellular trehalose is taken into cells. These observations reveal the mechanism behind the beneficial effects of trehalose on metabolism and suggest its potential for preventing or treating obesity‐related pathology.
DNA methylation subtypes for ovarian cancer prognosis
Authors: Yin Lili , Zhang Ningning , Yang Qing
Published: December 2020

Ovarian cancer is one of three major malignancies of the female reproductive system. DNA methylation (MET) is closely related to ovarian cancer occurrence and development, and as such, elucidation of effective MET subtype markers may guide individualized treatment and improve ovarian cancer prognosis. To identify potential markers, we downloaded a total of 571 ovarian cancer MET samples from The Cancer Genome Atlas (TCGA), and established a Cox proportional hazards model using the MET spectrum and clinical pathological parameters. A total of 250 prognosis‐related MET loci were obtained by Cox regression, and six molecular subtypes were screened by consensus clustering of CpG loci with a significant difference in both univariate and multivariate analyses. There was a remarkable MET difference between most subtypes. Cluster 2 had the highest MET level and demonstrated the best prognosis, while Clusters 4 and 5 had MET levels significantly lower than those of the other subtypes and demonstrated very poor prognosis. All Cluster 5 samples were at a high grade, while the percentage of stage IV samples in Cluster 4 was greater than in the other subtypes. We obtained five CpG loci using a coexpression network: cg27625732, cg00431050, cg22197830, cg03152385, and cg22809047. Our cluster analysis showed that prognosis in patients with hypomethylation was significantly worse than in patients with hypermethylation. These MET molecular subtypes can be used not only to evaluate ovarian cancer prognosis, but also to fully distinguish the tumor stage and histological grade in patients with ovarian cancer.
Finger Systolic Blood Pressure Index Measurement: A Useful Tool for the Evaluation of Arterial Disease in Patients With Systemic Sclerosis
Authors: Blaise Sophie , Boulon Carine , Mangin Marion , Senet Patricia , Lazareth Isabelle , Imbert Bernard , Lapebie François‐Xavier , Lacroix Philippe , Constans Joël , Carpentier Patrick
Published: December 2020

Objective

To evaluate the prevalence and clinical correlates of peripheral arterial disease of the upper limbs in patients with systemic sclerosis (SSc), as detected with finger brachial pressure index (FBPI) measurements.

Methods

This work is based on the baseline data of the SCLEROCAP multicenter cohort of SSc patients. Finger systolic blood pressure was measured with laser Doppler flowmetry, and the FBPI was obtained as its ratio over the ipsilateral brachial systolic blood pressure. An FBPI of <0.70 was used as the diagnostic criterion for occlusive arterial disease of the upper limbs. Thus, the prevalence of defined arterial disease as well as its clinical, biologic, and capillaroscopic correlates were evaluated.

Results

Among 326 enrolled patients, 177 (54.3%) met the criterion for arterial disease (FBPI <0.70). No association was found with the type of SSc nor with the type of associated antinuclear antibodies, but a significant association was found with the duration of the disease (P < 0.001), the capillaroscopic pattern (P < 0.001), and most strikingly with the presence of digital ulcers (42.9% versus 13.4%; P < 0.001). A quantitative relationship was found between the FBPI and the prevalence of digital ulcers and was shown to be independent from the capillaroscopic pattern.

Conclusion

This cross‐sectional study shows a high prevalence of arterial disease of the upper limbs in patients with SSc. FBPI appears to be a strong and independent predictor of digital ulcers. This study suggests that both macro‐ and microangiopathy are contributing to the ischemic damage of the fingertips.
Chronic Stress and Arthritis: A Scoping Review
Authors: Schwetlik Sarah N. , Baldock Katherine L. , Hill Catherine L. , Ferrar Katia
Published: December 2020

Objective

Emerging research supports the role of chronic stress in chronic disease development. The objective was to perform a scoping review mapping the field of research exploring relationships between chronic stress and the development of arthritis in adult populations.

Methods

Five electronic databases were systematically searched without publication limits based on 3 key concepts: stress, arthritis, and adults. Eligible qualitative studies investigated individuals' perceived causes of arthritis; quantitative studies investigated relationships between exposure to a chronic stressor and an arthritis presence outcome. Articles were screened by 2 independent reviewers, and data were narratively synthesized.

Results

Of 1,819 unique records, 54 studies met inclusion criteria. Nine studies used qualitative methods, and 45 used quantitative methods. The frequency of studies increased chronologically, with half (n = 27) published since 2010. Chronic stress exposures were heterogenous; most were categorized as adverse life events (n = 22) or adverse childhood experiences (n = 17). Self‐reported arthritis was the most frequent measure of arthritis outcome (n = 26) in quantitative studies. A majority of studies (n = 41) suggested a relationship between exposure to chronic stressors and arthritis development.

Conclusion

Increasing study numbers in the past decade may reflect increasing awareness of the potential impact of chronic stress in arthritis development, consistent with a biopsychosocial approach to chronic disease etiology and management. Further research, using precise arthritis definitions, conducted within a clearly articulated pathophysiologic framework, is required to establish a causal relationship between exposure to chronic stressors and the development of specific arthritis conditions.
Racial Disparities in Systemic Sclerosis: Short‐ and Long‐Term Outcomes Among African American Participants of SLS I and II
Authors: Volkmann Elizabeth R. , Steen Virginia , Li Ning , Roth Michael D. , Clements Philip J. , Furst Daniel E. , Assassi Shervin , Khanna Dinesh , Kim Grace‐Hyun J. , Goldin Jonathan , Elashoff Robert M. , Tashkin Donald P.
Published: December 2020

Objective

To evaluate short‐ and long‐term outcomes of African American (AA) participants of Scleroderma Lung Studies (SLS) I and II.

Methods

SLS I randomized 158 participants with systemic sclerosis‐interstitial lung disease (SSc‐ILD) to 1 year of oral cyclophosphamide (CYC) versus placebo. SLS II randomized 142 participants with SSc‐ILD to 1 year of oral CYC followed by 1 year of placebo versus 2 years of mycophenolate (MMF). Joint models compared the course of forced vital capacity (FVC) and diffusing capacity for carbon monoxide (DLCO) between AA and non‐AA, and Cox proportional hazard models assessed long‐term morbidity and mortality outcomes.

Results

In SLS I, there was no difference in the course of the FVC or DLCO between AA and non‐AA in either treatment arm. In SLS II, AA had an improved course of the FVC compared with non‐AA in the CYC arm; in the MMF arm, there was no difference in FVC course. There was no difference in DLCO course in either arm. Time to death and respiratory failure were similar for AA and non‐AA in SLS I. There was a trend for improved survival and time to respiratory failure in AA compared with non‐AA in SLS II. AA race was not independently associated with mortality in the SLS I or II in the Cox models.

Conclusion

Data from two randomized controlled trials demonstrated that AA patients with SSc‐ILD have similar morbidity and mortality outcomes compared with non‐AA patients. These findings contrast with the racial disparities described in prior observational studies and warrant further investigation.
HHS OIG audit of OTPs finds operations impacted by COVID‐19
Authors: Knopf Alison
Published: December 2020

Opioid treatment programs (OTPs, sometimes known as methadone clinics) had many challenges during COVID‐19, an audit by the Office of Inspector General (OIG) of the federal Department of Health and Human Services (HHS) released last month has found.
Halide Perovskite Nanocrystal Emitters
Authors: Liu Maning , Grandhi G. Krishnamurthy , Matta Sri , Mokurala Krishnaiah , Litvin Aleksandr , Russo Salvy , Vivo Paola
Published: December 2020

The increasing attention on halide perovskite nanocrystals (PNCs) stems from their outstanding optoelectronic properties, especially the intriguing photoluminescence (PL) features. The high photoluminescence quantum yields (up to unity) of PNCs, and the tunability of their optical bandgaps by composition engineering and quantum confinement effects, account for the demonstrated great potential in several optoelectronic applications, such as light‐emitting diodes (LEDs), phosphors, lasers, and photodetectors. However, despite the rapid growth of this research field, several questions are still left unanswered and there is room for further improving the luminescence performance, particularly for emerging lead‐free PNC compositions. Herein, the recent advances in the light emission phenomena in PNCs are discussed. A special focus is given to the correlation between PL and phase transition, the dual‐color emission, the tunability of the PL toward near‐infrared (NIR), and the thermal quenching effect. The key research findings on LEDs, the major application of perovskite‐based nanoscale emitters, are also outlined. Finally, the view on the most urgent challenges to be addressed is provided, with the intent of promoting a more profound understanding of PNC emission‐related phenomena in the future.
Electrochemical Regioselective Phosphorylation of Nitrogen‐Containing Heterocycles and Related Derivatives
Authors: Deng Yong , You Shiqi , Ruan Mengyao , Wang Ying , Chen Zuxing , Yang Guichun , Gao Meng
Published: December 2020

The site‐selective functionalization of biologically important nitrogen‐containing heterocycles and related derivatives remains a challenging and important task. We report herein on the direct regiodivergent N1/C2 phosphorylation of free indole derivatives. Cyclic voltammograms and EPR data indicate that by utilizing different electrolyte‐mediated anodic oxidation to generate different active indole species, a diverse collection of N1 and C2 phosphorylation products could be obtained in moderate to high yields under exogenous‐oxidant‐free and metal‐catalyst‐free electrochemical conditions. In addition, N−P coupling was also found to be compatible with various alkylamines.

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Phylogenetic signal and climatic niche of stem photosynthesis in the mediterranean and desert regions of California and Baja California Peninsula
Authors: Ávila‐Lovera Eleinis , Garcillán Pedro P.
Published: December 2020

PREMISE

Woody plants with photosynthetic stems are common in the drylands of the world; however, we know little about the origin(s) and geographical distribution of photosynthetic stems. Therefore, we set to answer the following questions: (1) Is stem photosynthesis phylogenetically conserved? (2) Do green‐stemmed and fleshy‐stemmed species have identifiable climatic niches?

METHODS

We mapped the photosynthetic stem trait onto a phylogeny of 228 mediterranean and desert species and calculated indices of phylogenetic signal and created climatic niche models of 28 species belonging to three groups: green, fleshy, and green‐and‐fleshy stemmed species.

RESULTS

We found phylogenetic signal in the fleshy stem trait, but not in the green stem trait. Fleshy‐stemmed species occupy areas associated with high isothermality, high precipitation seasonality, and high mean temperature of the wettest quarter, whereas green‐stemmed species occupy areas associated with high precipitation of driest month, high precipitation of coldest quarter, high mean diurnal temperature range and high maximum temperature of the warmest month.

CONCLUSIONS

Despite the fact that both photosynthetic stem types help cope with water shortage, having fleshy stems allows plants to cope with greater precipitation seasonality than is possible with green stems. Green stems require a lot of water to be stored in the soil to maintain net photosynthesis during the dry season, so they inhabit areas with higher and more predictable precipitation.
Backpack health reduces data‐sharing barriers between the medical community and individuals with rare diseases
Authors: May Lauren , Towne Meghan C. , Haynes Ginger , Dalton Emily , LaDuca Holly , Masciale Eileen , Stephens Kim J. , Hogan Melissa , Shapiro‐Barr Michael , Sheedy Roughan , Smith Erin
Published: December 2020

Technology has changed the way we approach medical care: health data is constantly being generated, medical discoveries are progressing more rapidly, and individuals are more connected across the world than ever before. Backpack Health is a global personal health record platform that harnesses the power of technology to connect users to their primary health data sources, the medical community, and researchers. By syncing with existing patient portals, health data can be stored on the Backpack Health platform and easily accessed and controlled by users in one connected interface. Individuals manage and collate their current and past conditions, genetic test results, symptoms, medications, procedures, labs, and other health data. Users are empowered to disseminate their information to clinicians, researchers, foundations, and pharmaceutical and biotechnology companies they connect with through the Backpack Health application. Here, we describe how two rare disease advocacy groups, The Marfan Foundation and Project Alive, utilize Backpack Health to connect with their target populations. Through secure transfer of pseudonymized data, groups can query their members to improve understanding of clinical features and to facilitate meaningful research. Responses to the groups' surveys show strong member engagement with high completion rates and increases in new Backpack Health users when surveys are deployed. Data from these surveys have been published and used to better inform clinical outcomes for treatment trials. By connecting users directly to the foundations, clinicians, researchers, and industry partners working on their condition, Backpack Health is instrumental in fast‐tracking medical discoveries and treatment for rare diseases.
1,3,4‐Oxadiazole Bridges: A Strategy to Improve Energetics at the Molecular Level
Authors: Ma Jinchao , Chinnam Ajay Kumar , Cheng Guangbin , Yang Hongwei , Zhang Jiaheng , Shreeve Jean'ne M.
Published: December 2020

Many energetic materials synthesized to date have limited applications because of low thermal and/or mechanical stability. This limitation can be overcome by introducing structural modifications such as a bridging group. In this study, a series of 1,3,4‐oxadiazole‐bridged furazans was prepared. Their structures were confirmed by 1H and 13C NMR, infrared, elemental, and X‐ray crystallographic analyses. The thermal stability, friction sensitivity, impact sensitivity, detonation velocity, and detonation pressure were evaluated. The hydroxylammonium salt 8 has an excellent detonation performance (D=9101 m s−1, P=37.9 GPa) and insensitive properties (IS=17.4 J, FS=330 N), which show its great potential as a high‐performance insensitive explosive. Using quantum computation and crystal structure analysis, the effect of the introduction of the 1,3,4‐oxadiazole moiety on molecular reactivity and the difference between the sensitivities and thermal stabilities of mono‐ and bis‐1,3,4‐oxadiazole bridges are considered. The synthetic method for introducing 1,3,4‐oxadiazole and the systematic study of 1,3,4‐oxadiazole‐bridged compounds provide a theoretical basis for future energetics design.
A rapid, non‐destructive method for sampling castrating parasites in endangered bivalve molluscs
Authors: Brian Joshua I. , Aldridge David C.
Published: December 2020

Bivalves are important ecosystem engineers, and there is emerging evidence that many species are afflicted with castrating parasites. Understanding the prevalence of these largely overlooked parasites is crucial in understanding the fundamental biology of bivalves, informing conservation efforts, and providing a wider understanding of host–parasite dynamics.

Current techniques to assess the presence of parasites are destructive, making them untenable for endangered or protected populations. This article presents a non‐destructive method of sampling bivalve molluscs (Anodonta anatina) to detect castrating trematodes. Gonadal fluid is removed with a hypodermic needle from bivalves in situ and analysed in a laboratory setting without removing the mollusc from the field; this sampling mechanism has previously been shown not to harm the mollusc.

A single 50 μl sample is sufficient to detect both the presence and developmental stage of the trematode with greater than 95% reliability, with all but the lightest infections visible. We recommend that this technique should be used to enhance knowledge on host–parasite dynamics in bivalves, and inform sensible conservation for threatened species.