正电子冲击下氦电离三重微分截面的理论计算

我们发展了一种正电子碰撞原子电离的畸变波Born近似方法， 在这个方法中，正负电子偶素通道通过一个ab initio的光学势附加到入射粒子和靶的相互作用势上，且通道对电离作用被第一次被考虑在正电子碰撞原子电离的过程中. 应用这个方法计算了在50 eV入射能量范围氦的电离的三重微分截面，计算结果和实验数据很好的符合.     

High sensitivity conductivity-temperature-depth sensing based on an optical microfiber coupler combined fiber loop

In order to meet the practical needs of all-fiber conductivity-temperature-depth sensors with high sensitivity,compact structure,and easy packaging,this Letter uses a microfiber coupler combined with fiber loop(MCFL)reflective photonic device to conduct salinity,temperature,and deep sensing experiments.These MCFLs’dynamic range and resolution of salinity,temperature,and depth can meet the requirements of actual marine environment monitoring.This structure opens up a new design idea for the practical research of microfiber coupler-based marine environmental parameter sensors.     

The High Energy X-ray telescope (HE) onboard the Insight-HXMT astronomy satellite

The Insight-Hard X-ray Modulation Telescope(Insight-HXMT) is a broadband X-ray and γ-ray(1-3000 ke V) astronomy satellite. One of its three main telescopes is the High Energy X-ray telescope(HE). The main detector plane of HE comprises 18 Na I(Tl)/Cs I(Na) phoswich detectors, where Na I(Tl) is used as the primary detector to measure ~ 20-250 ke V photons incident from the field of view(FOV) defined by collimators, and Cs I(Na) is used as the active shielding detector to Na I(Tl) by pulse shape discrimination. Additionally, Cs I(Na) is used as an omnidirectional γ-ray monitor. The HE collimators have a diverse FOV,i.e. 1.1°×5.7°(15 units), 5.7°×5.7°(2 units), and blocked(1 unit). Therefore, the combined FOV of HE is approximately5.7°×5.7°. Each HE detector has a diameter of 190 mm resulting in a total geometrical area of approximately 5100 cm2, and the energy resolution is ~15% at 60 ke V. For each recorded X-ray event by HE, the timing accuracy is less than 10 μs and the deadtime is less than 10 μs. HE is used for observing spectra and temporal variability of X-ray sources in the 20-250 ke V band either by pointing observations for known sources or scanning observations to unveil new sources. Additionally, HE is used for monitoring the γ-ray burst in 0.2-3 Me V band. This paper not only presents the design and performance of HE instruments but also reports results of the on-ground calibration experiments.     

不同声音偏好的游客声景观主观评价差异——以丽江大研古镇为例*

古镇作为集自然景观与人文景观一体的景区，具有丰富的声音类型。本研究以大研古镇为例，通过实地调研探究不同声音偏好的游客对古镇声景观的主观评价差异。基于游客的声音偏好，将游客分为偏爱自然声和偏爱人工声两大类。通过因子分析提取游客声景观主观评价的5个主因子：大小、音质、效价、偏好和唤醒。进一步分析发现，这5个因子具有一定的层级性，其中从大小到唤醒代表声景观评价从声音的物理属性向声音的联想评价逐级提升。其中在低层级评价(大小、音质)中，偏好自然声的游客和偏好人工声的游客无显著差异，低层级评价具有稳定性；而在高层级评价(效价、偏好和唤醒)中，偏好人工声的游客更关注古镇声景观的淳朴性和遗产性。因此，游客对声景观的主观评价可视为一种指标，判断景区声景所处的评价阶段，从而为景区声景观改善提供更有针对性的建议。     

Melatonin stimulates aromatase expression and estradiol production in human granulosa-lutein cells: relevance for high serum estradiol levels in patients with ovarian hyperstimulation syndrome

Ovarian hyperstimulation syndrome (OHSS) is one of the most life-threatening and potentially fatal complications associated with controlled ovarian hyperstimulation (COH) during in vitro fertilization (IVF) treatment. Although the pathogenesis of OHSS remains unclear, elevated serum estradiol (E2) levels before human chorionic gonadotropin (hCG) administration are associated with the risk of OHSS. The pineal hormone melatonin and its receptors are expressed in human granulosa cells and have been shown to stimulate E2 production. However, the effect of melatonin on the expression of aromatase, an enzyme responsible for a key step in the biosynthesis of E2, in human granulosa cells remains to be determined. Here, we demonstrate that melatonin upregulates aromatase expression in primary cultured human granulosa-lutein (hGL) cells through the melatonin receptor-mediated PKA-CREB pathway. Using a mouse model of OHSS, we demonstrate that administration of the melatonin receptor inhibitor luzindole inhibits the development of OHSS. In addition, the expression of ovarian aromatase and serum E2 levels are upregulated in OHSS mice compared to control mice, but this upregulation is attenuated by inhibition of the function of melatonin. Moreover, clinical results reveal that aromatase expression levels are upregulated in hGL cells from OHSS patients. Melatonin and E2 levels in the follicular fluid are significantly higher in OHSS patients than in non-OHSS patients. Furthermore, melatonin levels are positively correlated with E2 levels in follicular fluid. This study helps to elucidate the mechanisms mediating the expression of aromatase in hGL cells and provides a potential mechanism explaining the high E2 levels in patients with OHSS.Subject terms: Endocrine reproductive disorders, Endocrine reproductive disorders     

Al2O3衬底无催化剂生长GaN纳米线及其光学性能

采用一种绿色的等离子增强化学气相沉积法,以Al2O3为衬底, Ga金属为镓源, N2为氮源,在不采用催化剂的情况下,成功制备获得了结晶质量良好的GaN纳米线.研究表明,生长温度可显著调控GaN纳米线的形貌,当反应温度为950℃时,生长出的GaN微米片为六边形;当反应温度为1000℃时,生长出了长度为10-20μm的超长GaN纳米线.随着反应时间增加, GaN纳米线的长度增加. GaN纳米线内部存在着压应力,应力大小为0.84 GPa.同时,也进一步讨论了GaN纳米线无催化剂生长机制. GaN纳米线光致发光结果显示, GaN纳米线缺陷较少,结晶质量良好,在360 nm处有一个较为尖锐的本征发光峰,可应用于紫外激光器等光电子器件.本研究结果将为新型光电器件低成本绿色制备提供一个可行的技术方案.     

Feature extraction method based on NOFRFs and its application in faulty rotor system with slight misalignment

Nonlinear Dynamics - Fault features extraction method for slight misalignment of rotor systems is researched in this paper. When a rotor system with faults is excited by harmonic inputs, system...     

Review of highly charged ion production with ECR ion source and the future opportunities for HCI physics

In recent years, there is very intense worldwide research and development work on electron cyclotron resonance ion source (ECRIS). Remarkable progress represented by the third generation superconducting ECRIS has been made with regards of intense highly charged ion beam production such as >600 eμA Ar¹⁶⁺, >10 eμA Ar¹⁸⁺, and hundreds of enA He-like Kr³⁴⁺. A low energy heavy ion platform named Low Energy heavy ion Accelerator Facility (LEAF) that features a next generation 45 GHz ECRIS, a 300 kV high voltage platform, a 0.5 MeV/u radio-frequency quadrupole, and several multidisciplinary experimental terminals is under construction at the Institute of Modern Physics (IMP). This paper will report on the recent progress with ECRIS dedicated to highly charged ions and the status of LEAF at IMP that will provide new opportunities for highly charged ion physics in the near future.     

Fractional damping enhances chaos in the nonlinear Helmholtz oscillator

Nonlinear Dynamics - The main purpose of this paper is to study both the underdamped and the overdamped dynamics of the nonlinear Helmholtz oscillator with a fractional-order damping. For that...     

Paraxial propagation of cosh-Airy vortex beams in chiral medium

Propagation dynamics of the cosh-Airy vortex(CAiV) beams in a chiral medium is investigated analytically with Huygens–Fresnel diffraction integral formula. The results show that the CAiV beams are split into the left circularly polarized vortex(LCPV) beams and the right circularly polarized vortex(RCPV) beams with different propagation trajectories in the chiral medium. We mainly investigate the effect of the cosh parameter on the propagation process of the CAiV beams.The propagation characteristics, including intensity distribution, propagation trajectory, peak intensity, main lobe's intensity, Poynting vector, and angular momentum are discussed in detail. We find that the cosh parameter affects the intensity distribution of the CAiV beams but not its propagation trajectory. As the cosh parameter increases, the distribution areas of the LCPV and RCPV beams become wider, and the side lobe's intensity and peak intensity become larger. Besides, the main lobe's intensity of the LCPV and RCPV beams increase with the increase of the cosh parameter at a farther propagation distance, which is confirmed by the variation trend of the Poynting vector. It is significant that we can vary the cosh parameter to control the intensity distribution, main lobe's intensity, and peak intensity of the CAiV beams without changing the propagation trajectory. Our results may provide some support for applications of the CAiV beams in optical micromanipulation.