Numerical Simulation of Solitary Wave Forces on A Vertical Cylinder on A Slope Beach

Wave forces acting on a vertical cylinder at different locations on a slope beach in the near-shore region are investigated considering solitary waves as incoming waves. Based on the Reynolds-averaged Navier-Stokes equations and the k-epsilon turbulence model, wave forces due to the interaction between the solitary wave and cylinder are simulated and analyzed with different incident wave heights and cylinder locations. The numerical results are first compared with previous theoretical and experimental results to validate the model accuracy. Then, the wave forces and characteristics around the cylinder are studied, including the velocity field, wave surface elevation and pressure. The effects of relative wave height, Keulegan-Carpenter (KC) number and cylinder locations on the wave forces are also discussed. The results show that the wave forces exerted on a cylinder exponentially increase with the increasing incident wave height and KC number. Before the wave force peaks, the growth rate of the wave force shows an increasing trend as the cylinder moves onshore. The cylinder location has a notable effect on the wave force on the cylinder in the near-shore region. As the cylinder moves onshore, the wave force on the cylinder initially increases and then decreases. For the cases considered here, the maximum wave force appears when the cylinder is located one cylinder diameter below the still-water shoreline. Furthermore, the fluid velocity peaks when the maximum wave force appears at the same location

RAPD分析野生和养殖太湖秀丽白虾的遗传多样性

<正>秀丽白虾(Exopalaemon modestus)广泛分布于我国淡水湖泊及河流中,南北均产。在太湖的虾类组成中,秀丽白虾占50%以上。近年来,由于水质污染和过度捕捞等原因,太湖秀丽白虾的繁衍、生存受到了很大威胁,白虾种质资源保护

RETGEM探测器的初步测试

研制了一种新型的带有阻抗性电极的TGEM——RETGEM(Thick GEM with Resistive Electrodes)探测器,阻抗性电极可以有效地保护探测器和前端电子学免于偶尔放电的损伤。对RETGEM探测器进行了初步测试,其中包括计数率、能量分辨、增益以及打火率。结果表明,探测器达到了设计的基本要求

13单元望远镜探测器阵列用于轻粒子小角关联测量

由穿透型Ｓｉ探测器和ＢＧＯ晶体组成的ΔＥ－Ｅ望远镜已用来探测由每核子２５ＭｅＶ的Ａｒ引起的反应中发射的轻带电粒子。用ΔＥ－Ｅ方法来鉴别反应产物。研究了ＢＧＯ晶体对各种较轻粒子的响应。一密度六角排列的１３单元ΔＥ－Ｅ（Ｓｉ－ＢＧＯ）望远镜阵列已用来测量中能重离子诱发的相干涉的轻带电粒子

Phoswich探测器的重离子束测试

利用一套由１ｍｍ厚的ＰＩＬＯＴ－Ｕ和４０ｍｍ厚的ＮＥ１１５塑料闪烁体组成的Ｐｈｏｓｗｉｃｈ（光叠层望远镜）探测器测量了４０Ａｒ（２５ＭｅＶ／ｕ）＋１９７Ａｕ反应中出射的产物，粒子鉴别采用Ｐｈｏｓｗｉｃｈ的快慢成分方法．结果表明该方法能清楚地分辨出粒子的电荷．对Ｚ＝１的粒子，ｐ、ｄ和ｔ亦能分开．A Phoswich detector consisting of a 1mm thick PILOT-U and a 40mm thick NE115 is used to measure the particles emitted in 4oAr+ 197Au reaction with beam energy of 25 MeV/u. By measuring the fast and slow composition of the Phoswich aclear Z identification is obtained. For Z= 1 particles, p,d and t can be separated.国家自然科学基金,中国科学院留学经费择优支持基

中能区~（40）Ar＋~（197）Au反应中轻粒子的发射时间测量

本文报道了２５ＭｅＶ／ｕ４０Ａｒ＋１９７Ａｕ反应中粒子－粒子关联函数的实验结果．利用三体弹道模型从关联函数提取了轻粒子发射时间．轻粒子的平均发射时间随粒子能量而变化，从低能时的约３００ｆｍ／ｃ下降至高能时的约１００ｆｍ／ｃ．Particle-particle correlation functions have been measured for 40Ar+197Au collisions at E=25 MeV/u.Emission time of light particles has been extracted from correlation functions using the three-body trajectory model.The average emission time varies with the energy of particles. It decreases from about 300 fm/c for low energy particles to about 100fm/c for energetic particles.国家自然科学基金,中国科学院留学经费择优支持基

高位置分辨平行板雪崩室的研制

描述了灵敏面积为 10 0 mm× 10 0 mm和 150 mm× 150 mm两维位置灵敏雪崩室。采用分块结构 ,电极从两端分前后点引出 ,增加了延迟线的长度 ,延迟线跨边连接和在大气中直接封真空技术。在流动的 4 2 0 Pa的正庚烷气体中 ,用2 52 Cf裂变源对探测器的性能进行了测试 ,得到Δx=Δy=1mm的位置分辨

Amplitude analysis of the decays D0 → π+π−π+π− and D0 → π+π−π0π0*

Using e+e− annihilation data corresponding to an integrated luminosity of 2.93 fb−1 taken at the center-of-mass energy √s = 3.773 GeV with the BESIII detector, a joint amplitude analysis is performed on the decays D0 → π+π−π+π− and D0 → π+π−π0π0 (non-η). The fit fractions of individual components are obtained, and large interferences among the dominant components of the decays D0 → a1(1260)π, D0 → π(1300)π, D0 → ρ(770)ρ(770), and D0 → 2(ππ)S are observed in both channels. With the obtained amplitude model, the CP-even fractions of D0 → π+π−π+π− and D0 → π+π−π0π0 (non-η) are determined to be (75.2 ± 1.1stat. ± 1.5syst.) % and (68.9 ± 1.5stat. ± 2.4syst.)%, respectively. The branching fractions of D0 → π+π−π+π− and D0 → π+π−π0π0 (non-η) are measured to be (0.688 ± 0.010stat. ± 0.010syst.)% and (0.951 ± 0.025stat. ± 0.021syst.)%, respectively. The amplitude analysis provides an important model for the binning strategy in measuring the strong phase parameters of D0 → 4π when used to determine the CKM angle γ(φ3) via the B− → DK− decay

Measurement of integrated luminosity of data collected at 3.773 GeV by BESIII from 2021 to 2024

We present a measurement of the integrated luminosity e+e- of collision data collected by the BESIII detector at the BEPCII collider at a center-of-mass energy of Ecm = 3.773 GeV. The integrated luminosities of the datasets taken from December 2021 to June 2022, from November 2022 to June 2023, and from October 2023 to February 2024 were determined to be 4.995±0.019 fb-1, 8.157±0.031 fb-1, and 4.191±0.016 fb-1, respectively, by analyzing large angle Bhabha scattering events. The uncertainties are dominated by systematic effects, and the statistical uncertainties are negligible. Our results provide essential input for future analyses and precision measurements