Ethernet-APL推动流程工业现场网络的升级

Ethernet-APL改变了之前现场级网络连接的固有规定,尤其适用于流程工业。它采用单一协议实现端到端联网,可在长达1000 m的电缆长度线路上实现高速传输,同时也具备本质安全性,适用于潜在爆炸区域。

KAGRA引力波探测器中频率相关压缩态实验进展

随着技术的发展,下一代引力波探测器的激光功率将得到进一步提高。大光斑半径的应用也将使探测器的热噪声进一步降低,因此,量子噪声将成为在全频段限制引力波探测器灵敏度的首要因素。作为目前最有保障的一种降低量子噪声的技术,频率相关压缩态很可能将被应用于下一代所有引力波探测器中^([1])。频率相关压缩态可以通过将频率不相关压缩态与滤波腔相结合而产生。基于滤波腔具有的频率响应特性,这一技术的应用可以使低频波段的辐射压噪声有效降低,同时实现高频波段散粒噪声的降低,从而实现全探测频段灵敏度的提升。基于日本KAGRA引力波探测器的设计,我们预计将9dB压缩度的压缩态与周损失为8×10^(-5)的300m滤波腔相结合,可以使探测器灵敏度在全探测频段提高1倍。此实验于2015年开始,目前滤波腔的安装调试已经基本完成,得到的结果基本与实验前的模拟相符合。与频率不相关压缩态光学实验台的安装过程也已经过半,通过温度和控制回路的调制,二次谐波腔的转化率已经超过50%。

Numerical and Experimental Modelling of Gas Flow and Heat Transfer in the Air Gap of an Electric Machine. Part II: Grooved Surfaces

The study deals with the cooling of a high-speed electric machine through an air gap with numerical and experimental methods. The rotation speed of the test machine is between 5000-4000 r/rain and the machine is cooled by a forced gas flow through the air gap. In the previous part of the research the friction coefficient was measured for smooth and grooved stator cases with a smooth rotor. The heat transfer coefficient was recently calculated by a numerical method and measured for a smooth stator-rotor combination. In this report the cases with axial groove slots at the stator and/or rotor surfaces are studied. Numerical flow simulations and measurements have been done for the test machine dimensions at a large velocity range. At constant mass flow rate the heat transfer coefficients by the numerical method attain bigger values with groove slots on the stator or rotor surfaces. The results by the numerical method have been confirmed with measurements. The RdF-sensor was glued to the stator and rotor surfaces to measure the heat flux through the surface, as well as the temperature.

Simulation of beam size multiknobs correction at the Accelerator Test Facility 2 at KEK

The ATF2 project is the final focus system prototype for the ILC and CLIC linear collider projects, with a purpose of reaching a 37 nm vertical beam size at the interaction point （IP）. During the initial commissioning, we started with larger-than-nominal β-functions at the IP in order to reduce the effects from higher-order optical aberrations and thereby simplifying the optical corrections needed. We report on the simulation studies at two different IP locations developed based on waist scan, dispersion, coupling and β function multiknobs correction in the large β optics of ATF2, in the presence of two kinds of magnet inaccuracies （quadrupole gradient and roll errors） to generate all possible linear optic distortions at the IP. A vertical beam size which is very close to the nominal beam size is obtained based on the simulation study.

Study of the CKM angleγsensitivity using flavor untagged B_(s)^(0)→D^(+)^(0)Ф decays

A sensitivity study on the measurement of the CKM angle γ from B_(s)^(0)→D^(+)^(0)Ф decays is conducted us-ing the D-meson reconstructed in the quasi flavour-specific modes Kπ,K3π,and Kππ^(0),as well as CP-eigenstate modes KK and m,where the notation DO corresponds toa D0 or D0 meson.The LHCb experiment is presented as a use case.A statistical uncertainty of approximately 8°-19°can be achieved with the pp collision data collcted in the LHCb experiment from 2011 to 2018.The sensitivity to r should be of the order 3°-8°after accumulating 23 fb^(-1) of pp collision data by 2025,whereas it is expected to improve further by 300 fb^(-1) by the second half of the 2030 decade.The accuracy is dependent on the strong parameters r and og,which together with ydescribe the interfer-ence between the leading ampliudes of the B_(s)^(0)→D^(+)^(0)Ф decays.

Study of the production of Λ_b^0 band ~0 hadrons in pp collisions and first measurement of the Λ_b^0→J/ψpK^- branching fraction

The product of the ∧0/b （-B/0） differential production cross-section and the branching fraction of the decay ∧0/b→ J/ψ pK-（-B/0→ J/ψ-K＊（892）0）is measured as a function of the beauty hadron transverse momentum, PT, and rapidity, y. The kinematic region of the measurements is pT〈20 GeV/c and 2.0 〈g〈4.5.The measurements use a data sample corresponding to an integrated luminosity of 3fb-1 collected by the LHCb detector in pp collisions at centre-of-mass energies √s=7 TeV in 2011 and √s=8 TeV in 2012. Based on previous LHCb results of the fragmentation fraction ratio,f∧0/b/fd,the branching fraction of the decay ∧0/b→ J/ψ pK-is measured to be B（∧0/b→ J/ψ pK-）=（3.17±0.04±0.07±0.34＋0.45/-0.28）×10-4,where the first uncertainty is statistical, the second is systematic, the third is due to the uncertainty on the branching fraction of the decay -B/0 →J/ψ-K＊（892）0,and the fourth is due to the knowledge of f∧0/b/fd.The sum of the asymmetries in the production and decay between ∧0/b and ∧0/bis also measured as a function of PT and y.The previously published branching fraction of ∧0/b→ J/ψ pπ-,relative to that of ∧0/b→ J/ψ pK-,is updated. The branching fractions of ∧0/b→P＋c（→ J/ψp）K-are determined.