纳米酶

纳米酶(Nanozymes)是由我国科学家首次提出的新概念,它是一类具有生物催化功能的纳米材料,能够基于特定的纳米结构催化天然酶的底物并作为酶的代替品。自2007年首次报道以来,全球已有来自于55个国家的420多个研究机构证实了纳米酶的普遍规律。纳米酶的发现第一次揭示纳米材料蕴含一种独特的纳米效应——类酶催化效应。纳米酶作为一种新材料,既有纳米材料本身的理化性质,又有类似酶的催化功能,兼具天然酶与人工酶的优势于一身。其中,纳米结构不仅赋予纳米酶高效催化功能,而且使纳米酶比天然酶稳定,易于规模化生产。另外,纳米酶独特的多酶活性将为设计廉价、稳定、各种各样全新的催化级联反应提供功能分子。纳米酶是多学科交叉融合的典范,2022年被IUPAC评为十大化学新兴技术。在全球从事化学、酶学、材料学、生物学、医学、理论计算等多领域科学家的共同推进下,如今纳米酶已经成为新的研究热点。我国科学家在这一新兴领域一直发挥着引领作用,解析了纳米酶的构-效关系,将其催化活性提高了约1万倍,实现了超越天然酶的理性设计,创造了全球首个纳米酶产品,出版了纳米酶学英文专著,发布纳米酶术语及中国/国际标准化。更可喜的是,纳...     

一种新型微机电系统可调光衰减器

一种新型的低成本、小体积的电磁驱动微机电系统可调光衰减器,可用于密集波分复用系统中各信道的动态增益平衡。该器件采用电磁线圈驱动绕100微轴转动的微反射镜,运动部件行程极小。驱动电压为0～8V,工作范围0～35dB,动态响应时间小于2ms,插入损耗小于0．8dB,回波损耗小于-50．5dB。器件采用微细电火花加工技术制作,加工精度为微米量级。技术成熟,工艺简单,易于批量生产。采用有限元分析软件ANSYS对器件的结构建模,对电磁场及衰减曲线进行了理论分析,并与实测数据进行了比较,得出了相当满意的结果。     

一种MEMS可调光衰减器性能测试及动态响应分析

一种基于微细电火花加工(EDM)技术的非硅基MEMS可调光衰减器,以电磁线圈驱动微反射镜.本文介绍该器件特性测试及动态响应分析,结果表明,驱动电压为0～8 V,工作范围0～35 dB,动态响应时间为2 ms,插入损耗小于0.8 dB,回波损耗小于－50.5 dB.     

Study of low momentum track reconstruction for the BESⅢ main drift chamber

In order to overcome the difficulty brought by the circling charged tracks with transverse momentum less than 120 MeV in the BESⅢ Main Drift Chamber （MDC）, a specialized method called TCurlFinder was developed. This tracking method focuses on the charged track reconstruction under 120 MeV and possesses a special mechanism to reject background noise hits. The performance of the package has been carefully checked and tuned by both Monte Carlo data and real data. The study shows that this tracking method could obviously enhance the reconstruction efficiency in the low transverse momentum region, providing physics analysis with more and reliable data.     

Decay vertex reconstruction and 3-dimensional lifetime determination at BESⅢ

This paper focuses mainly on the vertex reconstruction of resonance particles with a relatively long lifetime such as Ks^0, A, as well as on lifetime measurements using a 3-dimensional fit. The kinematic constraints between the production and decay vertices and the decay vertex fitting algorithm based on the least squares method are both presented. Reconstruction efficiencies including experimental resolutions are discussed. The results and systematic errors are calculated based on a Monte Carlo simulation.     

Track reconstruction in the BESⅢ muon counter

The reconstruction algorithm for BESⅢ Muon Counter, MucRecAlg, is developed with the objectoriented language C＋＋ in BESⅢ offine software environment. MucRecAlg consists of the following functions：to find track seeds either from extrapolation of tracks in the main drift chamber or from the fired strips in muon counter, to select fired strips associated to the candidate tracks, to fit the candidate tracks with a linear or quadratic function and to calculate other parameters of the tracks for muon identification. Monte Carlo samples are generated to check the performance of the reconstruction package, such as reconstruction effciency, muon remaining rate and pion rejection rate, etc. The preliminary results show that the pion rejection rate is around 3%—4% while the muon remaining rate is better than 90% in 0.4—1.6 GeV/c momentum region, which meets the requirement as shown in the design report.     

非硅基底1×4微机电系统光开关

设计研制了一种小体积、低成本、可扩展的低电压非硅基底 1× 4微机电系统光开关。开关单元由电磁驱动 ,微反射镜绕直径 10 0 μm转轴转动 ,驱动电压为 5V ,开关时间小于 2ms,插入损耗小于 0 .84dB ,具有断电自锁功能。器件构造工艺采用微细电火花加工技术。用有限元法分析受力和磁场 ,进行结构优化设计 ,并着重介绍开关的实现及性能     

BESIII barrel time-of-flight （TOF） calibration using cosmic ray data

The principle of the method for the BESIII TOF calibration using cosmic ray data without magnetic field are reported in this paper. After applying calibration constants, the single-end readout time resolution could reach about 150 ps, and the time resolution for one layer is achieved to be about 110 ps. The paper also described the extraction scheme for the event start time of cosmic events.     

快速消解–原子荧光光谱法测定大米中总砷

建立快速消解–原子荧光光谱测定大米中砷含量的方法。以硫脲、抗坏血酸的质量浓度均为10 g/L的硫脲–抗坏血酸–盐酸溶液为掩蔽还原剂、10 g/L硼氢化钾溶液溶液为还原剂、盐酸溶液(5+95)为载流,在优化的仪器工作条件下,采用原子荧光光谱法测定,用标准曲线法定量。砷的质量浓度在0.00～10.00 g/L范围内与荧光强度具有良好的线性关系,相关系数为0.999 9,方法检出限为0.7 ng/g。用所建方法对大米样品进行测定,加标回收率为92.1%～104.9%,测定结果的相对标准偏差为0.27%～2.35%(n=5);对两种大米有证标准物质进行测定,测定值均在标准值不确定度范围内,相对误差分别为6.7%和8.3%。该方法精密度、准确度均满足分析要求。     

缪子物理实验现状及发展前景

寻找超出标准模型的新物理是当前粒子物理学最重要的任务之一.缪子物理实验,包括带电轻子味道破坏,缪子反常磁矩和电偶极矩,缪子素到反缪子素转换等是高强度前沿新物理研究的热点领域.文章介绍了国际上在这一领域开展实验的现状和展望,特别的,介绍了未来在中国开展相关实验的前景.