Afterpulse measurement of JUNO 20‑inch PMTs

In this study,we present the large photomultiplier tube(PMT)afterpulse measurement results obtained from the Jiangmen underground neutrino observatory(JUNO)experiment.A total of 11 dynode-PMTs(R12860)from the Hamamatsu company(Hamamatsu Photonics K.K.(HPK))and 150 micro-channel plate PMTs(MCP-PMTs,GDB-6201)from the NNVT company(North Night Vision Technology Co.,Ltd.(NNVT))were tested.Subsequently,an afterpulse model was built according to the afterpulse time distribution and the probability of occurrence for these two types of PMTs.The average ratio of the total afterpulse charge with a delay between 0.5μs and 20μs to the primary pulse charge is∼5.7%(13.2%)for the tested MCPPMTs(dynode-PMTs).The JUNO experiment will deploy 20,01220-inch PMTs;this study will benefit detector simulation,event reconstruction,and data analysis regarding the JUNO experiment.

精密多目标跟踪系统(PMTS)

微波辐射源的无源测向和跟踪是防空传感器和火控系统中越来越重要的一个特点。在存在低仰角多径效应的情况下,需要极高的截获概率以及极好的仰角与方位测向精度,这就要求采用高性能的测向技术。本文叙述阿纳伦公司的研制型7.5～18GHz精密多目标跟踪系统(PMTS),并给出在水面上对地面目标和机载目标进行现场试验的结果,表明在生产中可以使方位与仰角精度优于0.

Thermal management for the underwater frontend and readout electronics of JUNO 20‑inch PMTs

Background The Jiangmen underground neutrino observatory(JUNO)is a new generation of long-term operation neutrino experimental platform under construction in Jiangmen,Guangdong province of southern China.The underwater frontend and readout electronics(F&R electronics)are placed nearby the 20-inch PMTs and readout current signals from three PMTs.The electronics are sealed in a stainless-steel underwater box to keep them dry,and temperature control of the electronics plays a significant role in their reliability.Methods A conductive cooling structure based on the passive cooling method is designed for the 20-inch PMT F&R electronics.Both numerical simulation and experimental tests were performed to evaluate the cooling structures'thermal performance.Results The results show that the case temperature of the respective chip for 20-inch PMT F&R electronics is less than 30℃in ambient still water.Conclusion The case temperature of the respective chip meets the strict temperature requirement for the F&R electronics.The JUNO collaboration has adopted this cooling structure for the 20-inch PMT readout electronics.

跨层次视角下信息安全氛围对员工信息安全制度遵守意愿的影响作用

员工安全遵守行为已成为保护企业信息资产安全的重要保障。侧重人因因素,讨论如何通过有效方法来规范和引导员工遵守信息安全制度。基于保护动机理论(protection motivation theory,PMT)和社会认知理论,采用跨层次分析方法,以员工信息安全制度遵守意愿为因变量,信息安全氛围为组织层面变量,感知严重性、感知易感性、反应效能和自我效能为个体层面变量构建研究模型。借鉴成熟量表设计问卷,发放问卷并获取有效数据,应用SPSS 26.0软件对研究模型进行假设验证。实证结果表明:感知严重性、感知易感性、反应效能和自我效能均正向影响员工信息安全制度遵守意愿;信息安全氛围跨层次既能直接影响员工信息安全制度遵守意愿,又可通过个体层面变量对结果变量产生影响作用。为强化企业安全管理提供一定的理论支撑。

FAST所受PMT基站电磁干扰及用频防护方法综述

为确定500 m口径球面射电望远镜(Five-hundred-meter Aperture Spherical radio Telescope,FAST)与其周边公众移动通信(Public Mobile Telecommunications,PMT)系统的电磁兼容(electromagnetic compatibility,EMC)特性,本文综合论述了FAST宁静区内中国移动、中国联通和中国电信三大运营商所属PMT基站对其产生的电磁干扰。首先,从射电天文业务的频谱划分谈起,论述了射电天文业务干扰源类型,引出了其运行保护标准,进而针对FAST详细说明了FAST宁静区的用频法规和保护要求;其次,分析了ITU-R建议电波传播预测与干扰分析方法,并通过实地测量验证了该方法的适用性,进一步针对性地分析了PMT基站的电磁辐射传播特性,综合评估了FAST宁静区内PMT基站的干扰情况:FAST宁静区域90.24%的PMT基站在一定程度上均会对FAST产生干扰,而在所选分析条件下,仅有43.14%的数据符合FAST保护要求;最后,针对PMT基站干扰信号的抑制和消除,分析了常用的射电天文射频干扰抑制方法,同时为保障FAST免受PMT基站干扰,从FAST和PMT基站的角度出发论述了可行的用频防护措施,并基于实施难度、经济成本、策略收益和通信质量4类指标建立了防护方法的评估体系,对所提防护方法进行了实例说明。上述研究成果可为保障FAST的安全观测提供技术基础。

IPD落地关键要素——以团队构建为例

IPD(集成产品开发)是一套面向市场、高效协同的全新产品开发模式、理念与方法,其有效性已经得到众多企业的一致认可。新质生产力倡导以科技创新为主导,IPD是帮助企业锻造新质生产力的利器。中国已经有数百家企业进行了IPD导入,本文从团队构建角度分析IPD落地的关键要素。

Study on relative collection efficiency of PMTs with spotlight

nd Photon detection efficiency is a key parameter of PMTs in high-precision neutrino and dark matter experiments,while normally the quantum efficiency is used with a normalization factor and angular response as the detection efficiency,where it is always coupled with detector response from the calibration normalization.Here,the absolute photon detection efficiency of 20′′PMTs in photon-counting level is further considered rather than the combination of quantum efficiency and normalization factors.Purpose and method In order to have a good understanding of photon detection efficiency of the large-area PMT,we conduct a detailed comparison of relative collection efficiencies of a series of PMTs with spotlight.This study is based on the tests of relative quantum efficiency and relative detection efficiency,checked with several light intensities.Conclusion All the results are consistent in relative QE and DE measurement with different light intensities,and the error of each parameter is coupled in our studies.Based on the measurements,Hamamatsu R12860 shows the maximum collection efficiency with spotlight at PMT center,and Hamamatsu R12199,R1355 and HZC XP72B22 have the same level of CE within the uncertainty.Discussion Following the configuration on incident light and DE definition,we can further define the DE of a large-area PMT with similar algorithms,which will also be used for detector simulation in JUNO.

Study of the front-end signal for the 3-inch PMTs instrumentation in JUNO

A total of 25,6003-inch PMTs will be installed in Jiangmen Underground Neutrino Observatory(JUNO)to achieve more precise energy calibration and to extend the physics detection potential.Performances of all bare PMTs have been characterized and these PMTs are being instrumented with the high voltage divider,underwater front-end cable,and connector.In this paper,we present a dedicated study on signal quality at different stages of the instrumentation.An optimized high voltage ratio was confirmed andfinalized which improved the PMT transit time spread by 25%.The signal charge was attenuated by 22.5%(13.0%)in the 10 m(5 m)cable and it required the addition of 45 V(23 V)to compensate for the loss of PMT gain.There was a 1%overshoot following the PMT signal and no sign of reflection in the connector.A group of 163-inch PMTs with the full instrumentation was installed in the JUNO prototype detector together with a few 8-inch and 20-inch PMTs,which showed good stability and demonstrated a photon detection system with multiple types of PMTs.

Performance of compact plastic scintillator strips with wavelength shifting fibers using a photomultiplier tube or silicon photomultiplier readout

This study presents the design and performance results for compact plastic scintillator strips using a wavelength shifting fiber(WLS-fiber)readout with dimensions of 0.1 m×0.02 m×2 m.This approach was evaluated as a candidate for a cosmic-ray muon detector for the Taishan Antineutrino Observatory(JUNO-TAO).The strips coupled with 3-inch photomultiplier tubes(PMTs)were measured and compared between the single-end and double-end readout options.Additionally,a strip using the double-end option coupling with a silicon photomultiplier(SiPM)was further evaluated and compared with the results obtained using PMTs.The performance of the strips was determined by a detailed survey along their length with a cosmicray muon after detailed characterization of the 3-inch PMTs and SiPMs.The proposed design employing a compact plastic scintillator strip with WLS-fiber coupling to a SiPM provides a good choice for cosmic-ray muon veto detectors,particularly when detector dimensions must be limited.

Effect of soaking time of dithionite-citrate-bicarbonate solution on strength and deformation characteristics of lateritic soil

This study aimed to reveal the influence of different free-iron-oxides contents on the strength and deformation characteristics of in situ lateritic soil.A test method that combined the selective chemical dissolution method and in situ Ménard pressuremeter test(PMT)was proposed.The soaking time in dithioniteecitrateebicarbonate(DCB)solution was used as a variable to control the free-iron-oxides content in lateritic soil.Then,the in situ lateritic soil boreholes with different soaking time were tested by PMT.The results showed that the in situ horizontal pressure p0,critical edge pressure pf,ultimate pressure prediction pl,pressuremeter modulus Em,shear modulus Gm,and foundation-bearing capacity f0k of lateritic soil decreased rapidly after immersing in DCB solution within 1e4 d.With increasing soaking time,the decrease rate reduced gradually.Moreover,the relationship curve between free-iron-oxides content and soaking time declined rapidly and then stabilized,and the free-iron-oxides content at the inflection point was 30.11 g/kg.When the free-iron-oxides content changed to the inflection point,the free-iron-oxides that played a cementing role was largely removed,indicating that the effective cementing iron-content of Miaoling lateritic soil was about 52.9%.This study demonstrated that the proposed test method can determine the influence of free-iron-oxides content on the strength and deformation characteristics of lateritic soil.

核测井仪探测器输出信号特征分析及信号处理电路设计

伽马探测器是核测井仪的核心器件,起到将地层放射性物理信息转化为可量化的电信号的作用,是实现数字化测井的桥梁。其输出信号是微弱的负极性电流脉冲,不能直接被信号采集电路所接收,因此,需要设计专门的信号处理电路进行规范化调整。对伽马探测器输出信号进行特征分析并结合煤矿应用环境特点,设计并实现了可满足小体积、低功耗、高可靠性需求的信号处理电路。经测试验证表明,电路性能稳定,能有效将待处理的非标信号调整得到标准的方波信号,达到预期技术需求。

基于温度资料估算参考作物腾发量的方法比较

以Penman-Monteith方法计算的参考作物腾发量ETo为标准,与采用温度法和辐射法的Penman-Monteith温度法(PMT)、修正的PMT(PMT-cor)、Hargreaves-Samain(HG)、修正的HG公式(HG-M1,HG-M2)、Thornthwaite公式、Irmak公式、修正的Irmak公式(Irmak-cor)、Mc Guinness Bordne公式(M-B)的估算值进行对比分析,同时引入干旱指数对温度法中的PMT公式进行修正,采用多元线性拟合对辐射法中的Irmak公式进行修正。结果表明:温度法中的PMT公式、PMT-cor公式、HG公式和辐射法中Irmak公式、Irmak-cor公式的计算值与PM法计算值间的回归系数b都接近于1.0,相关系数R2大于0.80,相对误差RE小于20%,一致性指数d大于0.95。通过交叉比较发现,Irmak-cor公式精度较高(b=1.00、R2=0.98、RMSE=0.17 mm/d、RE=7%、d=1.00),其次是Irmak公式(b=1.03、R2=0.95、RMSE=0.31 mm/d、RE=12%、d=0.99),再次是PMT、PMT-cor、HG方法。考虑计算结果的精确度,该地区首选Irmak-cor公式估算ETo;如果考虑计算简便,该地区可选HG公式估算ETo。

中国沿海海表温度均一性检验和订正

利用惩罚最大T检验(Penalized Maximal T test,PMT)方法,选取均一的邻近气象站为参考站,基于月平均地面气温(SAT)资料,利用相关系数权重平均方法构建参考序列,同时结合元数据信息,对1960-2011年中国沿海27个海洋观测站月平均海表温度(SST)进行了均一性检验与订正,并分析了造成海表温度序列非均一的主要原因。结果表明,中国沿海海洋台站海表温度资料存在较为严重的非均一性问题,几乎所有的台站都存在断点,仪器变更(包括人工观测转自动观测)(占总断点数的52.4%)和迁站(占总断点数的33.3%)是造成序列非均一的主要原因。整套资料负订正量所占比例较高,这种负订正量与人工转自动观测后海表温度观测值偏低有密切关系。这也使得订正后中国沿海平均海表温度趋势与订正前存在明显差异,订正后中国沿海海表温度呈明显的加速上升趋势。

环渤海沿岸海表温度资料的均一性检验与订正

本文对环渤海沿岸具有代表性且资料完整的6个海洋观测站的月均海表温度(SST)序列作均一性检验和订正。我国海洋观测站密集度低,难以选择参考序列,本文首先采用不依赖参考序列的惩罚最大F检验(PMFT)方法对SST序列检验,利用详尽的元数据对检验结果进行确认,再对不连续点订正,该方法适用于元数据详尽的海洋观测站。对于元数据不详尽的观测站,使用惩罚最大T检验(PMT)方法,选取与海洋台站距离近且相关显著的气象观测站的均一化地面气温序列来制作参考序列,对SST序列进行检验和订正。结果表明,环渤海地区SST序列都存在一定非均一性,观测站较大距离迁移和观测系统变更(从人工观测到自动化观测)是造成非均一性的重要原因。订正后的环渤海地区年平均SST增温趋势更加明显。本文使用不同方法来检验SST序列的均一性,该思路对沿海其他海区观测站SST均一性检验和订正有一定参考价值和应用前景,可为沿海气候变化研究提供科学准确的第一手资料。

东北地区月气温序列的均一性检验和订正

本文采用惩罚最大T检验(PMT)方法,结合台站历史沿革信息,对东北地区129个气象站月最高气温和最低气温资料进行均一性检验和订正,并与已有均一化数据集(CHHT)进行对比分析。结果表明:气温的非均一性在空间上普遍存在,最高温和最低温分别检测出断点74个和94个,资料拼接和迁站是造成非均一性的重要因素。均一性检验和订正提高了东北地区最高气温和最低气温的空间一致性,线性趋势空间分布更加合理,订正之后变化趋势略有增加,年平均最高气温和最低气温分别由0.1和0.22℃·(10 a)^(-1)增至0.17和0.33℃·(10a)^(-1),与CHHT相比,两套数据时间相关系数在0.9以上,对东北地区气候长期演变趋势基本一致,东北地区年平均最高气温和最低气温均呈显著升温趋势,采用PMT得到的年平均最高气温和最低气温变化趋势较CHHT分别偏高0.05和0.03℃·(10 a)^(-1),在线性趋势空间分布上PMT均一化检验订正结果较CHHT略有改善。

重组产毒多杀性巴氏杆菌毒素PMT的N-端和C-端蛋白的生物学活性及免疫原性

将5个toxA基因片段N1518、C2345、N3172、N3388和C2115分别克隆到合适的原核表达载体pET-28a(b,c)系统,其中pET28a-N1518和pET28b-C2115在大肠杆菌成功表达,获得大小分别为57kDa和78kDa的融合蛋白rPMT-N和rPMT-C,Western blot检测证实两种表达产物均具有反应原性。分别以200μg rPMT-N和rPMT-C对小白鼠进行体内生物学活性试验,结果两种表达蛋白均不能致死小白鼠;体外细胞毒性试验证实896ng/mL的rPMT-N能使Vero细胞发生病变,而rPMT-C对Vero细胞无明显毒性作用。将rPMT-N和rPMT-C制成亚单位疫苗,同时设天然PMT及无菌PBS对照组,间隔2周分2次皮下免疫小白鼠。二免后2周用8.2×10~5 CFU的HN-13株T^+Pm进行腹腔攻毒,结果rPMT-N组保护率为90.0%(9/10),rPMT-C组保护率为50.0%(5/10),天然PMT组保护率为80.0%(8/10)。综上试验表明,rPMT-N具有良好的生物学活性和免疫原性,可作为PAR疫苗添加成分,显示了良好的应用前景。

微秒级激光荧光寿命测量

本文描述了由氮分子激光器，小型光栅单色器，光电倍增管（ＰＭＴ），记忆示波器等组装成的激光荧光寿命测量装置。讨论了该装置的测量原理和方法，并测定了ＹＡＧ晶体，钒磷酸盐等样品的荧光寿命，测定的结果与标准样品值相符。

基于保护动机理论的健康APP用户使用研究

移动医疗发展迅速,医疗健康管理成为研究热点,为了研究用户对健康APP的采纳意愿及影响因素。本文从技术视角和健康行为改变视角,基于UTAUT理论和PMT理论构建用户使用意愿研究模型,通过调查问卷收集数据,并利用SPSS和AMOS进行统计分析和结构方程建模。研究发现:绩效期望、信任感知、社会影响和努力期望依次显著正向影响用户的使用意愿;信任感知正向影响用户的自我效能和反应效能;用户的自我效能和反应效能分别正向影响用户的绩效期望、努力期望和社会影响;并为医疗健康服务商及APP开发运维商提供建议。

共聚焦生物芯片扫描仪中PMT电流增益的自动控制

根据共聚焦生物芯片扫描仪获得的图像 ,设计了计算机控制下的PMT电流增益自动控制系统 根据计算生物芯片图像的灰度分布与期望灰度分布的差异 ,得到期望灰度分布时PMT的期望电流增益 ,进而获得PMT的期望控制电压 一个 1 2位数模转换器产生期望控制电压 ,自动控制PMT电流增益的调节 ,控制电压精度高达 2mV 实验结果表明 ,所设计的PMT电流增益自动控制系统可快速、准确地实现PMT电流增益调节 ,并具有稳定性高。

基于新一代Argos卫星系统的表面漂流浮标设计

介绍了改进的表面漂流浮标的功能、组成和设计过程。该浮标加装了Argos卫星收发器和GPS模块,相比目前的表面漂流浮标,该浮标具有数据传输有效性高,功耗低,采集数据量大,可双向通信等特点。浮标在布放后可通过网络申请对浮标参数进行设置,再由卫星将设置参数发送给浮标;浮标利用GPS模块对其直接定位,且定位精度显著提高。浮标测量的数据可服务于水产养殖、环境保护和生态治理、气象和海洋监测预报、军事监测等多个领域。