Investigation of the properties of the flux and interaction of ultrahigh-energy cosmic rays by the method of local-muon-density spectra

A new method for studying extensive air showers is considered. The method is based on the phenomenology of the localmuon density. It is shown that measurement ofmuon-density spectra at various zenith angles makes it possible to obtain information about the energy spectrum, mass composition, and interaction of cosmic rays over a broad range of energies (10¹⁵–10¹⁸ eV) by using a single array of comparatively small size. The results obtained from a comparison of experimental data on muon bundles from the DECOR coordinate detector with the results of simulation performed under various assumptions on the properties of the primary flux and for various hadron-interaction models are presented, and possible versions of the interpretation of these results are discussed.     

The Muon Puzzle in High-Energy Air Showers

The Muon Puzzle is a long-standing issue in the observation of high-energy cosmic rays. In 2018, eight leading air shower experiments combined their data on muons in high-energy air showers and established the existence of an energy-dependent offset with a significance of 8σ. The muon abundance is an important indicator for the cosmic ray mass. The Muon Puzzle needs to be solved to infer the cosmic-ray mass composition unambiguously. It also presents a unique opportunity to learn more about nonperturbative QCD in hadron—nucleus collisions. We will review the status of the Muon Puzzle and discuss an outlook for the future.     

铁纳米粒子的结晶形态与表面氧化膜分析

铁纳米粒子样品系采用气体蒸发法制备,用透射电子显微镜观察其结晶形态和粒径大小,采用X射线衍射、电子衍射、X射线光电子能谱和俄歇电子能谱等多种分析手段详细分析了粒子表面氧化膜的组成、结构和厚度及其稳定性,提出了铁纳米粒子组成和结构模型。结果发现铁纳米粒子本身的晶体结构与普通α-Fe是一致的,为体心立方结构,粒子表面存在约3nm厚的双层氧化膜,外面一层为γ-Fe₂O₃,厚度约为1nm。里面一层为Fe₃O₄,厚度约为2nm, 关键词：     

Fluctuation analysis of meteo-marine data

We study long-term behaviour of air temperature, wave heights and wind speed time series recorded for the period 1993–1997 at a meteo-marine station located in the Adriatic Sea. The scaling analysis shows that fluctuations of air temperature display long-range autocorrelations, while those for wave heights show a more complex behaviour, crossing over from a persistent regime at intermediate time scales (up to about 20 days) to an anti-persistence behaviour at longer times. Furthermore, the crosscorrelations of their records are found to be large, with a covariance of about -0.3 (indicating anti-crosscorrelations) within the full 5-years period, giving a quantitative measure of the actual coupling between the two data sets. Wind speed fluctuations are found to be strongly crosscorrelated (about 0.6) with those of wave heights, indicating as expected that wind is the main driving force for wave height fluctuations.     

干湿表测量氢冷发电机氢气湿度的研究

1引言在我国火力发电厂中，目前普遍使用阿斯曼通风式干湿表测定氢冷汽轮发电机内冷却介质氢气的绝对湿度，在实际测量中由于没满足干湿表使用所需的测量条件和测量操作不得法，所以测量结果相对偏差很大。往往是同一时刻、同一工况下、不同的测量者得出差别很大的测量结果，这种相对误差可高达30～50％。这种状况往往造成对发电机氢气湿度监控的误导而导致发电机内湿度严重超标，已经诱发了多次机组事故，给国民经济造成了巨大损失[1]。因此弄清干湿表测定氢冷发电机氢气湿度的误差来源，找到消除误差的措施对于发电机氢气湿度实施准确严格…     

Influence of the balance of the intertropical front on seasonal variations of the isotopic composition in rainfall at Kisiba Masoko (Rungwe Volcanic Province,SW, Tanzania)

Tropical rainfall isotopic composition results from complex processes. The climatological and environmental variability in East Africa increases this complexity. Long rainfall isotope datasets are needed to fill the lack of observations in this region. At Kisiba Masoko, Tanzania, rainfall and rain isotopic composition have been monitored during 6 years. Mean year profiles allow to analyse the seasonal variations. The mean annual rainfall is 2099?mm with a rain-weighted mean composition of ?3.2?‰ for δ¹⁸O and ?11.7?‰ for δ²H. The results are consistent with available data although they present their own specificity. Thus, if the local meteoric water line is δ²H?=?8.6 δ¹⁸O?+?14.8, two seasonal lines are observed. The seasonality of the isotopic composition in rain and deuterium excess has been compared with precipitating air masses backtracking trajectories to characterize a simple scheme of vapour histories. The three major oceanic sources have two moisture signatures with their own trajectory histories: one originated from the tropical Indian Ocean at the beginning of the rainy season and one from the Austral Ocean at its end. The presented isotopic seasonality depends on the balance of the intertropical front and provides a useful dataset to improve the knowledge about local processes.     

EMMA—a new underground cosmic-ray experiment

An experiment observing underground muons originating from cosmic-ray air showers is under preparation in the Pyhäsalmi mine, Finland. The aim is to cover an area of about 200–300 m², and the detector setup is capable of measuring the muon multiplicity and their lateral distribution. The detector is placed at a depth of about 85 m (corresponding about 240 m w.e.), which gives a threshold energy of muons of about 45 GeV. The detection of the multimuon events is motivated by partly unknown composition of the primary cosmic rays in the energy region of 10¹⁵–10¹⁶ eV, i.e., the knee region. In addition, by measuring only the higher energy muons of the air shower, the lowest energy muons being filtered out by the rock overburden, the data is sensitive also to the studies of the upper parts of the air shower. The experiment will be constructed mainly using drift chambers used previously in LEP detectors at CERN, but it can also be expanded using plastic scintillator detectors. The prototype detector is expected to be running in the beginning of 2006, and the full-size detector by the end of 2007.     

Measurement of multi-muon events in a flash chamber tracking calorimeter at sea level

Summary The rate and angular distribution of multi-muons events in extensive air showers (EAS) are measured at sea level by a high-efficiency flash chamber calorimeter with an angular resolution of about 0.5°. Data are compared with the predictions of the low-energy composition model (LEC) of the primary cosmic-rays energy spectrum in the range (10¹⁴”10¹⁶) eV and agreement has been found. The measured time correlation between multi-muons events is also discussed. No anomaly has been found. Partially supported by Ministero della Pubblica Istruzione. Marcello Conversi died on September 27, 1988. The present paper is dedicated to his memory.     

The upgrade of endcap CMS muon system

The configuration and composition of the CMS muon system are presented. The paper is focused on cathode strip chambers (CSC) used as the endcap muon system detectors. The goals and objectives of the endcap muon system upgrade are formulated. The main results of works accomplished for the ME1/1 CSCs upgrade and the new ME4/2 muon station construction during the LHC Long Shutdown-1 (2013–2014) are presented. The improved performances of the endcap muon system are shown using experimental data obtained after the upgrade (Run2 data).     

The secondary-electron yield of air-exposed metal surfaces

The secondary-electron-yield (SEY) variation of atomically clean metal surfaces due to air exposure and during subsequent heat treatments is described. As an example SEY results are presented for the case of a sputter-deposited Nb thin film. Corresponding variations in the surface chemical composition have been monitored using AES and SSIMS. On the basis of these results, and of previously obtained SEY results for metals and metal oxides, the origin of the SEY variations is discussed. The SEY increase, which is generally observed during long-lasting air exposure of clean metals, is mainly caused by the adsorption of an airborne carbonaceous contamination layer. The estimated value of about three for the maximum SEY of this layer is higher than that of all pure metals. Only in some cases can the air-formed oxide contribute to the air-exposure-induced SEY increase, while many oxides have a lower SEY than their parent metals. From the experimental data it can also be excluded that the SEY increase during air exposure is mainly due to an increased secondary-electron escape probability. Received: 17 June 2002 / Accepted: 25 June 2002 / Published online: 15 January 2003 RID="*" ID="*"Corresponding author. Fax: +41-22/767-9150, Email: Christian.Scheuerlein@cern.ch     

Katabatic winds in the lower Tamar Valley, Tasmania

Summary As an integral part of an air quality study undertaken in the lower Tamar Valley, Tasmania, where Bell Bay industrial area is located, 10-m surface winds were monitored by six Lambrecht Woelfle type anemographs along the valley between Low Head (near the coast) and Dilston (27km SE of Bell Bay industrial area) in 1982–1983. A tethered balloon was also used to investigate the temperature and wind profiles within the lowest 1 km of the atmosphere in the industrial area. This paper presents some of the results obtained. It mainly focuses on the katabatic winds which affect the dispersion of atmospheric emissions from various sources in the lower Tamar Valley, particularly those from the aluminium smelter, the ferro-alloys smelter, and the 2×120 MW oil-fired thermal power station, which are located in or near the industrial area. The characteristics of the katabatic winds are identified, and their implications for air pollution problems in the study area are discussed. In memory of Dr. R. Jones, foundation director of the Centre for Environmental Studies, the University of Tasmania, Australia. Paper presented at the GNFAO/EURASAP Meeting, Turin, September 1989. To speed up publication, proofs were not sent to the author and were supervised by the Scientific Committee.     

Power penalty in multitone radio-over-fibre system employing direct and external modulation with optical amplifiers

This paper presents a multitone RoF system employing a central station and a remote antenna station to transmit modulated microwave or mm-wave signals. Two configurations of the system employing direct and external modulation are presented. First, at the central station, the modulating signal is directly and externally modulated at 1549.5 and 1550.5 nm, respectively, and the combined signal is then transmitted using wireless mode. In the second configuration, the combined signal is transmitted over 20 km to the remote antenna station using optical fibre connectivity. At the remote antenna station, both channel wavelengths are separated and amplified with an EDFA and SOA and are detected. The demonstration results show that there exists a small power penalty between the direct and the external modulation. But a large power penalty is reported depending upon the choice of optical amplifier viz. EDFA or SOA. Better performance is recorded in later case. The results also show that power is being distributed among the operating frequency and sidebands adjacent to it after transmission over a fibre link.     

Rain Height in Relation to 0°C Isotherm Height Over Some Indian Tropical Locations and Rain Attenuation for an Indian South Coastal Station for Microwave and Millimeter Wave Communication Systems

There is a dearth of results on rain height over Indian tropical stations.The results on rain height in relation to 0°C isotherm height over four stations having different latitudes are presented in this paper. Four stations have been chosen in such a way that all have different latitudes and are located in different geographical regions having different local weather conditions. The seaonal variation of rain height in relation to 0°C isotherm height has been found to be appreciable over the station located in Indian east coast and Gujarat region, while seasonal variation is not significant at lower and intermediate probability levels over the stations located in Indian south-east coast and island. The prevailing local weather conditions over different stations also have been discussed. Based on observed rain heights and rain rates, the attenuation of radio wave at different frequencies lying in the range from 10 GHz to 150 GHz for different probability levels over Indian south-east coastal station have been deduced and presented in this paper.     

漂浮式无坝水电站的研究与分析

本文针对传统的筑坝式水电站存在的一些问题,提出了一种新颖的漂浮式无坝水电站的方案构想,并对其技术经济及环保可行性进行了初步分析研究。分析结果表明,漂浮式无坝水电站能对自然流动的江河水流能进行有效利用,提供真正的绿色水电,而且投资少,方便易建,适合作为临水地区的分布式能源。该方案有望为科学合理地开发利用水力资源提供一种新的途径。     

The Global Methane Cycle: Isotopes and Mixing Ratios,Sources and Sinks

Abstract

A review of the global cycle of methane is presented with emphasis on its isotopic composition. The history of methane mixing ratios, reconstructed from measurements of air trapped in ice-cores is described. The methane record now extends back to 420 kyr ago in the case of the Vostok ice cores from Antarctica. The trends in mixing ratios and in δ¹³C values are reported for the two Hemispheres. The increase of the atmospheric methane concentration over the past 200 years, and by 1% per year since 1978, reaching 1.7 ppmv in 1990 is underlined.

The various methane sources are presented. Indeed the authors describe the methane emissions by bacterial activity under anaerobic conditions in wet environments (wetlands, bogs, tundra, rice paddies), in ruminant stomachs and termite guts, and that originating from fossil carbon sources, such as biomass burning, coal mining, industrial losses, automobile exhaust, sea floor vent, and volcanic emissions. Furthermore, the main sinks of methane in the troposphere, soils or waters via oxidation are also reported, and the corresponding kinetic isotope effects.     

激光渗碳渗硼及其机理的初探

本文叙述了用一台输出功率为500—2000W的连续CO₂激光器,在20钢表面上实现了渗碳、渗硼的实验方法,并对激光处理后的样品,从相的组成、形貌、硬度分布及耐磨性能等方面作了综合分析。实验结果表明:样品表面的化学成份、显微组织和机械性能发生了根本性转变。同时对激光处理过程的机理也作了初步的探讨。 关键词：     

考虑空气阻力时铅球最佳投掷角的参数方程和实用方程

指出了一些文章在讨论有空气阻力作用时关于球类运动的微分方程中存在的问题,得出了空气阻力与速度平方成正比时的微分方程及近似解,计算了最佳投掷角的参数方程,还导出了空气阻力与速度成正比时铅球最佳投掷角的实用方程.     

Birefringence study of photonic crystal fibers by using the full-vectorial finite element method

Modal solutions of photonic crystal fibers with equal and unequal circular air holes in a hexagonal matrix are presented, by using a rigorous full-vectorial finite element-based approach. The effective indices, mode field profiles, spot-sizes, modal hybridness, modal birefringence and group velocity dispersion values have been determined and presented. The effects of the pitch-distance, hole diameter, structural asymmetry, air hole arrangement and the operating wavelength on the modal birefringence are also reported. It is shown that a significant value of birefringence can be achieved by using only circular air holes, which would be easy to fabricate, and by operating it close to its modal cutoff. PACS 42.81.Qb; 42.81.Gs; 42.25.Bs; 31.15.Pf     

某型压缩空气站自动监控报警器系统设计

针对某型压缩空气站日常维护保障需求,设计开发了一款压缩空气站自动监控报警器。该自动监控报警器系统通过信号隔离变送器,实时采集滑油压力信号、水温油温信号、转速信号、压缩空气压力等信号,由系统微型控制器模块进行ADC采集、转换并处理。系统微型控制器采用STC12单片机,运行嵌入式控制程序,对采集到的各类信号进行显示、阈值判断和报警等处理。该自动监控报警器能实时监控压缩空气站的多个关键运行参数并自动报警,有利于压缩空气站的安全运行与操作。     

DCCA cross-correlation coefficient apply in time series of air temperature and air relative humidity

In this paper we propose, analyze and also quantify cross-correlations between climatological data. For this purpose we adopt the DCCA cross-correlation coefficient ρ_DCCA. In order to accomplish this goal, we calculate the cross-correlation between time series of air temperature and relative humidity. This analysis was performed taking into account several stations (cities) around the world. The results found here, depending on the station location, may exhibit one of the following behaviors, i.e., negative, positive, or null cross-correlations. It is noteworthy that, the level of cross-correlation between air temperature and relative humidity is quantified in these cases. Finally, DCCA cross-correlation coefficients show that, in general, the data are influenced by seasonal components.