Subjects: Astronomy >> Astrophysical processes submitted time 2021-09-29 Cooperative journals: 《天文研究与技术》
Abstract： 射电天文中，频谱仪作为接收机后端的频谱分析设备，由于实时性和噪声低等严格要求与商业通用频谱仪有很大区别。射电天文频谱仪经过几代发展，已经发展为以模数转换器（Analog-to-Digital Converter,ADC）和现场可编程阵列（Field Programmable Gate Array,FPGA）等芯片为基础的实时数字频谱仪。实时数字频谱仪具有宽的带宽，高的频率分辨率，高的动态范围，长时间的稳定性等方面的优势，更重要的是，具有体积小，环境要求宽松等特点。德令哈13.7米望远镜接收机后端有18路实时数字快速傅里叶变换（Fast Fourier Transform, FFT）频谱仪。介绍13.7米望远镜的实时数字FFT频谱仪的性能和维护。
Subjects: Astronomy >> Astrophysical processes submitted time 2021-09-29 Cooperative journals: 《天文研究与技术》
Abstract：三维升降转台是高海拔宇宙线观测站(LHAASO)广角切伦科夫望远镜阵列(WFCFA)成像激光雷达标定系统的核心组成部分，主要由慢控子系统、机械子系统和标准零点子系统构成，用于精确控制激光束的出射方向。本文采用高精度数字图像处理技术对三维升降转台的性能进行研究，结果表明其旋转和升降定位精度分别为0.005°和0.056 mm、重复精度分别为0.003°和0.075 mm，满足成像激光雷达标定系统的实验要求。三维升降转台的自动控制巡航功能，有效减少了人工干预，提高了系统远程使用的可靠性和效率。标准零点的校准功能可以有效地监测三维升降转台的定位精度并且在失准的情况下，能够实现远程校准，以确保三维升降转台长期高精度稳定运行。
Subjects: Astronomy >> Astrophysical processes submitted time 2021-09-29 Cooperative journals: 《天文研究与技术》
Abstract：搜集了3C 279的29个态的宽带能谱（Spectral Energy Distributions，SEDs）作为样本，使用稳态拐折幂律电子能谱分布（Electron Energy Distribution，EED）情况下的单区、均匀轻子模型进行拟合，进而研究该源光变时外在观测与内在物理特性及它们之间的关系。主要结果如下：（1）我们的结果支持光变的激波解释（但需要斜激波）或磁重联解释。（2）外康普顿（External Compton，EC）峰的峰值光度log〖ν_EC^pk L〗_EC^pk和磁场logB之间存在一个显著的反相关关系。多普勒因子logδ和外康普顿峰的峰值光度logν_EC^pk L_EC^pk之间存在正相关关系，意味着多普勒因子的增加是外康普顿峰的峰值光度升高的原因之一。（3）同步峰值频率logν_syn^pk和峰值光度logν_syn^pk L_syn^pk之间不存在显著的正相关关系，意味着反耀变体序列不一定对所有耀变体成立。（4）参数U_e/U_B（相对论电子能量密度与磁场能量密度的比值）远离1，说明相对论电子与磁场之间均分趋势不明显，并且参数U_e/U_B中比值大于1的占86%，意味着3C 279中的喷流大多数以粒子为主导；从P_B （磁场功率）0.5表明3C 279喷流中的能量大概率也是由冷质子携带的。同时，我们发现3C 279中γ-ray耗散区位于距离黑洞中心0.1~1.8pc处，暗示着它们位于宽线区（Broad-Line Region，BLR）之外，尘埃环（Dusty Torus，DT）之内。
Subjects: Astronomy >> Astrophysical processes submitted time 2021-09-29 Cooperative journals: 《天文研究与技术》
Abstract：瞬时射频干扰（RFI）信号是最难以识别并消除的一类干扰。针对射电天文观测过程中遇到瞬时RFI问题，本文提出了一种基于RFI信号峰值的特征提取方法，利用该方法生成了RFI信号的特征模板，并基于动态时间规整（DTW）算法和打分策略设计了特征识别算法，实现了RFI信号识别以及分类功能。利用ARRL官网提供的RFI数据完成了特征模板的交叉验证对比，测试结果显示RFI特征模板与同类别RFI相似度高，表明该算法能够对RFI进行识别和分类，该算法为瞬时RFI的特征提取以及识别提供了一种新思路。
Subjects: Astronomy >> Astrophysical processes submitted time 2021-09-29 Cooperative journals: 《天文研究与技术》
Abstract：快速射电暴（Fast Radio Burst，FRB）是目前射电天文领域的主要热点前沿。其相关研究被《自然》（Nature）杂志评选为2020年十大科学发现之一。FRB爆发时间极短且鲜少重复的特点，使其观测捕捉到的概率极低。由人工从海量的天文观测数据中识别FRB事件是件耗时费力的工作。机器学习技术的蓬勃发展为实时搜寻与多频段联合跟踪观测FRB带来了可能。该文从传统机器学习方法和深度学习方法两个方面，对该研究已有的成果进行了分析与总结，并探讨了基于机器学习的FRB搜寻技术目前存在的问题和面临的挑战，分析了其未来发展趋势。
Subjects: Astronomy >> Astrophysical processes submitted time 2021-09-29 Cooperative journals: 《天文研究与技术》
Abstract：卫星对地观测及导航定位的快速发展对地球同步轨道（Geostationary Earth Orbit, GEO）卫星的定轨精度有了米级甚至更高的需求。本文研究利用甚长基线干涉（Very Long Baseline Interferometry, VLBI）时延数据进行GEO卫星快速定位的方法。首先对VLBI时延进行理论精度分析，然后利用中国VLBI网进行GEO卫星观测试验及数据相关处理，最后利用短时VLBI时延数据完成对GEO卫星的定位计算。针对时延中存在与测站和基线相关的异常值问题，本文提出了相应的检测校正方法。数据经校正后重新处理，得VLBI残余时延测量精度约0.16ns，等效于约0.58米的卫星横向位置误差。本文的研究可用于GEO卫星的快速高精度定位及轨道快速恢复。
Subjects: Astronomy >> Astrophysical processes submitted time 2021-09-29 Cooperative journals: 《天文研究与技术》
Abstract：VLBI观测站的氢原子钟和时间比对系统（简称时频系统）为测站提供稳定可靠的时间和频率基准，系统信号的质量将直接影响观测数据质量。其中，氢原子钟是时频系统的关键设备，一旦出现故障，其对数据的破坏是致命的。因此，VLBI站时频系统在设计建设之初就对氢原子钟及其周边各参数状态进行了实时监视并进行记录保存，一旦发现异常，技术人员需进行快速处理。中国VLBI网（CVN）建成至今，目前共五个测站，每个测站的时频系统都配有两台或以上的氢原子钟，系统长期运行以来积累了大量数据，通过对这些数据的分析，我们可以研究氢原子钟状态变化、性能变化、及环境变化之间关系，然后建立故障预测模型从而对设备故障进行预测。本文描述创建时频系统数据仓库，利用数据挖掘技术预测系统故障的测试过程，从测试结果可知在本项目中可以用聚类模型进行很好的预测。
Subjects: Astronomy >> Astrophysical processes submitted time 2021-09-29 Cooperative journals: 《天文研究与技术》
Abstract：射电天文接收机中频系统是接收机的重要组成部分，接收机的L、S、C、K波段的左圆极化和右圆极化信号在高频仓通过下变频成为中频信号。中频信号通过同轴电缆传送到观测室。观测室距离射电望远镜高频仓较远，因此线损较大，且不同频率的信号损耗不同，频率越高损耗越大，导致中频信号功率较小且增益平坦度随频率增加而降低。设计了四通道均衡放大模块，提高中频信号增益并补偿增益平坦度。该模块的均衡器采用了集总元件和微带线相结合的方式，具有结构紧凑、易于集成、成本低的优点。测试结果表明，在6倍频带宽内，均衡量≥8dB，均衡后功率平坦度≤3.5dBm，回波损耗≤-15dB，满足了射电天文中频检测系统的要求。
Subjects: Management Science >> Management Metrology Subjects: Information Science and Systems Science >> Systematology Subjects: Statistics >> Economic Statistics submitted time 2021-09-27
Abstract： Economic development and progress make the production process more and more complex. The complexity index can reflect the level of technological progress of the economic and industrial sectors. This paper revises an index of economic complexity based on Input-output Technology, which is used to analyze the industrial sector and the overall level of technological progress of regions. The empirical results show that the modified complexity index can well express the level of economic and technological progress of economic and industrial sectors, which is more reasonable than the calculation formula before the modification.
Peer Review Status:
Awaiting Review
Subjects: Physics >> Electromagnetism, Optics, Acoustics, Heat Transfer, Classical Mechanics, and Fluid Dynamics Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology submitted time 2021-09-27
Abstract： Magnetism and magnetic monopole are classical issues in physics. Conventional magnets are generally composed of rigid materials which may face challenges in extreme situations. Here, from an alternative other than rigid magnet, we proposed for the first time to generate fluidic endogenous magnetism and construct magnetic monopole through tuning liquid metal machine. Based on theoretical interpretation and conceptual experimental evidences, we illustrated that when gallium base liquid metal in solution rotates under electrical actuation, it forms an endogenous magnetic field inside which well explains the phenomenon that two such discrete metal droplets could easily fuse together, indicating their reciprocal attraction via N and S poles. Further, we clarified that the self-fueled liquid metal motor also runs as an endogenous fluidic magnet owning electromagnetic homology. When liquid gallium in solution swallowed aluminum inside, it formed a spin motor and dynamically variable charge distribution which produced endogenous magnetism inside. This explains the phenomena that there often happened reflection collision and attraction fusion between running liquid metal motors which were just caused by the dynamic adjustment of their N and S polarities, respectively. Finally, we conceived that such endogenous magnet could lead to magnetic monopole and four technical routes to realize this object were thus suggested as: 1. Matching interior flow of liquid metal machines; 2. Superposition between external electric effect and magnetic field; 3. Composite construction between magnetic particles and liquid metal motor; 4. Chemical ways such as via galvanic cell reaction. Overall, the present theory and revealed experimental evidences disclosed the role of liquid metal machine as a fluidic endogenous magnet and pointed out some promising ways to realize magnetic monopole. A group of unconventional magnetoelectric devices and applications can be possible in the near future.
Peer Review Status:Awaiting Review
Subjects: Psychology >> Social Psychology Subjects: Psychology >> Applied Psychology submitted time 2021-09-26
Abstract： It is usual for individual to feel socially excluded. As an unpleasant experience, social exclusion results in adverse effect on individual’s cognitive, physical and psychological functions. Social exclusion refers to a feeling of being ignored, rejected or isolated by other individuals or social groups. Previous studies have shown that individuals generally resort to consumption to alleviate the negative effects of social exclusion, for example, they have a preference for unique products and anthropomorphic products after being socially excluded. van Boven & Gilovich (2003) classified purchases into two types: experiential purchase and material purchase. Experiential purchase refers to those made with the main purpose of obtaining life experience such as watching a movie and going to a concert while material purchase refers to those made with the main purpose of obtaining a tangible good such as buying accessories and clothes. However, so far there are few studies attempting to examine the effect of social exclusion on experiential purchase and material purchase. The current research aims to explore the effect of social exclusion on experiential purchase and material purchase. Meanwhile, this research also interested in investigating the factors that might moderates the effects of social exclusion on experiential purchase and material purchase and factors that might mediate the moderating effects. Study 1a and 1b respectively used a single-factor (social exclusion vs. social inclusion) between-subject design to explore the effect of social exclusion on consumer purchase. Participants were asked to take times to imagine that they were the protagonist of the story and reported which consumption activity (experiential purchase or material purchase) to get involved after reading the story. In study 2, a two-factor (social exclusion vs. social inclusion; nostalgia vs. control) between-subject design were employed to investigate the moderating role of nostalgia and mediating role of social connectedness. Participants were randomly assigned to the socially included group or the socially excluded group. Social exclusion and inclusion were manipulated in the same way as study 1. Right after the exclusion or inclusion manipulation there was another task requiring participants to recall a nostalgic event or an ordinary event in order to manipulate nostalgia. Participants were also randomly assigned to nostalgic group and control group. Then they were required to report their feelings of social connectedness and decide which purchase (experiential purchase or material purchase) to have. Our findings are as follows：(1) Compared with those who are socially included, socially excluded individuals are more likely to have experiential purchase over material purchase. (2) Nostalgia moderates the effect of social exclusion on purchase. Specifically, after being socially excluded, there is a significant difference on the purchase decision between nostalgic individuals and control ones. Participants in the control group prefer to choose experiential purchase more than nostalgic individuals. However, for those who are socially included, there is no significant difference on purchase decision between nostalgic group and control one. (3) Social connectedness mediates this moderation effect. Taken together, these findings indicate that socially excluded consumers have a tendency towards experiential purchase, which enriches the researches of the antecedent of experiential purchase and the consequence of social exclusion. Furthermore, it reveals an important underlying mechanism to cope with the negative influence of social exclusion.
Peer Review Status:Awaiting Review
Subjects: Psychology >> Social Psychology Subjects: Psychology >> Applied Psychology submitted time 2021-09-26
Abstract： Consumers will inevitably receive some information about death in their daily life. For example, they see news reports on social media about traffic accidents, air crashes, terrorist attacks, wars, major disasters (earthquakes, floods, tsunamis, etc.), and sudden death, which contain death information. Another example is knowing or experiencing the unfortunate news that friends, relatives and strangers passed away due to disease or accident in their lives. This is especially true in the context of the current COVID-19 epidemic, where the number of COVID-19 deaths continues to rise globally and consumers are exposed to the threat of death, either passively or actively. According to previous studies, under the influence of death threat information, consumers may have stronger desire to consume and make consumption in response to death threat. So, when consumers think about the possibility of death or are exposed to mortality salience, will they be more willing to engage in experiential consumption or material consumption? Do mortality salience have an impact on consumers' preference for experiential products? What are the mechanisms and boundary conditions? In experiment 1, participants were asked two classic death questions to conduct death reminders, and then the effect of mortality salience on the number of experiential products consumers chose was tested. In experiment 2, the effect of mortality salience on consumers' preference for experiential product selection was repeatedly verified by reading traffic accident news reports. The mediating role of meaning in life between mortality salience and consumers' choice preference of experiential products was explored. Experiment 3 was based on the background of the current COVID-19 epidemic, and mortality salience was activated by asking the subjects to read reports about COVID-19 deaths. Moreover, the boundary conditions of the effect of mortality salience on consumers' choice preference of experiential purchases were further explored from the intervention level by manipulating the level of social support in experiment 3. The main results of the study are as follows: (1) Mortality salience will improve consumers' preference of experiential purchase and increase the number of experiential products to choose. (2) Meaning in life played a mediating role in the relationship between mortality salience and the preference of experiential purchase. (3) Social support moderated the effect of mortality salience on meaning in life. When social support was low, mortality salience was negatively correlated with meaning in life. When social support was high, there was no significant correlation between mortality salience and meaning in life. (4) Social support moderated the mediating effect of meaning in life on mortality salience and consumer preference of experiential purchase . When social support was low, the mediating effect was established. When social support was high, the mediating effect did not hold. The findings suggest that death mortality salience is an antecedent variable that influencing consumers' direct choice between experiential and material consumption, enriching and expanding relevant research in the field of consumer preferences, while providing reference implications for maintaining individual physical and mental health and restoring socioeconomic development in the post-epidemic period.
Peer Review Status:Awaiting Review
Subjects: Psychology >> Clinical and Counseling Psychology Subjects: Psychology >> Applied Psychology submitted time 2021-09-26
Abstract： " Shame is a core hidden negative emotion, which plays an important role in the process of substance abuse and withdrawal. The concept of shame is complex with plenty of measurements, whose influence on substance abuse is modulated by sex, emotion, culture, and the controllability of self-image. Substance abuse groups intervention based on shame include Alcoholics Anonymous, Narcotics Anonymous, Acceptance and Commitment Treatment, and Cognitive Behavior Treatment. Under the Chinese Culture, the substance abuse group intervention model based on shame needs further investigation. " " "
Peer Review Status:Awaiting Review
Subjects: Psychology >> Social Psychology Subjects: Psychology >> Management Psychology submitted time 2021-09-26
Abstract： Time and money are two important resources which could affect consumer decision-making differently. When consumers making purchase decisions, they are ususally influenced by the information of time or money which implied in the merchant’s slogan and the shopping environment. And these affect would be differential in consumers’ purchase decision process such as pre-purchase stage, purchasing stage, and post purchase stage. From the perspective of dual-process theory, the psychological mechanism may be due to different cognitive processing mindsets that primed by time and money. Future research should further explore the following issues: (1) Elaborating the different effects of priming time and money on purchase decisions. (2) Considering the impact from the trade-off between time and money on purchase decisions. (3) Further exploring the different influences of priming time and money on the pre-purchase decision. (4) Exploring the neural mechanisms underlying the different effects of time and money on purchase decisions. "
Peer Review Status:Awaiting Review
Subjects: Civil Engineering and Building Construction >> Building Materials submitted time 2021-09-25
Abstract： " The waste rice husk ash produced by the biomass power plant was added to the concrete instead of part of the cement to prepare a new type of electric power plant-rice husk ash (E-RHA-C) concrete (E-RHA-C). ), the mechanical properties of E-RHA-C and the durability test of 210d Na2SO4 erosion and 105 cycles of dry and wet Na2SO4 solution were carried out. Combined with its macro-mechanical and physical parameters and micro-morphology, the mechanical strength and sulfate resistance of E-RHA reinforced concrete were tested. The mechanism of erosion ability is analyzed, and the durability of E-RHA-C is evaluated by the energy conversion method, and the corresponding constitutive model is obtained. The results show that: ordinary concrete mixed with a proper amount of rice husk ash mineral admixture can effectively improve the mechanical properties, but the stability of the concrete mechanical properties increases gradually decreases. As the sulfate age increases, the E-RHA-C specimens gradually peel off locally and expand in volume; the mechanical properties and relative dynamic elastic modulus first increase and then drop sharply, and the effective porosity first decreases and then increases. E-RHA-C bone The damage degree of the interface zone around the material is much smaller than that of ordinary concrete, which shows better corrosion resistance. The enhancement of the mechanical properties of the specimens in the early stage of E-RHA-C by sulfate attack is mainly manifested in the increase of total strain energy and dissipation energy, and the increase of E-RHA-C plasticity and ductility deformation. In the second stage, E-RHA-C gradually manifests the peak stress and ductility reduction, and the obvious phenomenon of brittle failure. Based on statistical damage theory and dissipated energy, a constitutive model of durability damage of E-RHA-C is established.
Peer Review Status:Awaiting Review
Subjects: Psychology >> Applied Psychology submitted time 2021-09-24
Abstract： [Objective] Measuring people’s attitude towards COVID-19 vaccination is relatively distinctive from an attitude over a general conflict. [Methods] An online survey of 3123 respondents from China’s 30 provinces and municipalities (except Tibet Autonomous Region) was conducted from January 22 to 27, 2021 to measure their willingness to be vaccinated. [Results] Over half of the respondents chose the options ‘not to be vaccinated now’ and ‘wait and see before making a vaccination decision’, thereby indicating that people’s willingness to be vaccinated is not as optimistic as anticipated in the early stage of vaccination in China. [Conclusions] Researchers should carefully choose survey methods to investigate people's real willingness to vaccination. It is suggested that relevant departments should fully anticipate and prepare for people's "vaccination hesitation" " "
Peer Review Status:Awaiting Review
Subjects: Psychology >> Cognitive Psychology submitted time 2021-09-24
Abstract：在日常生活和购物环境中，混乱无序无处不在。然而，关于环境无序性对消费者产品选择行为的影响研究却十分有限，本文试图填补这一不足。具体而言，本文创新性地提出环境无序性与多样化寻求行为之间存在着因果关系，且自我效能威胁和未来偏好不确定感在其中发挥链式中介作用。通过1个预实验和4个实验，本文发现无论在真实环境、线下购物环境、工作环境，还是线上产品陈列情境下，环境无序性均可提升多样化寻求行为；无序的环境会对消费者的自我效能产生威胁，进而增强其对未来产品偏好的不确定性感知，最终促使其通过增加多样化寻求行为来应对未来可能变化的产品偏好。
Peer Review Status:Awaiting Review
Subjects: Library Science，Information Science >> Readers Work submitted time 2021-09-22
Abstract： The purpose of this paper is to accurately grasp the current situation and development trend of research on the services for children and young adults in public libraries in China, to sort out and analyze the shortcomings and defects of the existing researches, and to provide a better reference for future research. Through a literature search of Chinese and English studies on this domain, 3,224 papers were classified into five categories according to research methods, and each category and its subcategories were systematically reviewed. The study found that the research on public library services for children and young adults had a variety of topics. It has a wide range of contents and fit the national requirements and social needs. It mainly focused on the interests of special groups and had its own research characteristics. At the same time, the proportion of non-empirical studies was large, there were fewer studies with depth and persistence, and the international influence was very small. In the future, we should actively draw on the empirical paradigms of other social sciences to study the core issues of this discipline and make the research on library services for children aged 0-18 more detailed and in-depth.
Peer Review Status:Awaiting Review
Subjects: Mathematics >> Applied Mathematics submitted time 2021-09-22
Abstract： In the early days of the epidemic of coronavirus disease 2019 (COVID-19), due to insufficient knowledge of the pandemic, inadequate nucleic acid tests, lack of timely data reporting, etc., the origin time of the onset of COVID-19 is difficult to determine. Therefore, source tracing is crucial for infectious disease prevention and control. The purpose of this paper is to infer the origin time of pandemic of COVID-19 based on a data and model hybrid driven method. We model the testing positive rate to fit its actual trend, and use the least squares estimation to obtain the optimal model parameters. Further, the kernel density estimation is applied to infer the origin time of pandemic given the specific confidence probability. By selecting 12 representative regions in the United States for analysis, the dates of the first infected case with 50% confidence probability are mostly between August and October 2019, which are earlier than the officially announced date of the first confirmed case in the United States on January 20, 2020. The experimental results indicate that the COVID-19 pandemic in the United States starts to spread around September 2019 with a high confidence probability. In addition, the existing confirmed cases are also used in Wuhan City and Zhejiang Province in China to infer the origin time of COVID-19 and provide the confidence probability. The results show that the spread of COVID-19 pandemic in China is likely to begin in late December 2019. " " "
Peer Review Status:Awaiting Review
Subjects: Psychology >> Physiological Psychology submitted time 2021-09-21
Abstract： Task interruption is known to harm work performance, especially on working memory-related tasks. However, little is known about brain activity patterns during task interruption and the moderating effects of mental fatigue. The impact of work interruption on subsequent behavioral performance is mainly caused by affecting working memory (WM) and attention. Therefore, exploring the mechanisms underlying the impact of interruption on work performance in different fatigue states will improve and contribute to the development of the cognitive theory of interruption. Combined with behavioral and electrophysiological data, we adopted the event-related potential (ERP) technique to explore the effect of interruption on working memory and the moderating role of fatigue on the interruption process. We designed a 2 (fatigue: fatigue, nonfatigue) ×2 (task type: task interruption, suspension interruption) ×2 (trial type: before interruption, after interruption) within-group design and added a noninterrupted baseline task as the control condition. The study randomly selected 20 healthy participants to perform spatial 2-back tasks in different fatigue states in various interruption conditions (math problem task interruption, suspension interruption and noninterrupted). A continuous performance test (AX-CPT) was used to induce fatigue before the fatigue session. The behavioral data showed that accuracy in the primary task was reduced, and response time was increased after interruption. The behavioral performance decline in the primary tasks in the fatigue state was more significant than that in the nonfatigue state. ERP results showed that the P200 and P300 amplitudes induced by the 2-back task significantly increased after interruption. The P200 latency in the fatigue state was significantly shorter than that in the nonfatigue state; the latency with task interruption was longer than that with suspension interruption; and the latency after interruption trials was significantly longer than that before interruption trials. The P300 amplitude in the frontal lobe in the fatigue state was lower than that in the nonfatigue state. The amplitude difference between trials after interruption was more significant in the fatigue state than in the nonfatigue state. In addition, the P300 amplitude induced by task interruption was significantly higher than that induced by suspension interruption, while the same effect did not appear in the nonfatigue state. In conclusion, work interruption caused a decrease in the attention resources available for the primary task after the interruption. The irrelevant information in the task interruption interfered with primary task performance (working memory task), and the fatigue state further aggravated the negative effect of the interruption on working memory and attention. This research revealed the cognitive process underlying task interruption, identified the effects of fatigue and supported the memory for goals model of interruption. " "
Peer Review Status:Awaiting Review
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