Average Level Crossing Rate and Fading Duration of Multiuser Single Relay Cooperation Wireless Uplinks

We investigate the average Level Crossing Rate （LCR） and Average Fading Duration （AFD） of multiuser single relay co- operation wireless uplinks over independent and non-identically distributed （i.ni.d） Ray- leigh fading channels. We first present the statistical analyses of the first-hop equivalent envelope. Then, we investigate the LCR and AFD of an equivalent end-to-end envelope, and present the closed-form solutions to LCR and AFD, which are given with integral forms. Finally, we derive the Laplace approximations of LCR and AFD as well as the upper and lower bounds. The numerical results of LCR show that the upper bound is tight. For multi user systems with different number of mobile users, the analyses indicate that the LCRs are approximately the same at the low level of the envelope. envelope However, there are at the high level of the reasonable differences among the curves of LCRs. Due to that fact that AFD is the inverse function of LCR, the results for AFD are the opposite.

100 Hertz frame-rate switching threedimensional orbital angular momentum multiplexing holography via cross convolution

The orbital angular momentum(OAM)of light has been implemented as an information carrier in OAM holography.Holographic information can be multiplexed in theoretical unbounded OAM channels,promoting the applications of optically addressable dynamic display and high-security optical encryption.However,the frame-rate of the dynamic extraction of the information reconstruction process in OAM holography is physically determined by the switching speed of the incident OAM states,which is currently below 30 Hz limited by refreshing rate of the phase-modulation spatial light modulator(SLM).Here,based on a cross convolution with the spatial frequency of the OAM-multiplexing hologram,the spatial frequencies of an elaborately-designed amplitude distribution,namely amplitude decoding key,has been adopted for the extraction of three-dimensional holographic information encoded in a specific OAM information channel.We experimentally demonstrated a dynamic extraction frame rate of 100 Hz from an OAM multiplexing hologram with 10 information channels indicated by individual OAM values from-50 to 50.The new concept of cross convolution theorem can even provide the potential of parallel reproduction and distribution of information encoded in many OAM channels at various positions which boosts the capacity of information processing far beyond the traditional decoding methods.Thus,our results provide a holographic paradigm for high-speed 3D information processing,paving an unprecedented way to achieve the high-capacity short-range optical communication system.

Calculation of Photo-Ionisation Cross Sections and Radiative Recombination Rate Coefficients for CO and CO^+ Molecules

A method based upon the weighted total cross section （WTCS） theory is proposed to calculate the photo-ionisation cross sections and the radiative recombination rate coefficients between the fundamental level of CO and the main electronic states of its corresponding ion. Total photo-ionisation cross sections and radiative recombination rate coefficients are determined from the calculation of elementary vibrational photo-ionisation cross sections. Transitions be- tween CO＋（X, A and B） and CO（X） are considered. Total photo-ionisation cross sections and recombination coefficients are computed in the temperature interval 500-15000 K.

State-to-state integral cross sections and rate constants for the N^(+)(3P)+HD→NH^(+)/ND^(+)+D/H reaction:Accurate quantum dynamics studies

The reactive collisions of nitrogen ion with hydrogen and its isotopic variations have great significance in the field of astrophysics.Herein,the state-to-state quantum time-dependent wave packet calculations of N^(+)(3P)+HD→NH^(+)/ND^(+)+D/H reaction are carried out based on the recently developed potential energy surface[Phys.Chem.Chem.Phys.2122203(2019)].The integral cross sections(ICSs)and rate coefficients of both channels are precisely determined at the state-to-state level.The results of total ICSs and rate coefficients present a dramatic preference on the ND+product over the NH^(+)product,conforming to the long-lived complex-forming mechanism.Product state-resolved ICSs indicate that both the product molecules are difficult to excite to higher vibrational states,and the ND^(+)product has a hotter rotational state distribution.Moreover,the integral cross sections and rate coefficients are precisely determined at the state-to-state level and insights are provided about the differences between the two channels.The present results would provide an important reference for the further experimental studies at the finer level for this interstellar chemical reaction.The datasets presented in this paper,including the ICSs and rate coefficients of the two products for the title reaction,are openly available at https://www.doi.org/10.57760/sciencedb.j00113.00034.

Alcohol drinking rates of male between 7th and 11th graders in Japan decreased gradually based on nationwide repeated cross-sectional surveys from 1996 to 2008

Early drinking is considered to result in making tolerant of alcohol consumption and a higher prevalence of alcohol related disorders in the later. We focused generational impacts on drinking rate among high school students based on multiple nationwide data. The surveys were nationwide, cross-sectional random sampling surveys given every 4 years from the Japanese Youth Tobacco and Alcohol Surveys, 1996 to 2008. Participants were male 53,925 high school students from 7th grade to 11th grade. We divided to the three follow-up groups every 4 years from 1996 to 2004 for male junior high school students in 7th grades and the end periods were 4 years later in 11th grades. Outcome measures in this study were life time drinking, current drinking within 30 days and weekly drinking. All drinking rates decreased each at 7th and at 11th grade. The increments in these drinking rates from 7th grade to 11th grade in males decreased gradually in recent follow-up groups. Generational impacts should be considered by using follow-up groups to study drinking behaviors among students.

Investigation of the ^(121)Sb(α,γ)^(125)I reaction cross-section calculations at astrophysical energies

Proton-rich nuclei are synthesized via photodisintegration and reverse reactions.To examine this mechanism and reproduce the observed p-nucleus abundances,it is crucial to know the reaction rates and thereby the reaction cross sections of many isotopes.Given that the number of experiments on the reactions in astrophysical energy regions is very rare,the reaction cross sections are determined by theoretical methods whose accuracy should be tested.In this study,given that ^(121)Sb is a stable seed isotope located in the region of medium-mass p-nuclei,we investigated the cross sections and reaction rates of the ^(121)Sb(α,γ)^(125)I reaction using the TALYS computer code with 432 different combinations of input parameters(OMP,LDM,and SFM).The optimal model combinations were determined using the threshold logic unit method.The theoretical reaction cross-sectional results were compared with the experimental results reported in the literature.The reaction rates were determined using the two input parameter sets most compatible with the measurements,and they were compared with the reaction rate databases:STARLIB and REACLIB.

Smoking rate trends of male 7th and 11th graders in Japan based on repeated, nationwide, cross-sectional surveys every 4 years from 1996 to 2008

Backgrounds: Smoking in childhood has become an important public health concern. Previous studies have reported on secular trends in childhood smoking rates and compared with smoking rates at fixed ages. They also described secular trends regarding the prevalence of smoking at fixed ages. The variations in smoking rate of young children and adolescents by follow-up groups have not been studied by follow-up groups at a national level. Objective: We looked at trends and generational impacts on smoking rate by using follow-up groups of male Japanese high school students to quantitatively assess differences in trends, based on multiple nationwide data from the Japanese Youth Tobacco and Drinking Surveys gathered every 4 years between 1996 and 2008. Methods: The surveys were nationwide, cross-sectional random sampling surveys given every 4 years from 1996 to 2008, using the single-stage cluster sampling methodology. The cluster unit of the sampling was school. The survey targeted junior and senior high school students from schools selected through Japan using the National School Directory. Students enrolled in the sampled schools were subjects of the study. Participants were 53,925 high school students from 7th grade to 11th grade in 1996, 2000, 2004 and 2008. We divided the three follow-up groups every 4 years from 1996 to 2004 for male junior high school students in 7th grades, age 13. The end periods were 4 years later when they had become 11th graders, age 17, from 2000 to 2008. Main outcome measures in this study were life time smoking, current smoking within 30 days and daily smoking at 7th or 11th grade and the trend of the smoking rates between 7th to 11th grades. Results: Life time smoking rate, current smoking rate and daily smoking rate in Japanese high school students decreased at 7th grade from 1996 to 2004. They also decreased at 11th grade from 2000 to 2008. However, the slopes differed among their follow-up groups. The increments in their smoking rates from 7th grade to 11th grade in male high school students were smaller in recent follow-up groups both in 2000 and in 2004 than in follow-up groups in 1996. Then, those increments in follow-up groups between in 2000 and in 2004 were similar in lifetime smoking rate and current smoking rate. Conclusions: We have shown that monitoring trends by follow-up group are important in studying smoking for public health. Values of smoking rates from a young age to adolescence by follow-up group should be examined. Values of smoking rate and regular changes in smoking rate are important because smoking rate changes dynamically during adolescence. Not only trends in smoking rates at fixed ages, but also generational impacts should be considered by using follow-up groups to study smoking behaviors among students. We need to continue careful monitoring of follow-up group smoking prevalence. When long-term health promotions are planned or assessed, policy makers need to look at changes in follow-up groups.

A NOVEL CROSS-LAYER STRATEGY OF VIDEO TRANSMISSION TO SOLVE PERFORMANCE ANOMALY IN MULTI-RATE IEEE 802.11 NETWORKS

When wireless hosts use different rates to transmit data in IEEE 802.11 networks, it will take on the state of performance anomaly which will severely decrease the throughputs of all the higher rate hosts. Hence, it is bad for video service transmission. Considering that video is very sensitive to packet delivery delay but can tolerate some packet losses, we propose a novel cross-layer scheme which takes these two characteristics into consideration. Firstly, the maximum number of retransmissions for a video Medium Access Control (MAC) frame is computed in MAC layer according to video frame rate requirement of application layer and current access delay of MAC layer. Secondly, within the margin of the tolerant Packet Loss Rate (PLR) of application layer, several video MAC frames are allowed to drop so that we can adaptively select the transmission rate as high as possible for the rest of video MAC frames in terms of current channel quality and the maximum number of retransmissions. Experiment results show that the proposed method can reduce the delay and jitter of video service and improve the throughputs of fast hosts. Therefore, it increases the quality of reconstructed video to a certain extent and relieves the performance anomaly of network effectively.

On Cross-Layer Design of AMC Based on Rate Compatible Punctured Turbo Codes

This paper extends the work on cross-layer design which combines adaptive modulation and coding at the physical layer and hybrid automatic repeat request protocol at the data link layer. By contrast with previous works on this topic, the present development and the performance analysis as well, is based on rate compatible punctured turbo codes. Rate compatibility provides incremental redundancy in transmission of parity bits for error correction at the data link layer. Turbo coding and iterative decoding gives lower packet error rate values in low signal-to-noise ratio regions of the adaptive modulation and coding (AMC) schemes. Thus, the applied cross-layer design results in AMC schemes can achieve better spectral efficiency than convolutional one while it retains the QoS requirements at the application layer. Numerical results in terms of spectral efficiency for both turbo and convolutional rate compatible punctured codes are presented. For a more comprehensive presentation, the performance of rate compatible LDPC is contrasted with turbo case as well as the performance complexity is discussed for each of the above codes.

基于一个新SiH_(2)(1^(1)A′)势能面的H+SiH反应动力学研究

本文基于2022年报道的一个SiH_(2)(1^(1)A′)势能面,运用切比雪夫波包方法对H(^(2)S)+SiH(X^(2)П;v=0;j=0)→Si(^(1)D)+H_(2)(X^(1)∑_(g)^(+))反应体系在1:0×10^(-3)-1.0 eV的碰撞能量范围内进行动力学研究.分别应用忽略科里奥利耦合效应的耦合态近似和精确量子力学计算得到该反应的反应概率、积分散射截面和速率常数.计算发现在J较大时,科里奥利耦合效应显著提升该反应的反应概率,忽略科里奥利耦合效应会使H+SiH反应的积分散射截面和速率常数减小,对于速率常数而言,温度越高,两种计算方法所得结果的差距越大.精确的量子力学计算结果表明,H+SiH反应的速率常数在300-1000 K之间几乎不随温度改变,这与H+CH反应非常相似,但是在数值上,前者比后者大1个数量级.

内蒙古自治区社区5类精神障碍患者精神卫生服务利用现状

目的:描述内蒙古自治区社区5类精神障碍终生患者精神卫生服务利用现况,为健康教育和制定相关政策提供参考。方法:采用分层多阶段不等概率抽样方法抽取内蒙古自治区18岁及以上常住居民共12 315名,采用复合性国际诊断交谈表调查心境障碍、焦虑障碍、物质使用障碍、间歇爆发性障碍、进食障碍等5类精神障碍及精神卫生服务利用现况,以单因素分析方法进行描述性统计。结果:5类精神障碍中,任何一种精神障碍终生患者咨询率为18.7%,治疗率为10.2%,患者接受非医务工作者治疗的比例最高(31.4%),其次是接受精神科或心理科医生治疗;患者中有1.1%的患者接受药物治疗,有2.5%的患者接受心理治疗。结论:内蒙古自治区精神障碍患者精神卫生服务利用率较低,要广泛开展正确求医的健康教育。

澳洲坚果主导品种Own Choice的品种配置研究

为了明确澳洲坚果园主导品种Own Choice(O.C)的最适配置品种,选择HAES863、D、D4、HAES816、HAES906、HAES294、HAES900、A4等8个品种为O.C授粉,统计分析不同授粉处理的着果率、杂交不亲和性程度指数、着果花序率、每果序着果数、落果率、壳果横径等指标。结果表明,以着果率及着果花序率统计的杂交不亲和性程度指数发现,HAES863、D、D4、HAES816、HAES906与O.C的杂交亲和性高于A4、HAES294、HAES900。供试品种处理的着果率与着果花序率之间存在正相关关系,初步推断可使用着果花序率代替着果率评价O.C与不同品种的杂交不亲和性程度;8个授粉处理的平均着果花序率为40.60%,可以此推断O.C与不同授粉品种的田间杂交不亲和性程度。综合分析推断,澳洲坚果主导品种O.C的最适配置品种为HAES863和D4,根据小气候可选择性搭配种植D、HAES906、HAES816。

高重复频率猝发多脉冲加载下交联聚苯乙烯真空沿面闪络特性

基于高重复频率强流多脉冲加速器的应用需求,针对交联聚苯乙烯(XLPS)材料在猝发多脉冲下的真空沿面闪络特性开展了实验研究。采用放置于平板电极中的XLPS圆台样品,在脉宽120 ns的单个脉冲和间隔500 ns的三脉冲加载下开展了真空沿面闪络实验,通过对实验平台和实验规范的优化设计,有效提升了实验效率和数据有效性,观测到了样品发生真空沿面闪络前的试样电压顶降现象和前序脉冲闪络对后续脉冲的显著影响,获得了XLPS材料在相应条件下真空沿面闪络的统计数据。在实验基础上,对XLPS材料在高重复频率多脉冲加载下的真空沿面闪络特性进行了分析,为高重复频率多脉冲加速器的绝缘设计提供了实验依据。

产能分享平台企业的盈利模式选择与定价研究

在分享经济背景下,考虑交叉网络外部性效用及平台匹配率,研究产能分享平台的盈利模式选择与定价问题。基于两阶段博弈方法,分析并比较了平台在利润最大化和社会福利最大化条件下选择服务费模式与注册费模式时获得的最大利润。研究发现,在目标时间段内,当平台以利润最大化为目标时,多数情况下选择注册费模式获得的最大利润高于选择服务费模式获得的利润。在特定条件下,也存在平台采取两种盈利模式会获得相同利润的情况。此外,平台最大利润在一定条件下与交叉网络外部性系数和平台对制造能力供应方的匹配率正相关,与对制造能力需求方的匹配率负相关。当平台以社会福利最大化为目标时,选择服务费模式获得的利润高于选择注册费模式时的利润。最后,通过数值算例对上述结果进行了验证。

声波法在输油管道上的可检测泄漏率分析

为了确保输油管道出现泄漏时能够及时检测到泄漏,对声波法在输油管道上的可检测泄漏率进行了分析。首先,建立了声波产生和传播衰减模型,根据模型分析了声波在管道内的衰减性,得到管道两端声波衰减幅值的计算方法;其次,采用基于互信息优化的自适应噪声完备集合经验模态分解(complete ensemble empirical mode decomposition with adaptive noise,简称CEEMDAN)和互谱分析相结合的去噪算法对采集的信号进行去噪,并实验验证了衰减模型可准确估计声波的衰减幅值,去噪算法可以有效消除信号中的噪声;最后,分析了管道特性与声波法在输油管道上的可检测泄漏率之间的关系。研究表明,管道特性在一定程度上决定了声波法的可检测泄漏率,声波法在输油管道上的最小可检测泄漏率可达0.45%。

2016~2022年昆明市临床分离铜绿假单胞菌耐药性变迁及交叉耐药表型分析

目的了解该院七年来铜绿假单胞菌耐药率变化及耐药表型特征,为铜绿假单胞菌感染早期经验治疗提供依据,并为后期耐药机制研究奠定一定的基础。方法使用Whonet 5.6软件按年统计昆明市第一人民医院2016~2022年从临床标本分离并报告的铜绿假单胞菌药物敏感性数据,以亚胺培南、美罗培南、头孢他啶及头孢吡肟等药物为主要观察对象,统计并分析上述药物不同耐药性组合下其它抗生素耐药性情况。结果七年共检出铜绿假单胞菌1920株,其中多黏菌素耐药率最低为1%;阿米卡星、庆大霉素、妥布霉素平均耐药率分别为6.4%,8.6%,5.1%;喹诺酮类与哌拉西林/他唑巴坦、头孢他啶、头孢吡肟耐药率相似,在10%~20%之间;亚胺培南和美罗培南未显示出更优秀的敏感性,耐药率分别为21.3%和18.4%。各主要抗生素耐药率在七年间存在波动,多数自2017年上升,至2018年达峰值后回落,2020年后趋于平稳并与国内平均水平一致;亚胺培南敏感株1393株,该部分美罗培南敏感率为96.2%;美罗培南敏感株1451株,该部分亚胺培南敏感率为89%。亚胺培南、美罗培南均耐药共369株,该部分头孢他啶敏感率为33.1%。β-内酰胺类抗生素耐药种类越多,阿米卡星、环丙沙星敏感率越低。结论该院铜绿假单胞菌药物敏感性总体较好,应坚持严格的抗生素使用管理。氨基糖苷类可作为经验治疗首选药物,喹诺酮类次之,碳青霉烯类和头孢他啶亦为备选。该院铜绿假单胞菌对β-内酰胺类抗生素耐药机制呈多样性,碳青霉烯耐药株可由不同机制分别或共同介导。

甘肃省成年居民婚姻状况与腰椎间盘突出症的关联研究

目的了解甘肃省成年居民婚姻状况与腰椎间盘突出症的关系。方法于2022年5月—2022年7月在甘肃省根据海拔(≥3500 m、1500~3500 m、<1500 m)进行分层整群抽样,共调查4598人。对所有研究对象进行问卷调查、体格检查、血糖血脂检测。采用单因素分析与非条件二元Logistic回归模型分析婚姻状况与腰椎间盘突出症的关联性。结果本次调查最终有效样本为4545例。有配偶者腰椎间盘突出症患病率为24.49%,高于无配偶者,差异有统计学意义(P<0.05);在有配偶者中,腰椎间盘突出症患病率女性高于男性,<45岁年龄段高于其他年龄段,藏族高于其他民族,差异均有统计学意义(P<0.05)。二元Logistic回归分析结果显示,有配偶者中女性、年龄≥45岁、农林牧渔、工人、其他职业、居住海拔≥1500 m,高血压均为腰椎间盘突出症的危险因素(OR>1)。结论甘肃省成年居民有无配偶状态与腰椎间盘突出症患病存在关联,且有配偶者患病率相对较高。

双极化复用信号的接收技术研究

针对双极化复用传输系统的交叉极化干扰问题,提出一种适用于双极化复用信号的接收技术。在接收链路本振不同源的情况下,参考信号与干扰信号载波频率不同,干扰不能被对消。从理论上推导了参考信号与干扰信号之间的频率关系,并通过频率补偿模块消除参考信号与干扰信号间的频差,使得参考信号与干扰信号频率一致,从而实现极化干扰对消。测试结果表明,链路本振不同源的情况下,该方法可有效减少交叉极化干扰带来的误码率恶化。

人民币汇率升值、贸易开放水平与跨境人民币结算

本文基于2011—2021年我国省级平衡面板数据,使用pvar模型研究跨境人民币结算金额、人民币汇率及贸易开放三者之间的动态关系。结果表明:保持一定规模的贸易开放及稳中有升的人民币币值会助推跨境人民币结算规模的扩大,进而推进人民币国际化进程。基于此,本文就进一步发挥稳定的对外开放水平和稳中有升的人民币币值对跨境人民币结算的促进作用提出相关政策建议,以供参考。

挪威红牛改良荷斯坦奶牛的妊娠率分析

[目的]研究现存混养的条件下挪威红牛配种荷斯坦奶牛后的妊娠优势,以提高荷斯坦奶牛的繁殖力。[方法]以荷斯坦奶牛作为母本,进口挪威红牛冻精为父本,进行杂交改良(挪威红牛♂×荷斯坦奶牛♀),培育杂种牛,统计不同月份、不同年龄段的配种数、妊娠数、妊娠率。[结果]杂交种牛相比于荷斯坦牛,自然发情配种的妊娠率提高36.41百分点;同期处理配种,妊娠率提高30.24百分点;青年牛配种,妊娠率提高47.64百分点;群体年度配种,妊娠率提高了36.83百分点,杂交牛场配种妊娠率显著高于荷斯坦牛场。[结论]杂交牛场经过挪威红牛乳肉兼用型牛的品种改良,明显提高了牛场群体繁育率。