基于ISM模型的邮轮航线要素分析及优化研究

在全球经济增长乏力的情况下,我国邮轮产业方兴未艾,围绕着南海开发,中国—东盟合作前景一片广阔。本文以粤港澳大湾区为邮轮母港出发地,以邮轮航线优化要素为影响因子,建立要素解释结构模型,分析邮轮航线要素对优化方案的重要性程度,以及各个要素之间的影响关系。

基于ISM-MICMAC的服装生产线平衡优化

面对消费者选购服装时的个性化需求,服装制造企业需要设置不同的生产线,以此提高产品的市场占有率,但是生产线增多,服装生产线中带来的问题也随之增多。本文以HC公司为切入点,首先利用解释结构模型(ISM)去分析导致生产线不平衡的因素之间的关系,使用MICMAC模型对解释结构模型进行验证,最终根据模型的结果提出一些建议,也给其他面临相同问题的企业带来一些参考。

Radio Interference Characteristic of Ultra-high Voltage AC Transmission Lines by Using Stochastic Modeling

For developing ultra-high voltage(UHV) AC power transmission systems,it is important to precisely estimate and to limit the radio interference(RI) level of power lines.Based on the stochastic characteristics in amplitude and repetition rate of induced corona current,by using the probability theory and mathematical statistics,we establish a stochastic model for the wide-sense stationary random process of corona discharges.Then combining the stochastic model with model-propagation-analysis method,the RI levels under three-phase UHV AC transmission lines are calculated.The results of the calculation based on stochastic model method and International Council on Large Electric Systems(CIGRE) excitation function are compared with that based on semi-empirical method and some other excitation functions.The stochastic model based on different excitation functions is also adopted to simulate the RI levels under finite test lines with two opened terminations.The results indicate that with the same average maximum gradient on conductor surface and the same conductor type,the number of corona discharge per unit length is one of the main reasons that causes the difference between different excitation functions.It is also concluded that for a long test line,the effect of standing wave on RI field strength is negligible in the middle of the line,but obvious near both terminations: for a 10-km line,the maximum difference in RI field strength is 2.78 dB,between the peak value of the standing wave near the ends and the steady value near the middle of the line.

电离氢区S187的大尺度CO多谱线观测

大质量恒星强烈的反馈深刻影响其周围的星际介质,并可能触发下一代恒星形成.S187是位于银河系第2象限的大质量恒星形成区,呈现出“扫集-坍缩”的触发式恒星形成模式.基于“银河画卷”巡天^(12)CO/^(13)CO/C^(18)O(J=1-0,下文J=1-0为简便起见省略)谱线数据,对S187区域分子云的基本性质开展了研究,探索了该区域大质量恒星对分子云的反馈.利用GaussPy+和聚类算法,在该区域证认了32个分子云,并结合Gaia(Global Astrometric Interferometer for Astrophysics)卫星恒星消光数据测量得到其中8个分子云的距离.S187区域由^(13)CO和C^(18)O示踪的相对致密的气体含量相比于银道面第2象限大部分区域的分子云高出1–2个量级.S187区域分子云中证认了243个^(13)CO团块和98个C^(18)O团块,其中有7个^(13)CO团块和5个C^(18)O团块有形成大质量恒星的潜力.研究结果显示,大质量恒星的反馈对其周围分子云的聚集作用明显,为下一代大质量恒星的形成提供了条件.

基于FPGA的射频腔体系统数学模型在线辨识算法

射频系统的数学模型包含了射频腔体的关键特征参数(如腔体半带宽、谐振频率和洛伦兹力失谐系数等),数学模型对腔体性能检测、控制系统仿真及低电平控制算法优化具有重要意义。网络分析仪通常用于测量射频系统的散射参数,进而构建射频系统的数学模型,但其测量步骤繁琐且无法实现系统模型的在线自动辨识。本文通过模拟网络分析仪的工作原理,在数字低电平系统内部构建了基于数控振荡器的扫频算法,实现了射频腔体系统的在线辨识。该算法的有效性已在加速器驱动嬗变研究装置前端示范样机的超导腔上验证,其测量结果与网络分析仪测量结果吻合。此外,本文利用该辨识算法还成功测得了由洛伦兹力失谐引起的超导腔频率响应畸变曲线,并讨论了洛伦兹力失谐量的大小对腔体关键特征参数测量的影响。

HI in High Gas-phase Metallicity Dwarf Galaxy WISEA J230615.06+143927.9

We present resolved Giant Metrewave Radio Telescope H I observations of the high gas-phase metallicity dwarf galaxy WISEA J230615.06+143927.9(z = 0.005)(hereafter J2306) and investigate whether it could be a Tidal Dwarf Galaxy(TDG) candidate. TDGs are observed to have higher metallicities than normal dwarfs. J2306 has an unusual combination of a blue g-r color of 0.23 mag, irregular optical morphology and high-metallicity(12 +log(O/H) = 8.68 ± 0.14), making it an interesting galaxy to study in more detail. We find J2306 to be an H I rich galaxy with a large extended, unperturbed rotating H I disk. Using our H I data we estimated its dynamical mass and found the galaxy to be dark matter(DM) dominated within its H I radius. The quantity of DM, inferred from its dynamical mass, appears to rule out J2306 as an evolved TDG. A wide area environment search reveals J2306 to be isolated from any larger galaxies which could have been the source of its high gas metallicity. Additionally, the H I morphology and kinematics of the galaxy show no indication of a recent merger to explain the high-metallicity.Further detailed optical spectroscopic observations of J2306 might provide an answer to how a seemingly ordinary irregular dwarf galaxy achieved such a high level of metal enrichment.

面向环境射频能量收集的宽频整流电路

整流电路是射频能量回收系统的核心,能够将射频能量转换为直流。但由于整流电路中使用的二极管具有非线性特性,导致整流效率会随频率变化而降低。为解决这一问题,本文提出一种具有宽频带的整流电路,它通过采用与二极管串联的短路线、与二极管并联的开路线以及多级微带线结构来调整阻抗匹配,实现了在宽频带范围内的高转换效率。设计的整流电路在0 dBm的输入功率下,从1.7~2.7 GHz,均达到50%的整流转换效率,最高整流转换效率为63.3%。该宽带整流电路可以运用在无线能量收集系统中。

基于复合左右手理论的双模态低损耗宽带毫米波片上传输线

本文提出了一种基于复合左右手(Composite Right-/Left-Handed,CRLH)理论的双模态毫米波片上传输线(Transmission Line,TL),有效兼顾了宽频段和低损耗特性,并且同时包含支持前向波的右手频段和支持后向波的左手频段.为解决毫米波半导体衬底高损耗、高寄生干扰的问题,本文首先提出T型片上CRLH单元,通过研究CRLH传输线的电路拓扑与结构实现,减小了传输损耗并展宽带宽.此外,文章通过研究色散特性实现左手和右手通带两种模态.基于砷化镓(GaAs)基集成无源器件(Integrated Passive Device,IPD)工艺,加工并实测了一款工作频段覆盖18~44.5 GHz的3阶周期CRLH TL.本文提出的传输线尺寸紧凑,为1.3 mm×0.55 mm,带有GSG(Ground Signal Ground)焊盘,最小插入损耗为1.18 dB,3 dB相对带宽超过90%.该测试结果表明所提出的片上传输线可广泛应用于实现独特电磁相位特性的片上功能电路和系统.

Molecular Oxygen Abundance in Galactic Massive Star Formation Regions Based on SWAS Observations

Molecular oxygen abundance is a key parameter in understanding the chemical network of the interstellar medium.We estimate the molecular oxygen column density and abundance for a sample of Galactic massive star formation regions based on observations from the Submillimiter Wave Astronomy Satellite(SWAS)survey.We obtained an averaged O_(2)spectrum based on this sample using the(SWAS)survey data(O_(2),487.249 GHz,N=3-1,J=3-2).No emission or absorption feature is seen around the supposed central velocity with a total integration time of t_(total)=8.67×10^(3)hr and an rms noise per channel of 1.45 m K.Assuming a kinetic temperature T_(kin)=30 K,we derive the 3σupper limit of the O_(2)column density to be 3.3×10^(15)cm^(-2),close to the lowest values reported in Galactic massive star formation regions in previous studies.The corresponding O_(2)abundance upper limit is6.7×10^(-8),lower than all previous results based on SWAS observations and is close to the lowest reported value in massive star formation regions.On a galactic scale,our statistical results confirm a generally low O_(2)abundance for Galactic massive star formation regions.This abundance is also lower than results reported in extragalactic sources.

Observation of HⅠaround three Satellite Galaxies of M31 with FAST:AndromedaⅡ,NGC 205,and NGC 185

With the exceptional sensitivity of the Five-hundred-meter Aperture Spherical radio Telescope,we conducted observations of the neutral hydrogen(HⅠ)in the circumgalactic medium of Andromeda’s(M31)satellite galaxies,specifically AndromedaⅡ,NGC 205,and NGC 185.Initially,three drift scans were executed for these satellites,with a detection limit of 4×10^(18)cm^(-2)(approximately 1.88×10^(3)M_Θof HⅠmass),followed by a more in-depth scan of a specific region.We discovered a C-shaped HⅠarc structure sharing a position and line-of-sight velocity similar to a stellar ring structure around AndromedaⅡ,hinting at a potential connection with AndromedaⅡ.In the context of NGC 205,we identified two mass concentrations in the northeast direction,which could be indicative of tidal streams resulting from the interaction between this galaxy and M31.These new lumps discovered could be very helpful in solving the missing interstellar medium problem for NGC 205.Observations regarding NGC 185are consistent with previous studies,and we did not detect any additional HⅠmaterial around this galaxy.These observational results enhance our understanding of the evolution of these satellite galaxies and provide insight into their historical interactions with the galaxy M31.

FAST Observations of Four Comets to Search for the Molecular Line Emissions between 1.0 and 1.5 GHz Frequencies

We used the Five-hundred-meter Aperture Spherical radio Telescope(FAST)to search for the molecular emissions in the L-band between 1.0 and 1.5 GHz toward four comets,C/2020 F3(NEOWISE),C/2020 R4(ATLAS),C/2021 A1(Leonard),and 67P/Churyumov-Gerasimenko during or after their perihelion passages.Thousands of molecular transition lines fall in this low-frequency range,many attributed to complex organic or prebiotic molecules.We conducted a blind search for the possible molecular lines in this frequency range in those comets and could not identify clear signals of molecular emissions in the data.Although several molecules have been detected at high frequencies of greater than100 GHz in comets,our results confirm that it is challenging to detect molecular transitions in the L-band frequency ranges.The non-detection of L-band molecular lines in the cometary environment could rule out the possibility of unusually strong lines,which could be caused by the masers or non-LTE effects.Although the line strengths are predicted to be weak,for FAST,using the ultra-wide bandwidth receiver and improving the radio frequency interference environments would enhance the detectability of those molecular transitions at low frequencies in the future.

Long-term Integration Ability of the Submillimeter Wave Astronomy Satellite(SWAS)Spectral Line Receivers

The Submillimeter Wave Astronomy Satellite(SWAS)was the first space telescope capable of high spectral resolution observations of terahertz spectral lines.We have investigated the integration ability of its two receivers and spectrometer during five and a half years of on-orbit operation.The CI,O_(2),H_(2)O,and^(13)CO spectra taken toward all observed Galactic sources were analyzed.The present results are based on spectra with a total integration time of up to 2.72×10~4hr(■10~8s).The noise in the spectra is generally consistent with that expected from the radiometer equation,without any sign of approaching a noise floor.This noise performance reflects the extremely stable performance of the passively cooled front end as well as other relevant components in the SWAS instrument throughout its mission lifetime.

Summary of a Life in Observational Ultraviolet/Optical Astronomy

I reminisce on my early life in Section 1;on my education in Sections 2 and 3;on the years at Princeton as a research astronomer in Section 4;on the years on the faculty at Chicago in Section 5;on research on Diffuse Interstellar Bands(DIBs) in Section 6;on construction of the 3.5 m telescope at Apache Point Observatory(APO)in Section 7;on work on the Sloan Digital Sky Survey(SDSS) in Section 8;on work in public education in Chicago in Section 9;and on my travels in Section 10. My main science research is of an observational nature,concerning Galactic and intergalactic interstellar gas. Highlights for me included my work on the orbiting telescope Copernicus, including the discovery of interstellar deuterium;early observations of absorption associated with fivetimes ionized oxygen;and discoveries concerning the phases of gas in the local interstellar medium, based on previously unobservable interstellar UV spectral lines. With other instruments and collaborations, I extended interstellar UV studies to the intergalactic cool gas using quasi-stellar object QSO absorption lines redshifted to the optical part of the spectrum;provided a better definition of the emission and morphological character of the source of absorption lines in QSO spectra;and pursued the identification of the unidentified DIBs. For several of these topics, extensive collaborations with many scientists were essential over many years. The conclusions developed slowly, as I moved from being a graduate student at Chicago, to a research scientist position at Princeton and then to a faculty position at Chicago. At each stage of life, I was exposed to new technologies adaptable to my science and to subsequent projects. From high school days, I encountered several management opportunities which were formative. I have been extremely fortunate both in scientific mentors I had and in experimental opportunities I encountered.

城市高压交流输电线路对电磁环境的影响研究

电磁环境承载无线电通信、广播和观测等业务,支撑移动互联网、物联网、卫星电视和射电望远镜等新型基础设施,保护电磁环境成为交流输变电系统设计运行的关键。该研究选取城市常见的架空220 kV交流输电线路为研究对象,测量某线路附近地面及居民楼内电场和磁场强度,分析电磁干扰的来源、产生机理、频域特征和空间衰减过程,比照城市常见无线电业务的频段和调制方式,得到典型工况下输电线路对无线电信号信噪比的影响规律,提出输电系统影响下,电磁环境保护和通信增益措施。

基于GPRS技术的输电线路状态数据通信系统设计

在现代电力系统管理中,实时监测输电线路的状态至关重要,这不仅有助于提前预防故障,而且能优化能源分配和增强系统的可靠性。通用分组无线业务(General Packet Radio Service,GPRS)技术作为一种成熟的无线数据传输手段,为远程输电线路监测提供了一种有效的通信解决方案。文章设计基于GPRS技术的输电线路状态数据通信系统,重点分析系统的总体架构、GPRS通信模块的设计、数据管理与传输策略以及安全性与容错机制的构建,并阐述测试系统的方法及其效果。

基于接地线电流法的电力电缆绝缘在线监测

为提高电力系统的安全性,将接地线电流法作为核心方法,设计电力电缆绝缘在线监测系统。采用通用分组无线业务/码分多址(General Packet Radio Service/Code Division Multiple Access,GPRS/CDMA)通信方式作为电力电缆绝缘在线监测系统的核心,建立电缆各条线路之间的通信连接。利用电流互感器(Current Transformer,CT)检测电缆电流变化情况,有利于提高绝缘在线监测系统的检测精度。将绝缘在线监测应用于电力系统,可为电力系统的后续发展提供依据。

基于STAMP-ISM的地铁事故分析方法研究

作为城市轨道交通的重要支柱之一,地铁已经成为现代城市生活中不可缺少的一部分。一旦地铁运营发生事故,不仅会带来巨大的经济损失,也会威胁到人民的生命安全。本文将STAMP模型与三角模糊DEMATEL-ISM模型相结合,以更加深入地分析地铁运营事故,对地铁事故影响因素进行等级划分,绘制地铁事故影响因素多级阶梯图,深入剖析地铁事故因素之间的逻辑关系,从而有针对性地提出地铁事故的预防措施。以上海地铁10号线列车追尾事故为案例进行分析,结果表明:STAMP模型与三角模糊DEMATEL-ISM模型的结合解决了传统STAMP模型无法突出重点的缺陷,也解决了传统ISM模型对二因素影响关系分类的局限性,可以更加全面深入地分析该事故各致因因素间的影响结果,从而有针对性地预防事故的发生。

Extragalactic dispersion measures of fast radio bursts

Fast radio bursts show large dispersion measures, much larger than the Galactic dispersion measure foreground. Therefore, they evidently have an extragalac- tic origin. We investigate possible contributions to the dispersion measure from host galaxies. We simulate the spatial distribution of fast radio bursts and calculate the dis- persion measures along the sightlines from fast radio bursts to the edge of host galaxies by using the scaled NE2001 model for thermal electron density distributions. We find that contributions to the dispersion measure of fast radio bursts from the host galaxy follow a skew Gaussian distribution. The peak and the width at half maximum of the dispersion measure distribution increase with the inclination angle of a spiral galaxy, to large values when the inclination angle is over 70~. The largest dispersion measure produced by an edge-on spiral galaxy can reach a few thousand pc cm-3, while the dispersion measures from dwarf galaxies and elliptical galaxies have a maximum of only a few tens of pc cm-3. Notice, however, that additional dispersion measures of tens to hundreds of pc cm-3 can be produced by high density clumps in host galaxies. Simulations that include dispersion measure contributions from the Large Magellanic Cloud and the Andromeda Galaxy are shown as examples to demonstrate how to ex- tract the dispersion measure from the intergalactic medium.

能量检测法在ISM 2.4GHz频段通信系统共存中的应用

针对频谱检测技术,对比了三种常见的检测方法,通过建立数学模型和数学分析,提出了一种改进型能量检测法。该方法采用了一种新的平均判决量,相对于经典的能量输出判决量,该平均判决量对ISM 2.4GHz复杂的噪声信号有较强的鲁棒性,最后用MATLAB仿真实验证明了该方法的有效性。

Balmer H_α,H_β and H_γ Spectral Lines Intensities in High-Power RF Hydrogen Plasmas

Hα（Balmer-alpha）, Hβ （Balmer-beta） and Hγ （Balmer-gamma） spectral line inten- sities in atomic hydrogen plasma are investigated by using a high-power RF source. The intensities of the Hα, Hβ and Hγ spectral lines are detected by increasing the input power （0-6 kW） of ICPs （inductively coupled plasmas）. With the increase of net input power, the intensity of Hα im- proves rapidly （0-2 kW）, and then reaches its dynamic equilibrium; the intensities of Hβ can be divided into three processes： obvious increase （0-2 kW）, rapid increase （2-4 kW）, almost constant （4-6 kW）; while the intensities of Hγ increase very slowly. The energy levels of the excited hydro- gen atoms and the splitting energy levels produced by an obvious Stark effect play an important role in the results.