城市低碳转型背景下绿色交通内涵解析与发展路径

发展绿色交通是贯彻落实生态文明思想和国家绿色发展战略、实现“双碳”目标、促进城市交通系统可持续发展、引导城市低碳转型的关键举措。针对当前绿色交通实践工作主要聚焦于交通工具或交通设施的局限性,提出绿色交通的内涵是基于以人为本、高质量和可持续发展理念,以追求低能耗、低排放为核心目标,同时满足交通与城市发展协调、交通运输效率和效益改善以及人民群众出行品质提升的发展新范式。基于全生命周期、全要素系统发展路径,从交通运输节能降碳、高品质服务人的需求和塑造低耗城市空间形态3个方面提出发展绿色交通的措施建议,助力城市加快实现“双碳”目标。

玉米黄色素微胶囊在风味发酵乳中的应用

本文使用超声辅助麦芽糊精(Malto Dextrin,MD)制备玉米黄色素(Maize Yellow Pigment,MYP)微胶囊,以提高MYP的溶解度和稳定性,对其进行了结构表征、理化测定和性能测定,并将其应用于风味发酵乳。扫描电镜和傅里叶变换红外结果证实了微胶囊的形成,粒径和电位结果证明了微胶囊为纳米级且稳定,热重结果表明微胶囊提高了MYP的热稳定性;最优条件下微胶囊中的包埋率为33.51%;微胶囊的溶解度、稳定性明显提高,微胶囊的抗氧化活性随着MYP的增加而增强,微胶囊生物利用度明显提高(P<0.01);样品组与对照组酸奶相比,分析的理化指标未显示显著差异(p>0.05)。本文研究表明所制备的MYP微胶囊可以增强MYP的溶解性、稳定性和缓释性,可以用作酸奶中的着色剂和抗氧化剂。

Achieving high-efficient photocatalytic persulfate-activated degradation of tetracycline via carbon dots modified MIL-101(Fe)octahedrons

The synergistic reaction of photocatalysis and advanced oxidation is a valid strategy for the degradation of harmful antibiotic wastewater.Herein,carbon dots(CDs)modified MIL-101(Fe)octahedrons to form CDs/MIL-101(Fe)composite photocatalyst was synthesized for visible light-driven photocatalytic/persulfate(PS)-activated tetracycline(TC)degradation.The electron spin resonance(ESR)spectra,scavenging experiment and electrochemical analysis were carried out to reveal that the high visible light-driven photocatalytic degradation activity of TC over CDs/MIL-101(Fe)photocatalysts is not only ascribed to the production of free active radicals in the CDs/MIL-101(Fe)/PS system(·OH,·SO_(4-),^(1)O_(2),h^(+)and·O_(2)^(-))but also attributed to the consumption of electrons caused by the PS,which can suppress the recombination of photo-generated carriers as well as strong light scattering and electron trapping effects of CDs.Finally,the possible degradation pathways were proposed by analyzing intermediates via liquid chromatography-mass spectrometry technique.This research presents a rational design conception to construct a CDs/PS-based photocatalysis/advanced oxidation technology with high-efficient degradation activity for the remediation of organic antibiotic pollutant wastewater and for the improvement of carrier transport kinetics of photocatalysts.

Time-resolved characteristics of a nanosecond pulsed multi-hollow needle plate packed bed dielectric barrier discharge

In this paper,self-designed multi-hollow needle electrodes are used as a high-voltage electrode in a packed bed dielectric barrier discharge reactor to facilitate fast gas flow through the active discharge area and achieve large-volume stable discharge.The dynamic characteristics of the plasma,the generated active species,and the energy transfer mechanisms in both positive discharge(PD)and negative discharge(ND)are investigated by using fast-exposure intensified charge coupled device(ICCD)images and time-resolved optical emission spectra.The experimental results show that the discharge intensity,number of discharge channels,and discharge volume are obviously enhanced when the multi-needle electrode is replaced by a multihollow needle electrode.During a single voltage pulse period,PD mainly develops in a streamer mode,which results in a stronger discharge current,luminous intensity,and E/N compared with the diffuse mode observed in ND.In PD,as the gap between dielectric beads changes from 0 to250μm,the discharge between the dielectric bead gap changes from a partial discharge to a standing filamentary micro-discharge,which allows the plasma to leave the local area and is conducive to the propagation of surface streamers.In ND,the discharge only appears as a diffusionlike mode between the gap of dielectric beads,regardless of whether there is a discharge gap.Moreover,the generation of excited states N_(2)^(+)(B^(2)∑_(u)^(+))and N2(C^(3)Π_(u))is mainly observed in PD,which is attributed to the higher E/N in PD than that in ND.However,the generation of the OH(A^(2)∑^(+))radical in ND is higher than in PD.It is not directly dominated by E/N,but mainly by the resonant energy transfer process between metastable N_(2)(A^(3)∑_(u)^(+))and OH(X^(2)Π).Furthermore,both PD and ND demonstrate obvious energy relaxation processes of electron-to-vibration and vibration-to-vibration,and no vibration-to-rotation energy relaxation process is observed.

面向城市管理平台的道路网韧性评价指标体系构建

研究异常事件(灾害)情况下道路网退化阶段和恢复阶段的性能,有助于制定针对性的应急处置措施,将灾害对道路网的影响降到最低,从而提升城市道路网韧性。首先,解析道路网韧性评价理论,即道路网韧性与异常事件特征、道路网自身的抗毁性能以及干预措施的施加时间和力度有关,并分析了异常事件类型及损坏特征,明确了道路网抗毁性能相关因素。其次,提出道路网韧性评价“两类三级”指标体系及计算方法,两类包括灾前抗毁性能评价和灾后恢复性能评价。前者旨在通过风险预判和模拟试算了解城市道路网吸收扰动的能力;后者旨在实时评价灾后各阶段道路网的使用性能,指导恢复阶段的施力方向。最后,针对不同异常事件类型和应用场景给出指标选取建议,并展示部分指标计算案例。

Worst-case tolerance analysis on array antenna based on chaos-genetic algorithm

This paper studies the effect of amplitude-phase errors on the antenna performance. Via builting on a worst-case error tolerance model, a simple and practical worst error tolerance analysis based on the chaos-genetic algorithm （CGA） is proposed. The proposed method utilizes chaos to optimize initial population for the genetic algorithm （GA） and introduces chaotic disturbance into the genetic mutation, thereby improving the ability of the GA to search for the global optimum. Numerical simulations demonstrate that the accuracy and stability of the worst-case analysis of the proposed approach are superior to the GA. And the proposed algorithm can be used easily for the error tolerant design of antenna arrays.

干眼角膜上皮损伤患者患病率和危险因素的回顾性研究

目的:探究干眼角膜上皮损伤患者的流行病学特征及相关危险因素。方法:回顾2018-07/2019-06期间就诊于北京大学第三医院的干眼角膜上皮损伤患者的门诊病历,对患者性别、年龄、就诊日期、合并症以及同一时期的气象指标进行统计学分析。结果:回顾性分析291名干眼角膜上皮损伤患者,其中有75.3%为女性。21-30岁的青年患者占比最大(26.5%),青少年(<18岁,5.8%)和老年人(≥61岁,17.2%)较少。然而,中青年患者虽然占比较大,其平均就诊次数较少(5.4±12.4)。春季和冬季是最主要的就诊季节。分析表明,PM_(10)、二氧化硫(SO_(2))、二氧化氮(NO_(2))、以及较低的平均相对湿度与干眼角膜上皮损伤显著相关(P<0.05)。结膜炎、白内障、视物模糊以及倒睫是排名前四位的合并症。结论:女性、青年人群干眼角膜上皮损伤问题不容忽视。PM_(10)、SO_(2)、NO_(2)和空气湿度降低与干眼角膜上皮损伤显著相关。对于合并有结膜炎、白内障、视物模糊以及倒睫的干眼患者,更应关注其角膜状况。

An Improved RPL Algorithm for Low-Power and Lossy Networks

The routing protocol for low-power and lossy networks(RPL),standardized by Internet Engineering Task Force(IETF),is mainly designed to use for Low-power and Lossy Networks(LLNs).To solve the problems of several important routing metrics are not evaluated,the optimal path may contain long single hop links,lack of scientific multi-routing metrics evaluation method and mechanism to balance the parent child number(especially the parent with one hop away from root),this paper proposes an improved RPL algorithm for LLN(I-RPL).First of all,we propose the evaluated routing metrics:child number of parent,candidate parent number,hop count,ETX and energy consumption index.Meanwhile,we improve the path ETX calculation method to avoid selecting optimal path containing long single hop links.Then we design a novel lexical method to synthetically evaluate candidate parents.Meanwhile,based on the evaluation results of candidate parents,we design a novel objective function and a new calculation node rank method which can also be used for selecting the optimal path.Finally,evaluation results show that I-RPL outperforms ETXOF and several other improvements in terms of packet delivery ratio,latency,etc.

Generation of atmospheric pressure air diffuse discharge plasma in oxygen enriched working gas with floating electrode

In this work,a floating electrode is employed to generate a stable large-area diffuse discharge plasma under an open oxygen-rich environment.The discharge image and the optical emission spectra of the N2(C-B),N2+(B-X),N2(B-A),and O(3p–3s,777 nm)are measured to analyze the morphological and optical characteristics of the discharge.The effects of applied voltage,gas flow rate,and electrode gap on the reactive species,vibrational temperature and rotational temperature are investigated,and the discharge mode is discussed by simulating the electrostatic field before the breakdown.It is found that the changes of applied voltage and electrode gap causes the transition of the discharge modes among corona mode,diffuse discharge mode and spark mode.It is shown that the floating electrode can inhibit the transition from discharge to spark mode to a certain extent,which is conducive to maintaining the stability of discharge.As is vividly illustrated in this study,the increase of applied voltage or the decrease of electrode gap contributes to the generation of more active particles,such as N2(C)andN+2(B).Furthermore,the Joule heating effect becomes more evident with the increased applied voltage when the electrode gap is 15 and 20 mm.Moreover,as the applied voltage increases,the vibrational temperature increases at the electrode gap of 25 mm.

微波协同磁性NiFe_(2)O_(4)活化过硫酸盐降解盐酸四环素的研究

研究采用水热法成功制备了磁性铁酸镍(NiFe_(2)O_(4)),并利用X射线衍射(XRD)等对磁性NiFe_(2)O_(4)的性质进行表征。在微波作用(MW)和过硫酸盐(PS)存在下,系统地开展了MW与磁性NiFe_(2)O_(4)活化过硫酸盐对水溶液中盐酸四环素(TCH)氧化反应过程的影响因素及反应机制研究。结果表明:MW和磁性NiFe_(2)O_(4)协同活化过硫酸盐体系对TCH的去除率较好,在最佳条件反应下,去除率可达到88.8%。此外,通过对pH、过硫酸盐浓度、催化剂剂量等影响因素对TCH降解效果的研究显示,磁性NiFe_(2)O_(4)可有效活化过硫酸盐,在抗生素废水处理中具有潜在的应用前景。

Dexmedetomidine-induced anesthesia in elderly patients undergoing hip replacement surgery

BACKGROUND A femoral neck fracture is a common and frequently reported issue in orthopedics, with a greater rate of incidence among the elderly. Due to their advanced age and the presence of some primary diseases, both anesthesia and surgery are increasingly difficult in elderly patients with a femoral neck fractures. In fact,general anesthesia can easily induce complications such as cognitive dysfunction,which is not conducive to postoperative recovery.AIM To analyze the efficacy of dexmedetomidine in inducing anesthesia for elderly patients undergoing hip replacement surgery.METHODS A total of 98 elderly patients undergoing hip replacement in our hospital from June 2020 to June 2021 were randomly divided into control group(49 cases) and observation group(49 cases). The control group was given general anesthesia, and the observation group was combined with dexmedetomidine for anesthesia on the basis of the control group. Both groups were observed until the patients were discharged. The vital signs, serum inflammatory factors and renal function indexes of the two groups were compared before, during and 6 h after operation.The postoperative recovery and adverse events of the two groups were statistically analyzed.RESULTS Compared with the mean arterial pressure of the two groups, the intraoperative and postoperative 6 h was higher than that before the operation, the intraoperative was lower than the postoperative 6 h(P < 0.05);the blood oxygen saturation of the two groups was higher than that before operation and 6 h after operation, and the observation group was higher than the control group 6 h after operation(P < 0.05). The heart rate of the two groups was lower during and 6 h after operation than that before operation, and higher at 6 h after operation than that during operation(P < 0.05).The levels of serum C-reactive protein, tumor necrosis factor-α, interleukin-1β and kidney injury molecule-1 in the two groups were higher during operation and 6 h after operation than those before operation(P < 0.05). The level of serum urea nitrogen in the two groups was higher than that before operation, and that in the observation group was lower than that in the control group(P < 0.05). During hospitalization, the first time of getting out of bed, recovery time of grade Ⅱ muscle strength, recovery time of grade Ⅲ muscle strength and hospitalization time in the observation group were shorter than those in the control group(P < 0.05).CONCLUSION Dexmedetomidine can effectively improve the vital signs of elderly patients undergoing hip replacement surgery, reduce the body’s inflammatory response and renal function damage, and promote postoperative recovery. Meanwhile, dexmedetomidine showcased a good safety profile and a good anesthetic outcome.

A novel modification method for the dynamic mechanical test using thermomechanical analyzer for composite multi-layered energetic materials

Herein,we present a thermo-mechanical analyzer(TMA)and dynamic mechanical analyzer(DMA)of composite multi-layered gun propellant,focusing on thermal expansion coefficients and dynamic thermomechanical properties.The linear thermal expansion coefficient of the prepared energetic material is determined as approx.0.1800×10^(-4)-0.2081×10^(-4)K^(-1).According to DMA test and dynamic thermomechanical properties,the glass transition temperature is also obtained.The tested value is within the range of 223.01-223.50 K,which indicates the lower limit of the energetic material.However,DMA tests reveal temperature changes,which occur due to thermal expansion.Moreover,the geometrical factor decreases with increasing temperature.Therefore,thermal expansion significantly affects the storage modulus and loss modulus.Additionally,the thermal expansion coefficient can be used to modify the storage and loss modulus.The results show that the proposed method provides effective and reliable modified results.

包头地区汉族人群ESRα基因rs9340799多态性与男性不育的相关性

目的:探讨内蒙古包头地区ESRα基因单核苷酸多态性rs9340799与汉族人群男性不育的关系。方法:选取少弱精病例组和正常对照组各200例样本,采用PCR-RFLP法对ESRα基因rs9340799位点进行基因型分型,并采用二元Logistic回归分析rs9340799多态性与男性不育的关系,同时设计收集男性健康调查问卷和临床流行病学资料。结果:ESRα基因SNP rs9340799在显性和共显性遗传模型中与男性不育患病风险均相关(P<0.05);两组研究对象的基因型和等位基因频率分布差异有统计学意义,携带G等位基因与男性不育疾病的患病风险降低相关(OR=0.198,95%CI:0.119-0.330);另有精液分析结果得出少弱精病例组和对照组的年龄、前向运动精子、非前向运动精子、精子总浓度和精子总活力差异均有统计学意义(P<0.05),问卷资料统计得出两组研究对象的室内外工作环境和家庭地板装修情况存在差异。结论:ESRα基因单核苷酸多态性rs9340799可能与内蒙古包头地区汉族人群男性不育患病风险相关。

基于认知契合理论的移动购书类应用设计研究

探索认知契合理论在移动购书设计中的应用,以设计出更精准的移动购书界面,提升用户体验,为移动购书类应用设计开发提供参考依据。首先分析认知契合理论应用于移动购书类应用的技术可行性和具体方法,其次通过调研分析用户需求,以此提炼移动购书中三类用户内部表征特点,最后基于认知契合,提出基于三类内部表征的移动购书设计策略。借助认知契合理论分析得出,移动购书用户的购物动机、购买前信息搜寻行为和购物价值特征,提出动机提升策略、行为引导策略和价值导向策略。认知契合理论的运用能够帮助设计和开发者了解用户内部特征,设计契合用户行为和价值的策略。

国土空间规划背景下我国交通规划转型思考

为应对国土空间规划转型,推动交通高质量发展,从国土空间与交通互动视角研究了我国交通发展面临的问题、趋势与对策。首先,从国土开放、国土开发、生态文明、人的美好生活等国土空间视角,分析了当前我国交通发展面临的问题,并从“两头在外”的外向型经济特征、连通度导向的交通设施布局、不完善的空间规划体系、工业化时代相对单一的价值观等方面剖析了成因。然后,从资源环境紧约束、国土开放开发格局、人口和国民生活方式变化等方面,研判了未来空间发展对交通发展要求的变化。最后,从三方面提出了我国交通规划转型的思考:建立基于资源环境承载力的国家交通发展理念,构建质量和效率导向的国家交通格局,构建多元包容的高品质交通体系。

长江经济带战略背景下长江上游港口群发展

水运是长江上游省份进出口贸易和地区间物资运输的重要方式。首先,论述了长江上游内河航运地位的变迁和未来发展态势。改革开放以后长江作为东西向物流运输大通道的功能逐渐发挥,未来上游地区的江海联运仍然具有明显优势。其次,探讨了长江上游港口群的发展历史、发展态势及亟须协调的问题。主要港口由单一商贸功能向商贸加生产的综合功能转变,并通过多式联运积极拓展腹地,但港口生产能力过剩,且核心港区功能还有待加强。最后,对长江经济带战略背景下长江上游内河航运和港口群的发展提出建议,指出要加快形成港口群合力,建设重庆长江上游航运中心,完善核心港区功能。

长江经济带战略下成渝城市群交通发展研究

当前新发展理念对城市群交通发展提出新的要求。成渝城市群是长江经济带重要的城市群,也是西部地区经济基础最好、经济实力最强的城市群。论述成渝城市群当前发展存在的三个特征,即高首位度、内陆型城市群和多要素共存的旅游资源富集区。识别存在的三个交通问题,即成都、重庆枢纽的国际性有待提升,交通服务的不平衡、不充分问题仍然突出,行政分割和同质竞争突出。最后,提出未来交通发展的五个对策:强化大枢纽建设,完善城际铁路网,提升次级节点的枢纽功能,促进基础设施和政策的共建共享,支撑成都、重庆都市区交通发展。

京津冀协同背景下天津客运交通枢纽优化策略

天津客运交通枢纽既不能分担北京客运交通枢纽组织压力,又不能满足天津双城格局发展需要。因此,增强天津客运交通枢纽功能成为京津冀协同发展和天津自身发展的共同期望。首先,从天津铁路、航空枢纽在国家、区域层面的功能以及天津内部各铁路枢纽发展不均衡性的角度分析天津客运交通枢纽发展现状。其次,从京津冀建设世界级城市群和优化天津城市空间布局的角度分析天津客运交通枢纽优化的要求。最后,明确提出要从国家和区域两个层面研究天津铁路枢纽功能优化的总体思路,提出了以天津为中心的国家和区域层面铁路枢纽完善策略,并对天津滨海国际机场空铁联运提出建议。

从阶层、空间、交通互动视角解读交通规划

现行的交通规划理论基于均质化假设,并未充分考虑社会阶层以及不同阶层在职住关系、出行自由度方面的差异。城市交通发展中日益明显的设施错配、方式错配问题反映了特定阶层的交通需求与交通供给的不匹配。首先,梳理阶层、空间、交通三因素之间的关系,三者的不协调导致了设施错配和交通贫困,反映出交通规划和管理中存在“空间弱区”和“政策弱区”。其次,结合城市综合交通调查数据,对阶层、空间分异、出行自由度、错配、交通贫困、交通弱区、政策弱区等概念内涵及指标进行解析。最后,建议在交通规划理论和实践中充分考虑阶层因素并采取针对性的措施。

高铁网络化背景下普铁与城市的冲突与协调

随着高铁网络逐渐完善,在高铁、普铁共存的复合型通道上,普铁的功能逐渐发生分化,包括客货兼顾、以货为主、全部货运等。普铁与城市空间格局和城市功能随之出现了一系列的冲突,或是使原有冲突更加严重。首先分析高铁开通和逐渐成网对普铁的影响,提出普铁运输面临的三个问题:普铁与城市空间的冲突、普铁对货运系统的支撑和普铁专用线的优化利用。针对三个问题,通过案例形式总结普铁线路和城市功能的特征及匹配性,并分类别提出解决思路。