How Generative Adversarial Networks Promote the Development of Intelligent Transportation Systems:A Survey

In current years,the improvement of deep learning has brought about tremendous changes:As a type of unsupervised deep learning algorithm,generative adversarial networks(GANs)have been widely employed in various fields including transportation.This paper reviews the development of GANs and their applications in the transportation domain.Specifically,many adopted GAN variants for autonomous driving are classified and demonstrated according to data generation,video trajectory prediction,and security of detection.To introduce GANs to traffic research,this review summarizes the related techniques for spatio-temporal,sparse data completion,and time-series data evaluation.GAN-based traffic anomaly inspections such as infrastructure detection and status monitoring are also assessed.Moreover,to promote further development of GANs in intelligent transportation systems(ITSs),challenges and noteworthy research directions on this topic are provided.In general,this survey summarizes 130 GAN-related references and provides comprehensive knowledge for scholars who desire to adopt GANs in their scientific works,especially transportation-related tasks.

Direct Observation of Carrier Transportation Process in InGaAs/GaAs Multiple Quantum Wells Used for Solar Cells and Photodetectors

The resonant excitation is used to generate photo-excited carriers in quantum wells to observe the process of the carriers transportation by comparing the photoluminescence results between quantum wells with and without a p-n junction. It is observed directly in experiment that most of the photo-excited carriers in quantum wells with a p-n junction escape from quantum wells and form photoeurrent rather than relax to the ground state of the quantum wells. The photo absorption coei^cient of multiple quantum wells is also enhanced by a p-n junction. The results pave a novel way for solar cells and photodetectors making use of low-dimensional structure.

Active tuning of anisotropic phonon polaritons in natural van der Waals crystals with negative permittivity substrates and its application in energy transport

Phonon polaritons(PhPs)exhibit directional in-plane propagation and ultralow losses in van der Waals(vdW)crystals,offering new possibilities for controlling the flow of light at the nanoscale.However,these PhPs,including their directional propagation,are inherently determined by the anisotropic crystal structure of the host materials.Although in-plane anisotropic PhPs can be manipulated by twisting engineering,such as twisting individual vdW slabs,dynamically adjusting their propagation presents a significant challenge.The limited application of the twisted bilayer structure in bare films further restricts its usage.In this study,we present a technique in which anisotropic PhPs supported by bare biaxial vdW slabs can be actively tuned by modifying their local dielectric environment.Excitingly,we predict that the iso-frequency contour of PhPs can be reoriented to enable propagation along forbidden directions when the crystal is placed on a substrate with a moderate negative permittivity.Besides,we systematically investigate the impact of polaritonic coupling on near-field radiative heat transfer(NFRHT)between heterostructures integrated with different substrates that have negative permittivity.Our main findings reveal that through the analysis of dispersion contour and photon transmission coefficient,the excitation and reorientation of the fundamental mode facilitate increased photon tunneling,thereby enhancing heat transfer between heterostructures.Conversely,the annihilation of the fundamental mode hinders heat transfer.Furthermore,we find the enhancement or suppression of radiative energy transport depends on the relative magnitude of the slab thickness and the vacuum gap width.Finally,the effect of negative permittivity substrates on NFRHT along the[001]crystalline direction ofα-MoO3 is considered.The spectral band where the excited fundamental mode resulting from the negative permittivity substrates is shifted to the first Reststrahlen Band(RB 1)ofα-MoO_(3) and is widened,resulting in more significant enhancement of heat flux from RB 1.We anticipate our results will motivate new direction for dynamical tunability of the PhPs in photonic devices.

Unleashing the Potential of Unidirectional Mechanical Materials: Breakthroughs and Promising Applications

The emergence of mechanically one-way materials presents an exciting opportunity for materials science and engineering. These substances exhibit unique nonreciprocal mechanical responses, enabling them to selectively channel mechanical energy and facilitate directed sound propagation, controlled mass transport, and concentration of mechanical energy amidst random motion. This article explores the fundamentals of mechanically one-way materials, their potential applications across various industries, and the economic and environmental considerations related to their production and use.

The challenges facing the oil and gas storage and transportation technology and its developing direction

In recent years, our country is increasingly dependent on the use of the oil resources, and the degree of the oil mining is also continuously upgrading. After the completion of the tasks related to the oil mining in the lands, the technologies for the development of the offshore oil mining are particularly important. Among these problems, after the exploitation, the storage and transportation of the offshore oil and gas is worthy of the discussion of the technical personnel. From the experience of the oil and gas storage and transportation in the long years, in some environmentally degraded areas, there are problems in the efficiency and safety in the long pipeline transportation and the oil and gas mixed transportation, and in the transportation, there are also big shortcomings. In this paper, the author carries on the analysis of the existing questions encountering in our country＇s oil and gas storage and transportation~ and proposes the direction of the researches in the future oil and gas storage and transportation, and the purpose is to better improve the security of Cbina＇s oil and gas storage and transportation and to enhance the efficiency of the use of the oil and gas.

Directed Transport of Interacting Particle Systems： Recent Progress

Recent developments in studies of directed transport processes in interacting particle systems are retrospected. Due to the interactions among elements, the directed transport process exhibits complicated and novel cooperative dynamics. We considered various possibilities in achieving ratchet motion by breaking different symmetries of many-body systems. It is shown that the directional transport can even be induced by breaking the coupling symmetry and the spatiotemporal symmetries.

Collective Directional Transport in Symmetric Periodic Potentials by Breaking the Coupling Symmetry

Collective unidirectional motion of an asymmetrically coupled array of oscillators in symmetric periodic potentials is studied. A directed current is observed when the drift coupling is presented, while no external biased force is applied. Negative directed current is found when varying system parameters. An addition of a periodic rocking force may enhance the efficiency of directed transport. Resonant steps of the current are found and interpreted as the mode locking between the array and the ac force. Noise-assisted transport is observed, and an optimal noise intensity can give rise to a most efficient transport. The directed transport thus can be optimized and furthermore controlled by suitably adjusting the parameters of the system.

On the Quadratic Transportation Problem

We present a direct analytical algorithm for solving transportation problems with quadratic function cost coefficients. The algorithm uses the concept of absolute points developed by the authors in earlier works. The versatility of the proposed algorithm is evidenced by the fact that quadratic functions are often used as approximations for other functions, as in, for example, regression analysis. As compared with the earlier international methods for quadratic transportation problem (QTP) which are based on the Lagrangian relaxation approach, the proposed algorithm helps to understand the structure of the QTP better and can guide in managerial decisions. We present a numerical example to illustrate the application of the proposed method.

Directed transport of coupled Brownian motors in a two-dimensional traveling-wave potential

Considering an elastically coupled Brownian motors system in a two-dimensional traveling-wave potential, we investigate the effects of the angular frequency of the traveling wave, wavelength, coupling strength, free length of the spring, and the noise intensity on the current of the system. It is found that the traveling wave is the essential condition of the directed transport. The current is dominated by the traveling wave and varies nonmonotonically with both the angular frequency and the wavelength. At an optimal angular frequency or wavelength, the current can be optimized. The coupling strength and the free length of the spring can locally modulate the current, especially at small angular frequencies. Moreover, the current decreases rapidly with the increase of the noise intensity, indicating the interference effect of noise on the directed transport.

Controlling the Directed Quantum Transport of Ultracold Atoms in an Optical Lattice with a Periodic Driving Field

We propose a new method to control the directed quantum transport of ultracold atoms in a one-dimensional optical lattice. In this proposal, the effective tunneling between the neighboring sites can be adjusted via coherent destruction of tunneling by tuning the phase of the external field, instead of using the driving field intensity or the frequency, thus the directed quantum transport of ultracold atoms can be coherently controlled in a nmch easier manner. Our proposal overcomes the major drawback of the method used by Creffield et al [Phys. Rev. Lett. 99 （2007） 110501], and can be implemented, in principle, in any one-dimensional optical lattice. Some potential applications of the scheme are also discussed.

ITER氦冷固态实验包层模块第一壁氢同位素双向输运数值分析

氦冷固态实验包层模块(HCCB-TBM)安装于国际热核聚变实验堆(ITER)中,用以验证HCCB包层概念的氚增殖能力与热移出能力。HCCB-TBM第一壁用于承受堆芯等离子体粒子轰击和包容内部功能材料。外侧等离子体驱动氘、氚粒子渗透与内侧氢分压驱动渗透的同时存在,形成了第一壁的双向氢同位素输运。此双向输运可能对第一壁外表面再循环系数、包层增殖氚的纯化产生重要影响。基于商业软件COMSOL建立第一壁双向氢同位素输运模型,研究第一壁的氢同位素的输运特征。仿真结果表明:第一壁中的冷却剂流道具有强的氢同位素移出能力,使得双向输运解耦合;在ITER等离子体脉冲周期中,放电过程中已扩散到材料内部的氚在等离子体关停时扩散回流到真空室侧,关停时的回流将降低向冷却剂流道的氚渗透损失。

“双碳”目标下氢能产业技术发展分析

氢能作为清洁、高效的能源,对于实现全球能源转型和碳中和目标至关重要.随着全球能源需求增长和气候变暖挑战,世界各国都在积极推动能源绿色转型.氢能不仅可替代部分化石燃料,还是可再生能源的有效补充.近年来,全球能源领域正在经历绿色转型,氢能产业得到长足发展,其在交通、储能、工业等方面应用范围得到显著增长.从分析氢能产业技术入手,总结国内外氢能产业发展现状,梳理目前氢能产业面临的问题,展望氢能产业未来发展方向,全面阐述氢能链发展进展.未来,氢能预计将成为全球能源转型和实现气候目标的关键力量,促进清洁能源应用,为经济带来新增长点,对缓解气候变暖和提升能源安全具有重要意义.

国Ⅵ直喷汽油机颗粒数量及微观形貌排气输运演变特性

开展了某一国Ⅵ直喷汽油机三元催化转化器(TWC)前、TWC后、汽油机颗粒捕集器(GPF)后3个位置的颗粒物采样及微观形貌研究,分析了发动机工况、TWC、GPF对国Ⅵ直喷汽油机尾气颗粒数量、粒径分布、微观形貌的影响。结果表明,该直喷汽油机尾气颗粒数量排放整体上呈单峰分布,低转速小负荷工况下,粒径<23nm的颗粒数量较高。随着发动机转速和负荷的增大,峰值粒径向大粒径方向移动。直喷汽油机尾气颗粒物由“核‒壳”结构基本碳粒子堆积形成,呈链状、枝状、簇状等结构;负荷增大,颗粒物尺寸略有增大,基本碳粒子重叠度增强,分形维数增大;转速增大,颗粒物尺寸减小,基本碳粒子重叠度减弱,分形维数减小。随着排气输运的进行,颗粒数量逐渐降低;TWC不影响颗粒的粒径分布形态,颗粒数量净化效率41.6%~94.2%,对<23 nm的小粒径颗粒净化效果较好,低转速小负荷工况的颗粒数量净化效率较高;GPF的颗粒数量净化效率约80%,23~100 nm颗粒数量净化效率较高,对粒径<10nm的颗粒净化作用不大。TWC和GPF不影响颗粒物结构形式,TWC和GPF后颗粒物基本碳粒子重叠度减弱,分形维数减小。

可见光抗菌的单向导湿自泵织物

具有湿度管理和抑菌性能的功能织物可以有效提高穿着舒适度。现有方法往往通过在亲水织物表面物理浸涂抗菌剂,虽然可起到短效抑菌作用,但会导致抗菌剂大量突释,引起皮肤不适,抗菌能力快速减弱。本文利用静电纺丝方法制备了一种掺杂可见光激发抗菌光敏剂的自泵织物(Self-pumping textile,SPT),实现了汗液的单向移除同时高效抗菌。自泵织物由疏水的聚偏二氟乙烯-六氟丙烯(PVDF-HFP)纤维和亲水的碱水解醋酸纤维素(CA)纤维组成,其中亲水纤维中掺杂了具有高活性氧产生能力的聚噻吩(PT2)光敏剂。在接触角导液模型中,我们证实了导液时间随疏水层厚度增加而延长,当疏水层电纺时间为60 s时,水分可以在10 s内从疏水层单向导出到亲水层。使用功率为25 mW/cm^(2)的氙灯光模拟日常太阳光进行抗菌,结果表明,10 min可以杀灭95%以上的金黄色葡萄球菌和大肠杆菌。本工作为功能性织物的设计提供了一种新的思路。

考虑物流时效的电商农产品供应链演化博弈研究

针对直播电商背景下农产品供应链中存在的生鲜农产品到货不及时以及消费者购买意向低等问题,对电商平台、物流企业和消费者构建三方演化博弈模型,分析各方的博弈行为和演化稳定策略。根据市场上物流企业存在的时效性较差和较好两种情形,运用MATLAB软件进行数值仿真,探究在不同主播努力水平下影响该动态系统演化趋势及演化稳定策略的关键因素。研究发现:平台押金和物流期望满意值的变化在物流时效性较差时影响物流企业和消费者的策略选择;主播佣金比率和平台增值服务投入与电商平台选择高效运营的概率在物流时效性较好时呈负相关关系;减少消费者增值服务有利于平台长期发展和降本增效。研究结果结合直播电商运营情况对农产品供应链提出建议。

仿生集水纤维研究进展及应用

淡水资源短缺是全球共同面临的严峻挑战。相关研究发现,模仿蜘蛛丝等生物结构从空气中收集水分,是缓解当前水资源危机的有效途径,已成为仿生集水领域的研究焦点。本文从基础润湿理论、液滴定向传输机理、定向集水机制、仿生纤维设计特点及制备方法等方面进行了综述,重点介绍了Young’s方程、Wenzel模型以及Cassie-Baxter模型等基础润湿理论。将纤维集水过程划分为冷凝结露、定向运输和液滴脱附3个阶段,并深入阐述了蜘蛛丝集水过程的内在机制,包括拉普拉斯压力梯度、表面能梯度、滞后效应和液滴悬挂能力。分析了影响集水效率的关键因素,并列举了提升纤维集水效率的常用策略。归纳了仿生纤维结构的主要仿生对象、仿生原理以及所采用的主要制备技术,并对不同技术的优缺点及适用场景进行了详细分析。最后,对不同仿生纤维网状集水器的集水特点和集水效率进行了比较,分析了仿生纤维集水技术在大气水收集、海水淡化、工业蒸气回收以及油水分离等领域的应用潜力,并对该技术的未来发展方向及现有不足提出了改进意见和展望。

摇摆运动下低流率蒸汽冷凝换热特性和气泡受力数值模拟

蒸汽直接接触冷凝具有高效的传热传质性能,广泛应用于核能安全等领域。低质量流率蒸汽直接接触冷凝具有低频压力振荡,易引发设备共振。相比陆地稳定工况,海洋条件下摇摆运动可能加剧气液界面振荡,进一步影响设备的安全运行。为此,通过数值模拟对摇摆条件下低流率蒸汽凝结过程进行研究,分析了摇摆条件下压力、换热特性和气泡受力的变化规律,结果表明压力和传热系数剧烈波动主要集中于气泡颈缩和脱离阶段,此时气泡受力也达到最大值,气泡主要受惯性力和凝结力作用。此外,对比静止工况和摇摆工况,发现摇摆条件下由气泡速度变化导致的惯性力部分增大,摇摆运动带来的附加摇摆速度强化了气液界面的换热性能,平均传热系数远高于静止工况。

不同铁矿物对酱香型白酒封窖泥厌氧消化的影响

通过向废弃窖泥厌氧消化系统中分别添加强氧化性的水铁矿和弱氧化性但有导电性的磁铁矿,考察Fe(Ⅱ)、有机物、微生物群落结构等的变化,探究不同类型Fe(Ⅲ)矿物对窖泥厌氧消化的影响。结果表明,水铁矿组富集铁还原菌,Fe(Ⅱ)含量第12天迅速增加至900 mg/L,表明水铁矿发生了异化铁还原。磁铁矿组与对照组中Fe(Ⅱ)含量几乎一致,说明磁铁矿没有发生异化铁还原。水铁矿组和磁铁矿组中COD去除量分别比空白组增加了16.1%和4.9%,表明水铁矿和磁铁矿均促进了有机物的去除。磁铁矿组富集了Geobacter和Methanosarcina,促进了直接种间电子传递(DIET),增加了23.4%的甲烷产量,而水铁矿抑制甲烷化,降低了32.2%的甲烷产量。

基于重力驱动液滴定向运输的主动式抗细菌黏附及抗菌研究

有害细菌黏附在各种材料表面会时刻危害着人类生命健康,每年为应对有害细菌黏附所付出的经济成本数以亿计。黏附在材料表面的细菌最终将形成难以清除的生物膜,预防细菌在初始阶段的黏附可以显著减少生物膜的形成,这是应对细菌黏附的有效途径。迄今为止,预防细菌的初始黏附所采用的手段包括超疏水表面、超亲水表面、润滑表面和智能响应型防黏附表面等。但上述提到的绝大多数抗细菌黏附手段属于静态的被动式抗细菌黏附策略,本研究提出了一种基于重力驱动实现液滴定向运输的主动式抗细菌黏附策略,并且结合银纳米粒子负载的杀菌区构建了一种新型主动式抗细菌黏附系统。通过实验探究了微坡高度、倾角与液滴运动的关系,并得到了最优条件。动态抗细菌黏附测试发现对大肠杆菌和金黄色葡萄球菌的抗黏附率高达99.71%和98.79%,具有良好的主动抗细菌黏附效果,验证了重力驱动细菌液滴定向运输主动式抗细菌黏附策略的有效性。末端杀菌区不但具有良好的被动抗黏附效果,并且可以有效地杀死运动至杀菌区的细菌液滴,对大肠杆菌和金黄色葡萄球菌的抗菌率高达100%和100%。本研究提出的基于重力驱动实现液滴定向运输的主动式抗细菌黏附策略的抗黏附效果显著,构建的整个新型主动式抗细菌黏附系统具有良好的抗细菌黏附和杀菌能力,为应对细菌黏附提供了一种全新的策略,在生物医学、微流控技术和工业生产等领域具有重要的应用前景。

基于车船直取模式的集装箱海铁联运衔接优化

为解决车船直取模式下集装箱海铁联运衔接优化问题,基于固定的船期,本文考虑火车班列和集装箱船在时间和运量两个维度上的衔接,以衔接班列数量最大化、衔接船舶数量和时刻表调整最小化为目标,构建海铁联运班列时刻表优化的混合整数非线性规划模型,并基于分层优化方法进行求解。以深圳盐田港为例,对模型进行分析验证。结果表明:考虑时间和运量衔接的班列时刻表优化,可以带来衔接的班列数量增加6个,车船直取集装箱总量增加466 TEU,提高了75%;衔接的船舶数量增加了1个,3艘船装载的车船直取箱量分别提高了2.6%、4.2%和2.5%;集装箱在港口总停留时间缩短了26%。研究表明,该模型可为改善港口车船直取模式下海铁联运衔接水平提供有益参考。