State of the art and practice of pavement anti-icing and de-icing techniques

Pavement snow and icing are worldwide problems, but effective countermeasures are just beginning to be developed in China. The two most common snow and ice removal methods are mechanical clearance and chemical melting, and the advantages and disadvantages of each approach are discussed here, including environmental and structural damage caused by corrosive snow melting agents. New developments in chemical melting agents and mechanical equipment are discussed, and an overview of alternative thermal melting systems is presented, including the use of geothermy and non-geothermal heating systems utilizing solar energy, electricity, conductive pavement materials, and infrared/microwave applications. Strategic recommendations are made for continued enhancement of public safety in snow and ice conditions.

Super-hydrophobic film deposition by an atmospheric-pressure plasma process and its anti-icing characteristics

In this work,the super-hydrophobic(SH)surface was prepared through chemical vapor deposition process by an argon atmospheric pressure plasma jet source with HMDSN(hexamethyldisilazane)as the polymerization precursor.Plasma synthesized organosilicon(SiOxCyHz)thin films with water contact angle over 160°and sliding angle below 5°,were able to be achieved.FTIR and XPS analysis indicates a large number of hydrocarbon compositions were polymerized in the thin films enduing the latter very-low surface free energy.SEM shows the SH films display micro-nanostructure and with high degree of averaged surface roughness 190 nm evaluated by AFM analysis.From experiments under controlled low-temperature and moisture conditions,the prepared SH surface exhibits good anti-icing effects.Significantly prolonging freezing time was achievable on the SH thin films for both static and sliding water droplets.This investigation demonstrates the anti-icing potentials of SH surface prepared through low-cost simple atmospheric-pressure plasma polymerization process.

Design and Development of Anti-Icing Aluminum Surface

An anti-icing surface has been designed and prepared with an aluminum panel by creating an artificial lotus leaf which is highly hydrophobic. The hydrophobicity of a solid surface can be generated by decreasing its surface tension and increasing the roughness of the surface. On a highly hydrophobic surface, water has a high contact angle and it can easily rolls off, carrying surface dirt and debris with it. Super-cooled water or freezing rain can also run off this highly hydrophobic surface instead of forming ice on the surface, due to the reduction of the liquid-solid adhesion. This property can also help a surface to get rid of the ice after the water becomes frozen. In this study, a Cassie-Baxter rough surface was modeled, and an aluminum panel was physically and chemically modified based on the modeled structure. Good agreement was found between predicted values and experimental results for the contact and roll-off angles of water. Most importantly, by creating this highly hydrophobic aluminum rough surface, the anti-icing and de-icing properties of the modified surface were drastically improved compared to the control aluminum surface, and the cost will be reduced.

STUDY ON CONTACTING MELTING AND ANTI-SKID TECHNOLOGY FOR A TIRE TRACTION ON ICE

Theoretical analyses and experimental studies of the mechanisms of melting film formation are performed. The results show that frictional heating is the dominant mechanism because temperature behaves in the manner predicted by the theory of frictional heating. A study of the active technology for anti-skid is also made. Conclusions indicate that adjusting tire pneumatic pressure can improve the control stability and the travelling safety of an ice-automobile.

Investigation of Heterogeneous Ice Nucleation on the Micro-Cubic Structure Superhydrophobic Surface for Enhancing Icing-Delay Performance

The aim of this study is to explore the heterogeneous ice nucleation behavior based on controllable micro-cubic array structure surfaces from the statistic perspective.To this end,we firstly constructed a group of micro-cubic array structures on silicon substrates by a selective plasma etching technique.After grafting low-free-energy substance,the as-constructed micro-cubic array structure surfaces exhibited higher non-wettability with the water contact angle being up to 150°.On this basis,500 cycles of freezing and melting processes were accurately recorded to analyze the instantaneous ice nucleation behavior according to the statistical results of freezing temperature.As a consequence,the statistical freezing temperature of the sample with micro-spacing distance of 40μm is as low as−17.13°C.This microstructure configuration(conforming to Cassie-Baxter wetting regime)not only could entrap more air pockets,but also achieved lower solid-liquid contact area,resulting in lower ice nucleation rate(~2–3 orders of magnitude less than that on the flat substrate).Furthermore,the gradually increasing micro-spacing distance to 60μm would induce the transition from CassieBaxter to Wenzel wetting state,leading to higher freezing probability and ice nucleation rate.The complete understanding on microstructure configuration improving the ice nucleation will lay the foundation stone for the microstructure design of ice-repellent materials.

Anti-Icing Method Based on Reducing Voltage of Transmission Lines

The icing of transmission lines threatens the security of power system. This paper proposes a novel anti-icing method based on reducing voltage of the transmission lines. The line voltage can be reduced by regulating the ratio of the transformers which install the both ends of the transmission lines. The line current can be increased and the power loss of the transmission lines can also be increased, which means the heat generated by power loss increases and the icing process of the transmission lines can be restrained. When the icing may occur in the atrocious weather, the anti-icing transformers installed the both ends of transmission line are put into operation. The ratios of transformers are regulated to the appropriate value. The current of transmission line can be increased to the value that is a little greater than the critical current, which can realize the purpose of anti-icing. At the same time, the conditions of normal running in the load side are kept invariably, which can ensure the security of power system. This method can be applicable to a wide range. It's an effective measure to prevent the icing of the transmission lines.

Fast Algorithm for Prediction of Airfoil Anti-icing Heat Load

Many flight and icing conditions should be considered in order to design an efficient ice protection system to prevent ice accretion on the aircraft surface. The anti-icing heat load is the basic knowledge for the design of a thermal anti-icing system. In order to help the design of the thermal anti-icing system and save the design time, a fast and efficiency method for prediction the anti-icing heat load is investigated. The computation fluid dynamics (CFD) solver and the Messinger model are applied to obtain the snapshots. Examples for the calculation of the anti-icing heat load using the proper orthogonal decomposition (POD) method are presented and compared with the CFD simulation results. It is shown that the heat loads predicted by POD method are in agreement with the CFD computation results. Moreover, it is obviously to see that the POD method is time-saving and can meet the requirement of real-time prediction.

Corneal biomechanical data and biometric parameters measured with Scheimpflug-based devices on normal corneas

AIM： To analyze the correlations between ocular biomechanical and biometric data of the eye,measured by Scheimpflug-based devices on healthy subjects.METHODS： Three consecutive measurements were carried out using the corneal visualization Scheimpflug technology（Cor Vis ST） device on healthy eyes and the 10 device-specific parameters were recorded.Pentacam HR-derived parameters（corneal curvature radii on the anterior and posterior surfaces;apical pachymetry;corneal volume;corneal aberration data;depth,volume and angle of the anterior chamber） and axial length（AL） from IOLMaster were correlated with the 10 specific CorV is ST parameters.RESULTS： Measurements were conducted in 43 eyes of 43 volunteers（age 61.24±15.72y）.The 10 specific Cor Vis ST data showed significant relationships with corneal curvature radii both on the anterior and posterior surface,pachymetric data,root mean square（RMS） data of lower-order aberrations,and posterior RMS of higher-order aberrations and spherical aberration of the posterior cornea.Anterior chamber depth showed a significant relationship,but there were no significant correlations between corneal volume,anterior chamber volume,mean chamber angle or AL and the 10 specific CorV is ST parameters.CONCLUSION： Cor Vis ST-generated parameters are influenced by corneal curvature radii,some corneal RMS data,but corneal volume,anterior chamber volume,chamber angle and AL have no correlation with the biomechan-ical parameters.The parameters measured by CorV is ST seem to refer mostly to corneal properties of the eye.

Numerical Study on Ridge Ice Accretion and Its Effect Under Thermal Ice Protection

Under the condition of thermal anti-icing,the liquid water on the leading edge of the airfoil that would flow to the downstream non-protective zone will produce ridge ice,thus endangering flight safety.Based on the existing three-dimensional(3 D)icing model which considers the water film flow on the ice layer,an icing model with thermal boundary condition is introduced.With the boundary conditions of none anti-icing and thermal anti-icing,glaze ice accretion and ridge ice accretion are simulated on a simplified airfoil of unmanned aerial vehicle(UAV),and then the lift coefficient and drag coefficient are calculated and compared with the smooth airfoil under the same conditions.The results show that the lift-drag ratio obviously decreases after glaze ice occurred on the leading edge under the condition of none anti-icing;and that after setting the condition of anti-icing heat flux in the impingement area,the glaze ice on the leading edge becomes thinner and the ridge ice occurs in the non-protective zone,so the airfoil with this icing characteristic gets a lower lift-drag ratio.

Analysis of Severe Ice Accidents and Applied Countermeasures in China

Based on several typical severe ice accidents that occurred in China, this paper summarizes and analyzes the characteristics and causes for severe ice accidents. The results show that the ice accidents occurring in China have such characteristics as long duration, high frequency of occurrences, large coverage area and enormous loss to the national economy, etc. Drastic deterioration of mechanical property and electric property resulting from severe icing is the major cause of ice accidents. Besides, this paper summarizes the preventive measures for transmission lines in case of severe ice accidents.

风力发电机叶片防除冰涂层(二):温升数值计算及防除冰性能

针对电热超疏水涂层覆冰过程中表现出的三类不同冰层形貌,该文建立了电加热融冰数值计算模型,并对仿真计算结果进行了相应的试验验证,验证结果与仿真结果基本一致,该模型能有效模拟融冰过程和温度分布。临界融冰功率的计算结果表明,电热超疏水涂层融冰所需功率大于非超疏水电热涂层,尤其在乳突状冰层出现后,融冰功率将大幅增加。电热超疏水涂层防冰试验结果表明,在雨凇覆冰环境中,超疏水性能单独作用时,叶片在覆冰前期能延缓覆冰;电热性能与超疏水性能共同作用时,叶片无覆冰形成。电热超疏水涂层用于风力发电机防覆冰具有较好的效果,但用于覆冰后的融冰时将需要更多的能量。

以ChatGPT为代表的数字技术赋能冰雪体育旅游产业高质量发展:逻辑架构、要素协同及数字治理

习近平总书记关于“冰天雪地也是金山银山”的重要论述,为冰雪体育旅游产业高质量发展提供了行动指南。运用文献资料法等研究方法,基于新型冰雪体育旅游业态、消费模式不断涌现,形成多要素联动的基本结构集成化中枢耦合系统;战略目标多向度,三重效益协同;运行逻辑智能化、供需精准匹配的逻辑架构。以ChatGPT为代表的数字时代冰雪体育旅游产业高质量发展亟需数字治理要素协同,其中数字人才要素是创新根基、技术创新要素是原生性内生动力、产品创新要素是产业核心、数据资源要素是战略资源、渠道创新要素是联动保障,五大要素协同联动为冰雪体育旅游产业高质量发展提供数字治理指引:政策法规精准供给,强化软硬约束共促;打造立体监管机制,推进治理过程靶向施策;驱动治理主体双向触达,促进多元主体共治;精准配置治理资源,驱动要素禀赋转型升级。

含镍铬合金丝纬编电热层复合材料的拉伸性能

为开发一种航空飞行器防冰用电热复合材料,选取3种细度的镍铬合金丝,基于平针、罗纹和双罗纹3种纬编结构,优选了6种镍铬合金丝纬编电加热织物,以镍铬合金丝纬编织物为电热层,制备玻璃/环氧电热复合材料,并采用实验方法研究了镍铬合金丝细度和纬编结构对电加热织物及其复合材料的电热性能和对复合材料拉伸性能的影响。结果表明:同种纬编结构,镍铬合金丝细度较大,织物电热转换效率较低,电加热织物及其复合材料表面最高平衡温度较高,电热复合材料拉伸强度较小;同种镍铬合金丝细度,在11 V直流电压30 s下,平针组织电加热织物为电热层的复合材料表面温度由室温升高到74.1℃,升温速率达1.63℃/s,较罗纹和双罗纹组织升温速率分别高154.69%和33.61%;平针组织电加热织物为电热层的复合材料的拉伸强度为450.2 MPa,较罗纹和双罗纹组织拉伸强度分别高3.68%和4.53%。初步工作表明,含镍铬合金丝纬编电热层复合材料有望满足航空飞行器防冰用电热复合材料的需求。

基于记忆合金双程形状记忆效应的导线雾凇防冰方法及现场试验

输电线路覆冰严重威胁电力系统的安全运行,国内外学者对抑制导线覆冰的方法开展了大量研究。该文基于形状记忆合金在不同温度下保持不同形状的双程形状记忆效应,提出在导线表面布置形状记忆合金,利用其形状变化改变导线表面电场强度抑制导线覆冰的方法,实现输电线路不停电非人工干预式防冰。建立布置形状记忆合金导线的三维模型,并仿真分析其表面电场情况。结果表明,随着形状记忆合金形变量增大,导线表面电场强度逐渐增大。用两端向上弯曲的圆柱形铝条代替形状发生变化后的形状记忆合金,将其布置在LGJ-150/25导线表面,在重庆大学雪峰山能源装备安全国家野外科学观测研究站开展野外自然覆冰实验。实验结果表明,在导线表面布置代替形变后的记忆合金的铝条能够抑制导线的雾凇覆冰,且在导线初始表面电场强度为10 kV/cm时,效果最佳,覆冰质量和厚度分别降低了57.1%和48.7%。

基于POD和Kriging的水滴收集量快速预测方法

数值模拟手段预测翼面处水滴撞击特性通常较为耗时,为快速准确计算结冰条件下的翼面处水滴收集量,提出了基于本征正交分解和代理模型的水滴收集量快速预测方法。首先对FAR 25部附录C中连续最大结冰条件进行优化拉丁超立方采样,通过数值模拟手段获得各采样点在翼面处水滴收集量分布,从而构造样本空间。在此基础上,利用本征正交分解(Proper orthogonal decompostion,POD)方法找到表达和重构水滴收集量的本征模态以及相应的拟合系数。最后,利用Kriging模型建立样本空间中各采样点与拟合系数间的代理模型,实现翼面处水滴收集量分布的快速预测。经多组工况验证表明:该方法可较为准确地预测翼面处水滴收集量分布,其计算成本较数值模拟方法大幅降低,能够为无人机防除冰设计提供有益参考。

美国官方智库关于中美集成电路科技竞争的研究质量分析

[研究目的]集成电路产业是中美科技竞争的焦点,探究美国官方智库关于中美集成电路竞争的主要咨询建议,判断智库对美国政府决策和中美产业竞争走向的影响,为我国加强智库研究、促进集成电路产业发展提供借鉴。[研究方法]从多个相关领域的美国官方智库中筛选出4个代表性样本,采用内容分析和文献资料研究,解析样本智库在2015—2022年间的有关咨询建议。[研究结论]美国官方智库完全从支持政府实现遏制中国的战略目标出发提供建议,通过“旋转门”、广泛的成果宣传等机制影响政府决策,政府行动与智库的建议具有高度的一致性,但是智库研究的客观性、全面性不足。我国应选择性地借鉴美国经验,持续提高智库研究质量,为政府应对集成电路科技竞争提供有效的决策支持。

虚拟现实技术在冰雪娱乐运动中的应用研究

冰雪娱乐运动作为冬季旅游中代表性体验项目而倍受关注。通过运用数字技术手段宣传冰雪娱乐运动以满足更多爱好者的娱乐需求,降低旅客时间与金钱成本,值得设计开发研究。文章介绍国内冰雪娱乐运动项目与先进的虚拟现实技术的发展历程,阐述虚拟现实技术在冰雪娱乐运动的具体应用。

数字技术赋能冰雪产业链高质量发展研究

在后冬奥会时期,我国应秉承“冰天雪地就是金山银山”的理念,加速推进“冷冰雪、热经济”。数字技术已逐步应用于冰雪产业链的各层面之中,数字技术如何助力冰雪产业链高质量发展成为关注的焦点。全球的冰雪产业正面临着数字技术的挑战,在分析当前冰雪产业链发展面临的数字技术困境后,理清数字技术赋能冰雪产业链发展的内在逻辑,探讨数字技术赋能冰雪产业链高质量发展的路径。据此,应以数字技术推进冰雪产业链资源整合、打造数字化产品、催生冰雪产业新业态、助推冰雪产业链条完善、赋能冰雪产业营销宣传、促进冰雪旅游与文化产业协同发展,为我国的冰雪产业注入新的活力与动能。

产业链核心技术堵点识别与分析研究——以芯片产业为例

大国竞争格局下,全球产业链技术合作受限,进行技术堵点识别与分析对防范重大科技风险,突破技术封锁,实现产业链自主可控具有重要作用。本研究从专利视角出发,结合美国出口管制清单,采用文本分析法、对比分析法、LDA主题建模,将产业链技术竞争情报进行对比,构建了集成不同数据源开展关联分析的研究框架,对亟待突破却受到技术限制的核心技术堵点进行产业链定位,深度剖析核心专利竞争与出口管制政策的内在关系。在芯片领域实证研究发现在数字计算设备、印片设备与光刻工艺领域中国存在核心技术堵点,对应的产业链环节为制造设备与材料,存在核心专利被提前卡位问题,研发材料与创新技术路线可作为突破技术封锁实现自主可控的途径。本研究为复杂国际竞争下产业核心技术堵点发现与分析提供了一种新框架。