Peridynamic modeling and simulation of thermo-mechanical de-icing process with modified ice failure criterion

De-icing technology has become an increasingly important subject in numerous applications in recent years.However,the direct numerical modeling and simulation the physical process of thermomechanical deicing is limited.This work is focusing on developing a numerical model and tool to direct simulate the de-icing process in the framework of the coupled thermo-mechanical peridynamics theory.Here,we adopted the fully coupled thermo-mechanical bond-based peridynamics(TM-BB-PD)method for modeling and simulation of de-icing.Within the framework of TM-BB-PD,the ice constitutive model is established by considering the influence of the temperature difference between two material points,and a modified failure criteria is proposed,which takes into account temperature effect to predict the damage of quasi-brittle ice material.Moreover,thermal boundary condition is used to simulate the thermal load in the de-icing process.By comparing with the experimental results and the previous reported finite element modeling,our numerical model shows good agreement with the previous predictions.Based on the numerical results,we find that the developed method can not only predict crack initiation and propagation in the ice,but also predict the temperature distribution and heat conduction during the de-icing process.Furthermore,the influence of the temperature for the ice crack growth pattern is discussed accordingly.In conclusion,the coupled thermal-mechanical peridynamics formulation with modified failure criterion is capable of providing a modeling tool for engineering applications of de-icing technology.

On the Construction of Deepening Anti - corruption Mechanism

It needs the foundation of system and the guarantee of organizational system for anti-corruption,but it is more necessary to build and form an effective anti-corruption mechanism,so that the anti-corruption can be really put into practice. Anti-corruption mechanism refers to a organic operation system of the interaction,interconnection and constraint between the constituent elements( parts) and elements of national anti-corruption,and as a system,anti-corruption mechanism should have the characteristics of system aticness,comprehensiveness,transparency,legalization,public participation,scientific dynam ic,and internationalism. The construction of deepening anti-corruption mechanism is the need for reconstructing the ruling legitimacy of the party and the governm ent. Adhering to the principle of treating both root causes and symptoms is necessary in the construction of anti-corruption m echanism,com bating and punishing corruption is an important part of anti-corruption,and the prevention and control of corruption is the basic project of anti-corruption. Therefore,the construction of prevention and control mechanism in the anti-corruption mechanism has a more far-reaching significance.

Advances in Research on Anti-cancer Mechanism of 18β Glycyrrhetinic Acid

Glycyrrhiza uralensis Fisch has been used to treat the symptoms of organ fever, food poisoning, typhoid fever, sore throat, cough due to lung heat, children's diseases and so on since the ancient times. It is a solid Chinese herbal medicine which is good for the health. In recent years, it has been found that licorice extract also has excellent anti-cancer effect. The 18β glycyrrhetinic acid, obtained by hydrolysis of precursor glycyrrhizic acid, is a relatively efficient anti-cancer ingredient. 18β glycyrrhetinic acid can exert anti-cancer effects by inhibiting cancer cell proliferation, inducing apoptosis of cancer cells, inhibiting invasion and metastasis of cancer cells, preventing oxidation, inhibiting neovascularization, inhibiting lymphangiogenesis, and regulating hormone secretion. This paper reviewed the advances in research of the anticancer mechanism of 18β glycyrrhetinic acid, to provide a theoretical basis for future research.

Study about anti-request design of transmission mechanism in job device of colliery sump cleaner

The paper takes reversal hexagon connecting bar mechanism which uses in colliery sump cleaner as research object, takes main performance of reversal hexagon connecting bar in loader as target and uses the idea of anti request project and modern design, raises a new method of engineering design. It has proved that the method is feasibility and correct by practice.

Anti-oxidation mechanism of SiC-B_4C-C composites

Mixture of green petroleum coke, B4C and SiC together with short carbon fiber were employed as starting materials, the mixture was press-formed without any binder after grinding, dense and homogeneous binderless SiC-B4C-C（carbon/ceramic） composites were then obtained after sintering. Composites thus prepared possess excellent anti-oxidation property, that is, mass loss less than 1% within the temperature range from 900 to 1100℃ for 10h. Anti-oxidation mechanism was also discussed from the viewpoint of thermodynamics, excellent anti-oxidation property of materials thus prepared can be discribed to 1) solid SiO2 formed from SiC, which restrains the filtering of oxygen and simultaneously, its volume expansion brought about by the reaction takes roles both walling up the （original） pores and making the material more compact; 2) liquid B2O3 from the reaction of B4C not only makes the combination with C, B4C and SiC tighter through forming solid solution, but also effect of reaction SiC（s）+2CO（g）=SiO2（s）+3C（s） is an expansive process, which improves the microstructure of the material.

Anti-Fertility Effects and Mechanism of the Plant Extract Shikonin on Mice

Controlling fertility of rodent pests has become an effective means of controlling the population of grassland rodents in China. Recently, research has focused on how to select environmentally-friendly sterilants without pollution effects, and to realize sustainable control of pest rodent populations. Sterilants from plant extracts have been mainly selected. In this study, mice were used as the experimental subjects for research on the anti-fertility effects of plant extracts of shikonin and the anti-fertility mechanism of shikonin extract was determined. The mice were divided into four groups, including one control group and three experimental groups. There were three applications of shikonin extract in different concentrations (5 mg·kg-1, 20 mg·kg-1 and 50 mg·kg-1). The mice gavage experiments indicated that a shikonin concentration of 50 mg·kg-1 had the expected anti-fertility effects. Mice copulation experiments showed that the 50 mg·kg-1 shikonin treatment had significant anti-fertility effects on both female-treatment and female-male-treatment groups. The results of the PCR analysis on the AgRP and ghrelin mRNA from female ovaries and male testicles indicated that shikonin could control mice reproduction by regulating the pituitary gonadal axis. Shikonin, as plant source sterile agent, would have more ideal effects for functioned both sexes sterility.

Design and Analysis of Electro-mechanical Hybrid Anti-lock Braking System for Hybrid Electric Vehicle Utilizing Motor Regenerative Braking

Braking on low adhesion-coefficient roads, hybrid electric vehicle＇s motor regenerative torque is switched off to safeguard the normal anti-lock braking system （ABS） fimction. When the ABS control is terminated, the motor regenerative braking is readmitted. Aiming at avoiding permanent cycles from hydraulic anti-lock braking to motor regenerative braking, a novel electro-mechanical hybrid anti-lock braking system using fuzzy logic is designed. Different from the traditional single control structure, this system has a two-layered hierarchical structure, The first layer is responsible for harmonious adjustment or interaction between regenerative system and anti-lock braking system. The second layer is responsible for braking torque distribution and adjustment. The closed-loop simulation model is built. Control strategy and method for coordination between regenerative and anti-lock braking are developed. Simulation braking on low adhesion-coefficient roads with fuzzy logic control and real vehicle braking field test are presented. The results from simulating analysis and experiment show braking performance of the vehicle is perfect, harmonious coordination between regenerative and anti-lock braking function, significant amount of braking energy can be recovered and the proposed control strategy and method are effective.

Numerical simulation of solid tumor angiogenesis with Endostatin treatment:a combined analysis of inhibiting effect of anti-angiogenic factor and micro mechanical environment of extracellular matrix

To investigate the influence of anti-angiogenesis drug Endostatin on solid tumor angiogenesis, a mathematical model of tumor angiogenesis was developed with combined influences of local extra-cellular matrix mechanical environment, and the inhibiting effects of Angiostatin and Endostatin. Simulation results show that Angiostatin and Endostatin can effectively inhibit the process of tumor angiogenesis, and decrease the number of blood vessels in the tumor. The present model could be used as a valid theoretical method in the investigation of anti-angiogenic therapy of tumors.

Numerical investigation of unsteady mixing mechanism in plate film cooling

A large-scale large eddy simulation in high performance personal computer clusters is carried out to present unsteady mixing mechanism of film cooling and the development of films. Simulation cases include a single-hole plate with the inclined angle of 30° and blowing ratio of 0.5, and a single-row plate with hole-spacing of 1.5D and 2D （diameters of the hole）. According to the massive simulation results, some new unsteady phenomena of gas films are found. The vortex system is changed in different position with the development of film cooling with the time marching the process of a single-row plate film cooling. Due to the mutual interference effects including mutual exclusion, a certain periodic sloshing and mutual fusion, and the structures of a variety of vortices change between parallel gas films. Macroscopic flow structures and heat transfer behaviors are obtained based on 20 million grids and Reynolds number of 28600.

Research Progress on Molecular Mechanism of Moxibustion in the Treatment of Ankylosing Spondylitis

As an important part of traditional Chinese medicine (TCM) nursing technology, moxibustion plays a unique role in improving the symptoms of ankylosing spondylitis (AS). The research on the mechanism of moxibustion intervention in AS mainly focuses on anti-inflammatory effects, immune regulation, bone metabolism regulation, intestinal flora regulation, and so on. Molecular medicine is of great significance to further clarify the mechanism of moxibustion intervention in AS. However, there are still some problems in the research on the molecular mechanism of moxibustion intervention in AS: the existing biomedical research methods only explore from a specific field and lack the exploration of moxibustion-targeted molecules based on biomedical network. In the future, the molecular network effect of moxibustion on AS can be discussed comprehensively and systematically with the help of omics technology and the construction of biological information interaction network between omics. The effect of moxibustion on upstream osteogenic transcription factors and related signaling pathways such as WNT, β-catenin, and BMP/Smads is not yet clear. Future research can focus on the relevant signal targets of bone reconstruction and clarify the mechanism of moxibustion against the new bone formation. In addition, there is a lack of research on the molecular mechanism of moxibustion in the treatment of AS from the perspective of metabolites. It is necessary to further explore the mechanism of moxibustion in the treatment of AS with the help of metabonomics technology.

麦冬抗肿瘤作用机制研究进展

麦冬是我国的传统中药,具有养阴生津、润肺清心的功效。越来越多的研究发现,麦冬除了传统功效外还具有对多种肿瘤的抑制作用。麦冬可通过抑制肿瘤细胞增殖、诱导肿瘤细胞凋亡、坏死性凋亡、铁死亡、焦亡、自噬、细胞周期阻滞、抑制肿瘤细胞转移和血管生成以及逆转肿瘤细胞耐药性等多种机制发挥抗肿瘤作用。对近年来麦冬块根提取物及其活性单体的抗肿瘤作用研究进展进行综述,为麦冬抗肿瘤的深入研究和对麦冬的进一步开发利用提供可借鉴的思路和方向。

甘草抗炎活性物质基础及其作用机制研究进展

炎症是机体对于刺激所产生的一种防御反应,随着炎症的发展可能导致组织的变异和增生,进一步加剧疾病的进程。甘草作为“众药之王”“国之药老”,早在《神农本草经》中就记载其清热作用较强,能“主五脏六腑寒热邪气”。现代研究表明,甘草提取物对肾小球肾炎、结肠炎症状改善明显,甘草及其制剂在治疗肝炎、胃炎、支气管炎、心肌炎、强直性脊柱炎等炎症性疾病方面亦具有一定的独特优势和发展潜力。该文旨在通过对近期国内外甘草抗炎活性物质基础及其作用机制方面的相关文献进行收集和整理,探索甘草发挥抗炎作用的主要活性成分及靶点通路,以期为甘草抗炎作用的进一步研究及抗炎药物的研发提供思路和参考。

道路沥青紫外老化及抗老化材料研究综述

道路沥青材料在使用过程中由于长期受到太阳光紫外辐射作用会产生紫外老化现象,并且这种现象在紫外辐射强度高的地区更明显。紫外老化会使沥青的物理特性和化学组成发生改变,从而导致沥青黏塑性上升、低温和疲劳性能下降、使用裂缝增加,进而劣化路面的耐久性、影响沥青路面的运营品质和服役寿命。为了防止和延缓紫外老化的产生和发展,可在道路沥青中添加抗老化材料以增强其抵御紫外老化能力,同时延长沥青路面的使用寿命并降低其性能的衰变速率。本文阐述了基于自由基和胶体理论的紫外老化机理;从处理方式、光源与辐射强度选择等方面介绍了室内模拟老化试验条件;总结了紫外老化对沥青物理和流变性能、组分构成、微观形貌、特征峰和官能团等宏微观特性的影响;归纳了现行抗老化材料的优缺点和使用情况。分析表明后期可在老化机理深度、试验方法标准化、室外老化监测、微观数值模拟、抗紫外老化剂针对性和抑制紫外老化措施等方面开展进一步研究。

利用SRV试验机研究温度对润滑剂摩擦学性能的影响

介绍了一种自行研究建立的测定润滑剂抗擦伤失效温度的试验方法,这是摩擦学领域性能评价的一个新发展。利用该试验方法评价了几种润滑剂摩擦因数随温度变化的情况并确定抗擦伤失效温度,对典型样品摩擦学性能随温度变化的情况进行了机理探讨,以期为相关润滑剂研发人员提供帮助和指导。

不同风化程度花岗岩的动态力学特性及抗侵彻性能

风化会使岩石材料孔隙发育,严重影响其工程性能,研究风化作用对花岗岩力学特性及抗侵彻性能的影响,对侵彻战斗部毁伤效能评估及地下工程防护能力分析具有重要意义。选用两种不同风化程度的花岗岩为研究对象,基于试验法系统分析其物理特性、静/动态压缩性能及抗侵彻性能的差异。结果表明:风化作用会造成花岗岩中黑云母和斜长石含量降低,孔隙率增加、内部组织变松散,缺陷加剧;风化作用将导致花岗岩抗压强度劣化、应变率效应降低,破坏模式从脆性破坏向弱剪切破坏转变;三轴围压作用下,两种花岗岩的静、动态抗压强度随围压的增大显著提升,且中风化花岗岩的抗压强度对围压的作用更敏感;高速(873~1040 m/s)侵彻条件下,两种风化花岗岩的抗侵彻性能差异较小,无量纲侵深不超过3倍弹长,岩石靶中不存在明显的侵彻弹道区,但有明显的压碎区,压碎区长度约为弹径的5~8倍。

小檗碱抗胃癌的药理作用及其机制研究进展

胃癌的发病率和死亡率在我国各种恶性肿瘤中均位居第三,是威胁人民生命健康的重要杀手。小檗碱除具有抗炎、抗感染、调节心血管等作用外,对肝癌、结直肠癌、脑瘤、头颈部肿瘤、泌尿系肿瘤等也有较好的作用,因而可能是一个潜在的抗肿瘤药物。该文主要从小檗碱预防胃癌的发生,以及对SGC7901、BGC-823、MKN-45等人胃癌细胞的抑制和诱导凋亡等方面进行了综述,以期为小檗碱的进一步临床开发提供参考。

植酸/茶多酚整理棉织物的阻燃及防紫外线性能

为解决棉织物易燃烧和抗紫外线性能差的问题,提高其使用安全性,采用浸轧和喷涂结合的方法,通过植酸(PA)和茶多酚(Tea)协同作用制备了阻燃/抗紫外线棉织物,并研究了其阻燃、防紫外线、拉伸以及透气性性能。结果表明:质量分数2.5%的PA和25 g/L的Tea复合整理的棉织物,其质量增加率仅为13.3%,而极限氧指数LOI值从原棉织物的17.5%提高到30.4%,离火自熄;PA/Tea整理棉织物与原棉织物相比,不仅热释放速率峰值(PHRR)下降了78.2%,其总热释放量(THR)和热释放能力(HRC)也分别下降了70.8%和78.3%,这意味着PA/Tea整理棉织物可以降低火灾放热强度,阻碍火焰快速传播;整理后的棉织物对UVB和UVC区域的紫外线具有良好的吸收性能,在实现阻燃和防紫外线功能的同时,保留了85.1%以上的透气性。

中药抗电离辐射药理作用及机制研究进展

中药具有高效、低毒、多靶点、特异性强等特点,其在辐射防护方面有着独特的优点。基于辐射对机体中免疫系统、造血系统和生殖系统的相关细胞及其通路损伤,以及DNA损伤和抗氧化应激,本文论述了近十年来中药及其复方抗辐射药理作用及机制的研究进展,并提出现有研究存在的问题,以期为后续新型辐射防护剂的中药产品开发提供参考。

炭黑/废纸导电纤维的制备及其在聚丙烯中的应用

利用多巴胺氧化自聚合将炭黑粘附到废纸纤维表面,制备了炭黑/废纸柔性导电纤维,分析了炭黑含量对纤维导电性能的影响,然后,将该导电纤维与聚丙烯熔融共混制备复合材料,分析了导电纤维添加量对复合材料导电和力学性能的影响。结果表明,聚多巴胺将炭黑均匀粘附在废纸纤维表面,纤维的电阻率随着炭黑含量增加而逐渐降低,当炭黑含量为15%时,废纸纤维的电阻率logρ下降至2.16Ω·cm。柔性导电纤维能更好地控制聚丙烯复合材料电导率降低幅度,当纤维添加量为15%(炭黑含量为2.27%)时,复合材料的表面电阻率为3.71×10^(10)Ω,体积电阻率为2.45×10^(11)Ω·cm,能达到抗静电级别。此时,复合材料的弹性模量和拉伸强度分别为565.65和17.01 MPa,模量提高了1.07%,但强度降低了32.82%。

融合注意力机制的ResNeXt语音欺骗检测模型

针对残差神经网络在语音欺骗检测中存在超参数过多且对于高频特征显著性突出不够的问题,提出一种融合注意力机制的ResNeXt-Attention网络(RA-Net)。RA-Net采用残差结合分组卷积的方式,用一组小卷积核代替大卷积核,且采用MFM(Max Feature Map)作为新的拼接方法。加入的注意力机制通过学习原始特征的信息,减少了对边缘信息的关注。在ASVspoof2019数据集上实验表明,RA-Net相比基准线高斯混合模型(GMM)的等错误率(EER)降低了4.72百分点和6.23百分点,与残差网络(Residal Neural Network,ResNet)相比EER降低了0.69百分点和0.89百分点,证明了该模型的有效性。