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Molecular behaviors in thin film lubrication——Part three: Superlubricity attained by polar and nonpolar molecules

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Friction 2019年第6期7卷 625-636页

作者： Xiangyu GE Tobias HALMANS Jinjin LI Jianbin LUO State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China RWTH Aachen University Aachen 52062Germany

In thin-film lubrication(TFL), generally, the viscosity of the lubricant and its coefficient of friction(Co F) increase. Finding a method to reduce the Co F in TFL is a significant challenge for tribologists. In the present work, we report a robust superlubricity attained by using polyalkylene glycols(pags, polar molecules) and poly-α-olefins(PAOs, nonpolar molecules) as lubricants on steel/steel friction pairs that have been pre-treated by wearing-in with polyethylene glycol aqueous solution(PEG(aq)). A steady superlubricity state with a Co F of 0.0045 for pag100 and 0.006 for PAO6 could be maintained for at least 1 h. Various affecting factors, including the sliding velocity, normal load, and viscosity of the lubricants, were investigated. Element analysis proved that composite tribochemical layers were deposited on the worn region after the treatment with PEG(aq). These layers were formed by the tribochemical reactions between PEG and steel and composed of various substances including oxides, iron oxides, Fe OOH, and Fe(OH)3, which contributed to the superlubricity. In addition to the tribochemical layers, ordered layers and a fluid layer were formed by the pags and PAOs during the superlubricity periods. All the three types of layers contributed to the superlubricity, indicating that it was attained in the TFL regime. Accordingly, a mechanism was proposed for the superlubricity of the pags and PAOs in the TFL regime in this work. This study will increase the scientific understanding of the superlubricity in the TFL regime and reveal, in the future, the potential for designing superlubricity systems on steel surfaces for industrial applications.

关键词： thin film lubrication superlubricity PEG pag PAO

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pag淬火液下40Mn钢带的淬火温度研究

热加工工艺 2023年第6期52卷 142-145,151页

作者：康泰宇郭纯营梦李云安徽科技学院机械工程学院安徽凤阳233100

设计不同试验方案,使用10%pag淬火液和空气作为淬火介质对40Mn钢带进行淬火试验,将完成淬火的钢带与未淬火的钢带进行拉伸试验和硬度测试,并使用金相显微镜观察了钢带的金相组织。通过数据对比发现,以空气为淬火介质的40Mm钢带在淬火温... 详细信息

设计不同试验方案,使用10%pag淬火液和空气作为淬火介质对40Mn钢带进行淬火试验,将完成淬火的钢带与未淬火的钢带进行拉伸试验和硬度测试,并使用金相显微镜观察了钢带的金相组织。通过数据对比发现,以空气为淬火介质的40Mm钢带在淬火温度为840℃时获得的钢带性能最佳,其抗拉强度为752.5 MPa,硬度为289.3HV0.2,金相显微组织为细小的珠光体和铁素体。使用pag淬火液作为淬火介质时,40Mn钢带在淬火温度为840℃时获得的试样性能最好,其抗拉强度为1682.9 MPa,硬度为623.8 HV0.2,金相显微组织主要为马氏体和少量残余奥氏体。将经空气和pag淬火液淬火后获得的试样参数与原材料试样的参数比较后可得:经空气淬火后,试样性能略有提升;经10%pag淬火液淬火后,试样性能显著提升。

关键词： pag 40Mn钢带淬火温度性能硬度

THE ROLE OF BRAIN-STEM DISCENDING INHIBITORY SYSTEM IN THE ANTINOCICEPTIVE EFFECT ELICITED BY MUSCLE SPINDLE AFFERENTS

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Academic Journal of Xi'an Jiaotong University 2001年第2期13卷 152-155页

作者：吴苏娣樊小力汪丛莹唐斌 Department of Physiology Med. Sch. of Xi'an Jiaotong Univ. Xi' an 710061 China

Objective To analyse the antinociceptive effect of muscle spindle afferents and the involved mechanism.Methods The single unit of wide dynamic range neurons in the spinal cord dorsal horn were recorded extracelluarly.The effects of muscle spindle afferents elicited by intravenous administration of succinylcholine on nociceptive responses (C fibres evoked responses,C responses) of WDR neurons were observed before and after bilateral lesions of ventrolateral periaqueduct gray .And the effects of muscle spindle afferents on the spontaneous discharge of the tail flick related cell in the rostral ventro medial medulla and on the spontaneous discharge of the pag neurons were observed.Results The C responses of WDR neurons were significantly inhibited by muscle spindle afferents,and the inhibitory effects were reduced by bilateral lesions of ventrolateral pag.The spontaneous discharge of the off cell in the RVM was excited while the on cell was inhibited by intravenous administration of Sch.The spontaneous discharge of the pag neurons were excited by muscle spindle afferents.Conclusion Muscle spindle afferents show a distinct effect of antinociception.pag RVM descending inhibitory system may play an important role in this nociceptive modulative mechanism.

关键词： muscle spindle antinociception WDR neurons succinylcholine pag RVM

Seasonal variations in serum pregnancy associated glycoproteins during early pregnancy in Aardi goats in central Saudi Arabia

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Asian pacific Journal of Reproduction 2017年第5期6卷 226-230页

作者： Mohamed J Al-Hassan Kamal A Al-Samawi Department of Animal Production College of Food and Agriculture SciencesKing Saud UniversityRiyadhSaudi Arabia Department of Animal Production Faculty of Agricultural Sciences and Veterinary MedicineThamar UniversityP.O.Box 87246ThamarYemen Republic

Objective:To accurately detect pregnancy in local Aardi goats of Saudi Arabia before day 30 of pregnancy by using serum caprine pregnancy associated glycoproteins (capag) concentrations and to evaluate the effects of heat stress on early pregnancy and on capag concentrations in pregnant and non-pregnant goats.Methods:This study was to confirm the reliability of our methods in different seasons of the year. A new protocol to evaluate and improve Aardi goats' reproductive performance was implemented during summer and winter months. A total of 60 healthy mature Aardi goats were used (30 and 30 in the summer and winter, respectively). All were synchronized using an ovsynch protocol and then naturally mated (NM) to mature tested bucks. Conception rates and capag were measured and pregnancy was verified by ultrasonography.Results:Regardless of season, however, on day 23 and 35 post-NM, capags were higher in sera of pregnant (Ppag concentrations on day 15. On day 23 and 35 post-NM, serum capag concentrations were higher (Ppag concentrations proved to be easy and accurate in assessing early stages of pregnancy (as early as 23 days post-NM) during both summer and winter seasons.Conclusions: It can be concluded that pregnancy rates were not affected by seasonal differences. The modified ovsynch program can be advantageous and worthwhile for its ease of use. When we add the accuracy of capag tests, such a program will help in detecting pregnancies in Aardi goats as early as 23 days post-NM, regardless of the season.

关键词： Ovsynch pag Early pregnancy diagnosis Summer Winter Aardi goats

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铝合金热处理用pag淬火剂

材料工程 1997年第1期25卷 14-16页

作者：赵海鸥 G.E.陶登 G.M.韦伯斯特 F.汤姆北京机电研究所美国联合碳化公司

综述已往的工作,确定pag水溶性淬火液中主要的一类(美国航天工业命名的typeⅠ)淬火剂在铝合金热处理应用可能性的范围。

关键词：聚合物淬火剂铝合金淬火 pag

ANTAGONISM OF MORPHINE ANALGESIA AND ELECTROACUPUNCTURE ANALGESIA BY CHOLECYSTOKININ OCTAPEPTIDE (CCK-8) ADMINISTERED TO PERIAQUE-DUCTAL GRAY (pag) OF THE RABBITS

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针刺研究 1989年第Z1期 148-149页

作者： Cao Wei Zhou Zhongfu Han Jisheng Department of physiology, Beijing Medical University

We have reported that intracerebroventricular (i. c. v.) injection of 1-4 ngof CCK-8 to the rat produced a remarkable antagonistic effect on morphineanalgesia. In order to study the species specificity and the site of action.CCK-8 was microadministered to the pag of the rabbit, and its influence onmorphine analgesia and electroacupuncture analgesia was observed.

关键词： CCK-8 OF THE RABBITS ANTAGONISM OF MORPHINE ANALGESIA AND ELECTROACUPUNCTURE ANALGESIA BY CHOLECYSTOKININ OCTAPEPTIDE ADMINISTERED TO PERIAQUE-DUCTAL GRAY pag

THE ROLE OF NEGATIVE FEEDBACK MODULATING PAIN OF NUCLEUS RAPHE MAGNUS IN ELECTRO-ACUPUNCTURE ANALGESIA

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针刺研究 1989年第Z1期 28-30页

作者： Liu Xiang Institute of Acupuncture and Moxibustion, China Academy of Traditional Chinese Medicine, Beijing, People’s Republic of China

In recent years I am interested in the role of nucleus raphe magnes (NRM)in acupuncture analgesia, NRM is the one of origins of important descendinginhibitory systems inclueded in the intrinsic anatgesic systems in brain, and wegave more systematic study on the question. The primary results are asfollows: 1. Experiments were perfored on male rats, unit discharges of NRMwere recorded extracellularly with glass electrode. The neurons responed tonoxious stimulation were chosen to observe analgesia of EA. The spontaneousfiring rates of NRM neurons were about 0.5-20Hz, a few of them over 20Hzor have no any discharges. NRM neurons have not often responses to non-noxious stimulation(to brush hair) or only have a light responses and adapt-ation appeared fast. But responses of them to noxious stimulation (to clampor to prick skin) or electrostimulation (20V) were obviously displayed with

关键词： THE ROLE OF NEGATIVE FEEDBACK MODULATING PAIN OF NUCLEUS RAPHE MAGNUS IN ELECTRO-ACUPUNCTURE ANALGESIA EA NRM pag

针刺对三叉神经尾侧脊束核(TNC)活动的影响及与pag或PGC微量注入脑啡肽(ENK)后影响的比较

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针刺研究 1990年第4期15卷 274-279页

作者：黄坤厚夏琅炎 J.P.Rosenfeld 中国中医研究院针灸研究所北京中医学院针推系 Dept of Psychology Northwestern University Evanston IL. U. S. A.

观察到针刺“合谷”后32个TNC伤害性反应神经元中26例发放增加,P<0.01;31例伤害性反应抑制,P<0.01。在14个TNC神经元上比较了针刺“合谷”与ENK微量注入pag后的影响:针刺后12例发放增加,P<0.05,而伤害性反应均抑制,P<0.01。ENK注入pag后... 详细信息

观察到针刺“合谷”后32个TNC伤害性反应神经元中26例发放增加,Ppag后的影响:针刺后12例发放增加,Ppag后,12例发放不变;伤害性反应均抑制,Ppag、PGC等;此外针刺信息也可激活TNC神经元发挥其抗痛作用。

关键词： TNC 神经元神经组织 pag ENK 针刺 PGC

EFFECT OF ELECTRICAL STIMULATING MIDBRAIN PERIAQUEDUCTAL GRAY(pag) ON RESPONSES OF SPINAL CORD AND CEREBRAL CORTEX TO SLOW PAIN

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针刺研究 1989年第Z1期 9-10页

作者： Wang Baoqing Chen Peixi Department of Physiology, Sun Yat-Sen University of Medical Sciences, Guangzhou

In this artical the effect of stimulating pag on C-CEP was observed in order to provide some data for the research of slow pain modulation. Experiments were performed on cats under choloralose anaesthesis andimmobitized by gallamine triethiodide. After blocking A-fibers input by anodalcurrent the superficial peroneal nerve was stimulated with strong electricalpulse, and the C-fiber input was elicited selectively. The evoked potentialswere recorded on the back surface of ipsilateral spinal cord (C-SSP) andcontralateral cerebral somatosensory area (C-CEP). pag was stimulated withshort electrial pulse.

关键词： pag CEP EFFECT OF ELECTRICAL STIMULATING MIDBRAIN PERIAQUEDUCTAL GRAY ON RESPONSES OF SPINAL CORD AND CEREBRAL CORTEX TO SLOW PAIN