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Distinct vibrational signatures and complex phase behavior in metallic oxygen

Matter and Radiation at Extremes 2024年第2期9卷 4-11页

作者： philip dal.aday-simpson Bartomeu Monserrat Li Zhang Federico Gorelli Center for High Pressure Science Technology Advanced Research 1690 Cailun RoadShanghai 201203China Department of Materials Science and Metallurgy University of Cambridge27 Charles Babbage RoadCambridge CB3 OFSUnited Kingdom Cavendish Laboratory University of CambridgeJ.J.Thomson AvenueCambridge CB3 OHEUnited Kingdom Istituto Nazionale di Ottica Consiglio Nazionale delle Ricerche(CNR-INO)50125 FlorenceItaly Shanghai Advanced Research in Physical Sciences(SHARPS) ShanghaiChina

Evidence for metallization in dense oxygen has been reported for over 30 years[Desgreniers et al.,***.94,1117(1990)]at a now routinely accessible 95 GPa[Shimizu et al.,Nature 393,767(1998)].However,despite the longevity of this result and the technological advances since,the nature of the metallic phase remains poorly constrained[Akahama et al.,***.74,4690(1995);Goncharov et al.,***.B 68,224108(2003);Ma,***.B 76,064101(2007);and Weck et al.,***.102,255503(2009)].In this work,through Raman spectroscopy,we report the distinct vibrational characteristics of metallicζ-O_(2) from 85 to 225 *** comparison with numerical simulations,weﬁnd reasonable agreement with the candidate structure up to about 150 *** higher pressures,the C2/mstructure is found to be unstable and incompatible with experimental *** candidate structures,and Ci,with C2/m C2/conly two molecules in the primitive unit cell,are found to be stable and more compatible with measurements above 175 GPa,indicative of the dissociation of(O_(2))4 ***,we report and discuss a strong hysteresis and metastability with the precursory phaseϵ-O_(2).Theseﬁndings will reinvigorate experimental and theoretical work into the dense oxygen system,which will have importance for oxygen-bearing chemistry,prevalent in the deep Earth,as well as fundamental physics.

关键词： metallic phase vibrational

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Unveiling a novel metal-to-metal transition in LuH_(2):Critically challenging superconductivity claims in lutetium hydrides

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Matter and Radiation at Extremes 2024年第3期9卷 65-73页

作者： Dong Wang Ningning Wang Caoshun Zhang Chunsheng Xia Weicheng Guo Xia Yin Kejun Bu Takeshi Nakagawa Jianbo Zhang Federico Gorelli philip dal.aday-simpson Thomas Meier Xujie Lü Liling Sun Jinguang Cheng Qiaoshi Zeng Yang Ding Ho-kwang Mao Center for High-Pressure Science and Technology Advanced Research Beijing 100094China Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of SciencesBeijing 100190China Shanghai Key Laboratory of Material Frontiers Research in Extreme Environments(MFree) Shanghai Advanced Research in Physical Sciences(SHARPS)Shanghai 201203China

Following the recent report by Dasenbrock-Gammon et al.[Nature 615,244–250(2023)]of near-ambient superconductivity in nitrogendoped lutetium trihydride(LuH_(3-δ)N_(ε)),significant debate has emerged surrounding the composition and interpretation of the observed sharp resistance ***,we meticulously revisit these claims through comprehensive characterization and *** definitively identify the reported material as lutetium dihydride(LuH_(2)),resolving the ambiguity surrounding its *** similar conditions(270–295 K and 1–2 GPa),we replicate the reported sharp decrease in electrical resistance with a 30%success rate,aligning with the observations by Dasenbrock-Gammon et ***,our extensive investigations reveal this phenomenon to be a novel pressure-induced metal-to-metal transition intrinsic to LuH_(2),distinct from ***,nitrogen doping exerts minimal impact on this *** work not only elucidates the fundamental properties of LuH_(2)andLuH_(3),but also critically challenges the notion of superconductivity in these lutetium hydride *** findings pave the way for future research on lutetium hydride systems,while emphasizing the crucial importance of rigorous verification in claims of ambient-temperature superconductivity.

关键词： resistance hydride superconductivity

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Inhibition of rat prostate smooth muscle contractility by extracts of Costus speciosus(crepe ginger)

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Traditional Medicine Research 2022年第4期7卷 27-36页

作者： Nguok Ngie Su Jamie S.simpson philip EThompson Sabatino Ventura Drug Discovery Biology Monash Institute of Pharmaceutical SciencesMonash UniversityVIC 3052Australia Medicinal Chemistry Monash Institute of Pharmaceutical SciencesMonash UniversityVIC 3052Australia Sarawak Biodiversity Centre KM20Jalan Borneo HeightsSemengohKuching 93250Malaysia

Background:This study examined the chemistry and biological effects of Costus speciosus(***)Sm.(***)which has been traditionally used by Sarawak natives to treat urological disorders for ***:This study assesses the efficacy of *** in treating urological disorders by investigating its effects on the contractility of isolated prostate glands since this is the most effective way to relieve lower urinary tract symptoms that accompany benign prostatic *** were collected and extracts of *** rhizome,root,leaf and stem were made using water at different ***:*** rhizome and root decoction(boiling,about 100℃)combination extract(2 mg/mL)inhibited electrical field stimulation-induced neurogenic contractions of isolated rat prostatic gland by 44±8%(p=0.01,n=4);whereas room temperature(about 20℃)rhizome and root combination extract inhibited electrical field stimulation contractions by 62±8%(p=0.003,n=4).*** rhizome(p=0.0004,n=6),root(p<0.0001,n=6)and stem(p=0.0057,n=6)room temperature extracts inhibited electrical field stimulation-induced contractions of rat prostatic smooth muscle but leaf extract did not(p=0.09,n=6).Contractions mediated by exogenous administration of noradrenaline,acetylcholine,adenosine 5’-triphosphate or tyramine were only weakly inhibited by rhizome *** of *** rhizome room temperature extract separated by preparative high-performance liquid chromatography and evaluated by isolated organ bath bioassay revealed that inhibitory activity of the extract was due to highly polar soluble components present in the ***:*** extracts exert a direct inhibitory effect on prostate tissue which is likely to be therapeutically beneficial in treating lower urinary tract symptoms associated with benign prostatic hyperplasia.

关键词： benign prostatic hyperplasia Costaceae lower urinary tract symptoms smooth muscle contractility traditional medicines

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A REVIEW OF THE CHINA-GHANA BILATERAL INVESTMENT TREATY, 1989

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Frontiers of Law in China-Selected Publications from Chinese Universities 2017年第3期12卷 372-383页

作者： philip Ebow Bondzi-simpson Felix Awuah University of Toronto Toronto Canada London Metropolitan University London UK

Sino-Ghana business relationship has grown tremendously over the past two decades. The legal environment of this relationship will be analyzed critically and suggestions for improvement will be made in this article to further enhance this burgeoning relationship. In October 1989, Ghana and China signed an agreement concerning the encouragement and reciprocal protection of investment, known as the China-Ghana Bilateral Investment Treaty, which came into effect on November 22, 1991. There will be a review of this agreement which sought to provide an equitable treatment and enjoyment of protection in investments between the two countries based on the Most Favored Nation principle.

关键词： investment treaties China Ghana trade environment dispute resolution

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Everything you always wanted to know about metallic hydrogen but were afraid to ask

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Matter and Radiation at Extremes 2020年第3期5卷 25-30页

作者： Eugene Gregoryanz Cheng Ji philip dal.aday-simpson Bing Li Ross T.Howie Ho-Kwang Mao Centre for Science at Extreme Conditions and School of Physics and Astronomy University of EdinburghEdinburgh EH93FDUnited Kingdom Center for High Pressure Science and Technology Advanced Research Shanghai 201203China Key Laboratory of Materials Physics Institute of Solid State PhysicsChinese Academy of SciencesHefei 230031China

The hydrogen molecule is made from the first and lightest element in the periodic *** hydrogen gas is either compressed or cooled,it forms the simplest molecular *** solid exhibits many interesting and fundamental physical *** is believed that if the density of the solid is increased by compressing it to very high pressures,hydrogen will transform into the lightest known metal with very unusual and fascinating properties,such as room temperature superconductivity and/or *** this article,we provide a critical look at the numerous claims of hydrogen metallization and the current experimental state of affairs.

关键词： hydrogen metallic solid

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Structural Studies on the Cu–H System under Compression

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Engineering 2019年第3期5卷 505-509页

作者： Jack Binns Miriam Pena-Alvarez Mary-Ellen Donnelly Eugene Gregoryanz Ross T. Howie philip dal.aday-simpson Center for High Pressure Science and Technology Advanced Research (HPSTAR) Shanghai 201203 China Centre for Science at Extreme Conditions The University of Edinburgh Edinburgh EH9 3FD UK Key Laboratory of Materials Physics Institute of Solid State Physics Chinese Academy of Sciences Hefei 230031 China

Hydrogen chemistry at extreme pressures is currently subject to extensive research due to the observed and predicted enhanced physical properties when hydrogen is incorporated in numerous binary systems. Despite the high reactivity of hydrogen, the noble metals (Cu, Ag, and Au) display an outstanding resilience to hydride formation, with no reports of a stable compound with a hydrogen molar ratio - 1 at room temperature. Here, through extreme compression and in situ laser heating of pure copper in a hydrogen atmosphere, we explore the affinity of these elements to adopt binary compounds. We report on the phase behavior and stabilities in the Cu–H system, analyzed via synchrotron X-ray diffraction, up to pressures of 50 GPa. We confirm the existence of the previously reported c0-CuH0.15, c1-CuH0.5, and e-Cu2H phases. Most notably, we report the highest hydrogen-content noble-metal hydride stable at room temperature to date: c2-CuH0.65, which was synthesized through laser heating. This study furthers our understanding of hydrogen-transition metal chemistry and may find applicability in future hydrogen-storage applications.

关键词： High pressure Hydrogen storage Noble metal chemistry

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耗电极小的复位脉冲发生器

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电子设计技术 2003年第1期10卷 65-66页

作者： philip simpson Maxim Integrated Products Reading UK

当一个由处理器控制的装置必须可靠工作时,设计师往往不会选择依靠一种看门狗电路结构,而愿意选择使处理器定期复位的方式。在小功率系统中,这种定期复位电路会消耗系统电流预算的大部分,也可能在低电压下无法工作。图1所示的电路能产... 详细信息

当一个由处理器控制的装置必须可靠工作时,设计师往往不会选择依靠一种看门狗电路结构,而愿意选择使处理器定期复位的方式。在小功率系统中,这种定期复位电路会消耗系统电流预算的大部分,也可能在低电压下无法工作。图1所示的电路能产生一个宽度为100μS的下降沿复位脉冲。该电路消耗不到1μA的工作电流,并可由1.8～5V电源供电,而输出脉冲周期变化很小。该电路是由常规张驰振荡器改进而成的,它在输出端由一个微分器和二极管箝位,以便产生

关键词：复位脉冲下降沿工作电流输出脉冲电源电压

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