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| 1 | Measurement of Attenuation Q Value of Cylindrical Sample from Wave Energy显示文摘Two methods for measuring the attenuation Q value,frequency-amplitude ratio method andwaveform inversion method,were analyzed.The size and shape of most rock samples in thelaboratory can hardly fulfill the rigorous requirements of the above methods.A new testmethod of using the wave energy to calculate the Q value was proposed.The principle,calculation formulae and some points for attention were expounded;the relationship betweenQ_P and Q_E was discussed;and many samples were measured by this method.The result wascompared with those by other methods,and it was considered that the Q value by this methodlies between Q_P and Q_E· | Shi Xingjue, Ye Lin, Zhao Cuiping, Li Guangquan and Li WeidongDepartment of Earth and Space Sciences, University of Science and Technology of China,Advanced Center for Earth Science and Astronomy, Third World Academy of Science, Hefei 230026, China | 2000 | Earthquake Research in China2000，14，2： | 3 |
| 2 | Digital subtraction angiographic characteristics of progression of moyamoya disease 6 months prior to surgical revascularisation显示文摘background Evidence on the natural angiographic course of moyamoya disease(MMD)is lacking.It takes about 6 months for waiting for revascularisation surgery.The issue of when to perform subtraction angiography(DSA)for follow-up remains unclear.We investigated the natural course of MMD by DSA and attempted to determine the best interval to perform the follow-up DSA.Methods This is a single-centre cohort study of Chinese MMD inpatients treated from 1 January 2015 to 31 August 2019.Their angiographic findings were evaluated on Suzuki stage and collateral circulation between two follow-ups of the same hemisphere.results A total of 110 patients who met the criteria were enrolled in this study.After a median 6 months follow-up,five patients(4.5%)had progression,four females and one male.Time interval of progression ranged from 4 to 137 months with a mean of 61.4 months.Of five patients with progression,four had unilateral lesion(two ipsilateral and two contralateral)and one had bilateral lesions.Collateral circulation was changed in three of five patients.Conclusions The angiographic evidence of progression in MMD was rare in the short-term follow-up,and most patients with progression had initial unilateral involvement.DSA re-examination may be not needed in patients with bilateral MMD,but needed in unilateral MMD. | Peicong Ge Qian Zhang Xun Ye Xingju Liu Xiaofeng Deng Jia Wang Rong Wang Yan Zhang Dong Zhang Ji Zong Zhao | 2020 | Stroke & Vascular Neurology2020，5，1： | 1 |
| 3 | Negative differential friction coefficients of two-dimensional commensurate contacts dominated by electronic phase transition显示文摘Friction force(f)usually increases with the normal load(N)macroscopically,according to the classic law of Da Vinci–Amontons(f=μN),with a positive and finite friction coefficient(μ).Herein near-zero and negative differential friction(ZNDF)coefficients are discovered in two-dimensional(2D)van der Waals(vdW)magnetic CrI_(3)commensurate contacts.It is identified that the ferromagnetic–antiferromagnetic phase transition of the interlayer couplings of the bilayer CrI_(3)can significantly reduce the interfacial sliding energy barriers and thus contribute to ZNDF.Moreover,phase transition between the in-plane(p_(x)and p_(y))and out-of-plane(p_(z))wave-functions dominates the sliding barrier evolutions,which is attributed to the delicate interplays among the interlayer vdW,electrostatic interactions,and the intralayer deformation of the CrI_(3)layers under external load.The present findings may motivate a new concept of slide-spintronics and are expected to play an instrumental role in design of novel magnetic solid lubricants applied in various spintronic nano-devices. | Kun Liu Jiangtao Cheng Xingju Zhao Yandi Zhu Xiaoyan Ren Jinlei Shi Zhengxiao Guo Chongxin Shan Hongjie Liu Shunfang Li | 2022 | Nano Research2022，15，6： | 0 |
| 4 | An Overview of the Advanced Nonintrusive Measurement Techniques in Hypersonic Flow Field显示文摘Hypersonic flow-field measurement techniques have been studied for about 50 years. Despite truly remarkable progress with a probe or other device to measure the temperature, pressure or velocity, there are still serious problems for these 'intrusive' techniques. The intrusive measurement techniques introduce unexpected shock waves or flow-field structures, even make the boundary layer transition earlier and show a converse result. In recent years, nonintrusive diagnostics have been in urgent demand to give a more accurate and comprehensive flow-field for hypersonic testing. In this paper, an overview of some advanced nonintrusive measurement techniques such as embedded thermocouples for heat flux measurement, Pressure Sensitive Paint(PSP), Particle Image Velocimetry(PIV), infrared thermographs, and focusing Schlieren system are introduced. All of these techniques are nonintrusive and provide measurement of various parameters such as temperature, static pressure, dynamic pressure, flow velocity and visualization of flow structure, which gives us an exact and direct understanding of the hypersonic flow. | ZHAO Xuejun XIANG Xingju MA Yuanhong WANG Hongwei | 2017 | Aerospace China2017，18，4： | 0 |
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