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Boundary-refl ected waves and ultrasonic coda waves in rock physics experiments

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Applied Geophysics 2016年第4期13卷 667-682,739页

作者： fu Bo-Ye fu li-yun Wei Wei Zhang Yan Key Laboratory of Petroleum Resource Research Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China University of Chinese Academy of Sciences Beijing 100049 China

Ultrasonic coda waves are widely usea to stuay hign-trequency scattering, however, ultrasonic coda waves are strongly affected by interference from by boundary-reflected waves. To understand the effect of boundary-reflected waves, we performed ultrasonic experiments using aluminum and shale samples, and the rotating staggered-mesh finite-difference method to simulate the wavefield. We analyzed the wavefield characteristics at the different receiving points and the interference characteristics of the boundary-reflected waves with the ultrasonic coda wave, and the effect of sample geometry on the ultrasonic coda waves. The increase in the aspect ratio of the samples delays the interference effect of the laterally reflected waves and reduces the effect on the ultrasonic coda waves. The main waves interfering with the ultrasonic coda waves are laterally reflected PP-, PS-, PPP-, and PPS-waves. The scattering and attenuation of the high-frequency energy in actual rocks can weaken the interference of laterally reflected waves with the ultrasonic coda waves.

关键词： Rock physics boundary-reflected waves coda wave interference numerical simulation

老年重症肺炎miR-146a和miR-127与miR-21表达水平及其预测价值

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中华医院感染学杂志 2024年第11期34卷 1626-1630页

作者：钟婉红郝金香黄一桂陈兰符丽云海口市第三人民医院呼吸与危重症医学科海南海口571100

目的探讨老年重症肺炎患者微小核糖核酸(miR)-146a、miR-127、miR-21表达水平及其预测价值.方法选取海口市第三人民医院2020年11月-2022年11月收治的110例老年重症肺炎患者(重症肺炎组)、同期120例普通肺炎患者(普通肺炎组)及同期120名... 详细信息

目的探讨老年重症肺炎患者微小核糖核酸(miR)-146a、miR-127、miR-21表达水平及其预测价值.方法选取海口市第三人民医院2020年11月-2022年11月收治的110例老年重症肺炎患者(重症肺炎组)、同期120例普通肺炎患者(普通肺炎组)及同期120名健康体检者(健康组),比较所有研究对象血清miR-146a、miR-127、miR-21水平,分析重症肺炎组患者病原菌情况;根据预后分为存活组(79例)和死亡组(31例),分析老年重症肺炎患者死亡的危险因素,分析血清miR-146a、miR-127、miR-21对老年重症肺炎患者死亡的诊断价值.结果与健康组相比,普通肺炎组和重症肺炎组血清miR146a、miR-127、miR-21水平较高,且重症肺炎组高于普通肺炎组(P<0.05);老年重症肺炎患者共培养分离病原菌110株,其中革兰阴性菌86株占78.18%,革兰阳性菌20株占18.18%,真菌4株占3.64%;机械通气、miR-146a、miR-127、miR-21是老年重症肺炎患者死亡的危险因素(OR=2.421、1.237、2.467、2.519,P<0.05);miR-146a、miR-127、miR-21单独检测老年重症肺炎患者死亡的曲线下面积(AUC)值低于联合检测(P<0.05).结论老年重症肺炎患者血清miR-146a、miR-127、miR-21水平较高,感染革兰阴性菌的比例较高;机械通气、血清miR-146a、miR-127、miR-21是老年重症肺炎患者死亡的危险因素,且血清miR-146a、miR-127、miR-21水平联合检测老年重症肺炎患者死亡的价值较高.

关键词：重症肺炎老年微小RNA-146a 微小RNA-127 微小RNA-21 受试者工作特征曲线

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A li_(3)P nanoparticle dispersion strengthened ultrathin li metal electrode for high energy density rechargeable batteries

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Nano Research 2024年第5期17卷 4031-4038页

作者： lin fu Xiancheng Wang Bao Zhang Zihe Chen Yuanjian li Yongming Sun Provincial Guizhou Key Laboratory of Green Chemical and Clean Energy Technology School of Chemistry and Chemical EngineeringGuizhou UniversityGuiyang 550025China Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China School of Physical and Mathematical Sciences Nanyang Technological UniversitySingapore 637371Singapore Institute of Materials Research and Engineering Agency for Science Technology and Research(A*STAR)Singapore 138634Singapore

Achievement of lithium(li)metal anode with thin thickness(e.g.,≤30µm)is highly desirable for rechargeable high energy density ***,the fabrication and application of such thin li metal foil electrode remain challenging due to the poor mechanical processibility and inferior electrochemical performance of metallic ***,mechanico-chemical synthesis of robust ultrathin li/li_(3)P(LLP)composite foils(~15µm)is demonstrated by employing repeated mechanical rolling/stacking operations using red P and metallic li as raw *** in-situ formed li+-conductive li_(3)P nanoparticles in metallic li matrix and their tight bonding strengthen the mechanical durability and enable the successful fabrication of free-standing ultrathin li metal composite ***,it also reduces the electrochemical li nucleation barrier and homogenizes li plating/stripping *** matching to high-voltage liCoO_(2),the full cell with a low negative/positive(N/P)capacity ratio of~1.5 offers a high energy density of~522 W·h·kg^(-1) at 0.5 C based on the mass of cathode and *** into account its facile manufacturing,potentially low cost,and good electrochemical performance,we believe that such an ultrathin composite li metal foil design with nanoparticle-dispersion-strengthened mechanism may boost the development of high energy density li metal batteries.

关键词： lithium metal anode high energy density battery mechanico-chemical synthesis ultrathin li/li_(3)P composite foil low negative/positive capacity ratio

Catalytic anode surface enabling in situ polymerization of gel polymer electrolyte for stable li metal batteries

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Nano Research 2024年第6期17卷 5216-5223页

作者： Guocheng li Kang liang Yuanjian li Xiangrui Duan lin fu Zhao Cai Zhaofu Zhang Jiangnan Dai Yongming Sun Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China The Institute of Technological Sciences Wuhan UniversityWuhan 430074China Faculty of Materials Science and Chemistry China University of Geoscience(Wuhan)Wuhan 430074China

Employing quasi-solid-state gel polymer electrolyte(GPE)instead of the liquid counterpart has been regarded as a promising strategy for improving the electrochemical performance of li metal ***,the poor and uneven interfacial contact between li metal anode and GPE could cause large interfacial resistance and electrochemical li stripping/plating inhomogeneity,deteriorating the electrochemical ***,we proposed that the functional component of composite anode could work as the catalyst to promote the in situ polymerization reaction,and we experimentally realized the integration of polymerized-dioxolane electrolyte and li/li_(22)Sn_(5)/liF composite electrode with low interfacial resistance and good stability by in situ catalyzation ***,the reaction kinetics and stability of metallic li anode were significantly *** a demonstration,symmetric cell using such a GPE-li/li_(22)Sn_(5)/liF integration achieved stable cycling beyond 250 cycles with small potential hysteresis of 25 mV at 1 mA·cm^(−2)and 1 mAh·cm^(−2),far outperforming the counterpart regular GPE on pure *** with liNi0.5Co0.3Mn0.2O2,the full cell with the GPE-li/li_(22)Sn_(5)/liF integration maintained 85.7%of the original capacity after 100 cycles at 0.5 C(1 C=200 mA·g^(−1)).Our research provides a promising strategy for reducing the resistance between GPE and li metal anode,and realizes li metal batteries with enhance electrochemical performance.

关键词： catalyzation polymerization interface resistance interfacial stability li metal batteries electrochemical performance

Born序列频散方程和Born-Kirchhoff传播算子

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地球物理学报 2010年第2期53卷 370-384页

作者：符力耘中国科学院地质与地球物理研究所地球深部重点实验室北京100029

传统的Kirchhoff传播算子结构简洁,适用于描述横向均匀介质中波的传播.Ray-Kirchhoff传播算子较为精确地描述了波在非均匀介质中传播的运动学特征,其理论上的先天不足依赖于介质的复杂性.本文通过Born序列逼近波在非均匀介质中传播的大... 详细信息

传统的Kirchhoff传播算子结构简洁,适用于描述横向均匀介质中波的传播.Ray-Kirchhoff传播算子较为精确地描述了波在非均匀介质中传播的运动学特征,其理论上的先天不足依赖于介质的复杂性.本文通过Born序列逼近波在非均匀介质中传播的大角度波分量,提出一种Born-Kirchhoff传播算子,将传统Kirchhoff传播算子的适用范围扩展至非均匀介质,同时描述波的运动学和动力学特征,其精度取决于Born序列逼近的阶数.利用Born序列频散方程,可以精确分析各阶Born-Kirchhoff传播算子对波长、传播角和非均质性的尺度依赖特征,其中,一阶Born-Kirchhoff传播算子的精度高于传统的相屏传播算子.波数域的Born-Kirchhoff传播算子对于高波数波是奇异的,导致波数域数值计算发散,但其空间域版本是非奇异的,无条件数值稳定,可通过Kirchhoff求和数值实施.本文给出各阶Born-Kirchhoff传播算子及其频散方程,可用于不同程度非均匀介质中的波传播模拟,复杂构造地震成像和速度估计.本文利用零阶和一阶Born-Kirchhoff传播算子计算简单二维模型的合成地震图,并与边界元法进行了比较.

关键词：波传播 Born序列逼近 Born序列频散方程 Born—Kirchhoff传播算子非均匀介质

Application of a concrete thermal pile in cooling the warming permafrost under climate change

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Advances in Climate Change Research 2024年第1期15卷 170-183页

作者： yun-Hu SHANG fu-Jun NIU Guo-Yu li Jian-Hong FANG Ze-Yong GAO State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China Da Xing'anling Observation and Research Station of Frozen-Ground Engineering and Environment Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesJagdaqi 165000China Qinghai Research Institute of Transportation Xining 810008China

Permafrost degradation caused by climate warming is posing a serious threat to the stability of cast-in-place pile foundations in warm permafrost *** cold energy can be effectively utilized by two-phase closed thermosyphons(TPCTs)to cool the ***,we installed TPCTs in a cast-in-place pile foundation to create a unique structure called a thermal pile,which effectively utilizes the TPCTs to regulate ground *** we conducted a case study and numerical simulation to exhibit the cooling performance,and optimize the structure of the thermal *** purpose of this study is to promote the application of thermal piles in unstable permafrost *** on the findings,the thermal pile operated for approximately 53%of the entire year and effectively reduced the deep ground temperature at a rate of at least-0.1℃per ***,it successfully raised the permafrost table that is 0.35 m shallower than the natural ground *** characteristics prove highly beneficial in mitigating the adverse effects of permafrost degradation and enhancing infrastructure *** the length of the condenser section and the diameter of the TPCT in a suitable manner can effectively enhance the cooling capability of the thermal pile and ensure the long-term mechanical stability of the pile foundation even under climate warming.

关键词： Heat transfer Cold energy Warm permafrost Two-phase closed thermosyphons Cast-in-place pile foundation

Towards an ultrafast 3D imaging scanning liDAR system: a review

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Photonics Research 2024年第8期12卷 1709-1729页

作者： ZHI li YAQI HAN liCAN WU ZIHAN ZANG MAOliN DAI SZE yun SET SHINJI YAMASHITA QIAN li H.Y.fu Tsinghua Shenzhen International Graduate School Tsinghua University Department of Electrical Engineering and Information Systems The University of Tokyo Research Center for Advanced Science and Technology The University of Tokyo School of Electronic and Computer Engineering Peking University

light detection and ranging (liDAR), as a hot imaging technology in both industry and academia, has undergone rapid innovation and evolution. The current mainstream direction is towards system miniaturization and integration. There are many metrics that can be used to evaluate the performance of a liDAR system, such as lateral resolution, ranging accuracy, stability, size, and price. Until recently, with the continuous enrichment of liDAR application scenarios, the pursuit of imaging speed has attracted tremendous research interest. Particularly, for autonomous vehicles running on motorways or industrial automation applications, the imaging speed of liDAR systems is a critical bottleneck. In this review, we will focus on discussing the upper speed limit of the liDAR system. Based on the working mechanism, the limitation of optical parts on the maximum imaging speed is analyzed. The beam scanner has the greatest impact on imaging speed. We provide the working principle of current popular beam scanners used in liDAR systems and summarize the main constraints on the scanning speed. Especially, we highlight the spectral scanning liDAR as a new paradigm of ultrafast ***, to further improve the imaging speed, we then review the parallel detection methods, which include multiple-detector schemes and multiplexing technologies. furthermore, we summarize the liDAR systems with the fastest point acquisition rate reported nowadays. In the outlook, we address the current technical challenges for ultrafast liDAR systems from different aspects and give a brief analysis of the feasibility of different approaches.

关键词： Frequency combs High speed imaging Optical access networks Remote sensing Single pixel imaging Spatial light modulators

Safety and efficacy of transcatheter arterial embolization in autosomal dominant polycystic kidney patients with gross hematuria: Six case reports

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World Journal of Clinical Cases 2024年第11期12卷 1954-1959页

作者： Wei-Fan Sui yun-Xin Duan Jian-yun li Wei-Bin Shao Jian-Hua fu Department of Interventional Radiology Zhenjiang First People's HospitalZhenjiang 212000Jiangsu ProvinceChina Department of Nephrology Zhenjiang First People’s HospitalZhenjiang 212000Jiangsu ProvinceChina

BACKGROUND To retrospectively report the safety and efficacy of renal transcatheter arterial embolization for treating autosomal dominant polycystic kidney disease(ADPKD)patients with gross *** SUMMARY The purpose of this study is to retrospectively report the safety and efficacy of renal transcatheter arterial embolization for treating ADPKD patients with gross *** and methods:During the period from January 2018 to December 2019,renal transcatheter arterial embolization was carried out on 6 patients with polycystic kidneys and gross *** arteriography was performed first,and then we determined the location of the hemorrhage and performed embolization under digital subtraction angiography *** in routine blood test results,routine urine test results,urine color and postoperative reactions were observed and ***:Renal transcatheter arterial embolization was successfully conducted in 6 *** indices of 5 patients and the color of gross hematuria improved after surgery compared with before *** severe complication reactions *** For autosomal dominant polycystic kidney syndrome patients with gross hematuria,transcatheter arterial embolization was safe and effective.

关键词： Renal artery Autosomal dominant polycystic kidney disease Gross hematuria Interventional radiology Embolization Case report

Novel sandwich structured glass fiber Cloth/Poly(ethylene oxide)-MXene composite electrolyte

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Nano Materials Science 2024年第1期6卷 60-67页

作者： Yu-Qin Mao Guang-He Dong Wei-Bin Zhu Yuan-Qing li Pei Huang Shao-yun fu College of Aerospace Engineering Chongqing UniversityChongqing400044China State Key Laboratory of Power Transmission Equipment and System Security and New Technology Chongqing UniversityChongqing400044China

Recently,poly(ethylene oxide)(PEO)-based solid polymer electrolytes have been attracting great attention,and efforts are currently underway to develop PEO-based composite electrolytes for next generation high performance all-solid-state lithium metal *** this article,a novel sandwich structured solid-state PEO composite electrolyte is developed for high performance all-solid-state lithium metal *** PEO-based composite electrolyte is fabricated by hot-pressing PEO,liTFSI and Ti_(3)C_(2)T_(x) MXene nanosheets into glass fiber cloth(GFC).The as-prepared GFC@PEO-MXene electrolyte shows high mechanical properties,good electrochemical stability,and high lithium-ion migration number,which indicates an obvious synergistic effect from the microscale GFC and the nanoscale *** as,the GFC@PEO-1 wt%MXene electrolyte shows a high tensile strength of 43.43 MPa and an impressive Young's modulus of 496 MPa,which are increased by 1205%and 6048%over those of ***,the ionic conductivity of GFC@PEO-1 wt%MXene at 60℃ reaches 5.01×10^(-2) S m^(-1),which is increased by around 200%compared with that of GFC@PEO *** addition,the li/li symmetric battery based on GFC@PEO-1 wt%MXene electrolyte shows an excellent cycling stability over 800 h(0.3 mA cm^(-2),0.3 mAh cm^(-2)),which is obviously longer than that based on PEO and GFC@PEO electrolytes due to the better compatibility of GFC@PEO-1 wt%MXene electrolyte with li ***,the solid-state li/liFePO_(4) battery with GFC@PEO-1 wt%MXene as electrolyte demonstrates a high capacity of 110.2–166.1 mAh g^(-1) in a wide temperature range of 25–60C,and an excellent capacity retention *** developed sandwich structured GFC@PEO-1 wt%MXene electrolyte with the excellent overall performance is promising for next generation high performance all-solid-state lithium metal batteries.

关键词： Solid polymer electrolyte Ti_(3)C_(2)T_(x)MXene Poly(ethylene oxide) Glass fiber cloth All-solid-state li metal Battery