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41.
具备可进入的绿色空间、游乐场地是儿童友好城市衡量中的核心指标,也是城市公园提供的必要服务之一。聚焦对城市公园需求度和使用率较高的学龄前儿童,尝试建构综合考虑城市公园品质和可达性的分析及评估方法。选取联合国儿童友好城市——西班牙巴塞罗那为案例,基于实地调研、开源地图、官方统计数据等,使用儿童友好的公园品质指数(QUINPY)和空间句法可达性模型开展综合评价,并结合学龄前儿童人口密度分布,提出有针对性的改善建议,基于不同的需求和现状,选取改善城市交通步行环境、合理增加结构性设施或者鼓励分时段及立体化拓展空间使用可能性等适宜性创新措施。以期为我国儿童友好导向的城市公园发展建设提供参考。 相似文献
42.
Jun-Hao Liu Zhuang Ge Qian Wang Geng Wang Li-Na Sheng Wen-Wen Ge Xing Xu Peng Shuai Qi Zeng Bo Wu 《核技术(英文版)》2019,30(10)
A foil–microchannel plate(MCP) detector,which uses electrostatic lenses and possesses both good position and timing resolutions, has been designed and simulated for beam diagnostics and mass measurements at the next-generation heavy-ion-beam facility HIAF in China. Characterized by low energy loss and good performances of timing and position measurements, it would be located at focal planes in fragment separator HFRS for position monitoring, beam turning, Bρ measurement, and trajectory reconstruction. Moreover, it will benefit the building-up of a magnetic-rigidity–energy-loss–time-offlight(Bρ-△E-TOF) method at HFRS for high-precision in-flight particle identification of radioactive isotope beams on an event-by-event basis. Most importantly, the detector can be utilized for in-ring TOF and position measurements,beam-line TOF measurements at two achromatic foci, and position measurements at a dispersive focus of HFRS, thus making it possible to use two complementary mass measurement methods [isochronous mass spectrometry at the storage ring SRing and magnetic-rigidity–time-of-flight(Bρ-TOF) at the beam-line HFRS] in one single experimental run. 相似文献
43.
基于声发射和高斯混合模型的灰岩破裂特征识别研究 总被引:3,自引:0,他引:3
通过单轴压缩条件下灰岩破裂过程的声发射试验研究,利用高斯混合模型(GMM)对加载过程声发射信号波形特征进行深入分析,探索性识别灰岩破裂失稳过程的裂纹模式及其前兆特征。分析结果表明,灰岩在单轴加载过程中先后主要存在张拉和剪切两种破裂模式。其中,张拉破裂的声发射信号波形特征在AF-RA坐标空间呈现低A_F值、高R_A值分布;剪切破裂的声发射信号波形特征在AF-RA坐标空间呈现低R_A值、高A_F值,且随着应力的增加分布中心向A_F轴靠拢。GMM分析结果揭示了灰岩在整个应力加载过程中以张拉裂纹为主,在加载前中期几乎全为张拉裂纹,临近破坏阶段过渡到剪切破坏为主。剪切裂纹所占比例的最大值出现在(0.8~0.9)σ_c阶段,也是AF-RA坐标轴分布呈现最大A_F值时。研究结果可为预测早期灰岩破裂失稳提供参考,同时为深入研究识别岩石破裂失稳前兆信号特征提供了一种分析方法。 相似文献
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45.
Wang Lu-di Zhou Wei Xing Ying Liu Na Movahedipour Mahmood Zhou Xiao-guang 《浙江大学学报:C卷英文版》2019,20(3):405-413
Frontiers of Information Technology & Electronic Engineering - Reconstruction of a 12-lead electrocardiogram (ECG) from a serial 3-lead ECG has been researched in the past to satisfy the need... 相似文献
46.
Shuai Wang Yangyang Deng Shuaibo Gao Mingsheng Yang Pengfei Xing 《International Journal of Applied Ceramic Technology》2020,17(6):2569-2579
B4C-TiB2-SiC composites toughened by (TiB2-SiC) agglomerates were prepared via reactive hot pressing with B4C and TiSi2 as raw materials. Phase composition, microstructure, and mechanical properties of the fabricated composites were investigated. The function of (TiB2-SiC) agglomerates was analyzed, and the strengthening and toughening mechanism were also discussed. Results indicated that some of the in situ formed TiB2 and SiC were interlocked to form special (TiB2-SiC) agglomerates in the matrix. The good comprehensive performances of 510 MPa flexural strength, 5.84 MPa·m1/2 fracture toughness, and 31.93 GPa hardness were obtained in the composites fabricated with 30 wt% TiSi2. The in situ introduced fine TiB2 and SiC grains refined the grains of B4C due to the pinning effect, which enhanced the strength. The special (TiB2-SiC) agglomerates and the existing toughening phenomena such as crack deflection, branching, and microcrack regions induced by the mismatch of thermal expansion coefficients, had cumulative effects on improving the fracture toughness. 相似文献
47.
采用单辊甩带法制备了厚度为0.03 mm的6.5%Si极薄带,并在真空炉中进行了880 ℃和920 ℃的退火处理。利用XRD和EBSD研究了其在退火后的宏观和微观织构演变规律。结果表明:经单辊甩带制得的6.5%Si极薄带织构主要由{001}<100>立方织构、{110}<001> Goss织构和{112}<111>织构组成。随着退火温度的升高,λ纤维仍占主导地位,且晶粒尺寸逐渐增大。特别是在920 ℃退火时,{001}<120>和{001}<100>晶粒的尺寸优势逐渐增大,不利织构{111}<110>和{111}<112>逐渐减弱,且最终的磁感应强度B50=1.644 T,铁损耗P10/400=5.896 W/kg。 相似文献
48.
Injection of bionic synovial fluid (BSF) is a conventional method to improve the lubricity of artificial joints, but BSF cannot maintain long due to the dilution and degradation of BSF in human body. To prolong the effectiveness of hyaluronic acid (HA), which is the major component of BSF, this study applies a temperature‐sensitive poly(?‐caprolactone)–poly(ethylene glycol)–poly(?‐caprolactone) (PCEC) hydrogel loaded with HA to achieve long‐term lubrication. In addition, Fourier transform infrared, nuclear magnetic resonance analysis, X‐ray diffraction, scanning electron microscopy (SEM), and gel permeation chromatography spectra were used to analyze the structure of the synthetic hydrogel. Rheological test and test tube inverting method were used to characterize the thermosensitivity. The lubrication properties of the released solution were characterized by UV–vis, tribological tests, SEM, and 3D laser confocal scanning microscope. The experimental results reveal that the triblock PCEC hydrogel contains both hydrophilic block and hydrophobic block, and both PCEC and PCEC/HA hydrogels have phase‐changed effect when the temperature increases from room temperature to body temperature. Moreover, the friction coefficient of the released solution from PCEC/HA hydrogel is approximatively 38% lower than that of phosphate buffer saline. And the ability of shear resistance and creep recovery of PCEC/HA hydrogel are better than that of PCEC hydrogel. This study provides an effective approach to achieve long‐time lubrication effect for artificial joints. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46228. 相似文献
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