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噪声 2

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珊瑚岛礁环境噪声成像 Article

夏少红, 张昌榕, 曹敬贺

《工程（英文）》 2023年 第25卷 第6期   页码 182-193 doi: 10.1016/j.eng.2021.09.022

摘要：

As valuable land in the ocean, coral islands are not only important bases for making use of marine resources and protecting marine rights and interests, but also important for breakthrough research in many fields of earth science. Hence, the economical and efficient determination of the underground structure of coral islands has become significant in coral island engineering geology, but remains challenging for traditional marine geophysical prospecting and drilling methods. While ambient noise tomography with dense arrays has been widely used in continental regions, its applicability to coral islands remains undetermined. In this study, based on the data recorded by a dense array on an isolated coral island in the South China Sea, we analyzed the ambient noise characteristics and obtained a 3D subsurface structure of the coral island using ambient noise tomography. We made the following findings: ① The ambient noise frequencies can be roughly categorized into three levels: < 1, 1–5, and > 5 Hz. The spectral characteristics of the noise below 5 Hz were consistent at different stations, but there were significant differences in the characteristics of the noise above 5 Hz. ② For ambient noise frequencies below 5 Hz, cross-correlation functions with high quality could be obtained with only 24 h of waveform data. However, it was difficult to extract meaningful cross-correlation functions for ambient noise frequencies above 5 Hz. ③ The S-wave velocity in the coral island was higher toward the sea and lower toward the lagoon, which was consistent with the high degree of cementation of the outer reef flat stratum on the seaward side. ④ There were two low-velocity horizons at 25–75 and 200–300 m, which were in good agreement with the high-porosity horizons that were revealed by drilling core samples, reflecting the weathering history of the reef. Our research demonstrates that ambient noise tomography is a potentially economical, efficient, and environmentally friendly method for the geological prospecting of coral reefs.

关键词： Coral island     Ambient noise tomography     Engineering geology     South China Sea    

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iterative data enhancement for implementation in purification of modal frequency for extremely noisy ambient

Hassan YOUSEFI, Alireza TAGHAVI KANI, Iradj MAHMOUDZADEH KANI, Soheil MOHAMMADI

《结构与土木工程前沿（英文）》 2020年 第14卷 第2期   页码 446-472 doi: 10.1007/s11709-019-0605-8

摘要： The main purpose of the present study is to enhance high-level noisy data by a wavelet-based iterative filtering algorithm for identification of natural frequencies during ambient wind vibrational tests on a petrochemical process tower. Most of denoising methods fail to filter such noise properly. Both the signal-to-noise ratio and the peak signal-to-noise ratio are small. Multiresolution-based one-step and variational-based filtering methods fail to denoise properly with thresholds obtained by theoretical or empirical method. Due to the fact that it is impossible to completely denoise such high-level noisy data, the enhancing approach is used to improve the data quality, which is the main novelty from the application point of view here. For this iterative method, a simple computational approach is proposed to estimate the dynamic threshold values. Hence, different thresholds can be obtained for different recorded signals in one ambient test. This is in contrast to commonly used approaches recommending one global threshold estimated mainly by an empirical method. After the enhancements, modal frequencies are directly detected by the cross wavelet transform (XWT), the spectral power density and autocorrelation of wavelet coefficients. Estimated frequencies are then compared with those of an undamaged-model, simulated by the finite element method.

关键词： ambient vibration test     high level noise     iterative signal enhancement     wavelet     cross and autocorrelation of wavelets    

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Multislice computed tomography angiography in the diagnosis of cardiovascular disease: 3D visualizations

Zhonghua Sun

《医学前沿（英文）》 2011年 第5卷 第3期   页码 254-270 doi: 10.1007/s11684-011-0153-7

摘要： Multislice computed tomography (CT) has been widely used in clinical practice for the diagnosis of cardiovascular disease due to its reduced invasiveness and high spatial and temporal resolution. As a reliable alternative to conventional angiography, multislice CT angiography has been recognized as the method of choice for detecting and diagnosing head and neck vascular disease, abdominal aortic aneurysm, aortic dissection, and pulmonary embolism. In patients with suspected coronary artery disease, although invasive coronary angiography still remains as the gold standard technique, multislice CT angiography demonstrates high diagnostic accuracy; in selected patients, it is considered as the first-line technique. The imaging diagnosis of cardiovascular disease is based on a combination of two-dimensional (2D) and three-dimensional (3D) visualization tools to enhance the diagnostic value. This is facilitated by reconstructed visualizations which provide additional information about the extent of the disease, an accurate assessment of the spatial relationship between normal structures and pathological changes, and pre-operative planning and post-procedure follow-up. The aim of the present article is to present an overview of the diagnostic performance of various 2D and 3D CT visualizations in cardiovascular disease, including multiplanar reformation, maximum intensity projection, volume rendering, and virtual intravascular endoscopy. The recognition of the potential value of these visualizations will assist clinicians in efficiently using the multislice CT imaging modality for the diagnostic management of patients with cardiovascular disease.

关键词： cardiovascular disease     multislice computed tomography     three-dimensional reconstruction     diagnosis     visualization    

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Prediction of the theoretical and semi-empirical model of ambient temperature

Foued CHABANE,Noureddine MOUMMI,Abdelhafid BRIMA,Abdelhafid MOUMMI

《能源前沿（英文）》 2016年 第10卷 第3期   页码 268-276 doi: 10.1007/s11708-016-0413-y

摘要： It is well known that the ambient temperature is a sensitive parameter which has a great effect on biology, technology, geology and even on human behavior. A prediction is a statement about an uncertain event. It is often, but not always, based upon experience or knowledge. Although guaranteed accurate information about the future is in many cases impossible, prediction can be useful to assist in making plans about possible developments. As a result, temperature profiles can be developed which accurately represent the expected ambient temperature exposure that this environment experiences during measurement. The ambient temperature over time is modeled based on the previous and data and using a Lagrange interpolation. To observe the comprehensive variation of ambient temperature the profile must be determined numerically. The model proposed in this paper can provide an acceptable way to measure the change in ambient temperature.

关键词： ambient temperature     environment     correlation     theoretical model     semi-empirical    

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Human health ambient water quality criteria for 13 heavy metals and health risk assessment in Taihu Lake

《环境科学与工程前沿（英文）》 2022年 第16卷 第4期 doi: 10.1007/s11783-021-1475-6

摘要：

• The concentrations of 13 heavy metals in Taihu Lake were analyzed.

关键词： Heavy metals     Human health ambient water quality criteria     Taihu Lake     Health risk assessment     Contribution rate    

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Chemisorption solid materials for hydrogen storage near ambient temperature: a review

Yiheng ZHANG, Shaofei WU, Liwei WANG, Xuefeng ZHANG

《能源前沿（英文）》 2023年 第17卷 第1期   页码 72-101 doi: 10.1007/s11708-022-0835-7

摘要： Solid chemisorption technologies for hydrogen storage, especially high-efficiency hydrogen storage of fuel cells in near ambient temperature zone defined from −20 to 100°C, have a great application potential for realizing the global goal of carbon dioxide emission reduction and vision of carbon neutrality. However, there are several challenges to be solved at near ambient temperature, i.e., unclear hydrogen storage mechanism, low sorption capacity, poor sorption kinetics, and complicated synthetic procedures. In this review, the characteristics and modification methods of chemisorption hydrogen storage materials at near ambient temperature are discussed. The interaction between hydrogen and materials is analyzed, including the microscopic, thermodynamic, and mechanical properties. Based on the classification of hydrogen storage metals, the operation temperature zone and temperature shifting methods are discussed. A series of modification and reprocessing methods are summarized, including preparation, synthesis, simulation, and experimental analysis. Finally, perspectives on advanced solid chemisorption materials promising for efficient and scalable hydrogen storage systems are provided.

关键词： hydrogen storage capacity     chemisorption     near-ambient-temperature     modification methods     alloy hydrides    

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Hygroscopicity of ambient submicron particles in urban Hangzhou, China

Jiachen ZHANG, Lin WANG, Jianmin CHEN, Shengmao FENG, Jiandong SHEN, Li JIAO

《环境科学与工程前沿（英文）》 2011年 第5卷 第3期   页码 342-347 doi: 10.1007/s11783-011-0358-7

摘要： In this study, hygroscopicity of size-segregated ambient submicron particles in urban Hangzhou was studied from 28th December 2009 to 18th January 2010, using a hygroscopicity-tandem differential mobility analyzer (H-TDMA). The submicron particles in Hangzhou showed a minor hygroscopic growth at 73% relative humidity (RH), and then grew significantly between 77% and 82% RH. Monomodal distribution accounted for 90% for 30 nm particles, 17% for 50 nm particles, and less than 7% for particles larger than 50 nm at 82% RH. Deconvolution of the bimodal distribution indicated a less hygroscopic group and a more hygroscopic group, with the fraction of the more hygroscopic group increasing with the initial dry particle size and then remaining almost constant for accumulation mode particles. Our results imply that submicron particles in urban Hangzhou were almost entirely externally mixed, and the hygroscopic properties of ambient particles in urban Hangzhou were mainly a function of their size and chemical composition.

关键词： hygroscopicity     hygroscopic tandem differential mobility analyzer (H-TDMA)     submicron ambient particles     Hangzhou    

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Effect of ambient polycyclic aromatic hydrocarbons and nicotine on the structure of Aβ protein

《环境科学与工程前沿（英文）》 2023年 第17卷 第2期 doi: 10.1007/s11783-023-1615-2

摘要：

● B[a]P, nicotine and phenanthrene molecules altered the secondary structure of Aβ42.

关键词： Polycyclic aromatic hydrocarbons     Nicotine     toxicology     Aβ42 peptide     Alzheimer’s disease     Molecular dynamics simulations     Environmental pollution    

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Design of noise-reduction seats for high-speed trains

Xiaojun DENG, Yanju ZHAO, Haijin ZHANG, Renzhong SHUAI, Leiwei ZHU

《机械工程前沿（英文）》 2018年 第13卷 第3期   页码 385-389 doi: 10.1007/s11465-017-0438-x

摘要：

Noise-reduction seats have been successfully used in concert halls, theaters, and other places that reduce noise. In this study, a new noise-reduction seat design was proposed for high-speed trains, which have unique interior noise spectral characteristics. First, before the noise-reduction seat models were fabricated, the parameters of high-performance sound-absorbing materials and perforated plates were selected by conducting a standing-wave tube test. The sound-absorption effects of the noise-reduction seats and normal seats were investigated and compared in a reverberation chamber. Test results showed that, compared with normal seats, the noise-reduction seats obtained a significantly improved sound-absorption coefficient in the entire frequency band. Furthermore, the test results were used to establish a simulation model for calculation, and the simulation results proved that the noise-reduction seats substantially reduced the noise in an entire train car. Finally, the noise-reduction seats were fabricated and installed in a full train car of an actual high-speed train. The test results showed that, compared with the normal seats, the noise-reduction seats decreased the noise level at a standard point in the passenger car by 1.5 dB. Therefore, the noise-reduction seats are effective in noise reduction.

关键词： high-speed train     sound-absorbing materials     perforated board     noise-reduction seats    

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of plotting sensor sensitivity field and image reconstruction algorithm for electrical capacitance tomography

CHEN De-yun, YANG Cong-jing, ZHENG Gui-bin, YU Xiao-yang, SUN Li-juan

《机械工程前沿（英文）》 2006年 第1卷 第2期   页码 242-247 doi: 10.1007/s11465-006-0008-0

摘要： Sensor sensitivity field in electrical capacitance tomography is affected by the distribution of multiphase medium, which is the peculiarity of soft field. This brings great difficulty for image reconstruction. To improve the quality of image reconstruction, it is important to analyze the distribution of the sensitivity field. In this article, using the finite element method, we expound a kind of novel plotting pattern to field, which is the distribution of sensitivity field through computer simulation. From experiments and results of sensitivity field analysis, a novel method of image reconstruction based on genetic algorithms is presented. The finite element model is correct and simulation result is fine by adopting unequal interval plotting patterns. At the same time, the result of image reconstruction has high precision.

关键词： multiphase     unequal interval     capacitance tomography     pattern     sensitivity    

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Effect of sodium bicarbonate solution on methyltrimethoxysilane-derived silica aerogels dried at ambient

Yujing Liu, Xiao Han, Balati Kuerbanjiang, Vlado K. Lazarov, Lidija Šiller

《化学科学与工程前沿（英文）》 2021年 第15卷 第4期   页码 954-959 doi: 10.1007/s11705-020-2028-4

摘要： Here we present an economical ambient pressure drying method of preparing monolithic silica aerogels from methyltrimethoxysilane precursor while using sodium bicarbonate solution as the exchanging solvent. We prepared silica aerogels with a density and a specific surface area of 0.053 g∙cm and 423 m ∙g , respectively. The average pore diameter of silica aerogels is 23 nm as the pore specific volume is 1.11 cm ∙g . Further, the contact angle between water droplet and the surface of silica aerogels in specific condition can be as high as 166°, which indicates a super-hydrophobic surface of aerogels.

关键词： silica aerogel     methyltrimethoxysilane     solvent exchange     sodium bicarbonate     trimethylchlorosilane     ambient pressure drying    

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Hybrid energy harvesting systems for self-powered sustainable water purification by harnessing ambient

《环境科学与工程前沿（英文）》 2023年 第17卷 第10期 doi: 10.1007/s11783-023-1718-9

摘要：

● Energy harvesters harness multiple energies for self-powered water purification.

关键词： Piezocatalysis     Solar energy     Waste heat     Decentralized water treatment     Point-of-use     Nanogenerator    

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Experimental study of modal parameter identification in a simulated ambient-excited structure

JI Xiaodong, QIAN Jiaru, XU Longhe

《结构与土木工程前沿（英文）》 2007年 第1卷 第3期   页码 281-285 doi: 10.1007/s11709-007-0036-9

摘要： Structure modal parameter online identification was used to monitor the structural health as evidenced by changes in the vibration characteristics. The natural excitation technique and the eigensystem realization algorithm were combined to identify the modal parameters in the time domain of a structure excited by simulated ambient vibrations. The mass-normalized mode shapes were obtained from the eigen-sensitivity analysis. The experimental modal analysis was performed on a two-story steel braced frame model excited by simulated ambient vibrations and hammer impacts. The mass-normalized mode shapes were acquired by changing the structural mass and by eigen-sensitivity analy sis. From finite element analysis results and the experimental data, it is shown that this method is effective.

关键词： eigensystem realization     eigen-sensitivity analysis     realization algorithm     vibration     effective    

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Evaluating the short-term effect of ambient temperature on non-fatal outdoor falls and road traffic injuries

《环境科学与工程前沿（英文）》 2023年 第17卷 第9期 doi: 10.1007/s11783-023-1705-1

摘要：

● A study assessing the temperature-injury relationship was conducted among students.

关键词： Ambient temperature     Fall     Road traffic injury     Student     China    

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Single particle analysis of ambient aerosols in Shanghai during the World Exposition, 2010: two case

Shikang TAO, Xinning WANG, Hong CHEN, Xin YANG, Mei LI, Lei LI, Zhen ZHOU

《环境科学与工程前沿（英文）》 2011年 第5卷 第3期   页码 391-401 doi: 10.1007/s11783-011-0355-x

摘要： A TSI Model 3800 aerosol time-of-flight mass spectrometer (ATOFMS) was deployed for single-particle analysis in Shanghai during the World Exposition (EXPO), 2010. Measurements on two extreme cases: polluted day (1st May) and clean day (25th September) were compared to show how meteorological conditions affected the concentration and composition of ambient aerosols. Mass spectra of 90496 and 50407 particles were analyzed respectively during the two sampling periods. The ART-2a neural network algorithm was applied to sort the collected particles. Seven major classes of particles were obtained: dust, sea salt, industrial, biomass burning, organic carbon (OC), elementary carbon (EC), and NH -rich particles. Number concentration of ambient aerosols showed a strong anti-correlation with the boundary layer height variation. The external mixing states of aerosols were quite different during two sampling periods because of different air parcel trajectories. Number fraction of biomass burning particles (43.3%) during polluted episode was much higher than that (21.6%) of clean time. Air parcels from the East China Sea on clean day diluted local pollutant concentration and increased the portion of sea salt particle dramatically (13.3%). The large contribution of biomass burning particles in both cases might be an indication of a constant regional background of biomass burning emission. Mass spectrum analysis showed that chemical compositions and internal mixing states of almost all the particle types were more complicate during polluted episode compared with those observed in clean time. Strong nitrate signals in the mass spectra suggested that most of the particles collected on polluted day had gone through some aging processes before reaching the sampling site.

关键词： ambient aerosol     aerosol time-of-flight mass spectrometer     Shanghai     world exposition    

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标题 作者 时间 类型 操作

珊瑚岛礁环境噪声成像

夏少红, 张昌榕, 曹敬贺

期刊论文

iterative data enhancement for implementation in purification of modal frequency for extremely noisy ambient

Hassan YOUSEFI, Alireza TAGHAVI KANI, Iradj MAHMOUDZADEH KANI, Soheil MOHAMMADI

期刊论文

Multislice computed tomography angiography in the diagnosis of cardiovascular disease: 3D visualizations

Zhonghua Sun

期刊论文

Prediction of the theoretical and semi-empirical model of ambient temperature

Foued CHABANE,Noureddine MOUMMI,Abdelhafid BRIMA,Abdelhafid MOUMMI

期刊论文

Human health ambient water quality criteria for 13 heavy metals and health risk assessment in Taihu Lake

期刊论文

Chemisorption solid materials for hydrogen storage near ambient temperature: a review

Yiheng ZHANG, Shaofei WU, Liwei WANG, Xuefeng ZHANG

期刊论文

Hygroscopicity of ambient submicron particles in urban Hangzhou, China

Jiachen ZHANG, Lin WANG, Jianmin CHEN, Shengmao FENG, Jiandong SHEN, Li JIAO

期刊论文

Effect of ambient polycyclic aromatic hydrocarbons and nicotine on the structure of Aβ protein

期刊论文

Design of noise-reduction seats for high-speed trains

Xiaojun DENG, Yanju ZHAO, Haijin ZHANG, Renzhong SHUAI, Leiwei ZHU

期刊论文

of plotting sensor sensitivity field and image reconstruction algorithm for electrical capacitance tomography

CHEN De-yun, YANG Cong-jing, ZHENG Gui-bin, YU Xiao-yang, SUN Li-juan

期刊论文

Effect of sodium bicarbonate solution on methyltrimethoxysilane-derived silica aerogels dried at ambient

Yujing Liu, Xiao Han, Balati Kuerbanjiang, Vlado K. Lazarov, Lidija Šiller

期刊论文

Hybrid energy harvesting systems for self-powered sustainable water purification by harnessing ambient

期刊论文

Experimental study of modal parameter identification in a simulated ambient-excited structure

JI Xiaodong, QIAN Jiaru, XU Longhe

期刊论文

Evaluating the short-term effect of ambient temperature on non-fatal outdoor falls and road traffic injuries

期刊论文

Single particle analysis of ambient aerosols in Shanghai during the World Exposition, 2010: two case

Shikang TAO, Xinning WANG, Hong CHEN, Xin YANG, Mei LI, Lei LI, Zhen ZHOU

期刊论文