检索结果-南通市图书馆

A reweighted damped singular spectrum analysis method for robust seismic noise suppression

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2024年第3期21卷 1671-1682页

作者： wei-Lin Huang Yan-Xin Zhou Yang Zhou wei-jie Liu Ji-Dong Li State Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing2249China SINOPEC Petroleum Exploration and Production Research Institute Beijing102206China SINOPEC Geophysical Research Institute Nanjing211103jiangsuChina

(Multichannel)Singular spectrum analysis is considered as one of the most effective methods for seismic incoherent noise *** utilizes the low-rank feature of seismic signal and regards the noise suppression as a low-rank reconstruction ***,in some cases the seismic geophones receive some erratic disturbances and the amplitudes are dramatically larger than other *** presence of this kind of noise,called erratic noise,makes singular spectrum analysis(SSA)reconstruction unstable and has undesirable effects on the final *** robustify the low-rank reconstruction of seismic data by a reweighted damped SSA(RD-SSA)*** incorporates the damped SSA,an improved version of SSA,into a reweighted *** damping operator is used to weaken the artificial disturbance introduced by the low-rank projection of both erratic and random *** central idea of the RD-SSA method is to iteratively approximate the observed data with the quadratic norm for the first iteration and the Tukeys bisquare norm for the rest *** RD-SSA method can suppress seismic incoherent noise and keep the reconstruction process robust to the erratic *** feasibility of RD-SSA is validated via both synthetic and field data examples.

关键词： Singular spectrum analysis Damping operator Seismic erratic noise Seismic signal processing Robust low-rank reconstruction

Microstructure and impact behavior of Mg-4Al-5RE-xGd cast magnesium alloys

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2024年第5期12卷 1799-1814页

作者： jie wei Qudong Wang Huisheng Cai Mahmoud Ebrahimi Chuan Lei National Engineering Research Center of Light Alloy Net Forming and Key State Laboratory of Metal Matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China

This work investigated the microstructure and impact behavior of Mg-4Al-5RE-xGd(RE represents La-Ce mischmetal;x=0,0.2,0.7 wt.%)alloys cast by high-pressure die casting(HPDC),permanent mold casting(PMC),and sand casting(SC)*** results indicated that with increasing Gd content,the grain sizes of the HPDC alloy had a slight change,but the grains of the PMC and SC alloys were significantly ***,the acicular Al_(11)RE_(3)phase was modified into the short-rod shape under the three casting *** impact toughness of the studied alloy was mainly dominated by the absorbed energy during the crack *** increasing Gd content,the impact toughness of the studied alloy monotonically increased due to the lower tendency of the modified second phase toward crack *** impact stress was higher than the tensile stress,exhibiting a strain rate sensitivity for the mechanical response;however,the HPDC alloy had an inconsistent strain rate sensitivity during the impact event due to the transformation of the deformation mechanism from twinning to slip with increasing *** dimples covered the fracture surface of the fine-grained HPDC alloys,indicating a typical ductile ***,due to the deficient{1012}twinning activity and the suppressed grain boundary sliding during the impact event,the HPDC alloys showed insufficient plastic deformation capacity.

关键词： Mg-Al-RE alloy Gadolinium Microstructure Impact behavior

New Vacuum Solar Telescope Achieves Narrowband Infrared Solar Imaging Observation at He I 10830 A

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2024年第5期24卷 76-84页

作者： wei-jie Meng Fang-Yu Xu Zhen-Yu Jin Yunnan Observatories Chinese Academy of SciencesKunming 650011China Yunnan Key Laboratory of Solar Physics and Space Science Kunming 650216China University of Chinese Academy of Sciences Beijing 100049China

The near-infrared imaging channel constitutes a crucial component of the multichannel high-resolution imaging system of the New Vacuum Solar Telescope(NVST). We have successfully achieved high-resolution, narrowband imaging of the chromosphere using He I 10830 A triplet within this channel, which significantly enhances the imaging observation capabilities of NVST. This paper provides a concise overview of the optical system associated with the near-infrared imaging channel, detailing data processing procedures and presenting several observed images. Leveraging a high-resolution image reconstruction algorithm, we were able to generate a narrowband image near the diffraction limit at 10830 A with a temporal resolution of less than 10 s.

关键词： instrumentation detectors-instrumentation high angular resolution-Sun chromosphere-Sun infrared

Fluorescent carbon dots synthesized in solid phase and air for application in LEDs

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第9期17卷 8495-8503页

作者： wei-jie Zheng Zhao-Nan Sun Yi-Ming Wang Huan-Ming Xiong Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials Fudan UniversityShanghai 200438China

Carbon dots(CDs)have been widely adopted as optical materials because of their excellent luminescent ***,most of the reported synthetic methods are conducted in solvents,especially hydrothermal/solvothermal reactions,leading to intractable problems such as toxic and flammable solvents,complex and inseparable by-products,and dangerously high pressures and ***-phase synthesis of CDs in air is an effective solution to overcome the above issues,but solid reactions always result in uncontrolled growth and agglomeration of *** this study,some inorganic salts are selected as catalysts for synthesizing CDs in solid states and air,which also play as dispersants to hinder CDs *** the meantime,some aromatic derivatives containing hydroxyl and amino groups are chosen as carbon sources,ground with the optimized catalyst,and then heated together in *** production yields are affected by the reaction time and reactant ratio,while the graphitization degrees of the CDs are determined by the reaction *** IG/ID value of their Raman spectra increases from 0.59 to 0.85,and the particle size decreases from 2.5 to 1.4 nm when the synthesis temperature is increased from 200 to 280℃.The as-prepared CDs show emission peaks ranging from 366 to 606 nm,with the photoluminescence(PL)quantum yield up to 53%.Their emission color variation mainly results from different carbon sources,which can be ascribed to the differences in the element composition,functional groups,and graphitic nitrogen content of these *** dispersing CDs of different concentrations into polyvinyl alcohol(PVA)and combining them with blue LEDs,cold,standard,and warm white light emitting devices(WLEDs)are prepared,with a color rendering index(CRI)up to *** the as-prepared CDs have antioxidant ability at high temperature,the as-prepared WLEDs have long lifespans,remaining the effective white luminescence after 72 h continuous work.

关键词： carbon dot solid-phase synthesis white LED photoluminescence inorganic salt catalysis

Life cycle assessment of homogeneous Fenton process as pretreatment for refractory pharmaceutical wastewater

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Chemical Science and Engineering 2024年第5期18卷 1-11页

作者： Maojun Zou jie wei Yuanyuan Qian Yanjing Xu Zhihuang Fang Xuejing Yang Zhiyuan Wang School of Energy and Power Engineering University of Shanghai for Science and TechnologyShanghai 200093China Shanghai Engineering Laboratory of Lean Operational Technologies for Full Water System East China University of Science and TechnologyShanghai 200237China Mcwong Environmental Technology Company Limited Shanghai 200135China National Engineering Laboratory of High Concentration and Refractory Organic Wastewater Treatment Technology East China University of Science and TechnologyShanghai 200237China

The applicability of the life cycle assessment(LCA)to the Fenton process should be considered not only at the laboratory-scale but also at the *** this study,the LCA process was applied to evaluate the homo-geneous Fenton process for the treatment of high salinity pharmaceutical *** potential environmental impacts were calculated using Simapro software implemen-ting the CML 2001 methodology with normalization factors of 1995 *** data obtained directly from the full-scale wastewater treatment plant and labora-tory were used to conduct a life cycle inventory analysis,ensuring highly accurate *** normalized results,the Fenton process reveals sensitive indicators,primarily toxi-city indicators(human toxicity,freshwater aquatic toxicity,and marine aquatic toxicity),as well as acidification and eutrophication impacts,contributed by hydrogen peroxide and iron sludge incineration,***,hydrogen peroxide and iron sludge incineration contribute significantly,accounting for at least 78%of these *** sludge treatment phase,treatment of iron mud and infrastructure of hazardous waste incineration plants were the key contributors of environmental impacts,adding up to more than 95%.This study suggests the need to develop efficient oxidation processes and effective iron sludge treatment methods to reduce resource utilization and improve environmental benefits.

关键词： advanced oxidation processes full-scale life cycle assessment Fenton process pharmaceutical high-salinity wastewater

Study of baryon number transport dynamics and strangeness conservation effects using Ω-hadron correlations

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2024年第7期35卷 147-156页

作者： wei-jie Dong Xiao-Zhou Yu Si-Yuan Ping Xia-Tong Wu Gang Wang Huan-Zhong Huang Zi-wei Lin Key Laboratory of Nuclear Physics and Ion-beam Application(MOE) Fudan UniversityShanghai 200433China Department of Physics and Astronomy University of CaliforniaLos AngelesCA 90095USA Department of Physics East Carolina UniversityGreenvilleNC 27858USA

In nuclear collisions at RHIC energies, an excess of Ω hyperons over ■ is observed, indicating that Ω has a net baryon number despite s and s quarks being produced in pairs. The baryon number in Ω may have been transported from the incident nuclei and/or produced in the baryon-pair production of Ω with other types of anti-hyperons such as Ξ. To investigate these two scenarios, we propose to measure the correlations between Ω and K and between Ω and anti-hyperons. We use two versions, the default and string-melting, of a multiphase transport(AMPT) model to illustrate the method for measuring the correlation and to demonstrate the general shape of the correlation. We present the Ω-hadron correlations from simulated Au+Au collisions at ■ =7.7 and 14.6 Ge V and discuss the dependence on the collision energy and on the hadronization scheme in these two AMPT versions. These correlations can be used to explore the mechanism of baryon number transport and the effects of baryon number and strangeness conservation on nuclear collisions.

关键词： Baryon number transport Strangeness conversation Correlation Gluon junction

Multiple damage zones around hydraulic fractures generated by high-frequency pulsating hydraulic fracturing

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2024年第4期21卷 2688-2702页

作者： Yan Peng Sheng-jie wei Guang-Qing Zhang Da-wei Zhou Chuang-Chao Xu School of Petroleum Engineering China University of Petroleum PetroChina Changqing Oilfield Company

Pulsating hydraulic fracturing(PHF) is a promising fracturing method and can generate a dynamic periodic pressure. The periodic pressure can induce fatigue failure of rocks and decrease initiation pressure of fracture. If the frequency of periodic pressure exceeds 10 Hz, the distribution of pressure along the main fracture will be heterogeneous, which is much different from the one induced by the common fracturing method. In this study, the impact of this special spatial feature of pressure on hydraulic fracture is mainly investigated. A coupled numerical simulation model is first proposed and verified through experimental and theoretical solutions. The mechanism of secondary fracture initiation around the main fracture is then discovered. In addition, sensitivity studies are conducted to find out the application potential of this new method. The results show that(1) this coupled numerical simulation model is accurate. Through comparison with experimental and theoretical data, the average error of this coupled model is less than 1.01%.(2) Even if a reservoir has no natural fracture, this heterogeneous distribution pressure can also cause many secondary fractures around the main fracture.(3) The mechanism of secondary fracture initiation is that this heterogeneous distribution pressure causes tensile stress at many locations along the main fracture.(4) Through adjusting the stimulation parameters, the stimulation efficiency can be improved. The average and amplitude of pressure can increase possibility of secondary fracture initiation. The frequency of this periodic pressure can increase number of secondary fractures. Even 6 secondary fractures along a 100 m-length main fracture can be generated.(5) The influence magnitudes of stimulation parameters are larger than ones of geomechanical properties, therefore, this new fracturing method has a wide application potential.

关键词： Tight reservoir Reservoir stimulation Numerical simulation Secondary fracture Fracture initiation

Biological factors driving colorectal cancer metastasis

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastrointestinal Oncology 2024年第2期16卷 259-272页

作者： Shuai-Xing An Zhao-Jin Yu Chen Fu Min-jie wei Long-Hai Shen Department of Pharmacology School of PharmacyChina Medical UniversityShenyang 110122Liaoning ProvinceChina Liaoning Key Laboratory of Molecular Targeted Antitumor Drug Development and Evaluation Liaoning Cancer Immune Peptide Drug Engineering Technology Research CenterKey Laboratory of Precision Diagnosis and Treatment of Gastrointestinal Tumors(China Medical University)Ministry of EducationShenyang 110122Liaoning ProvinceChina BD Department Greenpine Pharma Group Co.LtdTianjin 300020China Center of Oncology Genertec Liaoyou Gem Flower HospitalPanJin 124010Liaoning ProvinceChina

Approximately 20%of colorectal cancer(CRC)patients present with metastasis at *** Stage I-III CRC patients who undergo surgical resection,18%typically suffer from distal metastasis within the first three years following initial *** median survival duration after the diagnosis of metastatic CRC(mCRC)is only 9 *** is traditionally considered to be an advanced stage malignancy or is thought to be caused by incomplete resection of tumor tissue,allowing cancer cells to spread from primary to distant organs;however,increa-sing evidence suggests that the mCRC process can begin early in tumor *** patients present with high heterogeneity and diverse cancer phenotypes that are classified on the basis of molecular and morphological *** genomic and nongenomic events can induce subclone diversity,which leads to cancer and *** the course of mCRC,metastatic cascades are associated with invasive cancer cell migration through the circulatory system,extravasation,distal seeding,dormancy,and reactivation,with each step requiring specific molecular ***,cancer cells presenting neoantigens can be recognized and eliminated by the immune *** this review,we explain the biological factors that drive CRC metastasis,namely,genomic instability,epigenetic instability,the metastatic cascade,the cancer-immunity cycle,and external lifestyle *** remarkable progress in CRC research,the role of molecular classification in therapeutic intervention remains *** review shows the driving factors of mCRC which may help in identifying potential candidate biomarkers that can improve the diagnosis and early detection of mCRC cases.

关键词： cancer Metastasis cascade Cancer immunity Genomic variation Epigenetic instability Lifestyle factor

Features and formulae of sediment incipient motion in vegetated flow environment

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2024年第2期36卷 331-339页

作者： Yu-xuan Xu wei-jie Wang Shi-bao Zhang Han-qing Zhao Xue-kai Chen Hai-ping Zhang School of Water Conservancy North China University of Water Resources and Electric PowerZhengzhou450045China State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijing100038China China Three Gorges Corporation Wuhan430010China

Aquatic vegetation is a vital component of natural river ecosystems,playing a crucial role in maintaining ecological balance,providing habitat and improving water ***,the presence of vegetation results in increased resistance in vegetated channels compared with non-vegetated channels,rendering traditional sediment movement predictions inadequate for the ***,the concept of a vegetation influence factor,denoted by CDah,has been proposed by previous researchers to represent the effect of vegetation on sediment movement in *** this study,we focus on exploring the vegetation resistance coefficient(CD)among the vegetation influence factors,evaluating two different calculation methods for vegetation resistance coefficient,and presenting two expressions through genetic algorithm analysis to predict the incipient flow velocity of sediment in vegetated *** predicted values from the new formulae show excellent agreement with measured data,highlighting the high accuracy of the proposed methods in predicting the incipient flow velocity of *** results provide a solid theoretical basis for understanding the influence of aquatic vegetation on sediment particle movement.

关键词： Vegetation flow vegetation resistance coefficient genetic algorithm sediment initiation