期刊文献+
共找到8,322篇文章
< 1 2 250 >
每页显示 20 50 100
The Coevolutionary Relationship of Technology, Market and Government Regulation in Telecommunications 被引量:1
1
作者 Xuchen Lin Ting-Jie Lv Xia Chen 《China Communications》 SCIE CSCD 2018年第8期152-173,共22页
The telecommunications industry has been undergoing tremendous technological changes, and owning to continuous technological advancement, it has maintained sustained prosperity and development. In this paper, the inte... The telecommunications industry has been undergoing tremendous technological changes, and owning to continuous technological advancement, it has maintained sustained prosperity and development. In this paper, the interplay between technology, market and government in telecommunications is discussed briefly, and then we introduce technology and government into the traditional SCP(Structure – Conduct – Performance) paradigm to develop an industry analysis framework called TGM(SCP)(Technology – Government – Market(Structure – Conduct – Performance)). Based on this framework, we present the spiral coevolution model which elaborates on the interaction mechanism of technological innovation with government regulation and market dynamics from the perspective of industry evolution. Our study indicates that the development of the telecommunications industry is the result of the coevolution of technology, government regulation and market forces, and among the three actors, technology is the fundamental driving force. Relative to the "invisible hand"(market) and "visible hand"(government), we conceptualize technology as the "third hand", which fundamentally drives the development of telecommunications industry in coordination with the other two hands. We also provide several policy implications regarding these findings. 展开更多
关键词 technological innovation government regulation telecommunications evolutionary theory
在线阅读 下载PDF
Telecommunications reforms in Pakistan-lessons and suggestions for China
2
作者 Muhammad Khalil Shahid Tang Shou-lian 《China Communications》 SCIE CSCD 2007年第2期106-114,共9页
The worldwide strategy for the development of telecommunications has been the opening of the telecom sector to competition and private investment.This paper focuses on telecommunications reforms and its outcomes in Pa... The worldwide strategy for the development of telecommunications has been the opening of the telecom sector to competition and private investment.This paper focuses on telecommunications reforms and its outcomes in Pakistan and discusses some lessons and suggestions for China who is still in the process of formulating telecom law.After liberalization and deregulation,telecom industry in Pakistan is tremendously growing and is in a transition phase from the monopoly to the competition.Government policies and independent regulator is playing critical role in this growth.This paper suggests that speed up formulation of Telecom Law,establishment of independent regulatory and antitrust agencies are need of time for the China telecom industry.Further,China will have to give special attention to accommodate convergence in its coming model of telecommunications reforms. 展开更多
关键词 Pakistan China REFORMS telecommunications REGULATIONS COMPETITION
在线阅读 下载PDF
National Network Operation Center for Ethiopian Telecommunications Corporation
3
作者 Tewodros Hailemeskel 《ZTE Communications》 2008年第2期48-50,共3页
Ethiopian Telecommunications Corporation (ETC) has acquired a patchwork of systems and processes that makes it difficult to cost-efficiently troubleshoot network faults, launch new services quickly, and track and tune... Ethiopian Telecommunications Corporation (ETC) has acquired a patchwork of systems and processes that makes it difficult to cost-efficiently troubleshoot network faults, launch new services quickly, and track and tune the performance of services once delivered. This patchwork also results in increased operational and capital expenditures, so there is an obvious need for ETC to improve and evolve the network and service management environment. Evolving ETC’s network and service management systems and processes shall be done in a well organized phased approach. ZTE is the first choice for ETC to assume this challenging responsibility and provide the National Network Operation Center (NNOC) solution. 展开更多
关键词 ETC OSS ZTE NGN
在线阅读 下载PDF
Identifying Fake and Potential Corporate Members in Telecommunications Operators
4
作者 石文华 张晓航 +1 位作者 龚雪 吕廷杰 《China Communications》 SCIE CSCD 2013年第8期150-157,共8页
Nowadays,mobile operators in China mainland are facing fierce competition from one to another,and their focus of customer competition has,in general,shifted from public to corporate customers.One big challenge in corp... Nowadays,mobile operators in China mainland are facing fierce competition from one to another,and their focus of customer competition has,in general,shifted from public to corporate customers.One big challenge in corporate customer management is how to identify fake corporate members and potential corporate members from corporate customers.In this study,we have proposed an identification method that combines the rule-based and probabilistic methods.Through this method,fake corporate members can be eliminated and external potential members can be mined.The experimental results based on the data obtained from a local mobile operator revealed that the proposed method can effectively and efficiently identify fake and potential corporate members.The proposed method can be used to improve the management of corporate customers. 展开更多
关键词 fake-member identification corporate customer rule-based method kernel density estimation
在线阅读 下载PDF
BNetzA (Federal Network Agency for Electricity, Gas, Telecommunications, Post and Railway)1 and Its Role in Energy Infrastructure Regulation and Planning/Permitting
5
作者 Annegret Groebel 《Journal of Energy and Power Engineering》 2018年第10期477-505,共29页
The following contribution aims at explaining BNetzA’s role in energy infrastructure regulation and planning/permitting of high-voltage electricity nationwide and cross-border transmission lines. It shows the interpl... The following contribution aims at explaining BNetzA’s role in energy infrastructure regulation and planning/permitting of high-voltage electricity nationwide and cross-border transmission lines. It shows the interplay of the two main regulatory instruments and the planning/permitting task as well as more generally the changing role of the regulator in the era of energy transition. The article is based on two presentations on the topic, one at the VIIth WFER in Mexico in March 2018 and one at a conference on “The Governance of Maintenance and Investment in Infrastructures” of the University of Paris-Dauphine in April 2018. 展开更多
关键词 ENERGY REGULATION “Energiewende” ENERGY infrastructure incentive REGULATION rate of return on EQUITY grid expansion planning/permitting TENDERING of RENEWABLES
在线阅读 下载PDF
Design of high-speed MUTC-PD with electric field regulation layer 被引量:1
6
作者 XU Jian-bo LIU Kai +4 位作者 DONG Xiao-wen DUAN Xiao-feng HUANG Yong-qing WANG Qi REN Xiao-min 《中国光学(中英文)》 北大核心 2025年第2期393-400,共8页
This paper proposes a novel modified uni-traveling-carrier photodiode(MUTC-PD)featuring an electric field regulation layer:a p-type doped thin layer inserted behind the PD’s n-doped cliff layer.This electric field re... This paper proposes a novel modified uni-traveling-carrier photodiode(MUTC-PD)featuring an electric field regulation layer:a p-type doped thin layer inserted behind the PD’s n-doped cliff layer.This electric field regulation layer enhances the PD’s performance by not only reducing and smoothing the electric field intensity in the collector layer,allowing photo-generated electrons to transit at peak drift velocity,but also improving the electric field intensity in the depleted absorber layer and optimizing the photo-generated carriers’saturated transit performance.Additionally,the transport characteristics of the peak drift velocity of photogenerated electrons in the device’s collection layer can be used to optimize its parasitic characteristics.The electron’s peak drift velocity compensates for the lost transit time.Thus improving the 3 dB bandwidth of the PD’s photo response.Finally obtains a MUTC-PD with a 3 dB bandwidth of 68 GHz at a responsivity of 0.502 A/W,making it suitable for 100 Gbit/s optical receivers. 展开更多
关键词 peak electron drift velocity transit performance MUTC-PD optical fiber communication optical interconnect
在线阅读 下载PDF
Recent progress on artificial intelligence-enhanced multimodal sensors integrated devices and systems 被引量:2
7
作者 Haihua Wang Mingjian Zhou +5 位作者 Xiaolong Jia Hualong Wei Zhenjie Hu Wei Li Qiumeng Chen Lei Wang 《Journal of Semiconductors》 2025年第1期179-192,共14页
Multimodal sensor fusion can make full use of the advantages of various sensors,make up for the shortcomings of a single sensor,achieve information verification or information security through information redundancy,a... Multimodal sensor fusion can make full use of the advantages of various sensors,make up for the shortcomings of a single sensor,achieve information verification or information security through information redundancy,and improve the reliability and safety of the system.Artificial intelligence(AI),referring to the simulation of human intelligence in machines that are programmed to think and learn like humans,represents a pivotal frontier in modern scientific research.With the continuous development and promotion of AI technology in Sensor 4.0 age,multimodal sensor fusion is becoming more and more intelligent and automated,and is expected to go further in the future.With this context,this review article takes a comprehensive look at the recent progress on AI-enhanced multimodal sensors and their integrated devices and systems.Based on the concept and principle of sensor technologies and AI algorithms,the theoretical underpinnings,technological breakthroughs,and pragmatic applications of AI-enhanced multimodal sensors in various fields such as robotics,healthcare,and environmental monitoring are highlighted.Through a comparative study of the dual/tri-modal sensors with and without using AI technologies(especially machine learning and deep learning),AI-enhanced multimodal sensors highlight the potential of AI to improve sensor performance,data processing,and decision-making capabilities.Furthermore,the review analyzes the challenges and opportunities afforded by AI-enhanced multimodal sensors,and offers a prospective outlook on the forthcoming advancements. 展开更多
关键词 SENSOR multimodal sensors machine learning deep learning intelligent system
在线阅读 下载PDF
All-optical nonlinear activation functions realized on phasechange photonic integrated circuits with microheaters 被引量:2
8
作者 Jiyuan Jiang Bingxin Ding +8 位作者 Shiyu Li Xin Zhang Haihua Wang Jie Wu Xiaoyan Liu Zhou Wang Xiaojuan Lian Wen Huang Lei Wang 《Journal of Semiconductors》 2025年第2期122-131,共10页
Photonic neural networks have garnered significant attention in recent years due to their ultra-high computational speed,broad bandwidth,and parallel processing capabilities.However,compared to conventional electronic... Photonic neural networks have garnered significant attention in recent years due to their ultra-high computational speed,broad bandwidth,and parallel processing capabilities.However,compared to conventional electronic nonlinear activa-tion function(NAF),progress on efficient and easily implementable optical nonlinear activation function(ONAF)was barely reported.To address this issue,we proposed a programmable,low-loss ONAF device based on a silicon micro-ring resonator capped with the Antimony selenide(Sb_(2)Se_(3))thin films,and with indium tin oxide(ITO)used as the microheater.Leveraging our self-developed phase-transformation kinetic and optical models,we successfully simulated the phase-transition behavior of Sb_(2)Se_(3)and three different ONAFs—ELU,ReLU,and radial basis function(RBF)were achieved according to discernible optical responses of proposed devices under different phase-change extents.Classification results from the Fashion MNIST dataset demonstrated that these ONAFs can be considered as appropriate substitutes for traditional NAF.This indicated the bright prospect of the proposed device for nonlinear activation function in future photonic neural networks. 展开更多
关键词 ONAF Sb_(2)Se_(3) MICROHEATER photonic neural networks
在线阅读 下载PDF
Does wetland degradation impact bird diversity differently across seasons?A case study of Zoige Alpine Wetland ecosystem 被引量:1
9
作者 Chen Yang Siheng Chen Tianpei Guan 《Avian Research》 2025年第1期21-29,共9页
Wetland degradation is an escalating global challenge with profound impacts on animal diversity,particularly during successional processes.Birds,as highly mobile and environmentally sensitive organisms,serve as effect... Wetland degradation is an escalating global challenge with profound impacts on animal diversity,particularly during successional processes.Birds,as highly mobile and environmentally sensitive organisms,serve as effective indicators of ecological change.While previous studies have primarily focused on local community structures and species diversity during a specific season,there is a need to extend the research timeframe and explore broader spatial variations.Additionally,expanding from simple species diversity indices to more multidimensional diversity indices would provide a more comprehensive understanding of wetland health and resilience.To address these gaps,we investigated the effects of wetland degradation on bird diversity across taxonomic,phylogenetic,and functional dimensions in the Zoige Wetland,a plateau meadow wetland biodiversity hotspot.Surveys were conducted during both breeding(summer)and overwintering(winter)seasons across 20 transects in 5 sampling areas,representing 4 degradation levels(pristine,low,medium,and high).Our study recorded a total of 106 bird species from 32 families and 14 orders,revealing distinct seasonal patterns in bird community composition and diversity.Biodiversity indices were significantly higher in pristine and low-degraded wetlands,particularly benefiting waterfowl(Anseriformes,Ciconiiformes)and wading birds(Charadriiformes)in winter,when these areas provided superior food resources and habitat conditions.In contrast,medium and highly degraded wetlands supported increased numbers of terrestrial birds(Passeriformes)and raptors(Accipitriformes,Falconiformes).Seasonal differences in taxonomic,phylogenetic,and functional diversity indices highlighted the contrasting ecological roles of wetlands during breeding and overwintering periods.Furthermore,indicator species analysis revealed key species associated with specific degradation levels and seasons,providing valuable insights into wetland health.This study underscores the importance of spatiotemporal dynamics in understanding avian responses to wetland degradation.By linking seasonal patterns of bird diversity to habitat conditions,our findings contribute to conservation efforts and provide a framework for assessing wetland degradation and its ecological impacts. 展开更多
关键词 Bird diversity Community similarity Degraded wetland Indicator species Season effect
在线阅读 下载PDF
Sympathetic Solar Eruption on 2024 February 9 被引量:1
10
作者 Shu-Yue Li Qing-Min Zhang +4 位作者 Bei-Li Ying Li Feng Ying-Na Su Mu-Sheng Lin Yan-Jie Zhang 《Research in Astronomy and Astrophysics》 2025年第1期182-191,共10页
In this paper,we perform a follow-up investigation of the solar eruption originating from active region 13575 on 2024 February 9.The primary eruption of a hot channel generates an X3.4 class flare,a full-halo coronal ... In this paper,we perform a follow-up investigation of the solar eruption originating from active region 13575 on 2024 February 9.The primary eruption of a hot channel generates an X3.4 class flare,a full-halo coronal mass ejection(CME),and an extreme-ultraviolet(EUV)wave.Interaction between the wave and a quiescent prominence(QP)leads to a large-amplitude,transverse oscillation of QP.After the transverse oscillation,QP loses equilibrium and rises up.The ascending motion of the prominence is coherently detected and tracked up to∼1.68 R_(⊙)by the Solar UltraViolet Imager onboard the GOES-16 spacecraft and up to∼2.2 R_(⊙)by the Solar Corona Imager(SCI_UV)of the LyαSolar Telescope onboard the ASO-S spacecraft.The velocity increases linearly from 12.3 to 68.5 km s^(−1)at 18:30 UT.The sympathetic eruption of QP drives the second CME with a typical three-part structure.The bright core comes from the eruptive prominence,which could be further observed up to∼3.3 R_(⊙) by the Large Angle Spectroscopic Coronagraph onboard the Solar and Heliospheric Observatory mission.The leading edge of the second CME accelerates continuously from∼120 to∼277 km s^(−1).The EUV wave plays an important role in linking the primary eruption with the sympathetic eruption. 展开更多
关键词 SUN flares-Sun filaments prominences-Sun coronal mass ejections(CMEs)
在线阅读 下载PDF
Highly responsive photodetectors based on NiPS_(3)/WS_(2)van der Waals type-Ⅱheterostructures 被引量:1
11
作者 Zhiteng Li Yian Wang +4 位作者 Zhenming Qiu Lin Wang Xiaofeng Liu Zhengwei Chen Xiao Zhang 《Chinese Physics B》 2025年第2期394-399,共6页
A heterostructure photodetector composed of few-layer NiPS_(3)/WS_(2)is made by using mechanical exfoliation and micro-nano fabrication techniques.The photodetector exhibits a broad-band response wavelengths of rangin... A heterostructure photodetector composed of few-layer NiPS_(3)/WS_(2)is made by using mechanical exfoliation and micro-nano fabrication techniques.The photodetector exhibits a broad-band response wavelengths of ranging of 405 nm and 800 nm.Under the light illumination of 405-nm wavelength and a bias voltage of-2V,the photoresponsivity is 62.6 m A/W and the specific detectivity is 8.59×10^(10)Jones.In addition,the device demonstrates a relatively fast response with rise and fall times of 70 ms and 120 ms.Theoretical calculation suggest that this excellent performance can be ascribed to the type-Ⅱband alignment at the NiPS_3/WS_2 heterostructure interface. 展开更多
关键词 HETEROJUNCTION PHOTODETECTOR NiPS_(3) WS_(2)
原文传递
Integrated Optical True Time Delay Phased Array Antenna Systems 被引量:1
12
作者 Qi Zihang Yang Linhui +1 位作者 Zhao Wenyu Li Xiuping 《China Communications》 2025年第5期152-172,共21页
The integrated optical true time delay phased array antenna system has the advantages of high bandwidth,small size,low loss and strong antiinterference capability,etc.The high integration of the optically controlled p... The integrated optical true time delay phased array antenna system has the advantages of high bandwidth,small size,low loss and strong antiinterference capability,etc.The high integration of the optically controlled phased array antenna system is a necessary trend for the future development of the phased array,and it is also a major focus and difficulty in the current research of integrated microwave photonics.This paper firstly introduces the basic principle and development history of optical true time delay phased array antenna system based on microwave photonics,and briefly introduces the main implementation methods and integration platform of optical true time delay.Then,the application and development prospect of optical true time delay technology in beam control of phased array antenna system are mainly presented.Finally,according to the current research progress,the possible research directions of integrated optically controlled phased array antenna systems in the future are proposed. 展开更多
关键词 microwave photonics optical switch optical true time delay phased array antenna siliconbased integration
在线阅读 下载PDF
The Impact of Chinese Teachers’ Career Calling on Job Burnout: A Dual Path Model of Career Adaptability and Work Engagement 被引量:1
13
作者 Huaruo Chen Wanru Song +3 位作者 Jian Xie Huadi Wang Feifei Zheng Ya Wen 《International Journal of Mental Health Promotion》 2025年第3期379-400,共22页
Objectives:Teachers are facing unprecedented new challenges leading them to face an increasing number of tasks that are not part of their job,as well as having to cope with the additional skills acquisition that comes... Objectives:Teachers are facing unprecedented new challenges leading them to face an increasing number of tasks that are not part of their job,as well as having to cope with the additional skills acquisition that comes with non-traditional forms of teaching and learning,and increased work pressure leading to an increase in the rate of teachers leaving the profession.Therefore,this study aims to explore the mechanism of the career calling on job burnout through career adaptability and work engagement.Methods:This study conducted a cross-sectional survey of 465 primary and secondary school teachers(PSST)in China's Mainland from the perspective of work adjustment and used structural equation modeling(SEM)to examine the mediating roles of career adaptability and work engagement in the relationship between teachers’career calling and job burnout.Results:The results show that PSSTs are above average in career calling,career adaptability,and work engagement,while job burnout is below average.A significant positive or negative correlation exists between career calling,career adaptability,work engagement,and job burnout.The result of path analysis indicates that career adaptability and work engagement exert an indirect influence on the job burnout of PSST through three paths:namely,the independent intermediary role of career adaptability(EV=−0.144),the independent intermediary role of work engagement(EV=0.172)and the chain intermediary role of the two(EV=0.176).Conclusion:This study emphasizes the importance of career adaptability and work engagement in teacher development in regulating career calling and job burnout.Therefore,on the one hand,we think that if managers want to reduce teachers’job burnout,they need to pay more attention to teachers’career adaptability and work engagement,rather than relying solely on teachers’career calling.On the other hand,it is to remind teachers not to rely on their adjustment to adapt to the work,but also to need outside help as much as possible. 展开更多
关键词 Career calling job burnout career adaptability work engagement structural equation model(SEM)
在线阅读 下载PDF
Bioinspired Passive Tactile Sensors Enabled by Reversible Polarization of Conjugated Polymers
14
作者 Feng He Sitong Chen +3 位作者 Ruili Zhou Hanyu Diao Yangyang Han Xiaodong Wu 《Nano-Micro Letters》 SCIE EI CAS 2025年第1期361-377,共17页
Tactile perception plays a vital role for the human body and is also highly desired for smart prosthesis and advanced robots.Compared to active sensing devices,passive piezoelectric and triboelectric tactile sensors c... Tactile perception plays a vital role for the human body and is also highly desired for smart prosthesis and advanced robots.Compared to active sensing devices,passive piezoelectric and triboelectric tactile sensors consume less power,but lack the capability to resolve static stimuli.Here,we address this issue by utilizing the unique polarization chemistry of conjugated polymers for the first time and propose a new type of bioinspired,passive,and bio-friendly tactile sensors for resolving both static and dynamic stimuli.Specifically,to emulate the polarization process of natural sensory cells,conjugated polymers(including poly(3,4-ethylenedioxythiophen e):poly(styrenesulfonate),polyaniline,or polypyrrole)are controllably polarized into two opposite states to create artificial potential differences.The controllable and reversible polarization process of the conjugated polymers is fully in situ characterized.Then,a micro-structured ionic electrolyte is employed to imitate the natural ion channels and to encode external touch stimulations into the variation in potential difference outputs.Compared with the currently existing tactile sensing devices,the developed tactile sensors feature distinct characteristics including fully organic composition,high sensitivity(up to 773 mV N^(−1)),ultralow power consumption(nW),as well as superior bio-friendliness.As demonstrations,both single point tactile perception(surface texture perception and material property perception)and two-dimensional tactile recognitions(shape or profile perception)with high accuracy are successfully realized using self-defined machine learning algorithms.This tactile sensing concept innovation based on the polarization chemistry of conjugated polymers opens up a new path to create robotic tactile sensors and prosthetic electronic skins. 展开更多
关键词 Passive tactile sensors Reversible polarization of conjugated polymers Tactile perception Machine learning algorithm Object recognition
在线阅读 下载PDF
Light-responsive nanomaterials for biofilm removal in root canal treatment 被引量:1
15
作者 Di An Mingdong She +5 位作者 Ziyang Zhang Ting Zhang Miaomiao Xu Jinjun Shao Qian Shen Xuna Tang 《Chinese Chemical Letters》 2025年第2期10-20,共11页
Various chemical irrigants and drugs have been employed for intra-canal disinfection in root canal therapy(RCT).However,due to the complexity of root canal anatomy,many drugs still exhibit poor penetrability and antib... Various chemical irrigants and drugs have been employed for intra-canal disinfection in root canal therapy(RCT).However,due to the complexity of root canal anatomy,many drugs still exhibit poor penetrability and antibiotic resistance,leading to suboptimal treatment outcomes.Thus,it is challenging to remove the organic biofilms from root canals.In recent years,light-responsive therapy,with deeper tissue penetration than traditional treatments,has emerged as an effective RCT modality.Herein,this review summarizes the recent development of light-responsive nanomaterials for biofilm removal in RCT.The light-responsive nanomaterials and the corresponding therapeutic methods in RCT,including photodynamic therapy(PDT),photothermal therapy(PTT),and laser-activated therapy,are highlighted.Finally,the challenges that light-responsive nanomaterials and treatment modalities will encounter to conquer the biofilm in future RCT are discussed.This review is believed to significantly accelerate the future development of light-responsive nanomaterials for RCT from bench to bedside. 展开更多
关键词 Light-responsive nanomaterials BIOFILM Root canal treatment Photodynamic therapy Photothermal therapy
原文传递
Enhanced battery life prediction with reduced data demand via semi-supervised representation learning 被引量:1
16
作者 Liang Ma Jinpeng Tian +2 位作者 Tieling Zhang Qinghua Guo Chi Yung Chung 《Journal of Energy Chemistry》 2025年第2期524-534,I0011,共12页
Accurate prediction of the remaining useful life(RUL)is crucial for the design and management of lithium-ion batteries.Although various machine learning models offer promising predictions,one critical but often overlo... Accurate prediction of the remaining useful life(RUL)is crucial for the design and management of lithium-ion batteries.Although various machine learning models offer promising predictions,one critical but often overlooked challenge is their demand for considerable run-to-failure data for training.Collection of such training data leads to prohibitive testing efforts as the run-to-failure tests can last for years.Here,we propose a semi-supervised representation learning method to enhance prediction accuracy by learning from data without RUL labels.Our approach builds on a sophisticated deep neural network that comprises an encoder and three decoder heads to extract time-dependent representation features from short-term battery operating data regardless of the existence of RUL labels.The approach is validated using three datasets collected from 34 batteries operating under various conditions,encompassing over 19,900 charge and discharge cycles.Our method achieves a root mean squared error(RMSE)within 25 cycles,even when only 1/50 of the training dataset is labelled,representing a reduction of 48%compared to the conventional approach.We also demonstrate the method's robustness with varying numbers of labelled data and different weights assigned to the three decoder heads.The projection of extracted features in low space reveals that our method effectively learns degradation features from unlabelled data.Our approach highlights the promise of utilising semi-supervised learning to reduce the data demand for reliability monitoring of energy devices. 展开更多
关键词 Lithium-ion batteries Battery degradation Remaining useful life Semi-supervised learning
在线阅读 下载PDF
Compactness of Fractional Calderón Type Commutators on Morrey Spaces
17
作者 LI Aobo MEI Ting WEI Qi 《数学进展》 北大核心 2025年第4期858-870,共13页
In this paper,the authors study the fractional Calderon type commutator T_(Ω,α)^(A)and its maximal operator M_(Ω,α)^(A)with kernels having some kinds of Log-type Dini-condition and obtain the compactness on Morrey... In this paper,the authors study the fractional Calderon type commutator T_(Ω,α)^(A)and its maximal operator M_(Ω,α)^(A)with kernels having some kinds of Log-type Dini-condition and obtain the compactness on Morrey spaces L^(p,λ)(R^(n)). 展开更多
关键词 Calderón type commutator COMPACTNESS Log-type Dini-condition Morrey space
原文传递
WGM Lasing from Toroid-shaped ZnO Microdisk Pivoted on Si
18
作者 ZHU Gangyi YAN Xinyue +6 位作者 YE Peng QIN Feifei WANG Zixuan LI Binghui LU Junfeng WANG Xiaoxuan XU Chunxiang 《发光学报》 北大核心 2025年第1期12-22,共11页
Although it has a significant advantage in gain properties,the lack of selective etching processes hinders ZnO lasing in on-chip applications.Herein,the circular ZnO microdisk pivoted on Si substrate is fabricated thr... Although it has a significant advantage in gain properties,the lack of selective etching processes hinders ZnO lasing in on-chip applications.Herein,the circular ZnO microdisk pivoted on Si substrate is fabricated through depositing ZnO on patterned silicon on an insulator(SOI)substrate.The cavity structure,morphology,and photoluminescence(PL)properties are studied systematically.The cavity shows a well-defined circular structure with oxygen vacancies.Under the synergistic action of surface tension and stress,the ZnO microdisk shows a unique toroid structure with a high sidewall surface finish.The ZnO microcavity(8μm in diameter)shows optically pumped whispering gallery modes(WGMs)lasing in the ultraviolet region with a Q factor exceeding 1300.More interestingly,the quality of the toroid ZnO microdisk cavity is high enough to support the bandgap renormalization(BGR)phenomenon.With the increasing pumping power,the lasing spectra will be modulated.The lasing spectrum undergoes a Burstein-Moss(BM)effect-induced blueshift and an electron-hole plasma(EHP)effect-induced redshift. 展开更多
关键词 ZNO MICRODISK tunable lasing molecular beam epitaxy
在线阅读 下载PDF
Optimal Investment Strategy for an Insurer in Two Currency Markets
19
作者 ZHOU Qianqian 《应用概率统计》 北大核心 2025年第1期1-16,共16页
In this paper,we study the optimal investment problem of an insurer whose surplus process follows the diffusion approximation of the classical Cramer-Lundberg model.Investment in the foreign markets is allowed,and the... In this paper,we study the optimal investment problem of an insurer whose surplus process follows the diffusion approximation of the classical Cramer-Lundberg model.Investment in the foreign markets is allowed,and therefore,the foreign exchange rate model is incorporated.Under the allowing of selling and borrowing,the problem of maximizing the expected exponential utility of terminal wealth is studied.By solving the corresponding Hamilton-Jacobi-Bellman equations,the optimal investment strategies and value functions are obtained.Finally,numerical analysis is presented. 展开更多
关键词 Cramer-Lundberg model exponential utility Hamilton-Jacobi-Bellman equation optimal investment strategy foreign exchange rate
在线阅读 下载PDF
Contribution of Transmembrane Protein 68 to Triglyceride Synthesis and Lipid Droplet Formation Differs From Diacylglycerol Acyltransferase
20
作者 YU Qing FU Yang-Yang +3 位作者 ZENG Fan-Si PANG Hui-Min HUANG Fei-Fei CHANG Ping-An 《生物化学与生物物理进展》 北大核心 2025年第3期705-715,共11页
Objective To characterize transmembrane protein 68(TMEM68)in an alternative triacylglycerol(TAG)biosynthesis pathway,and determine the interplay between TMEM68 and the canonical TAG synthesis enzyme acyl-CoA:diacylgly... Objective To characterize transmembrane protein 68(TMEM68)in an alternative triacylglycerol(TAG)biosynthesis pathway,and determine the interplay between TMEM68 and the canonical TAG synthesis enzyme acyl-CoA:diacylglycerol acyltransferase(DGAT).Methods Effects of exogenous fatty acid and monoacylglycerol on TAG synthesis and lipid droplet(LD)formation in TMEM68 overexpression and knockout cells treated with DGAT inhibitor or not were investigated by comparing LD morphology,Oil Red O staining,and measurement of TAG levels.LDs were stained with fluorescence dye and observed by confocal fluorescence microscopy.TAG levels were determined with an enzyme-based triglyceride assay kit.Colocalization of TMEM68 and DGAT1 was detected by co-expression and confocal fluorescence microscopy and their interaction was determined by co-immunoprecipitation.RT-qPCR and immunoblotting assay were used to detect the expression of DGAT1.Results The synthesis of TAG catalyzed by TMEM68 was independent of DGAT activity.Surplus exogenous fatty acids and monoacylglycerol promoted TAG synthesis mainly through DGAT in human neuroblastoma cells.The LDs formed by TMEM68 were different in morphology from those by DGAT.In addition,TMEM68 and DGAT1 colocalized in the same endoplasmic reticulum(ER)compartment but did not interact physically.TMEM68 overexpression reduced the expression of DGAT1,the major DGAT enzyme involved in TAG synthesis,while TMEM68 knockout had little impact.Conclusion The TMEM68-mediated TAG synthesis pathway has distinct features from the canonical DGAT pathway,however,TMEM68 and DGAT may coregulate intracellular TAG levels. 展开更多
关键词 TRIACYLGLYCEROL lipid droplet TMEM68 GAT
原文传递
上一页 1 2 250 下一页 到第
使用帮助 返回顶部