The uncertainty principle is a fundamental principle of quantum mechanics, but its exact mathematical expression cannot obtain correct results when used to solve theoretical problems such as the energy levels of hydro...The uncertainty principle is a fundamental principle of quantum mechanics, but its exact mathematical expression cannot obtain correct results when used to solve theoretical problems such as the energy levels of hydrogen atoms, one-dimensional deep potential wells, one-dimensional harmonic oscillators, and double-slit experiments. Even after approximate treatment, the results obtained are not completely consistent with those obtained by solving Schrödinger’s equation. This indicates that further research on the uncertainty principle is necessary. Therefore, using the de Broglie matter wave hypothesis, we quantize the action of an elementary particle in natural coordinates and obtain the quantization condition and a new deterministic relation. Using this quantization condition, we obtain the energy level formulas of an elementary particle in different conditions in a classical way that is completely consistent with the results obtained by solving Schrödinger’s equation. A new physical interpretation is given for the particle eigenfunction independence of probability for an elementary particle: an elementary particle is in a particle state at the space-time point where the action is quantized, and in a wave state in the rest of the space-time region. The space-time points of particle nature and the wave regions of particle motion constitute the continuous trajectory of particle motion. When an elementary particle is in a particle state, it is localized, whereas in the wave state region, it is nonlocalized.展开更多
Improvements in early screening,new diagnostic techniques,and surgical treatment have led to continuous downward trends in hepatocellular carcinoma(HCC)morbidity and mortality rates.However,high recurrence and refract...Improvements in early screening,new diagnostic techniques,and surgical treatment have led to continuous downward trends in hepatocellular carcinoma(HCC)morbidity and mortality rates.However,high recurrence and refractory cancer after hepatectomy remain important factors affecting the long-term prognosis of HCC.The clinical characteristics and prognosis of recurrent HCC are heterogeneous,and guidelines on treatment strategies for recurrent HCC are lacking.Therapies such as surgical resection,radiofrequency ablation,and transhepatic arterial chemoembolization are effective for tumors confined to the liver,and targeted therapy is a very important treatment for unresectable recurrent HCC with systemic metastasis.With the deepening of the understanding of the immune microenvironment of HCC,blocking immune checkpoints to enhance the antitumor immune response has become a new direction for the treatment of HCC.In addition,improvements in the tumor immune microenvironment caused by local treatment may provide an opportunity to improve the therapeutic effect of HCC treatment.Ongoing and future clinical trial data of combined therapy may develop the new treatment scheme for recurrent HCC.This paper reviews the pattern of recurrent HCC and the characteristics of the immune microenvironment,demonstrates the basis for combining local treatment and systemic treatment,and reports current evidence to better understand current progress and future approaches in the treatment of recurrent HCC.展开更多
Sensor localization is crucial for the configuration and applications of wireless sensor network (WSN). A novel distributed localization algorithm, MDS-DC was proposed for wireless sensor network based on multidimensi...Sensor localization is crucial for the configuration and applications of wireless sensor network (WSN). A novel distributed localization algorithm, MDS-DC was proposed for wireless sensor network based on multidimensional scaling (MDS) and the shortest path distance correction. In MDS-DC, several local positioning regions with reasonable distribution were firstly constructed by an adaptive search algorithm, which ensures the mergence between the local relative maps of the adjacent local position regions and can reduce the number of common nodes in the network. Then, based on the relationships between the estimated distances and actual distances of anchors, the distance estimation vectors of sensors around anchors were corrected in each local positioning region. During the computations of the local relative coordinates, an iterative process, which is the combination of classical MDS algorithm and SMACOF algorithm, was applied. Finally, the global relative positions or absolute positions of sensors were obtained through merging the relative maps of all local positioning regions. Simulation results show that MDS-DC has better performances in positioning precision, energy efficiency and robustness to range error, which can meet the requirements of applications for sensor localization in WSN.展开更多
Computational e ciency and accuracy always conflict with each other in molecular dynamics(MD) simulations. How to enhance the computational e ciency and keep accuracy at the same time is concerned by each correspondin...Computational e ciency and accuracy always conflict with each other in molecular dynamics(MD) simulations. How to enhance the computational e ciency and keep accuracy at the same time is concerned by each corresponding researcher. However, most of the current studies focus on MD algorithms, and if the scale of MD model could be reduced, the algorithms would be more meaningful. A local region molecular dynamics(LRMD) simulation method which can meet these two factors concurrently in nanoscale sliding contacts is developed in this paper. Full MD simulation is used to simulate indentation process before sliding. A criterion called contribution of displacement is presented, which is used to determine the e ective local region in the MD model after indentation. By using the local region, nanoscale sliding contact between a rigid cylindrical tip and an elastic substrate is investigated. Two two?dimensional MD models are presented, and the friction forces from LRMD simulations agree well with that from full MD simulations, which testifies the e ectiveness of the LRMD simulation method for two?dimensional cases. A three?dimensional MD model for sliding contacts is developed then to show the validity of the LRMD simulation method further. Finally, a discussion is carried out by the principles of tribology. In the discussion, two two?dimensional full MD models are used to simulate the nanoscale sliding contact problems. The results indicate that original smaller model will induce higher equivalent scratching depth, and then results in higher friction forces, which will help to explain the mechanism how the LRMD simulation method works. This method can be used to reduce the scale of MD model in large scale simulations, and it will enhance the computational e ciency without losing accuracy during the simula?tion of nanoscale sliding contacts.展开更多
This paper attempts to study regional differentiation of cuisine in China and set up a rudimentary framework for regional characteristic of cuisine This framework is mainly concerned with regional school of cuisine (o...This paper attempts to study regional differentiation of cuisine in China and set up a rudimentary framework for regional characteristic of cuisine This framework is mainly concerned with regional school of cuisine (or cuisine systems) and regional dishes It also gives them some explanations of the process of the formation展开更多
The cooperative movement has played a very important role in the social and economic development of all countries since 19th eentury's second half. Cooperatives provide health, housing, and banking services; they pro...The cooperative movement has played a very important role in the social and economic development of all countries since 19th eentury's second half. Cooperatives provide health, housing, and banking services; they promote education and gender equality; they protect the environment and workers' rights. According to 2014's data, the total number of cooperatives is 79,486 in Turkey, while the total number of partners of cooperatives is approximately 7.8 million. The research's sample group "Hidirlik Agricultural Development Cooperative" was founded by the wife of the Seferihisar's mayor and six women. It has been a subject of curiousity that the contributions of the cooperative have developed the economy of the region since 2010. Therefore, various questions asked to the president and members of the cooperative, and significant results were obtained. In this research "Interview technique" was used. The fact that within the boundaries of local governments, the establishment of "women's cooperatives" and their active management can be supported with 10 basic criteria for the regional and national development can be predicted. These dimensions: ecological balance and sensitivity, the revival of the tourism sector, the mobility of logistics activities, new investments and increase of land value, the increase of women employment, the increase of healthy living standards, increase of competitiveness and trade earnings, the creation of new brands, widespread of the agricultural sector, and the increase of social and educational level of women. The similiar implementation of "Seferihisar Women's Cooperatives Model" in the research is considered form an important enterprenurship model not only in Turkey but also for all countries.展开更多
Nowadays, the disparity of the basic pension in local regions of China can be described as follows: the low level of the unification of the basic pension systems, the large disparity of the level of the basic pension,...Nowadays, the disparity of the basic pension in local regions of China can be described as follows: the low level of the unification of the basic pension systems, the large disparity of the level of the basic pension, and unfairness of the enterprises’ payment for the basic pension in different local regions in China. These have already brought many negative influences, which have greatly held back the development of the society and national economy. We should build the basic pension system in all local regions of China as a whole, which can cover all people and decrease the disparity in different local regions in China.展开更多
To reduce the computation cost of a combined probabilistic graphical model and a deep neural network in semantic segmentation, the local region condition random field (LRCRF) model is investigated which selectively ap...To reduce the computation cost of a combined probabilistic graphical model and a deep neural network in semantic segmentation, the local region condition random field (LRCRF) model is investigated which selectively applies the condition random field (CRF) to the most active region in the image. The full convolutional network structure is optimized with the ResNet-18 structure and dilated convolution to expand the receptive field. The tracking networks are also improved based on SiameseFC by considering the frame relations in consecutive-frame traffic scene maps. Moreover, the segmentation results of the greyscale input data sets are more stable and effective than using the RGB images for deep neural network feature extraction. The experimental results show that the proposed method takes advantage of the image features directly and achieves good real-time performance and high segmentation accuracy.展开更多
In China, 10 ethnic minorities with a combined population of over 20 million people are followers of Islam. In Ningxia Hui Autonomous Region, the population is nearly 6 million, a-mong which the Islamic population is ...In China, 10 ethnic minorities with a combined population of over 20 million people are followers of Islam. In Ningxia Hui Autonomous Region, the population is nearly 6 million, a-mong which the Islamic population is about 2 million. In China as a whole, more than 20 million people enjoy eating food prepared according to Islamic guidelines, known as hal'al food.展开更多
Recently in 2020, in southern Saudi Arabia three felt earthquakes occurred in Asir region, in the Khamis Mushait, Ahad Rafidah, and AL-Shuqiq area, of magnitude 3.45, 3.1, and 3.5, respectively. The most interesting e...Recently in 2020, in southern Saudi Arabia three felt earthquakes occurred in Asir region, in the Khamis Mushait, Ahad Rafidah, and AL-Shuqiq area, of magnitude 3.45, 3.1, and 3.5, respectively. The most interesting event was the earthquake that occurred in Khamis Mushait area, along a lake formed behind the Tadhah Dam (~7 km), fearing any damage to the dam’s body and the consequent destruction. Moment tensors for each event were computed for determining fault plane solutions, seismic moment, moment magnitude (Mw) and the CLVD ratio. In addition, the frequency contents in the waveforms of each event were identified. The obtained focal mechanisms represent different styles of faulting, normal movement with strike slip and strike slip with reverse. These tectonic movements on faults parallel to the Red Sea refer to the tensional forces due to the Red Sea rift system. These events occurred due to a natural tectonic movement, with considering the Khamis Mushait event as an induced event because of the lake behind the Dam. Many previous seismic hazard assessment studies have been conducted in southern Saudi Arabia without considering these recent seismic sources. Thus, our study provides new information related to detecting of new active seismic sources, which contributes to updating studies of seismic risk assessment in this region. In addition, our study pushes us to establish other additional seismic stations around these new seismic sources. This in turn will play a pivotal role in controlling seismic sources and then reassessing the seismic hazard in southern Saudi Arabia.展开更多
Generating different types of defects in heterogeneous catalysts for synergetic promotion of the reactivity and selectivity in catalytic reactions is highly challenging due to the lack of effective theoretical guidanc...Generating different types of defects in heterogeneous catalysts for synergetic promotion of the reactivity and selectivity in catalytic reactions is highly challenging due to the lack of effective theoretical guidance.Herein,we demonstrate a facile strategy to introduce two types of defects into the CuO-ZnO model catalyst,namely oxygen vacancies(OVs)induced by H2 partial reduction and localized amorphous regions(LARs)generated via the ball milling process.Using industrially important Rochow–Müller reaction as a representative,we found OVs predominantly improved the target product selectivity of dimethyldichlorosilane,while LARs significantly increased the conversion of reactant Si.The CuO-ZnO catalyst with optimized OVs and LARs contents achieved the best catalytic property.Theoretical calculation further revealed that LARs promote the generation of the Cu3Si active phase,and OVs impact the electronic structure of the Cu3Si active phase.This work provides a new understanding of the roles of different catalyst defects and a feasible way of engineering the catalyst structure for better catalytic performances.展开更多
PM 2.5 samples were collected in a regional sampling network with three sites in Hong Kong and four sites in the adjacent inland Pearl River Delta (PRD) or Guangdong Province during four months/seasons from 2002–20...PM 2.5 samples were collected in a regional sampling network with three sites in Hong Kong and four sites in the adjacent inland Pearl River Delta (PRD) or Guangdong Province during four months/seasons from 2002–2003. Trans-boundary transport between Hong Kong and the inland PRD is inevitable under the influence of Asian monsoon. In summer, Hong Kong serves as the upwind site of the inland PRD while during other seasons it is under the influence of continental emissions. Previous studies have recognized the importance of using chemical signatures to differentiate local vs. regional contributions to air pollutants in Hong Kong such as the CO/NOx ratio, ratios of different VOC species. In this study, detailed chemical speciation by gas chromatography-mass spectrometry was performed with PM 2.5 samples to identify new chemical signatures to distinguish aerosols in Hong Kong from those from the inland PRD. Since Hong Kong is not influenced by the continental emissions from the inland PRD during summer, comparison focused on chemical data obtained from this season for chemical signatures. The new ratios developed from the current study include LCPI/HCPI ratio of alkanes (0.39 ± 0.02 in Hong Kong vs. 0.78 ± 0.08 in the inland PRD), pyrene to benzo[ghi]perylene ratio (0.97 ± 0.21 in Hong Kong compared to 0.20 ± 0.06 in the inland PRD), and the ratio of 1,2-benzenedioic acid to 1,4-benzenedioic acid (1.8 ± 0.1 in Hong Kong vs. 0.6 ± 0.05 in the inland PRD). Results from this study also revealed that Hong Kong was impacted by ship emissions as reflected by substantially high V/Ni ratio (9 ± 2) while this ratio was about 1–2 at all sites in the inland PRD, which is very close to typical ratios from residual oil combustion.展开更多
Coupling efficiency between the localized surface plasmons(LSPs) of metal nanoparticles(NPs) and incident light dominates the sensitivities of plasmon-based sensing spectroscopies and imaging techniques, e.g., surface...Coupling efficiency between the localized surface plasmons(LSPs) of metal nanoparticles(NPs) and incident light dominates the sensitivities of plasmon-based sensing spectroscopies and imaging techniques, e.g., surfaceenhanced Raman scattering(SERS) spectroscopy. Many endogenous features of metal NPs(e.g., size, shape,aggregation form, etc.) that have strong impacts on their LSPs have been discussed in detail in previous studies.Here, the polarization-tuned electromagnetic(EM) field that facilitates the LSP coupling is fully discussed.Numerical analyses on waveguide-based evanescent fields(WEFs) coupled with the LSPs of dispersed silver nanospheres and silver nano-hemispheres are presented and the applicability of the WEF-LSPs to plasmon-enhanced spectroscopy is discussed. Compared with LSPs under direct light excitation that only provide 3–4 times enhancement of the incidence field, the WEF-LSPs can amplify the electric field intensity about 30–90 times(equaling the enhancement factor of 10~6–10~8 in SERS intensity), which is comparable to the EM amplification of the SERS"hot spot" effect. Importantly, the strongest region of EM enhancement around silver nanospheres can be modulated from the gap region to the side surface simply by switching the incident polarization from TM to TE, which widely extends its sensing applications in surface analysis of monolayer of molecule and macromolecule detections. This technique provides us a unique way to achieve remarkable signal gains in many plasmon-enhanced spectroscopic systems in which LSPs are involved.展开更多
The isothermal local loading forming technology provides a feasible way to form Ti-alloy large-scale rib-web components in aerospace and aviation fields.However,the local loading process forming limit is restricted by...The isothermal local loading forming technology provides a feasible way to form Ti-alloy large-scale rib-web components in aerospace and aviation fields.However,the local loading process forming limit is restricted by forming defects in the transitional region.In this work,the feasibility of controlling forming defects and improving the process forming limit by adjusting die parameters is explored through finite element(FE) simulation.It is found that the common cavum and folding defects in the transitional region are significantly influenced by the fillet radii of left rib and middle rib,respectively.The cavum and folding defects can be effectively controlled by increasing the fillet radii of left rib and middle rib,respectively.The process forming limits considering forming defects in the transitional region are determined by the stepwise searching method under various die parameters.Moreover,the relationship between the process forming limit and die parameters is developed through the response surface methodology(RSM).The developed RSM models suggest that increasing the fillet radii of left and middle ribs is effective to improve the process forming limit during local loading forming of rib-web components.The results will provide technical basis for the design of die parameters and the reduction amount,which is of great importance to control forming defects and improve the process forming limit in local loading forming of Ti-alloy large-scale rib-web components.展开更多
Measurements of peroxyacetyl nitrate(PAN) were made at a Beijing urban site each August from2005 to 2009. Over this 5-year period, the average PAN concentration for August in each year increased from 3(2005) to 11...Measurements of peroxyacetyl nitrate(PAN) were made at a Beijing urban site each August from2005 to 2009. Over this 5-year period, the average PAN concentration for August in each year increased from 3(2005) to 11.7 μg/m3(2007); however, it decreased rapidly in 2008(4.1 μg/m3).Generally, the variation over the 5 years showed a rise in the first part of the study period,followed by a decline. We considered two categories of local and regional air masses in this study, which revealed that the PAN concentration in Beijing was affected mainly by southeastern air masses. The August PAN variation was influenced predominantly by local air masses in 2005,but by 2009 regional air masses had become more important. This study showed the level and variation of PAN in the month of August in 5 consecutive years for the first time, and proved that control measures are useful in decreasing photochemical pollution; hence, these measures are probably feasible for other megacities too. Furthermore, this method of analyzing regional and local impacts might be useful for other studies as well.展开更多
文摘The uncertainty principle is a fundamental principle of quantum mechanics, but its exact mathematical expression cannot obtain correct results when used to solve theoretical problems such as the energy levels of hydrogen atoms, one-dimensional deep potential wells, one-dimensional harmonic oscillators, and double-slit experiments. Even after approximate treatment, the results obtained are not completely consistent with those obtained by solving Schrödinger’s equation. This indicates that further research on the uncertainty principle is necessary. Therefore, using the de Broglie matter wave hypothesis, we quantize the action of an elementary particle in natural coordinates and obtain the quantization condition and a new deterministic relation. Using this quantization condition, we obtain the energy level formulas of an elementary particle in different conditions in a classical way that is completely consistent with the results obtained by solving Schrödinger’s equation. A new physical interpretation is given for the particle eigenfunction independence of probability for an elementary particle: an elementary particle is in a particle state at the space-time point where the action is quantized, and in a wave state in the rest of the space-time region. The space-time points of particle nature and the wave regions of particle motion constitute the continuous trajectory of particle motion. When an elementary particle is in a particle state, it is localized, whereas in the wave state region, it is nonlocalized.
基金Supported by the Natural Science Foundation of Tianjin Science and Technology Bureau,China,No.21JCZDJC01050Tianjin Key Medical Discipline(Specialty)Construction Project,No.TJYXZDXK-034ATianjin Municipal Health Science and Technology Project,No.TJWJ2021ZD003,No.KJ20068,No.KJ20129,and No.TJWJ2022XK029。
文摘Improvements in early screening,new diagnostic techniques,and surgical treatment have led to continuous downward trends in hepatocellular carcinoma(HCC)morbidity and mortality rates.However,high recurrence and refractory cancer after hepatectomy remain important factors affecting the long-term prognosis of HCC.The clinical characteristics and prognosis of recurrent HCC are heterogeneous,and guidelines on treatment strategies for recurrent HCC are lacking.Therapies such as surgical resection,radiofrequency ablation,and transhepatic arterial chemoembolization are effective for tumors confined to the liver,and targeted therapy is a very important treatment for unresectable recurrent HCC with systemic metastasis.With the deepening of the understanding of the immune microenvironment of HCC,blocking immune checkpoints to enhance the antitumor immune response has become a new direction for the treatment of HCC.In addition,improvements in the tumor immune microenvironment caused by local treatment may provide an opportunity to improve the therapeutic effect of HCC treatment.Ongoing and future clinical trial data of combined therapy may develop the new treatment scheme for recurrent HCC.This paper reviews the pattern of recurrent HCC and the characteristics of the immune microenvironment,demonstrates the basis for combining local treatment and systemic treatment,and reports current evidence to better understand current progress and future approaches in the treatment of recurrent HCC.
基金Supported by National Natural Science Foundation of China (No60702037)Research Fund for the Doctoral Program of Higher Education of China (No20070056129)Natural Science Foundation of Tianjin (No09JCYBJC00800)
文摘Sensor localization is crucial for the configuration and applications of wireless sensor network (WSN). A novel distributed localization algorithm, MDS-DC was proposed for wireless sensor network based on multidimensional scaling (MDS) and the shortest path distance correction. In MDS-DC, several local positioning regions with reasonable distribution were firstly constructed by an adaptive search algorithm, which ensures the mergence between the local relative maps of the adjacent local position regions and can reduce the number of common nodes in the network. Then, based on the relationships between the estimated distances and actual distances of anchors, the distance estimation vectors of sensors around anchors were corrected in each local positioning region. During the computations of the local relative coordinates, an iterative process, which is the combination of classical MDS algorithm and SMACOF algorithm, was applied. Finally, the global relative positions or absolute positions of sensors were obtained through merging the relative maps of all local positioning regions. Simulation results show that MDS-DC has better performances in positioning precision, energy efficiency and robustness to range error, which can meet the requirements of applications for sensor localization in WSN.
基金National Natural Science Foundation of China(Grant Nos.51675429,51205313)Fundamental Research Funds for the Central Universities of China(Grant No.3102014JCS05009)111 Project of China(Grant No.B13044)
文摘Computational e ciency and accuracy always conflict with each other in molecular dynamics(MD) simulations. How to enhance the computational e ciency and keep accuracy at the same time is concerned by each corresponding researcher. However, most of the current studies focus on MD algorithms, and if the scale of MD model could be reduced, the algorithms would be more meaningful. A local region molecular dynamics(LRMD) simulation method which can meet these two factors concurrently in nanoscale sliding contacts is developed in this paper. Full MD simulation is used to simulate indentation process before sliding. A criterion called contribution of displacement is presented, which is used to determine the e ective local region in the MD model after indentation. By using the local region, nanoscale sliding contact between a rigid cylindrical tip and an elastic substrate is investigated. Two two?dimensional MD models are presented, and the friction forces from LRMD simulations agree well with that from full MD simulations, which testifies the e ectiveness of the LRMD simulation method for two?dimensional cases. A three?dimensional MD model for sliding contacts is developed then to show the validity of the LRMD simulation method further. Finally, a discussion is carried out by the principles of tribology. In the discussion, two two?dimensional full MD models are used to simulate the nanoscale sliding contact problems. The results indicate that original smaller model will induce higher equivalent scratching depth, and then results in higher friction forces, which will help to explain the mechanism how the LRMD simulation method works. This method can be used to reduce the scale of MD model in large scale simulations, and it will enhance the computational e ciency without losing accuracy during the simula?tion of nanoscale sliding contacts.
文摘This paper attempts to study regional differentiation of cuisine in China and set up a rudimentary framework for regional characteristic of cuisine This framework is mainly concerned with regional school of cuisine (or cuisine systems) and regional dishes It also gives them some explanations of the process of the formation
文摘The cooperative movement has played a very important role in the social and economic development of all countries since 19th eentury's second half. Cooperatives provide health, housing, and banking services; they promote education and gender equality; they protect the environment and workers' rights. According to 2014's data, the total number of cooperatives is 79,486 in Turkey, while the total number of partners of cooperatives is approximately 7.8 million. The research's sample group "Hidirlik Agricultural Development Cooperative" was founded by the wife of the Seferihisar's mayor and six women. It has been a subject of curiousity that the contributions of the cooperative have developed the economy of the region since 2010. Therefore, various questions asked to the president and members of the cooperative, and significant results were obtained. In this research "Interview technique" was used. The fact that within the boundaries of local governments, the establishment of "women's cooperatives" and their active management can be supported with 10 basic criteria for the regional and national development can be predicted. These dimensions: ecological balance and sensitivity, the revival of the tourism sector, the mobility of logistics activities, new investments and increase of land value, the increase of women employment, the increase of healthy living standards, increase of competitiveness and trade earnings, the creation of new brands, widespread of the agricultural sector, and the increase of social and educational level of women. The similiar implementation of "Seferihisar Women's Cooperatives Model" in the research is considered form an important enterprenurship model not only in Turkey but also for all countries.
文摘Nowadays, the disparity of the basic pension in local regions of China can be described as follows: the low level of the unification of the basic pension systems, the large disparity of the level of the basic pension, and unfairness of the enterprises’ payment for the basic pension in different local regions in China. These have already brought many negative influences, which have greatly held back the development of the society and national economy. We should build the basic pension system in all local regions of China as a whole, which can cover all people and decrease the disparity in different local regions in China.
文摘To reduce the computation cost of a combined probabilistic graphical model and a deep neural network in semantic segmentation, the local region condition random field (LRCRF) model is investigated which selectively applies the condition random field (CRF) to the most active region in the image. The full convolutional network structure is optimized with the ResNet-18 structure and dilated convolution to expand the receptive field. The tracking networks are also improved based on SiameseFC by considering the frame relations in consecutive-frame traffic scene maps. Moreover, the segmentation results of the greyscale input data sets are more stable and effective than using the RGB images for deep neural network feature extraction. The experimental results show that the proposed method takes advantage of the image features directly and achieves good real-time performance and high segmentation accuracy.
文摘In China, 10 ethnic minorities with a combined population of over 20 million people are followers of Islam. In Ningxia Hui Autonomous Region, the population is nearly 6 million, a-mong which the Islamic population is about 2 million. In China as a whole, more than 20 million people enjoy eating food prepared according to Islamic guidelines, known as hal'al food.
文摘Recently in 2020, in southern Saudi Arabia three felt earthquakes occurred in Asir region, in the Khamis Mushait, Ahad Rafidah, and AL-Shuqiq area, of magnitude 3.45, 3.1, and 3.5, respectively. The most interesting event was the earthquake that occurred in Khamis Mushait area, along a lake formed behind the Tadhah Dam (~7 km), fearing any damage to the dam’s body and the consequent destruction. Moment tensors for each event were computed for determining fault plane solutions, seismic moment, moment magnitude (Mw) and the CLVD ratio. In addition, the frequency contents in the waveforms of each event were identified. The obtained focal mechanisms represent different styles of faulting, normal movement with strike slip and strike slip with reverse. These tectonic movements on faults parallel to the Red Sea refer to the tensional forces due to the Red Sea rift system. These events occurred due to a natural tectonic movement, with considering the Khamis Mushait event as an induced event because of the lake behind the Dam. Many previous seismic hazard assessment studies have been conducted in southern Saudi Arabia without considering these recent seismic sources. Thus, our study provides new information related to detecting of new active seismic sources, which contributes to updating studies of seismic risk assessment in this region. In addition, our study pushes us to establish other additional seismic stations around these new seismic sources. This in turn will play a pivotal role in controlling seismic sources and then reassessing the seismic hazard in southern Saudi Arabia.
基金support from the National Natural Science Foundation of China(Nos.21878301 and 21978299)the Open Research Fund of State Key Laboratory of Multiphase Complex Systems(No.MPCS-2021-D-08)+4 种基金GRINM Group.Y.J.J.thanks the financial support from the Research Foundation for Advanced Talents of Beijing Technology and Business University(No.19008020159)X.L.C.thanks the financial support from the project for improving the research ability of postgraduate from Beijing Technology and Business University(No.19008022056)L.W.X.thanks the financial support from the Research Foundation for Youth Scholars of Beijing Technology and Business University(No.QNJJ2022-22)Z.Y.Z.thanks the financial support of Guangdong Provincial Key Laboratory of Materials and Technologies for Energy Conversion(MATEC)Guangdong Technion-Israel Institute of Technology and Guangdong Key Discipline Fund(2022)for this collaboration。
文摘Generating different types of defects in heterogeneous catalysts for synergetic promotion of the reactivity and selectivity in catalytic reactions is highly challenging due to the lack of effective theoretical guidance.Herein,we demonstrate a facile strategy to introduce two types of defects into the CuO-ZnO model catalyst,namely oxygen vacancies(OVs)induced by H2 partial reduction and localized amorphous regions(LARs)generated via the ball milling process.Using industrially important Rochow–Müller reaction as a representative,we found OVs predominantly improved the target product selectivity of dimethyldichlorosilane,while LARs significantly increased the conversion of reactant Si.The CuO-ZnO catalyst with optimized OVs and LARs contents achieved the best catalytic property.Theoretical calculation further revealed that LARs promote the generation of the Cu3Si active phase,and OVs impact the electronic structure of the Cu3Si active phase.This work provides a new understanding of the roles of different catalyst defects and a feasible way of engineering the catalyst structure for better catalytic performances.
基金sponsored by Hong Kong Jockey Club Charities Trust, Castle Peak Power Co. Ltd., the Environ- mental Protection Department of the Hong Kong Special Administrative Region and the Shell Hong Kong Ltd. through Civic Exchange
文摘PM 2.5 samples were collected in a regional sampling network with three sites in Hong Kong and four sites in the adjacent inland Pearl River Delta (PRD) or Guangdong Province during four months/seasons from 2002–2003. Trans-boundary transport between Hong Kong and the inland PRD is inevitable under the influence of Asian monsoon. In summer, Hong Kong serves as the upwind site of the inland PRD while during other seasons it is under the influence of continental emissions. Previous studies have recognized the importance of using chemical signatures to differentiate local vs. regional contributions to air pollutants in Hong Kong such as the CO/NOx ratio, ratios of different VOC species. In this study, detailed chemical speciation by gas chromatography-mass spectrometry was performed with PM 2.5 samples to identify new chemical signatures to distinguish aerosols in Hong Kong from those from the inland PRD. Since Hong Kong is not influenced by the continental emissions from the inland PRD during summer, comparison focused on chemical data obtained from this season for chemical signatures. The new ratios developed from the current study include LCPI/HCPI ratio of alkanes (0.39 ± 0.02 in Hong Kong vs. 0.78 ± 0.08 in the inland PRD), pyrene to benzo[ghi]perylene ratio (0.97 ± 0.21 in Hong Kong compared to 0.20 ± 0.06 in the inland PRD), and the ratio of 1,2-benzenedioic acid to 1,4-benzenedioic acid (1.8 ± 0.1 in Hong Kong vs. 0.6 ± 0.05 in the inland PRD). Results from this study also revealed that Hong Kong was impacted by ship emissions as reflected by substantially high V/Ni ratio (9 ± 2) while this ratio was about 1–2 at all sites in the inland PRD, which is very close to typical ratios from residual oil combustion.
基金National Natural Science Foundation of China(NSFC)(21373096,21573087,21573092,91441105)National Instrumentation Program(NIP)of the Ministry of Science and Technology of the People’s Republic of China(MOST)(2011YQ03012408)Science and Technology Development Program Funded Projects of Jilin Province
文摘Coupling efficiency between the localized surface plasmons(LSPs) of metal nanoparticles(NPs) and incident light dominates the sensitivities of plasmon-based sensing spectroscopies and imaging techniques, e.g., surfaceenhanced Raman scattering(SERS) spectroscopy. Many endogenous features of metal NPs(e.g., size, shape,aggregation form, etc.) that have strong impacts on their LSPs have been discussed in detail in previous studies.Here, the polarization-tuned electromagnetic(EM) field that facilitates the LSP coupling is fully discussed.Numerical analyses on waveguide-based evanescent fields(WEFs) coupled with the LSPs of dispersed silver nanospheres and silver nano-hemispheres are presented and the applicability of the WEF-LSPs to plasmon-enhanced spectroscopy is discussed. Compared with LSPs under direct light excitation that only provide 3–4 times enhancement of the incidence field, the WEF-LSPs can amplify the electric field intensity about 30–90 times(equaling the enhancement factor of 10~6–10~8 in SERS intensity), which is comparable to the EM amplification of the SERS"hot spot" effect. Importantly, the strongest region of EM enhancement around silver nanospheres can be modulated from the gap region to the side surface simply by switching the incident polarization from TM to TE, which widely extends its sensing applications in surface analysis of monolayer of molecule and macromolecule detections. This technique provides us a unique way to achieve remarkable signal gains in many plasmon-enhanced spectroscopic systems in which LSPs are involved.
基金the support of the National Natural Science Foundation of China(Nos.51605388,51675433)111 Project(B08040)+2 种基金the Research Fund of the State Key Laboratory of Solidification Processing(NWPU)in China(Grant No.131-QP-2015)the Fundamental Research Funds for the Central Universitiesthe Open Research Fund of State Key Laboratory of Materials Processing and Die&Mold Technology at Huazhong University of Science and Technology
文摘The isothermal local loading forming technology provides a feasible way to form Ti-alloy large-scale rib-web components in aerospace and aviation fields.However,the local loading process forming limit is restricted by forming defects in the transitional region.In this work,the feasibility of controlling forming defects and improving the process forming limit by adjusting die parameters is explored through finite element(FE) simulation.It is found that the common cavum and folding defects in the transitional region are significantly influenced by the fillet radii of left rib and middle rib,respectively.The cavum and folding defects can be effectively controlled by increasing the fillet radii of left rib and middle rib,respectively.The process forming limits considering forming defects in the transitional region are determined by the stepwise searching method under various die parameters.Moreover,the relationship between the process forming limit and die parameters is developed through the response surface methodology(RSM).The developed RSM models suggest that increasing the fillet radii of left and middle ribs is effective to improve the process forming limit during local loading forming of rib-web components.The results will provide technical basis for the design of die parameters and the reduction amount,which is of great importance to control forming defects and improve the process forming limit in local loading forming of Ti-alloy large-scale rib-web components.
基金supported by the Beijing Council of Science and Technology (Nos. HB200504-6, HB200504-2)the Natural Science Fund Project of the Beijing Municipal Government (No. 8072014)+1 种基金the National High Technology Development Plan (863 Project) of China (No. 2006AA06A301)supported by the special fund provided by the State Key Joint Laboratory of Environmental Simulation and Pollution Control (14Y04ESPCP), Peking University
文摘Measurements of peroxyacetyl nitrate(PAN) were made at a Beijing urban site each August from2005 to 2009. Over this 5-year period, the average PAN concentration for August in each year increased from 3(2005) to 11.7 μg/m3(2007); however, it decreased rapidly in 2008(4.1 μg/m3).Generally, the variation over the 5 years showed a rise in the first part of the study period,followed by a decline. We considered two categories of local and regional air masses in this study, which revealed that the PAN concentration in Beijing was affected mainly by southeastern air masses. The August PAN variation was influenced predominantly by local air masses in 2005,but by 2009 regional air masses had become more important. This study showed the level and variation of PAN in the month of August in 5 consecutive years for the first time, and proved that control measures are useful in decreasing photochemical pollution; hence, these measures are probably feasible for other megacities too. Furthermore, this method of analyzing regional and local impacts might be useful for other studies as well.