Wellbore breakout is one of the critical issues in drilling due to the fact that the related problems result in additional costs and impact the drilling scheme severely.However,the majority of such wellbore breakout a...Wellbore breakout is one of the critical issues in drilling due to the fact that the related problems result in additional costs and impact the drilling scheme severely.However,the majority of such wellbore breakout analyses were based on continuum mechanics.In addition to failure in intact rocks,wellbore breakouts can also be initiated along natural discontinuities,e.g.weak planes and fractures.Furthermore,the conventional models in wellbore breakouts with uniform distribution fractures could not reflect the real drilling situation.This paper presents a fully coupled hydro-mechanical model of the SB-X well in the Tarim Basin,China for evaluating wellbore breakouts in heavily fractured rocks under anisotropic stress states using the distinct element method(DEM)and the discrete fracture network(DFN).The developed model was validated against caliper log measurement,and its stability study was carried out by stress and displacement analyses.A parametric study was performed to investigate the effects of the characteristics of fracture distribution(orientation and length)on borehole stability by sensitivity studies.Simulation results demonstrate that the increase of the standard deviation of orientation when the fracture direction aligns parallel or perpendicular to the principal stress direction aggravates borehole instability.Moreover,an elevation in the average fracture length causes the borehole failure to change from the direction of the minimum in-situ horizontal principal stress(i.e.the direction of wellbore breakouts)towards alternative directions,ultimately leading to the whole wellbore failure.These findings provide theoretical insights for predicting wellbore breakouts in heavily fractured rocks.展开更多
Against the backdrop of increasingly prominent global environmental issues,heavily polluting enterprises(HPPs)urgently need to find a path to green transformation that achieves sustainable development and overcomes ef...Against the backdrop of increasingly prominent global environmental issues,heavily polluting enterprises(HPPs)urgently need to find a path to green transformation that achieves sustainable development and overcomes efficiency challenges.Based on data on mergers and acquisitions of HPPs from 2010 to 2023,this article explores the direct impact and mechanisms of green mergers and acquisitions(GMAs)on enterprises green transformation.Research findings are as follows:(1)GMAs significantly promote the green transformation of HPPs,a conclusion that is robust across various tests.(2)Internal control and green innovation quality serve as partial and chain mediators,respectively,in the relationship between GMAs and the green transformation of HPPs.(3)Media pressure negatively affects the impact of GMAs on internal control.(4)The heterogeneity analysis shows that the GMAs of enterprises in the eastern region,non-state-owned enterprises,large enterprises,and enterprises in the electricity,heat,gas,and water production and supply industries have a more obvious impact on green transformation.These findings elucidate the mechanisms through which GMAs drive the green transformation of HPPs and offer empirical insights into supporting the sustainable development of such enterprises in China.展开更多
Water pollution in the Taihu Lake Basin has been the focus of attention in China and abroad for a long time, due to its position in the forefront of urban development in China. Based on data gathering and processing f...Water pollution in the Taihu Lake Basin has been the focus of attention in China and abroad for a long time, due to its position in the forefront of urban development in China. Based on data gathering and processing from 84 monitoring sections in this heavily polluted area, this study first analyzes spatial patterns of urbanization and the distribution of river water pollution, and then uses the GeoDa bivariate spatial autocorrelation model to investigate the spatial correlation between urbanization and river water pollution at the scale of township units. The results show that urbanization has adverse impacts on water pollution, and the influence varies in different levels of development areas. The urban township units have the highest level of urbanization and highest pollution, but the best water quality; the suburban units have lower level of urbanization, but higher pollution and worse water quality; however the rural units have the lowest level of urbanization and lowest pollution, mainly affected by upstream pollution, but worst water quality. Lastly, urban and rural planning committees, while actively promoting the process of development in the region, should gradually resolve the issue of pollution control lagging behind urban life and urban develop- ment, giving priority to construction of centralized sewage treatment facilities and associated pipeline network coverage in the rural areas and suburban areas.展开更多
A compact linearly polarized, low-noise, narrow-linewidth, single-frequency fiber laser at 1950nm is demonstrated. This compact fiber laser is based on a 21-mm-long homemade Tm3＋-doped germanate glass fiber. Over 100...A compact linearly polarized, low-noise, narrow-linewidth, single-frequency fiber laser at 1950nm is demonstrated. This compact fiber laser is based on a 21-mm-long homemade Tm3＋-doped germanate glass fiber. Over 100-mW stable continuous-wave single transverse and longitudinal mode lasing at 195Ohm are achieved. The measured relative intensity noise is less than -135dB/Hz at frequencies over 5 MHz. The signal-to-noise ratio of the laser is larger than 72dB, and the laser linewidth is less than 6kHz, while the obtained linear polarization extinction ratio is higher than 22 dB.展开更多
The deteriorating water quality in the Taihu Lake Basin has attracted widespread attention for many years, and is correlated with a sharp increase in the quantity of pollutant discharge such as agricultural fertilizer...The deteriorating water quality in the Taihu Lake Basin has attracted widespread attention for many years, and is correlated with a sharp increase in the quantity of pollutant discharge such as agricultural fertilizers and industrial wastewater. In this study, several factors were selected for evaluating and regionalizing the water environmental capacity by ArcG1S spatial analysis, including geomor- phologic characteristics, water quality goals, water body accessibility, water-dilution channels, and current water quality. Then, the spa- tial optimization of agriculture and industry was adjusted through overlay analysis, based on the balance between industrial space and water environmental capacity. The results show that the water environmental capacity gradually decreases from the west to the east, in contrast, the pollution caused by industrial and agricultural clustering is distributes along Taihu Lake, Gehu Lake and urban districts. The analysis of the agricultural space focuses on optimizing key protected areas of the Taihu Lake Basin, and the shores of Gehu Lake, optimally adjusting the second protected areas of the Taihu Lake Basin, and generally adjusting the urban areas of Changzhou and Wuxi cities. The analysis of industrial space focuses on optimizing the downtowns of Changzhou and Wuxi cities, optimally adjusting key protected areas and second protected areas of the Taihu Lake Basin, and generally adjusting the south and southwest of Gehu Lake. Lastly, some schemes of industrial and agricultural layouts and policies for the direction of industrial and agricultural development were proposed, reflecting a correlation between industry and agriculture and the water environment.展开更多
The plasmonic property of heavily doped p-type silicon is studied here.Although most of the plasmonic devices use metal-insulator-metal(MIM)waveguide in order to support the propagation of surface plasmon polaritons(S...The plasmonic property of heavily doped p-type silicon is studied here.Although most of the plasmonic devices use metal-insulator-metal(MIM)waveguide in order to support the propagation of surface plasmon polaritons(SPPs),metals that possess a number of challenges in loss management,polarization response,nanofabrication etc.On the other hand,heavily doped p-type silicon shows similar plasmonic properties like metals and also enables us to overcome the challenges possessed by metals.For numerical simulation,heavily doped p-silicon is mathematically modeled and the theoretically obtained relative permittivity is compared with the experimental value.A waveguide is formed with the p-silicon-air interface instead of the metal-air interface.Formation and propagation of SPPs similar to MIM waveguides are observed.展开更多
Since the London fog in 1952, numerous epidemioLogical studies have revealed that both short-term and long-term exposure to air pollutants is associated with the development of diseases[1]. Up to date, the assessment ...Since the London fog in 1952, numerous epidemioLogical studies have revealed that both short-term and long-term exposure to air pollutants is associated with the development of diseases[1]. Up to date, the assessment of air quality on health and air quality standard establishment in developing countries were mainly relied on extrapolation based on the results from long-term cohort studies conducted in Europe and North America.展开更多
Oxygen precipitates in heavily Sb-doped silicon after rapid thermal process (RTP) in Ar ambient were investigated by RTP at high temperature following annealing at 800 ℃ for 4 h and 1000 ℃ for 16 h. RTP temperature ...Oxygen precipitates in heavily Sb-doped silicon after rapid thermal process (RTP) in Ar ambient were investigated by RTP at high temperature following annealing at 800 ℃ for 4 h and 1000 ℃ for 16 h. RTP temperature and cooling rates were changed from 1200 to 1260 ℃ and from 10 to 100 ℃·s-1, respectively. The experiment results show that high density of oxygen precipitates is observed in heavily Sb-doped wafer. It is found that the oxygen precipitates in heavily Sb-doped silicon are enhanced at high cooling rate.展开更多
Due to ineffectiveness of routine IR-absorption method for determinahon of intershtial oxygen in heavily doped silicon, a 'peak-height' method has been dcveloped. The phosphorus-doped CZ-Si with n=(7.l～l2)...Due to ineffectiveness of routine IR-absorption method for determinahon of intershtial oxygen in heavily doped silicon, a 'peak-height' method has been dcveloped. The phosphorus-doped CZ-Si with n=(7.l～l2)× 10~17cm^(-3) was taken as sample for characterization. The calculation results at 300 K and 10 K were ptesented in detail. The'peak-height' method is much simpler than 'short-baseline' and 'curved-baseline' methods.展开更多
An M-shaped interface was observed in the top part of Φ76. 2 mm , (111) , dislocation-free, heavily Sb-doped Si single crystals, which is beneficial for crystals to keep dislocation-free condition at the beginning of...An M-shaped interface was observed in the top part of Φ76. 2 mm , (111) , dislocation-free, heavily Sb-doped Si single crystals, which is beneficial for crystals to keep dislocation-free condition at the beginning ofbody growth. Effects of seed rotation, crucible rotation , crown shape and growth rate on M-shaed interfacewere studied. Under proper conditions, impurity core length can be shortened from 6 cm to 1 cm , the yield israised by more than 5 %.展开更多
The anodic voltammetric curves of heavily doped n-Si in HF solution, on which three different regions have emerged, and were plotted, A porous silicon layer with fine morphology was formed in linear region.
We perform systematic thermal conductivity measurements on heavily hole-doped Ba1-xKxFe2As2 single crystals with 0.747 ≤ x ≤ 0.974. At x=0.747, the K0/T is negligible, indicating a nodeless superconducting gap. A sm...We perform systematic thermal conductivity measurements on heavily hole-doped Ba1-xKxFe2As2 single crystals with 0.747 ≤ x ≤ 0.974. At x=0.747, the K0/T is negligible, indicating a nodeless superconducting gap. A small residual linear term K0/T （=0.035 m W.K-2 cm-1） appears at xz0.826, and it increases slowly up to x=0.974, followed by a substantial increase of more than 20 times to of K0/T clearly shows that the nodal gap appears near x surface topology. The small values of K0/T from x=0.826 the pure KFe2As2 （x=1.0）. This doping dependence = 0.8, possibly associated with the change of Fermi to 0.974 are consistent with the Y-shaped nodal s- wave gap recently revealed by angle-resolved photoemission spectroscopy experiments at x=0.9. Furthermore, the substantial increase of K0/T from x=0.974 to 1.0 is inconsistent with a symmetry-imposed d-wave gap in KFe2 As2, and a possible nodal gap structure in KFe2As2 is discussed.展开更多
The first permanent molar as the first permanent tooth in the mouth and with a general insufficient oral hygiene of the children, is commonly subject to significant compromise which may arise due to caries or endodont...The first permanent molar as the first permanent tooth in the mouth and with a general insufficient oral hygiene of the children, is commonly subject to significant compromise which may arise due to caries or endodontic complication, or from developmental anomalies such as hypoplasia. Compromised teeth with questionable prognosis may result in short- and long-term clinical dilemmas. The aim of this research is to highlight the factors that require careful consideration when a compromised UFPM is detected and the importance of timely UFPM extraction to ensure the mesial drift of the upper second permanent molar (USPM) to fulfill the space of the extracted UFPM without any orthodontic intervention. For this purpose 52 heavily destructed UFPMs were extracted at age of 10.5 years old, 44 (84.6%) USPMs erupted exactly distal to the second premolar while only 7 (13.4%) USPMs erupted 1 mm distal to the second premolar. Clinically it is recommended to extract the heavily destructed upper first molars at age of 10.5 years old to ensure the complete closure of the extraction space by the passive mesial drift of upper second permanent molar.展开更多
In many industries,there is a growing demand for semiconductor pressure sensors capable of operating in harsh environments with extremely high and low temperatures and high vibrations.Utilizing the piezoresistive effe...In many industries,there is a growing demand for semiconductor pressure sensors capable of operating in harsh environments with extremely high and low temperatures and high vibrations.Utilizing the piezoresistive effect of heavily doped N-type 4H-SiC,we proposed a family design of eight pressure sensor chip structures featuring different diaphragm shapes of circles and squares,along with different piezoresistor configurations.The 4H-SiC piezoresistive pressure sensor was developed using micro-electromechanical systems(MEMS)technology and encapsulated in a leadless package structure via low-stress connection achieved by glass frit sintering.The 4H-SiC pressure sensor demonstrates impressive performance,exhibiting an accuracy of 0.18%FSO and a temperature tolerance range from−50 to 600°C,with a temperature coefficient of zero output as low as 0.08%/°C at 600°C.Furthermore,the developed sensor shows remarkable stability under conditions of high-temperature vibration coupling.The advancement of this family of 4H-SiC pressure sensors provides a promising solution for pressure measurement in harsh industrial environments.展开更多
Addressing pollution caused by economic development,especially the overcapacity of polluting enterprises,is crucial for promoting sustainable economic growth.Targeted environmental policies are essential for strengthe...Addressing pollution caused by economic development,especially the overcapacity of polluting enterprises,is crucial for promoting sustainable economic growth.Targeted environmental policies are essential for strengthening environmental constraints on enterprises and enhancing the effectiveness of regulatory instruments.This study focused on the Environmental Credit Evaluation policy by examining its potential to improve capacity utilization and assessing its broader impact on heavily polluting enterprises.It constructed a time-varying difference-in-difference-in-differences model using panel data from 965 industrial enterprises from 2009 to 2019.The findings reveal that,in comparison with their non-heavily polluting counterparts,heavily polluting enterprises subject to the policy demonstrated significant improvements in capacity utilization.Heavily polluting enterprises that experienced a substantial increase in financing costs also exhibited a marked reduction in inefficient investment,without negatively affecting innovation investments or output.展开更多
The control ofblack and odorous substances in sediments is of crucial importance to improve the urban ecological landscape and to restore water environments accordingly.In this study,chemical oxidation by the oxidants...The control ofblack and odorous substances in sediments is of crucial importance to improve the urban ecological landscape and to restore water environments accordingly.In this study,chemical oxidation by the oxidants NaClO,H2O2,and KMnO4 was proposed to achieve rapid control of black and odorous substances in heavily-polluted sediments.Results indicate that NaClO and KMnO4 are effective at removing Fe(II)and acid volatile sulfides.The removal efficiencies of Fe(II)and AVS were determined to be 45.2%,94.1%,and 93.7%,89.5%after 24-h exposure to NaClO and KMnO4 at 0.2 mmol/g,respectively.Additionally,rapid oxidation might accelerate the release of pollutants from sediment.The release of organic matters and phosphorus with the maximum ratios of 22.1%and 51.2%was observed upon NaClO oxidation at 0.4 mmol/g.Moreover,the introduction of oxidants contributed to changes in the microbial community composition in sediment.After oxidation by NaClO and KMnO4 at 0.4 mmol/g,the Shannon index decreased from 6.72 to 5.19 and 4.95,whereas the OTU numbers decreased from 2904 to 1677 and 1553,respectively.Comparatively,H2O2 showed a lower effect on the removal of black and odorous substances,pollutant release,and changes in sediment microorganisms.This study illustrates the effects of oxidant addition on the characteristics of heavily polluted sediments and shows that chemical oxidants may be an option to achieve rapid control of black and odorous substances prior to remediation of water environments.展开更多
The magnetism in heavily Dy doped La0.7-xDyxSr0.3MnO3(0.40≤x≤0.70)system is studied in this paper.The M-T relation seems to be complicated with the increase of x.For sample with x=0.40,AFM behavior exists at T≤TN a...The magnetism in heavily Dy doped La0.7-xDyxSr0.3MnO3(0.40≤x≤0.70)system is studied in this paper.The M-T relation seems to be complicated with the increase of x.For sample with x=0.40,AFM behavior exists at T≤TN and M-T curves under zero field cooling(ZFC)and field cooling(FC)exhibit typical behavior of spincluster glass state above TN.For the sample with x=0.50,the M-T curve under ZFC exhibits a valley at a low temperature while the M-T curve under FC exhibits the negative magnetization below TN.For samples with x=0.60,0.70,their ZFC M-T curves are similar to that of x=0.50,but the FC M-T curves do not exhibit negative values any more.All the peculiar phenomena above are well explained by Néel double-lattice model combined with M-H relation at typical temperatures.The molecular field theory fits well the negative magnetization for x=0.50.展开更多
We obtain an ahnost sure central limit theorem(ASCLT)for heavily trimmed sums.We also prove a function-typed ASCLT under the same conditions that assure measurable functions to satisfy the ASCLT for the partial sums o...We obtain an ahnost sure central limit theorem(ASCLT)for heavily trimmed sums.We also prove a function-typed ASCLT under the same conditions that assure measurable functions to satisfy the ASCLT for the partial sums of i.i.d,random variables with EX_1=0,EX_1~2=1.展开更多
基金supported by National Natural Science Foundation of China(Grant Nos.52074312 and 52211530097)CNPC Science and Technology Innovation Foundation(Grant No.2021DQ02-0505).
文摘Wellbore breakout is one of the critical issues in drilling due to the fact that the related problems result in additional costs and impact the drilling scheme severely.However,the majority of such wellbore breakout analyses were based on continuum mechanics.In addition to failure in intact rocks,wellbore breakouts can also be initiated along natural discontinuities,e.g.weak planes and fractures.Furthermore,the conventional models in wellbore breakouts with uniform distribution fractures could not reflect the real drilling situation.This paper presents a fully coupled hydro-mechanical model of the SB-X well in the Tarim Basin,China for evaluating wellbore breakouts in heavily fractured rocks under anisotropic stress states using the distinct element method(DEM)and the discrete fracture network(DFN).The developed model was validated against caliper log measurement,and its stability study was carried out by stress and displacement analyses.A parametric study was performed to investigate the effects of the characteristics of fracture distribution(orientation and length)on borehole stability by sensitivity studies.Simulation results demonstrate that the increase of the standard deviation of orientation when the fracture direction aligns parallel or perpendicular to the principal stress direction aggravates borehole instability.Moreover,an elevation in the average fracture length causes the borehole failure to change from the direction of the minimum in-situ horizontal principal stress(i.e.the direction of wellbore breakouts)towards alternative directions,ultimately leading to the whole wellbore failure.These findings provide theoretical insights for predicting wellbore breakouts in heavily fractured rocks.
基金supported by the National Natural Science Foundation of China“Reconstruction of Competitive Advantage of China's High-tech Industry from the Perspective of Dual Value Chain”(Grant No.71972063)Natural Science Foundation of Heilongjiang Province“Innovation Decision-making and Performance of Green Factories in Heilongjiang Province under the Dual Carbon Target:an Incentive Environmental Regulation Perspective”(Grant No.JJ2022LH0765)Key R&D Program(Soft Science Project)of Shandong Province,China“Research on the Development Status and Countermeasures of High-tech Enterprises in Shandong Province”(Grant No.2023RZB03024).
文摘Against the backdrop of increasingly prominent global environmental issues,heavily polluting enterprises(HPPs)urgently need to find a path to green transformation that achieves sustainable development and overcomes efficiency challenges.Based on data on mergers and acquisitions of HPPs from 2010 to 2023,this article explores the direct impact and mechanisms of green mergers and acquisitions(GMAs)on enterprises green transformation.Research findings are as follows:(1)GMAs significantly promote the green transformation of HPPs,a conclusion that is robust across various tests.(2)Internal control and green innovation quality serve as partial and chain mediators,respectively,in the relationship between GMAs and the green transformation of HPPs.(3)Media pressure negatively affects the impact of GMAs on internal control.(4)The heterogeneity analysis shows that the GMAs of enterprises in the eastern region,non-state-owned enterprises,large enterprises,and enterprises in the electricity,heat,gas,and water production and supply industries have a more obvious impact on green transformation.These findings elucidate the mechanisms through which GMAs drive the green transformation of HPPs and offer empirical insights into supporting the sustainable development of such enterprises in China.
基金Knowledge Innovation Program of the Chinese Academy of Sciences,No.KZCX2-EW-315 National Water Pollution Control and Management Technology Major Projects,No.20082X07101-002+2 种基金 National Natural Science Foundation of China,No.41130750 135 Strategic Development Planning Project of Nanjing Institute of Geography and Limnology,CAS,No.2012135006 Fund from the State Key Laboratory of Lake Science and Environment,Nanjing Institute of Geography and Limnology,CAS
文摘Water pollution in the Taihu Lake Basin has been the focus of attention in China and abroad for a long time, due to its position in the forefront of urban development in China. Based on data gathering and processing from 84 monitoring sections in this heavily polluted area, this study first analyzes spatial patterns of urbanization and the distribution of river water pollution, and then uses the GeoDa bivariate spatial autocorrelation model to investigate the spatial correlation between urbanization and river water pollution at the scale of township units. The results show that urbanization has adverse impacts on water pollution, and the influence varies in different levels of development areas. The urban township units have the highest level of urbanization and highest pollution, but the best water quality; the suburban units have lower level of urbanization, but higher pollution and worse water quality; however the rural units have the lowest level of urbanization and lowest pollution, mainly affected by upstream pollution, but worst water quality. Lastly, urban and rural planning committees, while actively promoting the process of development in the region, should gradually resolve the issue of pollution control lagging behind urban life and urban develop- ment, giving priority to construction of centralized sewage treatment facilities and associated pipeline network coverage in the rural areas and suburban areas.
基金Supported by the National High-Technology Research and Development Program of China under Grant Nos 2013AA031502 and 2014AA041902the National Natural Science Foundation of China under Grant Nos 11174085,51132004,and 51302086+3 种基金the Natural Science Foundation of Guangdong Province under Grant Nos S2011030001349 and S20120011380the China National Funds for Distinguished Young Scientists under Grant No 61325024the Science and Technology Project of Guangdong Province under Grant No 2013B090500028the ’Cross and Cooperative’ Science and Technology Innovation Team Project of Chinese Academy of Sciences under Grant No 2012-119
文摘A compact linearly polarized, low-noise, narrow-linewidth, single-frequency fiber laser at 1950nm is demonstrated. This compact fiber laser is based on a 21-mm-long homemade Tm3＋-doped germanate glass fiber. Over 100-mW stable continuous-wave single transverse and longitudinal mode lasing at 195Ohm are achieved. The measured relative intensity noise is less than -135dB/Hz at frequencies over 5 MHz. The signal-to-noise ratio of the laser is larger than 72dB, and the laser linewidth is less than 6kHz, while the obtained linear polarization extinction ratio is higher than 22 dB.
基金Under the auspices of National Natural Science Foundation of China (No. 41130750,70703033)'135' Strategic Development Planning Project of Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences (No. 2012135006)
文摘The deteriorating water quality in the Taihu Lake Basin has attracted widespread attention for many years, and is correlated with a sharp increase in the quantity of pollutant discharge such as agricultural fertilizers and industrial wastewater. In this study, several factors were selected for evaluating and regionalizing the water environmental capacity by ArcG1S spatial analysis, including geomor- phologic characteristics, water quality goals, water body accessibility, water-dilution channels, and current water quality. Then, the spa- tial optimization of agriculture and industry was adjusted through overlay analysis, based on the balance between industrial space and water environmental capacity. The results show that the water environmental capacity gradually decreases from the west to the east, in contrast, the pollution caused by industrial and agricultural clustering is distributes along Taihu Lake, Gehu Lake and urban districts. The analysis of the agricultural space focuses on optimizing key protected areas of the Taihu Lake Basin, and the shores of Gehu Lake, optimally adjusting the second protected areas of the Taihu Lake Basin, and generally adjusting the urban areas of Changzhou and Wuxi cities. The analysis of industrial space focuses on optimizing the downtowns of Changzhou and Wuxi cities, optimally adjusting key protected areas and second protected areas of the Taihu Lake Basin, and generally adjusting the south and southwest of Gehu Lake. Lastly, some schemes of industrial and agricultural layouts and policies for the direction of industrial and agricultural development were proposed, reflecting a correlation between industry and agriculture and the water environment.
文摘The plasmonic property of heavily doped p-type silicon is studied here.Although most of the plasmonic devices use metal-insulator-metal(MIM)waveguide in order to support the propagation of surface plasmon polaritons(SPPs),metals that possess a number of challenges in loss management,polarization response,nanofabrication etc.On the other hand,heavily doped p-type silicon shows similar plasmonic properties like metals and also enables us to overcome the challenges possessed by metals.For numerical simulation,heavily doped p-silicon is mathematically modeled and the theoretically obtained relative permittivity is compared with the experimental value.A waveguide is formed with the p-silicon-air interface instead of the metal-air interface.Formation and propagation of SPPs similar to MIM waveguides are observed.
基金supported by the National Basic Research Program (973 program) of China (2011CB503802)the Gong-Yi Program of the Chinese Ministry of Environmental Protection (201209008)+2 种基金Shanghai Municipal Committee of Science and Technology (12dz1202602)Shanghai Health Bureau (GWDTR201212)the Scholarship Award for Excellent Doctoral Student granted by Ministry of Education (2011)
文摘Since the London fog in 1952, numerous epidemioLogical studies have revealed that both short-term and long-term exposure to air pollutants is associated with the development of diseases[1]. Up to date, the assessment of air quality on health and air quality standard establishment in developing countries were mainly relied on extrapolation based on the results from long-term cohort studies conducted in Europe and North America.
基金Projects supported by the National Natural Science Foundation of China (50572022), Natural Science Foundation of Tianjin, and Natural Science Foundation of Hebei Province (E2005000057)
文摘Oxygen precipitates in heavily Sb-doped silicon after rapid thermal process (RTP) in Ar ambient were investigated by RTP at high temperature following annealing at 800 ℃ for 4 h and 1000 ℃ for 16 h. RTP temperature and cooling rates were changed from 1200 to 1260 ℃ and from 10 to 100 ℃·s-1, respectively. The experiment results show that high density of oxygen precipitates is observed in heavily Sb-doped wafer. It is found that the oxygen precipitates in heavily Sb-doped silicon are enhanced at high cooling rate.
文摘Due to ineffectiveness of routine IR-absorption method for determinahon of intershtial oxygen in heavily doped silicon, a 'peak-height' method has been dcveloped. The phosphorus-doped CZ-Si with n=(7.l～l2)× 10~17cm^(-3) was taken as sample for characterization. The calculation results at 300 K and 10 K were ptesented in detail. The'peak-height' method is much simpler than 'short-baseline' and 'curved-baseline' methods.
文摘An M-shaped interface was observed in the top part of Φ76. 2 mm , (111) , dislocation-free, heavily Sb-doped Si single crystals, which is beneficial for crystals to keep dislocation-free condition at the beginning ofbody growth. Effects of seed rotation, crucible rotation , crown shape and growth rate on M-shaed interfacewere studied. Under proper conditions, impurity core length can be shortened from 6 cm to 1 cm , the yield israised by more than 5 %.
文摘The anodic voltammetric curves of heavily doped n-Si in HF solution, on which three different regions have emerged, and were plotted, A porous silicon layer with fine morphology was formed in linear region.
基金Supported by the National Basic Research Program under Grant Nos 2012CB821402 and 2015CB921401the National Natural Science Foundation of China+1 种基金the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher LearningSTCSM of China(No 15XD1500200)
文摘We perform systematic thermal conductivity measurements on heavily hole-doped Ba1-xKxFe2As2 single crystals with 0.747 ≤ x ≤ 0.974. At x=0.747, the K0/T is negligible, indicating a nodeless superconducting gap. A small residual linear term K0/T （=0.035 m W.K-2 cm-1） appears at xz0.826, and it increases slowly up to x=0.974, followed by a substantial increase of more than 20 times to of K0/T clearly shows that the nodal gap appears near x surface topology. The small values of K0/T from x=0.826 the pure KFe2As2 （x=1.0）. This doping dependence = 0.8, possibly associated with the change of Fermi to 0.974 are consistent with the Y-shaped nodal s- wave gap recently revealed by angle-resolved photoemission spectroscopy experiments at x=0.9. Furthermore, the substantial increase of K0/T from x=0.974 to 1.0 is inconsistent with a symmetry-imposed d-wave gap in KFe2 As2, and a possible nodal gap structure in KFe2As2 is discussed.
文摘The first permanent molar as the first permanent tooth in the mouth and with a general insufficient oral hygiene of the children, is commonly subject to significant compromise which may arise due to caries or endodontic complication, or from developmental anomalies such as hypoplasia. Compromised teeth with questionable prognosis may result in short- and long-term clinical dilemmas. The aim of this research is to highlight the factors that require careful consideration when a compromised UFPM is detected and the importance of timely UFPM extraction to ensure the mesial drift of the upper second permanent molar (USPM) to fulfill the space of the extracted UFPM without any orthodontic intervention. For this purpose 52 heavily destructed UFPMs were extracted at age of 10.5 years old, 44 (84.6%) USPMs erupted exactly distal to the second premolar while only 7 (13.4%) USPMs erupted 1 mm distal to the second premolar. Clinically it is recommended to extract the heavily destructed upper first molars at age of 10.5 years old to ensure the complete closure of the extraction space by the passive mesial drift of upper second permanent molar.
基金supported by the National Natural Science Foundation of China(62401451,62131017)the Postdoctoral Fellowship Program of China Postdoctoral Science Foundation(GZB20230584)the China Postdoctoral Science Foundation(2024M762579)。
文摘In many industries,there is a growing demand for semiconductor pressure sensors capable of operating in harsh environments with extremely high and low temperatures and high vibrations.Utilizing the piezoresistive effect of heavily doped N-type 4H-SiC,we proposed a family design of eight pressure sensor chip structures featuring different diaphragm shapes of circles and squares,along with different piezoresistor configurations.The 4H-SiC piezoresistive pressure sensor was developed using micro-electromechanical systems(MEMS)technology and encapsulated in a leadless package structure via low-stress connection achieved by glass frit sintering.The 4H-SiC pressure sensor demonstrates impressive performance,exhibiting an accuracy of 0.18%FSO and a temperature tolerance range from−50 to 600°C,with a temperature coefficient of zero output as low as 0.08%/°C at 600°C.Furthermore,the developed sensor shows remarkable stability under conditions of high-temperature vibration coupling.The advancement of this family of 4H-SiC pressure sensors provides a promising solution for pressure measurement in harsh industrial environments.
基金support from the Major Program of the National Social Science Foundation of China(No.21&ZD109).
文摘Addressing pollution caused by economic development,especially the overcapacity of polluting enterprises,is crucial for promoting sustainable economic growth.Targeted environmental policies are essential for strengthening environmental constraints on enterprises and enhancing the effectiveness of regulatory instruments.This study focused on the Environmental Credit Evaluation policy by examining its potential to improve capacity utilization and assessing its broader impact on heavily polluting enterprises.It constructed a time-varying difference-in-difference-in-differences model using panel data from 965 industrial enterprises from 2009 to 2019.The findings reveal that,in comparison with their non-heavily polluting counterparts,heavily polluting enterprises subject to the policy demonstrated significant improvements in capacity utilization.Heavily polluting enterprises that experienced a substantial increase in financing costs also exhibited a marked reduction in inefficient investment,without negatively affecting innovation investments or output.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.51820105011,51578537 and 51778603)the Chinese Academy of Sciences(No.QYZDY-SSWDQC004).
文摘The control ofblack and odorous substances in sediments is of crucial importance to improve the urban ecological landscape and to restore water environments accordingly.In this study,chemical oxidation by the oxidants NaClO,H2O2,and KMnO4 was proposed to achieve rapid control of black and odorous substances in heavily-polluted sediments.Results indicate that NaClO and KMnO4 are effective at removing Fe(II)and acid volatile sulfides.The removal efficiencies of Fe(II)and AVS were determined to be 45.2%,94.1%,and 93.7%,89.5%after 24-h exposure to NaClO and KMnO4 at 0.2 mmol/g,respectively.Additionally,rapid oxidation might accelerate the release of pollutants from sediment.The release of organic matters and phosphorus with the maximum ratios of 22.1%and 51.2%was observed upon NaClO oxidation at 0.4 mmol/g.Moreover,the introduction of oxidants contributed to changes in the microbial community composition in sediment.After oxidation by NaClO and KMnO4 at 0.4 mmol/g,the Shannon index decreased from 6.72 to 5.19 and 4.95,whereas the OTU numbers decreased from 2904 to 1677 and 1553,respectively.Comparatively,H2O2 showed a lower effect on the removal of black and odorous substances,pollutant release,and changes in sediment microorganisms.This study illustrates the effects of oxidant addition on the characteristics of heavily polluted sediments and shows that chemical oxidants may be an option to achieve rapid control of black and odorous substances prior to remediation of water environments.
基金Supported by the State Key Project of Fundamental Research of China(Grant No.2007CB925001)the State Key Development Program for BasicResearch of China(Grant No.001CB610604)+1 种基金the Natural Science Foundation of Anhui Higher Education Institutions of China(Grant Nos.2006KJ266B and ZD2007003-1)Anhui Key Laboratory of Spin Electron and Nanomaterials(Cultivating Base)
文摘The magnetism in heavily Dy doped La0.7-xDyxSr0.3MnO3(0.40≤x≤0.70)system is studied in this paper.The M-T relation seems to be complicated with the increase of x.For sample with x=0.40,AFM behavior exists at T≤TN and M-T curves under zero field cooling(ZFC)and field cooling(FC)exhibit typical behavior of spincluster glass state above TN.For the sample with x=0.50,the M-T curve under ZFC exhibits a valley at a low temperature while the M-T curve under FC exhibits the negative magnetization below TN.For samples with x=0.60,0.70,their ZFC M-T curves are similar to that of x=0.50,but the FC M-T curves do not exhibit negative values any more.All the peculiar phenomena above are well explained by Néel double-lattice model combined with M-H relation at typical temperatures.The molecular field theory fits well the negative magnetization for x=0.50.
基金Supported by the National Natural Science Foundation of China(No.10071003)Beijing Municipal Education Commission(KM200310028107)
文摘We obtain an ahnost sure central limit theorem(ASCLT)for heavily trimmed sums.We also prove a function-typed ASCLT under the same conditions that assure measurable functions to satisfy the ASCLT for the partial sums of i.i.d,random variables with EX_1=0,EX_1~2=1.
