Vietnam's manufacturing and processing companies areop timistic about business prospects in the second quarter(Q2)of this year,according to a recent survey by the National Statis-tics Office(Gso).The results of th...Vietnam's manufacturing and processing companies areop timistic about business prospects in the second quarter(Q2)of this year,according to a recent survey by the National Statis-tics Office(Gso).The results of the survey indicate that 45.8%of bustnesses anticipate improved business performance in Q22025 compared to Ql while 39.2%expect stability and l5%foresee encountering more difficulties ahead.展开更多
The statistics of the China natural gas industry prosperity index showed that the China natural gas industry prosperity index was 337.66 in the 4th quarter of 2024,up 4.1%from the 3rd quarter of 2024,a stably prospero...The statistics of the China natural gas industry prosperity index showed that the China natural gas industry prosperity index was 337.66 in the 4th quarter of 2024,up 4.1%from the 3rd quarter of 2024,a stably prosperous state in the short term and a very prosperous state in the medium to long term;the prosperity index of natural gas production companies was 494.89 in the 4th quarter of 2024,up 5.2%from the 3rd quarter of 2024,an increasingly prosperous state in the short term and a very prosperous state in the medium to long term.展开更多
The statistics of the China natural gas industry prosperity index showed that the China natural gas industry prosperity index was 346.98 in the 1st quarter of 2025,up 2.8%from the 4th quarter of 2024,a stably prospero...The statistics of the China natural gas industry prosperity index showed that the China natural gas industry prosperity index was 346.98 in the 1st quarter of 2025,up 2.8%from the 4th quarter of 2024,a stably prosperous state in the short term and a very prosperous state in the medium to long term;the prosperity index of natural gas production companies was 517.14 in the 1st quarter of 2025,up 4.5%from the 4th quarter of 2024,an increasingly prosperous state in the short term and a very prosperous state in the medium to long term;the prosperity index of natural gas sales companies was 208.26 in the 1st quarter of 2025,down 0.9%from the 4th quarter of 2024.The gas sales company has experienced a decline in prosperity in short term,yet this does not alter its long-term upward trend.In the medium to long term,it remains in a highly prosperous state.;the prosperity trend index of the natural gas industry in the coming year for the 1st quarter of 2025 was 735.21,up 3.9%from the 4th quarter of 2024,a very prosperous state,indicating that natural gas industry experts are optimistic about the natural gas industry’s prosperity trend in the coming year.See Fig.1 and Table 1 for details.展开更多
The statistics of the China natural gas industry prosperity index showed that the China natural gas industry prosperity index was 357.68 in the 2nd quarter of 2025,up 3.1% from the 1st quarter of 2025,a stably prosper...The statistics of the China natural gas industry prosperity index showed that the China natural gas industry prosperity index was 357.68 in the 2nd quarter of 2025,up 3.1% from the 1st quarter of 2025,a stably prosperous state in the short term and a very prosperous state in the medium to long term;the prosperity index of natural gas production companies was 542.01 in the 2nd quarter of 2025,up 4.8% from the 1st quarter of 2025,an increasingly prosperous state in the short term and a very prosperous state in the medium to long term;the prosperity index of natural gas sales companies was 209.06 in the 2nd quarter of 2025,up 0.4% from the 1st quarter of 2025,an increasing prosperity in the short term and a prosperous state in the medium to long term;the prosperity trend index of the natural gas industry in the coming year for the 2nd quarter of 2025 was 765.70,up 4.1% from the 1st quarter of 2025,a very prosperous state,indicating that natural gas industry experts are optimistic about the natural gas industry’s prosperity trend in the coming year.See Fig.1 and Table 1 for details.展开更多
The statistics of the China natural gas industry prosperity Index showed that the China natural gas industry Prosperity Index was 312.46 in the 2nd quarter of 2024,up 3.2%from the 1st quarter of 2024,a stably prospero...The statistics of the China natural gas industry prosperity Index showed that the China natural gas industry Prosperity Index was 312.46 in the 2nd quarter of 2024,up 3.2%from the 1st quarter of 2024,a stably prosperous state in the short term and a very prosperous state in the medium to long term;the prosperity index of natural gas production companies was 447.03 in the 2nd quarter of 2024,up 4.3%from the 1st quarter of 2024.展开更多
The statistics of the China matural gas industry prosperity index showed that the China natural gas industry prosperity index was 302.84 in the 1st quarter of 2024,up 3.6%from the 4th quarter of 2023,a stably prospero...The statistics of the China matural gas industry prosperity index showed that the China natural gas industry prosperity index was 302.84 in the 1st quarter of 2024,up 3.6%from the 4th quarter of 2023,a stably prosperous state in the short term and a very prosperous state in the medium to long term;the prosperity index of natural gas production companies was 428.78 in the 1st quarter of 2024.展开更多
The Last Quarter of the Moon is a novel written by Chi Zijian,which describes the life of the Ewenki ethnic minority in northeast China.The novel has received wide attention for its profound theme and unique narrative...The Last Quarter of the Moon is a novel written by Chi Zijian,which describes the life of the Ewenki ethnic minority in northeast China.The novel has received wide attention for its profound theme and unique narrative style.Defamiliarization is a technique commonly used in literary creation.By breaking the conventional expression mode and changing the conventional view,readers can have new feelings and understandings.The original text of The Last Quarter of the Moon describes the life of the Ewenki minority in China,which has a strong defamiliarization effect.In the English version,the translator adopts various methods to reproduce this defamiliarization.Through the analysis of its English translation,this paper discusses the defamiliarization embodied in it and the two translation methods used by the translator to reproduce the defamiliarization of the original text:alienizing translation and hybridization.It is found that the translation successfully retains the unique charm of the original text by means of language and cultural defamiliarization,enabling English readers to obtain a new reading experience,and revealing the important reasons why the English translation of The Last Quarter of the Moon can be successfully translated and spread in the Western world.展开更多
The statistics of the China natural gas industry prosperity index showed that the China natural gas industry prosperity index was 324.34 in the 3rd quarter of 2024,up 3.8%from the 2nd quarter of 2024,a stably prospero...The statistics of the China natural gas industry prosperity index showed that the China natural gas industry prosperity index was 324.34 in the 3rd quarter of 2024,up 3.8%from the 2nd quarter of 2024,a stably prosperous state in the short term and a very prosperous state in the medium to long term.展开更多
Turkiye maintains its 4th place in the world home textile exports.Home textile manufacturers continue to produce and export despite the negativities such as regional wars,global economic crisis,fluctuations in exchang...Turkiye maintains its 4th place in the world home textile exports.Home textile manufacturers continue to produce and export despite the negativities such as regional wars,global economic crisis,fluctuations in exchange rates and cost increases.In 2024,the home textile sector,whose exports decreased from time to time,started the last quarter of the year with an increase in exports.Turkiye’s home textile exports fell by 8.7%in the JanuaryOctober period of 2024.展开更多
New textile materials are being developed at a rapid pace,breaking the boundaries between traditional textile technologies and offering new functional,environmental and comfort benefits.In the first quarter of 2024,th...New textile materials are being developed at a rapid pace,breaking the boundaries between traditional textile technologies and offering new functional,environmental and comfort benefits.In the first quarter of 2024,the textile industry has ushered in a wave of innovation.These new materials not only bring new development opportunities for the textile industry,but also more possibilities for our lives.This article summarizes some of the recently released new textile materials,their application prospects and impact on the industry.展开更多
On January 8th,the China Chamber of Commerce for Import and Export of Textiles released data showing that in the fourth quarter,China’s textile and clothing exports gradually stabilised.The proportion of intermediate...On January 8th,the China Chamber of Commerce for Import and Export of Textiles released data showing that in the fourth quarter,China’s textile and clothing exports gradually stabilised.The proportion of intermediate exports in textile and clothing exports continued to rise,providing a new impetus for the substantial expansion of exports to traditional markets and international supply chain cooperation.展开更多
A series of regular and irregular wave experiments are conducted to study the reflective and transmitting performances of quarter circular breakwater （QCB） in comparison with those of semi-circular breakwater （SCB...A series of regular and irregular wave experiments are conducted to study the reflective and transmitting performances of quarter circular breakwater （QCB） in comparison with those of semi-circular breakwater （SCB）. Based on regular wave tests, the reflection and transmission characteristics of QCB are analyzed and a few influencing factors are investigated. Then, the wave energy dissipation as wave passing over the breakwater is discussed based on the hydraulic coefficients of QCB and SCB. In irregular wave experiments, the reflection coefficients of QCB and their spectrums are studied. Finally, the comparisons between the experimental results and numerical simulations for QCB under regular and irregular wave conditions are presented.展开更多
Quarter circular breakwater （QCB） is a new-type breakwater developed from senti-circular breakwater （SCB）. The superstructure of QCB is composed of a quarter circular front wall, a horizontal base slab and a verti...Quarter circular breakwater （QCB） is a new-type breakwater developed from senti-circular breakwater （SCB）. The superstructure of QCB is composed of a quarter circular front wall, a horizontal base slab and a vertical rear wall. The width of QCB＇ s base slab is about half that of SCB, which makes QCB suitable to be used on relatively finn soil foundation. The numerical wave flume based on the Reynolds averaged Navier-Stokes equations for impressible viscosity fluid is adopted in this paper to simulate the hydraulic performances of QCB. Since the geometry of both breakwaters is similar and SCB has been studied in depth, the hydraulic performances of QCB are given in comparison with those of SCB.展开更多
A series of physical tests are conducted to examine the characteristics of the wave loading exerted on circular-front breakwaters by regular waves. It is found that the wave trough instead of wave crest plays a major ...A series of physical tests are conducted to examine the characteristics of the wave loading exerted on circular-front breakwaters by regular waves. It is found that the wave trough instead of wave crest plays a major role in the failure of submerged circular caissons due to seaward sliding. The difference in the behavior of seaward and shoreward horizontal wave forces is explained based on the variations of dynamic pressure with wave parameters. A wave load model is proposed based on a modified first-order solution for the dynamic pressure on submerged circular-front caissons under a wave trough. This wave loading model is very useful for engineering design. Further studies are needed to include model uncertainties in the reliability assessment of the breakwater.展开更多
In this paper, a transmissive terahertz(THz) quarter wave plate(QWP) has been proposed to realize the linear-to-circular polarization conversion in terahertz range. This quarter wave plate is composed of two dielectri...In this paper, a transmissive terahertz(THz) quarter wave plate(QWP) has been proposed to realize the linear-to-circular polarization conversion in terahertz range. This quarter wave plate is composed of two dielectric layers and one metallic layer with asymmetric cross slots. In the range of 0.894-1.378 THz, the axis ratio of proposed device is less than 3 d B, and its polarization conversion efficiency is more than 45%. The distributions of surface currents and electromagnetic field density had been proposed to understand the physical mechanism of proposed device. The linear-to-circular polarization conversion can be attributed to the asymmetric transmission along slots. Finally, the simulation results are validated by experiments in terahertz region. The proposed device has simple geometry and good performance, which can be used as a key component in applications of terahertz communications, terahertz imaging and terahertz sensing.展开更多
To reveal the generation mechanism of the quarter buckle in the process of hot-rolled temper rolling,the elastic–plastic finite element method is used to calculate the deformation of the roll and the strip during the...To reveal the generation mechanism of the quarter buckle in the process of hot-rolled temper rolling,the elastic–plastic finite element method is used to calculate the deformation of the roll and the strip during the temper rolling.The change of the cross section of the strip and the distribution of the longitudinal stress are analysed under different bending forces to obtain the boundary conditions of the quarter buckle.The generation of the quarter buckle is further analysed from the bending and contact flattening of the roll system and the elastic recovery of the strip after rolling.We found that the quarter buckle is closely related to the high-order distribution of the contact flattening between the work roll and the strip and is less affected by the bending deformation of the roll and the contact flattening between the rolls.Finally,a new work roll contour of the locally variable crown is proposed to change the distribution of contact flattening between the work roll and the strip.It is verified through theoretical calculations and industrial applications that the new contour can effectively improve the quarter buckle.展开更多
This article deals with designing a broadband and high efficiency metal multi-layer dielectric grating （MMDG） used to compress and stretch an ultrashort laser pulse. The diffraction characteristics of the IVIMDG are...This article deals with designing a broadband and high efficiency metal multi-layer dielectric grating （MMDG） used to compress and stretch an ultrashort laser pulse. The diffraction characteristics of the IVIMDG are analysed by using the rigorous coupled-wave method. The multi-layer dielectric used as the reflective mirror is made up of non- quarter-wave coatings. Taking the diffraction efficiency of the -1 order as the value of merit function, the parameters such as groove depth, residual thickness, duty cycle, and reflective mirror are optimized to obtain broadband and high diffraction efficiency. The optimized MMDG shows an ultra-broadband working spectrum with the average efficiency exceeding 97% over 160 nm wavelength centred at 1053 nm and TE polarization. The optimized MMDG should be useful for chirped pulse amplification.展开更多
An air damper possesses the advantages that there are no long term changes in the damping properties, there is no dependence on working temperature and additionally, it has less manufacturing and maintenance costs. As...An air damper possesses the advantages that there are no long term changes in the damping properties, there is no dependence on working temperature and additionally, it has less manufacturing and maintenance costs. As such, an air damper has been designed and developed based on the Maxwell type model concept in the approach of Nishihara and Asami [1]. The cylinder-piston and air-tank type damper characteristics such as air damping ratio and air spring rate have been studied by changing the length and diameter of the capillary pipe between the air cylinder and the air tank, operating air pressure and the air tank volume. A SDOF quarter-car vehicle suspension system using the developed air enclosed cylinder-piston and air-tank type damper has been analyzed for its motion transmissibility characteristics. Optimal values of the air damping ratio at various values of air spring rate have been determined for minimum motion transmissibility of the sprung mass. An experimental setup has been developed for SDOF quarter-car suspension system model using the developed air enclosed cylinder-piston and air-tank type damper to determine the motion transmissibility characteristics of the sprung mass. An attendant air pressure control system has been designed to vary air damping in the developed air damper. The results of the theoretical analysis have been compared with the experimental analysis.展开更多
文摘Vietnam's manufacturing and processing companies areop timistic about business prospects in the second quarter(Q2)of this year,according to a recent survey by the National Statis-tics Office(Gso).The results of the survey indicate that 45.8%of bustnesses anticipate improved business performance in Q22025 compared to Ql while 39.2%expect stability and l5%foresee encountering more difficulties ahead.
文摘The statistics of the China natural gas industry prosperity index showed that the China natural gas industry prosperity index was 337.66 in the 4th quarter of 2024,up 4.1%from the 3rd quarter of 2024,a stably prosperous state in the short term and a very prosperous state in the medium to long term;the prosperity index of natural gas production companies was 494.89 in the 4th quarter of 2024,up 5.2%from the 3rd quarter of 2024,an increasingly prosperous state in the short term and a very prosperous state in the medium to long term.
文摘The statistics of the China natural gas industry prosperity index showed that the China natural gas industry prosperity index was 346.98 in the 1st quarter of 2025,up 2.8%from the 4th quarter of 2024,a stably prosperous state in the short term and a very prosperous state in the medium to long term;the prosperity index of natural gas production companies was 517.14 in the 1st quarter of 2025,up 4.5%from the 4th quarter of 2024,an increasingly prosperous state in the short term and a very prosperous state in the medium to long term;the prosperity index of natural gas sales companies was 208.26 in the 1st quarter of 2025,down 0.9%from the 4th quarter of 2024.The gas sales company has experienced a decline in prosperity in short term,yet this does not alter its long-term upward trend.In the medium to long term,it remains in a highly prosperous state.;the prosperity trend index of the natural gas industry in the coming year for the 1st quarter of 2025 was 735.21,up 3.9%from the 4th quarter of 2024,a very prosperous state,indicating that natural gas industry experts are optimistic about the natural gas industry’s prosperity trend in the coming year.See Fig.1 and Table 1 for details.
文摘The statistics of the China natural gas industry prosperity index showed that the China natural gas industry prosperity index was 357.68 in the 2nd quarter of 2025,up 3.1% from the 1st quarter of 2025,a stably prosperous state in the short term and a very prosperous state in the medium to long term;the prosperity index of natural gas production companies was 542.01 in the 2nd quarter of 2025,up 4.8% from the 1st quarter of 2025,an increasingly prosperous state in the short term and a very prosperous state in the medium to long term;the prosperity index of natural gas sales companies was 209.06 in the 2nd quarter of 2025,up 0.4% from the 1st quarter of 2025,an increasing prosperity in the short term and a prosperous state in the medium to long term;the prosperity trend index of the natural gas industry in the coming year for the 2nd quarter of 2025 was 765.70,up 4.1% from the 1st quarter of 2025,a very prosperous state,indicating that natural gas industry experts are optimistic about the natural gas industry’s prosperity trend in the coming year.See Fig.1 and Table 1 for details.
文摘The statistics of the China natural gas industry prosperity Index showed that the China natural gas industry Prosperity Index was 312.46 in the 2nd quarter of 2024,up 3.2%from the 1st quarter of 2024,a stably prosperous state in the short term and a very prosperous state in the medium to long term;the prosperity index of natural gas production companies was 447.03 in the 2nd quarter of 2024,up 4.3%from the 1st quarter of 2024.
文摘The statistics of the China matural gas industry prosperity index showed that the China natural gas industry prosperity index was 302.84 in the 1st quarter of 2024,up 3.6%from the 4th quarter of 2023,a stably prosperous state in the short term and a very prosperous state in the medium to long term;the prosperity index of natural gas production companies was 428.78 in the 1st quarter of 2024.
基金The study reported here was supported by the Zhejiang Social Science Planning Project(Fund No.22NDJC046YB).
文摘The Last Quarter of the Moon is a novel written by Chi Zijian,which describes the life of the Ewenki ethnic minority in northeast China.The novel has received wide attention for its profound theme and unique narrative style.Defamiliarization is a technique commonly used in literary creation.By breaking the conventional expression mode and changing the conventional view,readers can have new feelings and understandings.The original text of The Last Quarter of the Moon describes the life of the Ewenki minority in China,which has a strong defamiliarization effect.In the English version,the translator adopts various methods to reproduce this defamiliarization.Through the analysis of its English translation,this paper discusses the defamiliarization embodied in it and the two translation methods used by the translator to reproduce the defamiliarization of the original text:alienizing translation and hybridization.It is found that the translation successfully retains the unique charm of the original text by means of language and cultural defamiliarization,enabling English readers to obtain a new reading experience,and revealing the important reasons why the English translation of The Last Quarter of the Moon can be successfully translated and spread in the Western world.
文摘The statistics of the China natural gas industry prosperity index showed that the China natural gas industry prosperity index was 324.34 in the 3rd quarter of 2024,up 3.8%from the 2nd quarter of 2024,a stably prosperous state in the short term and a very prosperous state in the medium to long term.
文摘Turkiye maintains its 4th place in the world home textile exports.Home textile manufacturers continue to produce and export despite the negativities such as regional wars,global economic crisis,fluctuations in exchange rates and cost increases.In 2024,the home textile sector,whose exports decreased from time to time,started the last quarter of the year with an increase in exports.Turkiye’s home textile exports fell by 8.7%in the JanuaryOctober period of 2024.
文摘New textile materials are being developed at a rapid pace,breaking the boundaries between traditional textile technologies and offering new functional,environmental and comfort benefits.In the first quarter of 2024,the textile industry has ushered in a wave of innovation.These new materials not only bring new development opportunities for the textile industry,but also more possibilities for our lives.This article summarizes some of the recently released new textile materials,their application prospects and impact on the industry.
文摘On January 8th,the China Chamber of Commerce for Import and Export of Textiles released data showing that in the fourth quarter,China’s textile and clothing exports gradually stabilised.The proportion of intermediate exports in textile and clothing exports continued to rise,providing a new impetus for the substantial expansion of exports to traditional markets and international supply chain cooperation.
基金supported by the National Natural Science Foundation of China (Grant No. 50779045)the Open Foundation of State Key Laboratory of Hydraulics and Mountain River Engineering (Grant No. 0710)+2 种基金the National Science Foundation for Post-Doctoral Scientists of China (Grant No. 20080440681)the Natural Science Foundation of Tianjin, China (Grant No. 10JCYBJC03700)the Scientific and Technologic Development Foundation of the Higher Education Institutions of Tianjin,China (Grant No. 20080906)
文摘A series of regular and irregular wave experiments are conducted to study the reflective and transmitting performances of quarter circular breakwater （QCB） in comparison with those of semi-circular breakwater （SCB）. Based on regular wave tests, the reflection and transmission characteristics of QCB are analyzed and a few influencing factors are investigated. Then, the wave energy dissipation as wave passing over the breakwater is discussed based on the hydraulic coefficients of QCB and SCB. In irregular wave experiments, the reflection coefficients of QCB and their spectrums are studied. Finally, the comparisons between the experimental results and numerical simulations for QCB under regular and irregular wave conditions are presented.
基金supported by the National Natural Science Foundation of China(Grant No.50779045)
文摘Quarter circular breakwater （QCB） is a new-type breakwater developed from senti-circular breakwater （SCB）. The superstructure of QCB is composed of a quarter circular front wall, a horizontal base slab and a vertical rear wall. The width of QCB＇ s base slab is about half that of SCB, which makes QCB suitable to be used on relatively finn soil foundation. The numerical wave flume based on the Reynolds averaged Navier-Stokes equations for impressible viscosity fluid is adopted in this paper to simulate the hydraulic performances of QCB. Since the geometry of both breakwaters is similar and SCB has been studied in depth, the hydraulic performances of QCB are given in comparison with those of SCB.
基金financially supported by the Open Fund of the State Key Laboratory of Hydraulic Engineering Simulation and Safety from Tianjin University(Gtant No.HESS-1310)the Natural Science Foundation of Tianjin,China(Gtant No.14JCYBJC22100)+5 种基金the National Natural Science Foundation of China(Gtant No.51509178)supported by the State Scholarship Fund of China Scholarship Council(Gtant No.201308120008)supported by the Physical Oceanography Program of National Science Foundation(Grant No.1436642)the Maine Sea Grant and NOAA for Grant No.NA10OAR4170072part of EFRaCC project funded by the British Council under its Global Innovation Initiativethe open fund research at the State Key Laboratory of Hydraulics and Mountain River at Sichuan University(Grant No.SKHL1311)
文摘A series of physical tests are conducted to examine the characteristics of the wave loading exerted on circular-front breakwaters by regular waves. It is found that the wave trough instead of wave crest plays a major role in the failure of submerged circular caissons due to seaward sliding. The difference in the behavior of seaward and shoreward horizontal wave forces is explained based on the variations of dynamic pressure with wave parameters. A wave load model is proposed based on a modified first-order solution for the dynamic pressure on submerged circular-front caissons under a wave trough. This wave loading model is very useful for engineering design. Further studies are needed to include model uncertainties in the reliability assessment of the breakwater.
基金supported by the New Direction Cultivation Project of Chongqing University of Posts and Telecommunications(No.A2014-116)
文摘In this paper, a transmissive terahertz(THz) quarter wave plate(QWP) has been proposed to realize the linear-to-circular polarization conversion in terahertz range. This quarter wave plate is composed of two dielectric layers and one metallic layer with asymmetric cross slots. In the range of 0.894-1.378 THz, the axis ratio of proposed device is less than 3 d B, and its polarization conversion efficiency is more than 45%. The distributions of surface currents and electromagnetic field density had been proposed to understand the physical mechanism of proposed device. The linear-to-circular polarization conversion can be attributed to the asymmetric transmission along slots. Finally, the simulation results are validated by experiments in terahertz region. The proposed device has simple geometry and good performance, which can be used as a key component in applications of terahertz communications, terahertz imaging and terahertz sensing.
基金This work was financially supported by the National Natural Science Foundation of China(52004029)the Open Foundation of Engineering Research Centre for Metallurgical Automation and Measurement Technology of Ministry of Education(MADTOF-2019A01)the Postdoctoral Science Foundation of China(2021M690352).
文摘To reveal the generation mechanism of the quarter buckle in the process of hot-rolled temper rolling,the elastic–plastic finite element method is used to calculate the deformation of the roll and the strip during the temper rolling.The change of the cross section of the strip and the distribution of the longitudinal stress are analysed under different bending forces to obtain the boundary conditions of the quarter buckle.The generation of the quarter buckle is further analysed from the bending and contact flattening of the roll system and the elastic recovery of the strip after rolling.We found that the quarter buckle is closely related to the high-order distribution of the contact flattening between the work roll and the strip and is less affected by the bending deformation of the roll and the contact flattening between the rolls.Finally,a new work roll contour of the locally variable crown is proposed to change the distribution of contact flattening between the work roll and the strip.It is verified through theoretical calculations and industrial applications that the new contour can effectively improve the quarter buckle.
基金Project supported by the Program of Qingdao Municipal Science and Technology Bureau, China (Grant No. 12-1-4-2-(15)-jch)the National Natural Science Foundation of China (Grant Nos. 11274188 and 10904080)the Taishan Scholars Program of Shandong Province, China
文摘This article deals with designing a broadband and high efficiency metal multi-layer dielectric grating （MMDG） used to compress and stretch an ultrashort laser pulse. The diffraction characteristics of the IVIMDG are analysed by using the rigorous coupled-wave method. The multi-layer dielectric used as the reflective mirror is made up of non- quarter-wave coatings. Taking the diffraction efficiency of the -1 order as the value of merit function, the parameters such as groove depth, residual thickness, duty cycle, and reflective mirror are optimized to obtain broadband and high diffraction efficiency. The optimized MMDG shows an ultra-broadband working spectrum with the average efficiency exceeding 97% over 160 nm wavelength centred at 1053 nm and TE polarization. The optimized MMDG should be useful for chirped pulse amplification.
文摘An air damper possesses the advantages that there are no long term changes in the damping properties, there is no dependence on working temperature and additionally, it has less manufacturing and maintenance costs. As such, an air damper has been designed and developed based on the Maxwell type model concept in the approach of Nishihara and Asami [1]. The cylinder-piston and air-tank type damper characteristics such as air damping ratio and air spring rate have been studied by changing the length and diameter of the capillary pipe between the air cylinder and the air tank, operating air pressure and the air tank volume. A SDOF quarter-car vehicle suspension system using the developed air enclosed cylinder-piston and air-tank type damper has been analyzed for its motion transmissibility characteristics. Optimal values of the air damping ratio at various values of air spring rate have been determined for minimum motion transmissibility of the sprung mass. An experimental setup has been developed for SDOF quarter-car suspension system model using the developed air enclosed cylinder-piston and air-tank type damper to determine the motion transmissibility characteristics of the sprung mass. An attendant air pressure control system has been designed to vary air damping in the developed air damper. The results of the theoretical analysis have been compared with the experimental analysis.
