We report on the fabrication of circular cladding waveguides with cross-section diameters of 60−120μm in Pr:YAG crystal by applying femtosecond laser inscription.The fabricated waveguides present 2D guidance on the c...We report on the fabrication of circular cladding waveguides with cross-section diameters of 60−120μm in Pr:YAG crystal by applying femtosecond laser inscription.The fabricated waveguides present 2D guidance on the cross-section and fairly low propagation losses.Multiple high-order guiding modes are observed in waveguides with different diameters.Corresponding simulation results reveal the origin of a specific kind of guiding modes.Confocal micro-Raman(μ-Raman)experiments demonstrate the modification effects in femtosecond laser affected areas and ascertain the refractive index induced guiding mechanism.In addition,luminescence emission properties of Pr3+ions at waveguide volume are well preserved during the femtosecond laser inscription process,which may result in a potential high-power visible waveguide laser.展开更多
Ultrafast laser inscription(ULI)inside semiconductors offers new perspectives for 3D monolithic structures to be fabricated and new functionalities to be added in electronic and photonic microdevices.However,important...Ultrafast laser inscription(ULI)inside semiconductors offers new perspectives for 3D monolithic structures to be fabricated and new functionalities to be added in electronic and photonic microdevices.However,important challenges remain because of nonlinear effects such as strong plasma generation that distort the energy delivery at the focal point when exposing these materials to intense infrared light.Up to now,the successful technological demonstrations have primarily concentrated on silicon(Si).In this paper,we target at another important semiconductor:gallium arsenide(GaAs).With nonlinearities higher than those of Si,3D-machining of GaAs with femtosecond pulses becomes even harder.However,we show that the difficulty can be circumvented by burst-mode irradiation.We generate and apply trains of pulses at terahertz repetition rates for efficient pulse-to-pulse accumulation of laser-induced free carriers in the focal region,while avoiding an overdose of prefocal excitations.The superior performance of burst-mode irradiation is confirmed by a comparative study conducted with infrared luminescence microscopy.The results indicate a successful reduction of the plasma density in the prefocal region so that higher pulse energy reaches the focal spot.The same method is applied to identify optimum irradiation conditions considering particular cases such as asymmetric pulse trains and aberrated beams.With 64-pulse trains,we successfully manage to cross the writing threshold providing a solution for ULI inside GaAs.The application potential is finally illustrated with a stealth dicing demonstration by taking benefit of the burst mode.The irradiation method opens wide possibilities for 3D structuring inside GaAs by ULI.展开更多
A teaching model based on constructivism is proposed in this paper. The model contains five teaching steps, e.g. interpretation teaching, questioning- dialogue, knowledge and skills teaching, discussion- collaboration...A teaching model based on constructivism is proposed in this paper. The model contains five teaching steps, e.g. interpretation teaching, questioning- dialogue, knowledge and skills teaching, discussion- collaboration and field training. Practice proves that it can effectively improve the training efficiency of the training of English guides of stone inscription relics and enhance their interpretation quality and English skills.展开更多
Oracle bone inscriptions (OBI) has important historical and cultural values. The traditional OBI research methods are at a choke point, and the research method using computer science and information technology has ope...Oracle bone inscriptions (OBI) has important historical and cultural values. The traditional OBI research methods are at a choke point, and the research method using computer science and information technology has opened up the way of OBI information processing. However, it faces some problems, such as large but not centralized knowledge system, long learning cycle, learning difficulties, being difficult to obtain resources, inconsistent format, low retrieval accuracy, and low knowledge sharing and reuse. To solve these problems, it designs an OBI big data research resource management and intelligent knowledge service platform. Its goal is to make full use of OBI big data characteristics and use the knowledge engineering technology to build an OBI knowledge ecosystem. The experiment results show that the platform proposed provides effective one-stop knowledge management and knowledge service.展开更多
The detection of Oracle Bone Inscriptions (OBIs) is one of the most fundamental tasks in the study of Oracle Bone, which aims to locate the positions of OBIs on rubbing images. The existing methods are based on the sc...The detection of Oracle Bone Inscriptions (OBIs) is one of the most fundamental tasks in the study of Oracle Bone, which aims to locate the positions of OBIs on rubbing images. The existing methods are based on the scheme of anchor boxes, involving complex network design and a great number of anchor boxes. In order to overcome the problem, this paper proposes a simpler but more effective OBIs detector by using an anchor-free scheme, where shape-adaptive Gaussian kernels are employed to represent the spatial regions of different OBIs. More specifically, to address the problem of misdetection caused by regional overlapping between some tightly distributed OBIs, the character regions are simultaneously represented by multiscale Gaussian kernels to obtain regions with sharp edges. Besides, based on the kernel predictions of different scales, a novel post-processing pipeline is used to obtain accurate predictions of bounding boxes. Experiments show that our OBIs detector has achieved significant results on the OBIs dataset, which greatly outperforms several mainstream object detectors in both speed and efficiency. Dataset is available at http://jgw.aynu.edu.cn.展开更多
This article verified that the Tu state mentioned in the oracle inscriptions was the Xia people after the Xia Dynasty had been conquered by Tang, the first king of the Shang Dynasty m c.a. 16th century B.C. The state...This article verified that the Tu state mentioned in the oracle inscriptions was the Xia people after the Xia Dynasty had been conquered by Tang, the first king of the Shang Dynasty m c.a. 16th century B.C. The state of Xia, which originated from Yu, was entitled "Xia Hou"; its king was hence called "Xia Hou Di" (Emperor of Xia Hou), e.g."Xia Hou Di Qi". The Xia people, together with the Yin (Shang) people, and the Zhou people, were the so-called "people of San Dai" (Three Dynasties). As mentioned in "Lunyu, Bayi", they founded the states, with the Xia people being associated with the pine, the Yin people with the cypress, and the Zhou people with the chestnut.展开更多
The 12 animal calendars of the Chinese zodiac are the essence and source of Chinese civilization,and have been deeply rooted in the production,life,and social activities of various ethnic groups in China since ancient...The 12 animal calendars of the Chinese zodiac are the essence and source of Chinese civilization,and have been deeply rooted in the production,life,and social activities of various ethnic groups in China since ancient times.The ancient Luo Yue stone inscription1 is a popular ancient script from four to six thousand years ago,and 17,496 characters have been found,which is the earliest script found on the Chinese land so far.A comparative study of Chinese zodiac characters2 between the ancient Luo Yue stone inscriptions and the oracle bone through paleographic conformation reveals that the two characters have the same and similar characteristics.Therefore,this paper intends to further investigate the kinship between the two,and to conduct a preliminary exploration of the origin,development,and evolution of the zodiac by combining recent human archaeological data,emerging molecular anthropological data,historical literature,and data from the Chinese Civilization Exploration Project,in an attempt to show the integration and dependence of Chinese civilization,the pluralistic pattern of Chinese culture,and the Chinese nation for thousands of years.展开更多
We are very glad to welcome honored guests from afar, and with them we makefriends in a bid to expand the magnitude of opening-up toward the prosperity ofZhejiang-Wan Xueyuan, January 1995.
基金We are grateful for financial supports from National Natural Science Foundation of China(NSFC)(Grants No.61575097 and 11704201)National Natural Science Foundation of Tianjin City(NSFTJ)(17JCQNJC01600 and 19JCZDJC32700)the Fundamental Research Funds for the Central Universities.
文摘We report on the fabrication of circular cladding waveguides with cross-section diameters of 60−120μm in Pr:YAG crystal by applying femtosecond laser inscription.The fabricated waveguides present 2D guidance on the cross-section and fairly low propagation losses.Multiple high-order guiding modes are observed in waveguides with different diameters.Corresponding simulation results reveal the origin of a specific kind of guiding modes.Confocal micro-Raman(μ-Raman)experiments demonstrate the modification effects in femtosecond laser affected areas and ascertain the refractive index induced guiding mechanism.In addition,luminescence emission properties of Pr3+ions at waveguide volume are well preserved during the femtosecond laser inscription process,which may result in a potential high-power visible waveguide laser.
基金This research has received funding from the European Research Council(ERC)under the European Union’s Horizon 2020 research and innovation program(Grant Agreement No.724480).
文摘Ultrafast laser inscription(ULI)inside semiconductors offers new perspectives for 3D monolithic structures to be fabricated and new functionalities to be added in electronic and photonic microdevices.However,important challenges remain because of nonlinear effects such as strong plasma generation that distort the energy delivery at the focal point when exposing these materials to intense infrared light.Up to now,the successful technological demonstrations have primarily concentrated on silicon(Si).In this paper,we target at another important semiconductor:gallium arsenide(GaAs).With nonlinearities higher than those of Si,3D-machining of GaAs with femtosecond pulses becomes even harder.However,we show that the difficulty can be circumvented by burst-mode irradiation.We generate and apply trains of pulses at terahertz repetition rates for efficient pulse-to-pulse accumulation of laser-induced free carriers in the focal region,while avoiding an overdose of prefocal excitations.The superior performance of burst-mode irradiation is confirmed by a comparative study conducted with infrared luminescence microscopy.The results indicate a successful reduction of the plasma density in the prefocal region so that higher pulse energy reaches the focal spot.The same method is applied to identify optimum irradiation conditions considering particular cases such as asymmetric pulse trains and aberrated beams.With 64-pulse trains,we successfully manage to cross the writing threshold providing a solution for ULI inside GaAs.The application potential is finally illustrated with a stealth dicing demonstration by taking benefit of the burst mode.The irradiation method opens wide possibilities for 3D structuring inside GaAs by ULI.
文摘A teaching model based on constructivism is proposed in this paper. The model contains five teaching steps, e.g. interpretation teaching, questioning- dialogue, knowledge and skills teaching, discussion- collaboration and field training. Practice proves that it can effectively improve the training efficiency of the training of English guides of stone inscription relics and enhance their interpretation quality and English skills.
基金the National Natural Science Foundation of China (No. U1504612, 61806007, U1804153)the National Language Committee scientific research projects of China (No. YWZ-J023, YB135-50)+1 种基金the Development Projects of Henan Province Science and Technology (No. 182102310039)the Science and Technology Key Project of Henan Province Education Department (No. 17A520002).
文摘Oracle bone inscriptions (OBI) has important historical and cultural values. The traditional OBI research methods are at a choke point, and the research method using computer science and information technology has opened up the way of OBI information processing. However, it faces some problems, such as large but not centralized knowledge system, long learning cycle, learning difficulties, being difficult to obtain resources, inconsistent format, low retrieval accuracy, and low knowledge sharing and reuse. To solve these problems, it designs an OBI big data research resource management and intelligent knowledge service platform. Its goal is to make full use of OBI big data characteristics and use the knowledge engineering technology to build an OBI knowledge ecosystem. The experiment results show that the platform proposed provides effective one-stop knowledge management and knowledge service.
文摘The detection of Oracle Bone Inscriptions (OBIs) is one of the most fundamental tasks in the study of Oracle Bone, which aims to locate the positions of OBIs on rubbing images. The existing methods are based on the scheme of anchor boxes, involving complex network design and a great number of anchor boxes. In order to overcome the problem, this paper proposes a simpler but more effective OBIs detector by using an anchor-free scheme, where shape-adaptive Gaussian kernels are employed to represent the spatial regions of different OBIs. More specifically, to address the problem of misdetection caused by regional overlapping between some tightly distributed OBIs, the character regions are simultaneously represented by multiscale Gaussian kernels to obtain regions with sharp edges. Besides, based on the kernel predictions of different scales, a novel post-processing pipeline is used to obtain accurate predictions of bounding boxes. Experiments show that our OBIs detector has achieved significant results on the OBIs dataset, which greatly outperforms several mainstream object detectors in both speed and efficiency. Dataset is available at http://jgw.aynu.edu.cn.
文摘This article verified that the Tu state mentioned in the oracle inscriptions was the Xia people after the Xia Dynasty had been conquered by Tang, the first king of the Shang Dynasty m c.a. 16th century B.C. The state of Xia, which originated from Yu, was entitled "Xia Hou"; its king was hence called "Xia Hou Di" (Emperor of Xia Hou), e.g."Xia Hou Di Qi". The Xia people, together with the Yin (Shang) people, and the Zhou people, were the so-called "people of San Dai" (Three Dynasties). As mentioned in "Lunyu, Bayi", they founded the states, with the Xia people being associated with the pine, the Yin people with the cypress, and the Zhou people with the chestnut.
文摘The 12 animal calendars of the Chinese zodiac are the essence and source of Chinese civilization,and have been deeply rooted in the production,life,and social activities of various ethnic groups in China since ancient times.The ancient Luo Yue stone inscription1 is a popular ancient script from four to six thousand years ago,and 17,496 characters have been found,which is the earliest script found on the Chinese land so far.A comparative study of Chinese zodiac characters2 between the ancient Luo Yue stone inscriptions and the oracle bone through paleographic conformation reveals that the two characters have the same and similar characteristics.Therefore,this paper intends to further investigate the kinship between the two,and to conduct a preliminary exploration of the origin,development,and evolution of the zodiac by combining recent human archaeological data,emerging molecular anthropological data,historical literature,and data from the Chinese Civilization Exploration Project,in an attempt to show the integration and dependence of Chinese civilization,the pluralistic pattern of Chinese culture,and the Chinese nation for thousands of years.
文摘We are very glad to welcome honored guests from afar, and with them we makefriends in a bid to expand the magnitude of opening-up toward the prosperity ofZhejiang-Wan Xueyuan, January 1995.
