The Chinese Giant Solar Telescope(CGST)low-dispersion spectrograph requires a large field-of-view(FOV)and high spatial resolution,which can be addressed by a carefully designed image slicer system.Our proposed design ...The Chinese Giant Solar Telescope(CGST)low-dispersion spectrograph requires a large field-of-view(FOV)and high spatial resolution,which can be addressed by a carefully designed image slicer system.Our proposed design divides the rectangular 50″×20″FOV at the telescope focal plane into four 50″×5″subfields.Each subfield undergoes optical reconstruction using its independent collimator-camera system(F/36-F/25.79),achieving vertical alignment and focal reduction of subfields to form a pseudo-slit.Using tilt mirrors for scanning allows simultaneous acquisition of spectral data with both a large FOV and a high angular resolution of 0.05″.This resolves manufacturing challenges for an image slicer,avoiding the requirement for hundreds of elements,multi-angle configurations,and compact dimensions,and also provides effective technical support for engineering work on the CGST.展开更多
Astronomical spectroscopy is a critical tool in many advanced research topics such as cosmic origin,galaxy evolution,stellar formation,and exoplanet detection.Medium-to-large aperture optical telescopes equipped with ...Astronomical spectroscopy is a critical tool in many advanced research topics such as cosmic origin,galaxy evolution,stellar formation,and exoplanet detection.Medium-to-large aperture optical telescopes equipped with various spectrographs are suitable for many large programs.However,many small-aperture(30-80 cm)telescopes have the potential to perform quick and flexible observations in the astronomical field.Using current technology,most portable astronomical spectrographs can capture broadband spectra by rotating or changing the gratings to scan the spectrum at multiple exposures.This paper presents a portable broadband astronomical spectrograph(called ESPEC-2)that features an echelle grating as the main disperser and a group of collimating and imaging lenses to simplify the optical system.For 30-80 cm aperture telescopes,the lightweight prototype(~3.5 kg)enables spectral observation with a spectral resolution of R≥6200 over a wavelength range of 400-900 nm with a single exposure.Moreover,it can be directly mounted on the telescope’s focus or connected via optical fiber.Its portability and versatility make it suitable for use as a general-purpose spectrograph in other scientific experiments.The developed compact broadband spectrograph is expected to make significant contributions to scientific research,outreach,and education.展开更多
随着会话推荐的广泛应用,如何充分利用语义信息、建模用户跨会话兴趣以及抑制数据噪声成为提升推荐性能的关键。为此提出一种新颖的会话推荐增强框架LGSBR,通过整合大语言模型(large language model,LLM)的语义理解能力与图神经网络(gra...随着会话推荐的广泛应用,如何充分利用语义信息、建模用户跨会话兴趣以及抑制数据噪声成为提升推荐性能的关键。为此提出一种新颖的会话推荐增强框架LGSBR,通过整合大语言模型(large language model,LLM)的语义理解能力与图神经网络(graph neural network,GNN)的结构建模能力,实现语义增强与个性化推荐。具体而言,利用大语言模型及微调的语言模型生成项目补充文本嵌入和用户跨会话兴趣嵌入,通过软注意力机制融合文本与ID嵌入,生成语义丰富的项目表示;引入用户兴趣嵌入,结合对齐损失实现个性化推荐;最后通过两阶段权重学习过滤噪声项目,优化会话表示。实验结果表明,在Beauty数据集上,LGSBR的P@20达到21.38%,MRR@20达到6.76%,分别较SR-GNN基线提升23.3%和50.56%;在MovieLen-1M数据集上,P@20为25.86%,MRR@20为7.58%,分别提升12.63%和10.98%;研究验证了LGSBR在多种GNN模型上的通用性和有效性。展开更多
In view of the inconsistency of channel gains and a large amount of interference noise in Solar Broadband Radio Spectrometer(SBRS) observation data,they will seriously affect the analysis of SBRS data.In this paper,a ...In view of the inconsistency of channel gains and a large amount of interference noise in Solar Broadband Radio Spectrometer(SBRS) observation data,they will seriously affect the analysis of SBRS data.In this paper,a method of Radio Frequency Interference(RFI) detection and mitigation for SBRS observation data is reported.Firstly,the SBRS observation data are preprocessed,a part of the observation data was selected to calculate the mean and variance to achieve the normalization of the entire observation data,which can avoid the influence of strong noise on the normalization result.Furthermore,we proposed an adaptive threshold RFI detection method based on fusion wavelet transform reconstruction and an RFI elimination method based on neighborhood weighted filling.It is worth mentioning that to detect RFI interference signals of different magnitudes,we adopted an iterative approach to the RFI detection and mitigation process.Through qualitative analysis of real observation data and quantitative analysis of simulated data,it is shown that the method proposed in this paper can effectively eliminate RFI in SBRS observation data,and improve the quality of observation data for further scientific analysis.展开更多
We present our state-of-the-art version of a frequency comb for calibration of astronomical spectrographs. The mode spacing of the frequency comb can be designed to match the resolution of a spectrograph. Combined wit...We present our state-of-the-art version of a frequency comb for calibration of astronomical spectrographs. The mode spacing of the frequency comb can be designed to match the resolution of a spectrograph. Combined with its excellent accuracy and stability, the spectral coverage of more than 70% of the whole visible spectrum range makes the frequency comb an ideal calibration source. In addition, the new version introduces the automatic start-up function that brings convenience to the astronomers.展开更多
The study has assessed the denitrification performance of fermented and dark-fermented biosolids as external carbon sources using lab-scaled Sequencing Batch Reactors （SBRs）. This was done by adding fermented and da...The study has assessed the denitrification performance of fermented and dark-fermented biosolids as external carbon sources using lab-scaled Sequencing Batch Reactors （SBRs）. This was done by adding fermented and dark-fermented biosolids into anoxic zones of two SBRs, and then assessing the change of effluent characteristics comparing to before adding and to a third controlled reactor. The results showed that by adding 150-170 mg rbCOD/L of either of the selected fermented biosolids, almost complete denitrification could be reached for tested SBRs （reduced from initial -20 mg NO3/L to 〈 1 mg NO3/L）. Finally, the experiment also found that the impact of NI-I4 components of fermented and dark-fermented biosolids onto the final effluent were much lesser than expected, where only less than 2.5 mg NH4/L were detected in the effluent, much lower than the added 5.0-5.7 mg/L.展开更多
The aim of this study was to assess the impact of industrial-grade sucrose as external carbon source on post-anoxic denitrification. This was done through the use of lab-scaled Sequencing Batch Reactors （SBRs） model...The aim of this study was to assess the impact of industrial-grade sucrose as external carbon source on post-anoxic denitrification. This was done through the use of lab-scaled Sequencing Batch Reactors （SBRs） modelling after a standard post-anoxic Waste Water Treatment Plant （WWTP）. Each reactor holds an effective volume of approximately 4 L, with the decant volume of 2 L per cycle, a Hydraulic Retention Time （HRT） of 8 hours, Sludge Retention Time （SRT） of about 11.5 ± 0.5 days. The experiments showed that adding industrial-grade sucrose into the post-anoxic zone has a very significant improvement where the nitrate removal rate increased from 10% to 68%. The experiment also verifies that most of the Specific Denitrification Rate （SDNR） calculated from the lab-scaled SBRs lie within the range of earlier study （2.29-2.85 mgNO3/gMLVSS/h）, and verified the results of both this experiment and the SDNR batch tests in previous study.展开更多
基金supported by National Key Research and Development Programme‘Frontier Research on Large Scientific Devices’Key Special Project(2024YFA1612000)Sino-German Science Foundation Program(M-0086)Yunnan Science and Technology Leading Talent Program(202105AB160001).
文摘The Chinese Giant Solar Telescope(CGST)low-dispersion spectrograph requires a large field-of-view(FOV)and high spatial resolution,which can be addressed by a carefully designed image slicer system.Our proposed design divides the rectangular 50″×20″FOV at the telescope focal plane into four 50″×5″subfields.Each subfield undergoes optical reconstruction using its independent collimator-camera system(F/36-F/25.79),achieving vertical alignment and focal reduction of subfields to form a pseudo-slit.Using tilt mirrors for scanning allows simultaneous acquisition of spectral data with both a large FOV and a high angular resolution of 0.05″.This resolves manufacturing challenges for an image slicer,avoiding the requirement for hundreds of elements,multi-angle configurations,and compact dimensions,and also provides effective technical support for engineering work on the CGST.
基金supported by the National Key R&D Program of China(2023YFF0714800)the Scientific Instrument Developing Project of the Chinese Academy of Sciences(ZDKYYQ20220009).
文摘Astronomical spectroscopy is a critical tool in many advanced research topics such as cosmic origin,galaxy evolution,stellar formation,and exoplanet detection.Medium-to-large aperture optical telescopes equipped with various spectrographs are suitable for many large programs.However,many small-aperture(30-80 cm)telescopes have the potential to perform quick and flexible observations in the astronomical field.Using current technology,most portable astronomical spectrographs can capture broadband spectra by rotating or changing the gratings to scan the spectrum at multiple exposures.This paper presents a portable broadband astronomical spectrograph(called ESPEC-2)that features an echelle grating as the main disperser and a group of collimating and imaging lenses to simplify the optical system.For 30-80 cm aperture telescopes,the lightweight prototype(~3.5 kg)enables spectral observation with a spectral resolution of R≥6200 over a wavelength range of 400-900 nm with a single exposure.Moreover,it can be directly mounted on the telescope’s focus or connected via optical fiber.Its portability and versatility make it suitable for use as a general-purpose spectrograph in other scientific experiments.The developed compact broadband spectrograph is expected to make significant contributions to scientific research,outreach,and education.
文摘随着会话推荐的广泛应用,如何充分利用语义信息、建模用户跨会话兴趣以及抑制数据噪声成为提升推荐性能的关键。为此提出一种新颖的会话推荐增强框架LGSBR,通过整合大语言模型(large language model,LLM)的语义理解能力与图神经网络(graph neural network,GNN)的结构建模能力,实现语义增强与个性化推荐。具体而言,利用大语言模型及微调的语言模型生成项目补充文本嵌入和用户跨会话兴趣嵌入,通过软注意力机制融合文本与ID嵌入,生成语义丰富的项目表示;引入用户兴趣嵌入,结合对齐损失实现个性化推荐;最后通过两阶段权重学习过滤噪声项目,优化会话表示。实验结果表明,在Beauty数据集上,LGSBR的P@20达到21.38%,MRR@20达到6.76%,分别较SR-GNN基线提升23.3%和50.56%;在MovieLen-1M数据集上,P@20为25.86%,MRR@20为7.58%,分别提升12.63%和10.98%;研究验证了LGSBR在多种GNN模型上的通用性和有效性。
基金funded by the Open Research Program of CAS Key Laboratory of Solar Activity,National Astronomical Observatories (KLSA201909)the National Natural Science Foundation of China (Nos.11773072 and 11873027)Yunnan Fundamental Research Projects (202001AT070135)。
文摘In view of the inconsistency of channel gains and a large amount of interference noise in Solar Broadband Radio Spectrometer(SBRS) observation data,they will seriously affect the analysis of SBRS data.In this paper,a method of Radio Frequency Interference(RFI) detection and mitigation for SBRS observation data is reported.Firstly,the SBRS observation data are preprocessed,a part of the observation data was selected to calculate the mean and variance to achieve the normalization of the entire observation data,which can avoid the influence of strong noise on the normalization result.Furthermore,we proposed an adaptive threshold RFI detection method based on fusion wavelet transform reconstruction and an RFI elimination method based on neighborhood weighted filling.It is worth mentioning that to detect RFI interference signals of different magnitudes,we adopted an iterative approach to the RFI detection and mitigation process.Through qualitative analysis of real observation data and quantitative analysis of simulated data,it is shown that the method proposed in this paper can effectively eliminate RFI in SBRS observation data,and improve the quality of observation data for further scientific analysis.
文摘We present our state-of-the-art version of a frequency comb for calibration of astronomical spectrographs. The mode spacing of the frequency comb can be designed to match the resolution of a spectrograph. Combined with its excellent accuracy and stability, the spectral coverage of more than 70% of the whole visible spectrum range makes the frequency comb an ideal calibration source. In addition, the new version introduces the automatic start-up function that brings convenience to the astronomers.
文摘The study has assessed the denitrification performance of fermented and dark-fermented biosolids as external carbon sources using lab-scaled Sequencing Batch Reactors （SBRs）. This was done by adding fermented and dark-fermented biosolids into anoxic zones of two SBRs, and then assessing the change of effluent characteristics comparing to before adding and to a third controlled reactor. The results showed that by adding 150-170 mg rbCOD/L of either of the selected fermented biosolids, almost complete denitrification could be reached for tested SBRs （reduced from initial -20 mg NO3/L to 〈 1 mg NO3/L）. Finally, the experiment also found that the impact of NI-I4 components of fermented and dark-fermented biosolids onto the final effluent were much lesser than expected, where only less than 2.5 mg NH4/L were detected in the effluent, much lower than the added 5.0-5.7 mg/L.
文摘The aim of this study was to assess the impact of industrial-grade sucrose as external carbon source on post-anoxic denitrification. This was done through the use of lab-scaled Sequencing Batch Reactors （SBRs） modelling after a standard post-anoxic Waste Water Treatment Plant （WWTP）. Each reactor holds an effective volume of approximately 4 L, with the decant volume of 2 L per cycle, a Hydraulic Retention Time （HRT） of 8 hours, Sludge Retention Time （SRT） of about 11.5 ± 0.5 days. The experiments showed that adding industrial-grade sucrose into the post-anoxic zone has a very significant improvement where the nitrate removal rate increased from 10% to 68%. The experiment also verifies that most of the Specific Denitrification Rate （SDNR） calculated from the lab-scaled SBRs lie within the range of earlier study （2.29-2.85 mgNO3/gMLVSS/h）, and verified the results of both this experiment and the SDNR batch tests in previous study.
