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FAST Observations of Four Comets to Search for the Molecular Line Emissions between 1.0 and 1.5 GHz Frequencies
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作者 Long-Fei Chen Chao-Wei Tsai +11 位作者 Jian-Yang Li Bin Yang Di Li Yan Duan Chih-Hao Hsia Zhichen Pan Lei Qian Donghui Quan Xue-Jian Jiang Xiaohu Li Ruining Zhao Pei Zuo 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第10期130-140,共11页
We used the Five-hundred-meter Aperture Spherical radio Telescope(FAST)to search for the molecular emissions in the L-band between 1.0 and 1.5 GHz toward four comets,C/2020 F3(NEOWISE),C/2020 R4(ATLAS),C/2021 A1(Leona... We used the Five-hundred-meter Aperture Spherical radio Telescope(FAST)to search for the molecular emissions in the L-band between 1.0 and 1.5 GHz toward four comets,C/2020 F3(NEOWISE),C/2020 R4(ATLAS),C/2021 A1(Leonard),and 67P/Churyumov-Gerasimenko during or after their perihelion passages.Thousands of molecular transition lines fall in this low-frequency range,many attributed to complex organic or prebiotic molecules.We conducted a blind search for the possible molecular lines in this frequency range in those comets and could not identify clear signals of molecular emissions in the data.Although several molecules have been detected at high frequencies of greater than100 GHz in comets,our results confirm that it is challenging to detect molecular transitions in the L-band frequency ranges.The non-detection of L-band molecular lines in the cometary environment could rule out the possibility of unusually strong lines,which could be caused by the masers or non-LTE effects.Although the line strengths are predicted to be weak,for FAST,using the ultra-wide bandwidth receiver and improving the radio frequency interference environments would enhance the detectability of those molecular transitions at low frequencies in the future. 展开更多
关键词 ASTROCHEMISTRY ISM:molecules comets:general line:identification
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Co-variability Between the Broad Absorption Lines and Narrow Absorption Lines
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作者 Bo-Lin Qin Jing Li Wei-Jian Lu 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第9期99-105,共7页
We investigate the relationship between the variability of broad absorption lines(BALs)or narrow absorption lines(NALs)and that of continuum using a data set of two-epoch SDSS spectra containing 134 C IV NAL-BAL pairs... We investigate the relationship between the variability of broad absorption lines(BALs)or narrow absorption lines(NALs)and that of continuum using a data set of two-epoch SDSS spectra containing 134 C IV NAL-BAL pairs.Our analysis reveals an anti-correlation between the fractional equivalent width(EW)variations in NALs(or BALs)and the fractional flux variations of the continuum,with Spearman rank correlation coefficients of r=-0.47(p=1E-08)and r=-0.58(p=1E-13),respectively.In addition,we find a positive correlation between the fractional EW variations in NALs and BALs(r=0.72,p=1E-22),and derive a regression equation ΔEW_(NAL)/<EW_(NAL)>=0.803ΔEW_(BAL)/<EW_(BAL)>+0.008,with an intrinsic scatter of 0.14.These results suggest that the variability in the ionizing continuum may play a significant role in the observed changes in C IV NALs and BALs,supporting the idea of photoionization-driven variability.The co-variability between C IV NALs and BALs may imply that they originate from outflows with similar physical conditions. 展开更多
关键词 (galaxies:)quasars:absorption lines (galaxies:)quasars:general galaxies:active
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General Entropy Model of Line Segments Uncertainty in GIS
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作者 SHI Yufeng SHI Wenzhong 《Geo-Spatial Information Science》 2007年第1期61-66,共6页
Spatial data uncertainty can directly affect the quality of digital products and GIS-based decision making. On the basis of the characteristics of randomicity of positional data and fuzziness of attribute data, taking... Spatial data uncertainty can directly affect the quality of digital products and GIS-based decision making. On the basis of the characteristics of randomicity of positional data and fuzziness of attribute data, taking entropy as a measure, the stochastic entropy model of positional data uncertainty and fuzzy entropy model of attribute data uncertainty are proposed. As both randomic-ity and fuzziness usually simultaneously exist in linear segments, their omnibus effects are also investigated and quantified. A novel uncertainty measure, general entropy, is presented. The general entropy can be used as a uniform measure to quantify the total un-certainty caused by stochastic uncertainty and fuzzy uncertainty in GIS. 展开更多
关键词 UNCERTAINTY line segment general entropy stochastic entropy fuzzy entropy uniform measure
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Research of Dynamic Material Handling in an Automobile General Assembly Line Based on Real-time Information
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作者 WANG Nan LI Shi-qi WANG Jun-feng ZHANG Zhen-li 《International Journal of Plant Engineering and Management》 2012年第1期34-43,共10页
The status of material delivery of an automobile general assembly line is analyzed, and the technique to achieve the real-time tracking of assembly status information is proposed based on RFID( Radio Frequency Identi... The status of material delivery of an automobile general assembly line is analyzed, and the technique to achieve the real-time tracking of assembly status information is proposed based on RFID( Radio Frequency Identification). Thus the consumption of line-side buffer is obtained dynamically, then the type and quantity of needed material are fed back to the subsystem of material handling; the algorithm for determining the best time departure time of delivery driver based on minimizing of total time penalty function is proposed. This approach makes the material amount of a single delivery trip maximized and improves the efficiency of delivery drivers significantly in the case of does not affect the assembly line normal throughput. Additionally, although this dynamic material handling method is developed for the automobile assembly plant, it should be pointed out that this method is also applicable to other mixed model assembly plants such as electronics, semiconductor and aerospace industry. 展开更多
关键词 automobile general assembly line material handling best departure time
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EXPERIMENTS ON THE GROUP GENERALIZATIONG OF CONTOUR LINES FOR TOPOGRAPHIC MAPS
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作者 FEI Lifan 《Geo-Spatial Information Science》 1998年第1期85-95,共11页
This paper analyzes the advantages and disadvantages of two techni-cal lines for automatic group generalization of contour lines.The author suggeststhat it is possible to get faster and better generalization results i... This paper analyzes the advantages and disadvantages of two techni-cal lines for automatic group generalization of contour lines.The author suggeststhat it is possible to get faster and better generalization results if we simulate theintelligence of human experts in program designing,retrieve geomorphologicalstructural information using the input data of 2-D contour lines and derive andoutput the generalied 2-D results directly. 展开更多
关键词 CONTOUR lineS automatic group generalIZATION artificial .intelli-gence
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A Progressive Line Simplification Algorithm 被引量:2
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作者 Christoph Brandenberger Lorenz Hurni 《Geo-Spatial Information Science》 2002年第3期41-45,75,共6页
An application of line simplification considering spatial knowledge is described.A method for identifying potential conflict regions,in order to avoid the self_intersection of generalized lines,is also discussed.Furth... An application of line simplification considering spatial knowledge is described.A method for identifying potential conflict regions,in order to avoid the self_intersection of generalized lines,is also discussed.Furthermore,a new progressive line simplification algorithm is presented.From the view point of spatial cognition,a spatial hierarchical structure is proposed,and its application to construction of spatial knowledge related to a line is explained. 展开更多
关键词 PROGRESSIVE line SIMPLIFICATION map generalIZATION SPATIAL knowledge SPATIAL cognitive SPATIAL hierarchical structure potential CONFLICT region selfintersection of a line
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Biplot Analysis of Genotype by Environment for Cooking Quality in Hybrid Rice: A Tool for Line × Tester Data 被引量:1
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作者 Mohammad H. FOTOKIAN Kayvan AGAHI 《Rice science》 SCIE 2014年第5期282-287,共6页
A study of combining ability for improving rice cooking quality was carried out via genotype plus genotype x environment (GGE) biplot. Four restorer lines and three male sterile lines were used to obtain F1 in a lin... A study of combining ability for improving rice cooking quality was carried out via genotype plus genotype x environment (GGE) biplot. Four restorer lines and three male sterile lines were used to obtain F1 in a line x tester trial at the Rice Research Institute, Amol, Iran in 2009. GGE biplot analysis showed that Neda and IR56 were the best general combiners for amylose content (AC), whereas Nemat and IR28 had the highest general combining ability (GCA) effects for gelatinization temperature (GT), and IR58 and IR59 showed the highest GCA effects in terms of gel consistency (GC). Meanwhile IR58 and IR59 showed large specific combining ability (SCA) effects for AC, while Neda and SA13 had high SCA effects for GT. Nemat and IR28 had large SCA effects for GC. Because intermediate levels ofAC, GT and GC are ideal, Nemat × IR59 was considered as the best possible cross. Based on these results, the GGE biplot showed good potential for identifying suitable parents, heterotic crosses and the best hybrids in line x tester data. 展开更多
关键词 line x tester trial general combining ability specific combining ability hybrid rice genotype plus genotype x environment biplot
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On the emission lines in active galactic nuclei with relativistic jets 被引量:1
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作者 Luigi Foschini 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2012年第4期359-368,共10页
The effect of the observed continuum emitted from a relativistic jet on the measurement of the full width at half maximum (FWHM) of an emission line is analyzed. If the jet contribution is not properly subtracted, t... The effect of the observed continuum emitted from a relativistic jet on the measurement of the full width at half maximum (FWHM) of an emission line is analyzed. If the jet contribution is not properly subtracted, the FWHM of the line could seem narrower than it should. The cases of an emission line detected in BL Lac objects and γ-ray Narrow-Line Seyfert 1 galaxies (γ-NLS1s) are addressed. It is shown that the smallness of the observed FWHM of the Lyα lines detected in three well-known BL Lacs is an effect due to the combined action of both the relativistic jet and a weak accretion disk. Once the Doppler boosting effect of the jet continuum is removed, the intrinsic FWHM values of the lines are found to be in the usual range. By contrast, the narrow permitted lines in γ-NLS1s are really narrow, since the disk and the lines are much more powerful. This also confirms that γ-NLS1 is really a new class of γ-ray emitting AGN, different from blazars and radio galaxies. 展开更多
关键词 line profiles—galaxies: jets—BL Lacertae Objects: general—galaxies: Seyfert
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The Spatial Characteristics of a Line and Their Application to Line Simplification
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作者 GUOQingsheng ChristophBrandenberger 《Geo-Spatial Information Science》 2002年第1期62-67,共6页
This paper discusses the spatial knowledge related to a line ,and the characteristic points of lines is detected.According to the requirements of line generalization,new algorithms for identifying characteristic line ... This paper discusses the spatial knowledge related to a line ,and the characteristic points of lines is detected.According to the requirements of line generalization,new algorithms for identifying characteristic line points are presented.These characteristic points are used to improve the algorithms of line generalization.An algorithm for identifying bends is shown.In this paper,improved algorithms based on those by Douglas_Peucker,Visvalingam and Whyatt are shown.In this test,the progressive process of line generalization is emphasized. 展开更多
关键词 spatial knowledge characteristic point BEND automated map generalization line simplification progressive map generalization
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The Mg_(Ⅱ)absorption line systems in quasar spectra from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope
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作者 Zhi-Fu Chen Huan-Chang Qin +3 位作者 Yan-Chun Gao Run-Jin Gui Zhe-Geng Chen Ting-Ting Pang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2021年第4期119-128,共10页
Making use of quasar spectra from LAMOST,in the spectral data around the Mg_(Ⅱ)emission lines,research described in this paper has detected 217 Mg_(Ⅱ)narrow absorption lines(NALs)with W_(r)^(λ2796)≥3σ_(w)and W_(r... Making use of quasar spectra from LAMOST,in the spectral data around the Mg_(Ⅱ)emission lines,research described in this paper has detected 217 Mg_(Ⅱ)narrow absorption lines(NALs)with W_(r)^(λ2796)≥3σ_(w)and W_(r)^(λ2803)≥2σ_(w)in a redshift range of 0.4554≤z_(abs)≤2.1110.For quasars observed by both LAMOST and SDSS,we find that 135 Mg_(Ⅱ)NALs were obviously observed in the LAMOST spectra,347 Mg_(Ⅱ)NALs were were apparent in the SDSS spectra,and 132 Mg_(Ⅱ)NALs were clearly present in both the SDSS and LAMOST spectra.The missed Mg_(Ⅱ)NALs are likely ascribed to low signal-to-noise ratios of corresponding spectra.Among the Mg 11 NALs obviously observed in SDSS or LAMOST spectra,eight Mg 11 NALs were significantly changed with|ΔW_(r)^(λ2796)|≥3σw in time intervals ofΔMJD/(1+z_(em))=359-2819 d. 展开更多
关键词 line:identification quasars:absorption lines quasars:general
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Results of Selection Studies of Alfalfa Based on Inbred Lines
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作者 Meirman Galiolla Kenenbayev Serik +2 位作者 Yerzhanova Sakysh Abayev Serik Toktarbekova Saltanat 《Journal of Agricultural Science and Technology(A)》 2017年第5期309-316,共8页
The collection of alfalfa in the context of ecology-geographical groups was studied, consisting of 1,078 samples, including 985 samples of the cultivated species--M, sativa L. and M. varia Mart., and 93 samples for ot... The collection of alfalfa in the context of ecology-geographical groups was studied, consisting of 1,078 samples, including 985 samples of the cultivated species--M, sativa L. and M. varia Mart., and 93 samples for other wild species. Highly productive samples are allocated in the three-year cycle of using the grass stand in the haymaking regime. Individual genotypes of isolated samples are used for selection of inbred lines required for the formation of synthetic varieties. Inbred lines were created by forced self-pollination on genotypes with signs of self-fertility. Methodical experiments established the efficiency of bringing inbred lines to generations J2 and J3. In this case, the overall combinational ability reaches a potential value, and further incubation outside of J2 and J3 does not significantly affect its value. With the selection of the best inbred lines in J2 and J3, the lucerne varieties: Kokorai, Osimtal and Kokbalausa, which are protected by patents and author's certificates, have been created in accordance with the general combination ability and their inclusion in the structure of synthetic varieties. 展开更多
关键词 Inbred lines general combination ability (GCA) synthetic grade yield of green mass.
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X-ray Emission Lines in GRB Afterglows: Evidence for a Two-component Jet Model
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作者 Wei-Hong Gao Da-Ming Wei 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2005年第6期571-578,共8页
X-ray emission lines have been observed in X-ray afterglows of several T-ray bursts (GRBs). It is a major breakthrough for understanding the nature of the progenitors. It has been proposed that the X-ray emission li... X-ray emission lines have been observed in X-ray afterglows of several T-ray bursts (GRBs). It is a major breakthrough for understanding the nature of the progenitors. It has been proposed that the X-ray emission lines can be well explained by the Geometry-Dominated models, but in these models the illuminat- ing angle is much larger than that of the collimated jet of the GRB. For GRB 011211, we have obtained an illuminating angle of about 0 - 45°, while the angle of the GRB jet is only 3.6°. So we propose that the outflow of GRBs with emission lines should have two distinct components: a wide component that illuminates the reprocessing material and produces the emission lines and a narrow one that produces the GRB. Observations show the energy for producing the emission lines is higher than that of the GRB. In this case, when the wide component dominates the afterglows, a bump should appear in the GRB afterglow. For GRB 011211, the bump should occur within 0.05 days of the GRB, which is obviously too early for the observation to catch it. Alongside the X-ray emission lines there should also be a bright emission component between the UV and the soft X-rays. These features can be tested by the Swift satellite in the near future. 展开更多
关键词 gamma rays: bursts -- line profiles -- ISM: jets and outflows -- supernovae: general
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Properties of the Narrow Line Seyfert 1 Galaxies Revisited
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作者 Xiang Liu Pingping Yang +1 位作者 Renzhi Supriyanto Zhengying Zhang 《International Journal of Astronomy and Astrophysics》 2016年第2期166-174,共9页
There is growing evidence to suggest that the black hole mass has been previously underestimated with the Hb line width for certain Active Galactic Nuclei (AGN). With the assumption of the flatter rather than isotropi... There is growing evidence to suggest that the black hole mass has been previously underestimated with the Hb line width for certain Active Galactic Nuclei (AGN). With the assumption of the flatter rather than isotropic velocity distribution of gases in the broad-line region of AGN, we investigated the properties of Narrow Line Seyfert 1 (NLS1) galaxies, like the black hole mass and the Eddington ratio, and compared with Broad Line Seyfert 1 (BLS1) galaxies. Since gamma-rays detected in a few NLS1s which favored a smaller viewing angle in NLS1s than BLS1s, with the projection effect, we estimated the relative black hole mass and Eddington ratio for NLS1s and BLS1s. The result implies that the NLS1s and BLS1s have similar black hole masses and Eddington ratios, peaked at a larger black hole mass and lower Eddington ratio for the NLS1s than thought before. Furthermore, with applying the correction factor 6 of average black hole mass as derived from the modeling of both optical and UV data in radio-loud NLS1s by Calderone et al., to the Xu et al. sample, we find that the NLS1s and BLS1s also show similar black hole masses and Eddington ratios, peaked at 2.0 × 107 solar masses and 0.12 (Eddington ratio) for the NLS1s. The   relation due to the enhanced black hole masses of NLS1s is discussed. In addition, there seems to show a linear correlation between jet power and disk luminosity for the flat spectrum radio-loud NLS1 sample, which implies an accretion dominated rather than black hole spin dominated jet. 展开更多
关键词 Quasars: Emission lines Quasars: general Radio Continuum: Galaxies X-Rays: Galaxies
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Administration of fentanyl via a slow intravenous fluid line compared with rapid bolus alleviates fentanyl-induced cough during general anesthesia induction 被引量:7
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作者 Min-qiang LIU Feng-xian LI +4 位作者 Ya-kun HAN Jun-yong HE Hao-wen SHI Li LIU Ren-liang HE 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2017年第11期955-962,共8页
Objective: Fentanyl-induced cough (FIC) is a common complication with a reported incidence from 18.0% to 74.4% during general anesthesia induction. FIC increases the intrathoracic pressure and risks of postoper- at... Objective: Fentanyl-induced cough (FIC) is a common complication with a reported incidence from 18.0% to 74.4% during general anesthesia induction. FIC increases the intrathoracic pressure and risks of postoper- ative nausea and vomiting, yet available treatments are limited. This study was designed to investigate whether ad- ministering fentanyl via a slow intravenous fluid line can effectively alleviate FIC during induction of total intravenous general anesthesia. Methods: A total number of 1200 patients, aged 18-64 years, were enrolled, all of whom were American Society of Anesthesiologists (ASh,) grade I or II undergoing scheduled surgeries. All patients received total intravenous general anesthesia, which was induced sequentially by midazolam, fentanyl, propofol, and cisatracurium injection. Patients were randomly assigned to receive fentanyl 3.5 pg/kg via direct injection (control group) or via a slow intravenous fluid line. FIC incidence and the severity grades were analyzed with the Mann-Whitney test. Other adverse reactions, such as hypotension, hypertension, bradycardia, tachycardia, hypoxemia, vomiting, and aspiration, during induction were also observed. The online clinical registration number of this study was ChiCTR-IOR-16009025. Re- sults: Compared with the control group, the incidence of FIC was significantly lower in the slow intravenous fluid line group during induction (9.1%, 95% confidence interval (CI): 6.7%-11.4% vs. 55.9%, 95% CI: 51.8%-60.0%, P=0.000), as were the severity grades (P=0.000). There were no statistical differences between the two groups with regard to other adverse reactions (P〉0.05). Conclusions: The administration of fentanyl via a slow intravenous fluid line can alleviate FIC and its severity during induction for total intravenous general anesthesia. This method is simple, safe, and reliable, and deserves clinical expansion. 展开更多
关键词 general anesthesia Fentanyl-induced cough Slow intravenous fluid line Alleviate Induction
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AN SQP ALGORITHM WITH NONMONOTONE LINE SEARCHFOR GENERAL NONLINEAR CONSTRAINED OPTIMIZATION PROBLEM 被引量:3
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作者 He, GP Diao, BQ Gao, ZY 《Journal of Computational Mathematics》 SCIE CSCD 1997年第2期179-192,共14页
In this paper, an SQP type algorithm with a new nonmonotone line search technique for general constrained optimization problems is presented. The new algorithm does not have to solve the second order correction subpro... In this paper, an SQP type algorithm with a new nonmonotone line search technique for general constrained optimization problems is presented. The new algorithm does not have to solve the second order correction subproblems for each iterations, but still can circumvent the so-called Maratos effect. The algorithm's global convergence and superlinear convergent rate have been proved. In addition, we can prove that, after a few iterations, correction subproblems need not be solved, so computation amount of the algorithm will be decreased much more. Numerical experiments show that the new algorithm is effective. 展开更多
关键词 SQP SI AN SQP ALGORITHM WITH NONMONOTONE line SEARCHFOR general NONlineAR CONSTRAINED OPTIMIZATION PROBLEM MATH line
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A very bright (i=16.44) quasar in the ‘redshift desert’ discovered by the Guoshoujing Telescope (LAMOST) 被引量:2
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作者 Xue-Bing Wu Zhao-Yu Chen +18 位作者 Zhen-Dong Jia Wen-Wen Zuo Yong-Heng Zhao A-Li Luo Zhong-Rui Bai Jian-Jun Chen Hao-Tong Zhang Hong-Liang Yan Juan-Juan Ren Shi-Wei Sun Hong Wu Yong Zhang Ye-Ping Li Qi-Shuai Lu You Wang Ji-Jun Ni Hai Wang Xu Kong Shi-Yin Shen 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2010年第8期737-744,共8页
The redshift range from 2.2 to 3 is known as the 'redshift desert' of quasars because quasars with redshifts in this range have similar optical colors as normal stars and are thus difficult to find in optical sky su... The redshift range from 2.2 to 3 is known as the 'redshift desert' of quasars because quasars with redshifts in this range have similar optical colors as normal stars and are thus difficult to find in optical sky surveys. A quasar candidate, SDSS J085543.40-001517.7, which was selected by a recently proposed criterion involving near-IR Y - K and optical g - z colors, was identified spectroscopically as a new quasar with a redshift of 2.427 by the Guoshoujing Telescope (LAMOST) commissioning observation in 2009 December and confirmed by the observation made with the NAOC/Xinglong 2.16 m telescope in 2010 March. This quasar was not identified in the SDSS spectroscopic survey. Comparing with other SDSS quasars, we found that this new quasar, with an i magnitude of 16.44, is apparently the brightest one in the redshift range from 2.3 to 2.7. From its spectral properties, we derived its central black hole mass to be (1.4 - 3.9) × 10^110 M⊙ and its bolometric luminosity to be 3.7 × 10^48 erg s^-1, which indicates that this new quasar is intrinsically very bright and belongs to the class of the most luminous quasars in the universe. Our identification supports the notion that quasars in the redshift desert can be found by the quasar selection criterion involving the near-IR colors. More missing quasars are expected to be uncovered by future LAMOST spectroscopic surveys, which is important to the study of the cosmological evolution of quasars at redshifts higher than 2.2. 展开更多
关键词 QUASARS general -- quasars emission lines -- galaxies active
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Conversion of the Statistical Combining Ability into a Genetic Concept 被引量:5
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作者 LV Ai-zhi ZHANG Hao +3 位作者 ZHANG Zu-xin TAO Yong-sheng YUE Bing ZHENG Yong-lian 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2012年第1期43-52,共10页
Since the combining ability was proposed in 1942, efforts to uncover the genetic basis underlying this phenomenon have been ongoing for nearly 70 yr, with little success. Some breeding strategies based on evaluation o... Since the combining ability was proposed in 1942, efforts to uncover the genetic basis underlying this phenomenon have been ongoing for nearly 70 yr, with little success. Some breeding strategies based on evaluation of combining ability have been produced, and are still extensively used in hybrid breeding. In this review, the genetic basis underlying these breeding strategies is discussed, and a potential genetic control of general combining ability (GCA) is postulated. We suggested that GCA and the yields of inbred lines might be genetically controlled by different sets of loci on the maize genome that are transmitted into offspring. Different inbred lines might possess different favorable alleles for GCA. In hybrids, loci involved in multiple pathways, which are directly or indirectly associated with yield performance, might be regulated by GCA loci. In addition, a case of GCA mapping using a set of testcross progeny from introgression lines is provided. 展开更多
关键词 general combining ability (GCA) testcross GCA mapping quantitative trait locus (QTL) maize (Zea mays L.) introgression line
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A simulation package—SASAL for X-ray and EUV spectroscopy of astrophysical and laboratory plasmas 被引量:2
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作者 Gui-Yun Liang Fang Li +3 位作者 Fei-Lu Wang Yong Wu Jia-Yong Zhong Gang Zhao 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2014年第10期1351-1366,共16页
For the laboratory astrophysics community, those spectroscopic modeling codes extensively used in astronomy, e.g. Chianti, AtomDB, Cloudy and Xstar, cannot be directly applied to analyzing laboratory measurements due ... For the laboratory astrophysics community, those spectroscopic modeling codes extensively used in astronomy, e.g. Chianti, AtomDB, Cloudy and Xstar, cannot be directly applied to analyzing laboratory measurements due to their discrepancies from astrophysical cases. For example, plasma from an electron beam ion trap has an electron energy distribution that follows a Gaussian profile, instead of a Maxwellian one. The laboratory miniature for a compact object produced by a laser-driven implo- sion shows a departure from equilibrium, that often occurs in celestial objects, so we setup a spectral analysis system for astrophysical and laboratory (SASAL) plasmas to act as a bridge between them, which benefits the laboratory astrophysical community. 展开更多
关键词 atomic data -- line formation -- plasmas -- X-rays general
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Eight new quasars discovered by the Guoshoujing Telescope (LAMOST) in one extragalactic field 被引量:1
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作者 Xue-Bing Wu Zhen-Dong Jia +18 位作者 Zhao-Yu Chen Wen-Wen Zuo Yong-Heng Zhao A-li Luo Zhong-Rui Bai Jian-Jun Chen Hao-Tong Zhang Hong-Liang Yan Juan-Juan Ren Shi-Wei Sun Hong Wu Yong Zhang Ye-Ping Li Qi-Shuai Lu You Wang Ji-Jun Ni Hai Wang Xu Kong Shi-Yin Shen 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2010年第8期745-752,共8页
We report the discovery of eight new quasars in one extragalactic field (a five-degree field centered at RA=08^h58^m08.2^s, Dec=01°32′29.7″) with the Guoshoujing Telescope (LAMOST) commissioning observation... We report the discovery of eight new quasars in one extragalactic field (a five-degree field centered at RA=08^h58^m08.2^s, Dec=01°32′29.7″) with the Guoshoujing Telescope (LAMOST) commissioning observations made on 2009 December 18. These quasars, with i magnitudes from 16.44 to 19.34 and redshifts from 0.898 to 2.773, were not identified in the SDSS spectroscopic survey, though six of them with redshifts less than 2.5 were selected as quasar targets in SDSS. Except for one source without near-IR Y-band data, seven of these eight new quasars satisfy a newly proposed quasar selection criterion involving both near-IR and optical colors. Two of them were found in the 'redshift desert' for quasars (z from 2.2 to 3), indicating that the new criterion is efficient for uncovering missing quasars with similar optical colors to stars. Although LAMOST encountered some problems during the commissioning observations, we were still able to identify 38 other known SDSS quasars in this field, with i magnitudes from 16.24 to 19.10 and redshifts from 0.297 to 4.512. Our identifications imply that a substantial fraction of quasars may be miss- ing in previous quasar surveys. The implication of our results to the future LAMOST quasar survey is discussed. 展开更多
关键词 QUASARS general -- quasars emission lines -- galaxies active
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New background quasars in the vicinity of the Andromeda Galaxy discovered with the Guoshoujing Telescope (LAMOST) 被引量:1
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作者 Zhi-Ying Huo Xiao-Wei Liu +17 位作者 Hai-Bo Yuan Hui-Hua Zhang Yong-Heng Zhao Jian-Jun Chen Zhong-Rui Bai Hao-Tong Zhang Hua-Wei Zhang Ruben Garcia-Benito Mao-Sheng Xiang Hong-Liang Yan Juan-Juan Ren Shi-Wei Sun Yong Zhang Ye-Ping Li Qi-Shuai Lu You Wang Ji-Jun Ni Hai Wang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2010年第7期612-620,共9页
We present preliminary analyses of spectra of quasar candidates in two Guoshoujing Telescope (GSJT, formerly named the Large Sky Area Multi-Object Fiber Spectroscopic Telescope - LAMOST) test fields near M 31 where ... We present preliminary analyses of spectra of quasar candidates in two Guoshoujing Telescope (GSJT, formerly named the Large Sky Area Multi-Object Fiber Spectroscopic Telescope - LAMOST) test fields near M 31 where one is close to the optical center of the disk and the other is towards the northeastern outskirts of the halo, obtained during the early stage of the GSJT commissioning in the last season of 2009. Both fields contain background low-redshift quasar candidates selected from the SDSS photometry. In total, 14 new quasars with redshifts up to 2 and i magnitudes between 16.7 and 19.2, are discovered, including 7 within the 2.5° central region of M 31. We briefly discuss the potential applications of these newly discovered bright quasars. 展开更多
关键词 GALAXIES individual (M31) -- quasars general -- quasars emission lines
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