Jing Li

National Space Science, Peping, Beijing, China

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Publications (44)66.53 Total impact

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    ABSTRACT: Terahertz (THz) frequency region, defined from 0.1 to 10 THz, is an important frequency band for radio astronomy and atmospheric science. As NbN Superconductor-Insulator-Superconductor (SIS) mixers used for terahertz detection, which are studied by the Purple Mountain Observatory (PMO), Chinese Academy of Sciences (CAS), work at 8–10 K, and require condition of micro vibrations, its astronomical observation in aerospace is limited by suitable refrigeration method. 4 K high frequency pulse tube cryocooler developed by Key Laboratory of Space Energy Conversion Technologies (SECT), Technical Institute of Physics and Chemistry (TIPC), CAS, offers an opportunity for the application of SIS mixers. This article introduces the progress of the two-stage high frequency pulse tube cryocooler researched by TIPC. The cryocooler has reached a no load temperature of 4.5 K which is the lowest temperature for this kind of cryocooler reported so far. The successful coupling between the THz component and the high frequency pulse tube cryocooler lays a solid foundation for space detection in the terahertz band.
    Chinese Science Bulletin 09/2014; 59(27). DOI:10.1007/s11434-014-0457-5 · 1.37 Impact Factor
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    ABSTRACT: Niobium nitride (NbN) superconducting tunnel junctions (STJs) have an energy gap nearly double that of niobium STJs, making them potential sensitive detectors that operate at higher frequencies and temperatures. In this paper, we investigate the direct-detection behavior (i.e. the spectral response, current responsivity, noise characteristics, and noise equivalent power (NEP)) of a 500 GHz NbN STJ detector at temperatures from approximately 5 to 9 K. The detector shows an uncorrected NEP of 3.8 × 10−13 W/around 5 K and 1.5 × 10−12 W/at 9 K. Its performance can be further improved by adopting a cryogenically cooled readout circuit and fabricating the device with a wiring layer of higher critical-transition temperatures.
    Superconductor Science and Technology 05/2014; 27(7):075003. DOI:10.1088/0953-2048/27/7/075003 · 2.80 Impact Factor
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    ABSTRACT: In this paper, we will introduce a dual-THz-band SIS (Superconductor-Insulator-Superconductor) heterodyne radiometer system developed for the atmospheric profiling synthetic observation system project (APSOS). This THz system is intended to have a durable and compact design to meet the challenging requirements of remote operation. The system as well as its major components such as antenna tipping, quasi-optics, cryogenics, SIS mixers and FFTS backend will be discussed thoroughly. Some scientific simulation focusing on the atmospheric profiling components at THz bands will also be investigated.
    Proceedings of SPIE - The International Society for Optical Engineering 12/2012; DOI:10.1117/12.999736 · 0.20 Impact Factor
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    ABSTRACT: Terahertz Superconducting Imaging Array (TeSIA) is a project for the development of a large THz direct-detection array for mapping observations. The prototype of TeSIA is an 8×8 pixel direct-detection array operating at the 850 μm band, incorporating THz superconducting detectors such as kinetic inductance detectors (KIDs) and transition edge sensors (TES). KIDs have the advantage that only a broadband low noise cryogenic amplifier is needed at low temperature for the readout system, and hundreds of pixels could be readout simultaneously by the frequency-division multiplexing (FDM) technique. The readout system for a KIDs array is composed of several parts like excitation signal generating, intermediate frequency (IF) circuit, baseband signal acquisition and processing. Excitation signal is a kind of comb signal carrying various frequencies corresponding simply to resonant frequencies of the detectors. It is generated in baseband with a bandwidth covering all KIDs and up-converted to microwave frequency (about several gigahertz) to feed the detectors. With THz radiation, the forward transmission coefficient (S21) of all KIDs varies and the variation can be measured through the comb signal. Fast Fourier transform (FFT) with pipeline structure will be used to process the baseband excitation signal in real time. Consequently, the radiation intensity can be estimated by monitoring the signal amplitude and phase of the corresponding frequency channels. In this paper we will present mainly the design ofan electronic readout system for the 8×8 pixel array.
    Proceedings of SPIE - The International Society for Optical Engineering 12/2012; DOI:10.1117/12.999786 · 0.20 Impact Factor
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    ABSTRACT: Superconducting tunnel junctions are good candidates for the direct detection of terahertz signals. In this paper, the direct detection behavior of Nb-based superconducting tunnel junctions at 493GHz is demonstrated. The performance of the detector is evaluated in several aspects, including noise characteristics, current response and frequency response.
    2012 International Conference on Microwave and Millimeter Wave Technology (ICMMT); 05/2012
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    ABSTRACT: To understand concentrations of perfluorinated compounds (PFCs) in aquatic products, and risks to human health, concentrations of 12 PFCs were measured in edible tissues of aquatic products collected from Tianjin, China, a typical industrial area on the western Bohai Sea. Perfluorooctane sulfonate (PFOS) was the predominant PFC. Concentrations of PFOS in aquatic products from Tianjin Binhai New Area (TBNA) ranged from
    Human and Ecological Risk Assessment 11/2011; 17(6):1279-1291. DOI:10.1080/10807039.2011.618395 · 1.08 Impact Factor
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    ABSTRACT: Concentrations of metals and arsenic in farmland soils along the Yanghe River, upstream of Guanting Reservoir, were evaluated using fuzzy comprehensive assessment (FCA). FCA is an emerging methodology for assessing environmental status based on fuzzy logic which can model linguistic data and represent chaotic conditions. The ratio of concentrations of metals and arsenic (As) in surface soils of farmland along the Yanghe River to the corresponding reference values decreased in the order Cd>Zn>Cr>Ni>Pb>Cu>As. Based on the FCA, 86% of surface soils along the Yanghe River were classified as grade C, which is suitable for forestry with a greater absorption capacity, suggesting that most farmland along the Yanghe River has to be abandoned as farmland. In order to improve the quality of soil along the Yanghe River and avoid degeneration of water quality in the river and the Guanting Reservoir, remediation of farmland soils along the river is suggested.
    Chemistry and Ecology 10/2011; 27(5):415-426. DOI:10.1080/02757540.2011.595711 · 1.18 Impact Factor
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    ABSTRACT: Epigenetic modifications are thought to be important for gene expression changes during development and aging. However, besides the Sir2 histone deacetylase in somatic tissues and H3K4 trimethylation in germlines, there is scant evidence implicating epigenetic regulations in aging. The insulin/IGF-1 signaling (IIS) pathway is a major life span regulatory pathway. Here, we show that progressive increases in gene expression and loss of H3K27me3 on IIS components are due, at least in part, to increased activity of the H3K27 demethylase UTX-1 during aging. RNAi of the utx-1 gene extended the mean life span of C. elegans by ~30%, dependent on DAF-16 activity and not additive in daf-2 mutants. The loss of utx-1 increased H3K27me3 on the Igf1r/daf-2 gene and decreased IIS activity, leading to a more "naive" epigenetic state. Like stem cell reprogramming, our results suggest that reestablishment of epigenetic marks lost during aging might help "reset" the developmental age of animal cells.
    Cell metabolism 08/2011; 14(2):161-72. DOI:10.1016/j.cmet.2011.07.001 · 16.75 Impact Factor
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    ABSTRACT: Twin SIS (superconductor-insulator-superconductor) junctions, with a simple structure, yet large bandwidth and low noise temperature, have been widely used in millimeter- and submillimeter-wave heterodyne mixers. With increasing frequency, however, the length of the tuning inductance connecting the two individual SIS junctions becomes short while the junction area remains fixed. With a relatively short tuning inductance, the effect of the junction's spreading inductance becomes non-negligible, and device fabrication becomes more difficult. By adopting vertically stacked SIS junctions (VSJs), which have an equivalent geometric capacitance inversely proportional to the junction number, it becomes feasible to increase the junction tuning inductance. In this paper, we report on the design, fabrication, and characterization of twin Nb/Al-AlOx/Nb/Al-AlOx/Nb VSJs for the 500-GHz frequency band.
    IEEE Transactions on Applied Superconductivity 07/2011; 21(3-21):663 - 666. DOI:10.1109/TASC.2010.2096493 · 1.32 Impact Factor
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    ABSTRACT: Concentrations of perfluorooctanesulfonate (PFOS), perfluorooctanoic acid (PFOA) and other perfluorinated compounds (PFCs) were measured in water and sediment from coastal Bohai Bay and surrounding rivers flowing into the bay. Of the 15 PFCs measured, PFOS and PFOA were detected with the greatest frequency. Concentrations in water ranged from<0.2 to 31 ng·L−1 and<1.0 to 82 ng·L−1 for PFOS and PFOA, respectively. Concentrations of PFOS and PFOA in sediments ranged from<0.1 to 2.0 ng·g−1 dw and<0.1 to 0.5 ng·g−1 dw, respectively. Concentrations of PFCs in Bohai Bay were less than those observed in other areas in Asia, but greater concentrations of ∑PFCs were observed in the Dalin River with concentrations increasing from upstream to downstream, and the greatest concentrations in sediment were observed in tidal flats. The ratio of ∑PFCs in sediment and water indicated that sediment could serve as a significant sink for PFUnA.
    Chemistry and Ecology 04/2011; 27(2):165-176. DOI:10.1080/02757540.2010.547485 · 1.18 Impact Factor
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    ABSTRACT: A case study of the cancer risk to humans posed by persistent organic pollutants (POPs) in an industrial area of China, which has a long history of contamination from many sources, is presented. Relatively great concentrations of POPs around the chemical industrial parks have the potential to be chronically carcinogenic to local people. Sixteen individual PAHs listed for priory control by the U.S. Environmental Protection Agency (USEPA), metabolites of DDTs, and isomers of HCHs were measured in soils and a human health risk assessment was conducted by use of USEPA exposure models for children and adults, respectively. Geostatistical methods were used to simulate the spatial diffusion of potential carcinogenic risk, and non-parametric Mann-Whitney U and Kruskal-Wallis tests were employed to analyze the impact of point sources on the surrounding area. The mean value of the sum of Excess Lifetime Cancer Risk (Sigma ELCR) exceeded the generally acceptable risk level of 1.0E-06 recommended by the USEPA for
    Human and Ecological Risk Assessment 10/2010; 16. DOI:10.1080/10807039.2010.512238 · 1.08 Impact Factor
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    ABSTRACT: Rhesus macaque is a widely used primate model organism. Its genome annotations are however still largely comparative computational predictions derived mainly from human genes, which precludes studies on the macaque-specific genes, gene isoforms or their regulations. Here we took advantage of histone H3 lysine 4 trimethylation (H3K4me3)'s ability to mark transcription start sites (TSSs) and the recently developed ChIP-Seq and RNA-Seq technology to survey the transcript structures. We generated 14,013,757 sequence tags by H3K4me3 ChIP-Seq and obtained 17,322,358 paired end reads for mRNA, and 10,698,419 short reads for sRNA from the macaque brain. By integrating these data with genomic sequence features and extending and improving a state-of-the-art TSS prediction algorithm, we ab initio predicted and verified 17,933 of previously electronically annotated TSSs at 500-bp resolution. We also predicted approximately 10,000 novel TSSs. These provide an important rich resource for close examination of the species-specific transcript structures and transcription regulations in the Rhesus macaque genome. Our approach exemplifies a relatively inexpensive way to generate a reasonably reliable TSS map for a large genome. It may serve as a guiding example for similar genome annotation efforts targeted at other model organisms.
    Nucleic Acids Research 10/2010; 39(4):1408-18. DOI:10.1093/nar/gkq956 · 8.81 Impact Factor
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    ABSTRACT: Tianjin Bin Hai New Area (BHNA) is the third largest economic zone in China. This is an older industrial area that has been developing rapidly but with many historic sources of contamination. The concentrations of 16 individual polycyclic aromatic hydrocarbons (PAHs) listed for priority control by the US EPA were quantified in 105 surface soil samples by the use of gas chromatography mass spectrometry (GC/MS). Multivariate statistical methods were used to characterise the mixtures and make comparisons in the patterns among areas. Concentrations varied among areas, ranging from moderate to relatively high. The coefficients of determination between concentrations of individual PAHs and total concentration of PAH (∑ PAH) increased with the number of rings. The first three factors from the principal component analysis (PCA) explained 81.6% of the total variation, while ten higher molecular weight (HMW) PAHs’ loadings for factor 1 accounted for 51.0%. Based on the patterns of relative loading proportions of individual PAHs calculated by PCA, the primary sources were coal combustion, traffic emissions including gasoline, diesel oil, and the burning of natural gas. The spatial distribution of concentrations of fluorene had a poor spatial autocorrelation in the study area. The sites with the greatest potential risk due to exposure to PAHs were mainly distributed around the chemical industry parks.
    Chemistry and Ecology 02/2010; 26(1):35-48. DOI:10.1080/02757540903468094 · 1.18 Impact Factor
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    ABSTRACT: We introduced here a compact 500 GHz SIS (superconductor-insulator-superconductor) heterodyne receiver system developed for POST (portable submillimeter telescope). The system is proved to have a small volume to be integrated with the small Dewar, which is cooled by a compact close-cycled 100 mW@ 4 K cryo-cooler. Test results shows that a good LO coupling and low signal loss is achieved with a less than 250 K overall receiver noise at 500 GHz waveband.
    Microwave Conference, 2009. APMC 2009. Asia Pacific; 01/2010
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    ABSTRACT: The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) were determined by gas chromatography equipped with a mass spectrometry detector in 105 topsoil samples from an industrial area around Bohai Bay, Tianjin in the North of China. Results demonstrated that concentrations of PAHs in 104 soil samples from this area ranged from 68.7 to 5,590 ng g(-1) dry weight with a mean of summation Sigma16PAHs 814 +/- 813 ng g(-1), which suggests that there exists mid to high levels of PAH contamination. The concentration of summation Sigma16PAHs in one soil sample from Tianjin Port was exceptionally high (48,700 ng g(-1)). Ninety-three of the 105 soil samples were considered to be contaminated with PAHs (>200 ng g(-1)), and 25 were heavily polluted (>1,000 ng g(-1)). The sites with high PAHs concentration are mainly distributed around chemical industry parks and near highways. Two low molecular weight PAHs, naphthalene and phenanthrene, were the dominant components in the soil samples, which accounted for 22.1% and 10.7% of the summation Sigma16PAHs concentration, respectively. According to the observed molecular indices, house heating in winter, straw stalk combustion in open areas after harvest, and petroleum input were common sources of PAHs in this area, while factory discharge and vehicle exhaust were the major sources around chemical industrial parks and near highways. Biological processes were probably another main source of low molecular weight PAHs.
    Environmental Monitoring and Assessment 11/2009; 158(1-4):581-92. DOI:10.1007/s10661-008-0606-x · 1.68 Impact Factor
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    ABSTRACT: We report on the mixing properties of waveguide SIS mixers with epitaxial NbN/AlN/NbN junctions and NbN/SiO<sub>2</sub>/NbTiN microstrips on MgO substrates. The superconducting transition temperature and 20-K resistivity of NbTiN film on the SiO<sub>2</sub> dielectric were 14.7 K and 175 muOmega cm, respectively. The junction tuning circuit was composed of an NbN/SiO<sub>2</sub>/NbTiN microstrip and two parallel-connected NbN/AlN/NbN junctions 0.9 mum in diameter. The critical current density and normal-state resistance of the fabricated NbN junction were 13 kA/cm<sup>2</sup> and 22 Omega, respectively. The heterodyne response was measured using 295- and 77-K blackbody sources, a local oscillator (LO) source, and a 25-mum-thick Kapton film as a beam splitter. An intermediate frequency (IF) amplifier with a bandwidth of 4-12 GHz was used in the measurements. The receiver noise temperature corrected for losses in the beam splitter and in the vacuum window of the cryocooler was 370 K at 860 GHz and was comparable to that of all-NbN mixes with NbN/MgO/NbN microstrips.
    IEEE Transactions on Applied Superconductivity 07/2009; DOI:10.1109/TASC.2009.2017886 · 1.32 Impact Factor
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    ABSTRACT: With a gap frequency of 1.4 THz, all-NbN Superconductor-Insulator-Superconductor (SIS) junctions are potentially applicable to sensitive heterodyne mixers for THz astronomy and atmospheric research. In this paper, we report the design, fabrication, and performance characterization of a 0.5-THz waveguide SIS mixer incorporating twin NbN/AlN/NbN junctions and an NbN/MgO/NbN tuning circuit with no impedance transformers. The noise performance of two NbN SIS junctions with different tuning inductances is measured, compared with the simulated results without and with the multiple Andreev reflection (MAR) effect taken into account, and also compared with the video detection response. In addition, the IF-output-power stability and aging effect of fabricated NbN SIS junctions are investigated.
    IEEE Transactions on Applied Superconductivity 07/2009; DOI:10.1109/TASC.2009.2018504 · 1.32 Impact Factor
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    ABSTRACT: The current state of concentrations of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) in China is presented. While products that are known to degrade to either PFOS or PFOA have been used in China, concentrations in environmental media have been reported to be relatively low across China. Greater concentrations of PFOS and PFOA were observed in southern and eastern China than in other areas of China. Concentrations of PFOS and PFOA were relatively great in the Huangpu River, with concentrations of 20.5 ng l and 1590 ng l, respectively. Surface waters of Dongguan and Shanghai were more contaminated by PFOS and PFOA than that of other cities. Dongguan was the only city in China in which PFOS value in surface water exceeded the water quality criterion, while PFOA concentration in Shanghai was 152 ng l. Similar to other contaminants, point-source pollution was also the common pattern of PFOS and PFOA contamination. Concentrations of PFOS in human blood in China were relatively greater in China than other countries, with drinking water contamination given as the most likely source. Concentrations of PFOS in human blood have increased from the 1980s to the 2000s, while such a trend was not observed for PFOA.
    Chemistry and Ecology 06/2009; 25(3):163-177. DOI:10.1080/02757540902918321 · 1.18 Impact Factor
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    ABSTRACT: Concentrations and composition of 16 polycyclic aromatic hydrocarbons (PAHs) listed for prior control by US EPA were detected by analyzing 28 surface soil samples from the chemical industrial areas of Tianjin Binhai New Area with a gas chromatography equipped with mass spectrometry (GC/MS). Relative concentrations of PAH compounds with different benzene rings and principal component analysis were used to identify the possible sources of soil PAHs. The maximum PAH concentration in all the samples was 5,991.7 ng x g(-1), with a mean values of 1,185.0 ng x g(-1). The concentrations of four and five rings PAH components were higher than that of the other PAH components in Tanggu and Hangu chemical industrial areas, and three rings PAH components were major PAHs in Dagang petroleum industrial area. There is significant positive correlation (n = 28, R2 = 0.847, p < 0.01) between PAH concentrations and total organic carbon (TOC) contents in the soil samples. Coal combustion was the dominant source of PAHs in chemical industrial areas, while petroleum volatilization and leakage were main contributors of PAHs in Dagang petroleum industrial area.
    Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 04/2009; 30(4):1166-72.
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    ABSTRACT: Aquatic humic substance (AHS) in landfill leachate is resistant to biodegradation, especially in anaerobic habitats. However, we reported here for the first time that AHS was completely biodegraded with the anaerobic ammonium oxidation (Anammox) process. As a result of aromatic-ring cleavage and mineralization, carboxylic and aliphatic organics were significantly produced, the contents of chromophores such as quinoid and ketone were remarkably decreased to decolorize the leachate, and produced carbon dioxide along with increasing carbonate was clearly presented. Of the degraded AHS of 137 mg L(-1), 51 mg L(-1) was owed to the oxidation with sulfate of 76 mg L(-1) as electron acceptor, and the rest to other metabolic mechanism. Isolation and identification of heterotrophic bacteria revealed a diversified consortium comprising four facultative anaerobic species, Bacillus sp., Paenibacillus sp., Bacteroides sp. and Staphylococcus sp., without sulfate-reducing bacteria detected. Their contribution to AHS biodegradation and sulfate reduction under the special conditions with high oxidization-reduction potential and insufficient electron acceptors has not been known yet. Further work is underway to investigate their properties and respective duties in the consortium.
    Chemosphere 02/2009; 74(10):1315-20. DOI:10.1016/j.chemosphere.2008.11.073 · 3.50 Impact Factor

Publication Stats

252 Citations
66.53 Total Impact Points

Institutions

  • 2009–2014
    • National Space Science
      Peping, Beijing, China
  • 2006–2012
    • Chinese Academy of Sciences
      • • Center for Molecular Systems Biology
      • • Graduate School
      • • State Key Laboratory of Urban and Regional Ecology
      • • Purple Mountain Observatory
      Peping, Beijing, China
  • 2008
    • Dalian Maritime University
      Lü-ta-shih, Liaoning, China
    • Chemical Abstracts Service (A division of the American Chemical Society)
      China, Maine, United States