The high resolution Terra SAR-X dataset was employed with DIn SAR and persistent scatterer interferometry（PSI） technique for subsidence monitoring in a mountainous area. For DInS AR technique, the generally used SRT...The high resolution Terra SAR-X dataset was employed with DIn SAR and persistent scatterer interferometry（PSI） technique for subsidence monitoring in a mountainous area. For DInS AR technique, the generally used SRTM and relief-DEM, which was derived from aerial topographic map, were used to evaluate the influence of external DEM. The results show that SRTM could not fully compensate the complex topography of the research area. The corner reflectors installed during the acquisition of SAR dataset were used to estimate the accuracy of geocoding. The terrain corrected geocoding results based on relief-DEM were much better than using SRTM, with the root mean square error（RMSE） being 6.35 m in X direction and 11.65 m in Y direction（both in UTM projection）, around one pixel of the multilooked intensity image to be geocoded. For PSI technique, the results from time-series analysis of multi-baseline differential interferograms were integrated to restrict only persistent scatterer candidates near the boundary of subsiding area for regression analysis. The results demonstrate that PSI can refine the boundary of subsidence, which could then be used to derive some angular parameters to help people to learn the law of subsidence caused by repeated excavation in this area.展开更多
An ionic liquid system of [Bmim]X/[Bmim]OH(X Cl,BF4,and PF6,) was developed for the hydroly-sis of ethylene carbonate to ethylene glycol. The important parameters,such as the variety of ionic liquids,molar ratio of [B...An ionic liquid system of [Bmim]X/[Bmim]OH(X Cl,BF4,and PF6,) was developed for the hydroly-sis of ethylene carbonate to ethylene glycol. The important parameters,such as the variety of ionic liquids,molar ratio of [Bmim]X to [Bmim]OH,amount of ionic liquid,molar ratio of water to ethylene carbonate,reaction tem-perature,pressure and reaction time,were investigated systematically. Excellent yield(>93%) and high selectivity(99.5%) of ethylene glycol were achieved. Under the optimum reaction conditions,the ionic liquid system could be reused at least five times and the selectivity of ethylene glycol remained higher than 99.5%.展开更多
In this study, the entire mitochondrial DNA(mtDNA) control region(CR) of Pholis fangi was amplified via polymerase chain reaction followed by direct sequencing. The length of the mtDNA CR consensus sequence of P. fang...In this study, the entire mitochondrial DNA(mtDNA) control region(CR) of Pholis fangi was amplified via polymerase chain reaction followed by direct sequencing. The length of the mtDNA CR consensus sequence of P. fangi was 853 bp in length. In accordance with the recognition sites as were previously reported in fish species, the mtDNA CR sequence of P. fangi can be divided into 3 domains, i.e., the extended terminal associated sequence(ETAS), the central conserved sequence block(CSB), and the CSB domain. In addition, the following structures were identified in the mtDNA CR sequence of P. fangi: 2 ETASs in the ETAS domain(TAS and cTAS), 6 CSBs in the central CSB domain(CSB-F to CSB-A), and 3 CSBs in the CSB domain(CSB-1 to CSB-3). These demonstrated that the structure of the mtDNA CR of P. fangi was substantially different from those of most other fish species. The mtDNA CR sequence of P. fangi contained one conserved region from 656 bp to 815 bp. Similar to most other fish species, P. fangi has no tandem repeat sequences in its mtDNA CR sequence. Phylogenetic analysis based on the complete mtDNA CR sequences showed that there were no genetic differences within P. fangi populations of the same geographical origin and between P. fangi populations of different geographical origins.展开更多
We investigate an adaptive cooperative protocol in a Two-Hop-Relay (THR) wireless system that combines the following: (1) adaptive relaying based on repetition coding; (2) single or two transmit antennas and one recei...We investigate an adaptive cooperative protocol in a Two-Hop-Relay (THR) wireless system that combines the following: (1) adaptive relaying based on repetition coding; (2) single or two transmit antennas and one receive antenna configurations for all nodes, each using high order constellation; (3) Bit-Interleaved Coded Modulation (BICM). We focus on a simple decoded relaying (i.e. no error correcting at a relay node) and simple signal quality thresholds for relaying. Then the impact of the two simple thresholds on the system performance is studied. Our results suggest that compared with the traditional scheme for direct transmission, the proposed scheme can increase average throughput in high spectral efficiency region with low implementa-tion-cost at the relay.展开更多
Novel tetra-methoxy resorcinarene tetra-hydrazide（TMRTH） has been synthesized and used as a reducing agent and a capping agent for the synthesis of water-dispersible stable palladium nanoparticles（PdNPs）.The TMRTH...Novel tetra-methoxy resorcinarene tetra-hydrazide（TMRTH） has been synthesized and used as a reducing agent and a capping agent for the synthesis of water-dispersible stable palladium nanoparticles（PdNPs）.The TMRTH-PdNPs were characterized by UV-Vis spectroscopy,transmission electron microscopy,energy-dispersive X-ray spectroscopy,and powder X-ray diffraction.The synthesized nanoparticles are polydispersible with a size of 5 ± 2 nm and were found to be recyclable over five cycles maintaining a catalytic activity in the Suzuki-Miyuara cross-coupling reaction.The nanocatalyst was superior in catalytic performance to conventional palladium catalysts with respect to reaction time,catalyst loading and recyclability.TMRTH-PdNPs show promise for their use in biological applications as they exhibit good antibacterial activity against gram-positive bacteria.展开更多
Vitamin E succinate was synthesized in organic solvents using a modified Novozym-435 as catalyst.In order to improve the catalytic performance of Novozym-435,the enzyme was modified using acetic anhydride, propionic a...Vitamin E succinate was synthesized in organic solvents using a modified Novozym-435 as catalyst.In order to improve the catalytic performance of Novozym-435,the enzyme was modified using acetic anhydride, propionic anhydride and succinic anhydride separately.We found that both the hydrolytic activity and the thermal stability of the modified Novozym-435 were enhanced compared with the unmodified enzyme.The modified Novozym-435 catalysts were used to synthesize the succinate derivative of vitamin E.Compared with the native Novozym-435,the catalytic activity of the modified novozym-435 in promoting the synthesis of vitamin E succinate was dramatically increased,with the novozym-435 modified with succinic anhydride（N435-S）as the most active catalyst.Conditions for the synthesis of vitamin E succinate were also optimized.A mixture of tert-butanol and DMSO（volume ratio of 2︰3）was the most suitable medium for the reaction,whereas the appropriate molar ratio of vitamin E to succinic anhydride and reaction temperature were 1︰5 and 40°C,respectively.Under these reaction conditions,the yield of vitamin E succinate reached 94.4%.N435-S could be reused for five batches.展开更多
Geological structures often exhibit smooth characteristics away from sharp discontinuities. One aim of geophysical inversion is to recover information about the smooth structures as well as about the sharp discontinui...Geological structures often exhibit smooth characteristics away from sharp discontinuities. One aim of geophysical inversion is to recover information about the smooth structures as well as about the sharp discontinuities. Because no specific operator can provide a perfect sparse representation of complicated geological models, hyper-parameter regularization inversion based on the iterative split Bregman method was used to recover the features of both smooth and sharp geological structures. A novel preconditioned matrix was proposed, which counteracted the natural decay of the sensitivity matrix and its inverse matrix was calculated easily. Application of the algorithm to synthetic data produces density models that are good representations of the designed models. The results show that the algorithm proposed is feasible and effective.展开更多
2-Methyl-4-methoxyaniline （MMA） was synthesized by one-pot method through the hydrogenation and Bamberger rearrangement of o-nitrotoluene in methanol using acidic ionic liquid and 3% Pt/C as catalyst system. The eff...2-Methyl-4-methoxyaniline （MMA） was synthesized by one-pot method through the hydrogenation and Bamberger rearrangement of o-nitrotoluene in methanol using acidic ionic liquid and 3% Pt/C as catalyst system. The effects of ionic liquid type, dosage of ionic liquid and 3% Pt/C, reaction temperature and reaction pressure on o-nitrotoluene conversion and MMA selectivity were investigated. The results indicated that the imidazolium-based acidic ionic liquid which contains SO3H-functionalized cation showed higher selectivity to MMA than other acidic ionic liquids used in this work. Using 1-（propyl-3-sulfonate）-3-methylimidazolium hydrosulfate （[HSO3-pmim][HSO4]） as the acid catalyst, the selectivity to MMA was as high as 67.6% at 97.8% of o-nitrotoluene conversion. As 3% Pt/C increased from 0.01 g to 0.025 g, the selectivity to MMA decreased from 73.4% to 62.5%, because of the hydrogenation of intermediate o-methyl-phenylhydroxylamine to o-toluidine becoming more dominant. An increase in hydrogen pressure also had obviously dramatic effect in lowering the MMA selectivity. After easy separation from the products, the catalyst system could be reused at least 3 times.展开更多
To investigate the seismic behavior of autoclaved aerated concrete load-bearing masonry wall(AACLMW), a piece of control block wall without constructional measures and five pieces of block walls with different constru...To investigate the seismic behavior of autoclaved aerated concrete load-bearing masonry wall(AACLMW), a piece of control block wall without constructional measures and five pieces of block walls with different constructional measures were tested under low reversed cyclic loading which imitated low to moderate earthquake force. The seismic behavior of AACLMW with different constructional measures in terms of failure mode, hysteretic curve, deformation capacity and displacement ductility was studied and compared with that without constructional measures. The experimental results indicate that the constructional measures comprising constructional columns and horizontal concrete strips are effective for improving the seismic behavior of AACLMW. The study in this paper can provide a reliable experimental basis for further analysis and engineering application of AACLMW in the future.展开更多
Simple sequences repeat （SSR） molecular maker, as a new type of DNA molecular marker, the second generation based on the polymerase chain reaction （PCR）, is valuable and of great potential as genetic markers for i...Simple sequences repeat （SSR） molecular maker, as a new type of DNA molecular marker, the second generation based on the polymerase chain reaction （PCR）, is valuable and of great potential as genetic markers for its characteristics of abundant quantity, high polymorphic, reproducibility, specific site amplification, high occurring frequency, and co-dominant inheritance etc. This paper outlined its principles and characteristics, and introduced its application to variety identification, phylogenetic relationship analysis, genetic diversity analysis, DNA fingerprinting and linkage map constructing etc. in recent years in Citrus and its close relatives.展开更多
A relatively simple plug-and-play control system of quantum key distribution （QKD） based on PCI7300 card is demonstrated, including mechanism design, key generation and key acquisition. The system works very well at...A relatively simple plug-and-play control system of quantum key distribution （QKD） based on PCI7300 card is demonstrated, including mechanism design, key generation and key acquisition. The system works very well at the repetition frequency of 1 MHz, and the key generation rate is 100 k/s. A visibility of better than 95% over 50 km-long fiber at 1.31 gm is obtained, which is stable under ordinary lab conditions for 24 h without any feedback control or adjustment. The presented system is a quite promising candidate to realize the QKD in the future.展开更多
Regulating the selectivity of catalysts in selective hydrogenation reactions at the atomic level is highly desirable but remains a grand challenge. Here we report a simple and practical strategy to synthesize a monoli...Regulating the selectivity of catalysts in selective hydrogenation reactions at the atomic level is highly desirable but remains a grand challenge. Here we report a simple and practical strategy to synthesize a monolithic single-atom catalyst(SAC) with isolated Pd atoms supported on bulk nitrogen-doped carbon foams(Pd-SAs/CNF). Moreover, we demonstrate that the single-atom Pd sites with unique electronic structure endow Pd-SAs/CNF with an isolated site effect, leading to excellent activity and selectivity in 4-nitrophenylacetylene semi-hydrogenation reaction. In addition, benefiting from the great integrity and excellent mechanical strength, monolithic Pd-SAs/CNF catalyst is easy to separate from the reaction system for conducting the subsequent recycling. The cyclic test demonstrates the excellent reusability and stability of monolithic Pd-SAs/CNF catalyst.The discovery of isolated site effect provides a new approach to design highly selective catalysts. And the development of monolithic SACs provides new opportunities to advance the practical applications of single-atom catalysts.展开更多
We examine the repeatabilities of oblique-incidence reflectivity difference(OIRD) method for label-free detecting biological molecular interaction using protein microarrays.The experimental results show that the repea...We examine the repeatabilities of oblique-incidence reflectivity difference(OIRD) method for label-free detecting biological molecular interaction using protein microarrays.The experimental results show that the repeatabilities are the same in a given microarray or microarray-microarray and are consistent,indicating that OIRD is a promising label-free detection technique for biological microarrays.展开更多
基金Project(51174191)supported by the National Natural Science Foundation of ChinaProject(2013CB227904)supported by the National Basic Research Program of ChinaProject(2012QNB09)supported by Fundamental Research Funds for the Central Universities,China
文摘The high resolution Terra SAR-X dataset was employed with DIn SAR and persistent scatterer interferometry（PSI） technique for subsidence monitoring in a mountainous area. For DInS AR technique, the generally used SRTM and relief-DEM, which was derived from aerial topographic map, were used to evaluate the influence of external DEM. The results show that SRTM could not fully compensate the complex topography of the research area. The corner reflectors installed during the acquisition of SAR dataset were used to estimate the accuracy of geocoding. The terrain corrected geocoding results based on relief-DEM were much better than using SRTM, with the root mean square error（RMSE） being 6.35 m in X direction and 11.65 m in Y direction（both in UTM projection）, around one pixel of the multilooked intensity image to be geocoded. For PSI technique, the results from time-series analysis of multi-baseline differential interferograms were integrated to restrict only persistent scatterer candidates near the boundary of subsiding area for regression analysis. The results demonstrate that PSI can refine the boundary of subsidence, which could then be used to derive some angular parameters to help people to learn the law of subsidence caused by repeated excavation in this area.
基金Supported by the National High Technology Research and Development Program of China（2006AA06Z317） National Natural Science Foundation of China（20876162）+3 种基金 National Basic Research Program of China（2009CB219901） National Key Technology Research and Development Program（2008BAF33B04） National Science Fund of China（21006117） Science and Technology Project of Beijing（Y090081135）
文摘An ionic liquid system of [Bmim]X/[Bmim]OH(X Cl,BF4,and PF6,) was developed for the hydroly-sis of ethylene carbonate to ethylene glycol. The important parameters,such as the variety of ionic liquids,molar ratio of [Bmim]X to [Bmim]OH,amount of ionic liquid,molar ratio of water to ethylene carbonate,reaction tem-perature,pressure and reaction time,were investigated systematically. Excellent yield(>93%) and high selectivity(99.5%) of ethylene glycol were achieved. Under the optimum reaction conditions,the ionic liquid system could be reused at least five times and the selectivity of ethylene glycol remained higher than 99.5%.
基金supported by the Public Science and Technology Research Funds Projects of Ocean (Nos. 201305043 and 201405010)
文摘In this study, the entire mitochondrial DNA(mtDNA) control region(CR) of Pholis fangi was amplified via polymerase chain reaction followed by direct sequencing. The length of the mtDNA CR consensus sequence of P. fangi was 853 bp in length. In accordance with the recognition sites as were previously reported in fish species, the mtDNA CR sequence of P. fangi can be divided into 3 domains, i.e., the extended terminal associated sequence(ETAS), the central conserved sequence block(CSB), and the CSB domain. In addition, the following structures were identified in the mtDNA CR sequence of P. fangi: 2 ETASs in the ETAS domain(TAS and cTAS), 6 CSBs in the central CSB domain(CSB-F to CSB-A), and 3 CSBs in the CSB domain(CSB-1 to CSB-3). These demonstrated that the structure of the mtDNA CR of P. fangi was substantially different from those of most other fish species. The mtDNA CR sequence of P. fangi contained one conserved region from 656 bp to 815 bp. Similar to most other fish species, P. fangi has no tandem repeat sequences in its mtDNA CR sequence. Phylogenetic analysis based on the complete mtDNA CR sequences showed that there were no genetic differences within P. fangi populations of the same geographical origin and between P. fangi populations of different geographical origins.
基金Supported by the National Natural Science Foundation of China (No.60496311) and partially supported by the B3G project (2003AA123310).
文摘We investigate an adaptive cooperative protocol in a Two-Hop-Relay (THR) wireless system that combines the following: (1) adaptive relaying based on repetition coding; (2) single or two transmit antennas and one receive antenna configurations for all nodes, each using high order constellation; (3) Bit-Interleaved Coded Modulation (BICM). We focus on a simple decoded relaying (i.e. no error correcting at a relay node) and simple signal quality thresholds for relaying. Then the impact of the two simple thresholds on the system performance is studied. Our results suggest that compared with the traditional scheme for direct transmission, the proposed scheme can increase average throughput in high spectral efficiency region with low implementa-tion-cost at the relay.
基金financial assistance provided by UGC(University Grant Commission)DRDO (Defence Research Development Organisation),New Delhi
文摘Novel tetra-methoxy resorcinarene tetra-hydrazide（TMRTH） has been synthesized and used as a reducing agent and a capping agent for the synthesis of water-dispersible stable palladium nanoparticles（PdNPs）.The TMRTH-PdNPs were characterized by UV-Vis spectroscopy,transmission electron microscopy,energy-dispersive X-ray spectroscopy,and powder X-ray diffraction.The synthesized nanoparticles are polydispersible with a size of 5 ± 2 nm and were found to be recyclable over five cycles maintaining a catalytic activity in the Suzuki-Miyuara cross-coupling reaction.The nanocatalyst was superior in catalytic performance to conventional palladium catalysts with respect to reaction time,catalyst loading and recyclability.TMRTH-PdNPs show promise for their use in biological applications as they exhibit good antibacterial activity against gram-positive bacteria.
基金Supported by the Fundamental Research Funds for the Central Universities and the State Key Development Program for Basic Research of China(2007CB714304)
文摘Vitamin E succinate was synthesized in organic solvents using a modified Novozym-435 as catalyst.In order to improve the catalytic performance of Novozym-435,the enzyme was modified using acetic anhydride, propionic anhydride and succinic anhydride separately.We found that both the hydrolytic activity and the thermal stability of the modified Novozym-435 were enhanced compared with the unmodified enzyme.The modified Novozym-435 catalysts were used to synthesize the succinate derivative of vitamin E.Compared with the native Novozym-435,the catalytic activity of the modified novozym-435 in promoting the synthesis of vitamin E succinate was dramatically increased,with the novozym-435 modified with succinic anhydride（N435-S）as the most active catalyst.Conditions for the synthesis of vitamin E succinate were also optimized.A mixture of tert-butanol and DMSO（volume ratio of 2︰3）was the most suitable medium for the reaction,whereas the appropriate molar ratio of vitamin E to succinic anhydride and reaction temperature were 1︰5 and 40°C,respectively.Under these reaction conditions,the yield of vitamin E succinate reached 94.4%.N435-S could be reused for five batches.
基金Projects(41174061,41374120)supported by the National Natural Science Foundation of China
文摘Geological structures often exhibit smooth characteristics away from sharp discontinuities. One aim of geophysical inversion is to recover information about the smooth structures as well as about the sharp discontinuities. Because no specific operator can provide a perfect sparse representation of complicated geological models, hyper-parameter regularization inversion based on the iterative split Bregman method was used to recover the features of both smooth and sharp geological structures. A novel preconditioned matrix was proposed, which counteracted the natural decay of the sensitivity matrix and its inverse matrix was calculated easily. Application of the algorithm to synthetic data produces density models that are good representations of the designed models. The results show that the algorithm proposed is feasible and effective.
基金Supported by the National Natural Science Foundation of China （21106134） and the Natural Science Foundation of Zlaejlang Province （Y4100671）.
文摘2-Methyl-4-methoxyaniline （MMA） was synthesized by one-pot method through the hydrogenation and Bamberger rearrangement of o-nitrotoluene in methanol using acidic ionic liquid and 3% Pt/C as catalyst system. The effects of ionic liquid type, dosage of ionic liquid and 3% Pt/C, reaction temperature and reaction pressure on o-nitrotoluene conversion and MMA selectivity were investigated. The results indicated that the imidazolium-based acidic ionic liquid which contains SO3H-functionalized cation showed higher selectivity to MMA than other acidic ionic liquids used in this work. Using 1-（propyl-3-sulfonate）-3-methylimidazolium hydrosulfate （[HSO3-pmim][HSO4]） as the acid catalyst, the selectivity to MMA was as high as 67.6% at 97.8% of o-nitrotoluene conversion. As 3% Pt/C increased from 0.01 g to 0.025 g, the selectivity to MMA decreased from 73.4% to 62.5%, because of the hydrogenation of intermediate o-methyl-phenylhydroxylamine to o-toluidine becoming more dominant. An increase in hydrogen pressure also had obviously dramatic effect in lowering the MMA selectivity. After easy separation from the products, the catalyst system could be reused at least 3 times.
基金Supported by Science and Technology Development Program of Tianjin(No.033112311)
文摘To investigate the seismic behavior of autoclaved aerated concrete load-bearing masonry wall(AACLMW), a piece of control block wall without constructional measures and five pieces of block walls with different constructional measures were tested under low reversed cyclic loading which imitated low to moderate earthquake force. The seismic behavior of AACLMW with different constructional measures in terms of failure mode, hysteretic curve, deformation capacity and displacement ductility was studied and compared with that without constructional measures. The experimental results indicate that the constructional measures comprising constructional columns and horizontal concrete strips are effective for improving the seismic behavior of AACLMW. The study in this paper can provide a reliable experimental basis for further analysis and engineering application of AACLMW in the future.
文摘Simple sequences repeat （SSR） molecular maker, as a new type of DNA molecular marker, the second generation based on the polymerase chain reaction （PCR）, is valuable and of great potential as genetic markers for its characteristics of abundant quantity, high polymorphic, reproducibility, specific site amplification, high occurring frequency, and co-dominant inheritance etc. This paper outlined its principles and characteristics, and introduced its application to variety identification, phylogenetic relationship analysis, genetic diversity analysis, DNA fingerprinting and linkage map constructing etc. in recent years in Citrus and its close relatives.
基金supported by the National Natural Science Foundation of China(Nos.61178010and10805006)the Fundamental Research Funds for the Central Universities(No.bupt2010zx04)the China Postdoctoral Science Foundation(No.20100480508)
文摘A relatively simple plug-and-play control system of quantum key distribution （QKD） based on PCI7300 card is demonstrated, including mechanism design, key generation and key acquisition. The system works very well at the repetition frequency of 1 MHz, and the key generation rate is 100 k/s. A visibility of better than 95% over 50 km-long fiber at 1.31 gm is obtained, which is stable under ordinary lab conditions for 24 h without any feedback control or adjustment. The presented system is a quite promising candidate to realize the QKD in the future.
基金supported by the National Key R&D Program of China (2018YFA0702003)the National Natural Science Foundation of China (21890383,21671117,21871159 and 21901135)+1 种基金the National Postdoctoral Program for Innovative Talents (BX20180160)the China Postdoctoral Science Foundation (2018M640113)。
文摘Regulating the selectivity of catalysts in selective hydrogenation reactions at the atomic level is highly desirable but remains a grand challenge. Here we report a simple and practical strategy to synthesize a monolithic single-atom catalyst(SAC) with isolated Pd atoms supported on bulk nitrogen-doped carbon foams(Pd-SAs/CNF). Moreover, we demonstrate that the single-atom Pd sites with unique electronic structure endow Pd-SAs/CNF with an isolated site effect, leading to excellent activity and selectivity in 4-nitrophenylacetylene semi-hydrogenation reaction. In addition, benefiting from the great integrity and excellent mechanical strength, monolithic Pd-SAs/CNF catalyst is easy to separate from the reaction system for conducting the subsequent recycling. The cyclic test demonstrates the excellent reusability and stability of monolithic Pd-SAs/CNF catalyst.The discovery of isolated site effect provides a new approach to design highly selective catalysts. And the development of monolithic SACs provides new opportunities to advance the practical applications of single-atom catalysts.
基金supported by the National Basic Research Program of China(Grant No. 2007CB935700)
文摘We examine the repeatabilities of oblique-incidence reflectivity difference(OIRD) method for label-free detecting biological molecular interaction using protein microarrays.The experimental results show that the repeatabilities are the same in a given microarray or microarray-microarray and are consistent,indicating that OIRD is a promising label-free detection technique for biological microarrays.
