The time course of the initiation of different types of apical primordia on the stem of wheat (Triticum aestivum L.) was investigated to establish a comprehensive pattern of apical primordium development and quantitat...The time course of the initiation of different types of apical primordia on the stem of wheat (Triticum aestivum L.) was investigated to establish a comprehensive pattern of apical primordium development and quantitative dynamic relationships among different primordium initiation. The results showed that the initiation of leaf and bracteal primordia took the S shape, and that of spikelet and floret took the rise stage of parabolic shape in relation to GDD (growing degree days after sowing) in wheat. The bracteal was much like vegetative rather than reproductive organ in terms of the dynamic pattern of primordium initiation. The progress of spikelet and floret primordium initiation could well reflect the characteristics of different genotypes and the impact of different ecological environments on wheat apical development. The integrated model of different primordium initiation in shoot of wheat was an S_shaped curvilinear, and could be divided into three sub_models. The number of leaf primordia was affected by both genotype and environment, while the numbers of bracteal, spikelet and floret primordia were affected mainly by environmental factors. Measured with mean thermochron, the rates of initiation of leaf, bracteal and spikelet primordia in normal planting were the highest among all the sowing date treatments. In contrast to the relationships among leaf, bracteal, spikelet and their initiation duration, the correlation between the number of floret and its initiation duration was highly significant.展开更多
[Objective] This study aimed to explore an effective method for rapid salt- extraction of high-quality genomic DNA from dried seeds of plants. [Method] Seeds of seven varieties of crops were ground into powder. A hund...[Objective] This study aimed to explore an effective method for rapid salt- extraction of high-quality genomic DNA from dried seeds of plants. [Method] Seeds of seven varieties of crops were ground into powder. A hundred milligrams of seed powder was added to extracting solution for high salt-extraction of genomic DNA. The yield and quality of extracted DNA were determined by using ultramicro UV/Vis spectrophotometer detection method, PCR and restriction enzyme digestion. [Result] About 619.67-1 811.21 ng of genomic DNA was extracted from per 100 mg of dried seed powder of seven varieties of conventional crops. A260/A280 ratios of the obtained DNA solution all ranged from 1.87 to 2.07, the purity and quality of PCR were suitable for PCR and restriction enzyme digestion. Clear target bands of specific endogenous gene fragments of seven varieties of crops were amplified by PCR, and the obtained DNA could be fully digested with EcoRV and Hindlll.[Conclusion] This method could be used for rapid extraction of high-quality genomic DNA from dried seeds.展开更多
The integration pattern and adjacent host sequences of the inserted pMThGH-transgene in the F4 hGH-transgeniccommon carp were extensively studied. Here we show that each F4 transgenic fish contained about 200 copies o...The integration pattern and adjacent host sequences of the inserted pMThGH-transgene in the F4 hGH-transgeniccommon carp were extensively studied. Here we show that each F4 transgenic fish contained about 200 copies of thepMThGH-transgene and the transgenes were integrated into the host genome generally with concatemers in a head-to-tail arrangement at 4-5 insertion sites. By using a method of plasmid rescue, four hundred copies of transgenes fromtwo individuals of F4 transgenic fish, A and B, were recovered and clarified into 6 classes. All classes of recoveredtransgenes contained either complete or partial pMThGH sequences. The class I, which comprised 83% and 84.5%respectively of the recovered transgene copies from fish A and B, had maintained the original configuration, indicatingthat most transgenes were faithfully inherited during the four generations of reproduction. The other five classes weredifferent from the original configuration in both molecular weight and restriction map, indicating that a few transgeneshad undergone mutation, rearrangement or deletion during integration and germline transmission. In the five types ofaberrant transgenes, three flanking sequences of the host genome were analyzed. These sequences were common carpβ-actin gene, common carp DNA sequences homologous to mouse phosphoglycerate kinase-1 and human epidermalkeratin 14, respectively.展开更多
To improve the bit error rate(BER) performance of multiple input multiple output(MIMO) systems with low complexity, a three-branch transmission scheme employing 8-weighted-type fractional Fourier transform(8-WFRFT) mo...To improve the bit error rate(BER) performance of multiple input multiple output(MIMO) systems with low complexity, a three-branch transmission scheme employing 8-weighted-type fractional Fourier transform(8-WFRFT) module is proposed. In the proposed scheme, the original signal is first decomposed into eight sub-signals and then merged into three component signals by the same carrier pattern. The three signals have mathematical constraint relations among themselves that can counteract the channel fading. They are simultaneously transmitted via three independent antennas after delay regulating. At the receiver, an inverse 8-WFRFT module is employed to obtain the estimated original signal by processing the received signal. Then, the bit error rate(BER) performance, transmitting power, transmission rate, power spectrum and computational complexity of the proposed scheme are analysed in detail. Numerical results show that the proposed scheme has a superior performance compared to STBC based three-antenna transmission scheme, in terms of BER performance.展开更多
We studied the hydrogenation of 2‐ethylanthraquinone(eAQ) over Pd/SiO2/COR(COR = cordierite) monometallic and Pd‐M/SiO2/COR(M = Ni, Fe, Mn, and Cu) bimetallic monolithic catalysts, which were prepared by the c...We studied the hydrogenation of 2‐ethylanthraquinone(eAQ) over Pd/SiO2/COR(COR = cordierite) monometallic and Pd‐M/SiO2/COR(M = Ni, Fe, Mn, and Cu) bimetallic monolithic catalysts, which were prepared by the co‐impregnation method. Detailed investigations showed that the particle sizes and structures of the Pd‐M(M = Ni, Fe, Mn, and Cu) bimetallic monolithic catalysts were great‐ly affected by the second metal M and the mass ratio of Pd to the second metal M. By virtue of the small particle size and the strong interaction between Pd and Ni of Pd‐Ni alloy, Pd‐Ni bimetallic monolithic catalysts with the mass ratio of Pd/Ni = 2 achieved the highest H2O2 yield(7.5 g/L) and selectivity(95.3%). Moreover, density functional theory calculations were performed for eAQ ad‐sorption to gain a better mechanistic understanding of the molecule‐surface interactions between eAQ and the Pd(1 1 1) or PdM(1 1 1)(M = Ni, Fe, Mn, and Cu) surfaces. It was found that the high activity of the bimetallic Pd‐Ni catalyst was a result of strong chemisorption between Pd3Ni1(1 1 1) and the carbonyl group of eAQ.展开更多
A recombinant plasmid (pcMTsGH) containing the common carp methlothionein promoter (cMT) and salmon growth hormone gene (sGH) was microinjected into common carp fertilized eggs and embryos to optimize the conditions f...A recombinant plasmid (pcMTsGH) containing the common carp methlothionein promoter (cMT) and salmon growth hormone gene (sGH) was microinjected into common carp fertilized eggs and embryos to optimize the conditions for producing transgenic fish. Several key elements were found to have significant effects on the integration of exogenous gene. These elements include forms and doses of pcMTsGH gene microinjected, stages of embryo at which microinjection conducted and pretreatment of fertilized eggs for microinjection. The results show that, in producing transgenic fish, (1) the best time for microinjection is late onecell stage, (2) the most appropriate dose of pcMTsGH gene for microinjection is around 106~107 copies; (3) the hatching rate rises up when the gene is microinjected into the eggs whose chorions are removed, but the integration rate has no significant changes before and after the removal of egg chorions.展开更多
The effects of Ni coating on the mechanical behaviors of single graphene sheet and their embedded Al matrix composites under axial tension are investigated using molecular dynamics (MD) simulation method. The result...The effects of Ni coating on the mechanical behaviors of single graphene sheet and their embedded Al matrix composites under axial tension are investigated using molecular dynamics (MD) simulation method. The results show that the Young's moduli and tensile strength of graphene obviously decrease after Ni coating. The results also show that the mechanical properties of Al matrix can be obviously increased by embedding a single graphene sheet. From the simulation, we also find that the Young's modulus and tensile strength of the Ni-coated graphene/Al composite is obviously larger than those of the uncoated graphene/Al composite. The increased magnitude of the Young's modulus and tensile strength of graphene/Al composite are 52.27% and 32.32% at 0.01 K, respectively, due to Ni coating. By exploring the effects of temperature on the mechanical properties of single graphene sheet and their embedded Al matrix composites, it is found that the higher temperature leads to the lower critical strain and tensile strength.展开更多
As it is impossible to assume complete rationality in a social dilemma situation, the assumption of bounded rationality is appropriate. Under the bounded rationality, it would be reasonable to assume that one behaves ...As it is impossible to assume complete rationality in a social dilemma situation, the assumption of bounded rationality is appropriate. Under the bounded rationality, it would be reasonable to assume that one behaves according to the heuristics principle. The group identity effect in a social dilemma situation might be very important in order to attain cooperation. The aim of this study was to clarify how to promote a cooperative behavior by avoiding a social dilemma situation. The group heuristics was taken into account, and it was explored how the group heuristics promotes a cooperative behavior in a social dilemma situation. As a result of a two-person game theory experiment, the group heuristics was found to play an important role in a social dilemma situation, and enhance a cooperative behavior. For the following three cases, the higher cooperation rate was attained at the latter half of the experiment: (a) mutual in-group condition, (b) one-way in-group condition, and (f) one-way unknown condition (in-group). In conclusion, the consciousness of in-group membership might help to promote actively mutual cooperation.展开更多
AIM:To analyse the possible association of various Helicobacter species and certain common gut bacteria in patients with Meckel's diverticulum and appendicitis.METHODS:A nested-polymerase chain reaction (PCR),spec...AIM:To analyse the possible association of various Helicobacter species and certain common gut bacteria in patients with Meckel's diverticulum and appendicitis.METHODS:A nested-polymerase chain reaction (PCR),specific to 16S rRNA of the Helicobacter genus,was performed on paraffin embedded samples,50 with acute appendicitis,50 normal appendixes,and 33 Meckel's diverticulum with gastric heterotopia and/or ulcer.Helicobacter genus positive samples were sequenced for species identification.All samples were also analysed for certain gut bacteria by PCR.RESULTS:Helicobacter pullorum DNA was found in one out of 33 cases and Enterobacteria in two cases of Meckel's diverticulum.Helicobacter pylori (H.pylori) was found in three,Enterobacter in 18,and Bacteroides in 19 out of 100 appendix samples by PCR.Enterococcus was not found in any MD or appendix samples.All H.pylori positive cases were from normal appendixes.CONCLUSION:Helicobacter is not an etiological agent in the pathogenesis of symptomatic Meckel's diverticulum or in acute appendicitis.展开更多
A new fractal image compression algorithm based on high frequency energy (HFE) partitioning andmatched domain block searching is presented to code synthetic aperture radar (SAR) imagery. In the hybridcoding algorithm,...A new fractal image compression algorithm based on high frequency energy (HFE) partitioning andmatched domain block searching is presented to code synthetic aperture radar (SAR) imagery. In the hybridcoding algorithm, the original SAR image is decomposed to low frequency components and high frequencycomponents by wavelet transform (WT). Then the coder uses HFE of block to partition and searchthe matched domain block for each range block to code the low frequency components. For the high frequencycomponents, a modified embedded zero-tree wavelet coding algorithm is applied. Experiment resultsshow that the proposed coder obtains about 0. 3dB gain when compared to the traditional fractal coderbased on the quadtree partition. Moreover, the subjective visual quality of the reconstructed SAR imageof the proposed coder outperforms that of the traditional fractal coders in the same compression ratio(CR).展开更多
With the vigorous development of China' s tourism industry, the rapid expansion of universities and tourism management enrollment has trained a large number of tourism professionals, and promoted the rapid developmen...With the vigorous development of China' s tourism industry, the rapid expansion of universities and tourism management enrollment has trained a large number of tourism professionals, and promoted the rapid development of tourism. However, the increasing number of colleges and universities tourism management enrollment and the expansion of the tourism industry have not been able to meet the demand for high-class expertise, which partly due to low tourism management teaching quality of colleges and universities. Whereas the school-enterprise cooperation in personnel training mode is one kind of tourism management that can effectively improve the quality of teaching of important measures.展开更多
The mathematic model of combined converter with two different flow modes of gas-cooled reactor was established. The effects of gas flow mode in gas-cooled reactor on combined converter was investigated with the yield ...The mathematic model of combined converter with two different flow modes of gas-cooled reactor was established. The effects of gas flow mode in gas-cooled reactor on combined converter was investigated with the yield of methanol was 1 400 kt/a. The results show that if the flow mode of the cooling pipe gas and the catalytic bed gas change from countercurrent to concurrent, the catalytic bed temperature distribution does not fit the most optimum temperature curve of reversible exothermic reaction and the heat duty of heat changer in whole process increased seriously, which means that there is much more equipment investment and more operating cost. The gas flow mode of gas-cooled reactor affects the methanol yield slightly. There- fore, the countercurrent gas flow mode of gas-cooled reactor is more lucrative in the combined converter process.展开更多
The framework of digital signature based on qualified certificates and X. 509 architecture is known to have many security risks. Moreover, the fraud prevention mechanism is fragile and does not provide strong guarante...The framework of digital signature based on qualified certificates and X. 509 architecture is known to have many security risks. Moreover, the fraud prevention mechanism is fragile and does not provide strong guarantees that can be necessary for flow of legal documents. Mediated signatures have been proposed as a mechanism to effectively disable signature cards. In this paper we propose further mechanisms that can be applied on top of mediated RSA, compatible with the standard format, but providing security guarantees even in the case when RSA becomes broken or the keys are compromised. The solution is immune tokleptographic attacks as only deterministic algorithms are used on user's side.展开更多
Severe growth abnormalities including shoot stunting, leaf blade reduction and flower bud failure of Brussels sprout were observed in Poland. The presence of phytoplasma in diseased as well as in healthy looking plant...Severe growth abnormalities including shoot stunting, leaf blade reduction and flower bud failure of Brussels sprout were observed in Poland. The presence of phytoplasma in diseased as well as in healthy looking plants, was demonstrated by nested polymerase chain reaction assay employing phytoplasma universal rRNA primer pairs-P1/P7 followed by R16F2n/R16R2. Products of PCR primed by R 16F2n/R 16R2 primer pair from naturally infected Brussels sprouts were sequenced. Comparison of the obtained 16S rDNAs revealed high nucleotide sequence identity between analyzed phytoplasma isolates (99.8%-100%). They were also nearly identical with the sequences of other phytoplasmas isolates from sub-group 16SrI-B, and they were classified as members of "Candidatus Phytoplasma asteris".展开更多
The information technology assisted English teaching has witnessed fast development and entered the classroom through course integration process. The integration radically changes the essence of college English teachi...The information technology assisted English teaching has witnessed fast development and entered the classroom through course integration process. The integration radically changes the essence of college English teaching, and therefore the traditional teaching mode has been challenged. In other words, information technology has become an integral part in today' s web-based college English teaching classroom. This paper attempts to read in detail about the Boyer' s teaching academic thought. Combined with the current situation of college English teaching, this paper discusses the feasibility of teaching academic thinking is applied to the English network teaching. A model is established by exploratory factor analysis and confirmatory factor analysis. Through the way of questionnaire to the research on the college English network teaching, so as to put forward the solutions and improve the quality of teaching.展开更多
文摘The time course of the initiation of different types of apical primordia on the stem of wheat (Triticum aestivum L.) was investigated to establish a comprehensive pattern of apical primordium development and quantitative dynamic relationships among different primordium initiation. The results showed that the initiation of leaf and bracteal primordia took the S shape, and that of spikelet and floret took the rise stage of parabolic shape in relation to GDD (growing degree days after sowing) in wheat. The bracteal was much like vegetative rather than reproductive organ in terms of the dynamic pattern of primordium initiation. The progress of spikelet and floret primordium initiation could well reflect the characteristics of different genotypes and the impact of different ecological environments on wheat apical development. The integrated model of different primordium initiation in shoot of wheat was an S_shaped curvilinear, and could be divided into three sub_models. The number of leaf primordia was affected by both genotype and environment, while the numbers of bracteal, spikelet and floret primordia were affected mainly by environmental factors. Measured with mean thermochron, the rates of initiation of leaf, bracteal and spikelet primordia in normal planting were the highest among all the sowing date treatments. In contrast to the relationships among leaf, bracteal, spikelet and their initiation duration, the correlation between the number of floret and its initiation duration was highly significant.
基金Supported by Project of Common Safety Assessment Technology for Genetically Modified Organisms of the Ministry of Agriculture of PRC (2011ZX08011-006)~~
文摘[Objective] This study aimed to explore an effective method for rapid salt- extraction of high-quality genomic DNA from dried seeds of plants. [Method] Seeds of seven varieties of crops were ground into powder. A hundred milligrams of seed powder was added to extracting solution for high salt-extraction of genomic DNA. The yield and quality of extracted DNA were determined by using ultramicro UV/Vis spectrophotometer detection method, PCR and restriction enzyme digestion. [Result] About 619.67-1 811.21 ng of genomic DNA was extracted from per 100 mg of dried seed powder of seven varieties of conventional crops. A260/A280 ratios of the obtained DNA solution all ranged from 1.87 to 2.07, the purity and quality of PCR were suitable for PCR and restriction enzyme digestion. Clear target bands of specific endogenous gene fragments of seven varieties of crops were amplified by PCR, and the obtained DNA could be fully digested with EcoRV and Hindlll.[Conclusion] This method could be used for rapid extraction of high-quality genomic DNA from dried seeds.
基金supported bythe Major State Basic Research Development Program ofChina (No. 2004CB117406 and G2000016109)the National Natural Science Foundation of China (No.90208024 and 39823003).
文摘The integration pattern and adjacent host sequences of the inserted pMThGH-transgene in the F4 hGH-transgeniccommon carp were extensively studied. Here we show that each F4 transgenic fish contained about 200 copies of thepMThGH-transgene and the transgenes were integrated into the host genome generally with concatemers in a head-to-tail arrangement at 4-5 insertion sites. By using a method of plasmid rescue, four hundred copies of transgenes fromtwo individuals of F4 transgenic fish, A and B, were recovered and clarified into 6 classes. All classes of recoveredtransgenes contained either complete or partial pMThGH sequences. The class I, which comprised 83% and 84.5%respectively of the recovered transgene copies from fish A and B, had maintained the original configuration, indicatingthat most transgenes were faithfully inherited during the four generations of reproduction. The other five classes weredifferent from the original configuration in both molecular weight and restriction map, indicating that a few transgeneshad undergone mutation, rearrangement or deletion during integration and germline transmission. In the five types ofaberrant transgenes, three flanking sequences of the host genome were analyzed. These sequences were common carpβ-actin gene, common carp DNA sequences homologous to mouse phosphoglycerate kinase-1 and human epidermalkeratin 14, respectively.
基金supported by the National Basic Research Program of China (2013CB329003)the National Natural Science Foundation Program of China (No. 61671179)Funds for Science and Technology on Information Transmission and Dissemination in Communication Networks Laboratory (EX156410046)
文摘To improve the bit error rate(BER) performance of multiple input multiple output(MIMO) systems with low complexity, a three-branch transmission scheme employing 8-weighted-type fractional Fourier transform(8-WFRFT) module is proposed. In the proposed scheme, the original signal is first decomposed into eight sub-signals and then merged into three component signals by the same carrier pattern. The three signals have mathematical constraint relations among themselves that can counteract the channel fading. They are simultaneously transmitted via three independent antennas after delay regulating. At the receiver, an inverse 8-WFRFT module is employed to obtain the estimated original signal by processing the received signal. Then, the bit error rate(BER) performance, transmitting power, transmission rate, power spectrum and computational complexity of the proposed scheme are analysed in detail. Numerical results show that the proposed scheme has a superior performance compared to STBC based three-antenna transmission scheme, in terms of BER performance.
基金supported by the National Natural Science Foundation of China (21476009, 21406007, U1462104)~~
文摘We studied the hydrogenation of 2‐ethylanthraquinone(eAQ) over Pd/SiO2/COR(COR = cordierite) monometallic and Pd‐M/SiO2/COR(M = Ni, Fe, Mn, and Cu) bimetallic monolithic catalysts, which were prepared by the co‐impregnation method. Detailed investigations showed that the particle sizes and structures of the Pd‐M(M = Ni, Fe, Mn, and Cu) bimetallic monolithic catalysts were great‐ly affected by the second metal M and the mass ratio of Pd to the second metal M. By virtue of the small particle size and the strong interaction between Pd and Ni of Pd‐Ni alloy, Pd‐Ni bimetallic monolithic catalysts with the mass ratio of Pd/Ni = 2 achieved the highest H2O2 yield(7.5 g/L) and selectivity(95.3%). Moreover, density functional theory calculations were performed for eAQ ad‐sorption to gain a better mechanistic understanding of the molecule‐surface interactions between eAQ and the Pd(1 1 1) or PdM(1 1 1)(M = Ni, Fe, Mn, and Cu) surfaces. It was found that the high activity of the bimetallic Pd‐Ni catalyst was a result of strong chemisorption between Pd3Ni1(1 1 1) and the carbonyl group of eAQ.
文摘A recombinant plasmid (pcMTsGH) containing the common carp methlothionein promoter (cMT) and salmon growth hormone gene (sGH) was microinjected into common carp fertilized eggs and embryos to optimize the conditions for producing transgenic fish. Several key elements were found to have significant effects on the integration of exogenous gene. These elements include forms and doses of pcMTsGH gene microinjected, stages of embryo at which microinjection conducted and pretreatment of fertilized eggs for microinjection. The results show that, in producing transgenic fish, (1) the best time for microinjection is late onecell stage, (2) the most appropriate dose of pcMTsGH gene for microinjection is around 106~107 copies; (3) the hatching rate rises up when the gene is microinjected into the eggs whose chorions are removed, but the integration rate has no significant changes before and after the removal of egg chorions.
基金Supported by National Natural Science Foundation of China under Grant No.10902083the Natural Science Foundation of Shannxi Province under Grant No.2009GM1007
文摘The effects of Ni coating on the mechanical behaviors of single graphene sheet and their embedded Al matrix composites under axial tension are investigated using molecular dynamics (MD) simulation method. The results show that the Young's moduli and tensile strength of graphene obviously decrease after Ni coating. The results also show that the mechanical properties of Al matrix can be obviously increased by embedding a single graphene sheet. From the simulation, we also find that the Young's modulus and tensile strength of the Ni-coated graphene/Al composite is obviously larger than those of the uncoated graphene/Al composite. The increased magnitude of the Young's modulus and tensile strength of graphene/Al composite are 52.27% and 32.32% at 0.01 K, respectively, due to Ni coating. By exploring the effects of temperature on the mechanical properties of single graphene sheet and their embedded Al matrix composites, it is found that the higher temperature leads to the lower critical strain and tensile strength.
文摘As it is impossible to assume complete rationality in a social dilemma situation, the assumption of bounded rationality is appropriate. Under the bounded rationality, it would be reasonable to assume that one behaves according to the heuristics principle. The group identity effect in a social dilemma situation might be very important in order to attain cooperation. The aim of this study was to clarify how to promote a cooperative behavior by avoiding a social dilemma situation. The group heuristics was taken into account, and it was explored how the group heuristics promotes a cooperative behavior in a social dilemma situation. As a result of a two-person game theory experiment, the group heuristics was found to play an important role in a social dilemma situation, and enhance a cooperative behavior. For the following three cases, the higher cooperation rate was attained at the latter half of the experiment: (a) mutual in-group condition, (b) one-way in-group condition, and (f) one-way unknown condition (in-group). In conclusion, the consciousness of in-group membership might help to promote actively mutual cooperation.
基金Supported by A grant from the University Hospital of Lund(ALF) to Torkel Wadstrm and a grant from the JohnForssman's foundation,the Royal Physiographic Society in Lund to Peren Karagin
文摘AIM:To analyse the possible association of various Helicobacter species and certain common gut bacteria in patients with Meckel's diverticulum and appendicitis.METHODS:A nested-polymerase chain reaction (PCR),specific to 16S rRNA of the Helicobacter genus,was performed on paraffin embedded samples,50 with acute appendicitis,50 normal appendixes,and 33 Meckel's diverticulum with gastric heterotopia and/or ulcer.Helicobacter genus positive samples were sequenced for species identification.All samples were also analysed for certain gut bacteria by PCR.RESULTS:Helicobacter pullorum DNA was found in one out of 33 cases and Enterobacteria in two cases of Meckel's diverticulum.Helicobacter pylori (H.pylori) was found in three,Enterobacter in 18,and Bacteroides in 19 out of 100 appendix samples by PCR.Enterococcus was not found in any MD or appendix samples.All H.pylori positive cases were from normal appendixes.CONCLUSION:Helicobacter is not an etiological agent in the pathogenesis of symptomatic Meckel's diverticulum or in acute appendicitis.
基金Supported by the National Natural Science Foundation of China (No. 90304003)the President Fund of GUCAS (No. O85101HM03).
文摘A new fractal image compression algorithm based on high frequency energy (HFE) partitioning andmatched domain block searching is presented to code synthetic aperture radar (SAR) imagery. In the hybridcoding algorithm, the original SAR image is decomposed to low frequency components and high frequencycomponents by wavelet transform (WT). Then the coder uses HFE of block to partition and searchthe matched domain block for each range block to code the low frequency components. For the high frequencycomponents, a modified embedded zero-tree wavelet coding algorithm is applied. Experiment resultsshow that the proposed coder obtains about 0. 3dB gain when compared to the traditional fractal coderbased on the quadtree partition. Moreover, the subjective visual quality of the reconstructed SAR imageof the proposed coder outperforms that of the traditional fractal coders in the same compression ratio(CR).
文摘With the vigorous development of China' s tourism industry, the rapid expansion of universities and tourism management enrollment has trained a large number of tourism professionals, and promoted the rapid development of tourism. However, the increasing number of colleges and universities tourism management enrollment and the expansion of the tourism industry have not been able to meet the demand for high-class expertise, which partly due to low tourism management teaching quality of colleges and universities. Whereas the school-enterprise cooperation in personnel training mode is one kind of tourism management that can effectively improve the quality of teaching of important measures.
文摘The mathematic model of combined converter with two different flow modes of gas-cooled reactor was established. The effects of gas flow mode in gas-cooled reactor on combined converter was investigated with the yield of methanol was 1 400 kt/a. The results show that if the flow mode of the cooling pipe gas and the catalytic bed gas change from countercurrent to concurrent, the catalytic bed temperature distribution does not fit the most optimum temperature curve of reversible exothermic reaction and the heat duty of heat changer in whole process increased seriously, which means that there is much more equipment investment and more operating cost. The gas flow mode of gas-cooled reactor affects the methanol yield slightly. There- fore, the countercurrent gas flow mode of gas-cooled reactor is more lucrative in the combined converter process.
文摘The framework of digital signature based on qualified certificates and X. 509 architecture is known to have many security risks. Moreover, the fraud prevention mechanism is fragile and does not provide strong guarantees that can be necessary for flow of legal documents. Mediated signatures have been proposed as a mechanism to effectively disable signature cards. In this paper we propose further mechanisms that can be applied on top of mediated RSA, compatible with the standard format, but providing security guarantees even in the case when RSA becomes broken or the keys are compromised. The solution is immune tokleptographic attacks as only deterministic algorithms are used on user's side.
文摘Severe growth abnormalities including shoot stunting, leaf blade reduction and flower bud failure of Brussels sprout were observed in Poland. The presence of phytoplasma in diseased as well as in healthy looking plants, was demonstrated by nested polymerase chain reaction assay employing phytoplasma universal rRNA primer pairs-P1/P7 followed by R16F2n/R16R2. Products of PCR primed by R 16F2n/R 16R2 primer pair from naturally infected Brussels sprouts were sequenced. Comparison of the obtained 16S rDNAs revealed high nucleotide sequence identity between analyzed phytoplasma isolates (99.8%-100%). They were also nearly identical with the sequences of other phytoplasmas isolates from sub-group 16SrI-B, and they were classified as members of "Candidatus Phytoplasma asteris".
文摘The information technology assisted English teaching has witnessed fast development and entered the classroom through course integration process. The integration radically changes the essence of college English teaching, and therefore the traditional teaching mode has been challenged. In other words, information technology has become an integral part in today' s web-based college English teaching classroom. This paper attempts to read in detail about the Boyer' s teaching academic thought. Combined with the current situation of college English teaching, this paper discusses the feasibility of teaching academic thinking is applied to the English network teaching. A model is established by exploratory factor analysis and confirmatory factor analysis. Through the way of questionnaire to the research on the college English network teaching, so as to put forward the solutions and improve the quality of teaching.