In order to forecast projectile impact points quickly and accurately,aprojectile impact point prediction method based on generalized regression neural network（GRNN）is presented.Firstly,the model of GRNN forecasting ...In order to forecast projectile impact points quickly and accurately,aprojectile impact point prediction method based on generalized regression neural network（GRNN）is presented.Firstly,the model of GRNN forecasting impact point is established;secondly,the particle swarm algorithm（PSD）is used to optimize the smooth factor in the prediction model and then the optimal GRNN impact point prediction model is obtained.Finally,the numerical simulation of this prediction model is carried out.Simulation results show that the maximum range error is no more than 40 m,and the lateral deviation error is less than0.2m.The average time of impact point prediction is 6.645 ms,which is 1 300.623 ms less than that of numerical integration method.Therefore,it is feasible and effective for the proposed method to forecast projectile impact points,and thus it can provide a theoretical reference for practical engineering applications.展开更多
Soil microbial biomass and community structures are commonly used as indicators for soil quality and fertility. A investigation was performed to study the effects of long-term natural restoration, cropping, and bare f...Soil microbial biomass and community structures are commonly used as indicators for soil quality and fertility. A investigation was performed to study the effects of long-term natural restoration, cropping, and bare fallow managements on the soil microbial biomass and bacterial community structures in depths of 0-10, 20 30, and 40-50 cm in a black soil （Mollisol）. Microbial biomass was estimated from chloroform fumigation-extraction, and bacterial community structures were determined by analysis of 16S rDNA using polymerase chain reaction-denaturing gradient gel electrophoresis （PCR- DGGE）. Experimental results showed that microbial biomass significantly declined with soil depth in the managements of restoration and cropping, but not in the bare fallow. DGGE profiles indicated that the band number in top 0-10 cm soils was less than that in depth of 20-30 or 40-50 cm. These suggested that the microbial population was high but the bacterial community structure was simple in the topsoil. Cluster and principle component analysis based on DGGE banding patterns showed that the bacterial community structure was affected by soil depth more primarily than by managements, and the succession of bacterial community as increase of soil depth has a similar tendency in the three managements. Fourteen predominating DGGE bands were excised and sequenced, in which 6 bands were identified as the taxa of Verrueomicrobia, 2 bands as Actinobacteria, 2 bands as α-Proteobacteria, and the other 4 bands as 8-Proteobacteria, Aeidobacteria, Nitrospira, and unclassified bacteria. In addition, the sequences of 11 DGGE bands were closely related to uncultured bacteria. Thus, the bacterial community structure in black soil was stable, and the predominating bacterial groups were uncultured.展开更多
A spurious effect of blowing noise is sometimes detected on fans working at high flow rate, showing a large hump around 4000 Hz on the acoustic spectra. A Tollmien-Shlichtling （TS） effect is suspected, and several c...A spurious effect of blowing noise is sometimes detected on fans working at high flow rate, showing a large hump around 4000 Hz on the acoustic spectra. A Tollmien-Shlichtling （TS） effect is suspected, and several compressible LES are made on aerodynamic profiles to detect and investigate this phenomenon. Vortex shedding is observed at the trailing edge, triggering some density fluctuations when a thin boundary layer exists on the profile upper side. Acoustic waves with length equivalent to the chord are observed. A profile modification is proposed with a camber brought closer to the leading edge. This shape tested on a prototyped fan confirms the weakening of the TS effect.展开更多
The predicted increase of temperature by effect of climatic change （1.5 ℃ to 4.5 ℃）, will affect some berry components. Anthocyanins and flavonols concentration are responsible of wine color. The level of anthocya...The predicted increase of temperature by effect of climatic change （1.5 ℃ to 4.5 ℃）, will affect some berry components. Anthocyanins and flavonols concentration are responsible of wine color. The level of anthocyanin is affected by light intensity, temperature, sugars, growth regulators and vineyard management. Abscisic acid （ABA） increases the synthesis of anthocyanin in grape. The object of study was to evaluate the effect of different temperature in berries in vitro, of two cultivars combined with ABA treatments. The treatments were control （C, water） and ABA treatment （1,000 ppm） and temperature： 25, 33 and 40 ℃. In Cabemet Sauvignon, 25 and 33 ~C did not affect anthocyanin total concentration but 40 ℃ produced a 30% decrease in anthocyanin. ABA treatment increased anthocyanin vs. C at 25 and 33 ℃, mainly due to glucosylated forms. But ABA ＋ 40 ℃ showed a 44-60% decrease in all anthocyanins forms compounds. Response of Malbec to the highest temperature （40 ℃）, at the end of ripening, was different; higher temperature produced only slight decrease of total anthocyanins concentration （decrease of 7%）. Combination of temperature ＋ ABA at 20℃ and 33℃ increased anthocyanin. But ABA ＋ 40℃ decreased glucosylated and cumarylated forms of anthocyanin.展开更多
Rhetorical features of Chinese writers’essays have been studied for decades but inconsistent interpretations of deduction and induction lead to controversial results.Taking a comparative rhetoric perspective,this pap...Rhetorical features of Chinese writers’essays have been studied for decades but inconsistent interpretations of deduction and induction lead to controversial results.Taking a comparative rhetoric perspective,this paper clarifies the notions of deduction and induction and investigates what rhetorical features characterize Chinese expository paragraphs besides deduction and induction and whether Chinese EFL learners’English paragraphs have similar features.Two kinds of data sources were used—29 full-score Chinese expositions in College Entrance Examinations and 29 English expositions written by Chinese EFL learners.The results show that deduction is preferred in both Chinese and EFL writing,and that rhetorical paragraphs and coordinate paragraphs are particular to Chinese writing while the EFL learners’paragraphs display hybrid rhetoric such as semi-coordination.It is concluded that neither Chinese paragraphs nor EFL ones are similar to the modern English rhetorical paradigm,and English rhetoric instruction will facilitate the introspection of the two kinds of rhetoric.展开更多
基金Project Funded by Chongqing Changjiang Electrical Appliances Industries Group Co.,Ltd
文摘In order to forecast projectile impact points quickly and accurately,aprojectile impact point prediction method based on generalized regression neural network（GRNN）is presented.Firstly,the model of GRNN forecasting impact point is established;secondly,the particle swarm algorithm（PSD）is used to optimize the smooth factor in the prediction model and then the optimal GRNN impact point prediction model is obtained.Finally,the numerical simulation of this prediction model is carried out.Simulation results show that the maximum range error is no more than 40 m,and the lateral deviation error is less than0.2m.The average time of impact point prediction is 6.645 ms,which is 1 300.623 ms less than that of numerical integration method.Therefore,it is feasible and effective for the proposed method to forecast projectile impact points,and thus it can provide a theoretical reference for practical engineering applications.
基金Project supported by the National Natural Science Foundation of China (No.40671099)
文摘Soil microbial biomass and community structures are commonly used as indicators for soil quality and fertility. A investigation was performed to study the effects of long-term natural restoration, cropping, and bare fallow managements on the soil microbial biomass and bacterial community structures in depths of 0-10, 20 30, and 40-50 cm in a black soil （Mollisol）. Microbial biomass was estimated from chloroform fumigation-extraction, and bacterial community structures were determined by analysis of 16S rDNA using polymerase chain reaction-denaturing gradient gel electrophoresis （PCR- DGGE）. Experimental results showed that microbial biomass significantly declined with soil depth in the managements of restoration and cropping, but not in the bare fallow. DGGE profiles indicated that the band number in top 0-10 cm soils was less than that in depth of 20-30 or 40-50 cm. These suggested that the microbial population was high but the bacterial community structure was simple in the topsoil. Cluster and principle component analysis based on DGGE banding patterns showed that the bacterial community structure was affected by soil depth more primarily than by managements, and the succession of bacterial community as increase of soil depth has a similar tendency in the three managements. Fourteen predominating DGGE bands were excised and sequenced, in which 6 bands were identified as the taxa of Verrueomicrobia, 2 bands as Actinobacteria, 2 bands as α-Proteobacteria, and the other 4 bands as 8-Proteobacteria, Aeidobacteria, Nitrospira, and unclassified bacteria. In addition, the sequences of 11 DGGE bands were closely related to uncultured bacteria. Thus, the bacterial community structure in black soil was stable, and the predominating bacterial groups were uncultured.
文摘A spurious effect of blowing noise is sometimes detected on fans working at high flow rate, showing a large hump around 4000 Hz on the acoustic spectra. A Tollmien-Shlichtling （TS） effect is suspected, and several compressible LES are made on aerodynamic profiles to detect and investigate this phenomenon. Vortex shedding is observed at the trailing edge, triggering some density fluctuations when a thin boundary layer exists on the profile upper side. Acoustic waves with length equivalent to the chord are observed. A profile modification is proposed with a camber brought closer to the leading edge. This shape tested on a prototyped fan confirms the weakening of the TS effect.
文摘The predicted increase of temperature by effect of climatic change （1.5 ℃ to 4.5 ℃）, will affect some berry components. Anthocyanins and flavonols concentration are responsible of wine color. The level of anthocyanin is affected by light intensity, temperature, sugars, growth regulators and vineyard management. Abscisic acid （ABA） increases the synthesis of anthocyanin in grape. The object of study was to evaluate the effect of different temperature in berries in vitro, of two cultivars combined with ABA treatments. The treatments were control （C, water） and ABA treatment （1,000 ppm） and temperature： 25, 33 and 40 ℃. In Cabemet Sauvignon, 25 and 33 ~C did not affect anthocyanin total concentration but 40 ℃ produced a 30% decrease in anthocyanin. ABA treatment increased anthocyanin vs. C at 25 and 33 ℃, mainly due to glucosylated forms. But ABA ＋ 40 ℃ showed a 44-60% decrease in all anthocyanins forms compounds. Response of Malbec to the highest temperature （40 ℃）, at the end of ripening, was different; higher temperature produced only slight decrease of total anthocyanins concentration （decrease of 7%）. Combination of temperature ＋ ABA at 20℃ and 33℃ increased anthocyanin. But ABA ＋ 40℃ decreased glucosylated and cumarylated forms of anthocyanin.
基金supported by the Social Science Department of the Ministry of Education of China[Grant No.:16YJA740022].
文摘Rhetorical features of Chinese writers’essays have been studied for decades but inconsistent interpretations of deduction and induction lead to controversial results.Taking a comparative rhetoric perspective,this paper clarifies the notions of deduction and induction and investigates what rhetorical features characterize Chinese expository paragraphs besides deduction and induction and whether Chinese EFL learners’English paragraphs have similar features.Two kinds of data sources were used—29 full-score Chinese expositions in College Entrance Examinations and 29 English expositions written by Chinese EFL learners.The results show that deduction is preferred in both Chinese and EFL writing,and that rhetorical paragraphs and coordinate paragraphs are particular to Chinese writing while the EFL learners’paragraphs display hybrid rhetoric such as semi-coordination.It is concluded that neither Chinese paragraphs nor EFL ones are similar to the modern English rhetorical paradigm,and English rhetoric instruction will facilitate the introspection of the two kinds of rhetoric.
