[Objective] This study aimed to investigate the correlation between stigma characteristics and outcrossing rate of photo-thermo sensitive genic male sterile(PTGMS) rice lines. [Method] The stigma exsertion rate, sti...[Objective] This study aimed to investigate the correlation between stigma characteristics and outcrossing rate of photo-thermo sensitive genic male sterile(PTGMS) rice lines. [Method] The stigma exsertion rate, stigma size and stigma vitality of Chuang 5S, Yun 9S, Peiai 64 S, P88 S and Y58 S were analyzed. Using R608 as a male parent, outcrossing rate of these five PTGMS lines was determined. [Result]There were differences in stigma exsertion rate, stigma size and stigma vitality among five PTGMS lines. P88 S exhibited the best stigma characteristics and relatively strong stigma vitality, with the stigma exsertion rate of 95.94%, stigma vitality coefficient of 2.71, outcrossing rate of 84.02% in the field. Peiai 64 s had the minimum stigma length(2.41 mm) and stigma width(1.10 mm) and the weakest stigma vitality, with the stigma exsertion rate of 93.04%, outcrossing rate of 65.47%. Yun 9S,Y58 S and Chuang 5S displayed medium stigma characteristics, among which Yun9 S exhibited higher outcrossing rate than other two PTGMS lines. Correlation analysis showed that stigma exsertion rate, stigma length, stigma width, stigma area and stigma volume were significantly correlated to outcrossing rate(P〈0.05), with correlation coefficients of 0.897, 0.934, 0.934, 0.939 and 0.937, respectively. However,there was no significant correlation between stigma vitality coefficient and outcrossing rate. [Conclusion] Based on stigma characteristics of five PTGMS lines, auxiliary pollination measures should be adopted reasonably to save production costs and improve hybrid rice seed yield.展开更多
Four sterile lines (Peiai64S, Y58S, Guangzhan 63-2S and H638S) and the restoring line R527 were used as materials. Five temperature gradients (24, 27, 30, 33 and 36 ℃ in artificial climate chamber) and the natura...Four sterile lines (Peiai64S, Y58S, Guangzhan 63-2S and H638S) and the restoring line R527 were used as materials. Five temperature gradients (24, 27, 30, 33 and 36 ℃ in artificial climate chamber) and the natural temperature (as control) were treated to the four sterile lines for 6 d in the fertility sensitive period of heading to flowering stage, respectively, to study the effects of temperature on physiological biochemical characteristics of young panicles and outcrossing characteristics. The results showed that the percentages of exerted stigma of Peiai 64S and Y58S were the highest at 27 ℃, which were 86.81% and 86.06%, respectively, while the percentages of exerted stigma of Guangzhan 63-2S and H638S were the highest at 24 ℃, which were 76.24% and 81.76%, respectively; the stigma viability of Peiai 64S, Y58S, Guangzhan 63-2S and H638S were the best at 24 ℃, which were 1.96, 2.12, 1.74 and 1.94, respectively; the outcrossing rates of Peiai 64S, Guangzhan 63-2S and H638S were the highest at 24 ℃, which were 58.87%, 54.22% and 50.50%, respectively, while the outcrossing rate of Y58S was the highest at 27 ℃, which was 58.96%; and the contents of peroxidase (POD) of the four sterile lines increased significantly at 33 ℃ compared with the control, while the contents of malondialdehyde (MDA) and proline increased significantly at 36 ℃ compared with the control. There were differences in temperature sensitivity between the male sterile lines, and the 24 ℃ treatment during the sensitive period was the best for the fertility sensitive period of Peiai 64S, while 27 ℃ was the best temperature for Y58S, Gangzhan 63-2S and H638S.展开更多
In this paper,European Center for Medium-Range Weather Forecasts(ECMWF)Reanalysis-Interim(ERAInterim)data and daily precipitation data in China from May to October during 1981-2016 are used to study the climatic chara...In this paper,European Center for Medium-Range Weather Forecasts(ECMWF)Reanalysis-Interim(ERAInterim)data and daily precipitation data in China from May to October during 1981-2016 are used to study the climatic characteristics of the meridionally oriented shear lines(MSLs)over the Tibetan Plateau(TP).The relationship between the MSL and rainstorms in the eastern TP and neighboring areas of the TP during the boreal summer half-year is also investigated.An objective method,which uses a combination of three parameters,i.e.the zonal shear of the meridional wind,the relative vorticity and the zero line of meridional wind,is adopted to identify the shear line.The results show that there are two high-occurrence centers of MSL.One is over the central TP(near 90°E)and the other is over the steep slope area of the eastern TP.Fewer MSLs are found along the Yarlung Zangbo River over the western TP and the southern Tibet.There are averagely 42.2 MSL days in each boreal summer half-year.The number of MSL days reaches the maximum of 62 in 2014 and the minimum of 22 in 2006.July and October witness the maximum of 10.2 MSL days/year and the minimum of 4.2 MSL days/year,respectively.The annual number of the MSL days shows periodicities of 2-4 and 4-6 years,which is quite similar to those of the MSL rainstorm days.In the neighboring areas of the TP,nearly56%of the MSLs lead to rainstorms,and nearly 40%of rainstorms are caused by the MSLs,indicating a close relationship between the MSLs and rainstorms in this region.展开更多
This paper examines initial meso-scale vortex effects on the motion of a tropical cyclone (TC) in a system where coexisting two components of TC and meso-scale vortices with a barotropic vorticity equation model. Th...This paper examines initial meso-scale vortex effects on the motion of a tropical cyclone (TC) in a system where coexisting two components of TC and meso-scale vortices with a barotropic vorticity equation model. The initial mesoscale vortices are generated stochastically by employing Reinaud's method. The 62 simulations are performed and analysed in order to understand the statistical characteristics of the effects. Results show that the deflection of the TC track at t = 24 h induced by the initial meso-scale vortices ranges from 2 km to 37 km with the mean value of 13.4 km. A more significant deflection of the TC track can be reduced when several initial meso-scale vortices simultaneously appear in a smaller TC circulation area. It ranges from 22 km to 37 km with the mean value of 28 km, this fact implies that the initial meso-scale vortices-induced deflection may not be neglected sometimes.展开更多
To solve the coupling effect of multiconductor transmission lines excited by external electromagnetic wave, the modified method of characteristics is proposed. The modified method of characteristics which can compute ...To solve the coupling effect of multiconductor transmission lines excited by external electromagnetic wave, the modified method of characteristics is proposed. The modified method of characteristics which can compute the terminal induced voltages excited by the external electromagnetic wave when the terminal networks or intereonnection networks contain the dynamic elements is introduced. The simulation results indicate that the modified method can analyze the terminal induced voltages when the terminal networks or the interconnection networks contain the dynamic elements excited by the external electromagnetic wave. And the results are compared with the results acquired by FDTD method, the two results are completely same. So one effective modified method is implemented to compute the transmission lines.展开更多
The theory of RC uniform ladder networks based upon the recurrence of voltage and cur-rent functions is extended as a vehicle to analyse the dynamic characteristics of reg lines. Meth-ods for computing the time consta...The theory of RC uniform ladder networks based upon the recurrence of voltage and cur-rent functions is extended as a vehicle to analyse the dynamic characteristics of reg lines. Meth-ods for computing the time constants and simplifying the transfer functions for reg lines are alsopresented.展开更多
This study aimed to investigate chlorophyll content and photosynthetic characteristics of 17 pepper inbred lines which were selected independently. The results showed that chlorophyll contents significantly varied amo...This study aimed to investigate chlorophyll content and photosynthetic characteristics of 17 pepper inbred lines which were selected independently. The results showed that chlorophyll contents significantly varied among different inbred lines. To be specific, chlorophyll content of No. 68 inbred line was significantly higher than that of other 14 inbred lines ; chlorophyll content of No. 55 inbred line was signifieandy lower than that of other 15 inbred lines. The chlorophyll content of various inbred lines showed a decreasing order of No. 68 〉 No. 47 〉 No. 66 〉 No. 62 〉 No. 63 〉 No. 60 〉 No. 61 〉 No. 64 〉 No. 56 〉 No. 67 〉 No. 65 〉 No. 48 〉 No. 59 〉 No. 58 〉 No. 57 〉 No. 69 〉 No. 55 ; the photosynthetic rate of various inbred lines showed a decreasing order of No. 68 〉 No. 57 〉 No. 60 〉 No. 48 〉 No. 58 〉 No. 47 〉 No. 62 〉 No. 63 〉 No. 64 〉 No. 65 ; the maximum photesynthetie rate of No. 65 inbred line was significantly lower than other seven inbred lines, while no signifi- cant difference was observed among other nine inbred lines.展开更多
[Objective] The research aimed to study the meso-scale characteristics of a hail process in Linyi area. [Method] By comprehensively using MICAPS conventional observation data, automatic encryption ground station, MM5 ...[Objective] The research aimed to study the meso-scale characteristics of a hail process in Linyi area. [Method] By comprehensively using MICAPS conventional observation data, automatic encryption ground station, MM5 model product and Doppler weather radar data, a strong convective hail weather process which happened in Shandong Peninsula and southeast of Shandong on May 30, 2010 was analyzed. The circulation background and physical mechanism of strong convection weather occurrence, the features of meso- and micro-scale systems were discussed. Some occurrence and development rules of such weather were found. [Result] The strong convective weather was mainly affected by the cold vortex and translot. The high-altitude northwest airflow, low-level southwest airflow, dry and cold air at the high layer, warm and wet air at the low layer, forward-tilting trough caused the strong convective weather. The radar echo analysis showed that the radar echo in the process belonged to the typical multi-monomer windstorm echo, and the strong echo zone was in the forefront of echo. When the convection development was the strongest, the echo intensity reached 65 dBz, and the echo top height surpassed 11 km. As the development of windstorm monomer, the big-value zone of vertical liquid water content product had the jumping formation and disappearance. Moreover, there was obvious weak echo zone. The windstorm monomer moved to the southeast direction as the precipitation system. In the right front of monomer moving direction, there was hook echo feature. The evolution characteristics of radial speed field at the different elevation angles before and after the hail weather occurrence were analyzed. It was found that the radial speed field had some premonitory variations before the hail weather occurrence. Doppler radar product was used to improve the initial field of MM5 model, which could improve the forecast effect in the certain degree and the accuracy of short-time forecast and nowcasting. [Conclusion] The research accumulated the experience for the short-term forecast and nowcasting work of strong convective weather in future.展开更多
Understanding the unstable evolution of railway slopes is the premise for preventing slope failure and ensuring the safe operation of trains.However,as two major factors affecting the stability of railway slopes,few s...Understanding the unstable evolution of railway slopes is the premise for preventing slope failure and ensuring the safe operation of trains.However,as two major factors affecting the stability of railway slopes,few scholars have explored the unstable evolution of railway slopes under the joint action of rainfall-vibration.Based on the model test of sandy soil slope,the unstable evolution process of slope under locomotive vibration,rainfall,and rainfall-vibration joint action conditions was simulated in this paper.By comparing and analyzing the variation trends of soil pressure and water content of slope under these conditions,the change laws of pore pressure under the influence of vibration and rainfall were explored.The main control factors affecting the stability of slope structure under the joint action conditions were further defined.Combined with the slope failure phenomena under these three conditions,the causes of slope instability resulting from each leading factor were clarified.Finally,according to the above conclusions,the unstable evolution of the slope under the rainfall-vibration joint action was determined.The test results show that the unstable evolution process of sandy soil slope,under the rainfall-vibration joint action,can be divided into:rainfall erosion cracking,vibration promotion penetrating,and slope instability sliding three stages.In the process of slope unstable evolution,rainfall and vibration play the roles of inducing and promoting slide respectively.In addition,the deep cracks,which are the premise for the formation of the sliding surface,and the violent irregular fluctuation of soil pressure,which reflects the near penetration of the sliding surface,constitute the instability characteristics of the railway slope together.This paper reveals the unstable evolution of sandy soil slopes under the joint action of rainfall-vibration,hoping to provide the theoretical basis for the early warning and prevention technology of railway slopes.展开更多
A second rain belt sometimes occurs ahead of a frontal rain belt in the warm sector over coastal South China,leading to heavy precipitation.We examined the differences in the mesoscale characteristics and microphysics...A second rain belt sometimes occurs ahead of a frontal rain belt in the warm sector over coastal South China,leading to heavy precipitation.We examined the differences in the mesoscale characteristics and microphysics of the frontal and warm sector rain belts that occurred in South China on May 10–13,2022.The southern rain belt occurred in an environment with favorable mesoscale conditions but weak large-scale forcing.In contrast,the northern rain belt was related to low-level horizontal shear and the surface-level front.The interaction between the enhanced southeasterly winds and the rainfall-induced cold pool promoted the persistent growth of convection along the southern rain belt.The convective cell propagated east over the coastal area,where there was a large temperature gradient.The bow-shaped echo in this region may be closely related to the rear-inflow jet.By contrast,the initial convection of the northern rain belt was triggered along the front and the region of low-level horizontal shear,with mesoscale interactions between the enhanced warm-moist southeasterly airflow and the cold dome associated with the earlier rain.The terrain blocked the movement of the cold pool,resulting in the stagnation of the frontal convective cell at an early stage.Subsequently,a meso-γ-scale vortex formed during the rapid movement of the convective cell,corresponding to an enhancement of precipitation.The representative raindrop spectra for the southern rain belt were characterized by a greater number and higher density of raindrops than the northern rain belt,even though both resulted in comparable hourly rainfalls.These results help us better understand the characteristics of double rain belts over South China.展开更多
The leaf photosynthesis and nitrogen(N) translocation in three large-spike lines and control cultivar(Xi'nong 979) of winter wheat(Triticum aestivum L.) were studied in 2010–2011 and 2011–2012. The objectives...The leaf photosynthesis and nitrogen(N) translocation in three large-spike lines and control cultivar(Xi'nong 979) of winter wheat(Triticum aestivum L.) were studied in 2010–2011 and 2011–2012. The objectives of this study were to investigate the differences in the physiological characteristics of large-spike lines and control cultivar and identify the limiting factors that play a role in improving the yield of breeding materials. The average yield, grain number per spike, kernel weight per spike, and 1 000-kernel weight of the large-spike lines were 16.0, 26.8, 42.6, and 15.4%, respectively, significantly higher than those of control. The average photosynthetic rates(Pn) were not significant between the large-spike lines and control cultivar during the active growth period. The average PSII maximum energy conversion efficiency(Fv/Fm), PSII actual quantum efficiency(Ф(PSII)), photochemical quenching coefficient(qP), PSII reaction center activity(Fv′/Fm′) and water-use efficiency(WUE) of the large-spike lines were 1.0, 5.1, 3.6, 0.8, and 43.4%, respectively, higher than those of the control during the active growth stages. The N distribution proportions in different tissues were ranked in the order of grains〉culms+sheathes〉rachis+glumes〉flag leaves〉penultimate leaves〉remain leaves. This study suggested that utilization of the large-spike wheat might be a promising approach to obtain higher grain yield in Northwest China.展开更多
On-site monitoring and numerical simulation have been combined to analyze the stability of the jointed surrounding rock and the stress inside the lining structure of a sample deeply buried hydraulic tunnel.We show tha...On-site monitoring and numerical simulation have been combined to analyze the stability of the jointed surrounding rock and the stress inside the lining structure of a sample deeply buried hydraulic tunnel.We show that the deformation around the tunnel was mainly concentrated in the range 51.37 mm∼66.73 mm,the tunnel circumference was dominated by shear failure,and the maximum plastic zone was about 3.90 m.When the shotcrete treatment was performed immediately after the excavation,the deformation of the surrounding rock was reduced by 58.94%∼76.31%,and the extension of the plastic zone was relatively limited,thereby leading to improvements in terms of the stability of surrounding rock.When the support was provided at different time points,the stress of the surrounding rock in the shallow part of the tunnel was improved everywhere.In the tunnel section with high ground stress and joint development,when 10 cm steel fiber concrete spray layer and 40 cm C25 concrete secondary lining were used,the maximum tensile stress on the lining structure was 0.89 MPa,i.e.,it was less than the tensile strength of concrete,which indicates that the internal force of the lining can meet the overall requirements.展开更多
This paper discusses the spatial knowledge related to a line ,and the characteristic points of lines is detected.According to the requirements of line generalization,new algorithms for identifying characteristic line ...This paper discusses the spatial knowledge related to a line ,and the characteristic points of lines is detected.According to the requirements of line generalization,new algorithms for identifying characteristic line points are presented.These characteristic points are used to improve the algorithms of line generalization.An algorithm for identifying bends is shown.In this paper,improved algorithms based on those by Douglas_Peucker,Visvalingam and Whyatt are shown.In this test,the progressive process of line generalization is emphasized.展开更多
The influence of the family of origin is often described in the aetiology of different psychiatric disorders. The majority of papers concerning the families of autistic children concentrate on the quality of their liv...The influence of the family of origin is often described in the aetiology of different psychiatric disorders. The majority of papers concerning the families of autistic children concentrate on the quality of their lives. The aim of our study was to compare the experiences from the family of origin of mothers of children with Autistic Spectrum Disorders (ASD) and from mothers of healthy children. In our study a Family of Origin Scale (FOS) was used. This scale consists of l0 constructs: clarity of expression, responsibility, respect for others, openness to others, acceptance of separation/loss, range of feelings, mood and tone, conflict resolution, empathy and trust. It was a pilot study. The examined group consisted of 9 mothers of children with ASD, the control group-7 mothers of healthy children. We found that both groups differed in a statistically significant way as for the construct called responsibility. Our research was a pilot study and it required further investigations.展开更多
The combining ability and correlation of eight ear characteristics in 99 maize hybrids generated by crossing nine female parents with 11 male parents were analyzed by incomplete diallel cross (NC II ) design. The re...The combining ability and correlation of eight ear characteristics in 99 maize hybrids generated by crossing nine female parents with 11 male parents were analyzed by incomplete diallel cross (NC II ) design. The results showed that the line F6 had the highest general combining ability (GCA) for yield, followed by F7, M3, M4 and M8. All of the five lines have great potential in maize breeding. The cross combination M3xF10 had the highest specific combining ability (SCA) for yield, showing strong heterosis. Heritability analysis of ear characteristics showed that GCA variance was higher than SCA variance in ear diameter, number of rows per ear and seed rate, and they were mainly controlled by the additive gene effect, indicating that that the selections for these traits are effective at early generations. The other three traits had lower SCA, for which the selections should be carried out at late generations. The correlation analysis revealed that ear length, number of grains per row, ear diameter, number of rows per ear, 100-seed weight and seed rate had extremely significant positive correlations with grain yield per plant. Among them, number of grains per row had the most significant effect on yield per plant. Barren tip length had a significant negative correlation with grain yield per plant. Therefore, we concluded that the combinations with more grains per row and shorter barren tip should be selected to achieve high yield of maize.展开更多
[Objective] This study was conducted to screen japonica rice male sterile lines with good flowering characteristics under high temperature and summer drought. [Method] The flowering habits of 23 japonica male sterile ...[Objective] This study was conducted to screen japonica rice male sterile lines with good flowering characteristics under high temperature and summer drought. [Method] The flowering habits of 23 japonica male sterile lines, such as flowering peak, single-panicle flowering duration, single-plant flowering duration, en- closed glume rate, glume-opening angle, the distance between glumes, stigma exer- tion rate and sigma vitality, were compared with II-32A as a control under above weather condition. [Result] The flowering characteristics had significant difference a- mong the tested rice lines. Compared with the control, three japonica rice male ster- ile lines 35478A, 35489A and 35502A had better flowering traits, such as earlier flowering peak, longer single-panicle flowering duration, longer single-plant flowering duration, lower rate of enclosed glumes, larger glume angle and larger distance be- tween glumes. 35478A performed its flowering peak from 10:00-11:00 am, 1.5 h earlier than the control; 35489A exhibited higher stigma exertion rate, up to 76.23%; and 35502A had higher stigma vitality, up to 84.68%, which kept longer time than that of the CK. [Conclusion] The results will provide high-quality resources for the breeding of new japonica rice varieties with high-yield and high-temperature toler- ance.展开更多
By focusing on the vulnerability of the structure of marine equipments, together with considering the randomness of meta-ocean load in statistics, a kind of analytical method of fatigue characteristics of marine struc...By focusing on the vulnerability of the structure of marine equipments, together with considering the randomness of meta-ocean load in statistics, a kind of analytical method of fatigue characteristics of marine structure based on full- scale and actual measurement of prototype is proposed. On the basis of short-term field measurement results of structural response, research is carried out on the fatigue analysis of hinge joints at the upper part of the Soft Yoke single point Mooring System (SYMS) by simultaneously monitoring the environmental load and considering the design criteria of offshore structure. Through analysis of finite element modeling, the time-histories of typical stress response are obtained, and then the assessment of fatigue damage at key hinge joints is conducted. The simulation results indicate that the proposed method can accurately analyze the fatigue damage of offshore engineering structure caused by the effect of wave load. The present analytical method of fatigue characteristics can be extended on other offshore engineering structures subjected to meta-ocean load.展开更多
After the construction of Qinghai-Tibet Highway and Railway, the Qinghai-Tibet Power Transmission(QTPT) line is another major permafrost engineering project with new types of engineering structures. The changing proce...After the construction of Qinghai-Tibet Highway and Railway, the Qinghai-Tibet Power Transmission(QTPT) line is another major permafrost engineering project with new types of engineering structures. The changing process and trend of ground temperature around tower foundations are crucial for the stability of QTPT. We analyzed the change characteristics and tendencies of the ground temperature based on field monitoring data from 2010 to 2014. The results reveal that soil around the tower foundations froze and connected with the artificial permafrost induced during the construction of footings after the first freezing period, and the soil below the original permafrost table kept freezing in subsequent thawing periods. The ground temperature lowered to that of natural fields, fast or slowly for tower foundations with thermosyphons,while for tower foundations without thermosyphons, the increase in ground temperature resulted in higher temperature than that of natural fields. Also, the permafrost temperature and ice content are significant factors that influence the ground temperature around tower foundations. Specifically, the ground temperature around tower foundations in warm and ice-rich permafrost regions decreased slowly, while that in cold and ice poor permafrost regions cooled faster. Moreover, foundations types impacted the ground temperature, which consisted of different technical processes during construction and variant of tower footing structures. The revealed changing process and trend of the ground temperature is beneficial for evaluating the thermal regime evolution around tower foundations in the context of climate change.展开更多
Protein sources in the diet of people living in semi-arid land of Kenya are lacking and if available it is costly to them. In terms of safe food and a healthy food supply, cowpeas (Vigna unguiculata.) are a significan...Protein sources in the diet of people living in semi-arid land of Kenya are lacking and if available it is costly to them. In terms of safe food and a healthy food supply, cowpeas (Vigna unguiculata.) are a significant source of protein, carbohydrates, and minerals especially for poor populations in the Kenya, it is said to be poor man’s meat. The aim of this study was to determine nutritional composition of newly bred ten cowpea lines and five varieties commonly grown in Eastern Kenya of Kitui, Machakos and Makueni counties to understand their potential utilization in curbing rising food and nutrition insecurity in arid and semi-arid lands ASALs and in any other food applications in Kenya. The experiment was arranged in Completely Randomized Design (CRD) whereby proximate composition and minerals were determined using standard AOAC and AACC methods and technological characteristics checked using modified methods used by other researchers. Collected data were subjected to Analysis of Variance (ANOVA) using SAS (2006) version 9.1, mean separation was done using Tukey’s Honestly Significant Difference (HSD) method at 5% level of significance. Cowpeas composition ranged from 12.28% - 13.35% for moisture content, 49.37% - 55.74% for total carbohydrates, 2.99% - 3.34% for crude ash, 0.13% - 0.81% for crude lipids, 23.37% - 29.70% for crude protein and 1.40% - 4.34% for crude fibers. Cowpea samples recorded highest percentage of essential amino acids (60.71%) and non-essential amino acids (39.29%). Minerals ranged from 1.97 - 2.69 mg/100g for calcium, 3.23 - 3.90 mg/100g for magnesium, 205.53 - 223.30 mg/100g for sodium, 0.80 - 1.23 mg/100g for zinc, 1071.15 - 1152.62 mg/100g for potassium and 0.62 - 1.06 mg/100g for phosphorus. For technological properties, lines absorbed water equivalent to their weights and they were comparable to varieties grown in the region. From the results it showed that cowpea line IT97K-1042-3, TEXAN PINKIYE, TX123, IT85F-867-5, IT82D-889-1 and IT82D-889 have desirable attributes such as high crude protein contents, good water absorption capacities and volumetric expansion. They compared well with existing K80 variety. These cowpea lines could possibly be bred and combined into a single cowpea line and further improved by breeders to have other good properties such as higher levels of water absorption during soaking hence reduced cooking times. Therefore, this work has shown that cowpea lines developed can be used as food security crop, industrial food applications and enriching foods of low protein like in complementary foods for healthy food supply in Eastern Kenya.展开更多
Geometric or sub-scale modeling techniques are used for the evaluation of large and complex dynamic structures to ensure accurate reproduction of load path and thus leading to true dynamic characteristics of such stru...Geometric or sub-scale modeling techniques are used for the evaluation of large and complex dynamic structures to ensure accurate reproduction of load path and thus leading to true dynamic characteristics of such structures. The sub-scale modeling technique is very effective in the prediction of vibration characteristics of original large structure when the experimental testing is not feasible due to the absence of a large testing facility. Previous researches were more focused on free and harmonic vibration case with little or no consideration for readily encountered random vibration. A sub-scale modeling technique is proposed for estimating the vibration characteristics of any large scale structure such as Launch vehicles, Mega structures, etc., under various vibration load cases by utilizing precise scaled-down model of that dynamic structure. In order to establish an analytical correlation between the original structure and its scaled models, different scale models of isotropic cantilever beam are selected and analyzed under various vibration conditions( i.e. free, harmonic and random) using finite element package ANSYS. The developed correlations are also validated through experimental testing The prediction made from the vibratory response of the scaled-down beam through the established sets of correlation are found similar to the response measured from the testing of original beam structure. The established correlations are equally applicable in the prediction of dynamic characteristics of any complex structure through its scaled-down models. This paper presents modified sub-scale modeling technique that enables accurate prediction of vibration characteristics of large and complex structure under not only sinusoidal but also for random vibrations.展开更多
基金Supported by National Science and Technology Support Program of China(2014BAD06B07)~~
文摘[Objective] This study aimed to investigate the correlation between stigma characteristics and outcrossing rate of photo-thermo sensitive genic male sterile(PTGMS) rice lines. [Method] The stigma exsertion rate, stigma size and stigma vitality of Chuang 5S, Yun 9S, Peiai 64 S, P88 S and Y58 S were analyzed. Using R608 as a male parent, outcrossing rate of these five PTGMS lines was determined. [Result]There were differences in stigma exsertion rate, stigma size and stigma vitality among five PTGMS lines. P88 S exhibited the best stigma characteristics and relatively strong stigma vitality, with the stigma exsertion rate of 95.94%, stigma vitality coefficient of 2.71, outcrossing rate of 84.02% in the field. Peiai 64 s had the minimum stigma length(2.41 mm) and stigma width(1.10 mm) and the weakest stigma vitality, with the stigma exsertion rate of 93.04%, outcrossing rate of 65.47%. Yun 9S,Y58 S and Chuang 5S displayed medium stigma characteristics, among which Yun9 S exhibited higher outcrossing rate than other two PTGMS lines. Correlation analysis showed that stigma exsertion rate, stigma length, stigma width, stigma area and stigma volume were significantly correlated to outcrossing rate(P〈0.05), with correlation coefficients of 0.897, 0.934, 0.934, 0.939 and 0.937, respectively. However,there was no significant correlation between stigma vitality coefficient and outcrossing rate. [Conclusion] Based on stigma characteristics of five PTGMS lines, auxiliary pollination measures should be adopted reasonably to save production costs and improve hybrid rice seed yield.
基金Supported by the National Science-technology Support Plan Project(2014BAD06B07)the Agricultural Special Fund of the Department of Finance of Hunan Provincethe Innovation Project of Hunan Province(XCX15148)~~
文摘Four sterile lines (Peiai64S, Y58S, Guangzhan 63-2S and H638S) and the restoring line R527 were used as materials. Five temperature gradients (24, 27, 30, 33 and 36 ℃ in artificial climate chamber) and the natural temperature (as control) were treated to the four sterile lines for 6 d in the fertility sensitive period of heading to flowering stage, respectively, to study the effects of temperature on physiological biochemical characteristics of young panicles and outcrossing characteristics. The results showed that the percentages of exerted stigma of Peiai 64S and Y58S were the highest at 27 ℃, which were 86.81% and 86.06%, respectively, while the percentages of exerted stigma of Guangzhan 63-2S and H638S were the highest at 24 ℃, which were 76.24% and 81.76%, respectively; the stigma viability of Peiai 64S, Y58S, Guangzhan 63-2S and H638S were the best at 24 ℃, which were 1.96, 2.12, 1.74 and 1.94, respectively; the outcrossing rates of Peiai 64S, Guangzhan 63-2S and H638S were the highest at 24 ℃, which were 58.87%, 54.22% and 50.50%, respectively, while the outcrossing rate of Y58S was the highest at 27 ℃, which was 58.96%; and the contents of peroxidase (POD) of the four sterile lines increased significantly at 33 ℃ compared with the control, while the contents of malondialdehyde (MDA) and proline increased significantly at 36 ℃ compared with the control. There were differences in temperature sensitivity between the male sterile lines, and the 24 ℃ treatment during the sensitive period was the best for the fertility sensitive period of Peiai 64S, while 27 ℃ was the best temperature for Y58S, Gangzhan 63-2S and H638S.
基金National Key R&D Program of China(2018YFC1507804)National Natural Science Foundation of China(91937301,41775048,91637105)Second Tibetan Plateau Scientific Expedition and Research(STEP)Program(2019QZKK0105)
文摘In this paper,European Center for Medium-Range Weather Forecasts(ECMWF)Reanalysis-Interim(ERAInterim)data and daily precipitation data in China from May to October during 1981-2016 are used to study the climatic characteristics of the meridionally oriented shear lines(MSLs)over the Tibetan Plateau(TP).The relationship between the MSL and rainstorms in the eastern TP and neighboring areas of the TP during the boreal summer half-year is also investigated.An objective method,which uses a combination of three parameters,i.e.the zonal shear of the meridional wind,the relative vorticity and the zero line of meridional wind,is adopted to identify the shear line.The results show that there are two high-occurrence centers of MSL.One is over the central TP(near 90°E)and the other is over the steep slope area of the eastern TP.Fewer MSLs are found along the Yarlung Zangbo River over the western TP and the southern Tibet.There are averagely 42.2 MSL days in each boreal summer half-year.The number of MSL days reaches the maximum of 62 in 2014 and the minimum of 22 in 2006.July and October witness the maximum of 10.2 MSL days/year and the minimum of 4.2 MSL days/year,respectively.The annual number of the MSL days shows periodicities of 2-4 and 4-6 years,which is quite similar to those of the MSL rainstorm days.In the neighboring areas of the TP,nearly56%of the MSLs lead to rainstorms,and nearly 40%of rainstorms are caused by the MSLs,indicating a close relationship between the MSLs and rainstorms in this region.
基金supported by the National Natural Science Foundation of China (Grant Nos. 40775038,40875031 and 40975036)the Science Foundation of Wuxi Environment Science and Technology Research Center
文摘This paper examines initial meso-scale vortex effects on the motion of a tropical cyclone (TC) in a system where coexisting two components of TC and meso-scale vortices with a barotropic vorticity equation model. The initial mesoscale vortices are generated stochastically by employing Reinaud's method. The 62 simulations are performed and analysed in order to understand the statistical characteristics of the effects. Results show that the deflection of the TC track at t = 24 h induced by the initial meso-scale vortices ranges from 2 km to 37 km with the mean value of 13.4 km. A more significant deflection of the TC track can be reduced when several initial meso-scale vortices simultaneously appear in a smaller TC circulation area. It ranges from 22 km to 37 km with the mean value of 28 km, this fact implies that the initial meso-scale vortices-induced deflection may not be neglected sometimes.
文摘To solve the coupling effect of multiconductor transmission lines excited by external electromagnetic wave, the modified method of characteristics is proposed. The modified method of characteristics which can compute the terminal induced voltages excited by the external electromagnetic wave when the terminal networks or intereonnection networks contain the dynamic elements is introduced. The simulation results indicate that the modified method can analyze the terminal induced voltages when the terminal networks or the interconnection networks contain the dynamic elements excited by the external electromagnetic wave. And the results are compared with the results acquired by FDTD method, the two results are completely same. So one effective modified method is implemented to compute the transmission lines.
文摘The theory of RC uniform ladder networks based upon the recurrence of voltage and cur-rent functions is extended as a vehicle to analyse the dynamic characteristics of reg lines. Meth-ods for computing the time constants and simplifying the transfer functions for reg lines are alsopresented.
基金Supported by vegetable Station of Ningxia Hui Autonomous Region
文摘This study aimed to investigate chlorophyll content and photosynthetic characteristics of 17 pepper inbred lines which were selected independently. The results showed that chlorophyll contents significantly varied among different inbred lines. To be specific, chlorophyll content of No. 68 inbred line was significantly higher than that of other 14 inbred lines ; chlorophyll content of No. 55 inbred line was signifieandy lower than that of other 15 inbred lines. The chlorophyll content of various inbred lines showed a decreasing order of No. 68 〉 No. 47 〉 No. 66 〉 No. 62 〉 No. 63 〉 No. 60 〉 No. 61 〉 No. 64 〉 No. 56 〉 No. 67 〉 No. 65 〉 No. 48 〉 No. 59 〉 No. 58 〉 No. 57 〉 No. 69 〉 No. 55 ; the photosynthetic rate of various inbred lines showed a decreasing order of No. 68 〉 No. 57 〉 No. 60 〉 No. 48 〉 No. 58 〉 No. 47 〉 No. 62 〉 No. 63 〉 No. 64 〉 No. 65 ; the maximum photesynthetie rate of No. 65 inbred line was significantly lower than other seven inbred lines, while no signifi- cant difference was observed among other nine inbred lines.
文摘[Objective] The research aimed to study the meso-scale characteristics of a hail process in Linyi area. [Method] By comprehensively using MICAPS conventional observation data, automatic encryption ground station, MM5 model product and Doppler weather radar data, a strong convective hail weather process which happened in Shandong Peninsula and southeast of Shandong on May 30, 2010 was analyzed. The circulation background and physical mechanism of strong convection weather occurrence, the features of meso- and micro-scale systems were discussed. Some occurrence and development rules of such weather were found. [Result] The strong convective weather was mainly affected by the cold vortex and translot. The high-altitude northwest airflow, low-level southwest airflow, dry and cold air at the high layer, warm and wet air at the low layer, forward-tilting trough caused the strong convective weather. The radar echo analysis showed that the radar echo in the process belonged to the typical multi-monomer windstorm echo, and the strong echo zone was in the forefront of echo. When the convection development was the strongest, the echo intensity reached 65 dBz, and the echo top height surpassed 11 km. As the development of windstorm monomer, the big-value zone of vertical liquid water content product had the jumping formation and disappearance. Moreover, there was obvious weak echo zone. The windstorm monomer moved to the southeast direction as the precipitation system. In the right front of monomer moving direction, there was hook echo feature. The evolution characteristics of radial speed field at the different elevation angles before and after the hail weather occurrence were analyzed. It was found that the radial speed field had some premonitory variations before the hail weather occurrence. Doppler radar product was used to improve the initial field of MM5 model, which could improve the forecast effect in the certain degree and the accuracy of short-time forecast and nowcasting. [Conclusion] The research accumulated the experience for the short-term forecast and nowcasting work of strong convective weather in future.
基金supported by the Major Research Plan of the National Natural Science Foundation of China(Grant No.42027806)the Key Programme of the Natural Science Foundation of China(Grant No.41630639)National Natural Science Foundation of China General Program(Grant No.42372324).
文摘Understanding the unstable evolution of railway slopes is the premise for preventing slope failure and ensuring the safe operation of trains.However,as two major factors affecting the stability of railway slopes,few scholars have explored the unstable evolution of railway slopes under the joint action of rainfall-vibration.Based on the model test of sandy soil slope,the unstable evolution process of slope under locomotive vibration,rainfall,and rainfall-vibration joint action conditions was simulated in this paper.By comparing and analyzing the variation trends of soil pressure and water content of slope under these conditions,the change laws of pore pressure under the influence of vibration and rainfall were explored.The main control factors affecting the stability of slope structure under the joint action conditions were further defined.Combined with the slope failure phenomena under these three conditions,the causes of slope instability resulting from each leading factor were clarified.Finally,according to the above conclusions,the unstable evolution of the slope under the rainfall-vibration joint action was determined.The test results show that the unstable evolution process of sandy soil slope,under the rainfall-vibration joint action,can be divided into:rainfall erosion cracking,vibration promotion penetrating,and slope instability sliding three stages.In the process of slope unstable evolution,rainfall and vibration play the roles of inducing and promoting slide respectively.In addition,the deep cracks,which are the premise for the formation of the sliding surface,and the violent irregular fluctuation of soil pressure,which reflects the near penetration of the sliding surface,constitute the instability characteristics of the railway slope together.This paper reveals the unstable evolution of sandy soil slopes under the joint action of rainfall-vibration,hoping to provide the theoretical basis for the early warning and prevention technology of railway slopes.
基金National Natural Science Foundation of China(41930972,52239006,41975001)。
文摘A second rain belt sometimes occurs ahead of a frontal rain belt in the warm sector over coastal South China,leading to heavy precipitation.We examined the differences in the mesoscale characteristics and microphysics of the frontal and warm sector rain belts that occurred in South China on May 10–13,2022.The southern rain belt occurred in an environment with favorable mesoscale conditions but weak large-scale forcing.In contrast,the northern rain belt was related to low-level horizontal shear and the surface-level front.The interaction between the enhanced southeasterly winds and the rainfall-induced cold pool promoted the persistent growth of convection along the southern rain belt.The convective cell propagated east over the coastal area,where there was a large temperature gradient.The bow-shaped echo in this region may be closely related to the rear-inflow jet.By contrast,the initial convection of the northern rain belt was triggered along the front and the region of low-level horizontal shear,with mesoscale interactions between the enhanced warm-moist southeasterly airflow and the cold dome associated with the earlier rain.The terrain blocked the movement of the cold pool,resulting in the stagnation of the frontal convective cell at an early stage.Subsequently,a meso-γ-scale vortex formed during the rapid movement of the convective cell,corresponding to an enhancement of precipitation.The representative raindrop spectra for the southern rain belt were characterized by a greater number and higher density of raindrops than the northern rain belt,even though both resulted in comparable hourly rainfalls.These results help us better understand the characteristics of double rain belts over South China.
基金financially supported by the National Natural Science Foundation of China (31370425, 31501276)the Key Technologies R&D Program of China during the 12th Five-Year Plan period (2015BAD22B01)
文摘The leaf photosynthesis and nitrogen(N) translocation in three large-spike lines and control cultivar(Xi'nong 979) of winter wheat(Triticum aestivum L.) were studied in 2010–2011 and 2011–2012. The objectives of this study were to investigate the differences in the physiological characteristics of large-spike lines and control cultivar and identify the limiting factors that play a role in improving the yield of breeding materials. The average yield, grain number per spike, kernel weight per spike, and 1 000-kernel weight of the large-spike lines were 16.0, 26.8, 42.6, and 15.4%, respectively, significantly higher than those of control. The average photosynthetic rates(Pn) were not significant between the large-spike lines and control cultivar during the active growth period. The average PSII maximum energy conversion efficiency(Fv/Fm), PSII actual quantum efficiency(Ф(PSII)), photochemical quenching coefficient(qP), PSII reaction center activity(Fv′/Fm′) and water-use efficiency(WUE) of the large-spike lines were 1.0, 5.1, 3.6, 0.8, and 43.4%, respectively, higher than those of the control during the active growth stages. The N distribution proportions in different tissues were ranked in the order of grains〉culms+sheathes〉rachis+glumes〉flag leaves〉penultimate leaves〉remain leaves. This study suggested that utilization of the large-spike wheat might be a promising approach to obtain higher grain yield in Northwest China.
基金This work was financially supported by the National Natural Science Foundation of China(Grant No.51769031)Regional Innovation Guidance Plan Project of the XPCC(Grant No.2021BB004).
文摘On-site monitoring and numerical simulation have been combined to analyze the stability of the jointed surrounding rock and the stress inside the lining structure of a sample deeply buried hydraulic tunnel.We show that the deformation around the tunnel was mainly concentrated in the range 51.37 mm∼66.73 mm,the tunnel circumference was dominated by shear failure,and the maximum plastic zone was about 3.90 m.When the shotcrete treatment was performed immediately after the excavation,the deformation of the surrounding rock was reduced by 58.94%∼76.31%,and the extension of the plastic zone was relatively limited,thereby leading to improvements in terms of the stability of surrounding rock.When the support was provided at different time points,the stress of the surrounding rock in the shallow part of the tunnel was improved everywhere.In the tunnel section with high ground stress and joint development,when 10 cm steel fiber concrete spray layer and 40 cm C25 concrete secondary lining were used,the maximum tensile stress on the lining structure was 0.89 MPa,i.e.,it was less than the tensile strength of concrete,which indicates that the internal force of the lining can meet the overall requirements.
文摘This paper discusses the spatial knowledge related to a line ,and the characteristic points of lines is detected.According to the requirements of line generalization,new algorithms for identifying characteristic line points are presented.These characteristic points are used to improve the algorithms of line generalization.An algorithm for identifying bends is shown.In this paper,improved algorithms based on those by Douglas_Peucker,Visvalingam and Whyatt are shown.In this test,the progressive process of line generalization is emphasized.
文摘The influence of the family of origin is often described in the aetiology of different psychiatric disorders. The majority of papers concerning the families of autistic children concentrate on the quality of their lives. The aim of our study was to compare the experiences from the family of origin of mothers of children with Autistic Spectrum Disorders (ASD) and from mothers of healthy children. In our study a Family of Origin Scale (FOS) was used. This scale consists of l0 constructs: clarity of expression, responsibility, respect for others, openness to others, acceptance of separation/loss, range of feelings, mood and tone, conflict resolution, empathy and trust. It was a pilot study. The examined group consisted of 9 mothers of children with ASD, the control group-7 mothers of healthy children. We found that both groups differed in a statistically significant way as for the construct called responsibility. Our research was a pilot study and it required further investigations.
文摘The combining ability and correlation of eight ear characteristics in 99 maize hybrids generated by crossing nine female parents with 11 male parents were analyzed by incomplete diallel cross (NC II ) design. The results showed that the line F6 had the highest general combining ability (GCA) for yield, followed by F7, M3, M4 and M8. All of the five lines have great potential in maize breeding. The cross combination M3xF10 had the highest specific combining ability (SCA) for yield, showing strong heterosis. Heritability analysis of ear characteristics showed that GCA variance was higher than SCA variance in ear diameter, number of rows per ear and seed rate, and they were mainly controlled by the additive gene effect, indicating that that the selections for these traits are effective at early generations. The other three traits had lower SCA, for which the selections should be carried out at late generations. The correlation analysis revealed that ear length, number of grains per row, ear diameter, number of rows per ear, 100-seed weight and seed rate had extremely significant positive correlations with grain yield per plant. Among them, number of grains per row had the most significant effect on yield per plant. Barren tip length had a significant negative correlation with grain yield per plant. Therefore, we concluded that the combinations with more grains per row and shorter barren tip should be selected to achieve high yield of maize.
基金Supported by Scientific and Technological Talents Program of Chongqing(cstc2013kjrcqnrc80002)Key Science and Technology Research and Development Program of Chongqing(cstc2012gg B80005,cstc2012gg C80002)the Fund from Chongqing Academy of Agricultural Sciences for Agricultural Development(NKY,2013AC008)~~
文摘[Objective] This study was conducted to screen japonica rice male sterile lines with good flowering characteristics under high temperature and summer drought. [Method] The flowering habits of 23 japonica male sterile lines, such as flowering peak, single-panicle flowering duration, single-plant flowering duration, en- closed glume rate, glume-opening angle, the distance between glumes, stigma exer- tion rate and sigma vitality, were compared with II-32A as a control under above weather condition. [Result] The flowering characteristics had significant difference a- mong the tested rice lines. Compared with the control, three japonica rice male ster- ile lines 35478A, 35489A and 35502A had better flowering traits, such as earlier flowering peak, longer single-panicle flowering duration, longer single-plant flowering duration, lower rate of enclosed glumes, larger glume angle and larger distance be- tween glumes. 35478A performed its flowering peak from 10:00-11:00 am, 1.5 h earlier than the control; 35489A exhibited higher stigma exertion rate, up to 76.23%; and 35502A had higher stigma vitality, up to 84.68%, which kept longer time than that of the CK. [Conclusion] The results will provide high-quality resources for the breeding of new japonica rice varieties with high-yield and high-temperature toler- ance.
基金financially supported by the National Natural Science Foundation of China(Grant No.15572072)the National Key Basic Research and Development Program(Grant Nos.2014CB046803 and 2016ZX05028-002-005)
文摘By focusing on the vulnerability of the structure of marine equipments, together with considering the randomness of meta-ocean load in statistics, a kind of analytical method of fatigue characteristics of marine structure based on full- scale and actual measurement of prototype is proposed. On the basis of short-term field measurement results of structural response, research is carried out on the fatigue analysis of hinge joints at the upper part of the Soft Yoke single point Mooring System (SYMS) by simultaneously monitoring the environmental load and considering the design criteria of offshore structure. Through analysis of finite element modeling, the time-histories of typical stress response are obtained, and then the assessment of fatigue damage at key hinge joints is conducted. The simulation results indicate that the proposed method can accurately analyze the fatigue damage of offshore engineering structure caused by the effect of wave load. The present analytical method of fatigue characteristics can be extended on other offshore engineering structures subjected to meta-ocean load.
基金supported by National Natural Science Fund of China (Grant No. 41401088)State Grid Qinghai Electric Power Research Institute (SGQHDKYOSBJS201600077, SGQHDKYOSBJS 1700068)Funds of State Key Laboratory of Frozen Soil Engineering (Nos. SKLFSE-ZY-17, SKLFSEZT-32)
文摘After the construction of Qinghai-Tibet Highway and Railway, the Qinghai-Tibet Power Transmission(QTPT) line is another major permafrost engineering project with new types of engineering structures. The changing process and trend of ground temperature around tower foundations are crucial for the stability of QTPT. We analyzed the change characteristics and tendencies of the ground temperature based on field monitoring data from 2010 to 2014. The results reveal that soil around the tower foundations froze and connected with the artificial permafrost induced during the construction of footings after the first freezing period, and the soil below the original permafrost table kept freezing in subsequent thawing periods. The ground temperature lowered to that of natural fields, fast or slowly for tower foundations with thermosyphons,while for tower foundations without thermosyphons, the increase in ground temperature resulted in higher temperature than that of natural fields. Also, the permafrost temperature and ice content are significant factors that influence the ground temperature around tower foundations. Specifically, the ground temperature around tower foundations in warm and ice-rich permafrost regions decreased slowly, while that in cold and ice poor permafrost regions cooled faster. Moreover, foundations types impacted the ground temperature, which consisted of different technical processes during construction and variant of tower footing structures. The revealed changing process and trend of the ground temperature is beneficial for evaluating the thermal regime evolution around tower foundations in the context of climate change.
文摘Protein sources in the diet of people living in semi-arid land of Kenya are lacking and if available it is costly to them. In terms of safe food and a healthy food supply, cowpeas (Vigna unguiculata.) are a significant source of protein, carbohydrates, and minerals especially for poor populations in the Kenya, it is said to be poor man’s meat. The aim of this study was to determine nutritional composition of newly bred ten cowpea lines and five varieties commonly grown in Eastern Kenya of Kitui, Machakos and Makueni counties to understand their potential utilization in curbing rising food and nutrition insecurity in arid and semi-arid lands ASALs and in any other food applications in Kenya. The experiment was arranged in Completely Randomized Design (CRD) whereby proximate composition and minerals were determined using standard AOAC and AACC methods and technological characteristics checked using modified methods used by other researchers. Collected data were subjected to Analysis of Variance (ANOVA) using SAS (2006) version 9.1, mean separation was done using Tukey’s Honestly Significant Difference (HSD) method at 5% level of significance. Cowpeas composition ranged from 12.28% - 13.35% for moisture content, 49.37% - 55.74% for total carbohydrates, 2.99% - 3.34% for crude ash, 0.13% - 0.81% for crude lipids, 23.37% - 29.70% for crude protein and 1.40% - 4.34% for crude fibers. Cowpea samples recorded highest percentage of essential amino acids (60.71%) and non-essential amino acids (39.29%). Minerals ranged from 1.97 - 2.69 mg/100g for calcium, 3.23 - 3.90 mg/100g for magnesium, 205.53 - 223.30 mg/100g for sodium, 0.80 - 1.23 mg/100g for zinc, 1071.15 - 1152.62 mg/100g for potassium and 0.62 - 1.06 mg/100g for phosphorus. For technological properties, lines absorbed water equivalent to their weights and they were comparable to varieties grown in the region. From the results it showed that cowpea line IT97K-1042-3, TEXAN PINKIYE, TX123, IT85F-867-5, IT82D-889-1 and IT82D-889 have desirable attributes such as high crude protein contents, good water absorption capacities and volumetric expansion. They compared well with existing K80 variety. These cowpea lines could possibly be bred and combined into a single cowpea line and further improved by breeders to have other good properties such as higher levels of water absorption during soaking hence reduced cooking times. Therefore, this work has shown that cowpea lines developed can be used as food security crop, industrial food applications and enriching foods of low protein like in complementary foods for healthy food supply in Eastern Kenya.
文摘Geometric or sub-scale modeling techniques are used for the evaluation of large and complex dynamic structures to ensure accurate reproduction of load path and thus leading to true dynamic characteristics of such structures. The sub-scale modeling technique is very effective in the prediction of vibration characteristics of original large structure when the experimental testing is not feasible due to the absence of a large testing facility. Previous researches were more focused on free and harmonic vibration case with little or no consideration for readily encountered random vibration. A sub-scale modeling technique is proposed for estimating the vibration characteristics of any large scale structure such as Launch vehicles, Mega structures, etc., under various vibration load cases by utilizing precise scaled-down model of that dynamic structure. In order to establish an analytical correlation between the original structure and its scaled models, different scale models of isotropic cantilever beam are selected and analyzed under various vibration conditions( i.e. free, harmonic and random) using finite element package ANSYS. The developed correlations are also validated through experimental testing The prediction made from the vibratory response of the scaled-down beam through the established sets of correlation are found similar to the response measured from the testing of original beam structure. The established correlations are equally applicable in the prediction of dynamic characteristics of any complex structure through its scaled-down models. This paper presents modified sub-scale modeling technique that enables accurate prediction of vibration characteristics of large and complex structure under not only sinusoidal but also for random vibrations.