Background:In bird species where offspring growth and survival rely on parents’food provisioning,parents can maximise their fitness by increasing the quantity and/or the quality of preys delivered to their offspring....Background:In bird species where offspring growth and survival rely on parents’food provisioning,parents can maximise their fitness by increasing the quantity and/or the quality of preys delivered to their offspring.Many studies have focused on inter-individual variation in feeding rate,yet this measure may not accurately reflect the total amount of food(i.e.energy)provided by parents if there is large variation in the quantity and quality of preys at each feeding.Here,we explored the relative role of individual(sex,age,body condition),breeding(hatching date,brood size)and environmental(temperature)factors on feeding rate,prey number,size and quality,and their contribution to total prey biomass delivered to the nestlings of 164 Collared Flycatcher(Ficedula albicollis)parents in 98 nests.Results:Preys delivered to the nest were mainly larvae(53.6%)and flying insects(45.6%).Feeding rate increased with brood size and age,and was higher in males than females.Mean prey number decreased,but mean prey size increased,as the season progressed and parents feeding their brood with primary larvae brought more preys per visit.Relationships between feeding rate,mean prey number and size remained when taking into account the provision-ing quality:parents brought either a large number of small prey or a small number of larger items,and the force of the trade-offs between feeding rate and mean prey number and size depended on the quality of the provisioning of the parents.Whatever the percentage of larvae among preys in the provisioning,the variance in total prey biomass was foremost explained by feeding rate(65.1%to 76.6%)compared to mean prey number(16.4%to 26%)and prey size(2.7%to 4%).Conclusions:Our study shows that variation in feeding rate,prey number,size,but not quality(i.e.percentage of lar-vae),were influenced by individual factors(sex and age)and breeding decisions(brood size and timing of breeding)and that,whatever the provisioning strategy adopted,feeding rate was the best proxy of the total biomass delivered to the nestlings.展开更多
The trade creation and conservation of wild species in Amazon, including collared peccaries （Pecari tajacu）, may be favored by artificial insemination, but the time of semen storage may lead to reduced fertility in ...The trade creation and conservation of wild species in Amazon, including collared peccaries （Pecari tajacu）, may be favored by artificial insemination, but the time of semen storage may lead to reduced fertility in sperm of some wild animals. Thus, the aim of this research was to evaluate the influence of semen storage at 17 ℃ over time on seminal features of peccaries in captivity. Eight adult males were sedated and underwent electroejaculation. The ejaculates （n = 65） were evaluated for volume, concentration, pH, sperm motility, vigor, and cell with intact plasma membrane intact （IPM） and sperm morphology. Selected ejaculates （n = 21） were diluted （1：1） in Beltsville Thawing Solution and kept during 48 hours under controlled temperature （17 ℃）. Assessments were made after dilution （TO）, after 24 hours （T24）, and 48 hours after the onset of cooling （T48）. The storage impacted on sperm survival （P 〈 0.05）. Semen characteristics changed throughout the storage period studied and after 48 hours storage. The decline of sperm motility was of 55.2% for 10.9%, vigor was 2.3 for 0.5 and IPM cells were of 59.0% for 15.8%. Primary defects sperm increased of 19.8% for 32.2%, secondary defects of 9.8% for 10.4% and total defects of 29.4% for 42.7%. However, within 24 hours of preservation, chilled semen peccaries presented sperm motility average rate and IMP cells levels indicative to use in assisted reproductive events. These results indicate chilled semen for 24 hours could be used in experimentally artificial insemination of peccaries, technology that still has not been performed before.展开更多
Background:Eurasian Collared Dove(Streptopelia decaocto)is a species distributed in the Eurasian continent and North Africa,and inhabiting mainly in Saitama Prefecture in Japan.Eurasian Collared Dove is one of the mos...Background:Eurasian Collared Dove(Streptopelia decaocto)is a species distributed in the Eurasian continent and North Africa,and inhabiting mainly in Saitama Prefecture in Japan.Eurasian Collared Dove is one of the most prosper-ous invaders in the world,and Japanese Eurasian Collared Dove has also been introduced from overseas.The Japa-nese population has declined to one-hundredth over 30 years and is being protected.In this study,we analyzed its genetic diversity in order to understand the genetic differences between wild populations of Eurasian Collared Dove and those bred in zoos.Methods:A sequence of about 1.9 kb mtDNA was determined for 20 wild Eurasian Collared Doves living in Saitama,Japan and 20 zoo-bred Eurasian Collared Doves,and population genetic analysis was performed.Results:In the COI gene,778 bp had the same sequence in all the 40 individuals examined,and no mutation sites could be confirmed.In the control region,two base substitution sites were confirmed in 1140 bp long sequence.Three haplotypes were detected in 20 individuals in wild,whereas all 20 zoo-bred individuals possessed the same haplotypes possessed in the wild population.Conclusion:Haplotypes of zoo-bred individuals were also retained among the wild individuals,confirming that no genetic problems could occur if the zoo-bred individuals were released to the wild for the Japanese Eurasian Collared Dove propagation program.展开更多
Many tree planting programmes have long been initiated to increase forest cover to mitigate the effects of global climate change.Successful planting requires careful planning at the project level,including using suita...Many tree planting programmes have long been initiated to increase forest cover to mitigate the effects of global climate change.Successful planting requires careful planning at the project level,including using suitable species with favourable traits.However,there is a paucity of improvement data for tropical tree species.An experimental common garden of Shorea leprosula was established to study traits related to growth performance which are key factors in planting success.Seedlings of S.leprosula were collected from nine geographical forest reserves.To study the effects of genetic variation,seedlings were planted in a common environment following a randomized complete block design.From performance data collected 2017‒2019,one population showed the highest coefficient for relative height growth,significantly higher than most of the other populations.Interestingly,this population from Beserah also exhibited the lowest coefficient for scale insect infestation.This study provides preliminary results on growth performance and susceptibility to scale insect infestation in S.leprosula and the first common garden experiment site conducted on dipterocarp species.It lays a foundation for future genome-wide studies.展开更多
Collar rot caused the death of Hevea rubber in a village located in Jino County of Xishuangbanna in September, 2012. In order to elucidate the causal agent of collar rot and its taxonomic status, the causal fungus was...Collar rot caused the death of Hevea rubber in a village located in Jino County of Xishuangbanna in September, 2012. In order to elucidate the causal agent of collar rot and its taxonomic status, the causal fungus was isolated and identified through a series of tests about its pathogenicity, morphology, culture feature and biological characteristics. The results indicated that the fungus was Fusarium venfrico- sum. It could grow at temperatures ranging from 10 to 40 ℃, and the most suitable temperature was 30 ℃. Its mycelium growth was inhibited above 40 ℃ or below 10 ℃. The accumulated water in wet season was the main reason for this disease occurrence.展开更多
A study was conducted to detect the effect of water extracts from different parts such as root, bark, branch and leaf, of adult larch, Larix gmelini, trees on growth of Manchurian walnut, Juglans mandshudca, seedlings...A study was conducted to detect the effect of water extracts from different parts such as root, bark, branch and leaf, of adult larch, Larix gmelini, trees on growth of Manchurian walnut, Juglans mandshudca, seedlings and the allelopathy between the two tree species. Four concentrations （100 g. kg i, 50 g. kg^-1, 25 g. kg^-1 and 12.5 g. kg^-1） were prepared for each kind of extracts. Result showed that the water extracts with low and moderate concentrations accelerated the growth of collar diameter and increased biomass and root/shoot ratio of walnut seedlings. The water extracts from branches and barks with low and moderate concentrations accelerated the height growth of the seedlings, while those from leaves and roots slightly decreased the height growth of seedlings. The fact that application of water extracts of larch improved the growth of Manchurian walnut attributes possibly to the allelopathy between the two tree species.展开更多
Rockbolt is widely employed all over the world as an effective ground reinforcement element in order to secure the underground workplaces.Ordinary encapsulated rebar or rebar rockbolt is most popular and commonly used...Rockbolt is widely employed all over the world as an effective ground reinforcement element in order to secure the underground workplaces.Ordinary encapsulated rebar or rebar rockbolt is most popular and commonly used as reinforcement in a ground support system because of its accessibility,cost effectiveness and easy practicability.Reinforcement elements in a seismic condition such as rock burst have to dissipate the energy release of the dynamic impact via their deformation and ultimate load capacity,knowing that the former is more important.In other words,achieving early stiff behaviour along with large deformation capacity in rockbolts are the goals for new development in rock reinforcement.Yielding rockbolts are expensive while some of them have large deformation capability with low ultimate load capacity.In this paper,modifications were made on encapsulation of rebar rockbolts to utilise it effectively as a yielding reinforcement in seismic conditions.Applying a sufficient decoupled length in the shank of rebar rockbolts which industry has regularly been using to control the bulking of the stress fractured ground,improves the deformation capacity of the bolt.Additionally,leaving a collar bonding underneath of the bearing pad and plate removes the weaknesses of the head anchorage of rockbolt.Therefore the dynamic performance of the bolt is improved by these easily applicable modifications.The behaviour and performance of encapsulated rockbolts have been discussed first,then the effects of modifications are illustrated.The proposed modification of the rebars is not only cost effective but also easy to apply in the field and improves the performance of reinforcements in seismic prone zones.展开更多
The correct method used in forest soil respiration measurement by Li-6400 is a premise of data quality control. According to the study in a larch plantation, collars should be inserted at 12 hours in advance to effici...The correct method used in forest soil respiration measurement by Li-6400 is a premise of data quality control. According to the study in a larch plantation, collars should be inserted at 12 hours in advance to efficiently reduce the influence of CO2 spring-out.Moreover, collar insertion depth substantially affected soil respiration measurement, i.e. when collar was shallowly inserted into soil,transversal gas diffusion and the CO2 re-spring-out caused by unstable collars in the measurement could lead to overestimating soil respiration rate; however, when collar was deeply inserted into soil, root respiration decline caused by root-cut and the most active respiratory of the surface soil separated by the inserted collars could lead to underestimating soil respiration rate. Furthermore, an error less than 5% could be guaranteed in typical sunny day if the target [CO2] was set to the mean value of ambient [CO2] in most time of the day, but it should be carefully set in early morning and late afternoon according to changing ambient [CO2]. This protocol of measurement is useful in real measurement.展开更多
Fabrics of different thickness were selected and made into notch lapels in the experiment. The variation between the outside and inside lapel patterns after the lapel being folded was observed and measured. Besides,ma...Fabrics of different thickness were selected and made into notch lapels in the experiment. The variation between the outside and inside lapel patterns after the lapel being folded was observed and measured. Besides,many factors leading to the variation were analyzed. Then the relation between fold angle and fabric thickness,and the variation of fabric thickness were obtained. The experimental results prove that the biggest horizontal variation between the outside lapel and inside lapel is at the breast line,and when the measuring point is above (or below) the breast line level,the farther it is away from the level,the smaller the variation becomes. In addition,conclusions can be drawn that the thicker the fabric is,the bigger the curve variation will be,and there is a certain mathematic relation between them.展开更多
Local scour around bridge abutments is a widespread problem that can result in structural failure. Collars can be used as a countermeasure to reduce the scour depth. In this study, the temporal scour development aroun...Local scour around bridge abutments is a widespread problem that can result in structural failure. Collars can be used as a countermeasure to reduce the scour depth. In this study, the temporal scour development around a wing-wall abutment was investigated with and without collars. The tests were carried out under clear-water conditions for different abutment lengths, with collars of different sizes placed at the bed level. When no collar was used in the experiments, 70% of the maximum scour depth occurred in less than 2 h. However, when a collar with a width greater than the length of the abutment was used, no scour was observed for up to 200 min from the beginning of the experiments. The results show that an increase in the collar width not only led to a lag time for the onset of scouring but also reduced the maximum scour depth. Moreover, an increased collar width led to a better performance in mitigating scouring around smaller abutments. Generally, the scour depth decreased by 9%-37% with different collar widths.展开更多
The centrifugal casting of compound HSS/nodular cast iron roll collar was studied,and the factors affecting transition zone quality were analyzed.The pouring temperature and interval in pouring are the main factors af...The centrifugal casting of compound HSS/nodular cast iron roll collar was studied,and the factors affecting transition zone quality were analyzed.The pouring temperature and interval in pouring are the main factors affecting transition zone quality.By controlling process parameter and flux adding during casting,high quality roll collar was obtained.The cause,why in the casting of HSS part,segregation appears easily,was analyzed and the countermeasure eliminating segregation was put forward,the measure eliminating heat treatment crackling was also put forward.展开更多
The relation between lining collar and face collar in the collar pattern designed by experiments and theoretical calculation is elucidated. In spite of the same constructions, the collar's shape and the fabric'...The relation between lining collar and face collar in the collar pattern designed by experiments and theoretical calculation is elucidated. In spite of the same constructions, the collar's shape and the fabric's thickness influence on the pattern of lining collar and the face collar, especially on the back center of the Iining and the two collar angles. The thicker the fabric, the more, with a proportional relation, the total variation. It is supposed that this work has made some contribution to the collar pattern design.展开更多
The relations between the lining collar and the face collar in pattern design of standing collar by experiments and theoretical calculation is elucidated. The collar's shape and the fabric thickness, although with...The relations between the lining collar and the face collar in pattern design of standing collar by experiments and theoretical calculation is elucidated. The collar's shape and the fabric thickness, although with the same construction, influence the lining collar and the face collar, especially the back center of the lining and the two collar angles. With a proportional relation, the thicker the fabric is, the more the total variation is. It is supposed to have some practical value to the collar pattern design, as well as to the fashion CAD.展开更多
As the main load-bearing component of fish cages, the floating collar supports the whole cage and undergoes large deformations. In this paper, a mathematical method is developed to study the motions and elastic deform...As the main load-bearing component of fish cages, the floating collar supports the whole cage and undergoes large deformations. In this paper, a mathematical method is developed to study the motions and elastic deformations of elastic floating collars in random waves. The irregular wave is simulated by the random phase method and the statistical approach and Fourier transfer are applied to analyze the elastic response in both time and frequency domains. The governing equations of motions are established by Newton＇s second law, and the governing equations of deformations are obtained based on curved beam theory and modal superposition method. In order to validate the numerical model of the floating collar attacked by random waves, a series of physical model tests are conducted. Good relationship between numerical simulation and experimental observations is obtained. The numerical results indicate that the transfer function of out-of-plane and in-plane deformations increase with the increasing of wave frequency. In the frequency range between 0.6 Hz and 1.1 Hz, a linear relationship exists between the wave elevations and the deformations. The average phase difference between the wave elevation and out-of-plane deformation is 60° with waves leading and the phase between the wave elevation and in-plane deformation is 10° with waves lagging. In addition, the effect of fish net on the elastic response is analyzed. The results suggest that the deformation of the floating collar with fish net is a little larger than that without net.展开更多
We determined a suitable amount of fertilizer for konara oak（Quercus serrata） and Japanese zelkova（Zelkova serrata） planted in a harvested pitch pine（Pinus rigida） plantation. Two-year-old bare-root seedlings of...We determined a suitable amount of fertilizer for konara oak（Quercus serrata） and Japanese zelkova（Zelkova serrata） planted in a harvested pitch pine（Pinus rigida） plantation. Two-year-old bare-root seedlings of konara oak and one-year-old containerized seedlings of Japanese zelkova were planted in April 2011. Three plots were established for each tree species to evaluate each of three fertilization applications. Solid compound fertilizer（N：P：K = 3：4：1） was applied yearly in three amounts（control： no fertilization, F1： 180 kg ha-1, and F2：360 kg ha-1）, every May from 2011 to 2013. We measured the root collar diameter and height, and analyzed the compartmental N and P concentrations. Compartmental N concentrations of konara oak and Japanese zelkova were not consistent based on amount of fertilization. However,the compartmental P concentrations of konara oak and Japanese zelkova were significantly different in the order of F2, F1, and control. Although the differences in growth of konara oak appeared after 3 years of fertilization,Japanese zelkova showed differences after only 2 years of fertilization owing to differences in seedling type. Growth of konara oak was affected by fertilization at F1 and F2 in2013. However, growth of Japanese zelkova was affected only at F2. Nutrient demand of Japanese zelkova appeard to be higher than that of konara oak, at least during the early growing period. Results from this study could be practically used in harvested pitch pine plantations to determine appropriate fertilization regimes.展开更多
深水油田水深达千米以上,为保证水下管道生产系统安全运行,在应急时需要ROV可以紧急关闭水下生产系统,所以在海管终端安装集成多种功能的PLET结构,PLET全称为Pipeline End Termination,此结构可附带关断阀,电仪液压等控制系统,由于集成...深水油田水深达千米以上,为保证水下管道生产系统安全运行,在应急时需要ROV可以紧急关闭水下生产系统,所以在海管终端安装集成多种功能的PLET结构,PLET全称为Pipeline End Termination,此结构可附带关断阀,电仪液压等控制系统,由于集成多种水下控制功能,导致重量大和尺寸大,根据PLET结构的不同也有多种安装方法。文章主要针对多种结构形式PLET的多种安装方法进行研究。展开更多
文摘Background:In bird species where offspring growth and survival rely on parents’food provisioning,parents can maximise their fitness by increasing the quantity and/or the quality of preys delivered to their offspring.Many studies have focused on inter-individual variation in feeding rate,yet this measure may not accurately reflect the total amount of food(i.e.energy)provided by parents if there is large variation in the quantity and quality of preys at each feeding.Here,we explored the relative role of individual(sex,age,body condition),breeding(hatching date,brood size)and environmental(temperature)factors on feeding rate,prey number,size and quality,and their contribution to total prey biomass delivered to the nestlings of 164 Collared Flycatcher(Ficedula albicollis)parents in 98 nests.Results:Preys delivered to the nest were mainly larvae(53.6%)and flying insects(45.6%).Feeding rate increased with brood size and age,and was higher in males than females.Mean prey number decreased,but mean prey size increased,as the season progressed and parents feeding their brood with primary larvae brought more preys per visit.Relationships between feeding rate,mean prey number and size remained when taking into account the provision-ing quality:parents brought either a large number of small prey or a small number of larger items,and the force of the trade-offs between feeding rate and mean prey number and size depended on the quality of the provisioning of the parents.Whatever the percentage of larvae among preys in the provisioning,the variance in total prey biomass was foremost explained by feeding rate(65.1%to 76.6%)compared to mean prey number(16.4%to 26%)and prey size(2.7%to 4%).Conclusions:Our study shows that variation in feeding rate,prey number,size,but not quality(i.e.percentage of lar-vae),were influenced by individual factors(sex and age)and breeding decisions(brood size and timing of breeding)and that,whatever the provisioning strategy adopted,feeding rate was the best proxy of the total biomass delivered to the nestlings.
文摘The trade creation and conservation of wild species in Amazon, including collared peccaries （Pecari tajacu）, may be favored by artificial insemination, but the time of semen storage may lead to reduced fertility in sperm of some wild animals. Thus, the aim of this research was to evaluate the influence of semen storage at 17 ℃ over time on seminal features of peccaries in captivity. Eight adult males were sedated and underwent electroejaculation. The ejaculates （n = 65） were evaluated for volume, concentration, pH, sperm motility, vigor, and cell with intact plasma membrane intact （IPM） and sperm morphology. Selected ejaculates （n = 21） were diluted （1：1） in Beltsville Thawing Solution and kept during 48 hours under controlled temperature （17 ℃）. Assessments were made after dilution （TO）, after 24 hours （T24）, and 48 hours after the onset of cooling （T48）. The storage impacted on sperm survival （P 〈 0.05）. Semen characteristics changed throughout the storage period studied and after 48 hours storage. The decline of sperm motility was of 55.2% for 10.9%, vigor was 2.3 for 0.5 and IPM cells were of 59.0% for 15.8%. Primary defects sperm increased of 19.8% for 32.2%, secondary defects of 9.8% for 10.4% and total defects of 29.4% for 42.7%. However, within 24 hours of preservation, chilled semen peccaries presented sperm motility average rate and IMP cells levels indicative to use in assisted reproductive events. These results indicate chilled semen for 24 hours could be used in experimentally artificial insemination of peccaries, technology that still has not been performed before.
文摘Background:Eurasian Collared Dove(Streptopelia decaocto)is a species distributed in the Eurasian continent and North Africa,and inhabiting mainly in Saitama Prefecture in Japan.Eurasian Collared Dove is one of the most prosper-ous invaders in the world,and Japanese Eurasian Collared Dove has also been introduced from overseas.The Japa-nese population has declined to one-hundredth over 30 years and is being protected.In this study,we analyzed its genetic diversity in order to understand the genetic differences between wild populations of Eurasian Collared Dove and those bred in zoos.Methods:A sequence of about 1.9 kb mtDNA was determined for 20 wild Eurasian Collared Doves living in Saitama,Japan and 20 zoo-bred Eurasian Collared Doves,and population genetic analysis was performed.Results:In the COI gene,778 bp had the same sequence in all the 40 individuals examined,and no mutation sites could be confirmed.In the control region,two base substitution sites were confirmed in 1140 bp long sequence.Three haplotypes were detected in 20 individuals in wild,whereas all 20 zoo-bred individuals possessed the same haplotypes possessed in the wild population.Conclusion:Haplotypes of zoo-bred individuals were also retained among the wild individuals,confirming that no genetic problems could occur if the zoo-bred individuals were released to the wild for the Japanese Eurasian Collared Dove propagation program.
基金supported by the Government of Malaysia under the 10th and 11th Malaysia Plan.
文摘Many tree planting programmes have long been initiated to increase forest cover to mitigate the effects of global climate change.Successful planting requires careful planning at the project level,including using suitable species with favourable traits.However,there is a paucity of improvement data for tropical tree species.An experimental common garden of Shorea leprosula was established to study traits related to growth performance which are key factors in planting success.Seedlings of S.leprosula were collected from nine geographical forest reserves.To study the effects of genetic variation,seedlings were planted in a common environment following a randomized complete block design.From performance data collected 2017‒2019,one population showed the highest coefficient for relative height growth,significantly higher than most of the other populations.Interestingly,this population from Beserah also exhibited the lowest coefficient for scale insect infestation.This study provides preliminary results on growth performance and susceptibility to scale insect infestation in S.leprosula and the first common garden experiment site conducted on dipterocarp species.It lays a foundation for future genome-wide studies.
文摘Collar rot caused the death of Hevea rubber in a village located in Jino County of Xishuangbanna in September, 2012. In order to elucidate the causal agent of collar rot and its taxonomic status, the causal fungus was isolated and identified through a series of tests about its pathogenicity, morphology, culture feature and biological characteristics. The results indicated that the fungus was Fusarium venfrico- sum. It could grow at temperatures ranging from 10 to 40 ℃, and the most suitable temperature was 30 ℃. Its mycelium growth was inhibited above 40 ℃ or below 10 ℃. The accumulated water in wet season was the main reason for this disease occurrence.
基金This paper was supported by National Natural Science Foundation of China （No. 30400341） and Heilongjiang Provincial Science Foundation （No. C0320）Acknowledgement I thank Dr. YAN Xiu-feng for his help and guidance.
文摘A study was conducted to detect the effect of water extracts from different parts such as root, bark, branch and leaf, of adult larch, Larix gmelini, trees on growth of Manchurian walnut, Juglans mandshudca, seedlings and the allelopathy between the two tree species. Four concentrations （100 g. kg i, 50 g. kg^-1, 25 g. kg^-1 and 12.5 g. kg^-1） were prepared for each kind of extracts. Result showed that the water extracts with low and moderate concentrations accelerated the growth of collar diameter and increased biomass and root/shoot ratio of walnut seedlings. The water extracts from branches and barks with low and moderate concentrations accelerated the height growth of the seedlings, while those from leaves and roots slightly decreased the height growth of seedlings. The fact that application of water extracts of larch improved the growth of Manchurian walnut attributes possibly to the allelopathy between the two tree species.
基金funding organisations, Curtin International Postgraduate Scholarship (CIPRS)/Department of Mining and Metallurgy Scholarship, and the Mining Education Australia (MEA), Collaborative Research Grant Scheme [grant number RS-59041]
文摘Rockbolt is widely employed all over the world as an effective ground reinforcement element in order to secure the underground workplaces.Ordinary encapsulated rebar or rebar rockbolt is most popular and commonly used as reinforcement in a ground support system because of its accessibility,cost effectiveness and easy practicability.Reinforcement elements in a seismic condition such as rock burst have to dissipate the energy release of the dynamic impact via their deformation and ultimate load capacity,knowing that the former is more important.In other words,achieving early stiff behaviour along with large deformation capacity in rockbolts are the goals for new development in rock reinforcement.Yielding rockbolts are expensive while some of them have large deformation capability with low ultimate load capacity.In this paper,modifications were made on encapsulation of rebar rockbolts to utilise it effectively as a yielding reinforcement in seismic conditions.Applying a sufficient decoupled length in the shank of rebar rockbolts which industry has regularly been using to control the bulking of the stress fractured ground,improves the deformation capacity of the bolt.Additionally,leaving a collar bonding underneath of the bearing pad and plate removes the weaknesses of the head anchorage of rockbolt.Therefore the dynamic performance of the bolt is improved by these easily applicable modifications.The behaviour and performance of encapsulated rockbolts have been discussed first,then the effects of modifications are illustrated.The proposed modification of the rebars is not only cost effective but also easy to apply in the field and improves the performance of reinforcements in seismic prone zones.
基金National Natural Science Foundation of China (30300271),Program of Key Basic Research from Ministry of Science and Technology (2004CCA02700) and Sina-Japan cooperation project on larch forest study.
文摘The correct method used in forest soil respiration measurement by Li-6400 is a premise of data quality control. According to the study in a larch plantation, collars should be inserted at 12 hours in advance to efficiently reduce the influence of CO2 spring-out.Moreover, collar insertion depth substantially affected soil respiration measurement, i.e. when collar was shallowly inserted into soil,transversal gas diffusion and the CO2 re-spring-out caused by unstable collars in the measurement could lead to overestimating soil respiration rate; however, when collar was deeply inserted into soil, root respiration decline caused by root-cut and the most active respiratory of the surface soil separated by the inserted collars could lead to underestimating soil respiration rate. Furthermore, an error less than 5% could be guaranteed in typical sunny day if the target [CO2] was set to the mean value of ambient [CO2] in most time of the day, but it should be carefully set in early morning and late afternoon according to changing ambient [CO2]. This protocol of measurement is useful in real measurement.
文摘Fabrics of different thickness were selected and made into notch lapels in the experiment. The variation between the outside and inside lapel patterns after the lapel being folded was observed and measured. Besides,many factors leading to the variation were analyzed. Then the relation between fold angle and fabric thickness,and the variation of fabric thickness were obtained. The experimental results prove that the biggest horizontal variation between the outside lapel and inside lapel is at the breast line,and when the measuring point is above (or below) the breast line level,the farther it is away from the level,the smaller the variation becomes. In addition,conclusions can be drawn that the thicker the fabric is,the bigger the curve variation will be,and there is a certain mathematic relation between them.
文摘Local scour around bridge abutments is a widespread problem that can result in structural failure. Collars can be used as a countermeasure to reduce the scour depth. In this study, the temporal scour development around a wing-wall abutment was investigated with and without collars. The tests were carried out under clear-water conditions for different abutment lengths, with collars of different sizes placed at the bed level. When no collar was used in the experiments, 70% of the maximum scour depth occurred in less than 2 h. However, when a collar with a width greater than the length of the abutment was used, no scour was observed for up to 200 min from the beginning of the experiments. The results show that an increase in the collar width not only led to a lag time for the onset of scouring but also reduced the maximum scour depth. Moreover, an increased collar width led to a better performance in mitigating scouring around smaller abutments. Generally, the scour depth decreased by 9%-37% with different collar widths.
文摘The centrifugal casting of compound HSS/nodular cast iron roll collar was studied,and the factors affecting transition zone quality were analyzed.The pouring temperature and interval in pouring are the main factors affecting transition zone quality.By controlling process parameter and flux adding during casting,high quality roll collar was obtained.The cause,why in the casting of HSS part,segregation appears easily,was analyzed and the countermeasure eliminating segregation was put forward,the measure eliminating heat treatment crackling was also put forward.
文摘The relation between lining collar and face collar in the collar pattern designed by experiments and theoretical calculation is elucidated. In spite of the same constructions, the collar's shape and the fabric's thickness influence on the pattern of lining collar and the face collar, especially on the back center of the Iining and the two collar angles. The thicker the fabric, the more, with a proportional relation, the total variation. It is supposed that this work has made some contribution to the collar pattern design.
文摘The relations between the lining collar and the face collar in pattern design of standing collar by experiments and theoretical calculation is elucidated. The collar's shape and the fabric thickness, although with the same construction, influence the lining collar and the face collar, especially the back center of the lining and the two collar angles. With a proportional relation, the thicker the fabric is, the more the total variation is. It is supposed to have some practical value to the collar pattern design, as well as to the fashion CAD.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.51239002 and 51221961)Cultivation Plan for Young Agriculture Science and Technology Innovation Talents of Liaoning Province(Grant No.2014008)
文摘As the main load-bearing component of fish cages, the floating collar supports the whole cage and undergoes large deformations. In this paper, a mathematical method is developed to study the motions and elastic deformations of elastic floating collars in random waves. The irregular wave is simulated by the random phase method and the statistical approach and Fourier transfer are applied to analyze the elastic response in both time and frequency domains. The governing equations of motions are established by Newton＇s second law, and the governing equations of deformations are obtained based on curved beam theory and modal superposition method. In order to validate the numerical model of the floating collar attacked by random waves, a series of physical model tests are conducted. Good relationship between numerical simulation and experimental observations is obtained. The numerical results indicate that the transfer function of out-of-plane and in-plane deformations increase with the increasing of wave frequency. In the frequency range between 0.6 Hz and 1.1 Hz, a linear relationship exists between the wave elevations and the deformations. The average phase difference between the wave elevation and out-of-plane deformation is 60° with waves leading and the phase between the wave elevation and in-plane deformation is 10° with waves lagging. In addition, the effect of fish net on the elastic response is analyzed. The results suggest that the deformation of the floating collar with fish net is a little larger than that without net.
基金supported by the Research Fellowship of the Korea Forest Research Institute in 2013
文摘We determined a suitable amount of fertilizer for konara oak（Quercus serrata） and Japanese zelkova（Zelkova serrata） planted in a harvested pitch pine（Pinus rigida） plantation. Two-year-old bare-root seedlings of konara oak and one-year-old containerized seedlings of Japanese zelkova were planted in April 2011. Three plots were established for each tree species to evaluate each of three fertilization applications. Solid compound fertilizer（N：P：K = 3：4：1） was applied yearly in three amounts（control： no fertilization, F1： 180 kg ha-1, and F2：360 kg ha-1）, every May from 2011 to 2013. We measured the root collar diameter and height, and analyzed the compartmental N and P concentrations. Compartmental N concentrations of konara oak and Japanese zelkova were not consistent based on amount of fertilization. However,the compartmental P concentrations of konara oak and Japanese zelkova were significantly different in the order of F2, F1, and control. Although the differences in growth of konara oak appeared after 3 years of fertilization,Japanese zelkova showed differences after only 2 years of fertilization owing to differences in seedling type. Growth of konara oak was affected by fertilization at F1 and F2 in2013. However, growth of Japanese zelkova was affected only at F2. Nutrient demand of Japanese zelkova appeard to be higher than that of konara oak, at least during the early growing period. Results from this study could be practically used in harvested pitch pine plantations to determine appropriate fertilization regimes.
文摘深水油田水深达千米以上,为保证水下管道生产系统安全运行,在应急时需要ROV可以紧急关闭水下生产系统,所以在海管终端安装集成多种功能的PLET结构,PLET全称为Pipeline End Termination,此结构可附带关断阀,电仪液压等控制系统,由于集成多种水下控制功能,导致重量大和尺寸大,根据PLET结构的不同也有多种安装方法。文章主要针对多种结构形式PLET的多种安装方法进行研究。
