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1.
自走式采茶机液压系统的设计和试验研究 总被引:1,自引:0,他引:1
为了设计简单、合理、可靠的自走式采茶机液压系统,首先进行了其液压系统原理与选型设计,并利用Sim Hydraulic对液压系统进行了功能数值仿真,最后进行样机试验。行驶液压子系统采用双泵双回路闭式容积调速方案,单个回路由双向变量泵与定量马达实现容积调速,系统设计压力为17.6 MPa。采摘子系统为一般开式回路,设计系统压力为10 MPa。系统压力的仿真结果与设计值分别相差2.78%和0.91%,试验结果与设计值分别相差为4.82%和14.3%,仿真、试验结果与设计目标基本相符,表明设计的液压系统能够很好地满足自走式采茶机的作业要求。 相似文献
2.
分析了离心泵和单螺杆泵在乳胶生产中的运行缺点,并对这2种泵设备进行了改造,在实际生产中起到了方便、实用和高效的效果。 相似文献
3.
Changes in the lignin and hemicellulose concentrations of ten varieties of temperate grasses with increasing maturity 总被引:2,自引:0,他引:2
I. M. MORRISON 《Grass and Forage Science》1980,35(4):287-293
The lignin and total hemicellulose concentrations of ten varieties of temperate grasses (five species) were determined with increasing maturity. A strong correlation existed between the lignin and hemicellulose concentrations. Lignin and hemicellulose concentrations tended to be higher in cocksfoot and timothy than in perennial ryegrass and diploid varieties also had higher lignin and hemicellulose concentrations than their tetraploid counterparts. The hemicellulose fractions were further separated into their linear and branched components whose compositions were determined. The varieties with higher lignin concentrations showed a higher linear:branched ratio and the 'linear' components also had higher xylose: arabinose ratios. These findings were consistent for both leaf and stem tissue although the effects from stem tissue were more marked. 相似文献
4.
《Journal of Crop Improvement》2013,27(2):287-298
Summary It is well known that C4 crops have a lower water requirement than C3 crops. Reasons for the difference are not well understood. Therefore, hydraulic resistance of sorghum [Sorghum bicolor (L.) Moench] (C4) and sunflower (Helianthus annuus L.) (C3) was determined to see if it might be one explanation for the lower water use of crops with the C4 photosynthetic pathway. Plants were grown under greenhouse conditions in pots with soil, which was well watered (soil matric potential of ~0 MPa) or allowed to dry (soil matric potential of ?0.038 MPa and ?0.065 MPa for sorghum and sunflower, respectively). Hydraulic resistance was calculated in two ways: (1) using the classic Ohm's law analogue, which assumes that the relation between flux (transpiration) and difference in water potentials of the soil and plant is linear and (2) using an equation that considers diurnal changes in leaf water content along with transpiration and difference in water potentials. Because change in leaf-water content during a day was small, hydraulic resistances calculated by the two methods resulted in similar values. Sorghum had a linear relationship between flux and difference in potentials (constant hydraulic resistance), but sunflower had a nonlinear one (variable hydraulic resistance). The hydraulic resistance of watered sunflower increased only slightly during a day and averaged about 40 MPa m2 s mol?1, which was 3.5 times less than that of watered or water-stressed sorghum (-140 MPa m2 s mol?1). The hydraulic resistance of water-stressed sunflower increased steeply during a day and by the end of the day it had a hydraulic resistance that approached that of sorghum. 相似文献
5.
Salman Naeem Vijay Baheti Jiri Militky Jakub Wiener Promoda Behera Azeem Ashraf 《Fibers and Polymers》2016,17(8):1245-1255
In this study, impregnation of iron chloride was carried out on needle punched web of waste acrylic fibers, which was subsequently carbonized under layer of charcoal by physical activation in high temperature furnace to produce iron impregnated activated carbon (FeAC). For comparison purpose, one more sample of activated carbon (AC) was prepared without impregnation of iron chloride. Both the webs were carbonized at 1200 °C with no holding time, and characterization of BET surface area, SEM morphology, EDX elemental analysis, XRD crystalline structure was performed. The FeAC web was used as adsorbent for the removal of methylene blue from aqueous solution. The dye removal percentage was investigated at different experimental parameters like different dye concentrations, adsorbent dosage, stirring speed and different pH. The obtained results were analyzed using linear and non-linear forms of Langmuir and Freundlich isotherms and adsorption kinetics (i.e. pseudo first order and pseudo second order model). 相似文献
6.
Bernt O. Myrvold 《Industrial Crops and Products》2008,27(2):214-219
Lignosulphonates are formed by the cleavages of the α-O-4 linkages of the “infinite” lignin network in wood, and a sulphonation of the α- and/or γ-positions of the side chains of the C9 units. The resulting lignosulphonate molecule forms a randomly branched polyelectrolyte. The molecule coils in solution to make a more ball-shaped molecule with the sulphonate groups enriched on the surface. The scaling laws for this model of the lignosulphonate polymer as well as for other models of the lignosulphonate have been derived. The scaling laws for the randomly branched polyelectrolyte and microgel are the same for most properties except the polyelectrolyte expansion. The scaling laws are compared with literature experimental values for radii and polyelectrolyte expansion. The randomly branched polyelectrolyte model successfully accounts for the behaviour in solution. The dependence of the polyelectrolyte expansion on the molecular weight demonstrates that the lignosulphonate is not a microgel structure. 相似文献
7.
Soon Yong Chun Han Jo Bae Seon Mi Kim Moon W. Suh P. Grady Won Seok Lyoo Won Sik Yoon Sung Soo Han 《Fibers and Polymers》2006,7(1):62-65
Making a good model is one of the most important aspects in the field of a control system. If one makes a good model, one is now ready to make a good controller for the system. The focus of this thesis lies on system modeling, the draft system in specific. In modeling for a draft system, one of the most common methods is the “least-square method”; however, this method can only be applied to linear systems. For this reason, the draft system, which is non-linear and a time-varying system, needs a new method. This thesis proposes a new method (the MLS method) and demonstrates a possible way of modeling even though a system has input noise and system noise. This thesis proved the adaptability and convergence of the MLS method. 相似文献
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Changes on the CIELab values of the dyed materials after the different chemical finishing treatments using artificial neural
network (ANN) and linear regression (LR) models have been predicted. The whole structural properties of fabrics and some process
data which were from fiber to the finishing parameters were accepted as inputs in these models. The networks having different
structures were established, and it was also focus on the parameters which could affect the performance of the established
networks. It was determined that we could successfully predict the color differences values occurring on the material after
the finishing applications. In addition, we realized that some ANN parameters affected the prediction performance while establishing
the models. After training ANN models, the prediction of the color difference values was also tried by linear regression models.
Then, extra ANN models were established for all outputs using the parameters as inputs in the LR equations, and the prediction
performances of both established models were compared. According to the results, the neural network model gives a more accurate
prediction performance than the LR models. 相似文献
10.
Problems caused by water shortage in a paddy-field district with a pipeline network system are different from those in a district with an open channel system. Abnormally low rainfall in Japan caused a very serious water shortage in 1994. A survey was carried out in the Hokuriku region, about 300 km in the north of Tokyo, and a typical paddy cultivation area, to determine problems in irrigation practices caused by water shortage and to find countermeasures for the problems. The following results were obtained. A tank model was proposed to estimate water requirements at the field level. The results showed that the amount of rainfall during the irrigation period in 1994 was only 27.1% of an average year and the rate of water sufficiency at the field level was 70.6%. Then, a simulation method was proposed to estimate hydraulic phenomena in a pipeline network system. The result showed that the pipeline network system distributed water to each hydrant unequally during water shortage. Based on simulations, the methods to equalize water supply to each hydrant and to set up reuse system of water were proposed. 相似文献
11.
《Plant Production Science》2013,16(2):139-149
AbsractThis technical report describes a gradient system for characterizing the vertical gradients of CO2, H2O, and air temperature within and above the canopy of plants. The system is low in cost and easy to use. The instruments were fitted and placed in one box with a total weight of about 10 kg. The box can be carried and moved from one site to another. The features of this apparatus are high frequency sampling cycle as short as 1 min per cycle for all six measurement levels and fast response gas analyzer for measurement as short as 10s per level. Two exhaust pumps, one sampling pump, six 3-way solenoid valves, and flow meter were used to insure simultaneous flow rate of air in all tubes from all measurement levels. This system transfers data from the data-logger directly to the add-in Spreadsheet of Microsoft Excel by using an Ethernet cable to automatically convert digital data to scientific units in less time. This system also allows the use of multiple micro-environmental sensors that can be sampled at the same time. It is useful not only for agricultural ecosystems but is also adequately sensitive and rapidly responds to the gas analyzer with a modifiable flow rate meter for use in forest ecosystems. This system also has potential for use in the measurement of CO2, H2O, associated environmental elements, and CO2 storage flux within the canopy of plant, and other processes including a CO2 sink and source. 相似文献
12.
Fernando Dures Nikoletta Szemerdi Decha Kumla Madalena Pinto Anake Kijjoa Gabriella Spengler Emília Sousa 《Marine drugs》2021,19(9)
Marine-derived fungi constitute an interesting source of bioactive compounds, several of which exhibit antibacterial activity. These acquire special importance, considering that antimicrobial resistance is becoming more widespread. The overexpression of efflux pumps, capable of expelling antimicrobials out of bacterial cells, is one of the most worrisome mechanisms. There has been an ongoing effort to find not only new antimicrobials, but also compounds that can block resistance mechanisms which can be used in combination with approved antimicrobial drugs. In this work, a library of nineteen marine natural products, isolated from marine-derived fungi of the genera Neosartorya and Aspergillus, was evaluated for their potential as bacterial efflux pump inhibitors as well as the antimicrobial-related mechanisms, such as inhibition of biofilm formation and quorum-sensing. Docking studies were performed to predict their efflux pump action. These compounds were also tested for their cytotoxicity in mouse fibroblast cell line NIH/3T3. The results obtained suggest that the marine-derived fungal metabolites are a promising source of compounds with potential to revert antimicrobial resistance and serve as an inspiration for the synthesis of new antimicrobial drugs. 相似文献
13.
Starch is composed of two glucose polymers: amylose, formed by long linear chains, and amylopectin, which is larger and highly branched. The ratio between the two polymers (usually 22–35% amylose, 68–75% amylopectin) affects the starch properties, thereby determining different aspects of wheat quality. Waxy protein, which is the sole enzyme responsible for amylose synthesis, showed polymorphism in a collection of one hundred and three Mexican landraces, including null alleles at Wx-A1 and Wx-B1 loci, respectively. Molecular characterization of these alleles showed that the null Wx-A1 allele presented in only one accession was novel (Wx-A1o) and involved a deletion spanning the three and a half last exons of the gene. Some of the accessions lacking the Wx-B1 protein contained the common allele Wx-B1b (12.6%) (deletion of approximately 67 kb), while four others (3.8%) possessed the novel Wx-B1l, characterized by the deletion of one cytosine in the second exon of the gene and leading to a change in the ORF. This novel allele is particularly interesting because the absence of the Wx-B1 protein in this case was not associated with the lack of the other genes included in the approximately 67 kb region lost with the common null allele Wx-B1b. 相似文献
14.
为了解水分胁迫下施肥对冬小麦根系提水及养分利用的影响以及水肥在小麦生长过程中的协同效应,采用两室分根土培方法,通过对上下两个土层(上层:0~20 cm;下层:20~60 cm)含水量进行控制和观测,分析了不同水分处理间小麦根系提水量、养分积累和表现利用率的差异。结果表明,在土壤上干下湿(DW)条件下冬小麦系提水作用明显,施肥处理对冬小麦全生育期根系提水量有明显影响,表现为氮磷配施、单施磷>对照(不施肥)>单施氮。在氮磷配施条件下,小麦植株及各器官氮磷养分累积量高于其他施肥处理(单施磷、对照和单施氮),各施肥条件下植株氮磷素累积量均表现为WW>DW>DD。氮磷肥表观利用率明显高于单施氮或单施磷处理,且表现出DW和WW(上下土层均湿润)处理的氮磷肥表观利用率均高于DD水分处理(上下土层均干燥)。由此可见,氮磷配施可明显提高水分胁迫(DW)下小麦根系从土壤深层的提水作用,同时促进植株对氮磷养分的积累和利用,实现水肥相互协同。 相似文献
15.
Han Jo Bae Youn-Sung Kim Soon-Yong Chun Un-Ho Ji Mu Han Kim Sung Soo Han 《Fibers and Polymers》2008,9(3):323-327
High regularity is important in manufacturing spun yarn. Among controllers used in regularity control, existing PID controller
is suitable for linear time-invariant systems but not for the control of sliver draft systems with non-linear characteristic.
Thus, the present study designed a knowledge-based fuzzy controller in consideration of disturbance and non-linear characteristic
of sliver draft systems. RLS (Recursive Least Squares) was used as an estimation algorithm to formulate a model used in computer
simulation for implementing the controller, and real time estimation was made using real data from draft systems to get a
model close to actual systems. This research used a estimation model in designing a knowledge-based controller that minimizes
the variation of control response to the sliver linear density of the system, and the result of linear density control was
used to prove the superiority of the controller in control performance through CV%. 相似文献
16.
The purpose of this study was to examine the effects of the structural properties of plain knit fabrics on the subjective
perception of textures, sensibilities, and preference among consumers. This study, then, aimed to provide useful information
with respect to planning and designing knitted fabrics by predicting the subjective characteristics analyzed according to
their structural properties. For this purpose, we employed statistical analysis tools, such as factor and regression analysis
and an adaptive-network-based fuzzy inference system(ANFIS), thereby combining the merits of fuzzy and neural networks and
presupposing a non-linear relationship. Through factor analysis, we also categorized the subjective textures into ‘roughness’,
‘softness’, ‘bulkiness’ and ‘stretch-ability’ with R2=70.32 %: and categorized the sensibilities into ‘Stable/Neat’, ‘Natural/Comfortable’
and ‘Feminine/Elegant’ with R2=68.12 %. We analyzed subjective textures, sensibilities, and preference with ANFIS, assuming
non-linear relationships; consequently, we were able to generate three or four fuzzy rules using wool/rayon fiber content
and loop length as input data. The textures of roughness and softness exhibited a linear relationship, but other subjective
characteristics demonstrated a non-linear input-output relationship. Compared with linear regression analysis, the ANFIS exhibited
had higher predictive power with respect to predicting subjective characteristics. 相似文献
17.
To predict soil moisture condition in arbitral agricultural lands by taking spatial distribution of soil type in a watershed into account, we investigated the possible proper methods of determining the soil hydrological parameters using available soil physical properties database of Japanese soils, “SolphyJ”, and the digital soil map. In this study, simulation of soil moisture was conducted at three neighboring locations, including monitoring sites each in Toyama and Fukui cities. The simulated results of soil moisture appeared to be improved when hydraulic parameters were obtained by fitting water retention data of SolphyJ compared to the parameters estimated by neural network with soil texture and dry bulk density data. It is probably because peculiar soil structure in each field could affect the hydraulic properties more than the soil texture. Simulation results also indicated that soil moistures are much different even if they are located in neighbors (<5 km). We concluded that combination of these two databases is useful for estimating soil hydraulic parameters and to predict soil moisture condition in arbitrary agricultural lands. 相似文献
18.
研究基于3G混合网络和WIFI无线技术实现琯溪蜜柚果园移动视频监控系统。系统充分利用3种不同3G网络资源优势,在3G移动终端上实现了"任何时间、任何地点、任何终端"无缝式的无线监控系统,有效地弥补了传统网络视频监控的弱势,可为果园管理提供更高效、系统的解决方案,提高了农业生产效率和管理水平。 相似文献
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