A Preliminary Study on Models of Root Water Uptake Based on Root Weight

Water uptake by crop roots is influenced by many factors. In this study, on the basis of previous studies, root water uptake models were established with the root weight as a dependent variable from the perspective of root biomass changes according to the theory of soil water dynamics. The established models were verified and evaluated using two indicators： root-mean-square error （RMSE） and mean absolute percentage error （MAPE）. The results indicated that the annual variation range of root-mean-square error （RMSE） was 0.477-1.231, with an aver- age of 0.810; the annual variation range of mean absolute percentage error （MAPE） was 1.082%-4.052%, with an average of 2.520%, suggesting that the simulation accuracy basically met the requirements. The established numerical models of root water uptake and the compiled program exhibit high simulation accuracy, which can perfectly simulate soil water dynamics during the growth period of crops under nat- ural conditions.

Acupuncture at the “Huatuojiaji” point affects nerve root regional interleukin-1 level in a rat model of lumbar nerve root compression

BACKGROUND：It has been shown that interleukin-1 （IL-1） may cause inflammatory reactions, which stimulate the nerve root of patients with lumbar intervertebral disc protrusion and leads to pain. Whether the clinical curative effects of acupuncture in the treatment of lumbar and leg pain are linked to an inhibition of local IL-1 secretion is unknown. OBJECTIVE： To assess the influence of acupuncture on IL-1, this study was designed to verify the effects of acupuncture at the ＂Huatuojiaji （Extra）＂ point on the nerve root in a rat model of lumbar nerve root compression, compared with administration of meloxicam, a non-steroidal anti-inflammatory drug. DESIGN, TIME AND SETTING： Randomized, controlled, molecular biology experiment, performed at the Experimental Center, Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University between September 2005 and April 2006. MATERIALS： Forty healthy adult Sprague Dawley rats of either gender were included in this study. The rats were randomly and evenly divided into the following four groups： normal control, model, acupuncture and meloxicam groups. Lumbar nerve root compression was induced in rats in the model, acupuncture, and meloxicam groups by inserting a specially made silicon rubber slice at the juncture of the L5 nerve root and the dural sac. The acupuncture needle （pattern number N3030, 30#, 1.5 inch） was purchased from Suzhou Medical Appliance Factory, China. IL-1 enzyme linked immunosorbent assay （ELISA） kit was purchased from Santa Cruz Biotechnology, Inc., USA. METHODS： The acupuncture group was acupunctured at the ＂Huatuojiaji＂ point, which is lateral to the compressed L5-6 nerve root, with an acupuncture depth of 0.5 cm. There were two treatment courses, each of involved seven 20-minute acupuncture sessions, one session a day. The meloxicam group was administered intragastrically 3.75 mg/kg meloxicam （5 mg meloxicam /10 mL physiological saline）. Rats in the normal control group and model group received an intragastric administration of 10 mL/kg physiological saline. All administrations were performed once a day. MAIN OUTCOME MEASURES： At day 14 post-surgery, the IL-1 level in the compressed nerve root was determined by a streptavidin-peroxidase （S-P） immunohistochemical method, and IL-1β mRNA expression in the compressed nerve root was simultaneously detected by real-time reverse transcription-polymerase chain reaction. RESULTS： The expression levels of IL-1 and IL-1β mRNA in the L5 nerve root were significantly higher in the model group than in the control group （P 〈 0.01）. However, the expression levels of IL-1 and IL-1β mRNA were significantly lower in the acupuncture and meloxicam groups than in the model group （P 〈 0.05–0.01）. Expression levels of IL-1 and IL-1β mRNA were significantly higher in the acupuncture group than in the meloxicam group （P 〈 0.01）. CONCLUSION： Acupuncture at the ＂Huatuojiaji＂ point decreases the IL-1 level by inhibiting IL-1β mRNA expression to a greater extent than meloxicam administration.

Effect of warm acupuncture on nitric oxide synthase and calcitonin gene-related peptide in a rat model of lumbar nerve root compression

BACKGROUND： Varying degrees of inflammatory responses occur during lumbar nerve root compression. Studies have shown that nitric oxide synthase （NOS） and calcitonin gene-related peptide （CGRP） are involved in secondary disc inflammation. OBJECTIVE： To observe the effects of warm acupuncture on the ultrastructure of inflammatory mediators in a rat model of lumbar nerve root compression, including NOS and CGRP contents. DESIGN, TIME AND SETTING： Randomized, controlled study, with molecular biological analysis, was performed at the Experimental Center, Sixth People＇s Hospital Affiliated to Shanghai Jiao Tong University, between September 2006 and April 2007. MATERIALS： Acupuncture needles and refined Moxa grains were purchased from Shanghai Taicheng Technology Development Co., Ltd., China; Mobic tablets were purchased from Shanghai Boehringer Ingelheim Pharmaceuticals Co., Ltd., China; enzyme linked immunosorbent assay （ELISA） kits for NOS and CGRP were purchased from ADL Biotechnology, Inc., USA. METHODS： A total of 50, healthy, adult Sprague-Dawley rats, were randomly divided into five groups normal, model, warm acupuncture, acupuncture, and drug, with 10 rats in each group. Rats in the four groups, excluding the normal group, were used to establish models of lumbar nerve root compression. After 3 days, Jiaji points were set using reinforcing-reducing manipulation in the warm acupuncture group. Moxa grains were burned on each needle, with 2 grains each daily. The acupuncture group was the same as the warm acupuncture group, with the exception of non-moxibustion. Mobic suspension （3.75 mg/kg） was used in the oral drug group, once a day. Treatment of each group lasted for 14 consecutive days. Modeling and medication were not performed in the normal group. MAIN OUTCOME MEASURES： The ultrastructure of damaged nerve roots was observed with transmission electron microscopy; NOS and CGRP contents were measured using ELISA. RESULTS： The changes of the radicular ultramicrostructure were characterized by Wallerian degeneration; nerve fibers were clearly demyelinated; axons collapsed or degenerated; outer Schwann cell cytoplasm was swollen and its nucleus was compacted. Compared with the normal group, NOS and CGRP contents in the nerve root compression zone in the model group were significantly increased （P 〈 0.01）. Nerve root edema was improved in the drug, acupuncture and the warm acupuncture groups over the model group. NOS and CGRP expressions were also decreased with the warm acupuncture group having the lowest concentration （P 〈 0.01）. CONCLUSION： In comparison to the known effects of Mobic drug and acupuncture treatments, the warm acupuncture significantly decreased NOS and CGRP expression which helped improve the ultrastructure of the compressed nerve root.

Model Study of IPMC Beam Electroactive Response Based on Root Deformation

Ionic polymer-metal composite （IPMC） is a type of electroactive polymer （EAP）. In this paper, based on Nemat-Nasser model, an improved model is developed to explain the initial nonlinear response of electric actuation on the fixed end deformation. Three IPMC strip samples with different surface resistance are chosen for analysis. Further, from simulation and experiment results, it is found that the root deformation made the tip movement of the IPMC strip with little surface resistance, but this effect was less and less when the surface resistance reduced. The calculation results of this model for the fixed end show a more accurate simulation for the actual deformation of IPMC strips.

Modeling Methods and Test Verification of Root Insert Contact Interface for Wind Turbine Blade

Two modeling methods of the root insert for wind turbine blade are presented,i.e.,the local mesh optimization method(LMOM)and the global modeling method(GMM).Based on the optimized mesh of the local model for the metal contact interface,LMOM is proposed to analyze the load path and stress distribution characteristics,while GMM is used to calculate and analyze the stress distribution characteristics of the resin layer established between the bushing and composite layers of root insert.To validate the GMM,a tension test is carried out.The result successfully shows that the shear strain expresses a similar strain distribution tendency with the GMM′s results.

Ensemble Based Temporal Weighting and Pareto Ranking (ETP) Model for Effective Root Cause Analysis

Root-cause identification plays a vital role in business decision making by providing effective future directions for the organizations.Aspect extraction and sentiment extraction plays a vital role in identifying the rootcauses.This paper proposes the Ensemble based temporal weighting and pareto ranking(ETP)model for Root-cause identification.Aspect extraction is performed based on rules and is followed by opinion identification using the proposed boosted ensemble model.The obtained aspects are validated and ranked using the proposed aspect weighing scheme.Pareto-rule based aspect selection is performed as the final selection mechanism and the results are presented for business decision making.Experiments were performed with the standard five product benchmark dataset.Performances on all five product reviews indicate the effective performance of the proposed model.Comparisons are performed using three standard state-of-the-art models and effectiveness is measured in terms of F-Measure and Detection rates.The results indicate improved performances exhibited by the proposed model with an increase in F-Measure levels at 1%–15%and detection rates at 4%–24%compared to the state-of-the-art models.

Stimulatory Effects of NMDA on Intracellular Ca^(2+) Nonlinear Kinetic Model in Rat Dorsal Root Ganglion Neurons

The present study revealed the stimulatory effects of NMDA on intracellular ca 2+ concentration in rat dorsal root ganglion (DRG) neurons. Fura 3/AM, an intracellular calcium fluorescent indicator was used to monitor the fluctuation of 〔ca 2+ 〕 i. Here we present the evidence that (1) Confocal microscopy resolved the cells of three different sizes, based on which a cell diameter distribution histogram was drawn. The fluorescence signals originated from the cells of different sizes, small size (diameter<30μm), medium size (diameter between 30 to 50μm),and large size (diameter>50μm); presumably intracellular Ca 2+ concentration was different in the cells of different sizes. (2) The time related variation of fluorescence intensity was observed. In particular, the fluorescence intensity in 0 Ca 2+ bath solution was affected by the application of high ca 2+ solution. (3) In 0 ca 2+ bath solution the intracellular Ca 2+ concentration nonlinear properties of distinct diameter cells was described. (4) A kind of SETAR model was fitted with a medium sized cell.(5)The residuals from the fitted model were tested to see whether they were plausibly Gaussian. These findings indicated that in distinct types of cells intracellular Ca 2+ concentration had different characteristics in different DRG neurons, and contributed to different functions of these neurons. Besides, the established threshold autoregressive model can share intracellular ca 2+ with the main nonlinear kinetic

Anisotropic Models of Human Pulmonary Root with Bicuspid Pulmonary Valve in Patients with Tetralogy of Fallot: Pulmonary Root Function Assessment and Mechanical Stress Analysis

Background Tetralogy of Fallot(TOF)is the most common cyanotic heart defect,accounting for 10%of all congenital defects.Pulmonary valve stenosis(PVS)is one common right ventricular outflow tract obstruction problem in patients with TOF.Congenital bicuspid pulmonary valve(BPV)is a condition of valvular stenosis,which morphologic feature is the presence of only two pulmonary leaflets instead of the normal tri-leaflet.Congenitally BPV are uncommon and the occurrence is often associated with TOF.Methods The three-dimensional geometric reconstruction of pulmonary root(PR)were based on well-accepted mathematical analytic models with physiological parameters obtained from a typical sample of the pulmonary root used in clinical surgery.The PR geometry included valvular leaflets,sinuses,interleaflet triangles and annulus.The dynamic computational models of normal PR with tri-leaflet and PR with BPV in patients with TOF were developed to investigate the effect of geometric structure of BPV on valve stress and strain distributions and the geometric orifice area.Mechanical properties of pulmonary valve leaflet were obtained from biaxial testing of human pulmonary valve left leaflet,and characterized by an anisotropic Mooney-Rivlin model.The complete cardiac cycle was simulated to observe valve leaflet dynamic stress and strain behaviors.Results Our results indicated that stress/strain distribution patterns of normal tri-leaflet pulmonary valve(TPV)and the BPV were different on valve leaflets when the valve was fully open,but they were similar when valves were completely closed.When the valve was fully open,the BPV maximum stress value on the leaflets was 218.1 kPa,which was 128.0%higher than of the normal TPV value(95.6 kPa),and BPV maximum strain value on the leaflets was 70.7%higher than of the normal TPV.The location of the maximum stress from TPV and BPV were also different,which were found at the bottom of the valve near the leaflet attachment for TPV and the vicinity of cusp of the fusion of two leaflets for BPV,respectively.During the valve was fully open,the stress distribution in the interleaflet triangles region of the PR was more asymmetric in the BPV model compared with that in the normal TPV model,and the largest change on the PR with the geometrical variations in the two models was 39.6%in maximum stress.This stress asymmetry indicates that BPV may be one of the causes of post-stenotic pulmonary artery dilatation and aneurysm in patients with TOF.The cusp of the BPV model showed significant eccentricity during peak systolic period,and its geometric orifice area value in the completely opened position of valve was reduced 57.5%from that of the normal TPV model.Conclusions Our initial results demonstrated that valve geometrical variations with BPV may be a potential risk factor linked to occurrence of PVS in patients with TOF.Computational models could be used as an effective tool to identifying possible linkage between pulmonary valve malformation disease development and biomechanical factors,better design of artificial valves and new surgical procedures without testing those on patients.Large-scale clinical studies are needed to validate these preliminary findings.

Influence of species,age and weight on the establishment of a murine model of brachial plexus root avulsion

BACKGROUND： Animal models of brachial plexus root avulsion are required for the study of brachial plexus root injuries. The established ventral approach results in slight injuries, and is similar to mechanisms underlying human brachial plexus root avulsion.OBJECTIVE： To analyze the effects of weight, age, and species on the success rate of brachial plexus root avulsion, and to determine the perfect method for establishing models of brachial plexus root avulsion.DESIGN, TIME AND SETTING： A randomized, block design was performed at the Laboratory of Professor Lihua Zhou, Zhongshan School of Medicine, Sun Yat-sen University, China from June 2008 to June 2009.MATERIALS： Sprague Dawley （SD） rats, golden hamsters, and BALb/C mice were used in the present study.METHODS： All animals were randomly subjected to classical brachial plexus root avulsion and modified brachial plexus root avulsion.MAIN OUTCOME MEASURES： Success rate of brachial plexus root avulsion. RESULTS： The success rate of brachial plexus root avulsion was greater in the modified group than in the classical group （P〈0.01）. Moreover, the difference was significant in 15-day-old SD rats, 5-week-old SD rats, and 3-month-old BALb/C mice （P〈0.01）. The success rate of brachial plexus root avulsion was greater in the same weight, 15-day-old juvenile SD rats, than in the 3-month-old BALb/C mice （classical group, P〈0.01; modified group, P〈0.05）. The success rate of brachial plexus root avulsion was significantly greater in 3-month-old golden hamsters than in 5-week-old SD rats in the classical group （P〈0.05）. The success rate of brachial plexus root avulsion was significantly lower in the 15-day-old SD rats compared with the 5-week-old and 3-month-old SD rats in the classical group （P〈0.01）. However, there was no significant difference in the success rate of brachial plexus root avulsion between various ages of SD rats in the modified group （P〉0.05）.CONCLUSION： Modified surgery to induce brachial plexus root avulsion significantly increases the success rate of model establishment. Species, age, and weight affect the success rate of brachial plexus root avulsion, and species plays an important role in the success rate.

Effect of Tire Repeated Root Modal on Tire Modelling with Experimental Modal

The effect of tire repeated root modal（RRM）on tire modeling with an experimental modal is studied.Firstly,a radial tire with radial and tangential RRMs is tested and analyzed.By multi-point exciting of the radial tire,a multiple reference frequency domain method based on a least squares（LMS PolyMAX）algorithm is used to identify modal parameters.Then,modal stability diagram（MSD）,modal indication function（MIF）and modal assurance criteria（Auto-MAC）matrix are utilized to induce multiple inputs multiple outputs（MIMO）frequency response function（FRF）matrixes.The tests reveal that notable repeated roots exist in both radial and tangential response modes.Their modal frequencies and damping factors are approximately the same,the amplitudes of modal vectors are in the same order of magnitude,and the mode shapes are orthogonal.Based on the works mentioned,the method of trigonometric series modal shapes fitting is adopted,the effects of RRM model on tire modeling with a vertical experimental modal are discussed.The final results show that the effects of considering the RRM shapes are equivalent to the tire mode shapes depended on rotating the tire’s different exciting points during tire modeling,and since considering the RRM,the tire mode shapes can be unified and fixed during tire modeling.

Square-Root Dynamics of a SIR-Model in Fractional Order

In this paper, we consider an SIR-model for which the interaction term is the square root of the susceptible and infected individuals in the form of fractional order differential equations. First the non-negative solution of the model in fractional order is presented. Then the local stability analysis of the model in fractional order is discussed. Finally, the general solutions are presented and a discrete-time finite difference scheme is constructed using the nonstandard finite difference (NSFD) method. A comparative study of the classical Runge-Kutta method and ODE45 is presented in the case of integer order derivatives. The solutions obtained are presented graphically.

Modelling and verification of a new Roots blower profile based on analysis of performance of different leaf contour

The rotor of a Roots blower is the key component relating to its capability, so the profile design of the rotor in a Roots blower is extremely important. We focused on the modelling and verification for a novel Roots blower tooth profile based on the performance analysis. By comparing the area utilization coefficient and the ratio of several traditional rotor profiles, we proposed a new rotor profile. Then, we further accomplished the mathematical modelling of the proposed rotor profile and the computational fluid dynamics(CFD) simulation, and obtained the Roots blower outlet flow monitoring curves. Finally, we verified the characteristics by a physical experiment.

Characterization of Cassava Root Husk Powder: Equilibrium, Kinetic and Modeling Studies as Bioadsorbent for Copper(II) and Lead(II)

This study was aimed to investigate Pb(II) and Cu(II) ions removal ability from aqueous solution by cassava root husks (CRH) as a cheap, sustainable and eco-friendly bioadsorbent. The CRH was characterized by Fourier Transform Infrared (FTIR) spectroscopy which indicated the availability of various functional groups for metal coordination and the result was supported by elemental analysis studies. UV-Visible spectral studies indicated the presence of oxalate () and it could possibly interact with metal ions to give rise to a stable chelated coordination complex which affects metal ions removal efficiency. Bioadsorption process was carried out as a function of metal concentration, contact time, pH of the solution, particle size, and dosage of the adsorbent. Experimental results indicated the optimal adsorption condition of pH 4 for both Pb(II) and Cu(II) ions, dosage of 0.1 g/0.1L and 1 g/0.1L for Pb(II) and Cu(II) ions respectively, adsorption equilibrium time of 2 and 25 minutes for Pb(II) and Cu(II) respectively, and concentration of 0.5 mg/L for both metal ions. Kinetic data best fitted pseudo-second-order model and not the pseudo-first-order model. Equilibrium data best fitted the Freundlich model than the Langmuir model. Specific surface area and pore volume studies indicated that CRH is non-porous and hence rapid adsorption kinetics is expected. Supporting the experimental results, molecular modeling studies performed using Schrödinger software predicted several sites in the structure capable of docking with metal ions.

Effects of Raspberry Root decoction on cytokine level and thymus and spleen index in S180 model mice

Objective: To observe the effects of RRD on serum levels of cytokines interleukin-2 (IL-2), interleukin-10 (IL-10) and thymus and spleen index in S180 mice, and to explore the mechanism of tumor inhibition by RRD. Methods: Fifty Kunming healthy mice, half male and half female, were randomly divided into five groups: normal control group, model control group, cyclophosphamide group (CTX group), red raspberry group (RRD group) and combined administration of red raspberry and cyclophosphamide group (RRD + CTX group), with 10 mice in each group only. The other 40 mice were injected with 0.2 mLS180 tumor suspension at the right axilla to make the model experiment, except 10 mice in the normal control group. The next day, the normal control group and model control group were given intragastric administration of 0.02 mL/g/d saline, CTX group was given intragastric administration of 0.4 mL/20 g/d saline and 20 mg/kg/d CTX, RRD group was given intragastric administration of 0.4 mL/20 g/d RRD, RRD+CTX group was given intragastric administration of 0.4 mL/20 g/d RRD and 20 mg/kg/d CTX for 10 d, once a day. Serum levels of IL-2 and IL-10 were measured by ELISA, and thymus and spleen indexes were measured. Results: Red raspberry rhizome decoction could increase serum IL-2 level (P < 0.05), decrease IL-10 level (P < 0.05), increase thymus index (P < 0.05) and decrease spleen index (P < 0.05) in S180 mice. Conclusion:The anti-tumor effect of the water decoction of red raspberry rhizome may be related to the regulation of immune suppression and the improvement of immune organ function of the tumor-bearing organism.

FracRoot模型在橡胶树根系研究上的应用初探

以30年生的3个品种的橡胶树为参试材料建立根系模型。测量根系拓扑、分枝规律、连结长度、连结直径和根系分枝角度,将这些数据应用于FracRoot模型,对橡胶树根系分段数量、总长度和生物量进行预测。结果表明,根段的逐渐变细对参数α值有很大影响,FracRoot模型轻微的低估了RRIM600和PR107中根系的分段数量和总长度,高估了GT1分段数量和总长度;过高的估计了所有物种的单一根系总的生物量;过低预测根系的水平分布,而过高的估计了垂直分布。

颈椎病动物模型及其内在分子机制

背景:将临床疾病完全转化为动物模型存在许多问题,但理想的动物模型是进行颈椎病机制研究的前提,因此选择合适的颈椎病动物模型至关重要。目的:详细分析颈椎病动物模型的物种、性别、年龄、颈椎病模型类型及其内在分子机制,探讨如何选择合适的动物模型应用于颈椎病实验研究。方法:应用计算机检索PubMed、Medline、Embase、Web of science、万方、维普和CNKI等数据库,英文检索词为“cervical spondylosis,cervical spondylotic myelopath,cervical spondylotic radiculopathy,cervical spondylosis of vertebral artery type,neck type cervical spondylosis,unbalanced dynamic and static forces,joint injury,neck pain,animal model”,中文检索词为“颈椎病,神经根型颈椎病,脊髓型颈椎病,椎动脉型颈椎病,颈型颈椎病,动静力失衡,关节损伤,颈痛,动物模型”,按照纳入和排除标准对文献进行筛选,最终纳入61篇文献进行综述。结果与结论:大鼠是最常用的动物,雄性大鼠似乎更受欢迎,推荐使用成年前后的动物。根据造模特点可以将颈椎病模型分为脊髓型、神经根型、颈型和其他型,不同造模方法各有优缺点。从已有动物模型的研究出发,总结了颈椎病的分子机制,治疗信号介导核因子κB、磷脂酰肌醇3-激酶/蛋白激酶B、丝裂原激活蛋白激酶等通路调节脊髓、神经根、椎间盘、肌肉等组织的炎症反应、凋亡、自噬等生物学过程,最终延缓颈椎病的进展。部分研究质量较差,与临床契合度不高,未来需要进一步将颈椎病动物模型标准化,制定相关指南,提高研究结果的可信度,为进一步开展人体临床试验奠定坚实的基础。

三维Warren-Root地质模型重正化群方法理论研究

首次利用重正化群方法对三维ＷａｒｅｎＲｏｏｔ模型进行了理论研究，求出其临界导通概率（Ｐｃ）值（０．０４２３）及单方向裂缝临界开启概率（Ｐｆｃ）值（７．１８‰），由此求出其分形维数（Ｄｆ）值（０．８７１）。通过对这些参数的分析，探讨了该模型的意义和适用范围，认为对于有裂缝的碳酸盐岩这样的双重介质系统而言：①只要基质岩块的导通概率超过Ｐｃ值，系统趋于整体连通，有较好的开发潜力；②Ｐｆｃ反映系统中开启裂缝所占比例，只要各方向裂缝开启概率大于Ｐｆｃ值，整个系统趋于导通；③Ｄｆ值较低，反映ＷａｒｅｎＲｏｏｔ模型中裂缝很发育，分形充满程度不高，说明该模型适用于裂缝非常发育地区的致密岩性储集层评价。图３参６（陈志宏摘）

Mechanical analysis of interaction between plant roots and rock and soil mass in slope vegetation

With the help of plant roots, slope vegetation makes the slope soil mass become a composite material of soil and roots, and thus enhances shear strength of the slope soil mass and stability of the slope. However, the related studies at present are still qualitative. In this paper, quantitative analysis of the interaction between roots and soil mass are made. By the analysis of the interaction between herbaceous plant roots including lateral roots of woody plants and rock and soil mass, a mechanical model of the interaction between frictional roots and soil is established, and its correctness is shown. A mechanical model of the interaction between anchorage root, namely, woody plant taproot, and soil is also established. The establishment of the models provides a useful means in quantitative analysis of the interaction between plant roots and soil, and has practical values.

Design and Test Analysis of a Solar Array Root Hinge Drive Assembly

A root hinge drive assembly is preferred in place of the classical viscous damper in a large solar array system.It has advantages including better deployment control and higher reliability.But the traditional single degree of freedom model should be improved.A multiple degrees of freedom dynamics model is presented for the solar arrays deployment to guide the drive assembly design.The established model includes the functions of the torsion springs,the synchronization mechanism and the lock-up impact.A numerical computation method is proposed to solve the dynamics coupling problem.Then considering the drive torque requirement calculated by the proposed model,a root hinge drive assembly is developed based on the reliability engineering design methods,and dual actuators are used as a redundancy design.Pseudo-efficiency is introduced and the major factors influencing the（pseudo-）efficiency of the gear mechanism designed with high reduction ratio are studied for further test data analysis.A ground prototype deployment test is conducted to verify the capacity of the drive assembly.The test device consists of a large-area solar array system and a root hinge drive assembly.The RHDA development time is about 43 s.The theoretical drive torque is compared with the test values which are obtained according to the current data and the reduction efficiency analysis,and the results show that the presented model and the calibration methods are proper enough.

Effects of free-air CO_2 enrichment on adventitious root development of rice under low and normal soil nitrogen levels

Free air CO2 enrichment(FACE) and nitrogen(N) have marked effects on rice root growth,and numerical simulation can explain these effects. To further define the effects of FACE on root growth of rice, an experiment was performed, using the hybrid indica cultivar Xianyou63. The effects of increasing atmospheric CO2 concentration [CO2], 200 μmol mol-1higher than ambient, on the growth of rice adventitious roots were evaluated, with two levels of N: low(LN, 125 kg ha-1) and normal(NN, 250 kg ha-1). The results showed a significant increase in both adventitious root number(ARN) and adventitious root length(ARL) under FACE treatment. The application of nitrogen also increased ARN and ARL, but these increases were smaller than that under FACE treatment. On the basis of the FACE experiment, numerical models for rice adventitious root number and length were constructed with time as the driving factor. The models illustrated the dynamic development of rice adventitious root number and length after transplanting, regulated either by atmospheric [CO2] or by N application.The simulation result was supported by statistical tests comparing experimental data from different years, and the model yields realistic predictions of root growth. These results suggest that the models have strong predictive potential under conditions of atmospheric [CO2] rises in the future.