Continuous Dynamic Rotation Measurements Using a Compact Cold Atom Gyroscope

We present an experimental demonstration of the rotation measurement using a compact cold atom gyroscope. Atom interference fringes are observed in the stationary frame and the rotating frame, respectively. The phase shift and contrast of the interference fringe are experimentally investigated. The results show that the contrast of the interference fringe is well held when the platform is rotated, and the phase shift of the interference fringe is linearly proportional to the rotation rate of the platform. The long-term stability, which is evaluated by the overlapped Allan deviation, is 8.5 × 10^-6 rad/s over the integrating time of 1000s.

Type Synthesis of Two-Degrees-of-Freedom Rotational Parallel Mechanism with Two Continuous Rotational Axes

The two-rotational-degrees-of-freedom（2R） parallel mechanism（PM） with two continuous rotational axes（CRAs） has a simple kinematic model.It is therefore easy to implement trajectory planning,parameter calibration,and motion control,which allows for a variety of application prospects.However,no systematic analysis on structural constraints of the 2R-PM with two CRAs has been performed,and there are only a few types of 2R-PM with two CRAs.Thus,a theory regarding the type synthesis of the 2R-PM with two CRAs is systematically established.First,combining the theories of reciprocal screw and space geometry,the spatial arrangement relationships of the constraint forces applied to the moving platform by the branches are explored,which give the 2R-PM two CRAs.The different distributions of the constraint forces in each branch are also studied.On the basis of the obtained structural constraints of branches,and considering the geometric relationships of constraint forces in each branch,the appropriate kinematic chains are constructed.Through the reasonable configuration of branch kinematic chains corresponding to every structural constraint,a series of new 2R-PMs with two CRAs are finally obtained.

Numerical study on three-dimensional flow field of continuously rotating detonation in a toroidal chamber

Gaseous detonation propagating in a toroidal chamber was numerically studied for hydrogen/oxygen/nitrogen mixtures. The numerical method used is based on the three-dimensional Euler equations with detailed finiterate chemistry. The results show that the calculated streak picture is in qualitative agreement with the picture recorded by a high speed streak camera from published literature. The three-dimensional flow field induced by a continuously rotating detonation was visualized and distinctive features of the rotating detonations were clearly depicted. Owing to the unconfined character of detonation wavelet, a deficit of detonation parameters was observed. Due to the effects of wall geometries, the strength of the outside detonation front is stronger than that of the inside portion. The detonation thus propagates with a constant circular velocity. Numerical simulation also shows three-dimensional rotating detonation structures, which display specific feature of the detonation- shock combined wave. Discrete burning gas pockets are formed due to instability of the discontinuity. It is believed that the present study could give an insight into the interest- ing properties of the continuously rotating detonation, and is thus beneficial to the design of continuous detonation propulsion systems.

Continuous Distillation Experiment with Rotating Packed Bed

旋转的性能与三种包装包装了床(RPB ) 在气压在连续蒸馏条件下面用白酒 / 水答案被调查。平均高严肃因素的效果(尾) ，倒流比率(R) ，和化工物品流动(F) 在上在蒸馏集体转移独立被检验。试验性的结果显示 RPB 的理论单位(NTU ) 的全部的数字与尾， R，和 F 增加了。三种包装，不锈钢(收拾行李的 III )收拾行李的波浪线与约 7.35 公里的一个理论盘子( HETP )的高度等价物有最好的集体转移效率-- 23.58 公里，而不锈钢收拾行李的弄皱的磁盘(收拾行李我)与大约 13.4 mm-48.07 公里的 HETP 有最糟的。关联被开发为包装描述集体转移效率。把试验性的数据与数据作比较由关联计算了，一般水准背离获得了因为分别地，各收拾行李是 0.72% ， 1.98% ，和 2.7% 暗示开发的关联的精确性是合理的。

Modified Omega-K algorithm for processing helicopter-borne frequency modulated continuous waveform rotating synthetic aperture radar data

With appropriate geometry configuration, helicopter- borne rotating synthetic aperture radar （ROSAR） can break through the limitations of monostatic synthetic aperture radar （SAR） on forward-looking imaging. With this capability, ROSAR has extensive potential applications, such as self-navigation and self-landing. Moreover, it has many advantages if combined with the frequency modulated continuous wave （FMCW） technology. A novel geometric configuration and an imaging algorithm for helicopter-borne FMCW-ROSAR are proposed. Firstly, by per- forming the equivalent phase center principle, the separated trans- mitting and receiving antenna system is equalized to the case of system configuration with antenna for both transmitting and receiving signals. Based on this, the accurate two-dimensional spectrum is obtained and the Doppler frequency shift effect in- duced by the continuous motion of the platform during the long pulse duration is compensated. Next, the impacts of the velocity approximation error on the imaging algorithm are analyzed in de- tail, and the system parameters selection and resolution analysis are presented. The well-focused SAR image is then obtained by using the improved Omega-K algorithm incorporating the accurate compensation method for the velocity approximation error. FJnally, correctness of the analysis and effectiveness of the proposed al- gorithm are demonstrated through simulation results.

Particle path tracking method in two- and three-dimensional continuously rotating detonation engines

The particle path tracking method is proposed and used in two-dimensional（2D） and three-dimensional（3D） numerical simulations of continuously rotating detonation engines（CRDEs）. This method is used to analyze the combustion and expansion processes of the fresh particles, and the thermodynamic cycle process of CRDE. In a 3D CRDE flow field, as the radius of the annulus increases, the no-injection area proportion increases, the non-detonation proportion decreases, and the detonation height decreases. The flow field parameters on the 3D mid annulus are different from in the 2D flow field under the same chamber size. The non-detonation proportion in the 3D flow field is less than in the 2D flow field. In the 2D and 3D CRDE, the paths of the flow particles have only a small fluctuation in the circumferential direction. The numerical thermodynamic cycle processes are qualitatively consistent with the three ideal cycle models, and they are right in between the ideal F–J cycle and ideal ZND cycle. The net mechanical work and thermal efficiency are slightly smaller in the 2D simulation than in the 3D simulation. In the 3D CRDE, as the radius of the annulus increases, the net mechanical work is almost constant, and the thermal efficiency increases. The numerical thermal efficiencies are larger than F–J cycle, and much smaller than ZND cycle.

Experimental Research on the Propagation Process of Continuous Rotating Detonation Wave

In order to study the propagation mechanism of continuous rotating detonation wave,the H2/air continuous rotating detonation engine ignited by tangentially installed H2/O2pre-detonation tube is studied experimentally using a tilt slot injector structure.The experimental results show that the stable rotating detonation wave can be gained successfully with the equivalent ratio of 0.93.The propagation frequency and velocity of rotating detonation wave range from 5200 to 5500 Hz and from 1518.5 to 1606.1 m/s,respectively.Three propagation modes,such as rotation,reversal and bifurcation,of detonation wave are verified through the analysis of propagation mechanism of rotating detonation wave.

Comparison and Selection of Arch-Rib Construction Schemes for Continuous Beam arch Composite Bridge of High Speed Railway

The paper summarizes the four different construction schemes based on engineering cases for the arch rib construction of continuous beam-arch composite bridges for high-speed railways.These methods include in-situ assembly,segmental lifting,incremental launching and longitudinal moving,and vertical rotation.The temporary structural designs,process methods,and technological equipment for each construction scheme are described in detail.The advantages and disadvantages of each scheme and its application scope under various conditions are analyzed,and opinions and suggestions for guiding the application of each scheme are proposed.The comparison and selection analyses show that the four arch rib construction schemes have certain applicability under different conditions such as bridge site status,bridge span,and construction environment.With the continuous increase of bridge span and progress of construction technological equipment,the arch rib construction technology is developing towards the overall erection direction.This leads to more obvious technical advantages of the segmental lifting method,incremental launching and longitudinal moving method,and vertical rotation method.Therefore,it is necessary to select the best construction scheme according to the construction status and technical conditions during application.

A comprehensive analysis of the response of the fungal community structure to long-term continuous cropping in three typical upland crops

Certain agricultural management practices are known to affect the soil microbial community structure;however,knowledge of the response of the fungal community structure to the long-term continuous cropping and rotation of soybean,maize and wheat in the same agroecosystem is limited.We assessed the fungal abundance,composition and diversity among soybean rotation,maize rotation and wheat rotation systems and among long-term continuous cropping systems of soybean,maize and wheat as the effect of crop types on fungal community structure.We compared these fungal parameters of same crop between long-term crop rotation and continuous cropping systems as the effect of cropping systems on fungal community structure.The fungal abundance and composition were measured by quantitative real-time PCR and Illumina MiSeq sequencing.The results revealed that long-term continuous soybean cropping increased the soil fungal abundance compared with soybean rotation,and the fungal abundance was decreased in long-term continuous maize cropping compared with maize rotation.The long-term continuous soybean cropping also exhibited increased soil fungal diversity.The variation in the fungal community structure among the three crops was greater than that between long-term continuous cropping and rotation cropping.Mortierella,Guehomyces and Alternaria were the most important contributors to the dissimilarity of the fungal communities between the continuous cropping and rotation cropping of soybean,maize and wheat.There were 11 potential pathogen and 11 potential biocontrol fungi identified,and the relative abundance of most of the potential pathogenic fungi increased during the long-term continuous cropping of all three crops.The relative abundance of most biocontrol fungi increased in long-term continuous soybean cropping but decreased in long-term continuous maize and wheat cropping.Our results indicate that the response of the soil fungal community structure to long-term continuous cropping varies based upon crop types.

Strain data recorded in Xinjiang and their bearing on Tianshan’s uplift/shortening and Tarim basin’s rotation

Based on the continuous strain data recorded in Xinjiang since 1985, we discuss the mechanisms of Tianshan＇ s uplift and Tarim basin＇ s clockwise rotation. The results indicate ： 1 ） The principal - compression directions in Tianshan are nearly NS, and their intersection angles with regional structures and mountains are nearly perpendicular, which is in accordance with Tianshan＇ s uplift and crustal shortening. 2）The principal compressions around Tarim basin tend to facilitate the regional faults＇ left-lateral strike-slip movements and the basin＇ s clockwise rotation. These phenomena of uplift/shortening and rotation are fundamentally the re- suits of India plate＇ s northward push on Euro-Asia plate, and the associated Pamir arc ＇ s rapid northward movement and regional blocks＇ interaction.

The Effect of Crop Rotation on Soil Nematode Community Composition in a Greenhouse

[Objective] The aim was to identify changes in a nematode community in response to crop rotation and to determine the appropriate catch crop for a greenhouse. [Method] The experiment was carried out in a typical 6-year-old greenhouse,in which cucumber crops were cultivated twice each year(in spring and autumn),and catch crops were planted in summer. The total number of nematodes was counted and nematode community indices were calculated after collecting soil samples in different stages. [Result] Total nematode abundance was decreased in the soils of catch crop in contrast with former crops(cucumber crops). The abundance of the nematode community was reduced in the treatment of crop rotation compared to the soils of catch crop. In addition, the number of nematode taxa was significantly reduced by the treatment of crown daisy compared to the treatments of following crops. Crop rotation regulated the functional composition of the nematode community by increasing the omnivores-predators functional group and decreasing the relative abundance of root herbivores. [Conclusion] These results indicate that crop rotation affects the nematode community in abundance, diversity and functional composition of the nematode community and crown daisy can be served as the most appropriate catch crop in the greenhouse.

Influence of rotation system on siderophere-producing microorganism(SPM) in rhizosphere soil of southern China

Soil siderophores are important for crop growth,benefit ferric iron absorption of root,and are affected by cropping patterns.The objective of this study was to evaluate the quantity of siderophores in soil of 2 continuous crop rotation patterns over 30 years in Anren country,China.Quantity and siderophore-producing capability of microorganisms in rice-riceoilseed rape(DDY)rotation and rice-rice(DD)rontinuous cropping rhizosphere soil were tested and analyzed by chrome azurol S method.Isolated strains were used to identify siderophore-producing microorganism(SPM)by PCR amplification and DNA sequencing.Results showed that 9 siderophore-producing bacteria strains were isolated from DDY rhizosphere soil while 7 strains were identified from DD rhizosphere soil.The mean solubility index which representing siderophore-producing capability of strains was 3.05.PCR amplification results indicated that bacterial were the major SPM in soil.This research indicates that crop rotation systems could drive microorganisms to produce siderophores and enrich them in bacterial communities.

种植模式对当归根际土壤真菌群落与功能类群的影响

再植障碍问题限制了当归产业健康发展。为了建立高效种植方式,在甘肃渭源县设置5种种植方式[A:豌豆-小麦-当归;B:豌豆-蒙古黄芪-当归;C:豌豆-马铃薯-当归;D:豌豆-当归-当归(对照);E:豌豆-休耕-当归],采挖期通过Illumina Hisqe 2500高通量测序平台测定了不同种植模式下当归根际土壤真菌ITS1变异区的基因序列,分析不同种植方式对当归根际土壤真菌群落和功能差异性的影响。结果表明:(1)5种种植方式下当归根际真菌多样性差异不大,较对照D处理,A、B、C和E处理的Chao1指数、Ace指数和Shannon指数较低,Simpson指数较高。(2)5种种植方式下当归根际土壤真菌群落隶属于11门167属,其中,子囊菌门(Ascomycota)、被孢菌门(Mortierellomycota)、担子菌亚门(Basidiomycota)和壶菌门(Chytridiomycota)为优势门;被孢霉属(Mortierella)、四枝孢属(Tetracladium)为优势属。(3)冗余度分析发现:在门水平影响土壤真菌群落结构组成的主要因子为速效钾、电导率、pH值,在属水平影响土壤真菌群落结构组成的主要因子为有机质、pH值、二氧化碳呼吸速率。(4)FUNGuild预测表明:植物病原体和木质腐生真菌功能群的相对丰度较高。综上所述,不同作物轮作较当归连作,降低了当归根际土壤真菌群落的相对丰度和多样性,有利于根际土壤真菌群落向有益的方向发展。

AA3连续流动分析仪驱动马达带动转轴旋转模块设计及土壤中总氮测试

针对连续流动分析仪检测土壤中总氮时遇到的问题,研制了驱动马达带动转轴旋转模块.该模块可使混合的样品、试剂和空气保持在合适的温度区间进行中和反应,以利于后期利用连续流动分析仪在最优化条件下对样品进行检测分析,可将总氮的检出限从16.4µg/L降低至10.0µg/L,从而提高连续流动分析仪对样品的分析精度.

基于改进拟连续算法的回转弹仓位置控制

为提高大口径火炮自动装填过程中回转弹仓工作的精确性和鲁棒性,在分析现有拟连续算法相关研究内容的基础上,设计一种全新的改进拟连续控制器对回转弹仓进行位置控制。通过与滑模扰动观测器相结合,新控制器增益不依赖于系统扰动的不确定性边界,且不需引入额外的控制器参数,降低了控制器的设计和调试难度。通过Lyapunov方程验证控制器本身及闭环系统的稳定性。仿真和试验结果表明:新设计的控制器相对于已有拟连续算法具有优越性,在受到不确定时变负载和不确定参数扰动的情况下,新设计的改进控制器在应用于回转弹仓时,在趋近段可以获得更快的收敛速度,减小到位超调量,并在滑动段有效减弱抖振。

荞麦轮作对云南栽培马铃薯根际土壤酶活和微生物的影响

为探讨连作和与苦荞(KQ)轮作对云南省3个马铃薯主栽品种根际土壤酶活性、微生物数量和产量的影响,以马铃薯主栽品种‘合作88’(HZ88)、‘丽薯6号’(LS6H)、‘青薯9号’(QS9H)为试验材料,对不同处理下根际土壤的蔗糖酶、蛋白酶、脲酶、纤维素酶活性和微生物数量以及马铃薯产量、品质进行分析。结果表明,KQ-HZ88、KQ-LS6H、KQ-QS9H轮作处理的马铃薯单株产量分别较HZ88-HZ88、LS6H-LS6H、QS9H-QS9H连作处理显著增加76.32%、80.95%、90.91%,还原糖含量显著降低38.71%、18.42%、21.43%。与3年连作相比,HZ88-KQ-HZ88和KQ-HZ88-KQ、LS6H-KQ-LS6H和KQ-LS6H-KQ、QS9H-KQ-QS9H和KQ-QS9H-KQ轮作处理的土壤蔗糖酶活性分别较HZ88-HZ88-HZ88、LS6H-LS6H-LS6H、QS9H-QS9H-QS9H连作处理显著增加8.54%和14.00%、22.73%和34.25%、18.13%和25.12%;细菌数量显著增加19.05%(P>0.05)和92.86%、75.68%和72.97%、67.11%和73.21%。土壤酶活性及微生物数量的变化可能是引起云南地区马铃薯连作障碍的重要原因之一,轮作可有效改善根际土壤酶活性,增加土壤中有益菌数量,缓解连作障碍。

基于弯型预爆管的煤油燃料旋转爆轰发动机起爆实验研究

为了研究采用弯型预爆管的预爆轰式连续旋转爆轰发动机点火起爆过程和旋转爆轰波的传播特性,设计了H 2/O 2弯型预爆轰管的预爆轰点火装置,进行了预爆轰点火实验,并研究了应用该预爆轰管的煤油/富氧空气旋转爆轰发动机的起爆特性。借助高频动态压力传感器和高速摄影,分别记录了实验过程中的压力信号与流场动态变化过程,分析了旋转爆轰波的起爆过程以及传播特性。实验结果表明:初始爆轰波在到达燃烧室入口后迅速膨胀解耦,形成两个沿相反方向传播的压力波,并且压力峰值迅速衰减;成功起爆后,爆轰波在燃烧室内以双波对撞模态自持传播,每一周期内双波发生对撞的位置不断变化;当煤油质量流量增加时,燃烧室内形成稳定旋转爆轰的时间间隔增加;在稳定工作范围内,提高当量比可以增加爆轰波的平均传播速度。该实验验证了将该弯型预爆管应用于煤油/富氧空气旋转爆轰发动机点火的可行性,进一步揭示了煤油/富氧空气旋转爆轰发动机的起爆过程。

连续梁桥质量转动缠绕索装置振动台试验

为发挥活动墩的抗震潜能,提升连续梁桥纵向整体协同受力效果,基于功能分离与协同受力原理,提出一种质量转动缠绕索装置。以一典型三跨连续梁桥为例,通过以不同地震频谱特性和地震强度的实际地震波作为激励的振动台试验,分析各类地震作用下等墩高模型和不等墩高模型结构关键位置的地震响应的变化规律。从桥墩墩顶加速度响应、位移响应和墩底应变响应等结构关键位置的试验结果可以看出,装置对于增强活动墩参与连续梁桥纵向整体协同受力的效果较为明显,且随着地震动输入强度的增加,装置的协同作用越发凸显。同时,装置的作用效果与装置本身的缠绕圈数、活动墩的墩高等因素有关,设计时需要根据结构墩高的不同确定装置的合理设计参数,以实现装置的最佳应用效果。

广藿香-薄荷轮作和广藿香连作对其品质及其根际土壤微生态的影响

【目的】比较广藿香[Pogostemon cablin(Blanco)Benth.]与薄荷(Mentha haplocalyx Briq.)轮作及广藿香连作对广藿香品质及其根际土壤微生态的影响,为缓解广藿香连作障碍及在生产中的应用提供依据。【方法】以广藿香扦插苗和薄荷苗为试材进行田间试验,共设3个处理:广藿香连作组(连续2年种植广藿香)、薄荷-广藿香轮作组(第1年种植薄荷,采收后第2年种植广藿香)、对照组(第1年不种植作物,采收后第2年在同一块地种植广藿香),在广藿香不同生长时期测定其主要农艺性状、叶片抗氧化酶活性、百秋李醇含量、根际土壤理化性质、微生物数量及酶活性。【结果】广藿香植株生长180 d时,轮作组广藿香主要农艺性状(株高、茎粗、一级分枝数、叶片数、叶绿素含量、叶面积)及百秋李醇含量均显著高于连作组(P<0.05)。轮作组的广藿香叶片过氧化物酶、超氧化物歧化酶活性较连作组分别升高54.23%(P<0.05)、115.71%(P<0.05)。轮作组的广藿香根际土壤理化性质(pH、有机质、有效磷、水解性氮、速效钾)均显著高于连作组;轮作组的土壤细菌数和放线菌数较连作组分别增加98.95%(P<0.05)、71.61%(P<0.05),而轮作组的土壤真菌数量较连作组降低48.86%(P<0.05);轮作组的土壤过氧化物酶、脲酶活性较连作组分别增加827.66%(P<0.05)、655.00%(P<0.05),轮作组的土壤蔗糖酶、多酚氧化酶活性较连作组分别降低44.49%(P<0.05)、28.99%(P<0.05)。【结论】广藿香与薄荷轮作的广藿香农艺性状、百秋李醇含量及土壤微生态指标总体优于广藿香连作的相同指标。