一类挖坑机械钻头横向振动系统的最优控制问题   总被引：1，自引：1，他引：0  

孟庆华  于建国  鲍春雨 《森林工程》2005,21(5):25-26

建立了一类挖坑机械钻头横向振动系统的数学模型,并以阻尼函数作为控制变量,研究了该系统的最优控制问题,得出了两个定理。  相似文献   

Fine structure of the canal neuromasts of the lateral line system in the adult zebrafish          下载免费PDF全文

R. Laurà  F. Abbate  G. P. Germanà  G. Montalbano  A. Germanà  M. Levanti 《Anatomia, histologia, embryologia》2018,47(4):322-329

The mechanosensory lateral line system of fish is responsible for several functions such as balance, hearing, and orientation in water flow and is formed by neuromast receptor organs distributed on head, trunk and tail. Superficial and canal neuromasts can be distinguished for localization and morphological differences. Several information is present regarding the superficial neuromasts of zebrafish and other teleosts especially during larval and juvenile stages, while not as numerous data are so far available about the ultrastructural characteristics of the canal neuromasts in adult zebrafish. Therefore, the aim of this study was to investigate by transmission electron microscopy the ultrastructural aspects of cells present in the canal neuromasts. Besides the typical cellular aspects of the neuromast, different cellular types of hair cells were observed that could be identified as developing hair cells during the physiological turnover. The knowledge of the observed cellular types of the canal neuromasts and their origin could give a contribution to studies carried out on adult zebrafish used as model in neurological and non‐neurological damages, such as deafness and vestibular disorders.  相似文献   

Development of Nucleic Acid Lateral Flow Immunoassay Detection Method for Foot-and-mouth Disease Virus     

GONG Zhen-li  JIANG Tao  QI Shu-yun  CHEN Guo-dong  LIU Yan-hong  LI Yong 《中国畜牧兽医》2015,42(9):2292-2297

In this article, through the combination of nucleic acid probes and immune chromatography, a simple, sensitive and specific detection system——nucleic acid lateral flow immunoassay (NALFIA) for amplifing foot-and-mouth disease virus (FMDV) 3D RT-PCR products was established.An ultrasensitive nucleic acid biosensor (NAB) based on streptavidin-labeled gold nanoparticles dual labels and lateral flow strip biosensor (LFSB) were used in this system.The biotinylated goat anti-rabbit IgG was marked to the NC membrane as the alleged strip and the anti-digoxin antibody was labeled to the NC membrane to capture the digoxin probe.After assemblying gold-labeled strip and detecting RT-PCR products, the detection limit of NALFIA was 0.3×10^-3 to 3×10^-3 μg/μL.The NALFIA was compared with agar gel electrophoresis analysis, the results showed that the sensitivity of NALFIA was higher than agar gel electrophoresis.There was an excellent agreement between the two methods.NALFIA was a method with high sensitive, low cost and short time.In conclusion, this method provided a good alternative to detect FMDV.  相似文献   

不同花生品种侧枝发育动态与产量性状研究   总被引：1，自引：0，他引：1  

王小纯  汤丰收  张新友  孙贯升  潘中耀 《华北农学报》2002,17(1):100-104

花生一级侧枝发育具有不均衡性。第一、二对侧枝出现早，伸长快，其他一级侧枝出现晚，伸长慢。86036－26－1第一、二对侧枝发育相对较早，而其他一级侧枝发育较晚；海花1号和豫花1号第一、二对发育相对较晚，而其他一级发育较快；豫花7号和鲁花9号居中。海花1号一级侧枝及第一对侧枝的二级侧枝数最多，86036－26－1的一级侧枝数及第一对侧枝的二级侧枝数量少。在花针期之前第一对侧枝的伸长与主茎基本同步；花针期之后，第一对侧枝伸长速度超过主茎。86036－26－1的一级侧枝长及株高居首位。86036－26－1第一、二对侧枝饱果率，产量居第一，豫花7号居第二。海花1号虽然荚果数较多，但第一、二对侧枝孢果率较低，产量也较低；鲁花9号居中。  相似文献   

Approximate Estimate of Lateral Deflection for Rigid Frame and Frame-Shear Wall Structure Systems     

《保鲜与加工》1997,(6):86-92

This paper expounds the engineering significance of deliberating a method of approximate calculation,and has a discussion on lateral deflection of frame and frame_shear wall structures.  相似文献   

均匀坡下微灌毛管水力设计的平均水头法     

王金如 《节水灌溉》1992,(3)

“平水头法”是均匀坡下微灌毛管水力设计中一种简单易行的方法。该方法根据流量指数x和允许压力偏差率在特定范围内灌水器平均流量所对应的压力与平均(设计)压力近似相等的原理,建立端压与均压间的关系式,以压力设计结果代替流量设计结果。通过相对误差分析,证明了这种方法在实际应用中的可行性。  相似文献   

棉花幼苗侧根发生的化学诱导研究 Ⅲ.Ca~(2+)对棉花幼苗侧根发生和根系IAA含量的影响研究初报     

李召虎  何钟佩  李丕明 《中国农业大学学报》1991,(Z1):19-20

清水或 DPC 200ppm 溶液浸种培养的棉花幼苗在移栽时用含 Ca~(2+)30ppm 的 CaCl_2溶液漫根2小时处理,栽后8天观察发现,两种浸种方式,Ca~(2+)均能促进棉苗侧根的发生,并提高根系 IAA 含量。但 Ca~(2+)处理 DPC 降低根对棉酚含量的效应无明显影响。上述试验结果显示出 Ca~(2+)与诱导棉苗侧根发生和调节根系 IAA 水平之间存在着某些内在的联系,这可能涉及到 Ca~(2+)·CaM系统(胞内第二信使系统)与植物激素效应之间的关系。  相似文献   

Flowering-pattern and yield components at inflorescence nodes of snap bean as affected by irrigation and plant density     

Craighton S. Mauk  Patrick J. Breen  Harry J. Mack 《Scientia Horticulturae》1984,23(1):9-19

This paper reports the results of a 2 × 2 factorial experiment on bush snap beans ‘Oregon 1604’. The treatments were 2 contrasted irrigation regimes and 2 contrasted plant densities, and were applied in 1978 and repeated in 1979. Data were collected on the number of flowers and pods, and pod size, at each node of the terminal inflorescence (6-T) of the main stem, and at each node of the oldest inflorescence (2-A) at Node 2. High and low plant densities were 45 and 18 plants m^?2 in 1978 and 54 and 33 plants m^?2 in 1979. High temperatures, frequently above 32°C, prevailed during bloom and pod development in 1978, but for the most part occurred only during the week prior to bloom in 1979. Inflorescences 6-T and 2-A usually formed 4 and 3 RN's, respectively, in 1978 and 3 and 2 RN's in 1979. The flowers at the proximal nodes of each inflorescence all opened within a few days of one another (duration of flowering at proximal nodes between 3 and 5 days); the flowering-periods of adjacent nodes overlapped, and the flowering period increased acropetally within the inflorescence (duration of flowering at distal nodes between 7 and 13 days). In general, number of flowers, pods formed, pods harvested and percent set decreased acropetally within each inflorescence. The rate of acropetal decline was lessened by high irrigation or low plant density. In both years, high irrigation increased the percent set of all RN's of the 2-A inflorescences, but few other consistent effects between years were observed. The 2 most proximal RN's together produced 93% or more of the yield of each inflorescence. High irrigation significantly increased the total number of pods harvested from these RN's of inflorescences 6-T and 2-A, and low density had a similar effect on 2-A.  相似文献   

European eel distribution and body condition in a river floodplain: effect of longitudinal and lateral connectivity     

E. Lasne  A. Acou  A. Vila‐Gispert  P. Laffaille 《Ecology of Freshwater Fish》2008,17(4):567-576

Abstract – We studied eel population characteristics (size classes, densities and body condition) in the lower Loire River floodplain (France) to evaluate the effects of longitudinal and lateral gradients. A total of 36 sites were electrofished in June 2005. The sites were grouped first into three river segments according to the distance inland corresponding to a longitudinal gradient and secondly into three lateral connectivity categories. Results indicate that small eels, especially those ≤300 mm, were very abundant downstream but density rapidly decreased upstream. In addition, eels ≤150 mm tended to be most abundant in connected waterbodies. Conversely, the distribution of larger eels was quite uniform across both dimensions. Eel condition decreased upstream. In parallel, in downstream river segment, eels had a lower condition in disconnected waterbodies than in connected ones. Eel specialists still have only a longitudinal perception of eel habitat. Our results suggest that lateral gradients should be also taken into consideration.  相似文献   

真空堆载联合预压法在某工程中的应用分析   总被引：1，自引：0，他引：1  

王华敬  刘福臣  杨庆刚  张瑞宝 《山东农业大学学报(自然科学版)》2004,35(3):442-445

本文通过对某工程孔隙水压力及水平位移资料的观测，分析了通过真空一堆载联合预压法加固软上地基，土颗粒所受侧压力、渗流力、抗剪力的变化，揭示了真空一堆载联合预压法在地基水平位移方面的相互作用．以及地下水位的变化对其加固效果的影响。  相似文献