汽车离合器的维修     

黄金艳  王云光 《农机使用与维修》2011,(4):97-97

汽车离合器是依靠摩擦力矩来传递发动机动力的,保证发动机和传动系统平稳而可靠地接合或彻底暂时分离。在汽车机械式传动系统中,应用最广的是摩擦式离合器。它是靠多个摩擦圆盘间产生的摩擦力矩来传递动力的。汽车上常用单片或双片多簧式离合器。单片多簧式离合器的优点是结构简单,工作可靠,调整方便,外形尺寸小,  相似文献   

Comparison of diagnostics techniques in an outbreak of infectious laryngotracheitis from meat chickens     

Crespo R  Woolcock PR  Chin RP  Shivaprasad HL  García M 《Avian diseases》2007,51(4):858-862

Various diagnostics techniques were compared for their ability to detect infectious laryngotracheitis (ILT) during an outbreak in chickens aged between 4 and 21 wk. Gross lesions ranged from excess mucus to accumulation of fibrinonecrotic exudate in the larynx and trachea. Syncytial cells with intranuclear inclusion bodies were found in sinus, conjunctiva, larynx, trachea, lung, and air sac. Virus isolation in chicken embryos was attempted in every case. Negative-stain electron microscopy detected herpesvirus in only 6% of the cases. Yet, isolation of ILT virus in the chorioallantoic membrane was presumed by histology in >20% of the samples and confirmed by fluorescent antibody (FA) in 35% of the embryos inoculated with conjunctivas or tracheas from affected birds. Overall, results from histology and FA tests were highly correlated. FA test has the advantage over histology of being diagnostically specific for ILT virus. Polymerase chain reaction was the most sensitive test and detected the viral DNA even in cases where histology and FA were negative. ILT virus DNA was quantified by real-time polymerase chain reaction (Re-Ti ILTV). Histologic and FA results from larynx and trachea were negative if the concentration of the viral DNA was < or =4 of log10. A viral DNA concentration higher than log10 4, as determined by Re-Ti ILTV, was required for clinical ILT to be manifested.  相似文献   

Effect of type I interferons on the expression of feline leukaemia virus     

Collado VM  Gómez-Lucía E  Tejerizo G  Miró G  Escolar E  Martín S  Doménech A 《Veterinary microbiology》2007,123(1-3):180-186

  相似文献   

Evolution of wheat architecture,physiology, and metabolism during domestication and further cultivation: Lessons for crop improvement     

Arturs Katamadze  Omar Vergara-Díaz  Estefanía Uberegui  Ander Yoldi-Achalandabaso  José Luis Araus  Rubén Vicente 《作物学报(英文版)》2023,(4):1080-1096

In recent decades, genetic advances in yield improvement in the major cereal crops, including wheat, has stagnated or proceeded at a slower rate than is required to meet future global food demand, particularly in the face of climate change. To reverse this situation, and in view of the future climate scenario, there is a need to increase the genetic diversity of wheat to increase its productivity, quality, stability, and adaptation to local agro-environments. The abundant genetic resources and l...  相似文献   

西瓜种质资源的研究进展     

韩金星  周林  黄金艳  覃斯华  洪日新  何毅  李文信  李天艳  樊学军 《长江蔬菜》2009,(10)

对国内外的西瓜种质资源的收集、鉴定利用和种质资源创新等方面进行阐述.总结国内外西瓜种质资源研究上取得的成就,并对我国西瓜种质资源存在的问题提出建议.  相似文献   

桂粤地区西瓜甜瓜生产现状、存在的问题及其对策   总被引：1，自引：0，他引：1  

李文信  黄金艳  覃斯华  何毅  洪日新  李天艳  樊学军 《中国瓜菜》2009,22(2)

<正>广西和广东为华南西瓜甜瓜冬春季和秋延后栽培面积较大的省区,年总栽培面积9万hm2,其中广西6.33万hm2,广东2.67万hm2。1生产现状1.1主要产区和种植面积广西主产区分布在南宁、百色、梧州、北海、崇左等5市,年总栽培面积5.334万hm2,其中西瓜面积4.684万hm2,甜瓜0.65万hm2,占全区总面积的80%以上。南宁产区有武鸣县锣圩、宁武、马头、两江、罗波、里建镇,横县校椅镇和辖区的吴圩、苏圩、延安、那陈、蒲庙、大塘、伶俐、坛洛、双定、石埠、  相似文献   

Fluorescence, browning index, and color in infant formulas during storage     

Ferrer E  Alegría A  Farré R  Clemente G  Calvo C 《Journal of agricultural and food chemistry》2005,53(12):4911-4917

Free and total fluorescent compounds, browning index, and color formation were measured in milk-based powdered infant formulas (IF) during 2 years of storage at 20 and 37 degrees C. The excitation spectra from 415 nm emission show three peaks (ex lambda1 = 270 nm, lambda2 = 325/315 nm, lambda3 = 350 nm) and from 347 nm excitation two emission peaks (415 and 520 nm), and no wavelength shifts were observed. Temperature and time of storage exert in general no significant effect on the development of fluorescence emission intensity and browning index. However, an important increase in pentodilysine was recorded-probably because of the iron and ascorbic acid contents of the samples-as well as in browning index in adapted IF. In both IF a color increase (deltaE) throughout storage was observed, this increase being greater in samples stored at 37 degrees C than in those stored at 20 degrees C. The increase in color with time fitted a linear regression model. Color appeared to be an indicator of sufficient sensitivity to measure the effect of temperature or storage time.  相似文献   

Construction of Genetic Linkage Map of Bread Wheat （Triticum aestivum L.） Using an Intervarietal Cross and QTL Map for Spike Related Traits     

Most often a genetic linkage map is prepared using populations obtained from two highly diverse genotypes.However  the markers from such a map may not be useful in a breeding program as these markers may not be polymorphie among the varieties used in breeding.…… 《分子植物育种》2007,5(2):219-220

Most often a genetic linkage map is prepared using populations obtained from two highly diverse genotypes. However, the markers from such a map may not be useful in a breeding program as these markers may not be polymorphic among the varieties used in breeding. For the past nine years, intraspecific maps have been gaining importance and such maps based on Swiss （PaiUard et al., 2003）, Japanese （Suenaga et al., 2005）, Australian （Chaimcrs et al., 2001） wheat varieties arc available. A map based on Indian wheat varieties however has not been reported. We constructed a genetic linkage map based on a cross between two Indian bread wheat （Triticum aestivum L.） varieties, Sonalika and Kalyansona. One hundred and fifty F2 individuals were analyzed for arbitrarilyprimed polymerase Chain reaction （AP-PCR）, random amplified polymorphic DNA （RAPD）, inter simple sequence repeats （ISSR）, Sequence Tagged Microsatelhte Sites （STMS）, Amplified Fragment Length Polymorphism （AFLP） markers, seed storage proteins and known genes. A linkage map was constructed consisting of 236 markers and spanning a distance of 3 639 cM with 1 211.2 cM for A genome, 1 669.2 cM for B genome, 192.4 cM for D genome and 566.2 cM for unassigned groups,  相似文献   

Enzyme-mediated solvent extraction of carotenoids from marigold flower (Tagetes erecta)   总被引：2，自引：0，他引：2  

Barzana E  Rubio D  Santamaria RI  Garcia-Correa O  Garcia F  Ridaura Sanz VE  López-Munguía A 《Journal of agricultural and food chemistry》2002,50(16):4491-4496

Marigold flowers are the most important source of carotenoids for application in the food industry. However, the extraction gives almost 50% losses of the carotenoids depending on conditions for silaging, drying, and solvent extraction. In the past decades, macerating enzymes have been successfully applied to improve the extraction yield of valued compounds from natural products. In this work, an alternative extraction process for carotenoids is proposed, consisting of a simultaneous enzymatic treatment and solvent extraction. The proposed process employs milled fresh flowers directly as raw material, eliminating the inefficient silage and drying operations as well as the generation of hard to deal with aqueous effluents present in traditional processes. The process developed was tested at the 80 L scale, where under optimal conditions a carotenoid recovery yield of 97% was obtained.  相似文献   

冬播麦区Glu-1和Glu-3位点变异及1B/1R易位与小麦加工品质性状的关系   总被引：22，自引：3，他引：22  

刘丽  阎俊  张艳  何中虎  Pea R.J.  张立平 《中国农业科学》2005,38(10):1944-1950

 贮藏蛋白组成是决定小麦加工品质的重要因素。本文调查了我国冬播麦区251份主栽品种和高代品系的高分子量麦谷蛋白亚基（HMW-GS）、低分子量麦谷蛋白亚基（LMW-GS）和1B/1R易位的分布状况，研究了它们与加工品质性状的关系。结果表明，品质较差的HMW-GS N、7+9、2+12和LMW-GS Glu-A3a与Glu-B3j（1B/1R易位）在冬播麦区分布较广，频率分别为39.4%、45.0%、59.8%、37.1%和44.6%。HMW-GS和LMW-GS等位变异对籽粒蛋白质含量影响较小，对SDS沉降值、和面时间与耐揉性的加性和互作效应达1%的显著水平。按位点对加工品质性状的贡献大小，Glu-D1>Glu-B3>Glu-B1>Glu-A3>Glu-A1；就单个亚基而言，Glu-A1位点，1>2*>N；Glu-B1位点，7+8>14+15>7+9；Glu-D1位点，5+10>4+12>2+12；Glu-A3位点，Glu-A3d>Glu-A3a>Glu-A3c>Glu-A3e，Glu-B3位点； Glu-B3d>Glu-B3b>Glu-B3f >Glu-B3j。1B/1R易位对SDS沉降值、和面时间和耐揉性等加工品质性状有显著负面效应。通过选择优质高低分子量麦谷蛋白亚基和淘汰1B/1R易位系，将有助于提高我国小麦的面筋质量。  相似文献