植物动力2003在核桃嫁接技术中的应用

通过试验植物动力2003对核桃嫁接后期影响,主要包括对嫁接后菌木生长量和嫁接成活率的影响.总结出在核桃嫁接后喷施浓度为1.0‰的植物动力2003营养液,可明显提高苗木生长量的同时也可提高嫁接成活率.     

The influence of parasitism on fish population success

Abstract The influence of parasitism on first‐year growth and recruitment success of two cyprinid species in the Yorkshire Ouse catchment, England, was investigated using a 14‐year dataset. This study demonstrated a significant role of parasitism in growth and recruitment success of roach, Rutilus rutilus (L.), and European chub, Squalius cephalus (L.) populations. Muscle infections by Bucephalus polymorphus Baer (Digenea), Myxobolus pseudodispar Gorbunova (Myxozoa) and Myxobolus pfeifferi Thélohan were considered important, with significant relationships between these parasites and year‐class strength and age‐0 fish length. Other parasites, such as Phyllodistomum sp. and Goussia sp., were implicated in host success to a lesser extent. Parasitism may be a major factor in recruitment and account for a high proportion of the variation in year‐class strength, although this varied among locations.     

基于SolidWorks的渐开线齿轮绘制方法研究

Solidworks是目前国内主流的3D机械设计软件,主要探讨了如何使用Solidworks软件绘制渐开线齿轮,以开拓新的设计思路,提高设计效率,为企业赢得时间和客户。     

Yield,nutritive value and silage fermentation of kura clover‐reed canarygrass and lucerne herbages in northern USA

Excellent winter hardiness, persistence and nutritive value of both kura clover (Trifolium ambiguum M. Bieb.) and reed canarygrass (Phalaris arundinacea L.) suggest that intercropping these species could substitute for lucerne (Medicago sativa L.). The dry matter (DM) yield and nutritive value of herbage, and silage characteristics of kura clover‐reed canarygrass (KC‐RCG) herbage, were compared to those of lucerne over two growth cycles near Arlington, WI, USA. First and second growths of lucerne and KC‐RCG herbage were sampled four times at 1‐week intervals and ensiled for 100 d. Yield of DM of the KC‐RCG was 0·23–0·57 greater than that of lucerne on sampling dates in the first growth cycle, with no differences in DM yield in the second growth cycle. The pH of lucerne silage was lower than that of KC‐RCG silage in the first growth, and the opposite occurred in second growth, which was attributed to maturity differences and the proportion of kura clover in the mixture. Lactate concentration was lower in KC‐RCG than lucerne silages in both growth cycles. The lucerne and KC‐RCG silages had similar in vitro DM digestibility except for the final sampling date in the first growth cycle when neutral‐detergent fibre concentration of KC‐RCG herbage exceeded 550 g kg^?1 DM. Crude protein concentration was greater in lucerne silage than in KC‐RCG silage in both growth cycles. Overall, differences in nutritive value and silage fermentation between the two herbages were minimal across growth cycles. These results suggest that a KC‐RCG sward is a viable alternative to lucerne in northern environments of the USA where lucerne production may be limited by winter injury or edaphic factors.     

4LZ-2.0型稻麦联合收获机割台框架有限元模态分析

割台框架的振动稳定性直接影响割刀切割时的正确位置,影响谷物的收获质量。为此,针对4LZ-2.0型稻麦联合收获机割台框架,在Solidworks中建立其三维模型,并将该模型导入ABAQUS有限元分析软件建立有限元模型。通过模态分析,得到了割台框架的前10阶固有频率和振型。通过对模态参数的分析,了解了割台框架的振动形式以及在激励频率作用下该结构的薄弱环节,为框架结构的改进提供了理论依据。     

Response of Mediterranean Tall Fescue Cultivars to Contrasting Agricultural Environments and Implications for Selection

Extensive livestock is a basic socio‐economic feature of the Mediterranean region whose environmental and economic sustainability depends on the ability of forage resources to withstand climatically stressful conditions. Perennial forages such as tall fescue can be a valuable alternative to annuals, if they can survive across successive summer droughts. Three‐year dry matter yield and plant survival of five cultivars of Mediterranean‐type tall fescue were evaluated in six sites of Algeria, France, Italy, Morocco and Portugal, with the following objectives: (i) modelling adaptive responses and targeting cultivars as a function of environmental factors associated with genotype × location interaction; and (ii) defining plant ideotypes, adaptation strategies and opportunities for international co‐operation for regional breeding programmes. Site mean yield and winter temperatures were positively correlated, whereas sward persistence was positively correlated to lower site heat and drought stress. Cultivar adaptation was adequately modelled by factorial regression as a function of site spring–summer (April–September) drought stress (long‐term potential evapotranspiration minus actual water available) for yield, and annual drought stress for final persistence. Specific‐adaptation responses to high‐ or low‐stress environments emerged which were consistent with drought‐stress levels of cultivar selection environments. However, the wide‐adaptation response of cultivar Flecha suggested that breeding for wide adaptation can be feasible.     

基于Solidworks的原木吊装桥式起重机桥架结构研究

原木吊装桥式起重机是林业生产过程中木材堆场的重要起重机械,而对其结构进行分析和评定是原木吊装起重机林业生产过程中重要的一环。利用Solidworks软件完成某型桥式起重机桥架结构的三维建模,通过Solidworks Simulation插件对桥式起重机受力情况进行了有限元仿真分析,得到了桥架结构的应力和位移云图,且仿真结果和一般传统力学解析计算所得结果相同。结果表明:基于Solidworks软件的三维有限元分析,可以快速可靠地得到原木吊装桥式起重机桥架结构受力变化结果,为快速分析此类林业机械结构,评定结构方案是否合理提供了方法。     

Influence of capture method, habitat quality and individual traits on blood parameters of free-ranging lace monitors (Varanus varius)

OBJECTIVE The aims of this study were to determine baseline reference intervals for haematological and serum biochemical parameters in lace monitors, and to examine whether such values were influenced by capture method, expected differences in habitat food resource availability and a lizard's body size and body condition. METHODS Thirty-three wild Victorian lace monitors (Varanus varius) of unknown age and sex were captured by noose pole or aluminium box trap from Cape Conran in East Gippsland, Victoria, Australia. RESULTS No statistical differences between the two capture methods were noted for haematology. There was a significant difference in the serum glucose concentrations between the two methods of capture (higher concentration in box-trapped animals) because of a physiological response to capture stress. Habitat food quality did not appear to influence haematology or serum biochemistry. The packed cell volume (PCV) for the lace monitors was 0.29-0.43 L/L. Lymphocytes were identified as the most common leucocyte. The haemoprotozoan parasite, Haemogregarina varanicola, was found in all 33 blood samples. No correlation could be made between parasite burden and PCV, serum globulins or serum proteins, but animals in poor body condition were more likely to harbour large numbers of parasites. CONCLUSION The results of this study may be used as a basis for evaluating health in lace monitors.     

植物动力2003在玉米及甜瓜上的试验

对植物动力2003(PP2003)在玉米及甜瓜上的使用时间、剂量及使用效果进行了研究。结果表明,玉米在苗期3叶展和拔节期叶面喷施PP2003,能提高玉米单株产量,增加千粒重,较CK(喷等量清水)增产8.7%～12.1%,投入产出比为1∶3.5;甜瓜在苗期2～3叶展和开花前期叶面喷施PP2003,能提高单株产量,甜度也略有增加,较CK增产4.0%～13.1%,投入产出比为1∶5.1;t测验值均达显著或极显著水平。