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1.
本文根据具体机器动作协调性要求及其具体空间几何条件,采用了摆动从动件盘形凸轮机构。其摆杆推程在O°~52°及52°~62°范围内分别采用了等加速——等速合理拼接运动规律。回程在62°~153°范围内采用了正弦加速度运动规律。用极坐标矢量分析法建立方程、微分,通过电脑程序计算,设计制造出凸轮轮廓,用于禾苗移植机的擒纵机构处,完全符合生产要求,获得了理想的效果。 相似文献
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Field studies were undertaken to explore the weed management strategies for transplanted and direct wet-seeded rice in the Dera Ismail Khan district of North-west Frontier Province, Pakistan. The experimental design was a randomized complete block with a split plot arrangement. The main plots consisted of two planting techniques (transplantation and direct seeding), while weed control practises assigned to the subplots included the use of the granular herbicide Sunstar 15WG (ethoxy sulfuron), Machete 60EC (butachlor), conventional hand weeding, and the weedy check (untreated control). Data were recorded on weed dynamics and the agronomic parameters of the rice crop. Economic analyses on the data were also run. The weed density and biomass were lower in the transplantation plots than the direct-seeding plots. The herbicides ethoxy sulfuron and butachlor reduced the density over the weedy check, with a density comparable to hand weeding in 2002, but slightly higher in 2003. As a result of weed management by hand weeding and herbicides, the paddy yield and its components were significantly higher for the transplanted method compared to the direct-seeded method. The comparable yield of herbicides with hand weeding offers an option for the use of herbicides as an alternative management tool. In light of our findings, it is concluded that for good economic returns, rice crops may be transplanted rather than direct-seeded. The herbicides ethoxy sulfuron and butachlor offer a weed control cover comparable with hand weeding under the transplantation method, while butachlor is good for controlling weeds even under the direct-seeded conditions in the agroclimatic conditions of the area. 相似文献
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[目的]探索软枣猕猴桃试管苗移栽后的最宜生长条件,提高成活率,缩短成活时间。[方法]通过测试不同炼苗季节、预处理方法、栽培基质、温度、湿度、光照对试管苗成活、移栽效果影响,得出最佳移栽炼苗程序。[结果]将生长健壮,苗高5cm以上的组培苗移至室温光照2000-3000lx,10h/d的栽培条件下经4d炼苗后,清水洗苗,蘸生根粉移栽至沙土∶黄棕壤∶腐叶土∶园土(1∶1∶1∶1)的基质中盆栽、套袋后置于棚高50cm的小拱棚内,拉2层遮阴网(透光率40-50%,温度20-24℃,土壤含水量80-90%)培养出的幼苗,成活率高达92%,叶数7,整体生长整齐,是软枣猕猴桃最佳驯化移栽方式。[结论]实验所得方法可为大田生产提供基础,极大程度上提高移栽成活率,缩短成活时间。 相似文献
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- 1. Nubbins from 12 coral species were transplanted onto dead giant clam shells at three sites in a lagoon near Bolinao, north‐western Philippines. Transplants were attached using three types of adhesives: cyanoacrylate glue (SG), epoxy putty (EP) and marine epoxy (ME) and were monitored over five months for detachment, in situ mortality and natural self‐attachment by tissue growth.
- 2. Corals attached with SG showed a significantly higher rate of detachment (logrank test) than those attached with either EP or ME (P<0.001 in each case). Also, those attached with EP showed a higher rate of detachment than corals attached with ME (logrank=6.46, P<0.05).
- 3. ANOVA (P>0.05) and survival analysis (logrank=2.85, P>0.05) showed no among‐adhesives differences in in situ mortality. Among the species used, Porites cylindrica, Pavona frondifera, Heliopora coerulea and Porites rus had the highest survivorship with 82%, 80%, 76% and 73%, respectively, of nubbins alive at the end of the experiment and also displayed the highest cumulative rates of self‐attachment. Species with the lowest survival rates included Acropora muricata and four pocilloporids.
- 4. Although there was no significant difference in the number of self‐attaching transplants among the adhesives, corals transplanted using ME and EP self‐attached earlier than those transplanted using SG (logrank=11.19, P<0.01).
- 5. Results from this study highlight the importance of selecting the appropriate means of attaching corals to substrates and carefully considering species‐specific traits of candidate corals for transplantation.
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上海大树移植的本底土质量调查与评价 总被引:1,自引:0,他引:1
对上海13个区共450个大树移植的本底土的质量进行了调查。结果表明:土壤有机质含量达标率为74.33%:容重达标率为76.45%;通气孔隙度达标率为57.33%;土壤呈碱性和强碱性;离子总浓度大多正常。本底土质量总体较差.尤其是行道树的大树移植本底土质量更差,不能完全满足移植大树的恢复生长。针对存在的问题,通过添加富含有机质的酸性介质、敷设通气管等方式改良土壤理化性质,确保上海大树移栽的成功。 相似文献