共查询到20条相似文献，搜索用时 156 毫秒
1.
南美斑潜蝇发生危害的特点观察 总被引：1，自引：0，他引：1
南美斑潜蝇是从国外传入的一重要害虫，已在国内数省发生，并对蔬菜和花卉生产造成了严重损失．通过室内研究和野外调查，初步掌握了南美斑潜蝇在莱阳一带发生危害规律和各个虫态的危害特点，发现不同寄主植物被幼虫危害后的症状有差异，化蛹部位在不同寄主植物上的分布也不一样．成虫在6月中上旬有个日活动高峰期，为5：30～7：30． 相似文献
2.
3.
温室白粉虱的发生规律及无公害综合防治对策 总被引：1，自引：0，他引：1
介绍了目前温室白粉虱在我国种植业中的发生传播规律及其对寄主植物的主要危害特点,探求其发生日益严重的成因,并结合无公害生产的操作标准及国内防治温室白粉虱的最新研究成果,提出了进行农业、生物、物理和化学四位一体的综合防治对策. 相似文献
4.
通过已感土壤根结线虫病的四季豆田间取样研究 ,结果表明 :危害四季豆生产的土壤根结线虫居群为南方根结线虫 (M .incognita)种 ;造成四季豆感病的直接原因是四季豆属于南方根结线虫的寄主植物 相似文献
5.
咖啡灭字虎天牛是危害咖啡树的重大害虫,从本世纪初以来,国内外对该虫做了许多研究、这些研究包括生活史、取食危害习性、寄主植物、化学防治、生物防治等方面.与农林害虫相比,对咖啡灭字虎天牛的研究工作仍相当落后.到目前为止,人们对该虫的自然种群数量变动规律及其发生机制还不清楚.今后加强这方面的研究,对于该虫的综合治理具有重大意义. 相似文献
6.
1 调查目的美洲斑潜蝇 (LiriomyzasativaeBlanchard) ,是近年来危害日趋严重的一种害虫 ,农业部已将其列为全国植物检疫对象进行严格管理。据滨州市农技站调查 ,全市受害西瓜面积达 36 5 0公顷 ,受害严重而枯死的达4 0 0公顷。为了分析造成危害的原因 ,提出合理的防治措施 ,我校生物科技小组对我县四镇的西瓜 5 0公顷进行了调查研究。2 调查内容2 .1 形态特征 美洲斑潜蝇是变态性害虫 ,每个生育周期要历经卵、幼虫、蛹、成虫四种形态发育阶段。2 .1.1 卵 :椭圆形 ,乳白色 ,直径 0 .2～ 0 .3毫米。2 .1.2 幼虫 :浅黄色 ,蛆形 ,后气门… 相似文献
7.
固原地区林木主要害虫分布及发生特点 总被引：2，自引：0，他引：2
李英武 《宁夏师范学院学报》2001,22(6):37-40
在调查宁夏固原地区六县一局9种主要林木害虫的基础上，通过对其分布区域、发生率、寄主植物种类、危害特性及天敌状况的分析研究，总结出它们在固原地区分布发生的特点及存在的成因，为今后的防治工作提供必要的科学依据。 相似文献
8.
9.
10.
不同贮藏温度对南美白对虾黑变的影响 总被引：1，自引：0，他引：1
在低温条件下,微生物的生长会受到抑制,虾体内各种反应酶活力也处于一个较低的水平,能够在一定程度上维持对虾捕获时的品质.通过测定细菌总数和K值等生化指标,结合对南美白对虾的感官评价,对不同贮藏温度下南美白对虾的黑变进行研究.微生物增长、总挥发性盐基氮(TVBN)和K值变化与南美白对虾黑变的关系显示,南美白对虾在0℃、4℃、8℃条件下较适宜贮藏,时间分别不能超过36h、24h和12h. 相似文献
11.
在田间测定了几种杀虫剂对美洲斑潜蝇的防治效果。结果表明:在供试剂量下,1.8%阿巴丁EC和0.2%阿维虫清EC防效较好,药后10天分别为91.10%和87.90%,其次为25%阿克泰水分散剂、48%乐斯本EC和20%杀灭菊酯EC,40%氧化乐果EC防效较低,药后10天仅为46.53%。 相似文献
12.
目的：观察不同剂量辛伐他汀对急性心肌梗死患者近期疗效与安全性。方法：将116例急性心肌梗死患者在常规治疗基础上（包括溶栓药物、硝酸酯类药物、血管紧张素转换酶抑制剂、8受体阻滞剂、阿司匹林、低分子肝素），随机分为常规剂量组：辛伐他汀20mg，每晚1次；高剂量组：辛伐他汀40mg，每晚1次。两组均于急性心肌梗死发病后24h内开始用药，观察30d内主要心血管事件联合终点。结果：治疗30d两组比较，高剂量组明显减少心血管事件联合终点：所有原因死亡，心肌再梗死，不稳定心绞痛，卒中（P〈0．05）。结论：对于急性心肌梗死患者，大剂量辛伐他汀在降低主要心血管事件方面的作用优于常规剂量辛伐他汀，且具有良好的安全性。 相似文献
13.
油橄榄叶提取物对铅中毒小鼠脑中单胺氧化酶活性的影响 总被引：1，自引：0，他引：1
王昱 《绵阳师范学院学报》2012,31(2):67-69
目的：探讨油橄榄叶提取物（OLE）对铅中毒小鼠脑中单胺氧化酶（MAO）活性的影响。方法：选健康小鼠,每日灌胃醋酸铅溶液的同时灌胃不同剂量的OLE进行治疗,连续用药30 d,用比色法检测脑中MAO活性的变化。结果：与正常对照组相比,模型对照组和OLE治疗组小鼠脑中MAO活性明显升高。但小鼠灌胃OLE后脑中MAO的活性与模型对照组相比,明显降低。结论：OLE对铅中毒小鼠脑中MAO活性的增强具有抑制作用。 相似文献
14.
Agneta Ljung-Djärf Lisbeth Åberg-Bengtsson Torgny Ottosson Dennis Beach 《Environmental Education Research》2015,21(2):256-274
This article is part of a larger project focusing upon explanatory illustrations that children encounter in pre- and primary school education. The research questions concerned (a) how preschool children make sense of iconic symbols when placing items of refuse on illustrations of refuse bins in a sorting task and (b) what stumbling blocks they encounter when interpreting these symbols. Video data were collected with 30 children between four and five?years of age. From the children’s verbal and non-verbal interactions, four different categories of sense-making were constructed: by material, by object type, by appearance and by function. Three stumbling blocks were identified. The first had to do with giving the symbols a different logical meaning to the intended one; the second related to what materials the different refuse items were made of; the third was being able to stick to one correct way of interpreting each symbol. 相似文献
15.
Objective： To test the effects of corrective spectacles in hyperopic amblyopic children with heterophoria. Methods： Visual acuity, refraction and the amount of heterophoria on near （33 cm） fixation were measured before and after 3 weeks of spectacle-wearing in 30 hyperopic amblyopic children with heterophoria. The control group consisted of 20 emmetropic children age-matched to the patients. Results： Uncorrected eyes displayed hyperopic amblyopia accompanied by heterophoria. Corrective spectacles not only attenuated the hyperopia and amblyopia, but also changed the heterophoria to orthophoria. The amount of heterophoria before wearing spectacles was significantly different from that in emmetropic children; but after correction with spectacles, it was the same as that in the emmetropic controls. Conclusion： Correction with spectacles is effective for the treatment of heterophoria in hyperopic children with amblyopia. 相似文献
16.
为了开发利用塔里木沙漠公路沿线的地上咸水,在塔克拉玛干沙漠北缘开展了不同灌溉周期试验.在流动风沙土和荒漠林土两种类型的土壤上,各设计5d、10d、15d、30d 4个灌溉周期,灌溉水均为28 g/L的地下水,灌水定额相同,均为1250 m3/hm2,研究在不同类型土壤上灌溉周期对土壤水盐变化的影响.结果表明:随着灌溉周期的增长,土壤水分明显减少;不同的灌溉周期,灌溉周期短的样地表层土壤电导率高于其它样地,但土体中层电导率低于其它样地,原因是较多的灌水把盐分向下层淋洗. 相似文献
17.
In two experiments, behavioral stereotypies elicited by scheduled presentations of food and water were compared. In Experiment 1, pigeons were exposed to a fixed-time 30-sec (FT 30-sec) schedule of food or water deliveries with a brightening keylight stimulus signaling time to the unconditioned stimulus (UCS) on each trial. Food and water presentations both produced terminal autoshaped keypecking that was similarly distributed in the trial but differed in response topography and persistence. Locomotor interim behavior was different in the two motivational conditions: With food presentations, it consisted of a “retreat” to the rear of the chamber after UCS termination, followed by “pacing” in the midportion of trials. The water schedule produced very little locomotor activity with no regular distribution in the trial. Experiment 2, using a random-time 30-sec (RT 30-sec) schedule, showed that the differences in interim locomotor behavior persisted in the absence of temporal predictability of the UCS and the keypecking terminal response. The results are taken to support Timberlake’s (1983a) behavior-system theory. 相似文献
18.
Heng Yuan Kyu-jin Kin Won-seok Kang Byoung-ho Kang Se-hyuk Yeom Jae-ho Kim Shin-won Kang 《浙江大学学报(A卷英文版)》2011,12(5):368-373
This paper presents a high-efficiency technique based on dielectrophoresis (DEP) for assembling metal, semiconductor, and
polymer nanorods, which are synthesized by electrochemical deposition (ECD). The assembly patterns of these nanorods (width:
20 nm; length: 7 μm) were designed using a finite element method (FEM) simulation tool. Further, these nanorods were used
in our experiment after their assembly patterns were fabricated. The assembly yield was found to be approximately 70% at an
AC voltage of 30 Vp-p and at frequencies of 20 and 30 kHz, and the DC voltage prevented the random alignment of the nanorods at the edge of the
assembly pattern. Moreover, the above-mentioned nanorods, which had different permittivities, were found to have similar assembly
yields. The proposed method can be improved and applied to nanostructure device fabrication. 相似文献
19.
AWAD Samir Hamid 《重庆大学学报(英文版)》2005,4(1)
1 Introduction Weight saving materials such as aluminum and its alloys are becoming increasingly important and have been attracting increasing attention over the past decade, specially in the automotive, aerospace and chemical industries, and electrical devices because of their high strength-to-weight ratio, high electrical and thermal conductivities, processability and recyclability and good resistance to degradation in some corrosive environments [1,2]. In the automotive industry, there is d… 相似文献
20.
100 g/L虫螨腈悬浮剂防治甘蓝小菜蛾田间药效试验 总被引：2，自引：0，他引：2
通过不同浓度的虫螨腈悬浮剂、50％丁醚脲悬浮剂和4．5％高效氯氰菊酯对甘蓝小菜蛾的药效试验,结果得出：在小菜蛾幼虫2～3龄前,使用100g／L虫螨腈悬浮剂30-50ml／667m^2效果最佳且无药害现象。 相似文献