scholarly journals Leaf Preference of Heliothrips hαemorrhoidαlis (Thysonoptera: Thripidae) on Vιburnum tinus

2017 ◽  
Vol 14 ◽  
pp. 41
Author(s):  
V. Α. Koufos ◽  
D. CH. Perdikis

The leaf preference of larvae, pupae and adults of Heliothrips haemorrhoidalis (Buche) (Thysanoptera: Thripidae), a serious pest of several ornamental plants, were studied on Viburnum tinus. Leaves were sampled for thrips from the base, middle and distal end of viburnum twigs at weekly intervals from April 11 to September 15, 2000. The population of this thrips was observed at high levels of between 10 to 76 thrips per leaf, till the middle of June when it sharply declined to zero, probably due to high temperatures. Higher populations developed on the basal than on the middle leaves. The lowest populations were recorded on the distal leaves. The predator Orius vicinus (Ribaut) (Hemiptera: Anthocoridae) was recorded in low numbers and therefore its effect on thrips populations was considered negligible.

Author(s):  
N. S. Rak ◽  
S. V. Litvinova

The results of long-term entomological observations at nurseries and in the collection greenhouse of PABSI are presented. The species composition of pests in the collections of open and closed ground of flower and ornamental plants in thePolar-AlpineBotanical gardenwas determined. The dominant invertebrates in nurseries are: Deroceras reticulatum Mtill., Eriophyes padi (Nal), Macrosiphum rosae L., Philaenus spumarius L., Gonioctena quinquepunctata F., Gonioctena pallida L., in greenhouses - Brevipalpus obovatus Donn., Neomyzus circumflexus Buckt., Myzodes persicae Sulz., Heliothrips haemorrhoidalis Bouche. Long-term observations of the state of flower and ornamental plants in greenhouses have shown that not only the species composition changes, but also the status of pests. An important role in the formation of the artificial biocenosis of the greenhouse is played by the food preferences of phytophages. Regular surveys revealed the presence of pests on plants of 41 families. The distribution of plants by the degree of pest population depending on the life form is presented. The most actively populated by the species of tree and shrub groups. The presented species composition of pests of flower and ornamental plants of open and closed ground can not be considered definitively studied, since changes in the trophic relationships of pests were noted during the study period.


Author(s):  
Z. L. Wang ◽  
J. Bentley

Studying the behavior of surfaces at high temperatures is of great importance for understanding the properties of ceramics and associated surface-gas reactions. Atomic processes occurring on bulk crystal surfaces at high temperatures can be recorded by reflection electron microscopy (REM) in a conventional transmission electron microscope (TEM) with relatively high resolution, because REM is especially sensitive to atomic-height steps.Improved REM image resolution with a FEG: Cleaved surfaces of a-alumina (012) exhibit atomic flatness with steps of height about 5 Å, determined by reference to a screw (or near screw) dislocation with a presumed Burgers vector of b = (1/3)<012> (see Fig. 1). Steps of heights less than about 0.8 Å can be clearly resolved only with a field emission gun (FEG) (Fig. 2). The small steps are formed by the surface oscillating between the closely packed O and Al stacking layers. The bands of dark contrast (Fig. 2b) are the result of beam radiation damage to surface areas initially terminated with O ions.


2003 ◽  
Vol 762 ◽  
Author(s):  
A. Gordijn ◽  
J.K. Rath ◽  
R.E.I. Schropp

AbstractDue to the high temperatures used for high deposition rate microcrystalline (μc-Si:H) and polycrystalline silicon, there is a need for compact and temperature-stable doped layers. In this study we report on films grown by the layer-by-layer method (LbL) using VHF PECVD. Growth of an amorphous silicon layer is alternated by a hydrogen plasma treatment. In LbL, the surface reactions are separated time-wise from the nucleation in the bulk. We observed that it is possible to incorporate dopant atoms in the layer, without disturbing the nucleation. Even at high substrate temperatures (up to 400°C) doped layers can be made microcrystalline. At these temperatures, in the continuous wave case, crystallinity is hindered, which is generally attributed to the out-diffusion of hydrogen from the surface and the presence of impurities (dopants).We observe that the parameter window for the treatment time for p-layers is smaller compared to n-layers. Moreover we observe that for high temperatures, the nucleation of p-layers is more adversely affected than for n-layers. Thin, doped layers have been structurally, optically and electrically characterized. The best n-layer made at 400°C, with a thickness of only 31 nm, had an activation energy of 0.056 eV and a dark conductivity of 2.7 S/cm, while the best p-layer made at 350°C, with a thickness of 29 nm, had an activation energy of 0.11 V and a dark conductivity of 0.1 S/cm. The suitability of these high temperature n-layers has been demonstrated in an n-i-p microcrystalline silicon solar cell with an unoptimized μc-Si:H i-layer deposited at 250°C and without buffer. The Voc of the cell is 0.48 V and the fill factor is 70 %.


2017 ◽  
Vol 8 (5) ◽  
pp. 221
Author(s):  
Sugiono Sugiono ◽  
Suluh E. Swara ◽  
Wisnu Wijanarko ◽  
Dwi H. Sulistyarini

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