黄土耕作坡面溅蚀过程中微地形响应特征

[目的]探究60mm/h雨强下不同耕作坡面在溅蚀阶段的微地形变化特征,为黄土坡地水土保持耕作方式布设提供科学依据。[方法]在室内人工模拟降雨试验的基础上,采用激光扫描量测方法分别获取溅蚀前后4种不同耕作方式(人工锄耕、人工掏挖、等高耕作、耙磨整平)黄土坡面微地形相对高程,并对能反映微地形变化的高精度M-ΔDEM进行了分析。[结果]不同耕作措施下坡面微地形均具有较弱的空间变异,其空间分异主要受耕作措施的影响;降雨对微地形具有一定的夷平效应,且不同耕作坡面在1~1.3m尺度范围内均表现出侵蚀平衡现象;不同耕作微地形对溅蚀均具有阻滞作用,其中人工掏挖和等高耕作具有较强的水土保持作用。[结论]微地形水系分维能较好地反映复杂的微地形特征,而坡面耕作方式是溅蚀过程中微地形时空变异分布状况的控制性因子。     

大型灯泡贯流式泵站振动研究概述

机组和泵房的振动是泵站运行中最为常见的问题,直接影响泵站的安全可靠运行。对大型灯泡贯流式泵站振动研究现状和抗振安全评价计算分析方法作了详细的介绍,对研究机组振动诱发泵房振动的共振校核法、拟静力法、谐响应求解法和瞬态动力时程法等进行了阐述,并对这几种方法进行了分析比较,就其存在的问题作了总结概述。     

工厂化水产养殖水质监测系统

工厂化水产养殖的密度高、风险大,养殖对象对pH、溶解氧、温度、氨氮、亚硝酸盐等水质参数的变化敏感,受影响严重,监测水质参数极为重要。本文针对工厂化水产养殖水质监测特点和需求,研发了工厂化水产养殖水质监测系统。分析研究pH、溶解氧、温度、亚硝酸盐等水质参数的阈值,设计水质监测数据无线采集节点和基于Zigbee的无线监测网络,建立水质监测系统软件平台。结果表明,该系统能够实现工厂化水产养殖水质实时监测,保证生产安全,提高水产养殖生产效率。     

Biological studies on the olive leaf moth, Palpita unionalis Hübner (Lepid., Pyralidae), and the olive moth, Prays oleae Bernard (Lepid., Yponomeutidae)

Abstract The biology of two important lepidopterous pests, Prays oleae Bernard and Palpita unionalis Hübner, was studied. The target pests were reared on olive plants, Oleae europaea L. (Oleaceae) under laboratory conditions for two successive generations, from March to June 2002. For P. oleae, the duration of larval stage development in the first generation was 21.4 ± 0.18 days at 19.3–20.9 °C, 65–68 % R.H, while in the second generation it was 14.8 ± 0.10 days at 20.8–24.2 °C, 65–69 % R.H. The number of eggs laid per female ranged from 58 to 109 eggs in the first generation, and from 47 to 113 in the second. The larval stage duration of P. unionalis was 16.3 ± 0.12 days at 16.8–22.9 °C, 65–69 % R.H. and 15.5 ± 0.12 days at 21.6–25.5 °C, 66–69 % R.H. for the first and second generations, respectively. Also, the number of eggs laid per female ranged from 630 to 653 eggs, and from 425 to 493 eggs in the second generation under the same previous laboratory conditions. P. oleae laid eggs at night mostly singly on flower-buds, more on the calyx. than on the petals. The larvae mined on leaves and damaged groups of flowers. P. unionalis adults were active at night, laid eggs singly at twilight usually on the lower surface of foliage. Larvae fed on leaves spinning several leaves together to form shelter for the pupa.     

几种甘蓝型油菜幼苗抗旱性特征的比较研究

以EV1、EV2、EV3、EV4、EV5、EV66个抗旱性不同的油菜品种为试验材料,通过不同浓度PEG-6000渗透溶液模拟干旱胁迫处理,研究油菜幼苗的抗旱指数、根长、苗高和根冠比等性状变化,探索在大田环境条件下的苗期生长特征。结果表明,水分胁迫下EV2的抗旱指数最大,EV6的抗旱指数最小;不同浓度PEG胁迫下,各品种差异显著, EV1、EV2、和EV3的根长、苗高和根冠比较大,而EV5和EV6的表现较差。在大田油菜五叶期时,EV2的冠层覆盖面积最大,与其它品种之间存在极显著性差异;总生物量以EV2、EV3和EV1较大,根系干重以EV2较大,而且三者之间存在显著相关性;与抗旱指数进行通径分析,冠层覆盖面积对抗旱性的直接通径系数最大,达到0.5975。冠层覆盖面积的大小反映了早期活力的强弱,早期活力强,相应的品种抗旱指数高,抗旱性强。     

Agglomeration and Competition among Chinese Cities: An Investigation of Taiwanese High‐Tech Foreign Direct Investment

The purpose of this study was to investigate how Taiwanese high‐tech firms' foreign direct investment (FDI) leads to agglomeration and competition among cities in China. By using social network analysis to analyze 1,111 subsidiaries affiliated with 270 multinational corporations (MNCs) during the years between 1988 and 2006 in 30 major Chinese cities, this study finds that: 1) agglomeration in Chinese cities falls into three primary categories: the hub cluster, the communication‐extended cluster, and the computer‐extended cluster. Among the aforementioned clusters, the hub cluster is the most critical in terms of firm location, and therefore is often a high‐priority investment site for Taiwanese high‐tech firms. 2) Chinese cities fall into four primary groups, or “blocks”: the core block, the coast block, the inland block, and the periphery block; these groups were determined by applying a structural equivalence analysis of which members of each type are in competition with one another. By linking the findings of the urban network characteristics to Chinese regional economic policies, this study provides guidance to aid executives in determining the optimal location for future FDI. Implications and suggestions for host country governments in terms of firms' investment strategies are also discussed.     

Effect of salinity and water table on the mineral content of plum and peach

The effects of combinations of salinity and water table on the mineral content of plum and peach were studied in lysimeters.Chloride content (Cl) in the leaves and the roots of plum and in the leaves of peach increased with salinity, whereas Cl in peach roots was not affected. Leaves of peach contained higher amounts of Cl than the leaves of plum. The opposite trend was observed in the roots.Sodium content (Na) increased with salinity in plum, whereas in peach it was not affected.The effect of salinity on calcium content (Ca) was not consistent in plum and peach.Potassium content (K) in the leaves of plum and peach decreased with salinity, whereas in the roots it was not affected.The Ca/K ratio in plum leaves increased with salinity, whereas in peaches it decreased in the 4000 p.p.m. treatment.Leaf phosphorus content (P) in the plum and the ‘Balady’ peach decreased with salinity, while in ‘Mit Ghamre’ peach it was not consistently affected. In plum root, P increased with salinity, whereas the effect was the opposite in peach.Magnesium content (Mg) was not significantly affected.The depth of the water table had no consistent effect on the Cl, Na, Ca, K, Ca/K ratio, P and Mg contents in the leaves and roots of plum or peach.The interaction between salinity treatments and water table levels was not significant in most cases.     

Towards sustainable control of Lepidopterous pests in olive cultivation

Zusammenfassung Traditionelle, extensiv bearbeitete Olivenhaine, aber auch moderne Intensiv-Plantagen mit künstlicher Bewässerung und hohem Einsatz von Düngern bzw. chemischen Pflanzenschutzmitteln kennzeichnen die derzeitigen verschiedenen Anbauformen der Olive im Mittelmeerraum. Schadlepidopteren wie die Olivenmotte (Prays oleae, Lep.: Yponomeutidae) und die Jasminmotte (Palpita unionalis, Lep.: Pyralidae) werden durch regelmässigen Insektizideinsatz bekämpft. Das von der EU geförderte internationale Forschungsprojekt TRIPHELIO zielte auf die Entwicklung insektizidfreier Alternativmethoden durch (1) die Optimierung der pheromongestützten Überwachung und Verwirrtechnik, (2) der Anwendung von Habitatmanagement-Strategien zur Förderung natürlicher Gegenspieler, und (3) dem Einsatz von Trichogramma-Schlupfwespen. Zusätzlich wurden Module für eine optimale Anwendung biotechnischer und biologischer Methoden bezüglich der Phänologie der Schadinsekten und möglicher Nebenwirkungen von Pestiziden erarbeitet. Die intensive Kooperation zwischen Wissenschaftlern und Praktikern aus mehreren Ländern Europas und Nordafrikas erlaubte den Entwurf möglicher Lösungsansätze für verschiedene Anbaubedingungen und klimatische Regionen des Mittelmeerraumes. Die wichtigsten Ergebnisse und Ausblicke für eine zukünftige praktische Umsetzung werden in dieser Veröffentlichung beschrieben.     

Investigation of salinity impacts on germination and growth of two forest tree species at seedling stage

Soil salinity is becoming an increasingly serious constraint to plant growth in many parts of the world;this is particularly common in semi-arid and arid zones. This study was conducted to evaluate the...