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21.
机电设备安装运行的异常现象及对策 总被引:1,自引:0,他引:1
目前,由于国产设备的技术水平和加工水平,与国外的技术设备有较大的差距,关键设备大多引进国外技术设备,其整体及配件价格十分昂贵.为了提高企业经济效益,这就要求机电设备维护人员对设备的一些异常现象,做到分析原因提出解决对策,降低设备故障减少设备维修费用. 相似文献
22.
Dianne Baunbk Nolwenn Trinkler Yoan Ferandin Olivier Lozach Poonsakdi Ploypradith Somsak Rucirawat Fumito Ishibashi Masatomo Iwao Laurent Meijer 《Marine drugs》2008,6(4):514-527
Lamellarins, a family of hexacyclic pyrrole alkaloids originally isolated from marine invertebrates, display promising anti-tumor activity. They induce apoptotic cell death through multi-target mechanisms, including inhibition of topoisomerase I, interaction with DNA and direct effects on mitochondria. We here report that lamellarins inhibit several protein kinases relevant to cancer such as cyclin-dependent kinases, dual-specificity tyrosine phosphorylation activated kinase 1A, casein kinase 1, glycogen synthase kinase-3 and PIM-1. A good correlation is observed between the effects of lamellarins on protein kinases and their action on cell death, suggesting that inhibition of specific kinases may contribute to the cytotoxicity of lamellarins. Structure/activity relationship suggests several paths for the optimization of lamellarins as kinase inhibitors. 相似文献
23.
Eelco van Beek Babak Bozorgy Zoltán Vekerdy Karen Meijer 《Irrigation and Drainage Systems》2008,22(2):131-143
The Sistan Delta in Iran is located at the end of a closed basin with nearly 100% of the supply coming from Afghanistan. This
supply is supporting irrigated agriculture in the area and is the source for the lake system around the delta. These Hamoun
lakes are ecological very valuable wetlands; a number of them are registered as Ramsar sites. The Iranian government tries
to improve the living conditions of the people in the area, among others by providing infrastructure for irrigated agriculture.
Further development of the irrigated area will mean less water for the Hamouns with resulting lower average water coverage
of the lakes. This will not only endanger the ecosystem that the Hamouns support but also the livelihoods of the people that
depend on the goods and services that the lakes provide. This paper describes a study that has been carried out to support
decision making on potential development schemes in the delta. The non-availability of data from Afghanistan requires the
development of various tools and the use of remote sensing techniques to enable to make estimates for the river flow that
Iran can expect from Afghanistan. An IWRM approach has been used for the balancing of interests involved. Some preliminary
conclusions are described. 相似文献
24.
Andrzej Bobiec Haico van der Burgt Kim Meijer Casper Zuyderduyn Jos Haga Bastiaan Vlaanderen 《Forest Ecology and Management》2000,130(1-3)
The Bia
owie
a Primeval Forest, Poland, is the only forest area in temperate Europe where large tracts of natural forest communities have been conserved. The concept of silvatic mosaic [Oldeman, R.A.A., 1990. Forests: Elements of Silvology. Springer, Berlin] was applied in order to characterise the structure of stands representing oak–lime–hornbeam forest in both, the restricted area of Bia
owie
a National Park (BNP) and the commercial forests (CF), as well as to indicate a holistic approach towards protection and restoration of natural areas.Six developmental phases of stands were distinguished and defined: regeneration, young, pole, late pole, optimal, and terminal. Compositional and structural differences between the first five phases were also evaluated and visualised. Moreover, the considerable differences between analogous phases in BNP and CF were found. The uniform stand patches were mapped into two plots in BNP (25 ha each) and two in CF (25 and 20 ha), with a resolution of 10 m× 10 m pixels.The mosaic composition of natural communities indicates close-to-the equilibrium stage: the biostatic optimal phase occupies 33–40% of the area, while aggradational younger phases share nearly the same portion of the area as the senescent phase does. Although small, 0.01–0.04 ha eco-units dominate in BNP, there is a considerable portion of intermediate and large patches, indicating a complex character of factors responsible for the mosaic structure of natural stands in BNP. Both, composition and texture analyses indicate that the area of 25 ha is close to the minimum structure area specific for the communities studied.The comparison of natural and managed stands revealed large deficits of the optimal phase (only 19%) and a total absence of the terminal one in the managed area (20–35% in natural forest). Also the mosaic texture of CF plots was simplified because of standardisation of the management unit size. The modification of developmental phases, mosaic composition, and structure must lead to changes in the dynamics of the entire community. The present study demonstrates that the natural forest should be considered as a dynamic supersystem, covering a sufficient area to allow the developmental phases to perform in correct proportions. Because of differences in the durability of various phases, the natural cycle of forest development has an asynchronous and highly unpredictable character. Indeed, the applicability of multipurpose forestry rules as a tool of nature conservation has been questioned. An absolute ban on cutting in the remaining old-growth stands should be a basic rule for the restoration management. 相似文献
25.
26.
R van den Hoven A E Meijer T Wensing H J Breukink 《American journal of veterinary research》1985,46(8):1755-1761
Gluteal muscle specimens were taken from 4 horses. From 1 of the 4 gluteal muscles, serial sections were prepared. Individual muscle fibers were identified and studied, using photomicrographs of sections stained by different enzyme histochemical methods. In specimens in which cytoplasmic soluble enzymes were studied, use was made of the semi-permeable membrane technique to hamper enzyme diffusion into reaction fluids. Enzymes involved in glycogenolysis, glycolysis, the tricarboxylic acid cycle, synthesis of reduced nicotinamide adenine dinucleotide phosphate, the pentose phosphate cycle, the alpha-glycerolphosphate shuttle, the respiratory chain, catabolism, and muscular contraction were studied. Some key enzymes of different metabolic pathways were also included. Each of 3 fiber types identified had distinct features. Type I fibers were characterized by a relatively strong aerobic capacity, compared with type IIA fibers, which were more glycolytic and had strong aerobic and moderate-to-strong anaerobic capacity. Type IIB fibers were characterized by a relatively low aerobic and a relatively high anaerobic capacity, and were glycolytic. Activities of phosphofructokinase, glyceraldehyde-3-phosphate dehydrogenase, lactate dehydrogenase, and alpha-naphtylesterase (nonspecific esterase) were so markedly different in the 3 fiber types that fiber typing was possible, aided by the demonstration of the activities of these enzymes. In type IIB fibers, the pentose phosphate cycle was more important than in the other fiber types. Except for the unexplained high alpha-naphtylesterase activity in type IIB fibers, catabolic enzymes were not active in healthy equine muscle fibers. 相似文献
27.
Long‐term Effects of Pyrethrin and Cyfluthrin,a Type II Synthetic Pyrethroid,Insecticide Applications on Bull Reproductive Parameters
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JL Stewart CF Shipley FA Ireland VL Jarrell CL Timlin DW Shike TL Felix 《Reproduction in domestic animals》2016,51(5):680-687
The objectives of this study were to determine effects of cyfluthrin and pyrethrin spray products, used in combination with cyfluthrin topical and ear tag applications, on bull reproductive parameters over 18 weeks. Angus or Angus x Simmental bulls were randomly assigned to one of three treatment groups: (i) no exposure to pyrethrins/cyfluthrin (CONT; n = 10), (ii) cyfluthrin ear tag and topical applications (ET; n = 10), or (iii) cyfluthrin ear tag, topical, premise spray and pyrethrin fog spray applications (ET+S; n = 8). Bull body weight was measured every 3 week, and body condition score and scrotal circumference were recorded on weeks 0, 9 and 18. Semen and serum were collected every 3 weeks for sperm evaluation and testosterone measurement, respectively. There was a treatment × week interaction (p < 0.01) for sperm with primary defects; bulls in CONT group had a greater (p = 0.01) percentage of sperm with primary defects than bulls treated with insecticides at week 18. Overall and progressive sperm motility, normal sperm morphology, secondary sperm defects and serum testosterone concentrations changed (p < 0.01) over time in all bulls; however, treatment did not affect (p ≥ 0.13) any of these parameters. There were also no treatment effects (p ≥ 0.08) on bull body weight, body condition score or scrotal circumference. The use of pyrethrin‐ and cyfluthrin‐based insecticides, regardless of application, did not negatively affect reproductive parameters in beef bulls when administered over 18 weeks. 相似文献
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30.
毛竹枯梢病的发生与气候和竹林的经营管理水平密切相关。通过实施清除病原,隔断侵染源、钩梢、垦复、施肥、烟剂防治等综合防治技术,使病害发生面积下降了90%,消灭了重度和中度危害区。发病率和感病指数分别下降了94%和85%。 相似文献