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排序方式: 共有299条查询结果,搜索用时 343 毫秒
31.
D. V. Dev Usha Rani Batra R. N. Joshi 《Journal of the science of food and agriculture》1974,25(6):725-733
The effects of fertilisers, frequency of cutting, row spacing and simazine on the yields of dry matter and extractable protein from lucerne (Medicago sativa L.) were studied using the laboratory-scale pulper and press. Between 40 and 65% protein nitrogen was extractable; extractability was not affected by the various treatments but altered with season. Lucerne responded with increased yields of dry matter and extractable protein to fertilisers, simazine (35 g/ha) and rows spaced at 30.5 cm. Six or 8 harvests were found to give greater yields than 5 harvests in 180 days. The annual yields of extractable protein reached 3100 kg/ha and it is felt that better control of pests could lead to even greater yields. 相似文献
32.
The pressure-volume relation of ytterbium has been determined up to 9 Gpa using tungsten carbide opposed anvil high pressure
x-ray camera. The fcc phase of ytterbium is observed between one atmosphere and 4 GPa and the bcc phase above 3·5 GPa. The
bcc phase can be metastably retained down to 1 GPa by gradually decreasing the pressure from a region where only bcc phase
alone is observed. The bulk modulus,B
0, at zero pressure and the pressure derivative of the bulk modulus,B’
0, are determined by fitting Murnaghan equation to the pressure-volume data. The following values were obtained:B
0=16·3 GPa andB’
0=3·6 for the fcc phase, andB
0=14·7 GPa andB’
0=1·5 for the bcc phase. Based on the present data it is suggested that the thermodynamic equilibrium pressure for fcc ⇆ bcc
transformation in ytterbium is below 3·5 GPa. The valence change under pressure has been discussed. 相似文献
33.
34.
Significant structure theory (SST) of Eyring has been employed to calculate theoretically the viscosity of binary molten electrolytes on the basis of rigid sphere model. For KClNaCl and KClKBr systems the agreement between theoretical and experimental values is found to be satisfactory. 相似文献
35.
36.
The aim of the study was to evaluate the impact of environmental contaminants on oxidative stress biomarkers in hepatocytes of Indian estuarine water grey mullet, Mugil cephalus collected from unpolluted Kovalam and polluted Ennore estuaries. Initially, a comparison was made between the general water chemistry and environmental pollutants like heavy metals to identify the ecotype of the estuaries. Biomarker responses and bioaccumulation of metals were determined along with histological studies of fish hepatocytes to assess contamination impact. Water chemistry data with higher temperature, salinity, pH, biochemical oxygen demand, chemical oxygen demand and low dissolved oxygen and environmental pollutants with higher metal concentration (p < 0.05) were observed at Ennore than Kovalam indicating its polluted environment. A significant increase (p < 0.05) in lipid and protein oxidation markers, decrease (p < 0.05) in thiol status and antioxidant enzyme activities were observed in the Ennore fish hepatocytes compared to Kovalam counterpart. Bioaccumulation of heavy metals was significantly higher (p < 0.05) in fish from Ennore. Hepatocytes from Ennore also featured extensive lipid-type vacuolation, increased size and membrane disruption. All the findings highlighted the value of oxidative stress biomarkers and membrane disruption as the sensitive parameters of environmental pollutant contamination and their importance in biomonitoring of aquatic ecosystems. This is also the first such attempt reported at the cellular level from South India stressing the importance of biomarkers in biomonitoring programmes using fish hepatocytes as the model system. 相似文献
37.
Wireless Personal Communications - A VANET is an excellent instance of a wireless sensor network. The mobile vehicles are the nodes and communication happens between the vehicular nodes. This... 相似文献
38.
In this paper, we investigated synchronisation problem for stochastic Takagi–Sugeno (T-S) fuzzy complex networks model with discrete and distributed time delays. By constructing a new Lyapunov functional and employing Kronecker product, we developed delay-dependent synchronisation criterions. By applying stochastic analysis techniques, we derive starting conditions for synchronisation complex networks of the addressed with mixed time-varying delays and stochastic disturbances are achieved. A numerical examples are provided to demonstrate the effectiveness and usefulness of the proposed results. 相似文献
39.
Clustering is one of the essential operations in wireless sensor network (WSN) to ensure organized data aggregation followed by energy efficiency. However, obtaining optimal clustering performance is yet an unsolved problem in WSN. Review of existing approaches towards cluster optimization shows that effective balance between energy efficiency and topology control is still missing. Therefore, the proposed system presents a unique topology control mechanism using a novel concept of interstellar orientation toward optimizing the clustering performance in WSN. Adopting an analytical research methodology, the proposed system introduces two interstellar‐based topology control system, which targets the maximum saving of resource consumption of the cluster head. The simulated outcome of the study shows that the proposed topology control system offers significant energy conservation performance in comparison to the existing hierarchical clustering scheme in WSN. 相似文献
40.
André Scholz Argang Ghadiri Usha Singh Johannes Wendsche Theo Peters Stefan Schneider 《Ergonomics》2018,61(2):255-264
Work breaks are known to have positive effects on employees’ health, performance and safety. Using a sample of twelve employees working in a stressful and cognitively demanding working environment, this experimental field study examined how different types of work breaks (boxing, deep relaxation and usual breaks) affect participants’ mood, cognitive performance and neurophysiological state compared to a control condition without any break. In a repeated measures experimental design, cognitive performance was assessed using an auditory oddball test and a Movement Detection Test. Brain cortical activity was recorded using electroencephalography. Individual’s mood was analysed using a profile of mood state. Although neurophysiological data showed improved relaxation of cortical state after boxing (vs. ‘no break’ and ‘deep relaxation’), neither performance nor mood assessment showed similar results. It remains questionable whether there is a universal work break type that has beneficial effects for all individuals.
Practitioner Summary: Research on work breaks and their positive effects on employees’ health and performance often disregards break activities. This experimental field study in a stressful working environment investigated the effect of different work break activities. A universal work break type that is beneficial for this workplace could not be identified. 相似文献