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排序方式: 共有4042条查询结果,搜索用时 15 毫秒
41.
周静 《数码设计:surface》2012,(5):144-146
我国在商、周之交,就开始了早期的中西交流,而张骞西行后又开辟了新的中外来往的交通路线。我国的玻璃业尽管没能发展为重要的手工业门类,但它始终在持续而缓慢的发展,更重要的是,正是由于玻璃业的非主流,在发展过程中凸显了外部因素的重要性。丝绸之路在中国古代玻璃艺术的发展过程中起到了重要作用。 相似文献
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Nasir A. Al-geelani M. Afendi M. PiahRedhwan Q. Shaddad 《Applied Soft Computing》2012,12(4):1239-1246
A hybrid model incorporating wavelet and radial basis function neural network is presented which is used to detect, identify and characterize the acoustic signals due to surface discharge activity and hence differentiate abnormal operating conditions from the normal ones. The tests were carried out on cleaned and polluted high voltage glass insulators by using surface tracking and erosion test procedure of international electrotechnical commission 60587. A laboratory experiment was conducted by preparing the prototypes of the discharges. This study suggests a feature extraction and classification algorithm for surface discharge classification, which when combined together reduced the dimensionality of the feature space to a manageable dimension, by “marrying” the wavelet to radial basis function neural network very high levels of classification are achieved. Wavelet signal treatment toolbox is used to recover the surface discharge acoustic signals by eliminating the noisy portion and to reduce the dimension of the feature input vector. A radial basis function neural network classifier was used to classify the surface discharge and assess the suitability of this feature vector in classification. This learning method is proved to be effective by applying the wavelet radial basis function neural network in the classification of surface discharge fault data set. The test results show that the proposed approach is efficient and reliable. 相似文献
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The effects of suspended fibre on macroscale and microscale mixing in a small stirred tank reactor were studied under batch conditions using the competitive, consecutive azo coupling between 1-naphthol and diazotized sulfanilic acid. The mixing quality was determined from the distribution between the mono and bis substituted reaction products. Nylon (2 and 3 millimeters in length) and fully bleached softwood kraft pulp (FBK) fibre suspensions were examined at volumetric concentrations up to the limit that complete suspension motion could be maintained in the vessel at impellet rotational speeds of 7 and 10s-1. The adsorption of the product dyes on the fibre was found to be proportional or very nearly proportional to their concentrations in the aqueous phase and did not interfere with the assessment of mixing in the suspension.
Suspended fibres were found to slightly increase the 'critical feed time' of the diazotized sulfanilic acid, corresponding to an increase in the macromixing or bulk blend lime of the vessel. Continued increase in the fibre concentration led to the formation of a well mixed cavern centered on the impeller and the creation of stagnant regions adjacent to the vessel walls. The departure from the Newtonian fibre-free case is due to changes in the flow through and distribution of the energy dissipative regions in the vessel. The most effective location for chemical addition to ensure good microscale mixing remains in the impeller vicinity. 相似文献
Suspended fibres were found to slightly increase the 'critical feed time' of the diazotized sulfanilic acid, corresponding to an increase in the macromixing or bulk blend lime of the vessel. Continued increase in the fibre concentration led to the formation of a well mixed cavern centered on the impeller and the creation of stagnant regions adjacent to the vessel walls. The departure from the Newtonian fibre-free case is due to changes in the flow through and distribution of the energy dissipative regions in the vessel. The most effective location for chemical addition to ensure good microscale mixing remains in the impeller vicinity. 相似文献
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我厂总结加料实际运行情况,分析加料口对配合料熔化作业的影响,在仍采用一台(嘴宽为800mm)毯式推料加料机情况下,对24m~2的马蹄焰熔炉加料口结构进行了改进,取得了较好的效果。 相似文献
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熔制玻璃用坩埚抗热震性的改进 总被引:1,自引:0,他引:1
在粘土 -蜡石质玻璃用坩埚的配方基础上 ,研究了蜡石的粒径和加入量的变化对试样抗热震性的影响。结果发现 :减小蜡石的粒径与加入量均可提高试样的抗热震性 ,但减小蜡石粒径对提高试样的抗热震性更有效 ;在配料中引入少量的蓝晶石细粉 ,可明显提高试样的抗热震性。 相似文献
49.
P ThomasD Billaud 《Electrochimica acta》2002,47(20):3303-3307
The electrochemical insertion of sodium ions into different types of hard carbons was achieved in electrolytes composed of ethylene carbonate as the solvent and NaClO4 as the salt. For all the materials studied the sodium uptake increases when the carbon highest heat treatment temperature (HTT) decreases. PAN-based carbon fibres appear to be suitable structures to allow significant sodium insertion. Thus, T650 ex-PAN fibres lead to a reversible capacity close to 209 mAh g−1. In that case, sodium insertion occurs in two main ways: one is the adsorption on the single graphene layers and the other is the concomitant insertion into the porosity that occurs below 0.1 V versus Na+/Na. This second mechanism, which is indicated by a low-voltage plateau on the electrochemical curves, allows significant insertion. The compared electrochemical study of two saccharose-coke samples corresponding to different regions of Dahn's classification underlines the importance of the carbon precursor and of the manufacture process. The reversible capacity is equal to 184 mAh g−1 for the sample heat treated at 800 °C which presents a high hydrogen content whereas it is close to 145 mAh g−1 for the one characterized by a HTT of about 1500 °C and a low hydrogen content. The best electrochemical performances are obtained for pyrolyzed cellulose carbons. Indeed, the reversible capacity is about 279 mAh g−1. Outgassing these carbons at 950 °C results in such a decrease of the reversible capacity down to 145 mAh g−1. That can be related either to the thermal elimination of heteroelements or to modifications of the pore size distribution. Consequently, the most suitable hard carbon material for anodic applications in rechargeable sodium-ion batteries should both present a high residual hydrogen content and a significant microporosity. 相似文献
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