首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   7篇
  免费   0篇
化学工业   2篇
轻工业   1篇
无线电   2篇
一般工业技术   1篇
自动化技术   1篇
  2022年   1篇
  2021年   1篇
  2020年   1篇
  2010年   1篇
  2008年   1篇
  1995年   1篇
  1989年   1篇
排序方式: 共有7条查询结果,搜索用时 15 毫秒
1
1.
Defect tolerant fatigue design for automotive components fabricated from HSLA steel is considered to understand how to overcome the overestimated design based on conventional S/N approach. The stress concentration arising from material inhomogeneities, micro discontinuities and geometric discontinuities are considered. Notch sensitivity and formation of non-propagation cracks are related to crack closure. The overall crack closure effect under tension loading facilitated the development of non-propagating cracks and have increased the endurance limit by approximately 8%.  相似文献   
2.

One of the main disadvantages of multicarrier transmission is the high peak-to-average power ratio (PAPR) of the transmitted signal. If the highest transmitted power is confined by the application restrictions or regulatory, the result is to decrease the average power permitted under multicarrier transmission. Selected mapping (SLM) is a standard PAPR reduction scheme that is appropriate for orthogonal frequency division multiplexing (OFDM) scheme as it realizes the performance of PAPR reduction without signal distortion. This paper proposes a method in order to handle the difficulties of high PAPR in OFDM scheme. The offered system is an arrangement of two distinguished methods, such as clipping and SLM. Compared to other hybrid methods, where the individual methods are implemented sequentially, this paper integrates the clipping method in the SLM procedure. This produces a supplementary PAPR reduction associated to the serial arrangement. Simulation results specify that the offered scheme acquires the performance of appropriate PAPR reduction with low computational complexity. The PAPR reduction at different number of subcarriers is analyzed and compared with the existing research work. The performance of relative energy efficiency has also been focused on this paper.

  相似文献   
3.
Fermented milk product (Indian curd) was developed by using peanut milk. The level of incubation period (IP), skimmed milk powder (SMP), carboxymethyl cellulose (CMC) was optimised using response surface methodology (RSM). Central composite rotatable design was used with three independent variables i.e. IP (16–20 h), SMP (3–5%) and CMC (0.1–0.3%). SMP had significant (P 0.05) positive effect on overall acceptability (OAA) of curd because of increase in the total solids that ultimately increased firmness of the curd. CMC was found effective in reducing the synersis of curd samples. The developed curd samples had moisture 84.8 ± 0.28%, protein 3.2 ± 0.12%, fat 3.5 ± 0.10%, ash 0.5 ± 0.05%, carbohydrate 8.0% (wb), peak viscosity 291.4 ± 3.52 cP, firmness 1.3 ± 0.15 N, synersis 32.1 ± 0.2 mL 100 g?1 and acidity (as % lactic acid) 0.58 ± 0.02. It had OAA score of 7.8 ± 0.2 on nine‐point hedonic scale. Based on compromise optimisation, the conditions recommended were IP as 18 h, SMP, 4.24% and CMC, 0.19% for making peanut milk–based fermented curd with 83.4% desirability.  相似文献   
4.
Sodium salts of N,N-dibenzyldithiocarbamate, N,N-diisopropyldithiocarbamate and pyrrolidine-1-carbodithioate gave cyclic products, 4-oxo-2,6-diphenyl-piperidinium, 2,2,6,6-tetramethyl-4-oxo-piperidinium and 3-oxo-8-azonia-bicyclo[3.2.1]octane cations, respectively, when treated with aluminum trichloride in acetone. The 2,2,6,6-tetramethyl-4-oxo-piperidinium thiocyanate salt has been characterized by X-ray crystallography. A plausible mechanism has also been suggested on the basis of preliminary DFT calculations.  相似文献   
5.
The oxidative coupling of methane to ethylene and ethane was studied over lithium–cerium-promoted MgO and MgO–CaO catalysts in the presence of molecular oxygen at 730°C and at atmospheric pressure in a continuous flow, fixed bed quartz reactor. The catalysts were prepared by an impregnation method and finally calcined at 900°C. The surface area, pore size distribution and pore volume of the catalysts were determined. The feed consisted of only methane and oxygen in the molar ratio of 2:1. The results obtained over the catalyst systems, viz. (i) lithium–cerium-promoted MgO and (ii) lithium–cerium-promoted MgO–CaO, have been compared. A relatively high C2-selectivity has been obtained with Li–Ce-promoted MgO–CaO catalysts. The optimum yield and selectivity for C2-hydrocarbons were found to be 21·5% and 76·8% respectively at a methane conversion of 28% over Li (7 wt%)–Ce (2 wt%)-doped MgO–CaO (3:1 wt ratio) catalyst. The various factors governing the activity and the selectivity of the catalyst systems have been discussed.  相似文献   
6.

Dementia is one of the leading causes of severe cognitive decline, it induces memory loss and impairs the daily life of millions of people worldwide. In this work, we consider the classification of dementia using magnetic resonance (MR) imaging and clinical data with machine learning models. We adapt univariate feature selection in the MR data pre-processing step as a filter-based feature selection. Bagged decision trees are also implemented to estimate the important features for achieving good classification accuracy. Several ensemble learning-based machine learning approaches, namely gradient boosting (GB), extreme gradient boost (XGB), voting-based, and random forest (RF) classifiers, are considered for the diagnosis of dementia. Moreover, we propose voting-based classifiers that train on an ensemble of numerous basic machine learning models, such as the extra trees classifier, RF, GB, and XGB. The implementation of a voting-based approach is one of the important contributions, and the performance of different classifiers are evaluated in terms of precision, accuracy, recall, and F1 score. Moreover, the receiver operating characteristic curve (ROC) and area under the ROC curve (AUC) are used as metrics for comparing these classifiers. Experimental results show that the voting-based classifiers often perform better compared to the RF, GB, and XGB in terms of precision, recall, and accuracy, thereby indicating the promise of differentiating dementia from imaging and clinical data.

  相似文献   
7.

Breast cancer is a common cancer in women. Early detection of breast cancer in particular and cancer, in general, can considerably increase the survival rate of women, and it can be much more effective. This paper mainly focuses on the transfer learning process to detect breast cancer. Modified VGG (MVGG) is proposed and implemented on datasets of 2D and 3D images of mammograms. Experimental results showed that the proposed hybrid transfer learning model (a fusion of MVGG and ImageNet) provides an accuracy of 94.3%. On the other hand, only the proposed MVGG architecture provides an accuracy of 89.8%. So, it is precisely stated that the proposed hybrid pre-trained network outperforms other compared Convolutional Neural Networks. The proposed architecture can be considered as an effective tool for radiologists to decrease the false negative and false positive rates. Therefore, the efficiency of mammography analysis will be improved.

  相似文献   
1
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号