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排序方式: 共有12条查询结果,搜索用时 15 毫秒
1.
从合肥永信建材有限公司粉磨现状出发,提出用FPP预粉磨改进球磨机粉磨矿渣工艺,剖析FPP预粉磨节能粉磨机理,比较改造前后能耗统计值,得到结论:FPP预粉磨改进了球磨机粉磨矿渣工艺,实现节能粉磨。  相似文献   
2.
ERP系统能够明显影响企业未来的竞争力和企业绩效。ERP系统的选择是一个典型的多因素决策问题。基于BOCR理论建立了ERP系统选择的评价指标体系,考虑了准则/指标之间的相互影响和反馈关系。由于评价过程中信息的不精确和模糊性,用三角模糊数表示专家或决策者的偏好意见,根据模糊优先规划方法计算三角模糊判断矩阵的局部权重。依据准则/指标之间的网络结构关系建立了未加权超矩阵,计算了收敛后的极限超矩阵,以得出各指标的综合权重。最后以案例说明如何应用提出的方法。  相似文献   
3.
目的基于试验测试结果,研究微粒子喷丸(FPP)技术对螺栓防松性能的影响及机理。方法使用微粒子喷丸工艺处理了两种硬度不同的螺栓(不锈钢螺栓和镀锌螺栓),使用螺栓横向振动试验装置在液压伺服万能疲劳试验机上对以上两种类型的未喷丸螺栓及喷丸螺栓进行了反复加载振动试验。试验结束后,使用扫描电镜(SEM)对螺纹配合处的螺栓螺牙进行了磨损形貌观察。结果未喷丸情况下,镀锌螺栓比不锈钢螺栓的防松能力低约40%。微粒子喷丸处理后,镀锌螺栓的防松能力提高了28%,而不锈钢螺栓的防松能力提高了15%,微粒子喷丸对镀锌螺栓的防松能力提高更加显著。螺纹表面的磨损程度越低,螺栓的防松能力越强。结论微粒子喷丸处理提高了螺牙表面的硬度,减轻了螺牙的磨损程度,从而改善了螺栓的防松性能。微粒子喷丸技术对螺栓防松能力的改善程度随着螺栓螺牙表面硬度的增加而增大。  相似文献   
4.
通过对交换机排队系统进行仿真,分析了以分形点过程( FPP )自相似业务流为输入的排队系统的性能.仿真结果显示,自相似业务流量模型下队列的性能与传统指数流量模型下的队列性能大不相同.文中所获得的仿真结果可用于网络流量模型、网络设计、网络拥塞控制和流量工程等.  相似文献   
5.
β-caryophyllene is a common sesquiterpene compound currently being studied as a promising precursor for the production of high-density fuels. Acute demand for high-density fuels has provided the impetus to pursue biosynthetic methods to produce β-caryophyllene from reproducible sources. In this study, we produced β-caryophyllene by assembling a biosynthetic pathway in an engineered Escherichia coli strain of which phosphoglucose isomerase gene has been deleted. The 1- deoxy-d-xylulose 5-phosphate (DXP) or heterologous mevalonate (MVA) pathways were employed. Meanwhile, geranyl diphosphate synthase, glucose-6-phosphate dehydrogenase and β-caryophyllene synthase genes were co-overexpressed in the above strain. The final genetically modified strain, YJM59, produced 220 ± 6 mg/L of β-caryophyllene in flask culture. We also evaluated the use of fed-batch fermentation for the production of β-caryophyllene. After induction for 60 h, the YJM59 strain produced β-caryophyllene at a concentration of 1520 mg/L. The volumetric production fermented in the aerobic fed-batch was 0.34 mg/(L·h·OD600) and the conversion efficiency of glucose to β-caryophyllene (gram to gram) was 1.69%. Our results are the first successful attempt to produce β-caryophyllene using E. coli BL21(DE3), and provide a new strategy that is green and sustainable for the production of β-caryophyllene.  相似文献   
6.
Lysophosphatidic acid (LPA) is the umbrella term for lipid signaling molecules that share structural homology and activate the family of LPA receptors. Farnesyl Pyrophosphate (FPP) is commonly known as an intermediate in the synthesis of steroid hormones; however, its function as a signaling lipid is beginning to be explored. FPP was recently shown to an activator of the G-protein coupled receptor 92 (also known as LPA5) of the calcium channel TRPV(3). The LPA receptors (including GPR92) are associated with the signal transduction of noxious stimuli, however, very little is known about the distribution of their signaling ligands (LPAs and FPP) in the brain. Here, using HPLC/MS/MS, we developed extraction and analytical methods for measuring levels of FPP and 4 species of LPA (palmitoyl, stearoyl, oleoyl and arachidonoyl-sn-glycerol-3 phosphate) in rodent brain. Relative distributions of each of the five compounds was significantly different across the brain suggesting divergent functionality for each as signaling molecules based on where and how much of each is being produced. Brainstem, midbrain, and thalamus contained the highest levels measured for each compound, though none in the same ratios while relatively small amounts were produced in cortex and cerebellum. These data provide a framework for investigations into functional relationships of these lipid ligands in specific brain areas, many of which are associated with the perception of pain.  相似文献   
7.
介绍了自主设计的某油电混合拖轮动力系统的配置情况及工作模式。结合油电混合动力系统的典型运行模式,对每种模式下可调桨和定距桨的适用情况进行了分析比较,并提出了不同运行模式下配置定距桨的油电混合动力系统的设计思路。  相似文献   
8.
Gear pitting is a typical surface defect, and its accurate three-dimensional (3D) detection is significant for the operation and maintenance of equipment. Therefore, this paper develops a 3D gear pitting detection method based on digital twin. Firstly, a geometric model of gear pitting is built to expand the samples which are helpful improving the detection accuracy. Secondly, based on the gear pitting model and Unity, a virtual fringe projection profilometry (FPP) system is established in the metaverse for generating the deformation fringe patterns and retrieving their phases. To improve the accuracy of pitting detection, a gear pitting detection network (GPD-Net) is proposed. It can not only extract local and global characteristics from different spaces and scales but also fuse these features via the proposed attention-based conditional random field modules. Thus GPD-Net can retrieve the high-precision wrapped phase by a single fringe pattern. Meanwhile, an FPP system is built in the physical world, and the reconstructed actual point cloud images are imported into the virtual FPP system for the precise measurement of gear pitting. The developed measurement system can be regarded as a meta-defect-detection system. The experimental results show the superiority of GPD-Net over the state-of-the-art phase retrieval algorithms and the effectiveness of the proposed three-dimensional gear pitting detection method. The proposed 3D detection method based on FPP is not limited by the fault type, and it can be effectively applied to the 3D measurement of various surface defects.  相似文献   
9.
一种可靠的FPGA动态配置方法及实现   总被引:1,自引:0,他引:1  
陈曦  沈佐峰 《通信技术》2012,45(3):105-107,110
现场可编程逻辑门阵列(FPGA)在通信系统中的应用越来越广泛。随着通信系统的复杂化和功能多样化,很多系统需要在不同时刻实现不同的功能,多数场合需要FPGA能够支持在线动态配置;在某些安全领域,需要对FPGA程序进行加密存储、动态升级。这里根据应用趋势提出了一种基于CPU+CPLD的可靠的FPGA动态加载方法。该方法具有灵活、安全、可靠的特点,在通信电子领域具有一定的参考价值。  相似文献   
10.
该文考虑小区间业务均匀分布,提出了频谱功率分割(Frequency Power Partition,FPP)机制:小区间频率复用因子为1,2/3的频谱为低功率频谱,剩余频谱为高功率频谱,且相邻小区的高功率频谱相互正交.结合FPP特点,从吞吐量和公平性角度出发,分别提出了基于影响度的频谱分配(Influence-based Frequency Allocation,IFA)算法和基于收益与影响度的频谱分配(Profitability-and-Influence based Frequency Allocation,PIFA)算法.最后考虑到小区内用户和业务分布的不均匀性,设计了一种简单的功率控制机制.仿真和分析结果表明与软频率复用(SFR)相比,FPP+IFA和FPP+PIFA分别使系统吞吐量和公平性得到较大改善,且功率控制机制进一步提高了用户和业务分布不均匀时的系统吞吐量.  相似文献   
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