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81.
工期、成本、质量通常作为传统项目管理过程中三大目标,而工业互联网环境下预防性维修管理除了以上三大目标之外还更多的考虑了安全因素.根据设备机群内不同设备分析了其四大目标不同构成和内涵,四大目标决策权重采用经改进的带置信度的专家确定方法,根据工期约束等因素导出资源使用均衡条件.在此基础上构建了非线性条件下四方关系多属性效用函数模型.采用线性递减收敛因子改进下的多点交叉遗传算法进行优化求解,促使种群快速寻找最优解,算法表现出较好的收敛性和多样性使得寻优过程更加合理.  相似文献   
82.
The marginal cost approach for the analysis of repair/replacementmodels was introduced by Berg in 1980 and has since been appliedto many maintenance policies of various complexity. All modelshitherto analysed in the literature by the marginal cost approachhave one single decision variable only, this being, typically,the age of the current item at the time of ordering or replacement.This paper is concerned with the extension of the marginal costtechnique to maintenance policies with several decision variables.After addressing the general framework appropriate for the multi-parametercase, we exemplify the workings of the technique by analysinga two-variable maintenance model involving replacement and minimalrepair. We demonstrate that the marginal cost approach is anattractive and intuitively appealing technique also for modelswith several decision variables. Just as in the single-parametersituation, the approach is amenable to economic interpretation,a welcome feature for users of maintenance models with a primeinterest in its economic (rather than its mathematical) aspects.As an added bonus of the marginal cost approach, in our example,some otherwise necessary tools from the theory of stochasticprocesses are dispensable.  相似文献   
83.
The presence of a nonvibratory segment of vocal folds after microlaryngeal surgery is often a cause of poor voice result. The etiology of a nonvibratory segment is due to full thickness epithelial defect followed by secondary wound closure and scar contracture. To reduce scar contracture and nonvibratory segment of the vocal folds, primary repair with a 6-0 chromic endo-knot suture technique was used to close defects and approximate microflaps of the vocal folds. This was done in 18 patients with epithelial defects after resection of benign vocal fold lesions. The pathologic findings included severe polypoid degeneration (n = 7), fusiform laryngeal polyps (n = 5), sulcus vocalis (n = 2), cyst (n = 2), and keratosis (n = 2). Voice was improved in all patients after surgery. Comparison of vocal fold vibration before and after surgery showed improvements in configuration, amplitude, and mucosal wave. Vocal folds that were sutured all had good vibratory characteristics; none had a nonvibrating segment at the site of suture placement. Voice and healing after microsuture technique were near normal by Day 10 and return of mucosal wave was often complete by Day 14. Endoscopic microsuture closure of microflaps of the vocal folds edge is safe and affords the surgeon an opportunity for primary repair with improved functional result.  相似文献   
84.
本文介绍了单部件系统维修策略问题的建模方式。  相似文献   
85.
慈溪市1997年开始实施城区河道治理工程,由于种种原因,在城河治理工程中,出现了污水渠等构筑物渗漏污水的现象.综合分析了各种渗漏出现的原因,详细介绍了处理办法,分析评价了处理效果,并提出通过改进设计、加强管理来控制渗漏的建议、  相似文献   
86.
87.
介绍了治疗顽固性扁平疣的有效方法。本例患者起病两年多来由右手中指背针尖大的一个部位,发展到三个部位,且右中指创面发展到整个指甲边缘。期间曾行冷冻治疗、电灼治疗多次,内服、外用及肌注药物多种,均未奏效。最终行病灶切除缝合及侧胸部带蒂皮瓣移植,术后半年复查病灶未复发。可见手术切除方法是根治顽固性扁平疣的有效方法,侧胸部皮瓣为手指创面修复较理想部位。  相似文献   
88.
Defects were created on the surface of highly oriented pyrolytic graphite (HOPG) by sputtering with an Ar+ ion beam, then characterized using X‐ray photoelectron spectroscopy (XPS) and time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) at 500°C. In the XPS C1s spectrum of the sputtered HOPG, a sp3 carbon peak appeared at 285.3 eV, representing surface defects. In addition, 2 sets of peaks, the Cx and CxH ion series (where x = 1, 2, 3...), were identified in the ToF‐SIMS negative ion spectrum. In the positive ion spectrum, a series of CxH2+• ions indicating defects was observed. Annealing of the sputtered samples under Ar was conducted at different temperatures. The XPS and ToF‐SIMS spectra of the sputtered HOPG after 800°C annealing were observed to be similar to the spectra of the fresh HOPG. The sp3 carbon peak had disappeared from the C1s spectrum, and the normalized intensities of the CxH and CxH2+• ions had decreased. These results indicate that defects created by sputtering on the surface of HOPG can be repaired by high‐temperature annealing.  相似文献   
89.
The DNA repair enzyme ALKBH2 is implicated in both tumorigenesis as well as resistance to chemotherapy in certain cancers. It is currently under study as a potential diagnostic marker and has been proposed as a therapeutic target. To date, however, there exist no direct methods for measuring the repair activity of ALKBH2 in vitro or in biological samples. Herein, we report a highly specific, fluorogenic probe design based on an oligonucleotide scaffold that reports directly on ALKBH2 activity both in vitro and in cell lysates. Importantly, the probe enables the monitoring of cellular regulation of ALKBH2 activity in response to treatment with the chemotherapy drug temozolomide through a simple fluorescence assay, which has only previously been observed through indirect means such as qPCR and western blots. Furthermore, the probe provides a viable high‐throughput assay for drug discovery.  相似文献   
90.
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