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全微机化示波极谱仪的应用——地质样品中钨和钼的测定

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现代科学仪器 2000年第2期17卷 53-54页

作者：徐晓霞四川省国土资源厅成都岩矿测试中心成都610081

应用全微机化示波极谱仪 (简称JPS) ,测定地质样品中的微量钨、钼。在氯酸钾 -苯羟乙酸 -辛可宁 -硫酸体系中钨、钼的峰电位分别为 - 0 82V (***)、 - 0 4 2V (***) ,钨、钼浓度分别在 1 39× 1 0 -9～2 6× 1 0 -6mol/L、2 6... 详细信息

应用全微机化示波极谱仪 (简称JPS) ,测定地质样品中的微量钨、钼。在氯酸钾 -苯羟乙酸 -辛可宁 -硫酸体系中钨、钼的峰电位分别为 - 0 82V (***)、 - 0 4 2V (***) ,钨、钼浓度分别在 1 39× 1 0 -9～2 6× 1 0 -6mol/L、2 6× 1 0 -9～ 2 1× 1 0 -6mol/L范围内与峰电流呈线性关系。检出限为钨 1 3× 1 0 -9mol/L、钼 2 7× -10 mol/L。特有的剥谱技术和科学的软件数学处理及自动化寻峰读值 ,对于微量元素及复杂样品的测定 ,有其独到的优势。

关键词：全微机化法波极谱仪钨钼测定地质样品

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一种基于三支决策的移动云任务节能卸载方法

南京理工大学学报 2019年第4期43卷 447-454页

作者：徐晓霞姜春茂黄春梅哈尔滨师范大学计算机科学与信息工程学院

移动云计算卸载(MCCO)有效地利用云平台扩展了移动计算和存储能力。细粒度的考查这一过程会发现存在大量的异构性特征(如容忍程度不同等)和三支现象(如卸载时机、卸载内容等)。借助于三支决策及决策粗糙集的基本思想,提出一种面向延迟... 详细信息

移动云计算卸载(MCCO)有效地利用云平台扩展了移动计算和存储能力。细粒度的考查这一过程会发现存在大量的异构性特征(如容忍程度不同等)和三支现象(如卸载时机、卸载内容等)。借助于三支决策及决策粗糙集的基本思想,提出一种面向延迟容忍型任务的移动云计算节能卸载策略。针对网络质量的优劣,以能耗优化为目标,分别对到来的延迟容忍型任务做出立即卸载、延迟卸载和不卸载3种决策。对于网络性能较差或者成本较高(如4G流量)的情况,可以采取等待,即延迟卸载;如果任务在等待期间网络性能恢复,则开始卸载任务,若超过延迟容忍期限且网络质量仍然很差则在本地执行,而网络连接状态较好的时候可立即卸载。通过阈值的确定为后续到来的云任务的卸载提供策略参考,从而减少计算的复杂性,优化移动设备的服务水平。模拟实验结果表明,基于三支决策思想的卸载策略在满足用户服务水平的前提下,有效地降低了移动设备的能耗,进一步延长了设备的使用寿命。

关键词：三支决策移动云计算任务卸载能耗敏感

Biohythane production from two-stage anaerobic digestion of food waste:A review

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Journal of Environmental Sciences 2024年第5期139卷 334-349页

作者： Xiaona An Ying xu Xiaohu Dai State Key Laboratory of Pollution Control and Resource Reuse School of Environmental Science and EngineeringTongji UniversityShanghai 200092China Shanghai Institute of Pollution Control and Ecological Security Shanghai 200092China

The biotransformation of food waste(FW)to bioenergy has attracted considerable research attention as a means to address the energy crisis and waste disposal *** this end,a promising technique is two-stage anaerobic digestion(TSAD),in which the FW is transformed to biohythane,a gaseous mixture of biomethane and *** review summarises the main characteristics of FW and describes the basic principle of ***,the factors influencing the TSAD performance are identified,and an overview of the research status;economic aspects;and strategies such as pre-treatment,co-digestion,and regulation of microbial consortia to increase the biohythane yield from TSAD is ***,the challenges and future considerations associated with the treatment of FW by TSAD are *** paper can provide valuable reference for the improvement and widespread implementation of TSAD-based FW treatment.

关键词： Two-stage anaerobic digestion(TSAD) Food waste(FW) Methane production Hydrogen production

手术治疗糖尿病足患者下肢神经阻滞麻醉的护理体会

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双足与保健 2019年第24期28卷 35-37页

作者：徐晓霞济宁市第一人民医院麻醉手术部

目的通过观察手术治疗糖尿病足患者下肢神经阻滞麻醉效果观察,并进行护理体会总结,为手术治疗糖尿病足的麻醉效果提供依据。方法选取该院2018年1-12月在该院手术室实施手术治疗糖尿病足并实施下肢神经阻滞麻醉患者102例,其中2018年1-6... 详细信息

目的通过观察手术治疗糖尿病足患者下肢神经阻滞麻醉效果观察,并进行护理体会总结,为手术治疗糖尿病足的麻醉效果提供依据。方法选取该院2018年1-12月在该院手术室实施手术治疗糖尿病足并实施下肢神经阻滞麻醉患者102例,其中2018年1-6月50例患者为对照组,2018年7-12月52例患者为观察组,两组患者均实施常规护理,观察组在对照组基础上实施完整的麻醉配合护理,对比两组患者的麻醉效果、麻醉穿刺时间、起效时间及患者满意度。结果观察组麻醉穿刺时间、起效时间明显短于对照组,观察组麻醉效果及患者满意度高于对照组。结论为患者实施完整的麻醉护理配合,缩短了麻醉穿刺时间及麻醉起效时间,提高了麻醉效果,提高了患者满意度,值得推广。

关键词： P糖尿病足下肢神经阻滞麻醉护理

A stable staggered-grid finite-difference scheme for acoustic modeling beyond conventional stability limit

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Petroleum Science 2024年第1期21卷 182-194页

作者： Jing-Yi xu Yang Liu National Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing 102249China China University of Petroleum(Beijing) Karamay CampusKaramay 834000XinjiangChina

Staggered-grid finite-difference(SGFD)schemes have been widely used in acoustic wave modeling for geophysical *** improved methods are proposed to enhance the accuracy of numerical ***,these methods are inevitably limited by the maximum Courant-Friedrichs-Lewy(CFL)numbers,making them unstable when modeling with large time sampling intervals or small grid *** solve this problem,we extend a stable SGFD scheme by controlling SGFD dispersion relations and maximizing the maximum CFL ***,to improve modeling stability,we minimize the error between the FD dispersion relation and the exact relation in the given wave-number region,and make the FD dispersion approach a given function outside the given wave-number area,thus breaking the conventional limits of the maximum CFL ***,to obtain high modeling accuracy,we use the SGFD scheme based on the Remez algorithm to compute the FD *** addition,the hybrid absorbing boundary condition is adopted to suppress boundary reflections and we find a suitable weighting coefficient for the proposed *** derivation and numerical modeling demonstrate that the proposed scheme can maintain high accuracy in the modeling process and the value of the maximum CFL number of the proposed scheme can exceed that of the conventional SGFD scheme when adopting a small maximum effective wavenumber,indicating that the proposed scheme improves stability during the modeling.

关键词： Acoustic wave Staggered-grid finite-difference(SGFD) modeling Courant-friedrichs-lewy(CFL)number Stability

Comparison of Microwave Imaging Algorithms for Short-Range Scenarios

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Journal of Beijing Institute of Technology 2024年第3期33卷 227-236页

作者： Zhengyue Dong Ning xu Kuiwen xu Engineering Research Center of Smart Microsensors and Microsystems Ministry of EducationHangzhou Dianzi UniversityHangzhou 310018China

Three dimensional(3-D)imaging algorithms with irregular planar multiple-input-multiple-output(MIMO)arrays are discussed and compared with each *** on the same MIMO array,a modified back projection algorithm(MBPA)is accordingly proposed and four imaging algorithms are used for comparison,back-projection method(BP),back-projection one in time domain(BP-TD),modified back-projection one and fast Fourier transform(FFT)-based MIMO range migration algorithm(FFT-based MIMO RMA).All of the algorithms have been implemented in practical application scenarios by use of the proposed imaging *** to the practical applications,MIMO array-based imaging system with wide-bandwidth properties provides an efficient tool to detect objects hidden behind a *** MIMO imaging radar system,composed of a vector network analyzer(VNA),a set of switches,and an array of Vivaldi antennas,have been designed,fabricated,and ***,these algorithms have been applied to measured data collected in different scenarios constituted by five metallic spheres in the absence and in the presence of a wall between the antennas and the targets in simulation and pliers in free space for experimental ***,the focusing properties and time consumption of the above algorithms are compared.

关键词： multiple-input-multiple-output(MIMO) short-range imaging back projection modi-fied back propagation range migration algorithm(RMA) through-wall imaging

Formation estimation and evolution mechanism of the pressure arch for non-circular tunnels under asymmetrical stress field

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Science China(Technological Sciences) 2024年第9期67卷 2919-2938页

作者： SUN ZhenYu ZHANG DingLi xu Tong CHEN xu Key Laboratory for Urban Underground Engineering of Ministry of Education Beijing Jiaotong UniversityBeijing 100044China

The tunneling-induced stress redistribution is dependent on the tunnel shape and the in-situ stress field, and the previous arch characterization method based on the circumferential or maximum principal stresses is only suitable for the circular tunnels under the hydrostatic stress field. In this study, a unified characterization method of the pressure arch for non-circular tunnels under the arbitrary stress field is proposed. By comparing the variations of compressive stress in different directions due to excavation, the ratio of the most significant increase in compressive stress is presented to characterize the arch effect, and the corresponding numerical algorithm is given. Since the proposed method takes the stress element as the basic analytical model, it can be easily applied to various complex excavation situations. Thereafter, combined with the established folding catastrophic model, an objective and unified quantitative method of the pressure arch boundaries is given. Using the proposed method, the longitudinal evolution of the pressure arch is analyzed. According to the expansion rate of the arch boundaries, three evolution stages including the initial formation, rapid expansion and stabilization are categorized. Parametric studies are conducted to illustrate the effect of ground properties and support stiffness on the pressure arch formation. It is found that the ground strength parameters and burial depth affect the arch range at a decreasing rate, while they have little effect on the arch shape. The lateral pressure coefficient has a significant effect on both the shape and range of the pressure arch. Increasing the support stiffness helps reduce the pressure arch range with a decreasing rate, while the synchronous variation of the elastic moduli of the surrounding rock and support does not affect the arch range under a certain relative elastic modulus. Finally, field monitoring is conducted to validate the proposed method in actual support design.

关键词： pressure arch stress redistribution numerical simulation quantitative characterization longitudinal evolution parametric study

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巧用“能量守恒”速解电磁感应问题

物理教学探讨 2008年第8期26卷 30-31页

作者：徐晓霞沂源第一中学山东沂源县256100

能的转化和守恒定律自建立以来,就是人们认识自然和改造自然的有力武器。在今天,这一定律也是我们解决物理问题的重要武器。有些电磁感应问题,若从"能量守恒"的角度去分析,能别开生面,使问题迅速解决。下面列举几例,请同学们例参1考。

关键词：重力势能 ab 合外力匀强磁场能量守恒感应电流守恒定律匀速运动分界面金属棒

Identification of high oxygen-consuming substances in stormwater drainage systems illicitly connected with sewage system

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Journal of Environmental Sciences 2024年第4期138卷 132-140页

作者： Chen xu Zuxin xu Wenhai Chu Shanshan Wu Rong Xiao Lei Su State Key Laboratory of Pollution Control and Resource Reuse College of Environmental Science and EngineeringTongji UniversityShanghai 200092China Ministry of Education Key Laboratory of Yangtze River Water Environment Tongji UniversityShanghai 200092China Guangzhou Resource Environmental Protection Technology Co. Ltd.Guangzhou 510030China

The dissolved oxygen content in water is an important indicator for assessing the quality of the water environment,and maintaining a certain amount of dissolved oxygen is essential for the healthy development of the ecological *** a water body is anoxic,the activity of anaerobic microorganisms increases and organic matter is decomposed to produce a large number of blackening and odorizing substances,resulting in black and odorous water bodies,which is a very common and typical phenomenon in ***,there is still a relatively universal occurrence of illicitly connected stormwater and sewage pipes in the urban drainage pipe network in China,which makes oxygen-consuming substances be directly discharged into rivers through stormwater pipes and consume the dissolved oxygen in the water bodies,resulting in an oxygen deficiency of the *** induces seasonal or year-round black and stink phenomena in urban ***,identifying high oxygen-consuming substances,which lays the foundation for the subsequent removal of oxygen-consuming substances,is *** a series of comparisons of water quality indicators and analysis of organic characteristics,it was found that the oxygen consumption capacity of domestic sewage was higher than that of industrial wastewater in the selected area of this study,and the oxygen-consuming substances of domestic sewage were small molecular amino *** comparing 20 conventional free amino acids,it was found that seven of them consumed oxygen easily,and compared with chemical oxygen consumption,biological oxygen consumption was in a leading position.

关键词： Urban drainage system Oxygen-consuming substances Domestic sewage Amino acid