检索结果-南通市图书馆

Importance of storage time in mesophilic anaerobic digestion of food waste

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2016年第7期28卷 76-83页

作者： Fan lü Xian xu liming Shao Pinjing He State Key laboratory of Pollution Control and Resource Reuses Tongji University Institute of Waste Treatment and Reclamation Tongji University Centre for the Technology Research and Training on Household Waste in Small Towns & Rural Area Ministry of Housing and Urban–Rural Development of PR China

Storage was used as a pretreatment to enhance the methanization performance of mesophilic anaerobic digestion of food waste. Food wastes were separately stored for 0, 1,2, 3, 4, 5, 7, and 12 days, and then fed into a methanogenic reactor for a biochemical methane potential（BMP） test lasting up to 60 days. Relative to the methane production of food waste stored for 0–1 day（285–308 m l/g-added volatile solids（VSadded））, that after2–4 days and after 5–12 days of storage increased to 418–530 and 618–696 m l/g-VSadded,respectively. The efficiency of hydrolysis and acidification of pre-stored food waste in the methanization reactors increased with storage time. The characteristics of stored waste suggest that methane production was not correlated with the total hydrolysis efficiency of organics in pre-stored food waste but was positively correlated with the storage time and acidification level of the waste. From the results, we recommend 5–7 days of storage of food waste in anaerobic digestion treatment plants.

关键词： Food waste Bio-pretreatment Storage Fermentation Biochemical methane potential Hydrolysates

Weighted variation inequalities for differential operators and singular integrals in higher dimensions

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2017年第8期60卷 1419-1442页

作者： MA Tao TORREA Jose l. xu QuanHua School of Mathematics and Statistics Wuhan University Departamento de Matemticas Universidad Autónoma de Madrid Institute for Advanced Study in Mathematics Harbin Institute of Technology laboratoire de Mathematiques Universite de Franche-Comte Institut Universitaire de France

We prove weighted q-variation inequalities with 2lar integral operators in higher *** vector-valued extensions of these inequalities are also *** results are proven for differential ... 详细信息

We prove weighted q-variation inequalities with 2lar integral operators in higher *** vector-valued extensions of these inequalities are also *** results are proven for differential operators.

关键词： variation inequalities A_(p) weights differential operators singular integrals vector-valued variationin equalities

Cost effective approach to identify multiple influential spreaders based on the cycle structure in networks

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2023年第9期66卷 184-193页

作者： Wenfeng SHI Shuqi xu Tianlong FAN linyuan lü Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of China Institute of Dataspace Hefei Comprehensive National Science Center Department of Physics University of Fribourg Alibaba Research Center for Complexity Sciences Hangzhou Normal University

Identifying influential spreaders has theoretical and practical significance in complex *** centrality methods can efficiently find a single spreader, but it could lead to influence redundancy and high initializing costs when used to identify a set of multiple spreaders. A cycle structure is one of the most crucial reasons for the complexity of a network and the cornerstone of the feedback effect. From this novel perspective, we propose a new method based on basic cycles in networks to identify multiple influential spreaders with superior spreading performance and low initializing costs. Experiments on six empirical networks show that the spreaders selected by the proposed method are more scattered in the network and yield the best spreading performance compared with those on seven well-known methods. Importantly, the proposed method is the most cost effective under the same spreading performance. The cycle-based method has the advantage of generating multiple solutions. Our work provides new insights into identifying multiple spreaders and hence can benefit wide applications in practical scenarios.

关键词： multiple spreaders basic cycle complex network cycle structure spreading dynamics

Interannual and Interdecadal Variability of Winter Precipitation over China in Relation to Global Sea level Pressure Anomalies

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2002年第5期19卷 914-926页

作者： Jianjun xu Johnny C.l Chan Department of Physics&Materials Science City University of Hong KongChina Department of Earth&Environmental Science New Mexico Tech801 Leroy PlaceSocorro87801 New MexicoUSA

Based on the method of rotated principal component (RPC) analysis and wavelet transforms, the winter precipitation from 36 stations over China for the period 1881-1993 is examined. The results show that the three leading space-time modes correspond, in sequence, to winter rainfall anomalies over the reaches of the Yangtze River, the bend of the Yellow River, and the northeastern region of China. The three modes exhibit interannual oscillations with quasi-biennial and 8-year periods as well as interdecadal oscillations with 16- and 32-year periods. The interannual oscillation (< 10 years) occurs in phase over the different areas, and its maximum amplitude migrates northward considerably with prominent interdecadal variations. However, the interdecadal oscillations (10-32 years) are out of phase over the different regions, and the amplitude variations have the characteristics of stationary waves. The rainfall anomalies appear to be closely related to the anti-phase changes of mean sea-level pressure (SlP) over the Asian mainland and the North Pacific. When the SlP rises over the North Pacific and decreases over the Asian mainland, the precipitation over East China increases noticeably. The linkage between the rainfall over China and the SlP anomalies apparently results from the strength of the East Asian winter monsoon and its associated temperature and moisture advection.

关键词： wavelet transform winter precipitation China SlP

Aero-Acoustics of Modern Transonic Fans—— Fan Noise Reduction from Its Sources

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2003年第2期12卷 104-113页

作者： l.xu J.D.Denton Whittle laboratory University of CambridgeUKWhittle LaboratoryUniversity of CambridgeUK

The noise of aerodynamics nature from modern transonic fan is examined from its sources with the perspective of noise reduction through aero-acoustics design using advanced Computational Fluid Dynamics (CFD) tools. In particular the problems associated with the forward propagating noise in the front is addressed. It is identified that the shock wave spillage from the leading edge near the fan tip is the main source of the tone noise. Two different approaches have been studied to reduce the forward arc tone noise and two state-of-art transonic fans are designed using the strategies developed. The following rig tests show that while the fans exhibit other noise problems, the primary goals of noise reduction have been achieved through both fans and the novel noise reduction concept vindicated.

关键词： transonic fan aero-acoustics noise reduction.

Approach for electrodynamic force for compensation in low voltage circuit breaker WP 630-1.2 type

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第3期8卷 393-396页

作者： lU Na xu l.J Miedzifiski B Automation School Beijing University of Posts and Telecommunications Beijing 100876 China Electrical Power Engineering Institute Wroclaw University of Technology Wroclaw Poland

Undesirable repulsive force between contact members due to both a current path shrink near a real contact area and/or so-called pinch effect is particularly onerous for power switch applications, and results in either contact floating or bouncing which are associated with an electric arc following contact welding. This problem is of great importance for any circuit breaker especially for compact low voltage vacuum circuit breakers. To avoid contact floating at closure and during any inrush current under short circuit conditions, the electrodynamic repulsive force can be employed successfully if we use a special compensation system flexibly combined with the contact itself. However to select and design the compensation system properly, its efficiency has to be known. This paper presents an approach to obtain the electrodynamic force value depending on different shaped (rectangular, square, circle and arch) copper plates used in the compensator by using ANSYS for current values 40 kA RMS. Curve-fitting was done according to the calculating results, the optimization designing of compensation unit is based on them.

关键词： Compensation. Electrodynamic force. FEM (Finite Element Method)

RElIABIlITY ANAlYSIS FOR AN AERO ENGINE TURBINE DISK UNDER lOW CYClE FATIGUE CONDITION

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English letters) 2004年第4期17卷 514-520页

作者： C.l.liu Z.Z.lü Y.l.xu School of Aviation Northwestern Polytechnical University Xi'an 710072 ChinaSchool of Aviation Northwestern Polytechnical University Xi'an 710072 ChinaChina Aviation Research Institute 608 Zhuzhou 412002 China

Reliability analysis methods based on the linear damage accumulation law (lDAl) and load-life interference model are studied in this paper. According to the equal probability rule, the equivalent loads are derived, and the reliability analysis method based on load-life interference model and recurrence formula is constructed. In conjunction with finite element analysis (FEA) program, the reliability of an aero engine turbine disk under low cycle fatigue (lCF) condition has been analyzed. The results show the turbine disk is safety and the above reliability analysis methods are feasible.

关键词： low cycle fatigue life reliability analysis load-life interference model recurrence method aero engine turbine disk

Seismic damage to road networks subjected to earthquakes in Nepal,2015

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2017年第3期16卷 649-670页

作者： Xie Quancai lü Gaohu Chen Hao xu Chong Feng Biao Key laboratory of Earthquake Engineering and Engineering Vibration Institute of Engineering MechanicsChina Earthquake Administration CCCC Highway Consultants Co. Ltd. Institute of Geology China Earthquake Administration

The Gorkha earthquake in Nepal led to many landslides and severe damage to the transportation infrastructure. After careful comparison of the aerial photographs and satellite images before and after the earthquake, partially verified by a field study, more than 2,064 landslides and many road failures were observed. Many bridges, especially steel-truss and suspension bridges, suffered little damage from inertia loads during the earthquake, but were severely damaged due to rockfalls. Potential geological hazards hindered the delivery of supplies in mountainous areas, and road closures impeded the overall speed of rehabilitation.

关键词： Gorkha earthquake reconnaissance transportation landslide road network

经“O”点穿刺与传统单侧入路治疗l_(5)椎体骨质疏松性压缩性骨折

在线全文

学校读者我要写书评

暂无评论

中国组织工程研究 2025年第15期29卷 3165-3170页

作者：徐雨果黄家虎王清徐双王松西南医科大学附属医院骨科四川省泸州市646000 四川省科技城医院四川省绵阳市621000

背景:单侧穿刺入路经皮穿刺球囊扩张椎体后凸成形治疗骨质疏松性椎体压缩骨折优于双侧穿刺入路,由于l_(5)特殊解剖形态和位置特殊,传统单侧穿刺入路治疗l_(5)椎体骨质疏松性椎体压缩骨折适用性差,因此提出“O”点穿刺入路来解决该问题... 详细信息

背景:单侧穿刺入路经皮穿刺球囊扩张椎体后凸成形治疗骨质疏松性椎体压缩骨折优于双侧穿刺入路,由于l_(5)特殊解剖形态和位置特殊,传统单侧穿刺入路治疗l_(5)椎体骨质疏松性椎体压缩骨折适用性差,因此提出“O”点穿刺入路来解决该问题。目的:比较经横突基底部-椎弓根后上部-关节突外侧交点(“O”点)入路与传统单侧入路经皮穿刺球囊扩张椎体后凸成形治疗l_(5)椎体骨质疏松性压缩骨折的疗效差异。方法:回顾性分析西南医科大学附属医院2020年1月至2022年12月收治的54例l_(5)椎体骨质疏松性压缩骨折行经“O”点入路或传统经皮穿刺球囊扩张椎体后凸成形治疗的患者,根据手术方式分为2组,“O”点入路组(A组)29例,传统入路组(B组)25例。术前在X射线正位片测量A组“O”点与髂棘位置及穿刺角度;比较两组术前与术后第2天、末次随访的局部Cobb角、椎体前缘、中部高度及骨水泥分布情况;术前、术后第2天及末次随访采用疼痛目测类比评分、Oswestry功能障碍指数评估患者疼痛缓解情况与日常生活能力,记录手术相关并发症。结果与结论:①A组手术时间、术中透视次数均少于B组,差异有显著性意义(P0.05);⑤术后骨水泥分布,A组分布良好占97%(28/29),B组分布良好占88%(22/25),A组明显优于B组(Pl_(5)椎体骨质疏松性压缩骨折疗效满意,但“O”点穿刺入路经皮穿刺球囊扩张椎体后凸成形治疗骨水泥分布更满意,还可避免高髂棘对l_(5)椎体穿刺入路的影响。

关键词：骨质疏松性压缩骨折经皮穿刺椎体后凸成形 “O”点 l_(5)椎体骨水泥