运输问题求解算法的执行效率分析——阶石法与元素判别值分配法的比较

本文针对求解运输问题的阶石法与元素判别值分配法 ,通过具有代表性的检验数据 。

洛阳青年宫广场出土陛阶石的相关问题刍议

2019年9月,为了配合地铁1号线的建设,洛阳市文物考古研究院对青年宫广场南端进行了尝试性发掘,在距离地表约1.2米的深度,发现了一块体积庞大的石雕,经过初步确认,应是明代福王府陛阶石。其上有精美的龙形浮雕,并伴以雕工精湛的云纹,堪称非常出色的工艺精品。龙作为一种文化符号,几乎贯穿于整个中华文化的发展史,且具有鲜明的时代性特征。本文对该陛阶石进行了考证,对其归属、年代等相关问题做出初步判断。

使用平均包间延迟建立攻击连接链关联

当存在主动延迟干扰时,Wang Xinyuan等提出的基于包间延迟检测连接链相关性的算法不能正确检测相关连接,通过引入平均包间延迟取整值的概念提出优化算法,在攻击者主动干扰包间延迟的连接链中仍能检测相关性.实验表明:通过适当调整参数值,可使算法在存在主动延迟干扰的长连接链中有较好的有效性及健壮性.

Rock Weathering Tendency at Different Stages of Soil－Forming Processes in Fildes Peninsula， Antarctic

From the view of energy state of material, this paper introduces a concept of weathering potential in carrying out quantitative calculation of the relevant products at different stages of rock-weathering and primary soil-forming processes, elaborates respectively on weathering degree in the bio-weathering layer of rocks and during the formation of soil material and clay, and evaluats the further tendency of weathering in the above-mentioned stages. The authors have discovered that the scales of weathering potential of the materials increase successively in the three stages, which indicates that the products in the above-mentioned three stages must have undergone stronger and stronger weathering in the primitive forming process of soil in Fildes Peninsula, Antarctic. But, because of relatively weak chemical weathering, it is reasonable that there are much more skeleton grains and little clay in primary soils in this region. Meanwhile, the authors have also verified that the weathering potential of crude rock determines to some extent decrease in the products' weathering potential in the different stages in primary soil-forming, thereby plays an important role in the genesis and development of the primary soil in the studied area.

Age of Berh Hairhan Formation of Mongolia dated by conodonts

Conodont Caudicriodus angustus angustus （Steward et al. , 1956 ） and Catuticriodus angustus cauda （Wang et al. , 2005） were found from a big limestone lens of the Berh Hairhan Formation in the place of W 150 km to Ulaanbaatar City. The discovery indicates that the Beth Haihan Formation should be assigned to Middle Devonian Eifelian Stage. This conodont fauna was from a shallow cooler water facies in the relatively high latitude.

A Remote Sensing Characterization of the Effects of Anastrepha striata ＆ Anastrepha ludens on Guava Cultures in Mexico

Detection of the presence of Anastrepha striata and Anastrepha ludens in guava cultures is presently done in Mexico by actually catching the flies in strategically located traps. The objective of this study is to show that it is possible to locate areas with the presence or absence of flies by remote sensing means, thereby simplifying the traditional way of detection of these plagues. In the field, groups of traps were selected where flies had been captured, as well as areas in which there was no capture in the traps. The radiometric signatures of whole trees and leaves were obtained, showing measurable differences between those specimens affected by the plague and those unaffected. Next we selected a SPOT5 image of 2007 corresponding to the study area in Calvillo, State of Aguascalientes, in Mexico, one of the major areas of guava cultures in the country. A supervised classification of the image allowed for the location of guava cultures in it. The guava culture areas obtained from this classification were validated comparing them to available maps of the cultured areas. Spectral signatures for the classes were derived from the image data. The separability of pairs of classes was also evaluated in order to maximize it. The IR/R （infrared to red ratio） ratio of the image bands was evaluated in 80 × 80 pixels around the locations of five traps where flies had been captured, and around five locations where the traps had not captured flies. Only the pixels where guava cultures were present were included in the analysis, other types of vegetation and soil coverage were rejected. We found that the index distributions with flies captured and those without flies captured cluster in two well-separated groups. We note that plotting the whole distribution of pixels around a trap yields a diagnostic view of the area, and individual index values do not provide such a view, since values with the flies＇ presence and without these overlap to some extent. Further analyses of other trap locations confirmed this separation and also revealed a third group of intermediate values between the two above, that are interpreted as locations in which the guava cultures are affected by the plague at an early stage of development, where the flies are not captured by the traps since they do not yet hatch. We concluded that it is possible to use remote sensing techniques to identify the presence ofAnastrepha striata and Anastrepha ludens in cultures of Psidium guajava L., even probably at early stages of development of the plague.

Simulation of crack coalescence mechanism underneath single and double disc cutters by higher order displacement discontinuity method

The present research is focused on the numerical crack coalescence analysis of the micro-cracks and cracks produced during the cutting action of TBM disc cutters. The linear elastic fracture mechanics(LEFM) concepts and the maximum tangential stress criterion are used to investigate the micro crack propagation and its direction underneath the excavating discs. A higher order displacement discontinuity method with quadratic displacement discontinuity elements is used to estimate the stress intensity factors near the crack tips. Rock cutting mechanisms under single and double type discs are simulated by the proposed numerical method.The main purposes of the present modeling are to simulate the chip formation process of indented rocks by single and double discs.The effects of specific disc parameters(except speed) on the thrust force Ft, the rolling force Fr, and the specific energy ES are investigated. It has been shown that the specific energy(energy required to cut through a unit volume of rock) of the double disc is less than that of the single disc. Crack propagation in rocks under disc cutters is numerically modeled and the optimum ratio of disc spacing S to penetration depth Pd(i.e. S/Pd ratio) of about 10 is obtained, which is in good agreement with the theoretical and experimental results cited in the literature.

Building Envelopes and Energy

In this paper, for a sustainable building in a Mediterranean climate areas, the relation between envelope and energy is discussed. The relation between envelopes and energy has been considered in all the phases of the life building （construction phase and during operation）. This has been made through global assessment of massive envelopes （with or without insulation） realized with blocks of different materials： natural stone, concrete and brick. For these types of envelope the thermal comfort of the rooms, the energy requirement for cooling and heating, economic and environmental aspects （costs and embodied energy） in the life cycle of the building have been studied.

High capacity lithium-manganese-nickel-oxide composite cathodes with low irreversible capacity loss and good cycle life for lithium ion batteries

We report a method to eliminate the irreversible capacity of 0.4Li_2MnO_3·0.6LiNi_(0.5)Mn_(0.5)O_2(Li_(1.17)Ni_(0.25)Mn_(0.583)O_2) by decreasing lithium content to yield integrated layered-spinel structures.XRD patterns,High-resolution TEM image and electrochemical cycling of the materials in lithium cells revealed features consistent with the presence of spinel phase within the materials.When discharged to about 2.8 V,the spinel phase of LiM_2O_4(M=Ni,Mn) can transform to rock-salt phase of Li_2M_2O_4(M=Ni,Mn) during which the tetravalent manganese ions are reduced to an oxidation state of 3.0.So the spinel phase can act as a host to insert back the extracted lithium ions(from the layered matrix) that could not embed back into the layered lattice to eliminate the irreversible capacity loss and increase the discharge capacity.Their electrochemical properties at room temperature showed a high capacity(about 275 mAh g^(-1) at 0.1 C) and exhibited good cycling performance.