论帕累托排列图在塑料门窗企业中的应用

在塑料门窗产品的成本中,原材料费占有较高比例。因此,采用科学合理的方法,来提高物资管理水平对塑料门窗企业来说,就显得非常重要。本文就帕累托排列图在塑料门窗企业物资管理中的应用问题进行探讨,以寻求更佳的物资管理方法,不断提高企业管理水平,进一步提高企业的经济效益。

挤压拉伸管毛料铸锭长度的计算

本文针对《轻金属材料加工手册》中计算挤压拉伸管毛料铸锭长度公式的不足之处,提出了修正意见和计算挤压拉伸管毛料铸锭长度的公式,并举例验证说明。

Stability control of underground construction

This paper presents the reason for instability of underground construction. In order to know failure mechanism during the whole construction process, a research framework of multi-scale based on experiments and numerical analysis is established. Some promising aspects in the topics of stability control are also given in the paper.

Spatial Scale Effects of Water Erosion Dynamics:Complexities, Variabilities, and Uncertainties

Severe water erosion is notorious for its harmful effects on land-water resources as well as local societies. The scale effects of water erosion, however, greatly exacerbate the difficulties of accurate erosion evaluation and hazard control in the real world. Analyzing the related scale issues is thus urgent for a better understanding of erosion variations as well as reducing such erosion. In this review article, water erosion dynamics across three spatial scales including plot, watershed, and regional scales were selected and discussed. For the study purposes and objectives, the advantages and disadvantages of these scales all demonstrate clear spatial-scale dependence. Plot scale studies are primarily focused on abundant data collection and mechanism discrimination of erosion generation, while watershed scale studies provide valuable information for watershed management and hazard control as well as the development of quantitatively distributed models. Regional studies concentrate more on large-scale erosion assessment, and serve policymakers and stakeholders in achieving the basis for regulatory policy for comprehensive land uses. The results of this study show that the driving forces and mechanisms of water erosion variations among the scales are quite different. As a result, several major aspects contributing to variations in water erosion across the scales are stressed: differences in the methodologies across various scales, different sink-source roles on water erosion processes, and diverse climatic zones and morphological regions. This variability becomes more complex in the context of accelerated global change. The changing climatic factors and earth surface features are considered the fourth key reason responsible for the increased variability of water erosion across spatial scales.

The Onset of the Monsoon over the Bay of Bengal:The Year-to-Year Variations

In situ buoy observation data spanning four years(2008-2011) were used to demonstrate the year-to-year variations of the monsoon onset processes in the Bay of Bengal(BoB).A significant early(late) monsoon onset event in 2009(2010) was analyzed in detail.It is found that the year-to-year variations of monsoon onset can be attributed to either the interannual variability in the BoB SST or the irregular activities of the intra-seasonal oscillation(ISO).This finding raises concern over the potential difficulties in simulating or predicting the monsoon onset in the BoB region.This uncertainty largely comes from the unsatisfactory model behavior at the intra-seasonal time scale.

Critical Dimension for Stable Self-Gravitating Stars in AdS

We study the self-gravitating stars with a linear equation of state, P = aρ, in AdS space, where a is a constant parameter. There exists a critical dimension, beyond which the stars are always stable with any central energy density; below which there exists a maximal mass configuration for a certain central energy density and when the central energy density continues to increase, the configuration becomes unstable. We find that the critical dimension depends on the parameter a, it runs from d = 11.1429 to 10.1291 as a varies from a = 0 to 1. The lowest integer dimension for a dynamically stable self-gravitating configuration should be d = 12 for any a E [0, 1] rather than d = 11, the latter is the case of self-gravitating radiation configurations in AdS space.

Fine-scale spatial distribution of soil organic carbon and its fractions after afforestation with Pinus sylvestris and Salix psammophila in a semiarid desert of China

Afforestation is helpful to improve soil functions and increase soil organic carbon(SOC)sequestration in semiarid deserts.However,the fine-scale(around a single plant)spatial distribution of SOC and its liable organic carbon(LOC)fractions after afforestation in semiarid deserts are poorly understood.Pinus sylvestris and Salix psammophila afforested on shifting sandy land(Sland)were selected to quantify fine-scale(at 20,80,150 and 240 cm away from the trees)spatial distribution of SOC and its LOC fractions in the southeast edge of Mu Us Desert,China.The results showed that the afforested S.psammophila and P.sylvestris significantly increased SOC,total nitrogen,dissolved organic carbon,microbial biomass carbon and readily oxidized organic carbon(ROOC).At 20 cm distance,SOC storage of P.sylvestris was 27.21%higher than S.psammophila in 0-100 cm soil layers,and SOC storage of S.psammophila at 80 and 150 cm distances was 5.50%and 5.66%higher than P.sylvestris,respectively.Compared with Sland,SOC storage under S.psammophila and P.sylvestris significantly increased by 94.90%,39.50%,27.10%and 18.50%at 20,80,150 and 240 cm distance,respectively.ROOC accounted for 14.09%and 18.93%of SOC under S.psammophila and P.sylvestris,respectively.Our results suggest that afforestation can promote SOC accumulation at different distances from the plants,and that P.sylvestris allocates more organic matter to the closer soil compared with S.psammophila(<80 cm from the tree).