黄陵矿区富油煤焦油产率特征及主控地质因素分析

笔者以各煤矿钻井、测井及勘探报告等资料为基础,采用井下调研、试验分析及数理统计等方法,结合前人的研究结果,对黄陇侏罗纪煤田黄陵矿区煤炭资源的煤层特征、煤的焦油产率特征、富油煤主控地质因素及资源潜力进行了详细分析和评价。研究结果表明,矿区主采煤层为2号和4-2号煤,属于中厚煤层。2号煤原煤焦油产率主要介于2.40%~13.40%之间,平均值为9.00%;4-2号煤原煤焦油产率主要介于5.20%~14.60%之间,平均值为9.23%,总体属于富油煤;矿区富油煤发育的主控地质因素为成煤沉积环境、成煤物质条件、煤化程度及煤显微组分等;高油煤在金咀沟、东方及党家河煤矿较发育,富油煤在党家河、集贤、牛石沟、黄陵二号及瑞能煤矿较发育。

中国海相不同类型原油与沥青生气潜力研究

本文通过固体沥青、沥青砂岩及加入不同介质原油与稠油的加水密闭热压模拟实验,对比研究了海相原油与沥青的气体产率特征、生气潜力及其影响因素。结果表明:原油与沥青的生气潜力除与岩性、演化程度有关外,还与其所含可溶有机质性质和组成等密切相关,H/C原子比越大,最大烃气产率越高,生烃气潜力越大。储集岩或运移途径岩石中的原油与沥青,当其再次达到成熟—高成熟阶段时,可以作为新的轻质油气或者天然气源岩。

Impact of grazing on soil, vegetation and ewe production performances in a semi-arid rangeland

Controlled grazing is considered a good management strategy to maintain or increase the live weight of livestock and to reduce vegetation degradation of rangelands. The present study investigated soil characteristics, aboveground vegetation biomass dynamics and controlled grazinginduced changes in the live weight of local ewes in the semi-arid rangeland of Ahmadun, Ziarat, Balochistanprovince of Pakistan. An area of 115 ha was protected from livestock grazing in April 2014. In June 2015, soil characteristics within 0-30 cm depth i.e. soil organic matter(SOM), mineral nitrogen, p H and texture in controlled and uncontrolled grazing sites were assessed. Aboveground vegetation biomass measured in early(June) and late summer(August) in 2015 and 2016. The nutritional value i.e. crude protein, phosphorus(P), neutral detergent fiber(NDF), acid detergent fiber(ADF), calcium(Ca), magnesium(Mg) and potassium(K) of dominantplant species were assessed at the beginning of experiment in 2015. Vegetation cover of controlled and uncontrolled grazing sites was also measured during the two years of the study period using the Veg Measure software. From June to November in2015 and 2016, controlled and uncontrolled livestock grazing sites were grazed on a daily basis by local ewes with a stocking rate of 2 and 1 head ha^(-1) respectively. Results reveal that the organic matter contents of coarse-textured, slightly alkaline soil of the study site were in the range of 9.4-17.6 g kg^(-1) soil and showed a strong positive correlation with aboveground vegetation biomass. The biomass of plants was 56.5% and 33% greater at controlled than uncontrolled grazing site in 2015 and 2016 respectively and plant cover was also higher at controlled than uncontrolled grazing site in both years The nutrient contents were significantly(P<0.05)lower in grasses than shrubs. In both years, the controlled grazing increased the weight gain of ewes about two folds compared to the uncontrolled grazing.The results indicate that controlled grazing improved the vegetation biomass production and small ruminant productivity.

Feature-based multiresolution techniques for product design

3D computer-aided design (CAD) systems based on feature-based solid modelling technique have been widely spread and used for product design. However, when part models associated with features are used in various downstream applications, simplified models in various levels of detail (LODs) are frequently more desirable than the full details of the parts. In particular, the need for feature-based multiresolution representation of a solid model representing an object at multiple LODs in the feature unit is increasing for engineering tasks. One challenge is to generate valid models at various LODs after an arbitrary rearrangement of features using a certain LOD criterion, because composite Boolean operations consisting of union and subtraction are not commutative. The other challenges are to devise proper topological framework for multiresolution representation, to suggest more reasonable LOD criteria, and to extend applications. This paper surveys the recent research on these issues.

Employment and Wage Effects of RMB Exchange Rate for Manufacturing Sectors in China and the US

By creating a labor market dynamic general equilibrium model, this paper derives the pass-through mechanism of exchange rate's employment and wage effects,carries out an empirical study on the employment and wage effects of RMB exchange rate for manufacturing sectors in China and the United States based on ridge regression, and examines the role of industry characteristics in this process. Research findings suggest that: RMB depreciation will drive employment and wage growth for most of China's laborintensive manufacturing sectors, and RMB appreciation will increase employment for certain capital-and technology-intensive sectors; but RMB depreciation has insignificant employment and wage effects for most sectors in the US. Hence, in achieving the longterm stability of RMB exchange rate, China should take advantage of RMB appreciation's manufacturing upgrade effect and ensure the steady growth of manufacturing employment.The US should make breakthroughs in various links of its economic development in order to tackle unemployment, instead of blaming RMB exchange rate. In addition, the nature of business activities and trade union characteristic are both significant factors that lead to differences in inter-sector employment levels of Chinese and US manufacturing sectors.Technology characteristic and other monopolistic characteristics exert decisive effects on the difference of wage return for various sectors in China and the US.

南方海相层系不同类型烃源(岩)生烃模拟实验及其产物同位素演化规律

利用常规高压釜热压模拟仪和仿真地层热压生排烃模拟仪对南方海相不同类型烃源进行生烃模拟实验,研究发现不同类型原油烃气产率最高,分散可溶有机质烃气产率次之,产率最低的为不同类型干酪根。不同类型烃源烃气产率与烃源的有机碳含量、可溶有机质含量高低、有机质类型有密切关系,与烃源原始成熟度具有较好负相关性。烃源碳同位素组成决定产物甲烷碳同位素组成的演化规律,碳同位素组成较轻的烃源其产物甲烷碳同位素组成总体上要轻于碳同位素组成较重烃源的甲烷碳同位素组成。不同类型烃源产物甲烷碳同位素组成随热模拟温度增高具有先变轻再变重的演化特征,但不会重于其烃源的碳同位素组成。乙烷等碳同位素组成也随着热模拟温度增高逐渐变重,演化至生烃高峰时,碳同位素组成接近于其烃源碳同位素组成,可以示踪烃源。当演化至高过成熟阶段,乙烷等δ13C值大于其烃源碳同位素值,故不能仅用重烃碳同位素组成判断天然气母质类型。不同类型干酪根与可溶有机质CO2组分和同位素组成演化规律具有明显区别,可溶有机质生成的CO2和甲烷之间同位素分馏程度要比不同类型干酪根的大。在不同类型烃源生烃过程中,干酪根和液态烃碳同位素组成主要受母质类型控制,继承效应强,同位素分馏程度较小,具有很好的示踪意义,可以用于油源对比和烃源示踪研究。

Interaction between strain and vorticity in compressible turbulent boundary layer

The interaction of strain and vorticity in compressible turbulent boundary layers at Mach number 2.0 and 4.9 is studied by direct numerical simulation(DNS)of the compressible Navier-Stokes equations.Some fundamental characteristics have been studied for both the enstrophy producing and destroying regions.It is found that large enstrophy production is associated with high dissipation and high enstrophy,while large enstrophy destruction with moderate ones.The enstrophy production and destruction are also correlated with the dissipation production and destruction.Moreover,the enstrophy producing region has a distinct tendency to be‘sheet-like’structures and the enstrophy destroying region tends to be‘tube-like’in the inner layer.Correspondingly,the tendency to be‘sheet-like’or‘tube-like’structures is no longer obvious in the outer layer.Further,the alignment between the vorticity vector and the strain-rate eigenvector is analyzed in the flow topologies.It is noticed that the enstrophy production rate depends mainly on the alignment between the vorticity vector and the intermediate eigenvector in the inner layer,and the enstrophy production(destruction)mainly on the alignment between the vorticity vector and the extensive(compressive)eigenvector in the outer layer.