西安流转农地与非流转农地利用效率对比评价

结合西安实地调研结果,构建了农业用地利用效率评价指标体系,运用熵值法评价模型,对流转农地与非流转农地利用效率进行了对比评价。结果表明,农地流转有助于提高农业用地利用效率,但是流转地的利用效率仍需进一步提高。

土地承包经营权非流转情形下的规模经营研究——以洞口县“香芝然”米业有限公司的经营模式为例

农业的产业化、规模化、商品化、集约化经营需要土地的成片规模化,这与家庭联产承包责任制的分散、细碎的土地耕作方式不相适应。洞口县"香芝然"米业公司在没有流转农民土地承包经营权的情形下,采取了"公司+基地+农户"的经营模式,实行了粮食产业的规模经营。土地承包经营权在公司与农户之间搭上了一座崭新的桥梁,它不仅稳定土地承包经营权和没有改变农业土地的用途,而且在解决"三农"问题、保护农用土地资源、促进土地承包经营权流转方面有积极作用。这种经营模式是土地规模经营的一种创新。

非粮化土地流转对粮食生产土地成本的实证分析

粮食生产土地成本持续走高成为既定事实,且土地快速流转与土地成本上涨呈相同趋势。基于粮食品种层面的885个宏观数据,将土地流转分为粮食化土地流转和非粮化土地流转,实证分析非粮化土地流转对粮食生产土地成本(流转地租金和自营地折租)的影响。研究表明,非粮化土地流转显著负向影响粮食生产的土地成本、流转地租金和自营地折租,而粮食化土地流转则显著正向影响粮食生产的土地成本和流转地租金,对自营地折租的影响不显著。机制分析表明,非粮化土地流转分别提高了土地流转中采用股份合作方式的比重及土地流转中土地流入合作社的比重,从而降低了粮食生产的土地成本。因此,需适当调控两类土地流转的比重,土地流转的种植结构不能“一刀切”;同时,支持各地区通过组织创新推进股份合作方式的土地流转,并发挥好新型农业经营主体中合作社的作用。结论为有效降低粮食生产土地成本提供实证依据。

浅论森林资源非规范性流转所引发的矛盾纠纷及其化解对策——以福建省三明市为例

针对三明市森林资源非规范性流转矛盾纠纷日益凸现及其严重影响林区社会稳定等突出问题,在对三明市森林资源非规范性流转历史与现状的调查基础上,分析了当前矛盾纠纷的形势、特点和主要诱因,提出了化解矛盾纠纷的建设性对策,为有效解决类似矛盾纠纷问题,提供决策参考。

论我国流转课税制度的改革

流转税是以流转额为课税对象而设计征收的税种统称,流转额包括商品流转额和非商品流转额。我国现行流转税制主要设置四个税种,即增值税、消费税、营业税和关税。流转税作为整个税收制度中的重要组成部分,具有不同于其他税类的特点。

什么是“流转税”、“增值税”、“价内税”、“价外税”

流转税:以纳税人的商品流转额和非商品流转额为征收对象的一类税收。其中商品流转额指商品交换金额对销售商品的一方表现为销售收入额,对购进商品的一方表现为采购支付金额。非商品流转额指各种劳务收入和服务性业务收入金额。我国现行的产品税、增值税、特别消费税、营业税统称叫流转税。今年的新税制中的增值税、消费税和营业税也叫流转税。

EXPERIMENTAL INVESTIGATION ON FLOW AND HEAT TRANSFER CHARACTERISTICS IN TENON JOINT GAP BETWEEN TURBINE BLADE AND DISK

The now and heat transfer characteristics in tenon joint gap between turbine blade and disk have been investigated experimentally with a scale up model. The characteristics of flow and heat transfer in this speCial gap passage have been analyzed. The results are useful for beat transfer analysis in turbine design.

相关支出所得税税前扣除依据的探析

虽然现行《企业所得税法》及其实施条例,并没有对有关支出的扣除依据进行明确规定和解释,但依据《国家税务总局关于加强企业所得税管理若干问题的意见》(国税发〔2005〕50号)规定:"不能提供真实、合法、有效凭据的支出,一律不得税前扣除。"国税发〔2008〕40号文:对于不符合规定的发票和其他凭证,包括虚假发票和非法代开发票,均不得用以税前扣除、出口退税和抵扣税款。那么,在经济业务真实发生的基础上,应该取得什么样的凭据,才算真实、合法、有效?才能作为企业所得税税前扣除依据呢?本文就此对相关支出税前扣除依据展开分析和探讨。

Local Liquid Side Mass Transfer Model in Gas-Liquid-Solid Three-Phase Flow Airlift Loop Reactor for Newtonian and Non-Newtonian Fluids

A small scale isotropic mass transfer model was developed for the local liquid side mass transfer coefficients in gas-liquid-solid three-phase flow airlift loop reactor for Newtonian and non-Newtonian fluids. It is based onHigbie's penetration theory and Kolmogoroff's theory of isotropic turbulence withwhere ε1 is local rate of energy dissipation, Af is the local microscale, η1 is the local Kolmogoroff scale and D is the diffusion coefficient. The capability of the proposed model is discussed in the light of experimental data obtained from 12 L gas-liquid-solid three-phase flow airlift loop reactor using Newtonian and non-Newtonian fluids. Good agreement with the experimental data was obtained over a wide range of conditions suggesting a general applicability of the proposed model.

名词解释

公开市场业务指中央银行在市场上买卖各种证券。它是市场经济体制下中央银行调节商业银行准备金数额和准备金(占存款的)比例,以调节货币供应量中的主体——存款货币量的一种货币政策。当它买证券时,商业银行的准备金就会增多;卖证券时,商业银行的准备金就会减少。这一买一卖,最终导致市场上货币量的膨胀与收缩。这是一种中央银行经常采用的货币政策。其显著特点在于:(1)这是一种效果较确定的货币政策。其原因在于。

Statistical analysis of pressure fluctuations during unsteady flow for low-specific-speed centrifugal pumps

A three-dimensional transient numerical simulation was conducted to study the pressure fluctuations in low-specific-speed centrifugal pumps. The characteristics of the inner flow were investigated using the SST k-ω turbulence model. The distributions of pressure fluctuations in the impeller and the volute were recorded, and the pressure fluctuation intensity was analyzed comprehensively, at the design condition, using statistical methods. The results show that the pressure fluctuation intensity increases along the impeller streamline from the leading edge to the trailing edge. In the impeller passage, the intensity near the shroud is much higher than that near the hub at thc inlet. However, the intensity at the middle passage is almost equal to the intensity at the outlet. The pressure fluctuation intensity is the highest at the trailing edge on the pressure side and near the tongue because of the rotor-stator interaction. The distribution of pressure fluctuation intensity is symmetrical in the axial cross sections of the volute channel. However, this intensity decreases with increasing radial distance. Hence, the pressure fluctuation intensity can be reduced by modifying the geometry of the leading edge in the impeller and the tongue in the volute.

Effects of China's BT-to-VAT Reform on Listed Companies' Turnover Tax Burden

Using the data of China's listed companies during 2010-2014 as samples, this paper employs the PSM and DID methods to respectively investigate the effects of BTto-VAT reform on the turnover tax burden for companies in pilot regions(Shanghai and eight other provinces and municipalities) and the rest of China. Our study arrived at the following findings: Compared with pilot sectors in non-pilot regions, BT-to-VAT reform has no significant effect on the turnover tax burden of pilot companies in pilot regions; compared with non-pilot companies, BT-to-VAT reform slightly increased the turnover tax burden in the short run and somewhat reduced the turnover tax burden for pilot companies in the long run. Further differentiation of ownership nature led to the discovery that BT-toVAT reform somewhat reduced the turnover tax burden of SOEs and central SOEs, slightly increased the turnover tax burden for non-SOEs and local SOEs in pilot regions, slightly increased the turnover tax burden in the short run and somewhat reduced the turnover tax burden in the long run after nationwide pilot programs were introduced; BT-to-VAT reform has more significant effects on non-SOEs and local SOEs. In general, BT-to-VAT reform has no significant effects on the turnover tax burden of companies and after differentiating pilot regions, pilot sectors and ownership nature, we did not discover any significant effect, which is generally consistent with policy expectations.

Numerical simulation on rotordynamic characteristics of annular seal under uniform and non-uniform flows

Currently, the flow field of annular seals disturbed by the circular whirl motion of rotors is usually solved using computational fluid dynamics(CFD) to evaluate the five rotordynamic coefficients. The simulations are based on the traditional quasi-steady method. In this work, an improved quasi-steady method along with the transient method was presented to compute the rotordynamic coefficients of a long seal. By comparisons with experimental data, the shortcomings of quasi-steady methods have been identified. Then, the effects of non-uniform incoming flow on seal dynamic coefficients were studied by transient simulations. Results indicate that the long seal has large cross stiffness k and direct mass M which are not good for rotor stability, while the transient method is more suitable for the long seal for its excellent performance in predicting M. When the incoming flow is non-uniform, the stiffness coefficients vary with the eccentric directions. Based on the rotordynamic coefficients under uniform incoming flow, the linearized fluid force formulas, which can consider the effects of non-uniform incoming flow, have been presented and can well explain the varying-stiffness phenomenon.

试论流转额课税

利改税第二步改革实施后,我国已经和将要实行的有21个税种,形成了新的税收体系。其中按流转额课税的税种在收入中所占比重较大,不仅同国家的经济情况密切有关,而且同国家预算和人民生活也有直接联系。为了正确执行税收政策,加强税收管理,有必要对流转额课税加以研究。流转额课税的沿革我国由于长期处于封建社会的经济落后状态,实物税的形式持续的时间长久。到了周代,开始征收'关市之赋',即对经过关卡或上市交易的物品都要征税,相似于现在的营业税、交易税、关税;以及'山泽之赋',即对山上的伐木、采矿、狩猎,水上的捕渔等等,都要征税,相似于现在的产品税。这可说是我国最早出现的流转额课税。

Unsteady Flow Field under Surge and Rotating Stall in a Three-stage Axial Flow Compressor

The unsteady flow structure between rotor blade-to-blade passages in a three-stage axial flow compressor is experimentally investigated by detailed measurements of unsteady performance characteristics,casing wall pressure fluctuations and their wavelet analyses.The main feature of the test compressor is a capacity tank facility connected in series to the compressor outlet in order to supply compression and/or expansion waves from downstream of the compressor.Research attention is focused on the post-stall characteristics of the surge and rotating stall which occur simultaneously.The influence of the compressor operating point on the unsteady performance curve shows that the surge cycle changes irregularly depending on the steady-state resistance characteristics,and the results of the wavelet analyses of the wall pressure fluctuations suggest that the surge cycle may selectively be determined by the rotating stall cell structure within the rotor cascade.

Evolution of Unsteady Flow near Rotor Tip during Stall Inception

Previously the features of circumferential propagation of self-induced tip leakage flow unsteadiness for a low speed isolated axial compressor rotor in the authors' laboratory were discovered and investigated via numerical simulation,which only occurs below a critical stable flow point that is close to but not yet at the stall limit.Further in this paper,the detailed investigation on evolution of tip leakage flow during the throttling process into spike rotating stall was conducted by adopting the valve-throttling model.During this process,the development of the circumferential propagation of tip leakage flow unsteadiness was especially focused on.According to the unsteady characteristics of pressure signals,the evolvement of compressor flow field can be classified into four stages.As compressor throttled,the oscillation frequency of self-induced unsteady tip leakage flow decreased gradually,and thus resulted in the decrease of its circumferential propagation speed.The circumferential propagation of self-induced tip leakage flow unsteadiness is closely related with rotating instability.When the forward spillage of tip leakage flow at the leading edge occurred,the spike type rotating stall was initiated.Its flow struc-tures were given in the paper.

Unsteady Flow Characteristic of Low-Specific-Speed Centrifugal Pump under Different Flow-Rate Conditions

To investigate the unsteady flow characteristics in centrifugal pump, the flow field in a low-specific-speed centri- fugal pump with complex impeller is numerically simulated under different conditions. The RNG r-e turbulence model and sliding mesh are adopted during the process of computation. The results show that the interaction be- tween impeller and volute results in the unstable flow of the fluid, which causes the uneven distribution of pres- sure fluctuations around the circumference of volute. Besides the main frequency and its multiple frequency of pressure fluctuations in the centrifugal pump, the frequency caused by the long blades of complex impeller also plays a dominant role in the low-frequency areas. Furthermore, there exists biggish fluctuation phenomenon near the tongue. The composition of static pressure fluctuations frequency on the volute wall and blade outlet is similar except that the fluctuation amplitude near the volute wall reduces. In general, the different flow rates mainly have influence on the amplitude of fluctuation frequency in the pump, while have little effect on the frequency compo- sition.

Numerical Investigation of the Unsteady Tip Leakage Flow and Rotating Stall Inception in a Transonic Compressor

It is well known that tip leakage flow has a strong effect on the compressor performance and stability. This paper reports on a numerical investigation of detailed flow structures in an isolated transonic compressor rotor-NASA Rotor 37 at near stall and stalled conditions aimed at improving understanding of changes in 3D tip leakage flow structures with rotating stall inception.Steady and unsteady 3D Navier-Stokes analyses were conducted to investigate flow structures in the same rotor.For steady analysis,the predicted results agree well with the experimental data for the estimation of compressor rotor global performance.For unsteady flow analysis, the unsteady flow nature caused by the breakdown of the tip leakage vortex in blade tip region in the transonic compressor rotor at near stall condition has been captured with a single blade passage.On the other hand, the time-accurate unsteady computations of multi-blade passage at near stall condition indicate that the unsteady breakdown of the tip leakage vortex triggered the short length-scale-spike type rotating stall inception at blade tip region.It was the forward spillage of the tip leakage flow at blade leading edge resulting in the spike stall inception. As the mass flow ratio is decreased,the rotating stall cell was further developed in the blade passage.

Two equilibria of the Antarctic Circumpolar Current and its associated Meridional Overturning Circulation

The Antarctic Circumpolar Current (ACC) and its associated Meridional Overturning Circulation (MOC) is investigated through a nonlinear inertia theory model, which consists of two layers--an upper Ekman layer driven mainly by sea surface wind stress and a lower thermocline controlled by ideal fluid nonlinear equations which can be solved by identifying the form of the arbitrary functions. The results show that the thermocline has a two-equilibrium solution though given the same Ekman layer condition. Compared to the first equilibrium, the second one has a heavier intensity and deeper circulation, which seems more consistent with the existing data.