论企业会计政策的选择

企业会计政策在形式上表现为企业会计过程的一种技术规范,但其本质上却是经济和政治利益的博弈和制度安排。企业在进行会计政策选择时,常常是基于与各利益相关方合约的考虑,特别是与股东、债权人及政府合约的考虑。因此,本文提出为防止企业在进行会计政策选择时,由于偏向某一特定利益主体而出现偏差,应完善公司治理结构,提高会计政策的公允性。     

Dynamic Stabilization of Non-equity Strategic Alliance

Non equity Strategic Alliance is one of the middle organization forms between enterprises and the market. It is loosely coupled and agile based on the restriction and coordination by contract. Relative to Equity Strategic Alliance, it shows the agile character. But, this character causes the instability and complexity. The authors did a research of dynamic stabilization in Non-equity Strategic Alliance supported by the theories of institution equilibrium from New Institutional Economics. Presuming a control management institute M, the dynamic stabilization model of Non-equity Strategic Alliance under conditions of complete information and incomplete information is established. The author hopes to help Chinese enterprises establish Non equity Strategic Alliance was established under the changing environment.     

关于一类离散时间神经网络模型的稳定性

考虑一类离散时间神经网络模型的稳定性，得到了模型的平衡解是渐近稳定的充分必要条件。     

DMF—DMSO混合溶剂中多硫离子化学平衡的研究

采用分光光度法研究在二甲基甲酰胺（ＤＭＦ）和二甲亚砜（ＤＭＳＯ）混合溶剂中的多硫离子平衡表明，无论在Ｚ＝２或８／３的溶液中，当表现浓度减小时，都有利于多硫离子的降解。并且溶液中多硫离子之间的化学平衡，都随混合溶剂的组成变化，也即和介电常数有关．低介电常数有利于低聚合度的多硫自由基离子的存在．     

Degradation and sorption of atrazine, hexazinone and procymidone in coastal sand aquifer media

The degradation, sorption and transport of atrazine, hexazinone and procymidone in saturated coastal sand aquifer media were investigated in batch and column experiments. The pesticides were incubated with sterilised and non-sterilised groundwater or a mixture of groundwater and the aquifer material in the dark at 15 degrees C for 120 days. The estimated half-lives of the pesticides (and their ranges) in the mixture of groundwater and aquifer sand were 36 (31-40), 54 (40-77) and 84 (46-260) days for atrazine, procymidone and hexazinone, respectively. Compared with the relevant results for the groundwater-sand mixture phase, the estimated half-life of pesticides in the groundwater phase alone was shorter for procymidone (21 days) but longer for hexazinone (134 days); atrazine was not degraded in the groundwater phase. Chemical degradation appeared to have played the predominant role in the degradation of hexazinone and procymidone in the aquifer system, while both chemical and biological processes seemed to be important for the degradation of atrazine. Batch isothermal experiments were carried out at pH 4.6-4.7 to obtain sorption coefficients under equilibrium conditions. The isothermal data of the pesticides fitted well with the non-linear Freundlich function with an exponent of sorption coefficient that was greater than one. Contrary to reports in the literature, sorption of atrazine was the greatest, and procymidone was slightly more sorbed than hexazinone. A column experiment was conducted at a typical field-flow velocity of 0.5 m day(-1) over 60 days to study pesticide attenuation and transport in flow dynamic conditions. Retardation factors, R, derived from a two-site sorption/desorption model were 8.22, 1.76 and 1.63 for atrazine, procymidone and hexazinone, respectively. Atrazine displayed the lowest mobility and the mobility of procymidone was only slightly less than that of hexazinone, which is consistent with observations in the batch experiment. A possible explanation for these observations is that ionic atrazine is bound to oppositely charged ionic oxides, and ionic oxides have less effect on the sorption of the non-ionic procymidone. The significant tailing in the pesticide breakthrough curves (BTCs) in comparison with the bromide BTC, together with model-simulated results, suggests that the transport of the pesticides was under chemical non-equilibrium conditions with R values that were less than their equivalent values predicted using the batch equilibrium isothermal data. As a result of non-linear kinetic sorption, retardation factors of the pesticides in groundwater systems would not be constant and will decrease with decreasing pesticide concentrations and increasing flow velocities. Hence, the use of equilibrium isotherm data will probably over-predict the sorption of pesticides in groundwater systems. Rhodamine WT, a commonly used groundwater tracer, was significantly retarded (R = 5.48) and its BTC was much more spread out than the bromide BTC. Therefore, it would not be a good tracer for the indication of groundwater flow velocity and dispersion for the coastal sand aquifer system. In contrast to some aquifer media, the dye tracer was unsuitable as a marker of the appearance of atrazine in a coastal sand aquifer system.     

宁南黄土丘陵区旱地作物水分平衡特征与水分生态适应性研究

依据田间试验结果 ,对宁南黄土丘陵区主要作物水分平衡特征与水分生态适应性进行定量评价。结果表明 ,夏熟作物全生育期水分满足率 ,干旱年份为 5 5 9%～ 6 3 8% ,丰水年份为84 1%～ 86 4 % ;秋熟作物全生育期水分满足率 ,干旱年份为 6 7 7%～ 79 0 % ,丰水年份为92 1%～ 95 1%。水分生态适应性因作物类型和降水条件而存在差异 ,秋熟作物水分生态适应性指数高于夏熟作物 ,丰水年份的作物水分生态适应性指数高于干旱年份。旱地 6种主要作物的水分生态适应性指数排序依次为 :谷子 >马铃薯 >糜子 >胡麻 >豌豆 >春小麦。研究结果可为制定合理的旱区种植制度决策方案提供理论依据     

滇西北兰科植物海拔分布格局

根据实际调查和整理相关文献资料,确定滇西北兰科植物409种,其分布的海拔范围为650～4700m;并按400m划分海拔段,共9个梯度,分析其垂直分布格局。结果表明：滇西北兰科植物的垂直分布格局呈“中间膨胀型”或“单峰型”,随着海拔升高,各海拔段兰科植物的数量依次为92、167、194、223、192、159、129、58、32种,其中1051—3000m海拔范围的物种多样性较高;相邻海拔段兰科植物种类相似性系数较高,海拔段相隔越远,相似性系数越小;生活型以地生兰为主,1051～1450m海拔段附生兰种类较为丰富,1851～3450m海拔段地生兰种类较为丰富,各海拔段腐生兰种类较少;1851—2250m海拔段区系成分最多,物种数为223种,占该区域兰科植物总数的54．52％;该区域的区系平衡点在海拔2115m左右,生活型平衡点在海拔2050m左右。     

多层住宅楼中实木地板实际含水率的调查

对南京市城区数栋多层住宅楼、近百户家庭安装的实木地板的含水率进行了实地调查.结果表明,朝南房间靠近窗口和阳台处的地板含水率均较低,朝北房间和客厅近窗口位置,地板的含水率较高;除了楼房底层,在相同楼层内同一树种实木地板的使用含水率差异不明显;含水率随楼层高度的增加而降低.调查结果为生产企业合理控制实木地板产品含水率范围提供参考.