会计档案管理浅谈

<正>会计档案是机关、团体和企事业单位财会部门在核算和监督经济业务活动中形成并按一定规律集中保存备查的原始会计核算文件材料。它是记录和反映经济活动的重要史料和证据,具有严格的数据平衡性、时序性和严肃性,是国家档案的重要组成部分。

长白山森林土壤剖面氨基糖的分布(英文)

研究了长白山土壤剖面中3种氨基糖的垂直分布规律及其对土壤有机质库的贡献,样品采自长白山北坡3个样点(海拔分别为600m,1680m和2580m).3种氨基糖对总氨基糖的贡献为氨基葡萄糖>氨基半乳糖>胞壁酸,剖面中氨基糖的含量及氨基糖对土壤有机质的贡献,在表层土壤中随土壤剖面深度增加而增加,但在矿质层中规律不同.不同纬度的氨基葡萄糖/胞壁酸比值与氨基葡萄糖/氨基半乳糖比值不同,说明它们来源于不同的微生物种群.

长期培肥黑土微生物量磷动态变化及影响因素

长期采用两种不同量有机肥 (M2 、M4)、化肥 (NPK)方式培肥黑土 ,研究微生物量P在作物生长季动态变化 .结果表明 ,施用有机肥微生物量P显著高于施用化肥 (NPK)和不施肥 (CK) ,微生物量P分别为M48 75～ 4 7 6 8mg·kg-1,M2 3 0 2～ 37 16mg·kg-1,NPK 1 5 9～ 10 6 2mg·kg-1,CK 0 76～ 6 74mg·kg-1之间 ,波动性较大 .M4、M2 处理微生物量P最大值出现在抽雄吐丝期 ,NPK、CK处理最大值出现在大喇叭口期 ;施肥数量和种类不同所引起的黑土微生物量P的差异并未因季节变化及玉米生育时期影响而明显改变 .微生物量P的动态变化与绝大多数黑土生物、理化特性指标的动态变化没有显著的相关性 ;微生物量P与黑土生物、理化特性 (除全钾外 ) ,植物氮、磷、钾含量有极显著的正相关关系 ,与黑土含水量呈显著正相关关系 .

呋喃丹对土壤酶活性的影响

通过模拟方法,研究了呋喃丹与土壤中3种重要水解酶类—土壤脲酶、转化酶和碱性磷酸酶的关系及其影响因素.结果表明:呋喃丹加入土壤后,土壤脲酶活性最初受到抑制,随培养时间的延长,呋喃丹的生态毒性逐渐降低,并最终激活脲酶;在0.3%呋喃丹浓度范围内,土壤脲酶、碱性磷酸酶和转化酶均被激活,且部分样品的转化酶活性与呋喃丹浓度呈显著或极显著正相关,说明转化酶活性可在一定程度上表征土壤受呋喃丹污染的程度,且0.3%浓度呋喃丹的生态毒性较弱,对土壤质量及生态环境比较安全.

土壤重金属生物淋滤修复过程中廉价碳源的筛选研究

在室内模拟实验条件下,重点研究了一步和二步生物淋滤过程中黑曲霉利用各种廉价碳源替代蔗糖产酸修复重金属污染土壤的效果。结果发现,杨树叶、桃树叶、土豆皮去除重金属效果较好。其中杨树叶对冶炼厂土壤中重金属去除率分别为Cu63.5%、Cd100%、Pb16.8%和Zn27%;桃树叶去除效果分别为Cu61.8%、Cd100%、Pb14.6%和Zn28.5%;土豆皮去除效果分别为Cu61%、Cd100%、Pb10.6%和Zn34%。廉价碳源的使用可降低污染土壤生物淋滤修复成本。

Microstructures and mechanical properties of as-cast Mg-5Y-3Nd-Zr-xGd (x=0, 2 and 4 wt.%) alloys

Mg-5Y-3Nd-0.6Zr-xGd (x = 0, 2 and 4 wt.%) alloys were prepared by metal mould casting technique, the structures and mechanical properties were investigated. The alloys were mainly composed of alpha-Mg solid solution and beta-phase. With increasing Gd content, Mg5RE phase increased and the grain was refined. The Mg-5Y-3Nd-2Gd-0.6Zr alloy exhibited highest ultimate tensile strength and Mg-5Y-3Nd-0.6Zr alloy showed highest yield strength at room temperature. With increasing amount of Gd, the thermal resistance was improved. The Mg-5Y-3Nd-4Gd-0.6Zr alloy exhibited highest UTS and YS at 250 degrees C, they were about 1.27 times higher than those of Gd-free alloy, which was mainly attributed to the increase of the beta-phase and Mg5RE strengthening phase.

A polymorph of diaquabis(pyrazine-2-carboxylato-kappa N-2(1),O)copper(II)

The title compound, [Cu(C5H3N2O2)(2)(H2O)(2)], is a new polymorph of the previously reported compound [Klein et al. (1982). Inorg. Chem. 21, 1891-1897]. The Cu-II atom, lying on an inversion center, is coordinated by two N atoms and two O atoms from two pyrazine-2-carboxylate ligands and by two water molecules in a distorted octahedral geometry with the water molecules occupying the axial sites. Intermolecular O-H center dot center dot center dot O, O-H center dot center dot center dot N and C-H center dot center dot center dot O hydrogen bonds connect the complex molecules into a two-dimensional layer parallel to (10 (1) over bar), whereas the previously reported polymorph exhibits a three-dimensional hydrogen-bonded network.

Bromophenols coupled with derivatives of amino acids and nucleosides from the red alga Rhodomela confervoides

Three new bromophenols coupled with pyroglutamic acid derivatives and one bromophenol coupled with deoxyguanosine were obtained from the red alga Rhodomela confervoides. By spectroscopic methods including 2D NMR and single-crystal X-ray structure analysis their structures were elucidated as N-(2,3-dibromo-4,5-dihydroxybenzyl)methyl pyroglutamate (1), N-(2,3-dibromo-4,5-dihydroxybenzyl)pyroglutamic acid (2), N-[3-bromo-2-(2,3-dibromo-4,5-dihydroxybenzyl)-4,5-dihydroxybenzyllmethyl pyroglutamate (3), and 2-N-(2,3-dibromo-4,5-dihydroxybenzylamino)deoxyguanosine (4), respectively. Compounds 1-4 were evaluated against several microorganisms and human cancer cell lines, but found inactive. To our knowledge this is the first report of bromophenols coupled with amino acid or nucleoside derivatives through the C-N bond.

滑动控制理论在海洋机器人动态定位系统中的应用

本文论述了一种新的鲁棒性控制方法——滑动控制理论.并将该方法应用于海洋机器人的动态定位系统设计.仿真结果表明该方法是相当成功和有效的,对系统的参数变化有强鲁棒性.

喀斯特森林群落退化对浅层岩溶地下水化学的影响

对贵州中部喀斯特地区植被调查及径流和岩溶水样分析,探讨喀斯特森林群落退化过程中浅层岩溶地下水化学组成的变化。结果表明:喀斯特森林生态系统降雨中离子浓度大小的排序为SO2 -4 > K+ 、Ca2 + 、HCO-3 >Na + 、Mg2 + 、Cl - > NO-3 、NH+4 > PO3 -4 ,而径流中离子浓度的大小排序为HCO-3 > SO2 -4 Ca2 + > Mg2 + 、Cl - > K+ 、Na + 、NO-3 > NH+4 > PO3 -4 ;岩溶地下水离子组成与径流总体相似,但岩溶地下中HCO-3 、Ca2 + 和Mg2 + 的含量及电导率明显增加高于地表径流。随着喀斯特森林群落从阔叶林群落向灌木林群落、灌草群落方向演替,其岩溶地下水中HCO-3 和Ca2 + 比例明显减少,而SO2 -4 比例明显增加。岩溶地下水的HCO-3 、Ca2 + 含量与森林覆盖率之间存在显著的正相关,而K+ 、NH+4 含量与森林覆盖率之间则存在显著的负相关。HCO-3 含量是影响岩溶地下水电导率的最重要因子,其次是Ca2 + ,再次是K+ 、Mg2 + ;岩溶地下水电导率可以作为评价喀斯特森林群落退化对生态环境影响的数量指标。