19 research outputs found

    Revenue Risk Management ——Taking The National Tax Administration in Knitting Industry in ChangLe FuZhou as a Study Case

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    摘要 随着经济全球化和我国工业化、信息化、城镇化、市场化、国际化的深入发展,纳税人数量不断增多,企业经济性质、组织形式、经营方式呈现多样化,这些发展趋势都使得税收管理上人少户多、税务干部的素质跟不上形势的发展等方面的矛盾加剧,再加上传统单一的税收管理员的管理方式和粗放的税源管理模式,使得税收风险不断加大。如何控制和降低税收风险?税收风险管理理论适应了形势发展的需要,逐渐为人们所接受。 税收风险管理就是寻找可能导致税收风险的不确定因素,针对这些不确定因素,通过对风险的识别、评估、提出解决方案、对税务机关内部有限的管理资源的合理配置和优化,以及促使企业纳税遵从度最大化等系统的举措,以达到使税收...Abstract With the economic globalization and our country’s further development of industrialization、informatization、urbanization、marketization and internationalization, the number of taxpayers is increasing, the economic nature、organizational forms and type of operation of enterprise is making varied. These developing trends result in the exacerbation of the contradiction of tax management on t...学位:经济学硕士院系专业:经济学院财政系_财政学(含税收学)学号:1552008115186

    高效能反渗透/纳滤复合分离膜材料、其制备方法及用途

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    本发明公开了一种高效能反渗透/纳滤复合分离膜材料及其制备方法。该膜材料由纳米多孔材料与有机聚合物膜材料组成,并且纳米多孔材料嵌入在有机聚合物膜材料中。采用将纳米多孔材料预先自组装在由聚砜等超滤支撑材料构成的支撑层上面,随后通过聚合反应,将纳米多孔材料引入聚合物薄膜层中的方法,得到的复合分离膜材料能够促使H2O等小分子优先从有机聚合物膜层孔道和多孔纳米材料孔道快速透过,而无机盐、有机分子等大分子水合物不能透过,提高了膜渗透能力,同时增强了膜的化学稳定性和热稳定性,达到净化水资源的目的,特别适用于海水淡化、苦咸水淡化、生活污水净化及及食品或工业废水处理领域中

    氨基功能化金属有机骨架纳米材料设计合成与CO2捕获性能的研究

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    本文成功设计合成了一种新型的氨基功能化金属有机骨架 (metal-organic framework , MOF) 纳米材料,平均颗粒尺寸~50 nm(Fig. 1 Left)。研究结果表明,其Brunauer-Emmett-Teller比表面为1675 m2?g-1,且具有微孔和介孔的多级孔道结构(Fig. 1 Middle);气体吸附结果表明该材料具有优良的CO2捕获能力,在16 ℃,25 bar下,CO2的吸附性能达15 mmol g-1,并且具有较高的CO2/N2和CO2/CH4的理想选择系数(Fig. 1 Right);同时,该材料具有很好的热稳定性,在空气氛围下的热分解温度到达270 ℃以上。此外,由于该材料具有氨基功能基团和介孔结构,可以通过共价反应对该材料进行后处理修饰,从而获得具有所需要性能的新材料。因此,本研究在功能化金属有机骨架材料的设计合成、CO2捕获、分离领域具有重要的学术意义和实际应用价值

    一种富氮ZMOF类型金属有机骨架多孔材料的制备方法

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    本发明提供了一种新型富氮ZMOF类型金属有机骨架多孔材料的制备方法,该方法采用富氮唑类化合物作为反应用配体,与含有Zn2+的可溶锌盐在有机溶剂中发生溶剂热反应,得到富氮ZMOF类型金属有机骨架多孔材料,然后洗涤、抽真空以及高温活化,使有机溶剂从该富氮ZMOF类型金属有机骨架多孔材料中脱除。采用该方法制备得到的富氮ZMOF类型金属有机骨架多孔材料具有规则的晶体结构与均匀的孔径分布,较好的物理化学稳定性,以及优良的CO2选择吸附能力,因此在CO2捕获分离技术领域、有机分子的分离等技术领域具有很好的应用前景

    富氮金属有机骨架多孔材料的制备与气体吸附性能研究

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    高效CO2捕获材料开发是目前研究的热点之一1。本文采用富含氮元素的有机化合物为配体,与金属锌盐在有机溶剂中反应,获得一种淡黄色具有规则形貌的单晶。研究结果分析表明,该材料具有二维层状类沸石金属有机骨架(ZMOF)结构。并且具有很好的物理化学稳定性,如在水溶液中浸渍7天结构不发生改变,且在空气中热分解温度达到250 ℃度以上; BET比表面积达到340 m2/g,且具有均匀的孔径分布(~0.46nm)(Fig. 1 Left);气体吸附分析结果表明,该材料具有较高的CO2选择吸附能力(Fig.1 Right),在零CO2吸附量时其吸附焓达到~50 kJ/mol。我们推测这种较高的吸附焓可能是由于配体中的氮原子和功能基团(-NH2)与CO2具有较强的相互作用产生的。因此,富氮类材料在CO2捕获分离领域具有很好的应用前景

    Unknown parental group effects on harvest body weight in the base population of Litopenaeus vannamei

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    The whiteleg shrimp, Litopenaeus vannamei, is an introduced species in China; the genetic relationship and genetic background among introduced populations in China are not clear. To analyze the effects of these unknown parent groups (UPG) in the basic population of L. vannamei, three populations with different growth rates and survival rates were collected as founder populations and were established as the base population by the diallel- cross design. Four models, namely, the Best Linear Unbiased Prediction based on Pedigree (pBLUP), the pBLUP with genetic groups (pBLUP-GG), the Single Step Genomic BLUP (ssGBLUP), and the ssGBLUP with Metafounders (ssGBLUP-MF), were used to estimate variance components for the body weight of the base population. The effects of UPG on genetic parameters and breeding value across the four models were compared and analyzed by cross validation. The results showed that the highest additive genetic variance (22.58 4.39) and heritability (0.91 0.10) were obtained using the pBLUP model. The pBLUP-GG, ssGBLUP, and ssGBLUP-MF models decreased additive genetic variance by 16.25%-61.20% and heritability by 15.38%-46.15% compared with that of the pBLUP model. The 5-fold cross validation for genotyped and ungenotyped individuals indicated that the accuracy of the pBLUP model was the lowest (0.64-0.68) of all estimates, and the accuracies of the other three models increased by 7.25%-10.53% compared with that of the pBLUP model. The prediction bias of the other three models decreased by 2.83%-7.56% compared with that of the pBLUP model (1.06-1.19). In conclusion, the models considering UPG effects could avoid the overestimation of additive genetic variance components for body weight in the basic population of L. vannamei
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