Design of the SD Card Driver for Car GPS Navigator Based on Windows CE

采用SD卡作为汽车导航仪系统的外扩存储器。根据SD卡的硬件特性,设计了CPU与SD卡的电路连接。并分析了Windows CE下流接口驱动的特点,以及SD卡驱动程序与中断的关系,提出了基于Windows CE下的SD卡驱动的实现方法。SD card is used as external memory in car navigator system in this article. The electrical connection between CPU and SD card is designed according to the speciality of SD card. And the features of stream interface drivers based on Windows CE and the relation between the interruption and the driver of SD card is analysed, then the implementation of the SD card driver is presented

上市公司股权融资偏好与经营绩效的实证分析

目前 ,我国上市公司在再融资方式的选择上存在着强烈的股权融资偏好。研究股权融资偏好行为与上市公司经营业绩之间的相关性不仅具有理论上的意义 ,而且对于上市公司、股东和经营者而言 ,都具有重要的实践意义。本文以实证的方法来分析这种相关性 ,结果认为上市公司过度的股权融资将造成其经营业绩的下

高管变更与盈余管理——基于应计项目操控与真实活动操控的实证研究

本文将应计项目操控和真实活动操控纳入分析框架,研究上市公司发生总经理变更后的盈余管理行为。理论分析表明,新任总经理在上任当年利用应计项目负向盈余管理可"一举多得",利用真实活动进行盈余管理却可能会"损公不利己";而在后续年度利用真实活动正向盈余管理虽会"损公"却可"利己"。以沪深A股上市公司2005-2010年数据为样本进行的实证检验结果显示,在总经理变更当年,上市公司存在利用应计项目调减利润的盈余管理行为,但不存在利用真实活动的盈余管理行为。在新任总经理上任后第一、二个完整会计年度,上市公司存在利用应计项目和真实活动调增利润的盈余管理行为。总经理变更当年,如果董事长也发生变更,则上市公司在变更当年利用应计项目调减利润的程度更大,在变更后第一、二个完整会计年度利用应计项目和真实活动调增利润的程度也显著更大

粉煤灰-矿粉-水泥三元胶凝材料对混凝土抗压强度的影响

为研究粉煤灰-矿粉-水泥三元胶凝材料对混凝土抗压强度的影响,测试混凝土标准养护3、7、14、28和56 d龄期的抗压强度,分析凝土抗压强度与胶凝材料各组分的关系。实验结果表明,混凝土抗压强度与粉煤灰-矿粉-水泥三元体系组分的掺量比例有密切关系。粉煤灰和矿粉双掺时,由于粒径不同会相互填充,从而产生超叠加效应,使掺加粉煤灰和矿粉的混凝土抗压强度得到明显改善。水泥、矿粉、水泥及粉煤灰的组合、粉煤灰和矿粉的组合对混凝土的抗压强度有增强作用,其中粉煤灰和矿粉的协同效应对混凝土抗压强度增强最为明显。随着龄期增加,粉煤灰和矿粉的协同效应对混凝土抗压强度的增强作用逐渐减弱,与28 d抗压强度相比,其对56 d抗压强度贡献降低了55.9%;粉煤灰及水泥-粉煤灰-矿粉的三元组合对混凝土抗压强度的影响逐渐降低,与28 d抗压强度相比,粉煤灰及水泥-粉煤灰-矿粉的三元组合对56 d抗压强度的降低效应分别减少了40.9%和67.3%。国家自然科学基金项目(51778551)福建省科技厅青年创新项目(2016J0514

An Empirical Study of Earnings Management Based on Real Activities Manipulation——Empirical Evidence from Chinese Listed Companies

以中国上市公司A股2002~2011年的数据为样本,对上市公司的真实盈余管理行为进行了实证研究。研究发现,微盈公司显著存在利用应计项目和真实活动进行正向盈余管理的现象,而在新会计准则实施后,微盈公司利用应计项目进行正向盈余管理的程度显著降低,但利用真实活动进行正向盈余管理的程度显著提高,说明新会计准则的实施促使微盈公司转而利用更加隐蔽的真实盈余管理进行利润操控。进一步研究发现,在控制了资产规模、资产回报率、年持有收益率、操控性应计利润及成长性等影响因素后,上市公司真实盈余管理的程度与其后期的业绩表现显著负相关,说明真实盈余管理行为会损害公司的长期价值。This paper empirically examine the real earnings management behavior of Chinese list companies with the data of Shanghai and Shenzhen A-share from 2002-2011.The results show that small profit companies manage earnings upwards significantly by accruals as well as real activities.Small profit companies use less accrual earning management but more real earnings management significantly after the promulgation of new accounting standards.It suggests that the promulgation of new accounting standards urge small profit companies switch to use more covert real activities to manage earnings.The further research shows that real earnings management is negative related to the subsequent operating performance of list companies after we control other influence factors.It suggests that real earnings management will harm companies' long term value.国家自然科学基金资助项目(70972111); 中央高校基本科研业务费专项资金资助项目(2011221035

A Method for Assessing the Sustainability of Design in Developing World Projects

Projects for the developing world usually find themselves at the bottom of an engineer’s priority list. There is often very little engineering effort placed on creating new products for the poorest people in the world. This trend is beginning to change now as people begin to recognize the potential for these projects. Engineers are beginning to try and solve some of the direst issues in the developing world and many are having positive impacts. However, the conditions needed to support these projects can only be maintained in the short term. There is now a need for greater sustainability. Sustainability has a wide variety of definitions in both business and engineering. These concepts are analyzed and synthesized to develop a broad meaning of sustainability in the developing world. This primarily stems from the “triple bottom line” concept of economic, social, and environmental sustainability. Using this model and several international standards, this thesis develops a metric for guiding and evaluating the sustainability of engineering projects. The metric contains qualitative questions that investigate the sustainability of a project. It is used to assess several existing projects in order to determine flaws. Specifically, three projects seeking to deliver eyeglasses are analyzed for weaknesses to help define a new design approach for achieving better results. Using the metric as a guiding tool, teams designed two pieces of optometry equipment: one to cut lenses for eyeglasses and the other to diagnose refractive error, or prescription. These designs are created and prototyped in the developed and developing worlds in order to determine general feasibility. Although there is a recognized need for eventual design iterations, the whole project is evaluated using the developed metric and compared to the existing projects. Overall, the success demonstrates the improvements made to the long-term sustainability of the project resulting from the use of the sustainability metric

Dynamic changes of phytoplankton ' s community structure in Beixi of Jiulongjiang River,Fujian Province of East China and related affecting factors

分别于2011年枯水期(2月)、丰水期(5月)和平水期(10月),系统调查研究了福建九龙江北溪浮游植物群落组成、丰度的分布特征及其与环境因子的关系.共鉴定浮游植物107种,隶属于7门64属.不同水文期浮游植物主要优势种类不同,枯水期为马索隐藻和梅尼小环藻,丰水期为四尾栅藻和四角十字藻,平水期则演替为微小平裂藻.不同水文期浮游植物丰度变化明显,其平均值依次为枯水期(154.77x104CEllS.l-1)>平水期(76.40x104CEllS.l-1)>丰水期(45.40x104CEllS.l-1).相关分析表明,枯水期和平水期浮游植物丰度与铵态氮(nH4+-n)呈显著正相关,丰水期浮游植物丰度与温度呈极显著正相关.典范对应分析(CCA)表明,水体温度是影响该水域浮游植物分布格局的重要因子,溶解态活性磷浓度也对浮游植物的分布有较大的影响.CCA排序图较好显示了浮游植物物种分布和环境因子之间的关系.An investigation was conducted on the phytoplankton's community composition,abundance,and their relations with environmental factors in Beixi of Jiulongjiang River,Fujian Province in February(dry season),May(wet season),and October(normal season),2011.A total of 107 phytoplankton species were identified,belonging to 64 genera and 7 phyla.The dominant species changed with seasons.Campylomonas marssoni and Cyclotella meneghiniana dominated in dry season,Scenedesmus quadricauda and Crucigenia tetrapedia dominated in wet season,and Merismopedia tenuissima dominated in normal season.The phytoplankton's abundance was the highest in dry season(averaged 154.77×104 cells·L-1),followed by in normal season(76.40×104 cells·L-1),and in wet season(45.40×104 cells·L-1).The abundance in dry and normal seasons was significantly positively correlated with water ammonium nitrogen concentration(P<0.05),while that in wet season was significantly positively correlated with water temperature(P<0.01).Canonical correspondence analysis(CCA) showed that water temperature was the most important factor affecting the phytoplankton's community structure,and dissolved phosphorous concentration also played important role for the community structure.The CCA ordination plots could well display the phytoplankton's community structure and its relationships with environmental factors.厦门市重大科技平台项目(3502Z20091005)资

The single pulse thermal effect mechanism of micro-EDM

为了解微能量单脉冲放电加工原理,文中从微细电火花单脉冲放电加工具有放电时间短,放电通道半径小,能量密度高等特点入手,从单脉冲热作用模型的放电通道半径和能量分配系数方面对当前电火花单脉冲蚀出模型进行改进。建立了时变放电通道的热作用模型,并验证了模型的正确性,提出了单脉冲热作用模型中能量分配到工件表面的百分比系数随着放电参数的变化而变化的规律,为微细电火花的广泛应用奠定基础。The single pulse micro electric discharge machining( micro-EDM) has the characteristics of short discharge time,small discharge channel radius,high energy density,etc. Considering these characteristics,the EDM single pulse erosion model is improved in plasma channel radius and energy distribution coefficient of the single pulse thermal effect model,to establish the thermal effect model of micro-EDM machining. The correctness of the model is verified by a reliable experimental method,which lays a foundation for the wide application of micro-EDM.贵州省教育厅基金项目(5392