基于Orion的A-GPS系统通信软件设计

GPS可提供全天候的精确位置与定时信息，但GPS卫星信号较弱，任何障碍物都会影响其信号的接收。本系统在国家GPS重点实验室支持下，通过在GPS导航芯片Orion中添加GPRS／GSM无线通信模块来实现GPS辅助定位。经过测试，本系统在障碍物附近可以明显提高GPS导航定位的速度，且大大提高了首次定位时间，率先在我国实现了A-GPS技术的产品级开发。     

币值低估下对外贸易对物价水平的影响

从货币数量方程出发,运用汇率理论与对外贸易理论,主要讨论了币值低估时,对外贸易对经济体内物价水平的影响.在外贸情况一定时,经济体内物价水平与币值低估程度正相关;当币值低估程度确定,进出口比例与外贸规模也会对经济体内的通胀大小产生影响,具体表现为:外贸顺差越大,通胀越严重;但贸易逆差时,仍然有可能出现通胀;而若要追求贸易平衡的目标,则外贸规模越大,通胀越严重.同时,一国的币值低估还通过对外贸易对他国的物价水平产生影响.     

Energetics of carbon nanotubes

We have investigated the energetics of carbon nanotubes. Calculations have been performed by using the empirical many-body potential energy function developed by Tersoff for carbon. Received: 30 March 1998 / Accepted: 28 July 1998     

The Ne II spectrum

Spectra of neon-filled hollow cathode discharge lamps were observed by means of high-resolution Fourier-transform spectroscopy (FTS) covering the region from vacuum ultraviolet to near infrared. By combining these new measurements with results of other FTS and grating spectroscopy observations, we compiled a complete list of approximately 1700 spectral lines of Ne II covering the range from 324 ? to 130000 ?. All known energy levels of Ne II were derived from this line list with improved accuracy. The newly optimized energy levels were used to derive a set of Ritz wavelength standards in the vacuum ultraviolet that are in good agreement with the previously used data. An improved classification of energy levels was made with the help of parametric calculations, and the existing controversy in the naming of strongly mixed levels was resolved. Electronic supplementary material Online Material     

公交服务治理模式的效益比较研究

公交服务的市场化改革需要选择合理的治理模式以应对产生的种种问题,各模式间的效益比较就成为选择的关键因素。在理论比较PPP模式和网络治理模式的基础上,本文以PPP模式为参照对象,假定公交服务参与主体平等的合作,从各主体的控制权分配、努力水平和产出效率构建公交服务总效益模型,并进行了模型的理论分析和数据模拟,结果表明:总效益与各方主体的努力水平、控制权和产出效率紧密相关,仅当政府和社会群体间的边际成本替代率在合理范围内时,网络治理模式的总效益大于PPP模式,当超出合理范围时会使前者小于后者。     

融入再审核的PPP项目动态绩效激励机制研究

基于政府角度探讨了针对PPP项目社会资本方的动态绩效激励机制,运用委托代理理论构建PPP项目绩效激励模型,包括静态绩效激励模型和融入再审核的两阶段动态绩效激励模型.同时,对社会资本方最优努力水平、政府效益最优化、再审核周期,以及绩效标准、奖罚系数、政府补贴等激励参数进行了分析,解释了政府的社会、经济、综合效益的影响因素,提出了优化建议.最后,通过案例展开数值分析,证明融入再审核的动态绩效激励机制能够实现综合效益的最大化.旨在为政府科学确定PPP项目运营阶段的绩效激励机制及再审核周期提供理论依据和决策支持.     

基于双重差分模型的参与PPP项目与企业技术创新关系研究

以2011～2018年沪深主板市场上市的企业作为研究对象,分析了上市企业参与PPP项目建设对企业自身技术创新水平的影响,并进一步探讨行业竞争对二者关系的调节效应。研究发现企业参与PPP项目建设总体会抑制企业技术创新投入,并且参与PPP项目程度越深,抑制作用越明显。二者的关系在科技型行业和传统型行业中存在异质,参与PPP项目有助于提高科技型企业技术创新,但是不利于提高传统型企业技术创新。行业竞争对PPP项目与企业技术创新的关系产生显著的调节作用,随着行业竞争加强,参与PPP项目与科技型企业技术创新的正相关越大,参与PPP项目与传统型企业技术创新的负相关越小。对此,企业家要有长远意识,坚持创新型发展,同时监管部门要充分利用行业竞争机制加快产业转型升级,破除垄断关系。     

Solid state structural aspects of electrochemically prepared poly (p -phenylene) thin films – crystalline order and spherulite morphology

The electrochemical polymerization of benzene via the microemulsion approach yields highly crystalline and anisotropic “spherulitic” polyparaphenylene (PPP) thin films. The crystalline order and the origin of spherulite morphology are discussed. Received: 29 July 1997 / Accepted: 27 October 1997     

乡村振兴战略下农村人居环境整治PPP模式合作行为演化博弈分析

农村人居环境整治是乡村振兴战略的重要内容,基于有限理性的演化博弈理论,构建了以地方政府、社会资本和农村居民为博弈主体的农村人居环境整治PPP模式合作行为演化博弈模型,运用Matlab软件分析了三方主体的初始意愿和政府规制对三方主体行为策略演化的影响。研究发现:(1)政府规制对农村人居环境整治PPP模式合作博弈系统演化的影响从大到小依次是:政府对社会资本的补贴资助、投机罚金、合作奖励和政府对农村居民的参与奖励。(2)与提高地方政府对社会资本的补贴资助力度和惩罚力度相比,提高地方政府的激励规制初始意愿更能促进农村人居环境整治PPP项目的顺利落地实施。(3)农村居民参与PPP项目的初始意愿的提升关键在于提高农村居民参与收益。最后,为促进PPP模式在农村环境治理领域的应用与发展和推动农村人居环境整治的可持续改善提出相应建议。     

A new method to avoid PPP in data evaluation

The Peelle Pertinent Puzzle (PPP) has been studied systematically. The results obtained by using several proposed methods to deal with a sample of {}^6Li(n, t) are compared with each other. The cause of PPP occurrence has been found. A new method to avoid PPP is introduced, whose main idea is ‘to selectively make suitable correction for systematic error according to the relative extent of discrepancy'. The method is able to produce the best result and should be used to avoid the PPP at first.