佛山市服装行业现状、问题与对策措施（下）

阐述了佛山市服装行业的现状,详细分析了其存在的主要问题和所具有的特色与优势,提出了提升佛山市服装行业科技竞争力的对策与措施.     

输配分离电力市场中含分布式发电的配电公司的购电模型

基于最优潮流建立了输配分离电力市场中,配电公司在日前电能市场的购电模型,在模型中考虑了分布式发电参与电能市场的情况,通过该模型可以得到配电公司在日前市场中分别从电力库和分布式发电商购买的电能比例以及可能的负荷中断。由于配电公司在购电时不仅考虑了购电费用最小化问题,还考虑了配网内的分布式发电对配电网损的影响,因此比较分析了不同最优目标对购电方案的影响。最后通过算例验证了上述模型的有效性,并分析了其特征。     

兼顾节能降耗的电网公司购电计划

合理制定购电计划有利于减少购电支出和降低网损,提出了一种兼顾网损的购电计划数学模型,以全网日购电费用和网损费用之和最小为目标函数,并满足各种机组技术约束和系统安全约束,进一步解耦成依次单时段模型,降低了解空间维数,提高了寻优效率.采用灾变遗传算法进行求解,仿真结果表明,相比传统购电计划,所提模型在显著节约购电成本的同时很好地降低了网损,符合当前阶段电网公司经济调度的需求.     

Chewing gum consumption in the United States among children,adolescents and adults

Data regarding chewing gum consumption habits and attitudes were collected for 963 children and adolescents (aged 6–14) and 3150 adolescents and adults (aged 13 years+) in the United States (U.S.) using a dedicated online food frequency questionnaire. A total of 79.6% of children/adolescents reported using chewing gum in the last 3 months, whereas 61.8% of adolescents/adults chewed gum in the previous 6 months. The mean and 90th percentile of consumption among children/adolescents aged 6–14 were 1.95 and 4.71 g day^?1, equivalent to 0.75 and 1.78 pieces per day, respectively. Stratification by gender and age brackets revealed that the consumption of chewing gum was more heavily reported in boys compared to girls. Among adolescents/adults aged 13 years and older, the mean and 90th percentile of consumption of chewing gum was estimated to be 2.98 and 7.67 g day^?1, or 1.05 and 3.00 pieces per day, respectively. Stratification by gender and by age brackets in this cohort did not reveal any marked patterns although it was noted that there was a decrease in the percent consuming with age (from 87.0 to 34.5%). The most commonly reported chew frequency among all ages was ‘two or three times a week’ (23.7 to 26.8%). The average and high-level estimates reported herein provide up-to-date estimates of chewing gum consumption in the U.S. Comparisons of the calculated intake values with those reported from the National Health and Nutrition Examination Survey dataset suggests that national nutrition surveys may result in an under-reporting of the percent consumers, but similar estimates for the daily intakes in g day^?1.     

网络食品交易安全法律问题

相对于传统的实体店交易,网络食品交易的环节及参与主体类型均较多,叠加网络交易的虚拟性、跨时空性、跨行政地域性等特点,导致网络食品交易的法律关系非常复杂,监管效果并不理想,侵犯消费者权益的现象时有发生。网络食品交易给政府监管带来了新课题、新挑战。笔者认为,网络食品交易安全治理不是政府监管机构所能独立完成的,而应当以政府监管为主导,强制第三方网络食品交易平台建立完善的网络食品交易信息数据库,并赋予其部分“准监管”权利;同时完善网络信用管理机制建设,对网络食品经营者进行信用分类监管,引导行业协会及消费者积极参与,方能达到比较理想的综合治理效果。     

网购食品安全协同治理体系探析

随着网络购物方式的不断普及,网购食品安全问题时有发生,传统的监管方式已难以适应网购食品安全监管的需要。本文在分析我国网购食品经营模式、网购食品安全监管难点及成因的基础上,从监管和监督两大体系出发,构建了网购食品安全协同治理体系,突出了“源头严控、过程严管、全程监督”的重要性,强调了多元参与、协同共治网购食品安全的必要性,拓展了网购食品安全治理的思路。     

基于在线预警探测系统的反应热失控判据研究

反应热失控是引发反应风险的主要因素。确保在线预警探测系统的可靠灵敏性,根据系统反应状态及时准确的预测反应热失控,是预防反应事故又一道防线;失控判据是发展在线预警探测系统的瓶颈。系统概述了在线预警探测系统反应热失控判据及其应用现状,包括限值检查判据、热平衡判据、基于模型的方法、散度判据和神经网络方法,分析比较了各种方法的优缺点,并对在线预警系统判据未来的发展给与展望。     

Size and power exchange optimization of a grid-connected diesel generator-photovoltaic-fuel cell hybrid energy system considering reliability,cost and renewability

In this paper, optimal size and power exchange of a grid-connected diesel generator-photovoltaic-fuel cell (diesel/PV/FC) hybrid energy system is investigated by multi-objective optimization for a community in Kerman, Iran. To optimally size hybrid system, number of system components (PV panels, diesel generators, electrolysers, FCs and hydrogen tanks) are considered as decision variables. In this paper, to optimize power exchange between the hybrid system and grid, two other decision variables are introduced: selling coefficient and purchase coefficient. Selling and purchase coefficients are defined to optimize the amount of electricity sold to the grid and the amount of electricity purchased from the grid, respectively. In order to optimally design the hybrid system, multi-objective optimization has been considered with respect to three objectives: levelized cost of energy (LCOE), loss of power supply probability (LPSP) and renewability. Based on simulation results, it can be drawn that when the hybrid system can sell/buy energy to/from the grid, (1) by decreasing non-renewable energy source usage, the value of LPSP increases, (2) by decrease of non-renewable energy usage, value of LCOE increases and (3) using FC system leads to increasing LCOE.     

基于改进的Prony算法在线辨识电力系统低频排振荡模式

基于传统的Prony算法对输入信号要求较高,同时对分析数据的噪声非常敏感,提出了一种改进的Prony算法,对在线获取的信号进行快速拟合,从而分析出信号的振幅、阻尼比、频率和相角等信息.改进的Prony算法的拟和精度在36节点的多机系统中进行验证,该算法输入信号是基于广域测量系统提供的各机组功角变量.仿真计算结果表明,该改进算法可实现低频振荡主导模式的在线辨识.     

分布式光纤XLPE电缆温度在线监测技术

电力电缆线路运行温度在线检测技术是当前及时发现电力电缆线路的局部过热点位置、检测运行线路的绝缘状态、计算导体载流量的首选技术措施。为此,基于光频域反射OFDR测温法研究了一种能实现长距离大范围的新型测温技术——分布式光纤测温技术,实现了电缆温度的实时测量,并探讨了使用测温技术进行绝缘在线监测的可能性。