交通运输业节能减排国际管理手段及启示

交通运输业的能源消费在许多国家中都占有较高比例,经济发展较快的国家更是如此。介绍了能源消费大国英国、美国、欧盟以及日本交通运输业节能减排采取的主要管理手段,包括健全的法律体系、节能技术创新、有效的税费政策等。借鉴其先进经验,为我国交通运输业节能减排管理工作提供启示。     

企业节能减排的监控系统研究

经济发展与节能减排是一个矛盾的统一体,如何在二者之间进行平衡,考验着中国人的智慧。通过行业分类选取恰当的节能减排指标、采用统计学的基本原理、应用质量控制的技术与方法,提出了节能减排的指标体系和监控方法,以期对节能减排实施动态监控,对我国现阶段的企业节能减排工作有着重要的参考价值。     

低功耗数字控制超长波发射与接收系统

针对管道、矿山和水下等特殊环境中的信息通讯与信号传输等问题,根据超长波(ELF Electromagnetic Wave)具有传播损耗小且相位稳定等特点,给出了超长波发射与接收系统的设计原理与实现过程.发射系统采用单片机控制,输出的信号经发射天线产生23 Hz超长波,接收系统对采集到的信号进行带通滤波及放大处理.工程实验表明,所设计的系统在锂电池供电状态下,具有发射功耗低(连续工作时间大于72 h)、发射功率大(传播距离大于10 m)、且对接收的信号处理快速可靠(动态时滞小于5 s)等优点.     

Predictive models for emission of hydrogen powered car using various artificial intelligent tools

This paper investigates the use of artificial intelligent models as virtual sensors to predict relevant emissions such as carbon dioxide, carbon monoxide, unburnt hydrocarbons and oxides of nitrogen for a hydrogen powered car. The virtual sensors are developed by means of application of various Artificial Intelligent (AI) models namely; AI software built at the University of Tasmania, back-propagation neural networks with Levenberg–Marquardt algorithm, and adaptive neuro-fuzzy inference systems. These predictions are based on the study of qualitative and quantitative effects of engine process parameters such as mass airflow, engine speed, air-to-fuel ratio, exhaust gas temperature and engine power on the harmful exhaust gas emissions. All AI models show good predictive capability in estimating the emissions. However, excellent accuracy is achieved when using back-propagation neural networks with Levenberg–Marquardt algorithm in estimating emissions for various hydrogen engine operating conditions with the predicted values less than 6% of percentage average root mean square error.     

P(VDF-TrFE) copolymer acoustic emission sensors

Acoustic emission (AE) sensors have been fabricated using polarized polyvinylidene fluoride/trifluoroethylene (P(VDF-TrFE)) piezoelectric copolymer films. The acoustic and electromechanical properties of the copolymers have been determined using the ultrasonic immersion technique and the resonance technique, respectively. The P(VDF-TrFE) AE sensors have been calibrated according to the ASTM standard and evaluated for potential application in the detection of AE in glass fiber reinforced polypropylene (GFPP). A ceramic AE sensor also has been fabricated using lead zirconate titanate (PZT) 7A piezoelectric ceramic and its sensitivity and performance are reported as well. The copolymer sensors do not show resonance peaks of the ceramic sensor and have adequate sensitivity. They can reproduce AE signals accurately without giving artifacts and have potential use in commercial AE systems.     

国内正电子发射断层(PET)现状和展望

介绍了国内外正电子发射断层(PET)发展概况。截止2003年3月，国内有22个PET中心(包括已建、在建和计划中)、4台PET单机。正电子药物(^18F—FDG)方面：除由IBA公司2台30MeV回旋加速器生产的^18F—FDG已进入临床研究外，PET中心的17台小型回旋加速器生产的FDG按医院制剂使用。2001年FDGPET检查约6700人次。本文讨论了我国PET发展中应注意的几个问题：如PET目前未进入医疗保险；PET中心数目的发展，宜在国家主管部门统一规划下并根据社会经济发展水平、医院功能定位及社会和公众的承受能力，合理布局、有限量地增加；加强基础科学与临床医学协作；重视人才培养及培训；建议核学会或核医学会下属设立PET学组或专门委员会，以作为各PET中心和主管部门联系的纽带与桥梁。     

Backscattered electron imaging of the undersurface of resin-embedded cells by field-emission scanning electron microscopy

In this study backscattered electron (BSE) imaging was used to display cellular structures stained with heavy metals within an unstained resin by atomic number contrast in successively deeper layers. Balb/c 3T3 fibroblasts were cultured on either 13-mm discs of plastic Thermanox, commercially pure titanium or steel. The cells were fixed, stained and embedded in resin and the disc removed. The resin block containing the cells was sputter coated and examined in a field-emission scanning electron microscope. The technique allowed for the direct visualization of the cell undersurface and immediately overlying areas of cytoplasm through the surrounding embedding resin, with good resolution and contrast to a significant depth of about 2 μm, without the requirement for cutting sections. The fixation protocol was optimized in order to increase heavy metal staining for maximal backscattered electron production. The operation of the microscope was optimized to maximize the number of backscattered electrons produced and to minimize the spot size. BSE images were collected over a wide range of accelerating voltages (keV), from low values to high values to give ‘sections' of information from increasing depths within the sample. At 3–4 keV only structures a very short distance into the material were observed, essentially the areas of cell attachment to the removed substrate. At higher accelerating voltages information on cell morphology, including in particular stress fibres and cell nuclei, where heavy metals were intensely bound became more evident. The technique allowed stepwise ‘sectional’ information to be acquired. The technique should be useful for studies on cell morphology, cycle and adhesion with greater resolution than can be obtained with any light-microscope-based system.     

气体分析法测定岩棉中甲醛释放量影响因素探讨

针对利用气体分析法测定岩棉中甲醛释放量的影响因素展开研究,从试验舱背景、洗瓶水的更换、硅胶有效性以及供气系统气密性等因素展开验证分析。结果表明,在洗瓶水甲醛含量未饱和的状态下,试验舱背景和洗瓶水的更换对试验结果没有明显影响,硅胶有效性和供气系统气密性对试验数据影响较大,其中供气系统气密性同时对硅胶有效性有显著影响,对试验结果影响最大。     

长三角地区农作物温室气体排放特征研究

为有效指导农业温室气体减排政策的制定,本研究分别采用CH4MOD模型和排放因子法估算了2018年长三角地区农作物甲烷(CH₄)和氧化亚氮(N₂O)排放,并分析其时空分布规律,最终建立了2018年长三角地区农作物1 km×1 km网格化温室气体排放清单.研究结果表明:长三角稻田CH₄排放因子为348.54 kg／hm²,农作物N₂O排放因子为0.95 kg／hm²,与前人研究结果具有一致性.长三角地区稻田CH₄排放为176.9万t(折合约3 714.9万t CO₂当量),最主要排放源为单季稻稻田;农作物N₂O排放为15114.9 t(折合约450.4万t CO₂当量),小麦是主要贡献源.CH₄和N₂O排放均主要来源于江苏省和安徽省,且集中在4—8月.建议加强对农业温室气体排放的管控,从源头上减少农田碳氮源的输入.