Dietary exposure to organochlorine pesticide residues of the Hong Kong adult population from a total diet study

Dietary exposure of the Hong Kong adult population to organochlorine pesticide (OCP) residues was estimated using a total diet study (TDS) approach. OCPs listed under the Stockholm Convention as persistent organic pollutants (POPs) including, aldrin, dieldrin, chlordane, chlordecone, dichlorodiphenyltricholroethane (DDT), endosulfan, endrin, heptachlor, hexachlorobenzene (HCB), α-hexachlorocyclohexanes (HCH), β-HCH, lindane, mirex, pentachlorobenzene and toxaphene, were studied. Out of 600 composite samples, 55% contained one or more OCP residues at detectable levels. The most commonly detected OCP was DDT (32% of all composite samples), followed by HCB (30%) and endosulfan (22%). The lower- and upper-bound mean exposure estimates of OCP residues ranged from 0% to 0.5% and were 0.1–8.4% of their respective health-based guidance values (HBGVs). The lower- and upper-bound 95th percentile exposure estimates ranged from 0% to 1.2% and were 0.1–13.6% of their respective HBGVs. This indicated that dietary exposures to the OCP residues analysed would be unlikely to pose unacceptable health risks to Hong Kong adults.     

Improved delay-range-dependent stability analysis of a time-delay system with norm bounded uncertainty

This paper presents improved robust delay-range-dependent stability analysis of an uncertain linear time-delay system following two different existing approaches – (i) non-delay partitioning (NDP) and (ii) delay partitioning (DP). The derived criterion (for both the approaches) proposes judicious use of integral inequality to approximate the uncertain limits of integration arising out of the time-derivative of Lyapunov–Krasovskii (LK) functionals to obtain less conservative results. Further, the present work compares both the approaches in terms of relative merits as well as highlights tradeoff for achieving higher delay bound and (or) reducing number of decision variables without losing conservatism in delay bound results. The analysis and discussion presented in the paper are validated by considering relevant numerical examples.     

小孔径蝴蝶型光电导天线太赫兹辐射源的研究

研究了5种小孔径光电导天线的太赫兹发射特性,并且对它们所发射的太赫兹波进行了对比,为研制高效率的太赫兹波发射源提供了参考依据。利用太赫兹时域光谱技术测量了光电导天线发射的太赫兹（THz）脉冲,得到了时域发射光谱,并通过快速傅里叶变换得到相应的频域光谱。结果表明,太赫兹信号强度随偏置电压的增大而增强;随着泵浦激光功率的增大而增强并出现饱和现象。偏置电压与泵浦激光功率相同时,我们对比5种光电导天线产生的太赫兹信号,从中找到了一种发射效率较高的小孔径光电导天线,并且研究了电极形状、电极间距对光电导天线发射效率的     

通过TDS3032B的LAN接口实现信号测量

本文针对如何通过TDS3032B示波器的LAN接口实现网络测量问题,介绍了其LAN接口DHCP、仪器名、用户口令、仪器IP地址、域名、DNSIP地址、网关IP地址、子网模板、Http接口参数的含义、设置方法及利用VISA函数在LabVIEW8。5环境下,实现脉冲参数测量程序设计。该方法利用了仪器本身资源,节约了购买TDS3GV模块几千元的经费,达到了通过GPIB控制示波器的同样效果,读者可以直接利用程序中的原代码,避免程序设计中繁琐调试过程,对程序设计者具有很高参考借鉴价值。     

Dietary Manganese Exposure in the Adult Population in Germany—What Does it Mean in Relation to Health Risks?

Manganese is both an essential nutrient and a potential neurotoxicant. Therefore, the question arises whether the dietary manganese intake in the German population is on the low or high side. Results from a pilot total diet study in Germany presented here reveal that the average dietary manganese intake in the general population in Germany aged 14–80 years is about 2.8 mg day^?1 for a person of 70 kg body weight. This exposure level is within the intake range of 2–5 mg per person and day as recommended by the societies for nutrition in Germany, Austria, and Switzerland. No information on the dietary exposure of children in Germany can be provided so far. Although reliable information on health effects related to oral manganese exposure is limited, there is no indication from the literature that these dietary intake levels are associated with adverse health effects either by manganese deficiency or excess. However, there is limited evidence that manganese taken up as a highly bioavailable bolus, for example, uptake via drinking water or food supplements, could pose a potential risk to human health—particularly in certain subpopulations—when certain intake amounts, which are currently not well defined, are exceeded.     

西山煤田古交矿区煤层气藏水文地质特征及其控气作用

煤层气藏的水文地质条件是控制煤层气运移、散失、分布和富集的重要因素之一。以西山煤田古交矿区为研究对象,分析产出水离子浓度、水质水型、矿化度和煤层含气量分布特征,结合地下水动力场分布特征,划分区域水文地质单元,并讨论不同单元内含气量分布特征及地质控制机理。结果表明:(1)该区煤层气井产出水离子以Na~+,HCO_3~-为主,水型主要为NaHCO_3型,该区煤层气井产出水矿化度介于632~2 512 mg/L,属于淡水-微咸水;(2)根据折算水位和矿化度分布特征将矿区划分为补给径流区、滞留区以及过渡地带的弱径流区3种水文地质单元,滞留区含气量最高,弱径流区次之;(3)古交矿区煤层气的富集成藏受构造、水文地质条件双重控制,在屯兰中部形成单斜-水力封堵型煤层气藏,为全区煤层气最为富集区,东曲断层比较发育,形成地垒-水力封堵型煤层气藏,为煤层气较为富集区。     

Photoelectron spectroscopy and secondary ion mass spectrometry characterization of diamond-like carbon films

Photoelectron spectroscopy at different photon energies was used to optimize the photoexcitation cross section for valence band study of diamond-like hydrogenated carbon films. The electronic states of diamond-like carbon (DLC) were studied by synchrotron radiation photoelectron spectroscopy and ultraviolet photoelectron spectroscopy. The valence band spectra measured at different excitation energies show the gradual emergence of the p-π band in relation to the sample annealing and ion bombardment amorphization. The p-π band of the annealed DLC was characterized by localized p_z states whilst the formation of the amorphous carbon surface was accompanied by appearance of the delocalized p_z states in the gap. Secondary ion mass spectrometry and thermal desorption spectroscopy showed that sample annealing was accompanied by hydrogen content decrease.     

通信电缆配线架地理模型设计与实现

提出通信电缆配线架地理模型,设计了一系列简捷、有效的配线架维护算法,并在MapInfo平台通过MapBasic编程已完全实现,较好地解决了电信资源海量数据处理问题,为实现对用户线路网管线资源的高效、可视化管理提供了一条有效途径．     

TDS法与ATH法铁水脱硫技术的特点

论述了大型炼钢厂铁水脱硫的必要性与发展，对两种主要的混铁车顶喷脱硫技术进行了比较，介绍了武钢三炼钢厂铁水脱硫的形式及其技术特点。