古建筑防雷设计的探讨

对于古建筑防雷,只有有效防止其受到直击雷的损害,才能最大程度保护古建筑,减少遭受雷击的可能性。结合实际工作经验,分析总结了古建筑防雷的基本原则,并结合某古建筑防雷设计案例,详细分析古建筑防雷综合设计,对加强古建筑的防雷工作有一定参考价值。     

黎平县古建筑防雷现状及解决对策探讨

通过对黎平县现有1 260座古建筑防雷现状进行防雷普查分析,发现到目前为止做到真正防雷安装的古建筑尚无一家,对保护我国文明遗物工作十分的不利。因此,针对黎平县古建筑在防雷方面存在的安全隐患提出相应的对策。     

古建筑雷电灾害及防雷技术研究综述

古建筑是宝贵的历史文化遗产,雷电灾害是威胁古建筑安全的主要因素之一。本文首先较完整地介绍了古建筑雷电灾害的总体研究进展,分别综述了古建筑构件的雷击破坏特征和机理,以及古建筑雷击起火灾害成因、方式和影响因素等方面研究现状,建议在雷击模拟试验基础上利用数值模拟分析方法研究雷击破坏基础性问题。分析了古建筑绝缘避雷与采用防雷装置接闪泄流两种方法,认为后者科学合理。通过归纳古建筑雷电防护技术研究进展、古建筑防雷新技术方法和装置,分析了古建筑防雷技术标准现状。最后,提出古建筑防雷有待深入研究的方向,包括开展古建筑雷击破坏机理、实用的防雷新技术、古建筑雷击选择性、雷击精细化监测预警等,特别是加强古建筑防雷新技术研究,尽量减小对古建筑原貌的影响,做好古建筑的防雷保护是非常关键和必要的。     

现代条件下的古建筑防雷

通过古建筑防雷工程的实践,结合历史文化名城北京的古建筑结构特点,分析了古建筑防雷的现状和存在的缺陷,并运用现代防雷新理念、新技术,以钟鼓楼、国子监、大钟寺古钟博物馆、中国协和医科大学等典型古建筑防雷实践为例,阐述了古建筑防雷工程中的接闪器、引下线、接地装置布设、雷电电磁感应、雷电静电感应、均压等电位及高大树木防雷等技术问题.针对古建筑引下线的布设距离不能满足国家现行规范的问题提出了通过加粗引下线的方法来解决的方案,并在实际工程中得到良好的使用效果.     

浅析景区古建筑、高大树木雷电防护要点

通过对古建筑物特点、古建筑已遭雷击的原因和现状等多角度分析.从古建筑的防雷类别的划分到古建筑及高大树木防雷工程设计、施工的工艺技术等多方面,阐述如何对古建筑进行防雷设计和施工,做到既保证其防雷效果,也不影响古建筑的外观与其周围环境协调一致.     

古建筑遭雷击原因及其防护措施

从雷电产生原理分析古建筑易遭雷击原因,防雷现存问题,提出了对古建筑防雷一些具体措施。     

藏式古建筑物的综合防雷设计——以文成公主庙为例

通过对传统藏式古建筑防雷技术的探究,进行藏式古建筑的雷电易损性分析。据此,进一步根据巴塘文成公主庙的现场勘查,在不破坏文物建筑的原貌下,进行外部防雷,最后为旅游参观所引入的低压线路、信号线路和电子设备进行内部防雷,形成一套完整体系的藏式古建筑防雷设计,从而得出结论藏式古建如何获得最大的艺术美观和最可靠的防雷保障。     

浅析加强文物古建筑综合防雷保护的重要性

通过对古建筑的重要性、火险特性、结构特点、防雷现状及其他因素分析,并结合近几十年来的一些案例,浅析了加强古建筑综合防雷的重要性。     

古建筑防雷设计探讨

通过对古建筑物防雷现状的调查,提出古建筑物的防雷设计应在确定雷电防护等级的基础上进行,古建筑物应采取防直击雷、侧击雷和防雷击电磁脉冲的措施,详细研究防雷装置的形式及其布置方式,防雷装置的安装应尽量做到保持古建筑物原貌和艺术特点。     

浅析加强文物古建筑综合防雷保护的重要性

通过对古建筑的重要性、火险特性、结构特点、防雷现状及其他因素分析，并结合近几十年来的一些案例，浅析了加强古建筑综合防雷的重要性。     

Rate constants for the reactions of the NO3 radical with HCOOH/HCOO− and CH3COOH/CH3COO− in aqueous solution between 278 and 328 K

The kinetics of the aqueous phase reactions of NO₃ radicals with HCOOH/HCOO^– and CH₃COOH/CH₃COO^– have been investigated using a laser photolysis/long-path laser absorption technique. NO₃ was produced via excimer laser photolysis of peroxodisulfate anions (S₂O ₈ ^2– ) at 351 nm followed by the reactions of sulfate radicals (SO ₄ ^– ) with excess nitrate. The time-resolved detection of NO₃ was achieved by long-path laser absorption at 632.8 nm. For the reactions of NO₃ with formic acid (1) and formate (2) rate coefficients ofk ₁=(3.3±1.0)×10⁵ l mol^–1 s^–1 andk ₂=(5.0±0.4)×10⁷ l mol^–1 s^–1 were found atT=298 K andI=0.19 mol/l. The following Arrhenius expressions were derived:k ₁(T)=(3.4±0.3)×10¹⁰ exp[–(3400±600)/T] l mol^–1 s^–1 andk ₂(T)=(8.2±0.8)×10¹⁰ exp[–(2200±700)/T] l mol^–1 s^–1. The rate coefficients for the reactions of NO₃ with acetic acid (3) and acetate (4) atT=298 K andI=0.19 mol/l were determined as:k ₃=(1.3±0.3)×10⁴ l mol^–1 s^–1 andk ₄=(2.3±0.4)×10⁶ l mol^–1 s^–1. The temperature dependences for these reactions are described by:k ₃(T)=(4.9±0.5)×10⁹ exp[–(3800±700)/T] l mol^–1 s^–1 andk ₄(T)=(1.0±0.2)×10¹² exp[–(3800±1200)/T] l mol^–1 s^–1. The differences in reactivity of the anions HCOO^– and CH₃COO^– compared to their corresponding acids HCOOH and CH₃COOH are explained by the higher reactivity of NO₃ in charge transfer processes compared to H atom abstraction. From a comparison of NO₃ reactions with various droplets constituents it is concluded that the reaction of NO₃ with HCOO^– may present a dominant loss reaction of NO₃ in atmospheric droplets.     

Kritische Bemerkung zur Frage der Temperatur-abhängigkeit der Ozonverteilung

Zusammenfassung A. undE. Vassy haben in der Frage der Temperatur-abhängigkeit des Ozongehalts der Atmosphäre aus der Gleichung loge _n –logJ _n logK(T _n ) geschlossen, daß auch die Gleichung loge _n logJ _n +logK(T _n ) gültig sei. Es wird hier nun gezeigt, daß die bei der ersten Gleichung erlaubten Vernachlässigungen bei der zweiten zu großen Fehlern führen können und daß daher von A. undE. Vassy kein Beweis für die Richtigkeit der Beziehunge=J.K(T) erbracht ist.

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Summary In the question of temperature dependence of ozone content of the atmosphere A. andE. Vassy have concluded from the equation loge _n –logJ _n logK(T _n ) that also the formula loge _n logJ _n +logK(T _n ) must be valid. In this paper it is proved that the neglections which may be admitted for the first equation, can conduct to great errors. Therefore A. andE. Vassy have not produced a proof for the correctness of the equatione=J.K(T).

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Résumé A. etE. Vassy en étuidant le problème de la teneur de l'ozone atmosphérique en relation avec la température ont admis que l'équation loge _n –logJ _n logK(T _n ) entraînait aussi la relation loge _n logJ _n +logK(T _n ). On montre ici que les simplifications admises pour la première équation conduisent pour l'application de la seconde à de fortes erreurs, et que par conséquent ces auteurs n'ont pas fourni de preuve de la justesse de la relatione=J.K(T).

     

Characteristics of ionic components in precipitation in Kitakyushu City,Japan

Precipitation samples were collected by filtrating bulk sampler in Kitakyushu City, Japan, from January 1988 to December 1990. Volume weighted annual mean of pH was 4.93, but the pH distribution indicated that most probable value lay in the range pH 6.0–6.4. Volume weighted annual mean concentrations of major ionic components were as follows; SO ₄ ^2– : 84.2, NO ₃ ^– : 28.1, Cl^–: 86.3, NH ₄ ⁺ : 45.5, Ca²⁺: 63.3, Mg²⁺: 27.0, K⁺: 3.4, Na⁺: 69.0 µ eq l^–1. The highest concentrations of these ionic components were observed in winter and the lowest occurred in the rainy season. The ratio of ex-SO ₄ ^2– /NO ₃ ^– exhibited the lowest ratio in summer, and the highest ratio in winter. Good correlations were obtained between Cl^– and Na⁺, ex-SO ₄ ²⁺ and ex-Ca²⁺, NO ₃ ^– and ex-Ca²⁺, and NH ₄ ⁺ and ex-SO ₄ ^2– , respectively. However, no correlation between Cl^– and Na⁺ with Ca²⁺ was observed. The relationship of H⁺ with (ex-SO ₄ ^2– + NO ₃ ^– ) - (ex-Ca²⁺ + NH ₄ ⁺ ) indicated positive correlation.     

The solubility and behaviour of acid gases in the marine aerosol

The following Henry's law constants (K _H/mol²kg^-2atm^-1) for HNO₃ and the hydrohalic acids have been evaluated from available partial pressure and other thermodynamic data from 0°–40°C, 1 atm total pressure: HNO ₃ , 40°C–5.85×10⁵; 30°C–1.50×10⁶; 25°C–2.45×10⁶; 20°C–4.04×10⁶; 10°C–1.15×10⁷; 0°C–3.41×10⁷. HF, 40°C–3.2; 30°C–6.6; 25°C–9.61; 20°C–14.0; 10°C–32.0; 0°C–76. HCl, 40°C–4.66×10⁵; 30°C–1.23×10⁶; 25°C–2.04×10⁶; 20°C–3.37×10⁶; 10°C–9.71×10⁶; 0°C–2.95×10⁷. HBr, 40°C–2.5×10⁸; 30°C–7.5×10⁸; 25°C–1.32×10⁹; 20°C–2.37×10⁹; 10°C–8.10×10⁹; 0°C–3.0×10¹⁰. HI, 40°C–5.2×10⁸; 30°C–1.5×10⁹; 25°C–2.5×10⁹; 20°C–4.5×10⁹; 10°C–1.5×10¹⁰; 0°C–5.0×10¹⁰. Simple equilibrium models suggest that HNO₃, CH₃SO₃H and other acids up to 10x less soluble than HCl displace it from marine seasalt aerosols. HF is displaced preferentially to HCl by dissolved acidity at all relative humidities greater than about 80%, and should be entirely depleted in aged marine aerosols.     

Regional effects of large-scale extreme wind events over orographically structured terrain

Summary ?Above orographically structured terrain considerable differences of the regional wind field may be identified during large-scale extreme wind events. So far, these regional differences could not be resolved by climate models. To determine the relationships between large-scale atmospheric conditions, the influence of orography, and the regional wind field, data measured in the upper Rhine valley within the framework of the REKLIP Regional Climate Project were analyzed and calculations were made using the KAMM mesoscale model. In the area of the upper Rhine valley, ratios of the wind velocity in the Rhine valley at 10 m above ground level, ν_val, and the large-scale flow velocity, ν_lar, are between ν_val/ν_lar ≈ 0.1 and ν_val/ν_lar ≈ 1. The ν_val/ν_lar ratio exhibits a strong dependence on thermal stratification, δ, and decreases from ν_val/ν_lar ≈ 1 at δ = 0 K m⁻¹ to ν_val/ν_lar ≈ 0.2 at δ = 0.0075 K m⁻¹. In areas, where the lateral mountainous border of the Rhine valley is interrupted, the ν_val/ν_lar ratio increases again with increasing stability or decreasing Froude number. This is obviously due to flow around the Black Forest under stable stratification. It is demonstrated by model calculations that a complex wind field develops in the Rhine valley at small Froude numbers (Fr < 1) irrespective of the direction of large-scale flow. The ν_val/ν_lar ratio is characterized by small values in the direct lee side (ν_val/ν_lar ≈ 0.2) and high values on the windward side of the lateral mountainous border of the Rhine valley (ν_val/ν_lar ≈ 0.8). Received October 22, 2001; revised June 18, 2002; accepted June 23, 2002