煤体注水湿润半径预测的神经网络模型

合理的注水半径一直是煤体注水防尘技术中难以确定的参数。笔者基于对影响煤体注水半径因素的分析和神经网络理论的原理之上 ,设计网络模型为 3层 ,输入层为 7个节点 ,应用BP网络算法 ,建立了煤体注水湿润半径的预测模型 ,并对其参数进行了讨论。然后 ,用平顶山矿务局和水城矿务局 13个矿 19个回采工作面的统计资料对BP网络进行自适应学习 ,并取η =0 .9,α =0 .82 ,控制网络总误差E≤ 10 6。经过 2 12 34次迭代后 ,网络趋于稳定。用训练好的网络对平顶山矿务局的某矿的 3层煤的注水湿润半径进行预测 ,预测结果与实测值很接近。其误差分别为 0 .5 %,0 .6 %和 0 .7%。     

粉料无尘装车机工作原理及其在冶金厂矿的应用

介绍集装车与防尘统一于一体的无尘装车技术及具有设备本质安全化特点的无尘装车机在解决粉状物料装车作业时的扬尘问题,保护作业工人健康,维护厂区环境方面的重要优越性。     

浅谈我国逆反射材料现状及其发展趋势展望

随着逆反射材料的广泛应用 ,其带来的安全警示效果、产品质量、生产工艺、检测方法及规范管理等方面的问题被日趋重视 ,笔者通过对逆反射材料的基本构造及反光特性的分析 ,论述了其对人和物的安全防护作用 ,并对我国目前逆反射材料的应用领域、产品质量及检测设备、检测标准等方面的问题进行探讨和评述 ,根据国内外的发展趋势 ,对我国开发及发展逆反射材料产业提出了笔者观点 ,为政府决策提供科学依据     

带防腐层在役压力容器表面磁粉探伤灵敏度的试验研究

采用人工裂纹试样的方法 ,模拟压力容器涂刷油漆防腐层的状况进行磁粉探伤 ,得出了油漆防腐层厚度与裂纹检出灵敏度的定量关系 ;结合CVDA《压力容器缺陷评定》规范 ,探讨了试验方法对一般在役压力容器带有油漆的情况下 ,进行磁粉探伤检验的可行性。研究表明 :采用交流磁化法进行探伤 ,当漆层厚度大约小于2 5 0 μm时 ,灵敏度影响较小 ,同时亦表明不宜使用直流磁化方法。该结论对承受低应力工况条件下的压力容器安全质量检验和评估 ,具有重要参考价值     

Characterization of Dust Storms to Hong Kong in April 1998

In April 1998, two intense dust storms were generated in CentralAsia and transported eastward across East Asia (15 and 19 April). This article presents the chemical characterization ofHong Kong (HK) aerosols during the dust storms. During the 15 Aprildust storm, hourly respiratory suspended particles (RSP)(particle diameter smaller than 10 m) concentrationsmonitored at 7 sites in Hong Kong reached the peak valuessynchronously between 9 and 11 a.m. on 17 April, in which thehighest concentration was 267 g m^-3. Analysis ofthe RSP samples showed that concentrations of crustalelements (Ba, Ca, Cd, Cr, Fe, Mg, K⁺) and anthropogenicspecies (As, Ni, Pb, Zn, NH₄ ⁺, NO₃ ^-,SO₄ ^2- and total carbon) were substantiallyenhanced. Enhancement of these species was more than afactor of 2 to 14 relative to the non dust period. The totalcarbon content was high, at 59 g m^-3 (notincluding carbonate), and the enrichment factors of Asand Pb on 17 April were 122 and 117, respectively. Thisimplied that anthropogenic materials together with mineraldust were transported to HK from Mainland China. Based onmaterial balance calculations, mineral dust contributed41% to the observed RSP mass on 17 April, which was 2 times thatof the nondust sample (22%). From the 5-day backwardtrajectory analysis, this storm was transported directlyfrom Northwest China to HK. However, there was nocorresponding observation for the 19 April dust stormaerosol. Consequently, 15 April storm had stronger impact onHK's atmosphere than 19 April storm. Compared to the HK AirQuality Objective, 15 April dust storm did not cause seriousair pollution in HK.     

社区居民参与的激励因素——"周庄现象"的思考

从对“周庄现象”的思考提出了为实现旅游可持续发展而激励旅游地居民参与的两种因素——物质激励因素及非物质激励因素，分析了两种激励因素的运用与作用机理，认为激励手段的使用要根据旅游地的发展阶段有重点地确定，这样才能激发旅游地居民积极参与到旅游业的发展中去。     

最大剪切模量对土动力参数及地震反应的影响

最大剪切模量是影响土的动剪切模量比、阻尼比和土层地震反应的最重要参数之一。通常采用室内应变法来确定最大剪切模量，给出土的动剪切模量比和阻尼比，而采用现场剪切波速法求得的结果则很少见。研究了剪切波速法和应变法所确定的最大剪切模量对土动剪切模量比、阻尼比和土层地震反应的影响，推导了两种方法所确定的动剪切模量比和阻尼比之间的关系式。结果表明：最大动剪切模量对土的动剪切模量比、阻尼比和土层地震反应的影响很显著。     

湖南传统村落的防御性特征

防御性在中国传统村落的规划和建设中具有很高的研究价值。通过分析湖南传统村落在选址、空间形态、防火和建筑装饰等方面的防御性特征,指出传统村落的物质防御和精神防卫等防御理念具有明显的先进性与科学性。两个方面共同作用,所营造的传统村落的安全居住环境,是中国传统文化因素中的心理安全防御意识在具体环境中的物化体现,是中国传统哲学观念和生态环境观念的有机统一,指出传统村落的防御性在当今和谐社会宜居社区的规划和建设中的借鉴意义。     

Influence of the oxide content on the ignition energies of aluminium powders

Some results of determination of ignition energies for an aluminium powder with various oxide contents are presented. Common use of processes like high-speed cutting produce explosive dust clouds, so that we focused this study on hazard of metallic powders. An industrial aluminium powder has been used for this work. An original process, based on the principle of electrochemical anodisation, has been developed to increase, under control, the oxide coating of particles.

The sensitivity study to spark ignition was performed in an Hartmann explosion tube of 1.3L. The Langlie test method was applied to evaluate the energies leading to a probability of ignition of 50% (E₅₀) of the selected samples. The results confirm that the ignition energies increase with the oxide content of the powder.     

Book Reviews

Books reviewed:
Thomas Drabek, Disaster-induced Employee Evacuation
Hugh Brammer, Agricultural Disaster Management in Bangladesh
Boris Porfiriev, Disaster Planning and Emergency Management in Russia
Patrick Bracken and Celia Petty, eds, Rethinking the Trauma of War
R. Cohen and F. M. Deng, eds, The Forsaken People: Case Studies of the Internally Displaced
Tom Trier and Lars Funch Hansen, eds, Conflict and Forced Displacement in the Caucasus: Perspectives, Challenges and Responses