石英脉型钨矿山中深孔爆破震动规律分析与预测

针对石英脉型钨矿山细脉带型矿体中深孔爆破引起的爆破震动问题,进行采场爆破震动现场监测,探究震动速度、频率和能量随爆破炸药量、爆心距的变化趋势,并构建矿区爆破震动预测模型。研究结果表明,震动速度随着药量的增加或爆心距的减小而增大,主震频率随着药量的增加而降低,各频带能量与炸药量呈正相关,随爆心距的增加各频带能量减小,能量重心向低频转移,但信号的总能量却呈衰减之势。基于小波包技术的爆破震动预测在震动速度及频率范围两个方面较为准确,可满足工程计算和分析要求。     

灰色关联分析法在爆破震动监测中的应用

以国内某大型露天矿山15组爆破设计参数和爆破震动测量数据为依据,基于灰色关联分析法理论基础,计算得出爆破特征变量震动速度、震动主频、震动时间与爆破设计参数最大单段药量、总药量、爆心距之间的灰色关联度,成功预测各参数对爆破震动影响的主次关系。该矿山爆破影响震动速度和震动时间的主要因素为爆心距,影响震动主频的主要因素为最大单段药量。预测结果可为该矿山今后控制爆破震动提供理论依据。     

基于LS-DYNA的井下中深孔爆破地表震动强度模拟分析

为了研究微差爆破最大段药量和总药量对爆破震动的影响程度,在对某铀矿井下生产爆破进行爆破震动现场测试的基础上,采用LS-DYNA有限元软件分别以最大段药量和总药量作为集中药包进行数值模拟。分析结果表明,震动强度测试值介于最大段药量和总药量数值模拟值之间,最大段药量虽是影响微差爆破震动强度的重要因素,但非决定性因素,微差爆破震动强度与总药量有密切关系;井下生产爆破地表三维震动强度值中,水平径向值相对较小。     

寺坪试验厂球磨机传动基础拆除爆破实践

本文通过对金堆城钼业公司科研所寺坪试验厂车间内2号球磨机传动基础预裂切割拆除爆破实践与药量计算,引入了拆除爆破装药量的单位体积用药量系数 q 与最小抵抗线 W 及其关系。     

采空区对金属矿地下采场爆破地震效应的影响

采用速度传感器测定多采空区下中深孔爆破强制崩矿产生的地震效应,分析同段雷管起爆的药量、空区状况及介质所处位置与主要爆破自由面的空间关系,对介质峰值质点速度(PPV)产生的影响。研究结果表明:控制最大一段药量有利于维护采场和井下构筑物的稳定;采空区的存在,通过使爆破地震波绕射并耗散其能量,对远离爆破作业点介质的PPV值,起到不同程度的衰减作用;在其他条件基本相同的情况下,爆破作用使主要爆破自由面正后方介质产生的PPV值,明显大于自由面侧向介质产生的对应值。     

频率与拉速匹配关系对振痕的影响

分析了连铸机结晶器振动频率与拉速匹配关系对振痕间距的影响,探讨了使振痕间距较大的频率与拉速的匹配关系。     

一种计算双调谐交流电力滤波器参数的新方法

研究了一种获取双调谐交流电力滤波器电容和电感的方法,该方法根据设定的并联谐振电路的谐振频率、第一谐振频率和第二谐振频率,计算串联谐振电路的谐振频率,根据串联谐振电路的谐振频率、并联谐振电路的谐振频率、第一谐振频率和所述第二谐振频率,计算双调谐交流电力滤波器的第一电感、第一电容、第二电感和第二电容。实验证明,此方法不需要解多元或一元四次方程,只需要按一元二次根与系数的关系列出简明的表达式,就能迅速准确地计算出双调谐滤波器的各参数。     

金堆城露天采场北部边帮削坡减载爆破震动测试与分析

削坡减载是露天采场北部边帮综合治理的当务之急,在边坡上进行爆破作业产生震动,对边坡稳定有一定影响。通过对爆破震动测试,得出了边坡体上爆破震动的衰减规律,并对振速、频率、波延时间及加速度进行了分析,提出了较为合理的最大一段装药量及总装药量,为边坡爆破作业提供了一定的科学依据。     

岩体及充填体爆破振动速度衰减规律研究

巷道掘进爆破中,爆破振动是影响巷道稳定性和充填体稳定性的重要因素,频繁的爆破振动会对巷道围岩和充填体造成损伤,最终发生失稳破坏。通过建立爆破振动监测系统,改进爆破方案和监测位置研究岩体和充填体爆破振动速度衰减规律,得出岩体与充填体振动速度衰减规律的差异性,从而优化焦家金矿爆破药量。研究结果表明：距离爆源越近,爆破振动速度越大,而且会随着爆心距增加逐步衰减;最大振动速度出现在爆源附近,采场爆破对充填体的扰动破坏更大;距离爆炸点相等的充填体平均振动速度为0.223 cm/s,要大于岩体平均振动速度(0.087 cm/s)。根据焦家金矿岩体爆破振动速度传播特点,结合GB 6722—2023 《爆破振动安全规程》,得出了最大单段药量与安全距离的对应关系,提出了一种新的动力应力比法,不仅为优化凿岩爆破设计和爆破药量设计提供依据,而且为焦家金矿深层矿床安全高效开采提供可靠的保证。     

爆破振动对临近建筑物安全影响研究

为了研究某露天矿采场爆破作业对附近选厂内建筑安全性的影响,采用爆破振动监测系统在选厂内对两次不同最大单孔药量下的爆破作业进行监测。基于希尔伯特-黄变换(HHT)分析法,对两种情况下监测产生的振动信号数据进行分析研究,结果表明:两种情况下爆破振动信号的优势能量频带都在0~10 Hz,且随着最大单孔药量的增加,振动频率有往低频集中以及瞬时输入能量增大的趋势;结合《爆破安全规程》(GB6722—2014)中对于工业建筑安全允许标准,确定该选厂建筑最大安全允许振速为2.5 cm/s。     

Electromagnetic Environmental Impact of 500-kV Double-Circuit Transmission Lines

The strength of the power frequency electric intensity and magnetic field of the 500-kV double circuit transmission lines was calculated by using the equivalent charge method and the Ampere's Law,and the environmental impact factors of the fields were evaluated. By optimizing the phase sequence,the frequency electric intensity and magnetic field strength can be reduced. Within a distance of 25 m from the center of the transmission line,the power frequency electric intensity and magnetic field strength fall off sharply with the distance increase.Finally,the best phase sequence and the minimum ground clearance of the transmission lines were obtained to meet the requirements of the least impact on envionment.     

平面药包的最佳间距

在矿山剥离、场地平整以及建(构)筑物基坑开挖等露天爆破中,为了充分利用炸药能量将岩石松动或抛掷到一定区域,并确保底板满足一定平整度要求,按照爆破技术设计和工程质量要求,需要设计平面布药结构.本文通过在施工现场进行的大量小型模拟实验,对平面药包间、排距与爆破漏斗的开口面积、可见深度、爆岩的抛掷距离和堆积形态等关系进行了系统分析与研究.实验结果表明,当平面药包间、排距满足一定范围时,爆破漏斗的可见深度较小,而开口面积和抛掷距离最大,爆堆形态较好.平面布药结构存在一个有利于抛掷堆积的最佳间、排距.     

连铸小方坯远程热送热装过程温降计算模型

建立了多块小方坯温降分块计算模型,采用有限元法计算小方坏在远程热送热装过程中内部温度及表面温度变化,得到热送热装过程的温度变化规律,为提高热送温度及制定加热炉加热制度提供了依据。     

浅谈合理实施爆破降低采矿成本的几项措施

在矿山爆破作业中，适当提高一次炸药单耗，改善装药结构和合理使用炸药以及采用小抵抗线，大孔底距的孔网参烽，可以改善爆破质量，提高装矿效益，降低采矿总成本。     

微机控制高频开关直流电源的应用

文章介绍了直流电源的作用及组成,着重介绍了直流电源的充电系统。组成充电系统的主要设备：微机控制充电系统的高频开关充电机、电源系统监控装置的工作原理,以及该系统较好的稳压、稳流精度在实际应用中的良好效果。     

Different signaling pathway between sphingosine-1-phosphate and lysophosphatidic acid in Xenopus oocytes: functional coupling of the sphingosine-1-phosphate receptor to PLC-xbeta in Xenopus oocytes

We investigated the influence of the growth surface on the direction of Xenopus spinal neurite growth in the presence of a dc electric field of physiological magnitude. The direction of galvanotropism was determined by the substratum; neurites grew toward the negative electrode (cathode) on untreated Falcon tissue culture plastic or on laminin substrata, which are negatively charged, but neurites growing on polylysine, which is positively charged, turned toward the positive electrode (anode). Growth was oriented randomly on all substrata without an electric field. We tested the hypothesis that the charge of the growth surface was responsible for reversed galvanotropism on polylysine by growing neurons on tissue culture dishes with different net surface charges. Although neurites grew cathodally on both Plastek substrata, the frequency of anodal turning was greater on dishes with a net positive charge (Plastek C) than on those with a net negative charge (Plastek M). The charge of the growth surface therefore influenced the frequency of anodal galvanotropism but a reversal in surface charge was insufficient to reverse galvanotropism completely, possibly because of differences in the relative magnitude of the substratum charge densities. The influence of substratum adhesion on galvanotropism was considered by growing neurites on a range of polylysine concentrations. Growth cone to substratum adhesivity was measured using a blasting assay. Adhesivity and the frequency of anodal turning were graded over the range of polylysine concentrations (0 = 0.1 < 1 < 10 = 100 microg/ml). The direction of neurite growth in an electric field is therefore influenced by both substratum charge and growth cone-to-substratum adhesivity. These data are consistent with the idea that spatial or temporal variation in the expression of adhesion molecules in embryos may interact with naturally occurring electric fields to enhance growth cone pathfinding.     

On the kinetics of mechanical alloying

The kinetics of solid-state displacement reactions during mechanical alloying have been investigated. The effects of charge ratio and ball size on the progress of the reaction between CuO and Fe have been evaluated from measurements of ignition temperature, combustion time, and crystallite size. The reaction kinetics are shown to increase with charge ratio. This is rationalized in terms of the effect of charge ratio on the number of ball/particle collisions. Ball size influences reaction kinetics through both the particle collision frequency and collision energy.     

频分多址盲炮检测技术与系统在深孔爆破中的应用研究

针对深孔爆破中盲炮难以检测和识别的问题,开发了基于电磁波传播理论的深孔爆破盲炮频分多址检测技术与系统,并对检测系统的性能进行了试验研究。结果表明：在岩土体中传播的电磁信号发射频率越低其穿透能力越强,传播距离越远;在同等收发水平距离条件下,电磁信号幅值随着盲炮埋深的增加而减小,同时随着地下信号发生器发射频率的增大而减小;而且随着频率的增大,衰减趋势更明显。该盲炮检测系统良好的频响范围是2 012~5 025 Hz,对埋深≤40 m和收发水平距离≤30 m的深孔爆破盲炮,具有良好的检测识别能力。频分多址盲炮检测技术与系统可满足深孔爆破盲炮检测的要求。     

Development of the base of the cochlea: place code shift in the gerbil

Distortion product otoacoustic emission measurements were made at 1/12 octave intervals before and after the injection of furosemide in gerbils aged 15 days after birth to adult, in order to obtain estimates of cochlear amplifier gain as a function of stimulus frequency. The frequency at which the gains went sharply to zero, defined as the 'base cutoff frequency', increased from about 20 kHz to over 50 kHz during development. This increase provides further confirmation of the hypothesis that the place code changes during development in the basal part of the cochlea. If the measured base cutoff frequency is identified with the characteristic frequency at the basal end of the cochlea, as defined by electrophysiological measures, then these emission data can be used to generate a frequency-place map as a function of age. The derived place code shift is consistent with published electrophysiological measures, and can be used to extend these measures. Near the base cutoff frequency, the observed cochlear amplifier gain typically dropped sharply from a relative maximum to zero, over a distance of about a half octave. Specifically, this distance appeared to exhibit a curvilinear variation with age, reaching a maximum of 3/4 of an octave at 19-21 days. After transforming from frequency to place using the map derived from emissions, however, the distance between the extreme base and the place associated with the peak gain decreased monotonically from about 1.2 mm at age 15-19 days to 0.6 mm at maturity. This distance is assumed to be characteristic of the length of the active amplification zone for the cochlear amplifier in the base region. Over the same time period, there was approximately a doubling of the rate of amplification with distance from the base, so that the cochlear amplifier gain at the peak actually changed very little from 15 days to adult.