集中药包和分集药包爆破效果的试验研究

在现场进行了集中药包与分集药包硐室爆破的大量模拟试验。文中对两种药包产生的爆破漏斗和抛掷堆积效果进行了分析 ,并就两种药包产生的爆破漏斗的上、下破裂线和深度以及最远抛距等参数的试验值与计算值进行了对比。同时 ,对分集药包最佳间距进行了研究。试验得出的结论是 :在定向爆破筑坝中 ,可以采用分集药包改善抛掷堆积效果 ;在按经验公式计算的药量不变的前提下 ,存在一个有利于抛掷堆积的分集药包“最佳间距”。     

岙山基地的硐室大爆破

通过岙山基地的爆破工程,介绍了条形分集药包硐室大爆破的设计要点,根据工程要求选择爆破方案,依据地质条件选择爆破参数,应用先进理论进行爆破设计,采取有效技术措施确保地面建筑安全.设计中,对分集药包的计算、空腔比的选择、爆破地震和飞石的控制等问题作了研究.     

条形药包定义的探讨

通过理论推导，试验研究，给出了条形药包装药长度必须满足的条件，并利用试验证实了它的正确性。通过对条形药包整个爆破过程中爆破作用特性的分析，说明了条形药包在爆破中表现出的优点。     

布药结构与抛掷堆积规律研究

定向爆破设计的核心内容是抛掷堆积计算,而抛掷堆积规律主要决定于布药结构.通过对通常采用的集中药包、条形药包和分集药包3种布药结构进行系统的爆破试验研究,以总结布药结构与抛掷堆积规律的关系,从而为定向爆破设计提供参考.     

分集药包在爆破封堵非法盗采煤窑中的应用

为彻底封堵非法盗采煤窑,采用分集药包爆破的方法,来破坏非法盗采煤窑的内部结构。盗采煤窑深度30～40 m不等,依据类似工程经验,每个煤窑需要炸毁的长度约为20 m;采用分集装药结构,将装药的药包均匀分布于巷道内,每个药包间距4 m,参考硐室爆破计算,获得分集药包位置和爆破参数。为了保证爆破安全及封堵效果,在硐内部支巷用编织袋装土后进行填塞,填塞长度不少于8m。爆后检查结果为煤窑顶板围岩坍塌,沿巷道形成爆破漏斗,达到封堵目的。     

分集药包在爆破封堵非法盗采煤窑中的应用

为彻底封堵非法盗采煤窑,采用分集药包爆破的方法,来破坏非法盗采煤窑的内部结构。盗采煤窑深度30～40 m不等,依据类似工程经验,每个煤窑需要炸毁的长度约为20 m;采用分集装药结构,将装药的药包均匀分布于巷道内,每个药包间距4 m,参考硐室爆破计算,获得分集药包位置和爆破参数。为了保证爆破安全及封堵效果,在硐内部支巷用编织袋装土后进行填塞,填塞长度不少于8m。爆后检查结果为煤窑顶板围岩坍塌,沿巷道形成爆破漏斗,达到封堵目的。     

分集药包在硐室爆破中的应用

分集药包可用于减小爆破震动 ,增强堵塞效果 ,减小压碎圈半径 ,改善破碎效果 ,以及处理一些特殊的地形与地质构造。但是 ,应注意合理选择微差时间间隔、爆破作用指数和药包间距 ,并且应加强堵塞。     

分集药包在硐室爆破中的应用

分集药包可用于减小爆破震动 ,增强堵塞效果 ,减小压碎圈半径 ,改善破碎效果 ,以及处理一些特殊的地形与地质构造。但是 ,应注意合理选择微差时间间隔、爆破作用指数和药包间距 ,并且应加强堵塞。     

复杂环境条件下的分集药包硐室爆破

通过浙江省舟山市岙山基地的硐室爆破工程,介绍了条形分集装药硐室爆破设计的各环节.根据工程要求选择爆破方案,依据地质条件选择爆破参数,引入先进理论进行爆破设计,采取有效技术措施确保地面建筑安全.对条形分集药包的计算、爆破空腔效应、爆破地震效应等方面作了探索和研究.     

抛掷爆破最优间距探讨

1 引言在大型渠道开挖、爆破采石以及定向爆破工程中,一般都采用多药包联合爆破,而此时药包间距是影响工程经济性和爆破效果的主要参数.当药包间距过大时,爆破后留有残埂,爆破方量减少,开挖面不平整;当药包间距过小时,装药量增加,爆破不经济.从抛掷爆破的特点讲,在爆破作用指数n、最小抵抗线w一定的情况下,多药包联合爆破的最优药包间距为药包爆破时使介质达到最大抛掷量所对应的间距.本文通过对药包联合爆破时抛掷方量分析,对等量集中药包、等量对称多药包抛掷爆破最优间距进行讨     

隧洞开挖光面爆破装药结构的改进与应用

为了解决乌干达卡鲁玛尾水隧洞光面爆破施工中,无专用光爆细药卷(φ20²2mm),且竹片难于买到,无法绑扎光爆药串等问题,在8#、9#、10#支洞及主洞开挖爆破施工中做了一系列光面爆破装药结构改进实验。采用(φ2522mm),且竹片难于买到,无法绑扎光爆药串等问题,在8#、9#、10#支洞及主洞开挖爆破施工中做了一系列光面爆破装药结构改进实验。采用(φ25³2mm)常规药卷,在其未与导爆索绑扎的条件下,导爆索成功起爆了光爆孔内按设计线装药密度装入的间隔装药,且取得了理想的光爆效果。实验及应用情况表明:在φ42mm光爆孔内,导爆索与一定间距(>50cm)的间隔装药在孔内自由分布、未绑扎的条件下,导爆索完全能够起爆孔内的间隔装药,这就简化了传统的光爆药串加工工艺,改变了隧洞开挖中传统的光爆孔内装药结构。     

Multiresidue method for pesticides in drinking water using a graphitized carbon black cartridge extraction and liquid chromatographic analysis

A general liquid-solid extraction procedure for the isolation of pesticides from groundwater and drinking water for high-performance liquid chromatography (HPLC) is presented. This simple and rapid procedure involved passing a 2-L sample through a 250-mg graphitized carbon black (Carbopack B) cartridge at a flow rate of 150-160 mL/min. By taking advantage of the presence of positively charged active centers on the Carbopack B surface, a stepwise elution system allowed the complete separation of base-neutral pesticides from acidic ones. After partial solvent removal, the components in the two fractions were separated and quantified by gradient elution, reversed-phase HPLC with ultraviolet (UV) detection. The performance of the Carbopack cartridge was compared with that of a 500-mg C-18 bonded silica cartridge. With the Carbopack cartridge, the grand mean measurement accuracy of the 35 pesticides considered was 95%. With the C-18 cartridge, the grand mean measurement accuracy of the analytes was 76%. Compared to the C-18 cartridge, additional advantages of using a Carbopack cartridge are that the extraction procedure is about 7 times shorter, no pH adjustment of the environmental sample is necessary for trapping acidic compounds, and one cartridge instead of two suffices to extract base-neutral and acidic pesticides, making the Carbopack cartridge more adaptable than the C-18 one for field use. The detection limits by this method of all the pesticides considered were between 0.003 and 0.07 micrograms/L.     

Peptide electroextraction for direct coupling of in-gel digests with capillary LC-MS/MS for protein identification and sequencing

An electrophoretic method has been developed for the extraction of peptides following in-gel digests of SDS-PAGE separated proteins. During electroextraction, the peptides are trapped on a strong cation-exchange microcartridge, before analysis by capillary LC--ESI-tandem mass spectrometry. The spectra obtained by tandem mass spectrometry are searched directly against a protein database for identification of the protein from which the peptide originated. By minimizing surface exposure of the peptides during electroextraction, a reduction of the detection limits for protein identification is realized. The performance of the peptide electroextraction was compared directly with the standard extraction method for in-gel protein digests, using a standard dilution series of phosphorylase B and carbonic anhydrase, separated by SDS-PAGE. The lowest gel loading in which phosphorylase B was identified using the standard extraction method was 2.5 ng or 25 fmol, and the lowest gel loading in which phosphorylase B was identified using electroextraction was 1.25 ng or 12.5 fmol. The design of the microextraction cartridge allows for direct interfacing with capillary LC, which is crucial for maintaining low detection limits. Furthermore, this method can be used for high-throughput proteomics since it can be easily multiplexed and requires only voltage control and low pressures (approximately 15 psi) for operation. We believe that peptide electroextraction is a significant advance for identification of proteins separated by one-dimensional or two-dimensional gel electrophoresis, as it can be easily automated and requires less protein than conventional methods.     

条形药包爆破震动场的试验研究

通过时条形药包周围实测爆破震动数据采用数值计算方法进行处理，作出了条形药包周围的爆破震动场，使我们对条形药包的爆破地震效应有了全面的认识，从而在实际工程爆破中能够有针对性地进行安全防护。分析研究认为：条形药包周围的震动场由一系列同心椭圆形等震线组成。在爆破近区由于位置因素的影响，等震线的长轴与药包轴线重合；在远区的震动主要受波动干涉作用的影响，致使长轴与药包轴线垂直，因此不能采用集中药包的计算方法。     

条形药包爆破震动场的试验研究

通过时条形药包周围实测爆破震动数据采用数值计算方法进行处理，作出了条形药包周围的爆破震动场，使我们对条形药包的爆破地震效应有了全面的认识，从而在实际工程爆破中能够有针对性地进行安全防护。分析研究认为：条形药包周围的震动场由一系列同心椭圆形等震线组成。在爆破近区由于位置因素的影响，等震线的长轴与药包轴线重合；在远区的震动主要受波动干涉作用的影响，致使长轴与药包轴线垂直，因此不能采用集中药包的计算方法。     

Simultaneous determination of ozone and carbonyls using trans-1,2-bis(4-pyridyl)ethylene as an ozone scrubber for 2,4-dinitrophenylhydrazine-impregnated silica cartridge

A new method for the simultaneous determination of ozone and carbonyls in air using a two-bed cartridge system has been developed. Each bed consists of reagent-impregnated silica particles. The first contains trans-1,2-bis-(4-pyridyl) ethylene (BPE) while the second contains 2,4-dinitrophenylhydrazine (DNPH). Air samples are drawn through the cartridge first through the BPE and then through the DNPH. Ozone in the air sample is trapped in the first bed by the BPE-coated silica particles and produce pyridine-4-aldehyde. Airborne carbonyls pass unimpeded thorough the BPE and are trapped in the second bed by the DNPH-coated silica particles. They produce carbonyl 2,4-DNPhydrazones. DNPH and carbonyl 2,4-DNPhydrazones are not influenced by ozone because of effective trapping by the BPE. Extraction is performed in the direction reverse to air sampling. When solvent is eluted through the BEP/DNPH cartridge, excess DNPH is washed into the BPE bed where it reacted with pyridine-4-aldehyde and forms the corresponding hydrazone derivative. All of the hydrazones derived from airborne carbonyls and pyridine-4-aldehyde (derived from ozone) are completely separated and measured using high-performance liquid chromatography. An Ascentis RP-Amide column is used, and the mobile phase is 40% aqueous acetonitrile containing 2 mmol/L ammonium acetate. The use of a BPE/DNPH cartridge has made possible the simultaneous determination of ozone and carbonyls. A separate ozone scrubber is not necessary with the BPE/DNPH cartridge because the BPE portion of the sampler serves this function.     

Integration of dialysis membranes into a poly(dimethylsiloxane) microfluidic chip for isoelectric focusing of proteins using whole-channel imaging detection

A poly(dimethylsiloxane) microfluidic chip-based cartridge is developed and reported here for protein analysis using isoelectic focusing (IEF)-whole-channel imaging detection (WCID) technology. In this design, commercial dialysis membranes are integrated to separate electrolytes and samples and to reduce undesired pressure-driven flow. Fused-silica capillaries are also incorporated in this design for sample injection and channel surface preconditioning. This structure is equivalent to that of a commercial fused-silica capillary-based cartridge for adapting to an IEF analyzer (iCE280 analyzer) to perform IEF-WCID. The successful integration of dialysis membranes into a microfluidic chip significantly improves IEF repeatability by eliminating undesired pressure-driven hydrodynamics and also makes sample injection much easier than that using the first-generation chip as reported recently. In this study, two microfluidic chips with a 100-microm-high, 100-microm-wide and a 200-microm-high, 50-microm-wide microchannel, respectively, were applied for qualitative and quantitative analysis of proteins. The mixture containing six pI markers with a pH range of 3-10 was successfully separated using IEF-WCID. The pH gradient exhibited a good linearity by plotting the pI value versus peak position, and the correlation coefficient reached 0.9994 and 0.9995 separately for the two chips. The separation of more complicated human hemoglobin control sample containing HbA, HbF, HbS, and HbC was also achieved. Additionally, for the quantitative analysis, a good linearity of IEF peak value versus myoglobin concentration in the range of 20-100 microg/mL was obtained.     

Size exclusion chromatography of microliter volumes for on-line use in low-pressure microfluidic systems

We have developed a new cartridge format for on-line size exclusion processing in low-pressure, portable microfluidic devices. The described system allows size exclusion chromatography of microliter volumes (termed muL-SEC) to be performed with ready integration in complex protocols for continuous-flow sample processing and analysis. The refillable cartridge format was employed for the preparation of Bacillus subtilus spores lysed in the presence of a strong reducing agent. While the reducing agent is known to interfere with subsequent fluorescent labeling of the solubilized proteins, the described continuous-flow size exclusion processing allowed complete isolation of interferences from a 10-muL sample in 70 s. Following efficient labeling, the protein sample was injected and separated on-chip using gel electrophoresis. To increase the resolution, speed, and sample capacity of buffer exchange under low-pressure operation (40 psi), parameters such as the size exclusion resin, load volumes, flow rates, buffer composition, and cartridge geometry were optimized and are presented here. The muL-SEC analysis is compatible with automated sample preparation for microfluidic systems and has resulted in significantly increased analysis speed and throughput over benchtop methods. The presented technique has the potential to improve capabilities such as buffer exchange, size fractionation, and high-abundance protein removal-steps that are frequently required prior to on-chip, point-of-care, and mass spectrometric analyses.     

Extraction and isolation of triazine herbicides from water and vegetables by a double trap tandem system

The ability of a two-trap tandem system, one containing a nonspecific adsorbing material, such as graphitized carbon black (Carbopack B), and the other one filled with a sulfonic acid type silica-based cation exchanger (SCX), in extracting and isolating basic compounds from real matrices was evaluated by applying this device to the determination of triazine residues in water and vegetables. After percolation through the Carbopack column (extraction cartridge) of water samples or suitably prepared vegetable extracts, the two traps were connected in series, a methylene chloride-methanol mixture was allowed to flow along them, and triazines displaced from the extraction cartridge were selectively reabsorbed via salt formation on the strong acid exchanger column (isolation cartridge). After the column was washed, the analytes were removed from the isolation cartridge by 0.7 mL of aqueous methanol containing 70 mmol/L KCl. After the internal standard was added, the final solution was directly injected into the "high-performance" liquid chromatographic apparatus, which was operated isocratically in the reverse-phase mode with UV detection at 220 nm. The analytical recoveries of eight triazines from the two matrices considered ranged between 95% and 100%. The limits of sensitivity of this method for triazines were set at 10 ng/g of vegetable material and 10 ng/L of water by sampling 100 mL of it.     

Reagent-loaded cartridges for valveless and automated fluid delivery in microfluidic devices

An important problem in the life sciences and in health care is simple and rapid detection of biomarkers. Although microfluidic devices are potentially useful in addressing this problem, current techniques for automating fluid delivery--which include valves and electroosmosis--require sophisticated microfabrication of the chip, bulky instrumentation, or both. In this paper, we describe a simple and reliable technique for storing and delivering a sequence of reagents to a microfluidic device. The technique is low-cost, requires minimal user intervention, and can be performed in resource-poor settings (e.g., outside of a laboratory) in the absence of electricity and computer-controlled equipment. In this method, cartridges made of commercially available tubing are filled by sequentially injecting plugs of reagents separated by air spacers. The air spacers prevent the reagents from mixing with each other during cartridge preparation, storage, and usage. As an example, we used this "plug-in cartridge" technology to complete a solid-phase immunoassay in a microchannel in 2 min with low-nanomolar sensitivity and demonstrate the diagnosis of HIV in 13 min.