地铁隧道爆破振动测试及时频特征分析

为确保某市地铁隧道安全、高效地爆破开挖,采用网络测振仪测试了隧道掘进爆破时周边建(构)筑物的爆破振速。基于频率切片小波变换开展时频特征分析,首先得到了测振信号的全频带时频分布特征,进而通过5个主成分频率切片区间更进一步精确提取了爆破振动信号时域、频域分布特征,并得到了相应频带内的爆破振动重构分量。实测数据时频特征分析表明,频率切片小波变换具备独特的信号分析优势,适用于地铁爆破振动信号时频特征提取;此次地铁隧道钻爆法开挖产生的质点峰值振速在0.07～0.85 cm/s之间,主频在13.3～68.9 Hz之间,爆破振速处于《爆破安全规程》规定的安全阈值范围内,爆破方案基本合理。     

Theoretical Prediction of Infrared Spectra and Thermodynamic Properties of Glyceryl Nitrates

Glyceryl nitrates are one type of compounds with wide applications in military, medicine, etc. In this study, 6 glyceryl nitrates including NG, DGTN, DGPN, DGHN, TriGPN, and TetraGHN were investigated at the B3LYP/6-31G* level of density functional theory. The infrared spectra were obtained and assigned. The frequencies scaled by a factor of 0.96 were then used to calculate the thermodynamic properties based on the principle of statistic thermodynamics. The thermodynamic properties are correlated with the number of —ONO₂ and —CH₂—O—CH₂—CH(ONO₂)— groups in a linear manner, obviously showing a good group additivity character.     

炮孔间隔装药技术在首钢水厂铁矿台阶深孔爆破中的研究与应用

炮孔间隔装药技术,是露天台阶爆破生产中的一种装药结构.本文通过在首钢水厂铁矿台阶中深孔爆破间隔装药技术的研究与应用,具体论述了此项装药技术的理论基础、爆破设计的基本原则、基本技术参数的研究、以及经济效益的评估,为该项技术在露天矿台阶爆破生产中继续应用提供了有力的证据.     

一种适用于无线传感器网络的跨层高效MAC协议

为了延长网络的寿命,实现能量的高效利用是无线传感器网络应用的主要目标,MAC协议的能效性直接关系到网络的能耗,但采用分层方法的MAC协议无法实现最优的节能效果.本文基于跨层的方法提出了一种能量高效MAC(cross layer energy efficient MAC,CLEE-MAC)协议.该协议在自适应S-MAC(adaptive sensor MAC,AS-MAC)协议基础上,通过利用路由层的路由表信息,改变AS-MAC协议的控制帧格式,有效解决了AS-MAC协议中因"强迫唤醒"造成的能量浪费问题,延长了网络的寿命.理论分析和仿真验证均表明,随着节点密度的增加,CLEE-MAC协议的节能增益随网络密度线性增大.     

Thermodynamics of Fe-P-C in Mn-Based Solutions

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Characteristics of Nitrogen Jet and Its Effect on the Bath in Slag Splashing

ＣｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆＮｉｔｒｏｇｅｎＪｅｔａｎｄＩｔｓＥｆｆｅｃｔｏｎｔｈｅＢａｔｈｉｎＳｌａｇＳｐｌａｓｈｉｎｇＹａｎｇＷｅｎｙｕａｎ①，ＺｈｅｎｇＣｏｎｇｊｉｅ①，ＢａｉＲｕｉｇｕｏ②，ＦｕＺｈｅｎｒｏｎｇ②，ＺｈａｎｇＸｉｎｇｌｉ...     

A new Algorithm for the Solution of under Constraint Graph in Sketch Drawing

A new algorithm for the solution of under constraint graph in sketch drawing is put forward. The directed process of constraint graph is completed by picking concealed constraints of adjacent entities in sketch of few or no dimensions. In this paper, the priority of concealed constraint is given by the different constraint types and constructing orders, and some more priority concealed constraints are forced into obvious ones by the need number of constraint for every node in constraint solution process.     

粉末丁腈橡胶DN 214的工业试验

以兰州石化公司自主开发的粉末丁腈橡胶(PNBR)(牌号为DN214)的中试工艺条件为基础,在3kt/a粉末丁苯橡胶装置上进行了PNBR的工业试验,探讨了胶乳门尼黏度、水胶比(质量比)、凝聚温度、搅拌转速、离心方式对PNBR成粉率的影响。结果表明,当胶乳门尼黏度为70~90、水胶比为6·0~8·0、凝聚温度为45~60℃、搅拌转速为80~100r/min,并采用卧式螺旋卸料离心机时,可以生产出粒径小于0·9mm、成粉率超过96%的PNBR。     

BInfluence of Cerium and Phosphorus onEmbrittlement in Manganese Steels

ＩｎｆｌｕｅｎｃｅｏｆＣｅｒｉｕｍａｎｄＰｈｏｓｐｈｏｒｕｓｏｎＥｍｂｒｉｔｔｌｅｍｅｎｔｉｎＭａｎｇａｎｅｓｅＳｔｅｅｌｓＦＥＮＧＳｏｎｇＹｕｎ；ＷｕＣｈｅｎｇＪｉａｎ；ＬＩＪｉｎｇＨｕｉ￣①ＩｎｆｌｕｅｎｃｅｏｆＣｅｒｉｕｍａｎｄＰｈｏｓｐｈｏｒ...     

Influence of Different Lubricants on Deformation Behaviour of IN 718 Aloy in Hot Compresion Process

ＩｎｆｌｕｅｎｃｅｏｆＤｉｆｅｒｅｎｔＬｕｂｒｉｃａｎｔｓｏｎＤｅｆｏｒｍａｔｉｏｎＢｅｈａｖｉｏｕｒｏｆＩＮ７１８ＡｌｏｙｉｎＨｏｔＣｏｍｐｒｅｓｉｏｎＰｒｏｃｅｓＭａＬｏｎｇｚｈｏｕ①，ＺｈａｎｇＪｉａｎｍｉｎ①，ＺｈｕａｎｇＪｉｎｇｙｕｎ①，Ｚ...