Millisecond dynamics of colloidal suspension studied by X-ray photon correlation spectroscopy at the Shanghai Synchrotron Radiation Facility

X-ray photon correlation spectroscopy(XPCS)has emerged as a powerful tool for probing the nanoscale dynamics of soft condensed matter and strongly correlated materials owing to its high spatial resolution and penetration capabilities.This technique requires high brilliance and beam coherence,which are not directly available at modern synchrotron beamlines in China.To facilitate future XPCS experiments,we modified the optical setup of the newly commissioned BL10U1 USAXS beamline at the Shanghai Synchrotron Radiation Facility(SSRF).Subsequently,we performed XPCS measurements on silica suspensions in glycerol,which were opaque owing to their high concentrations.Images were collected using a high frame rate area detector.A comprehensive analysis was performed,yielding correlation functions and several key dynamic parameters.All the results were consistent with the theory of Brownian motion and demonstrated the feasibility of XPCS at SSRF.Finally,by carefully optimizing the setup and analyzing the algorithms,we achieved a time resolution of 2 ms,which enabled the characterization of millisecond dynamics in opaque systems.

Application of Hilbert-Huang transform based delay time identification in optimization of short millisecond blasting

The accurate identification of delay time in millisecond blasting plays an important role in the optimization of blasting design and reduction of vibration effect. Through a case study of a surge shaft blasting project, the capability of the EMD （empirical mode decomposition） method in identifying the delay time of short millisecond blasting with precise initiation was compared with the instantaneous energy method based on Hilbert-Huang transform （HHT）. The recognition rate of the EMD method was more than 80%, while the instantaneous energy method was less than 25%. By analyzing the instantaneous energy of single-hole blasting signal, it was found that the instantaneous energy method was adaptable to millisecond blasting with delay time longer than half of the energy peak period. The EMD method was used to identify delay time of millisecond blasting in Zijinshan open-pit mine. According to the identification results, the blasting parameters were optimized for controlling the blast-induced vibration and reducing the large block ratio. The field data showed that the velocity peak of ground vibration was reduced by more than 30%under almost the same maximum charge per delay by the optimization of delay time and detonating detonators. Combining with slag-remaining blasting and burden optimization of the first row, the large block ratio was reduced to less than 3%. The research results proved that the identification method based on HHT was feasible to optimize the blasting design. The identification method is also of certain reference value for design optimization of other similar blasting projects.

Influence of millisecond time,charge length and detonation velocity on blasting vibration

The law of blasting vibration caused by blasting in rock is very complex.Traditional numerical methods cannot well characterize all the influencing factors in the blasting process.The effects of millisecond time,charge length and detonation velocity on the blasting vibration are discussed by analyzing the characteristics of vibration wave generated by finite length cylindrical charge.It is found that in multi-hole millisecond blasting,blasting vibration superimpositions will occur several times within a certain distance from the explosion source due to the propagation velocity difference of P-wave and S-wave generated by a short column charge.These superimpositions will locally enlarge the peak velocity of blasting vibration particle.The magnitude and scope of the enlargement are closely related to the millisecond time.Meanwhile,the particle vibration displacement characteristics of rock under long cylindrical charge is analyzed.The results show that blasting vibration effect would no longer increase when the charge length increases to a certain extent.This indicates that the traditional simple calculation method using the maximum charge weight per delay interval to predict the effect of blasting vibration is unreasonable.Besides,the effect of detonation velocity on blasting vibration is only limited in a certain velocity range.When detonation velocity is greater than a certain value,the detonation velocity almost makes no impact on blasting vibration.

Vibration Superposition in Tunnel Blasting with Millisecond Delay

According to explosion dynamics and elastic wave theory, the models of particle vibration velocity for simultaneous blasting and milliseeond blasting are built. In the models, influential factors such as delay interval and charge quantity, are considered. The calculated vibration velocity is compared with the field test results, which shows that the theoretical values are close to the experimental ones. Meanwhile, the particle vibration velocity decreases quickly with time due to the damping of rock mass and has a harmonic motion, and the particle vibration velocity of millisecond blasting has short interval. The superposition of particle vibration velocities may reduce vibration because of wave interference, or magnify the surrounding rock response to the blastinginduced vibration.

The Process of a Laser-Supported Combustion Wave Induced by Millisecond Pulsed Laser on Aluminum Alloy

We study the process of a laser-supported combustion wave （LSCW） when an aluminum alloy is irradiated by a millisecond pulse laser based on the method of laser shadowgraphy. Under the condition of different laser parameters, the obtained results include the velocity, ignition threshold of LSCW and the variation law. The speed of LSCW increases with the laser energy under the same irradiation laser pulse width, and the speed of LSCW reduces with the increase of the laser pulse width under the same irradiation laser energy. Moreover, the ignition time of LSCW becomes shorter by increasing the laser number of the pulse and is not effected by changing the frequencies, when keeping the laser pulse width and energy unchanged. The results of the study can be applied in the laser propulsion technology and metal surface laser heat treatment, etc.

Effects of dynamo magnetic fields on observational properties of accreting millisecond X-ray pulsars

In this paper,we have investigated accreting millisecond X-ray pulsars,which are rapidly rotating neutron stars in low-mass X-ray binaries.These systems exhibit coherent X-ray pulsations that arise when the accretion flow is magnetically channeled to the stellar surface.Here,we have developed the fundamental equations for an accretion disk around accreting millisecond X-ray pulsars in the presence of a dynamo generated magnetic field in the inner part of the disk.We have also formulated the numerical method for the structure equations in the inner region of the disk and the highest accretion rate is enough to form the inner region of the disk,which is overpowered by radiation pressure and electron scattering.Finally,we have examined our results with the effects of dynamo magnetic fields on accreting millisecond X-ray pulsars.

Investigating the Thermal Stress of Millisecond Pulsed Laser Irradiation on Charge-Coupled Devices

In this study, a two-dimensional model describing thermal stress on a charge-coupled device (CCD) induced by ms laser pulses was examined. Considering the nonlinearity of the CCD’s material parameters and the melting phase transition process of aluminum electrode materials was considered by using equivalent specific heat capacity method, the physical process where a laser pulse irradiating a CCD pixel array was simulated using COMSOL Multiphysics software. The temperature field and thermal stress field were calculated and analyzed. In order to clarify the mechanism producing damage on the CCD detector, Raman spectra from silicon were measured with a micro-Raman spectrometer to determine stress change in the CCD chip. The procedure presented herein illustrates a method for evaluating strain in a CCD after laser irradiation.

Magnetic Loop Oscillation Associated with a Large Type-Ⅳμ Burst and Millisecond Spike Emission

A rare large Type Ⅳμ burst, appeared above active region NOAA/USAF 5278 was observed at Yunnan Observatory with Phoenix Ⅱ Microwave Spectrometer at three frequencies (4 00, 2 84 and 1 42 GHz) on December 16, 1988. The burst consisted of 5 main peaks with a quasiperiod of 12 5 min, on which many complex millisecond spike emissions were superimposed. Within the first main peak there were 8 secondary peaks with a quasi period of 98s (at 4 00 GHz), 72s (2 84 GHz) and 60s (1 42 GHz). A semi quantitative explanation is given for the variation of the quasi period with frequency in terms of MHD modulated oscillations in the magnetic flux tube.

Polynomial regression calculation of the Earth's position based on millisecond pulsar timing

Prior to achieving high precision navigation of a spacecraft using X-ray observations, a pulsar rotation model must be built and analysis of the precise posi- tion of the Earth should be performed using ground pulsar timing observations. We can simulate time-of-arrival ground observation data close to actual observed values before using pulsar timing observation data. Considering the correlation between the Earth＇s position and its short arc section of an orbit, we use polynomial regression to build the correlation. Regression coefficients can be calculated using the least square method, and a coordinate component series can also be obtained; that is, we can calcu- late Earth＇s position in the Barycentric Celestial Reference System according to pulse arrival time data and a precise pulsar rotation model. In order to set appropriate param- eters before the actual timing observations for Earth positioning, we can calculate the influence of the spatial distribution of pulsars on errors in the positioning result and the influence of error source variation on positioning by simulation. It is significant that the threshold values of the observation and systematic errors can be established before an actual observation occurs; namely, we can determine the observation mode with small errors and reject the observed data with big errors, thus improving the positioning result.

Microwave Millisecond Spikes on July 30, 1997

The characteristics of the millisecond spikes with short durations and weak flux densities which were observed with high time resolution (1 ms) during a great type Ⅳ solar radio burst of 1990 July 30 are introduced. The time profiles of the spikes are statistically analyzed and the parameters of the spike source are also estimated.

Aggregation-induced conversion from TADF to phosphorescence of gold(I)complexes with millisecond lifetimes

Long-lived luminescent materials possess wide application prospects in various areas,but their constructions still face a huge challenge,especially the achievement in solution.Manipulating aggregate is an effective method to attain intriguing luminescence,thus it is expected to build long-lived materials in solution.In this work,a series of new gold(I)complexes were developed by employing unique carbazole and phosphine as the ligands,and these resulting systems exhibited rare long lifetimes of milliseconds in the aggregate state.It was well unveiled that these complexes emitted blue thermally activated delayed fluorescence(TADF)with the lifetimes of several microseconds in dilute solution;while orange-red phosphorescence with much longer lifetimes of several milliseconds were achieved in the aggregate state.To our knowledge,this is the first implementation of aggregation-induced conversion from TADF to phosphorescence.Based on their excellent luminescent properties,we successfully applied these complexes in cell imaging and inhibition of cancer cells.

分层一次爆破成井精确延时爆破参数研究

为了研究精确延时微差起爆对一次成井分层爆破效果的影响,理论计算了层内孔间微差时间,利用LS-DYNA软件,采用JH-2岩石模型,模拟了大直径深孔一次成井爆破中的精确延时分层起爆,分析了井筒岩石的损伤演化过程,试验验证了延期时间参数。结果表明,层间采用18 ms延期时间时,爆破效果最佳。结合理论分析和数值模拟结果确定了一次成井的延期时间方案。井筒的成形大致相似,其特征截面面积相似度在83.4%~96.6%之间。通过理论分析、数值模拟和现场试验获得了一次爆破成井工程的精确延时微差分层爆破方法,具有实际应用价值。

基于DIC的露天矿山微差爆破模型试验及数值模拟

随着电子雷管在露天矿山台阶爆破中的全面使用,微差爆破技术得到进一步发展,如何通过调整孔间延时提高炮孔之间相互作用力,成为矿山爆破技术的研究重点。基于混凝土模型模拟露天矿山微差爆破,建立高速摄影技术与数字图像相关(DIC)试验系统,基于全场微应变、高速摄影技术和数值模拟对不同孔间延时条件下的炮孔间裂纹发展过程进行了研究。结果表明:爆炸载荷下模型表面裂纹附近的应变持续时间约为3 ms,孔间延时为3 ms时下一个炮孔起爆能够提高炮孔之间的相互作用力;通过数值模拟展示了测点的压力分布特征,在孔间延时为3 ms时测点压力最大,验证了模型试验的准确性;利用MATLAB对数值模拟结果分析发现,孔间延时为3 ms时其破碎程度最佳,与模型试验结果具有较好的一致性;使用高速摄影技术结合DIC方法为研究炮孔之间的相互作用力及裂纹扩展提供了新思路。

微差爆破在港口工程中的应用

考虑到地质条件的复杂性和输油管等重要设施的存在,水下炸礁作为港口建设和航道疏浚中的重要工作手段需要确保工程的安全性。为了减少爆破产生的冲击波、震荡及爆破涌浪对周围环境的危害,对地质条件进行充分分析,并选取合适的爆破自由面以降低爆破振动的影响。在进行水下炸礁工作时,开展试爆研究,通过调整爆破参数如装药量和引爆时间,达到最佳的效果;通过设计最佳的装药结构,提高爆破的稳定性和安全性。研究成果可为地质坚硬、水深较深、施工条件复杂以及需要确保施工区内重要建筑安全的水下炸礁工程提供技术参考。

露天矿山台阶爆破合理微差时间优选及应用

为了降低露天台阶爆破后的岩石块度,减少二次破碎成本,根据杨家岭矿山的实际地质情况建立有限元模型,研究了微差时间对岩石损伤程度的影响,分析了关键测点随延期时间变化的规律,最后开展现场试验并利用块度分析软件WipFrag4.0对爆后岩石进行块度分析。结果表明:随着微差时间的增加,岩石的损伤程度先增加后减小,在孔间、排间微差时间分别为40、70 ms时,岩石的损伤程度达到最大;通过在现场开展爆破试验发现,在孔间延期时间为35、40 ms,排间延期时间为65、70 ms时,块度主要集中在10 cm处,块度大于31.6 cm的占比分别为21.26%、23.19%,明显小于其他方案;分析后发现爆后块度分布规律与数值模拟得到的岩石损伤程度变化规律具有较好一致性,验证了数值模拟的准确性;通过数值模拟岩石损伤程度的量化与现场爆破试验相结合,为后续研究岩石损伤提供新思路。

数码电子雷管在露天矿爆破中延期时间优化探讨

针对新疆某露天矿复杂岩性台阶爆破大块率高,炸药单耗大,爆破效果差等问题,利用XF型数码电子雷管高精度、高安全度的优势,采用控制变量法,在该矿东帮四个标段445~595水平分别进行了59场不同可爆性岩体孔间、排间最优微差时间的爆破试验。通过对爆堆形状、矿岩块度及炸药单耗的统计,确定了最优的孔间和排间延期时间。试验结果表明:针对泥岩为主,部分细砂岩性台阶,孔间、排间延时/米分别取5.9 ms/m和14 ms/m时,爆堆平整,块度均匀;针对砂岩为主,部分泥岩岩性台阶,孔间、排间延时/米分别取2.7 ms/m和14.2 ms/m时,爆堆形状及规格合理,大块率较低。将试验结果应用于该矿现场生产,炸药平均单耗较往年同比降低4.03%,大块率降低1.8%。该项研究表明:针对复杂地质条件选取合理的孔间、排间延时时间,可有效降低炸药单耗,节约成本,且爆堆平整,块度均匀,降本增效显著。本次试验所确定的孔间排间延时时间,可为准东地区同等地质条件下泥岩、砂岩混合台阶爆破延时时间选取提供重要的现场数据。

综采工作面过陷落柱毫秒延时松动爆破研究与应用

为了解决3203综采工作面过陷落柱困难的问题,结合陷落柱现场地质条件,提出基于毫秒延时起爆技术的松动爆破专项方案,并采用理论设计、数值模拟和现场试验相结合的方法,对比总结同时起爆模型和毫秒延时起爆模型的裂隙扩展模式和应力传播规律,分析在顶板处质点的振速和位移变化规律。研究表明:通过毫秒延时松动爆破可以使相邻炮孔间形成贯通裂隙,相比于同时起爆,延时起爆模型优先创造自由面,从而破碎陷落柱岩石并减少爆破飞石,解决了综采面过陷落柱困难的问题。毫秒延时起爆相比于同时起爆,对顶板的峰值合振速减小了9 cm/s,对顶板的峰值合位移减小了0.095 mm。现场试验发现,松动爆破对陷落柱的破碎效果明显,陷落柱岩石强度得到有效减弱。实践证明,毫秒延时松动爆破技术能够极大提高截煤作业效率,保护采煤区顶板,经济效益显著。

Accelerated plasma degradation of organic pollutants in milliseconds and examinations by mass spectrometry

The rapid degradation of organic pollutants,process monitoring and online controlling to obtain advanced products and decreased by-products are great and challenging tasks in environmental treatments.Herein,an accelerated plasma degradation in milliseconds was achieved by combining electrospray-based acceleration and plasma-based degradation.Taking the degradation of chloroaniline as an example,97%of the degradation can be achieved in milliseconds.The velocity distribution of droplets was determined to be 40-50 m/s after being degraded for 0.30 ms,which exhibited different degradation behaviors in different milliseconds.Simultaneously,by virtue of the real-time and on-line detection ability of ambient mass spectrometry,intermediates,by-products and advanced products were monitored.Therefore,degradation mechanisms for different degradation times were proposed,which would provide theoretical guidance on obtaining efficient and green degradation.The fabrication,examining and understanding of accelerated plasma degradation not only enlarged application of accelerated reactions,but also promoted green and efficient degradation for environmental treatments.

大型金属矿山深孔采矿两率指标管控技术创新与应用

石人沟铁矿回采采用深孔凿岩穿孔爆破,原垂直走向布置矿房和沿矿体走向布置矿房在矿房布置和穿孔方式上未按现场变化进行技术优化,导致深孔凿岩过程中未能根据矿体实际产状进行精准调整,造成矿体上盘和下盘矿石严重损失贫化,直接影响矿石两率指标,造成矿山生产成本偏高,使得矿石资源未能被充分利用。对此,技术人员进行矿房设计优化及凿岩施工过程管控,提高矿体内有效凿岩率,避免矿体外凿岩造成的工程浪费,矿体上盘和下盘的损失贫化率近乎于零。结合现场生产实际,精准实施多排毫秒延期爆破技术提高爆破效果,有效控制了大型矿山深孔采矿两率指标,提高了矿山生产效益。

微差爆破挤淤处理抛石堤坡肩残留淤泥施工工艺研究

某机场陆域形成工程采用爆破挤淤形成抛石防波堤,在淤泥挤出侧形成了100 m~150 m的次生淤泥滩涂带,宽度较大,传统爆破挤淤工艺无法应用,如不处理又不能满足设计要求。针对上述情况,在东防波堤试验段通过陆上冲击钻成孔,将药包布置在坡肩残留淤泥中,同时在垂直海堤轴线海侧以外5m~7m处布置药包,采用两种延迟工艺的微差爆破挤淤施工。结果表明,采用以上药包布置方案,单孔药量为72 kg时,微差爆破可以有效处理抛石挤淤堤坡肩深层位置残留淤泥,钻孔结果表明无淤泥残留。该工艺可解决类似工程的淤泥残留,有现实指导作用。