Laser probe ^(40)Ar-^(39)Ar ages of metasomatic K-feldspar from the Hougou gold deposit,northwestern Hebei Province,China

The Hougou gold deposit in northwestern Hebei is a typical K-metasomatism-related gold deposit hosted by K-altered rocks overprinting alkali intrusive rocks. In order to determine the age and pulse intervals of K-metasomatism in this gold deposit, some metasomatic K-feldspars from K-altered rocks are selected to measure their formation time by laser probe 40Ar-39Ar dating method. The new analyzing data show that these metasomatic K-feldspar formed during 202.6 Ma and 176.7 Ma, and the corresponding K-metasomatism and associated gold mineralization occurred in the early stage of Mesozoic era. The pulse intervals of K-metasomatism in the Hougou area are estimated to be about 4 Ma.

Dating of sediment-hosted disseminated-type gold deposit by using ^40Ar/^39Ar laser probe:A case study of Changkeng large-scale gold deposit,China

Hydrothermal clay minerals that formed in the main metallogenic stage of the Changkeng disseminated-type gold deposit in central Guangdong were analyzed by the 40Ar/39Ar laser probe. The results give Ar-Ar isochron ages of 109.9 1.4 to 110.1 1.3 Ma, which are 30 to 50 Ma older than the age of silver ore bodies in the deposit. Both gold and silver mineralizations were not related to hidden granite batholith in the mining district, but probably related to evo-lution of sedimentary basins. This study shows that the 40Ar/39Ar laser probe is a sound dating tool applicable to sediment-hosted disseminated-type gold deposit.

Ultra-violet laser probe measurement of ^(40)Ar/^(39)Ar age profile in phlogopite

Ultra-Violet Laser Ablation Microprobe (UV-LAMP) extraction technique enables the direct investigation of Ar-Ar age profile in crystals, and yields more information on rates and durations of geological process than conven-tional single time snapshots. Phlogopite flakes from lampro-phyre at Pishan dyke in western Kunlun were dated by using an UV laser (l = 213 nm) microprobe with spot analyses. The results show good agreement with those from the conven-tional 40Ar/39Ar step heating experiments. This indicates that the Ar isotopes are distributed homogenously in the phlogopite and the UVLAMP can be a powerful tool in the study of thermal history.

Probe based confocal laser endomicroscopy of the pancreatobiliary system

AIM:To review applications of confocal laser endomicroscopy(CLE) in pancreatobiliary lesions and studies that assessed training and interpretation of images. METHODS: A computerized literature search was performed using OVID MEDLINE, EMBASE, Cochrane library, and the ISI Web of Knowledge from 1980 to October 2014. We also searched abstracts from major meetings that included the Digestive Disease Week, Canadian Digestive Disease Week and the United European Gastroenterology Week using a combination of controlled vocabulary and text words related to p CLE, confocal, endomicroscopy, probe-based confocal laser endomicroscopy, and bile duct to identify reports of trials. In addition, recursive searches and crossreferencing was performed, and manual searches of articles identified after the initial search was also completed. We included fully published articles and those in abstract form. Given the relatively recent introduction of CLE we included randomized trials and cohort studies.R E S U LT S : In the evaluation of indeterminate pancreatobiliary strictures CLE with ERCP compared to ERCP alone can increase the detection of cancerous strictures with a sensitivity of(98% vs 45%) andhas a negative predictive value(97% vs 69%), but decreased the specificity(67% vs 100%) and the positive predictive value(71% vs 100%) when compared to index pathology. Modifications in the classification systems in indeterminate biliary strictures have increased the specificity of p CLE from 67% to 73%. In pancreatic cystic lesions there is a need to develop similar systems to interpret and characterize lesions based on CLE images obtained. The presence of superficial vascular network predicts serous cystadenomas accurately. Also training in acquiring and interpretation of images is feasible in those without any prior knowledge in CLE in a relatively simple manner and computer-aided diagnosis software is a promising innovation. CONCLUSION: The role of p CLE in the evaluation of pancreatobiliary disorders might be better suited for those with an intermediate and low probability.

基于光纤镀膜探针的固体介质中应力波粒子速度测量技术

粒子速度是分析固体介质中应力波传播规律的一个重要参数。结合激光多普勒效应和全光纤干涉测速系统,提出了一种基于光纤镀膜探针的固体介质中应力波粒子速度的测量方法。将光纤镀膜探针嵌入有机玻璃(PMMA)中,距爆心同一半径处,采用0.125 g TNT当量的微型炸药球作为爆炸源,进行填实爆炸产生应力波,通过采集光纤探针端面的运动信息,基于短时傅里叶变换的时频分析方法,解调出端面运动速度,进而反推出粒子速度。实验结果表明:不同光纤镀膜探针测得的速度分别为22.648 m/s、23.505 m/s,将反推的粒子速度与传统的圆环型电磁粒子速度计方法获取到的数据进行对比,两者的相对偏差低于5.00%,验证了光纤镀膜探针测量固体介质中应力波粒子速度的可行性。

激光测距机在线能量监测系统设计

本文基于无人值守条件下对激光测距机发射能量进行直接人工测量较为困难,为了防止激光器能量下降影响激光测距机性能,需要对测距机工作状态进行实时监控这一需求设计了激光测距机在线能量监测系统。对能量探头的结构与检测位置进行了研究,并设计硬件电路实现能量测量。本文设计的在线能量监测系统可以在不影响测距机测距能力的情况下实现kHz量级重频激光测距机的宽量程实时能量监测,并满足小型化、集成化设计要求。

Synchronized off-harmonic probe laser with highly variable pulse duration for laser-plasma interaction experiments

This paper presents the development and experimental utilization of a synchronized off-harmonic laser system designed as a probe for ultra-intense laser±plasma interaction experiments. The system exhibits a novel seed-generation design,allowing for a variable pulse duration spanning over more than three orders of magnitude, from 3.45 picoseconds to 10 nanoseconds. This makes it suitable for various plasma diagnostics and visualization techniques. In a side-view configuration, the laser was employed for interferometry and streaked shadowgraphy of a laser-induced plasma while successfully suppressing the self-emission background of the laser±plasma interaction, resulting in a signal-to-self-emission ratio of 110 for this setup. These properties enable the probe to yield valuable insights into the plasma dynamics and interactions at the PHELIX facility and to be deployed at various laser facilities due to its easy-to-implement design.

共聚焦显微成像系统P9000图像质量评价临床研究

目的评价共聚焦显微成像系统P9000检测人体消化道相关组织的有效性和安全性。方法选取2021年8月至2022年6月在北京中医药大学东方医院和山东大学齐鲁医院行内镜检查的96例患者为研究对象。94例受试者纳入全分析集(Full Analysis Set,FAS),90例患者纳入符合方案集(Per Protocol Set,PPS)。通过多中心、随机、自身对照研究,统计共聚焦显微成像系统P9000与国际公认的Cellvizio®系统检测人体消化道相关组织的图像质量评分一致性和95%CI,以及两组的操作时间和不良反应发生情况。结果FAS和PPS两款器械图像质量评分一致性和95%CI分别为92.55%(87.25%~97.86%)和92.22%(86.69%~97.76%),两者95%CI下限均大于目标值84.6%;两组器械操作时间相当,差异无统计学意义(P>0.05);两组均无设备导致的不良反应发生。结论共聚焦显微成像系统P9000的临床使用有效性和安全性达到了设计要求,值得临床推广应用。

数控加工中激光探头光轴垂直度误差标定方法

在数控加工中,由于无法精准地获取激光探头光轴垂直度误差,因此,为了解决这一问题,提出数控加工中激光探头光轴垂直度误差标定方法。通过构建数学模型,确定激光探头光轴的基准平面,并对激光探头光轴的理想垂直度展开计算。对激光探头光轴图像实施二值化去噪操作,并对其展开边界扩展处理。通过Harris算子提取激光探头光轴垂直度特征信息,调整光轴与物面的垂直度,实现激光探头光轴垂直度误差标定。实验结果表明,所提方法对激光探头光轴垂直度误差标定精准度高,误差值保持在-0.5 mm~0.5 mm,表明所提方法的性能好。

松辽盆地砂岩型铀矿铀含量配分比例的半定量分析

钱家店铀矿是位于松辽盆地南部的复成因砂岩型铀矿,受表生淋滤、辉绿岩中低温热液和深部油气等多流体影响,目前铀矿物赋存状态尚有一定争议,铀在矿石内不同矿物中的配分尚不明确。为了进一步明确铀赋存状态和在不同矿物中的配分,计算钱家店矿石中不同矿物中铀的配分比例,本文运用岩矿鉴定、铀化学逐级提取、电子探针和激光剥蚀电感耦合等离子体质谱(LA-ICP-MS)微区原位分析技术开展综合测试分析。明确了钱家店铀矿物的赋存状态,认为钱家店铀矿物以吸附态为主,约占总铀含量的80%,结合态铀矿物或含铀矿物约占比20%。其中吸附态铀矿物主要富集在方解石等碳酸盐矿物中,占总铀含量的47.86%,其次是在黏土矿物中占17.94%,在铁锰氧化物矿物中占12.21%。独立铀矿物是与黄铁矿密切共生的沥青铀矿为主,约占铀总含量的9.07%,另有少量含钛铀矿物和铀石约占5.08%。这种矿石中各碎屑组分中铀的占比量化研究,为矿床地浸开采及资源量计算提供依据。

探头式共聚焦激光显微内镜对胃底腺息肉的诊断价值

目的探讨探头式共聚焦激光显微内镜(probe-based confocal laser endomicroscopy,pCLE)在胃底腺息肉诊断中的价值。方法纳入2023年6-12月于陆军军医大学第一附属医院消化内科内镜中心行普通白光内镜(white light image,WLI)提示胃息肉患者63例,收集患者临床资料、白光内镜图像、窄带成像内镜(narrow band imaging,NBI)图像、pCLE内镜图像以及术后组织病理,统计验证胃底腺息肉在pCLE内镜下特点,分别计算不同内镜诊断的灵敏度、特异性、准确度、一致性。结果胃底腺息肉在pCLE内镜下主要表现为胃小凹开口拉长,“手牵手样”胃小凹开口,小凹开口周围血管规则,无荧光素渗出。WLI的灵敏度、特异度、准确度、一致性分别为:72.73%、75.00%、73.13%、0.343(胃底腺息肉),81.82%、71.43%、71.64%、0.354(增生性息肉);NBI的灵敏度、特异度、准确度、一致性分别为87.27%、83.33%、86.57%、0.673(胃底腺息肉);81.82%、85.71%、85.07%、0.554(增生性息肉);pCLE的灵敏度、特异度、准确度、一致性分别为92.73%、91.67%、92.53%、0.769(胃底腺息肉),90.91%、94.64%、94.03%、0.797(增生性息肉)。pCLE的灵敏度、特异度等均优于WLI和NBI,与病理诊断的一致性较好。结论pCLE可用于胃底腺息肉的诊断。

基于激光跟踪仪T-Probe的数字化装配检测

激光跟踪仪测量系统在飞机装配工装制造和工装检测方面的应用已趋于成熟,但在产品外形测量中应用不是十分广泛。通过对Leica AT901-MR激光跟踪仪测量系统功用及原理分析,重点对T-Probe的使用进行研究,摸索和总结了一套适用于型胎、大型装配件等的测量方法,具有推广价值,同时为进一步研究飞机数字化装配检测技术打下良好基础。

A High-Resolution Measurement Method for Inner and Outer 3D Surface Profiles of Laser Fusion Targets Using a Laser Differential Confocal–Atomic Force Probe Technique

The high-resolution and nondestructive co-reference measurement of the inner and outer threedimensional(3D)surface profiles of laser fusion targets is difficult to achieve.In this study,we propose a laser differential confocal(LDC)–atomic force probe(AFP)method to measure the inner and outer 3D surface profiles of laser fusion targets at a high resolution.This method utilizes the LDC method to detect the deflection of the AFP and exploits the high spatial resolution of the AFP to enhance the spatial resolution of the outer profile measurement.Nondestructive and co-reference measurements of the inner profile of a target were achieved using the tomographic characteristics of the LDC method.Furthermore,by combining multiple repositionings of the target using a horizontal slewing shaft,the inner and outer 3D surface profiles of the target were obtained,along with a power spectrum assessment of the entire surface.The experimental results revealed that the respective axial and lateral resolutions of the outer profile measurement were 0.5 and 1.3 nm,while the respective axial and lateral resolutions of the inner profile measurement were 2.0 nm and approximately 400.0 nm.The repeatabilities of the rootmean-square deviation measurements for the outer and inner profiles of the target were 2.6 and 2.4 nm,respectively.We believe our study provides a promising method for the high-resolution and nondestructive co-reference measurement of the inner and outer 3D profiles of laser fusion targets.

激光云粒子成像探测仪研制

为了研究云粒子微观特性,采用激光成像技术、高斯光束匀化处理技术、高分辨率阵列探测器以及图像抽帧还原算法,研制出激光云粒子成像仪。通过地面模拟测量及实际飞行试验,对仪器性能进行了测试。结果表明,研制仪器可实现对25μm~1550μm云粒子的成像,分辨率为25μm,粒径测量误差小于9.5%;实测的冰晶粒子形态符合云粒子自然分布规律,粒子尺度谱符合指数分布,决定系数在0.58~0.97之间。该研制仪器可为云降水微物理研究提供基础观测数据。

Determination of the temporal structure of femtosecond laser pulses by means of laser-induced air plasma

A new approach is presented to reveal the temporal structure of femtosecond laser pulses by recording the correspond- ing time-resolved shadowgraphs of the laser-induced air plasma. It is shown that the temporal structures of femtosecond laser pulses, normally not observable by the ordinary intensity autocorrelator, can be detected through intuitively analyz- ing the ultrafast evolution process of the air plasma induced by the femtosecond laser pulses under examination. With this method, existence of pre- and post-pulses has been clearly unveiled within the time window of 4-150 fs in reference with the main 50-fs laser pulses output from a commercial 1-kHz femtosecond laser amplifier. The unique advantage of the proposed method is that it can directly provide valuable information about the pulse temporal structures＇ effect on the laser-induced ionization or material ablation.

Electrical Characteristics of Plasma Plume During Pulse Wave Laser Welding

To detect the real-time plasma plume during pulse wave Nd:YAG laser welding, experimental studies were conducted based on asynchronous signal acquisition system. The electrical signals of the laser-induced plasma plume were obtained by a passive acquisition system. The plume was directly observed and recorded using synchronous high-speed camera. The results showed that the waveform of the signals was in accordance with the periodical laser power. The signals decreased after the laser was turned on and fl uctuated relatively steadily on the stable stage and then increased to 0 V after the laser beam was turned off . The decreasing time of the electrical signals was roughly 1.0 ms, and it decreased with the increasing peak power. However, the average power had insignifi cant eff ect on the signal decreasing time.

飞秒激光微加工中诱导空气等离子体的超快观测研究

通过搭建飞秒时间分辨的泵浦探测阴影成像系统,研究了聚焦的飞秒激光脉冲产生空气等离子体的瞬态演化特性,并对不同聚焦条件下空气等离子体的时间特性进行了数值模拟。实验结果表明:聚焦的飞秒激光电离空气等离子体的电子瞬态密度峰值先升高后缓慢下降;同时得到了高时间分辨下的电离速度变化与电子数密度的空间分布。计算结果显示:更高的单脉冲能量对应更高的饱和电子数密度,高数值孔径聚焦条件下隧穿电离也更早出现,表明飞秒时间分辨的泵浦探测阴影成像可为超快激光微加工的瞬态过程提供观测手段,同时可对超快激光微加工过程中的等离子屏蔽效应提供机理解释与加工工艺的优化参考。

高重频硬X射线自由电子激光脉冲到达时间诊断方法研究

X射线自由电子激光(XFEL)脉冲时间诊断技术常用于实验站附近XFEL脉冲和配套激光的相对到达时间探测,是飞秒级XFEL泵浦探测实验的重要辅助技术,为XFEL和激光泵浦探测实验中两种脉冲对准提供参考信号.随着XFEL向高重频、短脉冲发展,对时间诊断中的诊断频率、泵浦样品和分辨率提出了更高的要求.该技术通过泵浦探测和光学互相关实现,当XFEL脉冲入射高带宽半导体样品瞬间,导致样品复折射率突变,使XFEL到达时间编码于突变空间.本文基于空间编码和光谱编码两种方法,研发设计了XFEL单脉冲到达时间诊断装置;并通过Beer’s吸收理论和原子散射理论对X射线与样品作用过程进行模拟,研究了该过程中X射线吸收与折射率突变的响应程度,完善了样品的分析选择模型;对光谱编码中的啁啾脉冲调制进行分析,得到色散介质和脉冲本征参数对诊断分辨率的影响.该研究对XFEL脉冲到达时间诊断装置的应用具有指导意义.

双路偏振结构的激光多普勒测速系统

为了消除光束倾角带来的不确定性,本文建立了一种双路偏振式激光多普勒测速系统。该系统使用双光束双探头结构来探测物体的运动信息。首先,通过转动实验精确获得双光束间的夹角大小,对于任意光束倾角,本文采用双探头装置收集运动物体表面的散射光束,结合双路偏振式光路结构,得到两路干涉信号的多普勒频移。然后,创新性采用了细化分帧算法对两路干涉信号进行实时解调,通过两路速度分量的合成得到物体真实速度。实验结果表明:速度在10 mm/min~1500 mm/min范围内,测量值与理论值之间的平均误差可以达到1%~5%。在非平稳运动过程中,通过细化分帧算法修正后的v-t图像RMSE均值为1.19 mm/min。该系统结构满足速度测量的稳定可靠、精度高、抗干扰能力强等要求。

基于激光熔融制样分析玄武质无球粒陨石的主、微量元素

无球粒陨石的主、微量元素组成对于类地行星壳-幔分异和岩浆研究演化具有重要意义。但由于样品稀缺,使用传统方法分析无球粒陨石的全岩主、微量元素组成有较大局限。本文在样品粉末压片的基础上,采用激光熔融制取玻璃,并结合电子探针和激光剥蚀电感耦合等离子体质谱(LA-ICP-MS)对标样和Eucrite样品进行原位分析。结果表明,主量元素中除少数元素(Na、K和P等)外,绝大多数元素的分析准确度都优于5%;微量元素除少数元素外(Ni、Ga、Tb、Tl和U等),绝大多数元素的分析准确度都在5%~10%范围。本方法为低损耗(~30 mg)、快速准确获取具有较高Mg、Fe含量的玄武质无球粒陨石样品全岩的主、微量元素组成提供了一种新的途径。