A COMBINED MEASUREMENT SYSTEM FOR UV/V IN SITU SPECTROELECTROCHEMICAL STUDY

A microcomputer-based UV/V in situ spectroelectrochemical measurement system has been developed.This paper presents a description of the experimental details regarding the methods and equipment.

Combined measurement of thyroid and plasma homocysteic acid for detecting the severity of vascular dementia

BACKGROUND: Recent researches demonstrate that onset of cerebral infarction always accompanies with obvious changes of function of thyroid axis; while, high-homocysteic acidemia has been proved as one of risk factors of vascular dementia and Alzheimer disease. Meanwhile, it is found that level of plasma homocysteic acid is positive correlation with injured degrees of cognitive function and brain damage. OBJECTIVE: To observe the changes of function of thyroid and level of homocysteic acid among patients with vascular dementia and compare with those patients without dementia cerebral infarction. DESIGN: Randomized grouping and contrast observation. SETTING: Department of Neurology, People’s Hospital Affiliated to Yunyang Medical College, South China Hospital of Wuhan University. PARTICIPANTS: A total of 38 patients with vascular dementia were hospitalized in the Department of Neurology, People’s Hospital Affiliated to Yunyang Medical College from February 2004 to December 2005. All patients met the diagnostic criteria of the Fourth Edition of Diagnostic and Statistical Manual of Mental Disorder (DSM-IV) established by American Psychiatric Association. Based on educational degrees, Mini-mental Status Examination (MMSE) was classified into illiteracy (≤ 17 points), education of primary school (educational duration ≤ 6 years, ≤ 24 points) and education of middle school or above (educational duration > 6 years, ≤ 24 points). Forty patients with non-dementia cerebral infarction were regarded as the control group and checked with CT examination. There were no significant differences of sex and age between the two groups. All patients and relatives were provided the consent. METHODS: Within 24 hours after hospitalization, patients with vascular dementia received MMSE scores, and the degrees were classified based on the scoring results: mild (20-24 points), moderate (10-19 points) and severe (below 10 points). Levels of thyroxine were measured with radioimmunodetection and content of homocysteic acid was measured with high performance liquid chromatogram (HPLC) electrochemical detection. MAIN OUTCOME MEASURES: Levels of homocysteic acid and thyroxine among patients with vascular dementia and non-dementia cerebral infarction. RESULTS: A total of 38 patients with vascular dementia and 40 patients with non-dementia cerebral infarction were involved in the final analysis. ① Levels of triiodothyronine (T3), thyroxine (T4) and free T3 (FT3) were (0.9±0.4) μg/L, (92.9±26.4) μg/L and (3.9±1.8) pmol/L in vascular dementia group respectively, which were higher than those in control group [(1.3±0.3) μg/L, (110.2±28.7) μg/L, (7.2±2.1) pmol/L, t =2.766 6-7.433 6, P < 0.01]; while, level of homocysteic acid was (29.57±7.12) μmol/L in vascular dementia group, which was higher than that in control group [(24.53±4.98) μmol/L, t =3.637 7, P < 0.01]. There were no significant differences of free T4 (FT4) and thyrotropic-stimulating hormone (TSH) between the two groups (P > 0.05). ② Levels of FT3 of patients with mild, moderate and severe vascular dementia were (1.0±0.2), (0.9±0.1) and (0.8±0.1) μg/L, respectively; levels of homocysteic acid were (26.52±4.84), (29.59±5.56) and (32.71±6.17) μmol/L, respectively. There were significant differences among patients at the three degrees of vascular dementia (F =3.59-32.4, P < 0.01). However, there were no significant differences of T4, FT4 and TSH among the three kinds of patients (P > 0.05). CONCLUSION: Levels of thyroxine of patients with vascular dementia decrease; however, levels of homocysteic acid increase. Therefore, the results can indirectly reflect severities of vascular dementia.

A Highly Sensitive Femtosecond Time-Resolved Sum Frequency Generation Vibrational Spectroscopy System with Simultaneous Measurement of Multiple Polarization Combinations

Characterization of real-time and ultrafast motions of the complex molecules at surface and interface is critical to understand how interracial molecules function. It requires to develop surface-sensitive, fast-identification, and time-resolved techniques. In this study, we employ several key technical procedures and successfully develop a highly sensitive femtosecond time-resolved sum frequency generation vibrational spectroscopy （SFG-VS） system. This system is able to measure the spectra with two polarization combinations （ssp and ppp, or psp and ssp） simultaneously. It takes less than several seconds to collect one spectrum. To the best of our knowledge, it is the fastest speed of collecting SFG spectra reported by now. Using the time-resolved measurement, ultrafast vibrational dynamics of the N-H mode of α-helical peptide at water interface is determined. It is found that the membrane environment does not affect the N-H vibrational relaxation dynamics. It is expected that the time-resolved SFG system will play a vital role in the deep understanding of the dynamics and interaction of the complex molecules at surface and interface. Our method may also provide an important technical proposal for the people who plan to develop time-resolved SFG systems with simultaneous measurement of multiple polarization combinations.

Nondestructive analysis by combined X-ray tomography on a synchrotron radiation facility

A nondestructive X-ray analysis technique combining transmission tomography, fluorescence tomography and Compton tomography based on synchrotron radiation is described. This novel technique will be an optional experimental technique at SSRF's hard X-ray micro-focusing beamline under construction at present. An experimental result of combined X-ray tomography is obtained in NE-5A station of PF. The reconstructed images of test objects are given.

Combining Cubic Spline Interpolation and Fast Fourier Transform to Extend Measuring Range of Reflectometry

The reflectometry is a common method used to measure the thickness of thin films. Using a conventional method,its measurable range is limited due to the low resolution of the current spectrometer embedded in the reflectometer.We present a simple method, using cubic spline interpolation to resample the spectrum with a high resolution,to extend the measurable transparent film thickness. A large measuring range up to 385 m in optical thickness is achieved with the commonly used system. The numerical calculation and experimental results demonstrate that using the FFT method combined with cubic spline interpolation resampling in reflectrometry, a simple,easy-to-operate, economic measuring system can be achieved with high measuring accuracy and replicability.

Theoretical Study of Multi-Theodolite Measurement System

In the field of aerospace, theodolite system is often used in the inspection of large object. A new measurement system that consists of four theodolites is presented in this paper, with which the "blind" problem raised in Original dual-theodolite system can be overcome. The principle of multi-theodolite system, together with the mathematicalmodel (both of calibration and of measurement) is given. And also the calibration process is discussed.

Perforation optimization of layer-penetration fracturing for commingling gas production in coal measure strata

Optimization of fracturing perforation is of great importance to the commingling gas production in coal measure strata.In this paper,a 3 D lattice algorithm hydraulic fracturing simulator was employed to study the effects of perforation position and length on hydraulic fracture propagation in coal measures of the Lin-Xing block,China.Based on field data,three lithologic combinations are simulated:1)a thick section of coal seam sandwiched by sandstones;2)a thin coal seam layer overlay by gas-bearing tight sandstone;3)two coal seams separated by a thin layer of sandstone.Our simulation shows that perforation position and length in multi-layer reservoirs play a major role in hydraulic fracture propagation.Achieving maximum stimulated volume requires consideration of lithologic sequence,coal seam thickness,stress states,and rock properties.To improve the combined gas production in coal measure strata,it is possible to simultaneously stimulate multiple coal seams or adjacent gas-bearing sandstones.In these cases,perforation location and length also significantly impact fracture propagation,and therefore should be carefully designed.Our simulation results using 3 D lattice algorithm are qualitatively consistent with laboratory physical simulation.3 D lattice models can be used to effectively simulate the fracture propagation through layers in coal measure strata.The numerical results provide guidance for perforation optimization in the hydraulic fracturing of coal measure strata.

Combined measures to control the COVID-19 pandemic in Wuhan, Hubei, China: A narrative review

Coronavirus disease 2019(COVID-19)is an emerging disease caused by the coronavirus,SARS-CoV-2,which leads to severe respiratory infections in humans.COVID-19 was first reported in December 2019 in Wuhan city,a populated area of the Hubei province in China.As of now,Wuhan and other cities nearby have become safe places for locals.The rapid control of the spread of COVID-19 infection was made possible due to several interventions and measures that were undertaken in Wuhan.This narrative review study was designed to evaluate the emerging literature on the combined measures taken to control the COVID-19 pandemic in Wuhan city.Science Direct,Springer,Web of Science,and the PubMed data repositories were searched for studies published between December 1,2019,and June 07,2020.The referred“preferred reporting items for systematic reviews and meta-analyses”(PRISMA)protocol was used to conduct this narrative review.A total of 330 research studies were found as a result of the initial search based on exclusion and inclusion criteria,and 30 articles were chosen on final evaluation.It was discovered that the combined measures to control the spread of COVID-19 in Wuhan included cordon sanitaire,social distancing,universal symptom surveys,quarantine strategies,and transport restrictions.Based on the recommendations presented in this review study,existing policies with regard to combined measures and public health policies can be enforced by other countries to implement a rapid control procedure to control the spread of the COVID-19 pandemic.

Meat Production Performances of Geese in Different Crossbred Combinations

[ Objective] To study the meat production performance of geese in different crossbred combination, and provide a reference for cultivating new multiplication strains of meat geese. [Method] A total of five goose breeds including Taihu goose （T）, Wulong goose （WL）, Wanxi white goose （WX）, Sichuan white goose （SC） and Sanhua goose （SH） were used as research objects, and eight crossbred combinations were designed. The body measurements, slaughter performance, conventional meat quality and muscle composition of 90-day-old geese in eight crossbred combinations were determined and comparatively analyzed. [ Result] All the body measurement indexes except thud width of WXSC combination were the biggest in the eight crossbred combinations. Contrarily, the body measurement indexes of SHSC combination, including average body weight, body slope length, breast depth, breast width, shank length, neck length and half-diving depth were the lowest in the eight crossbred combinations. The live weight, slaughter weight and abdomen fat weight of WXSC combinations ware 3 291.36, 2 956.46 and 77.84 g, respectively, which were the biggest in eight crossbred combinations. The slaughter rate of SHWL combinations was 92.96%, and more than other crossbred combinations. The shear force of SHT and WXWL combinations were the lowest （3.09 kg） and the highest （3.78 kg）, respectively. The water holding capacities of SCWL and WXSC combinations were the highest （66.46%） and the lowest （61.48%）, respectively. The percentage of moisture content of SHWL and SCT combinations were the highest （73.05%） and the lowest （66.77%）, respectively. The crude protein content of SHT and SHWL combinations were the highest （23.32%） and the lowest （21.94%）, respectively. The percentage of crude fat content of SHT and SCWL combinations were the highest （3.06%） and the lowest （1.67%）, respectively. [ Concusion] The growth rate of WXSC combination is the fastest, and the meat performance of SHT combination is the best.

基于上覆岩层应力场和裂缝场演化的采动井套管破断特征及防控对策

准确确定出煤矿采动井套管破断特征并提出相应的防控对策,能为井筒长期稳定提供重要保障。以平顶山矿区的二1煤层及上覆岩层为研究对象,采用理论计算与数值模拟软件模拟方法,确定出上覆岩层离层段应力和位移分布规律,分析了上覆岩层高度、距工作面水平距离与应力、位移的相关性,拟合出上覆岩层高度、距工作面水平距离与应力、位移的关系式;根据研究区采动井的实际开发经验,确定出最佳布井区域下的套管主要破断类型,结合常用套管力学参数,得出“两场”演化下的套管破断位置及长度等特征;对常用的采动井局部防护技术进行总结,并提出对应的防控对策。结果表明:工作面推进过程中,上覆岩层应力呈现出“波动-线性降低”的变化规律,位移呈现出“几乎未发生变化-类双曲线型”的变化规律。最佳布井区域下的采动井套管主要以拉伸缩径和剪切破断为主,选择施加套管加强件对采动井套管进行加固。研究区地面采动井三开段采用N80套管时,需在煤层上部46 m亚关键层处、54 m软硬互层处分别加设抗拉伸套管加强件和抗剪切加强件;采用P110套管时,需在煤层上部46 m亚关键层处加设抗拉伸加强件。建议研究区地面采动井三开段均采用P110套管,增加采动井的井筒稳定性。该研究成果为平顶山矿区及相似条件下采动井预防套管破断提供了理论指导。

天然气中硫化氢含量及硫同位素联测方法

我国含硫化氢天然气勘探潜力巨大,硫化氢成因、来源、形成机制为石油工作者所关注。硫化氢含量及硫同位素是两项常用且重要的判识指标。因硫化氢的强毒性,国内很多实验室较少检测或取消了此类检测项目。通过前处理流程优选硫化氢转化试剂,同时通过改进同位素质谱仪配套设备——调试硫同位素法拉第杯离子束聚焦等参数,安装特制色谱柱、特氟龙管路、硫反应管等,搭建了硫化氢含量及硫同位素联测技术平台;其次将高纯二氧化硫标准气替换为低浓度、低压力、小体积的工作标准气,通过系统条件实验探索(稳定性,标样分析等),确定最优实验条件;最后将反应生成的固体沉淀物送入质谱仪中进行硫同位素组成信息的检测,通过与标准纯含硫物质同位素组成的信号对比,计算出待测气体中硫化氢含量。用该方法对鄂尔多斯盆地大牛地气田、富县气田、鄂西渝东红星地区部分含硫化氢天然气进行硫化氢含量和硫同位素测试,所测结果稳定、精度良好,同时与外部实验室比对结果吻合。与传统方法比,该方法一次进样可得到硫含量和硫同位素数值;优选醋酸银试剂一步化学法一次性转化,减少同位素分馏;另一方面将硫化氢转化为固态硫化银,与标准物质硫化银硫同位素直接对比,同位素溯源结果更具可靠性;以低浓度、低压力、小体积的二氧化硫作为工作标准气,降低了实验室安全风险和仪器损害,满足环保安全需求。

基于交变磁场的平面二维时栅位移传感机理及测量模型

针对传统的平面二维位移传感器在超精密光刻、大面积传感器制造中存在的技术瓶颈,提出一种基于空间交变磁场的平面二维位移测量方法。在定尺平面布置均匀等间距的正弦/余弦激励绕组,施加时间正交激励电流,构建空间二维交变磁场,建立空间二维位移和时间基准的映射关系。通过“维度判断+位移解耦”的组合测量模型实现平面二维位移测量,利用动尺维度判断感应绕组阵列输出信号经二值化后的组合逻辑来判断维度;利用动尺两维差动布置的位移感应绕组阵列拾取交变磁场,得到空间位移行波信号,通过比相实现二维位移解耦。通过电磁仿真,对平面二维时栅位移测量模型进行误差分析。研制样机并搭建了实验平台,实验结果表明,传感器在120 mm×120 mm的有效测量范围内,X方向测量误差最大不超过±9.4μm,Y方向测量误差最大不超过±9.7μm,两维度位移测量分辨力为0.15μm。利用毫米级尺寸的激励和感应绕组实现平面二维微米级测量精度,从原理上突破了传统平面二维位移传感器对超精密光刻的制约,降低了传感器加工难度,具有重要的理论研究意义和工程应用价值。

多频率组合波形阵风场模拟与测量研究

基于数值模拟方法选取设定FL-51风洞阵风发生器的装置参数,如发生器叶片的数量、展长、弦长及间距等。发生器采用液压摆动缸独立驱动形式,可模拟正弦波、三角波及随机波等多种波形的多频率组合运动,同时能够减少安装传动件,并提升发生器性能。通过阵风场校测结果表明:叶片能够实现摆动频率为0 Hz~15 Hz,在校测范围内发生器产生的正弦流场较均匀;在来流风速40 m/s、叶片摆动频率为10 Hz、摆角为15°时,最大阵风幅值为8.5 m/s。地面测试与流场校测结果表明:该文所提出的阵风场模拟技术可以实现低速风洞多频率多波形组合运动,为风洞试验提供复杂的阵风流场。

支架固定馆藏人物俑文物的抗震优化设计研究

为优化支架固定馆藏人物俑文物的抗震效果,选取不同尺寸和体态的典型地震易损人物俑文物复制品(武士俑和唐三彩人物俑),开展文物复制品-优化组合措施(支架和卡固件)抗震系统振动台试验,获得影响文物复制品运动状态的关键优化参数、文物复制品与支架相互作用规律,并检验组合措施对较大体积人物俑文物的抗震固定效果。建立文物复制品-组合措施相互作用系统数值分析模型,通过参数分析,获得支架与文物间安装缝隙、在安装缝隙内填充不同种类隔震垫对文物动力响应的影响、文物复制品与固定措施相互作用规律及采用独立支架/组合措施有效固定人物俑的最小支架尺寸,为兼顾安全性及最小干预原则的固定措施优化设计提供必要依据。结果表明:相比独立支架,组合措施能够有效降低人物俑文物动力响应,有效提高固定效果;为保证人物俑文物安全,建议支架与文物间安装缝隙不大于5 mm;在缝隙中填充橡胶垫及硅胶垫可使文物与支架间相互作用力降低50%~75%,有效防止文物局部损伤;当人物俑文物体型超过一定限值,独立支架不再适用,建议选择支架和随形卡固件组合措施。

抽水蓄能电站防沙措施研究

以典型抽水蓄能电站为研究对象,开展了水库防沙措施研究。针对复杂工程条件,在分析各种防沙布置措施的基础上,考虑以沉代拦、导沉结合,提出导沙堤和尾水明渠相结合的防沙布置型式。经过数值模拟和物理模型验证,该型式减少过机泥沙效果明显,水力学参数合理。研究成果可为类似工程规划、设计和运行提供参考。

韧性城市建筑“平急结合”设计给排水应对关键措施探索

简介韧性城市建筑中适用于临时隔离收治点的建筑类型,提出建立临时隔离收治点“平急结合”设计的标准体系构想,解析作为临时隔离收治点的新建建筑、既有建筑在设计或改造中的给排水应对措施,重点就条件预留、用水定额、系统定型、管道布设、设备选用、污水处理等方面进行深入探索。

基于未确知测度方法的装配式建筑吊装风险研究

为实现对装配式建筑吊装风险的科学评价,基于AHP-熵组合赋权的未确知测度方法提出装配式建筑吊装风险量化评价方法。首先,遵循“4M1E”原则对风险因素进行梳理,从“人、物、技、环、管”5个方面对装配式建筑吊装风险因素进行识别,建立风险量化评价指标体系;然后,运用AHP计算评价指标主观权重,熵权法计算评价指标客观权重,结合最小熵原理计算组合权重,基于该权重与未确知测度方法提出装配式建筑吊装风险量化评价方法;最后,对湖南地区某装配式住宅项目进行实例研究。研究表明:该项目吊装总体风险判定为c4级(风险较小)。AHP-熵组合赋权未确知测度方法的可操作性较强,可用于装配式建筑吊装风险的量化评价。

某钨矿露地联采关键地压灾害监测预警研究

某钨矿形成了露地联采的开采局面,面临着井下群采空区与隔离间柱稳定性、露采边坡稳定性、露地相互影响等关键地压灾害问题。设计建设了最先进的66通道微震监测系统、测量机器人与边坡雷达等地压监测预警系统。文章详细介绍了一次典型的岩体失稳垮塌的成功预警案例。上述综合性的地压监测手段将为矿山安全生产提供重要的技术支撑。

面向多传感系统协同测量场的站位规划方法

针对大型构件多传感系统协同测量中各系统测量可达性模型多样化、多系统测量精度不均衡而导致的组合式测量站位设置多依赖测量人员经验以及需要不断尝试获取合适站位的问题,提出一种多传感系统协同测量场的站位规划方法。首先,考虑工装遮挡问题,对协同测量场中的组合式测量可达性模型进行优化,建立基于?鱼优化算法的有工装站位初值求解模型,解算组合式测量系统各测量站位初始值;其次,建立协同测量精度模型,以测量精度最佳为约束条件,建立观测值的加权均方根误差和矢量角度测量误差的优化目标函数,基于牛顿迭代算法不断迭代和更新到最佳精度站位坐标;最后,以某目标模拟器满足位置、姿态初始装调精度需求为例,进行组合式协同测量站位规划实验,优化后测量数据均方根误差为0.032 mm,相较于优化前测量规划位置测量精度提高34%,角度测量精度提高9.5%。该方法可有效地提高测量精度及可视化效果,为大型构件测量领域的进一步研究提供理论及应用参考。

堰槽组合设施水力特性试验与数值模拟

为探究堰槽组合设施的水力特性及适用性,通过模型试验与数值模拟相结合的方法,设计3组坡度(0.1%,0.4%,0.8%)、9组流量进行水力性能试验,验证了数值模拟对于堰槽组合的适用性,探究了不同底坡下堰槽组合装置的测流机制.结果表明:3组坡度阈值相对水深为0.880,0.930和0.873,测流公式精度较高,对应的平均误差分别为1.20%,1.69%和1.74%;不同坡度下,量水槽内水深沿程降低,中垂线平均流速沿程增加,流量小于阈值流量时,综合流量系数和中垂线平均流速随流量的增加而增大;流量大于阈值流量时,在过渡段上游1/3附近中垂线平均流速大小一致,流量系数和上游中垂线平均流速随流量的增大而减小,下游随流量的增大而增大;数值模拟结果最大误差为4.16%,与试验相吻合,数值模拟适用于堰槽组合量水设施的研究.