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The diagnostic value of liver stiffness measurement combined with S index in the degree of hepatitis B liver fibrosis
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作者 XU Bin SUN Long 《Journal of Hainan Medical University》 CAS 2023年第10期24-28,共5页
Objective:To investigate the value of liver stiffness measurement(LSM)combined with S index in predicting the degree of liver fibrosis in hepatitis B patients.Methods:A total of 187 chronic hepatitis B patients who we... Objective:To investigate the value of liver stiffness measurement(LSM)combined with S index in predicting the degree of liver fibrosis in hepatitis B patients.Methods:A total of 187 chronic hepatitis B patients who were admitted to the Department of Infection,the First Affiliated Hospital of Hainan Medical College from January 2019 to December 2021 were selected.General data were collected,blood routine,liver function,liver fibrosis and liver stiffness measurement were tested,and S index,APRI and FIB-4 index were calculated,and liver biopsy was performed.Results:According to the pathological results of liver puncture,The patients were divided into no significant fibrosis group(n=86),significant fibrosis group(n=71)and cirrhosis group(n=30).There were significant differences in age,PLT,GGT,ALB,S index,HA,LN and LSM levels among the three groups(P<0.05).There was a good correlation between S index and the degree of hepatic fibrosis(rs=0.738,P<0.001).The AUC of S index and LSM for the diagnosis of significant fibrosis in hepatitis B were 0.873 and 0.792,respectively.And the AUC of S index and LSM for the diagnosis of liver cirrhosis were 0.966 and 0.879,respectively.The AUC for the combined diagnosis of significant fibrosis and cirrhosis were 0.908 and 0.988,respectively.The AUROC of combined detection in the diagnosis of cirrhosis was higher than that of LSM,APRI and FIB-4(P<0.05).Conclusion:LSM combined with S index has certain application value in the diagnosis of liver fibrosis/cirrhosis in hepatitis B patients. 展开更多
关键词 Liver fibrosis Tliver stiffness measurement s index
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Optimization model of unascertained measurement for underground mining method selection and its application 被引量:6
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作者 刘爱华 董蕾 董陇军 《Journal of Central South University》 SCIE EI CAS 2010年第4期744-749,共6页
An optimization model of underground mining method selection was established on the basis of the unascertained measurement theory.Considering the geologic conditions,technology,economy and safety production,ten main f... An optimization model of underground mining method selection was established on the basis of the unascertained measurement theory.Considering the geologic conditions,technology,economy and safety production,ten main factors influencing the selection of mining method were taken into account,and the comprehensive evaluation index system of mining method selection was constructed.The unascertained evaluation indices corresponding to the selected factors for the actual situation were solved both qualitatively and quantitatively.New measurement standards were constructed.Then,the unascertained measurement function of each evaluation index was established.The index weights of the factors were calculated by entropy theory,and credible degree recognition criteria were established according to the unascertained measurement theory.The results of mining method evaluation were obtained using the credible degree criteria,thus the best underground mining method was determined.Furthermore,this model was employed for the comprehensive evaluation and selection of the chosen standard mining methods in Xinli Gold Mine in Sanshandao of China.The results show that the relative superiority degrees of mining methods can be calculated using the unascertained measurement optimization model,so the optimal method can be easily determined.Meanwhile,the proposed method can take into account large amount of uncertain information in mining method selection,which can provide an effective way for selecting the optimal underground mining method. 展开更多
关键词 地下采矿方法 未确知测度模型 优化模型 综合评价指标体系 采矿方法选择 信息熵理论 应用 测度理论
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Blasting cumulative damage effects of underground engineering rock mass based on sonic wave measurement 被引量:5
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作者 闫长斌 《Journal of Central South University of Technology》 EI 2007年第2期230-235,共6页
The principle of sonic wave measurement was introduced, and cumulative damage effects of underground engineering rock mass under blasting load were studied by in situ test, using RSM-SY5 intelligent sonic wave apparat... The principle of sonic wave measurement was introduced, and cumulative damage effects of underground engineering rock mass under blasting load were studied by in situ test, using RSM-SY5 intelligent sonic wave apparatus. The blasting test was carried out for ten times at some tunnels of Changba Lead-Zinc Mine. The damage depth of surrounding rock caused by old blasting excavation (0.8-1.2 m) was confirmed. The relation between the cumulative damage degree and blast times was obtained. The results show that the sonic velocity decreases gradually with increasing blast times, but the damage degree (D) increases. The damage cumulative law is non-linear. The damage degree caused by blast decreases with increasing distance, and damage effects become indistinct. The blasting damage of rock mass is anisotropic. The damage degree of rock mass within charging range is maximal. And the more the charge is, the more severe the damage degree of rock mass is. The test results provide references for researches of mechanical parameters of rock mass and dynamic stability analysis of underground chambers. 展开更多
关键词 地下工程 岩体 爆破 累积损坏效应 声波测量 围岩
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PROGRESS OF ACOUSTIC WAVE TECHNIQUE ANDITS APPLICATION IN UNDERGROUND PRESSURE MEASUREMENT
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作者 周楚良 李新元 张晓龙 《Journal of China University of Mining and Technology》 1994年第1期80-91,共12页
This paper carries out tbe experirnent study on the correlation between am stress-strain process of rock samples and the acoustie parameter change of rock by using the measurement system of KS acoustic wave data proce... This paper carries out tbe experirnent study on the correlation between am stress-strain process of rock samples and the acoustie parameter change of rock by using the measurement system of KS acoustic wave data processing device. On the spot, the stability of surrounding rock is studied by means of experiments on the relationship between the change process (from elastie to plastic failure zone) in surrounding rock of roadway and the change law of acoustic parameters of rock. These acoustie parameters inelude wave amplitude, spectral amplitude, spectrum area, spectral density,wave veloeity and attenuation coefficient etc. 展开更多
关键词 矿山压力 物理性质 稳定性研究 应力波 超声波谱法 实测技术
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基于WSN和TJ_UWIS的地下结构变形动态监测平台与教学应用
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作者 张冬梅 韩星 +2 位作者 黄忠凯 冯永珍 马旭 《实验技术与管理》 CAS 北大核心 2024年第6期206-212,共7页
为实现复杂条件下地下结构变形的动态监测,提高学生对无线监测系统的认知,设计了基于WSN(wireless sensor network)和TJ_UWIS倾角传感支点的无线监测实验平台,并应用于实际教学中。该实验平台测量精度高,可以通过TJ_UWIS倾角传感支点测... 为实现复杂条件下地下结构变形的动态监测,提高学生对无线监测系统的认知,设计了基于WSN(wireless sensor network)和TJ_UWIS倾角传感支点的无线监测实验平台,并应用于实际教学中。该实验平台测量精度高,可以通过TJ_UWIS倾角传感支点测得地下结构的X/Y/Z三向的倾角变形值,从而反映结构的实际变形状况;最大监测频率可设置为1 min/次,可实现结构变形的精准动态监测。该实验平台的应用,有助于提高学生对无线传感监测系统原理与系统组成的认识,掌握具体应用方法,锻炼学生的专业素养和创新思维。 展开更多
关键词 无线监测 倾角传感器 地下结构变形 实验测量平台
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Tracking a maneuvering target in clutter with out-of-sequence measurements for airborne radar 被引量:3
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作者 Weihua Wu Jing Jiang Yang Wan 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2015年第4期746-753,共8页
There are many proposed optimal or suboptimal al- gorithms to update out-of-sequence measurement(s) (OoSM(s)) for linear-Gaussian systems, but few algorithms are dedicated to track a maneuvering target in clutte... There are many proposed optimal or suboptimal al- gorithms to update out-of-sequence measurement(s) (OoSM(s)) for linear-Gaussian systems, but few algorithms are dedicated to track a maneuvering target in clutter by using OoSMs. In order to address the nonlinear OoSMs obtained by the airborne radar located on a moving platform from a maneuvering target in clut- ter, an interacting multiple model probabilistic data association (IMMPDA) algorithm with the OoSM is developed. To be practical, the algorithm is based on the Earth-centered Earth-fixed (ECEF) coordinate system where it considers the effect of the platform's attitude and the curvature of the Earth. The proposed method is validated through the Monte Carlo test compared with the perfor- mance of the standard IMMPDA algorithm ignoring the OoSM, and the conclusions show that using the OoSM can improve the track- ing performance, and the shorter the lag step is, the greater degree the performance is improved, but when the lag step is large, the performance is not improved any more by using the OoSM, which can provide some references for engineering application. 展开更多
关键词 out-of-sequence measurements (OosM(s)) Earth-centered Earth-fixed (ECEF) interacting multiple model (IMM) probabilistic data association (PDA) attitude.
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Problems of durability and reinforcement measures for underground structures in China 被引量:1
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作者 Xianming Zeng Zhenyu Wang +3 位作者 Junqi Fan Lin Zhao Dalu Lin Jian Zhao 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE 2011年第3期250-259,共10页
In this paper, the bolt- and cable-supported structures mainly refer to anchored cables, anchored bolts, soil nails and other commonly used reinforcing and supporting structures in geotechnical engineering, as well as... In this paper, the bolt- and cable-supported structures mainly refer to anchored cables, anchored bolts, soil nails and other commonly used reinforcing and supporting structures in geotechnical engineering, as well as reinforced soil structures in permanent works. They are often used in combination, or formed into composite bolt-and cable-supported structures, with other traditional construction methods and relevant measures. Distinct characteristics of such structures are that they are most often invisible, exposed to more severe underground corrosive environments and with strict durability requirements. A number of serious durability problems of underground structures are discussed and major achievements and advances in China and abroad in terms of durability and reinforcement measures for underground structures are reviewed, followed by comprehensive analyses. Some suggestions for those problems are put forward. 展开更多
关键词 underground structures DURABILITY service life reinforcement measures
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基于TDLAS的H_(2)S气体材料表面吸附特性研究
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作者 金建新 刘威 +3 位作者 宋振明 朱志辉 田冰 彭志敏 《激光与红外》 CAS CSCD 北大核心 2024年第5期710-717,共8页
在H_(2)S气体浓度在线监测过程中,因其具有粘附性强的特点,容易发生管线吸附,从而导致测量结果存在偏差,尤其在痕量H_(2)S检测过程中表现最为明显,所以开展H_(2)S气体管线材料表面吸附特性研究尤为必要。本文基于可调谐二极管激光吸收... 在H_(2)S气体浓度在线监测过程中,因其具有粘附性强的特点,容易发生管线吸附,从而导致测量结果存在偏差,尤其在痕量H_(2)S检测过程中表现最为明显,所以开展H_(2)S气体管线材料表面吸附特性研究尤为必要。本文基于可调谐二极管激光吸收光谱技术(TDLAS),设计并搭建了一套H_(2)S浓度在线测定系统,并对该系统进行了测量性能检验,在此基础上进行了H_(2)S在不锈钢材料表面常温吸附特性探究。实验结果表明,所搭建H_(2)S浓度在线测定系统具有稳定性强、检测限低和灵敏度高的特点,利用此系统可以实现痕量H_(2)S浓度的在线连续测定。经过一系列探究试验,证明了H_(2)S在不锈钢材料表面存在明显且稳定的吸附作用,得出了H_(2)S在不锈钢材料表面的单位面积吸附量在10^(14)(个/cm^(2))量级。实验结果可以为痕量硫化氢在线精准测量提供一定参考。 展开更多
关键词 TDLAs H_(2)s 测量系统 材料表面 吸附特性
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S型皮托管对向和非对向测量方法准确度实验研究
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作者 张乐垚 张亮 +3 位作者 郭素娜 郭虎林 鲁贵祥 孔令彩 《计量学报》 CSCD 北大核心 2024年第6期864-872,共9页
S型皮托管的对向和非对向测量方法准确度在不同工况下有较大差异。通过风洞实流实验对风速、流速攻角和结构参数对S型皮托管对向和非对向测量方法准确度的影响进行了研究。结果表明:风速由5 m/s变化至30 m/s时,在不同流速攻角下S型皮托... S型皮托管的对向和非对向测量方法准确度在不同工况下有较大差异。通过风洞实流实验对风速、流速攻角和结构参数对S型皮托管对向和非对向测量方法准确度的影响进行了研究。结果表明:风速由5 m/s变化至30 m/s时,在不同流速攻角下S型皮托管对向和非对向测量准确度最大差异超过10%;对向和非对向测量中静压孔的压力变化是皮托管在较大流速攻角下造成测量误差的主因;外径较小、总静压孔距较大、测量端弯曲角度在15°至30°间、取压孔内径更小的S型皮托管在对向和非对向测量中都有更高的测量准确度;俯仰角取正值时对向测量准确度全面优于非对向测量,在俯仰角和偏航角同为45°时测量准确度差异达到最大值,大于70%。 展开更多
关键词 流量测量 s型皮托管 烟道流量 对向测量 非对向测量 测量准确度
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Measurement of mouse liver glutathione S-transferase activity by the integrated method 被引量:10
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作者 廖飞 李甲初 +2 位作者 康格非 曾昭淳 左渝萍 《Journal of Medical Colleges of PLA(China)》 CAS 2003年第5期295-300,共6页
Objective: The integrated method was investigated to measure Vm/Km of mouse liver glutathione S-transferase (GST) activity on GSH and 7-Cl-4-nitrobenzofurazozan. Methods: Presetting concentration of one substrate twen... Objective: The integrated method was investigated to measure Vm/Km of mouse liver glutathione S-transferase (GST) activity on GSH and 7-Cl-4-nitrobenzofurazozan. Methods: Presetting concentration of one substrate twenty-fold above the others and taking maximum product absorbance Am as parameter while Km as constant, Vm/Km was obtained by nonlinear fitting of GST reaction curve to the integrated Michaelis-Menten equation ln [Am/(Am-Ai)]+Ai/(ε×Km)=(Vm/Km)×ti (1). Results: Vm/Km for GST showed slight dependence on initial substrate concentration and data range, but it was resistant to background absorbance, error in reaction origin and small deviation in presetting Km. Vm/Km was proportional to the amount of GST with upper limit higher than that by initial rate. There was close correlation between Vm/Km and initial rate of the same GST. Consistent results were obtained by this integrated method and classical initial rate method for the measurement of mouse liver GST. Conclusion: With the concentration of one substrate twenty-fold above the others, this integrated method was reliable to measure the activity of enzyme on two substrates, and substrate concentration of the lower one close to its apparent Km was able to be used. 展开更多
关键词 肝脏 谷胱甘肽s-转移酶 VM KM
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基于TDLAS的H_(2)S高温反应特性实验研究
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作者 王嘉琦 田思迪 +3 位作者 高东波 田志伟 彭志敏 杜艳君 《热力发电》 CAS CSCD 北大核心 2024年第2期162-169,共8页
电站锅炉在低NO_(x)燃烧过程中因锅炉内还原性气氛浓度较高,会产生较多H_(2)S气体。针对H_(2)S因具有易燃、强腐蚀性、剧毒性而可能对火电厂造成多种危害的问题,采用可调谐二极管激光吸收光谱(tunable diode laser absorption spectrosc... 电站锅炉在低NO_(x)燃烧过程中因锅炉内还原性气氛浓度较高,会产生较多H_(2)S气体。针对H_(2)S因具有易燃、强腐蚀性、剧毒性而可能对火电厂造成多种危害的问题,采用可调谐二极管激光吸收光谱(tunable diode laser absorption spectroscopy,TDLAS)方法结合多通池和计算机搭建低气体摩尔分数在线测量系统,实现了对混合气体中摩尔分数在10–6量级H_(2)S的精确在线测量,并利用该测量系统进行了H_(2)S高温反应实验,探究实验温度和混合气体中O_(2)摩尔分数对该反应的影响。实验结果展示了压力为80 kPa、O_(2)摩尔分数为0~5%的条件下,H_(2)S开始发生化学反应的温度随O_(2)摩尔分数变化的变化规律,整体而言,混合气体中O_(2)摩尔分数越高,H_(2)S开始发生化学反应的温度越低。实验结果可以为锅炉烟气中H_(2)S的生成、转化和危害控制提供一定数据基础。 展开更多
关键词 TDLAs H_(2)s 在线测量 高温反应 O_(2)摩尔分数
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不同中医证型Wilson病患者肝脏纤维化差异及其与弹性硬度值的关系
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作者 吴晓倩 唐露露 +2 位作者 王金萍 李冰 王艺星 《中西医结合肝病杂志》 CAS 2024年第6期495-499,共5页
目的:探讨不同中医证型Wilson病(WD)患者肝脏硬度值(LSM)及纤维化指标差异及两者的关系。方法:回顾性收集2021年2月至2023年4月住院确诊的110例WD患者的临床资料,中医证型采用指标聚类分析,绘制聚类图。采用简单对应分析中医证型与ADL... 目的:探讨不同中医证型Wilson病(WD)患者肝脏硬度值(LSM)及纤维化指标差异及两者的关系。方法:回顾性收集2021年2月至2023年4月住院确诊的110例WD患者的临床资料,中医证型采用指标聚类分析,绘制聚类图。采用简单对应分析中医证型与ADL分级的相关性。比较不同中医证型的一般临床资料、LSM及肝纤维化相关指标,从而探讨LSM与肝纤维化及中医证型分布的关系。结果:WD患者中医证型以湿热内蕴证(59例,53.64%)居多,痰瘀互结证(43例,39.09%)次之,肝肾阴虚证(5例,4.54%)、脾肾阳虚证(3例,2.73%)较少;痰瘀互结证偏向0~Ⅰ级,湿热内蕴证偏向Ⅱ级,肝肾阴虚证偏向Ⅲ~Ⅳ级,脾肾阳虚证在二维投影图中间,并未偏向WD病变程度某一分级;痰瘀互结证、肝肾阴虚证、脾肾阳虚证患者肝脏LSM均高于湿热内蕴证(P<0.05);肝肾阴虚证、脾肾阳虚证患者血清透明质酸(HA)和Ⅳ型胶原(Ⅳ-C)水平高于湿热内蕴证、痰瘀互结证组(P<0.05),4组患者Ⅲ型前胶原氨基端肽(PⅢNP)、层黏连蛋白(LN)水平差异无统计学意义(P>0.05)。湿热内蕴证、痰瘀互结证、肝肾阴虚证中LSM与HA、Ⅳ-C均呈不同程度的正相关。结论:LSM联合血清学指标能更好地评估不同证型WD患者肝纤维化程度。 展开更多
关键词 WILsON病 中医证型 肝脏硬度值 肝纤维化
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基于激光吸收光谱的CO/CO_(2)/H_(2)S浓度同步在线测量研究
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作者 张学军 陈勤根 +3 位作者 杨展 邓琴 贺拴玲 彭志敏 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2024年第5期1412-1416,共5页
CO、CO_(2)、H_(2)S是燃煤锅炉炉内气氛重要组成部分,其浓度不仅能够反映燃烧工况,还可作为水冷壁高温腐蚀程度判断依据,因此实现CO、CO_(2)、H_(2)S浓度的准确测量意义重大。首先采用波长调制-直接吸收(WM-DAS)方法结合约40 m长光程Her... CO、CO_(2)、H_(2)S是燃煤锅炉炉内气氛重要组成部分,其浓度不仅能够反映燃烧工况,还可作为水冷壁高温腐蚀程度判断依据,因此实现CO、CO_(2)、H_(2)S浓度的准确测量意义重大。首先采用波长调制-直接吸收(WM-DAS)方法结合约40 m长光程Herriott池,在室温低压下,开展不同CO/CO_(2)浓度配比下三种气体吸收率同步测量实验,结果表明三种气体的吸收率测量值与理论计算值相近,相对误差在6.82%以内,测量结果可靠性较高;然后对不同浓度CO/CO_(2)(0~2000μL·L^(-1))、H_(2)S(0~20μL·L^(-1))进行动态测量,结果表明,测量系统对三种组分浓度变化的响应具有较好的线性度。 展开更多
关键词 波长调制-直接吸收光谱 CO浓度 CO_(2)浓度 H_(2)s浓度 同步测量
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Simultaneous measurements of aeroacoustic sounds and wall vibration for exploring the contribution of tooth vibration in the production of sibilant sounds/s/
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作者 Masanori Nakamura Kazunori Nozaki +3 位作者 Haruka Takimoto Kazuya Nagamune Motoharu Fujigaki Shigeo Wada 《Journal of Biomedical Science and Engineering》 2011年第2期83-89,共7页
In order to understand the contribution of teeth vibration to the production of sibilant/s/, the pre-sent study was designed to develop a method of simultaneously measuring aeroacoustic sounds and the vibration of an ... In order to understand the contribution of teeth vibration to the production of sibilant/s/, the pre-sent study was designed to develop a method of simultaneously measuring aeroacoustic sounds and the vibration of an obstacle. To measure the vibration without disturbing flow, the Michelson interferometer was employed. The flow channel, which had an obstacle wall inside of it, was fabricated such that it morphologically mimicked the simplified geometry of the oral cavity. Given airflows at a flow rate of 7.5 × 10–4 m3/s from the inlet, aeroacoustic sounds were generated. A spectrum analy-sis of the data demonstrated two prominent peaks in the sound at 1,300 and 3,500 Hz and one peak in the wall vibration at 3,500 Hz. The correlation in peak frequencies between the sound and wall vibration suggests that the sound at 3,500 Hz was induced by the wall vibration. In fact, the sound amplitude at 3,500 Hz decreased when the obstacle wall was thickened, which increased its rigidity (p < 0.05, t-test). The experimental results demonstrate that the developed techniques are capable of measuring aeroacoustic sound and obstacle wall vibration simultaneously, and suggest the potential to pave the way for detailed analysis of the production of sibilant sounds /s/. 展开更多
关键词 Acoustic measurement VIBRATION measurement Michelson INTERFEROMETER Aeroacoustics sibilant/s/
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Online dynamic measurement of saturation-capillary pressure relation in sandy medium under water level fluctuation 被引量:1
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作者 李雁 周劲风 +1 位作者 徐军 KAMON M 《Journal of Central South University》 SCIE EI CAS 2010年第1期85-92,共8页
An online dynamic method based on electrical conductivity probe, tensiometer and datataker was presented to measure saturation-capillary pressure (S-p) relation in water-light nonaqueous phase liquid (LNAPL) two-phase... An online dynamic method based on electrical conductivity probe, tensiometer and datataker was presented to measure saturation-capillary pressure (S-p) relation in water-light nonaqueous phase liquid (LNAPL) two-phase sandy medium under water level fluctuation. Three-electrode electrical conductivity probe (ECP) was used to measure water saturation. Hydrophobic tensiometer was obtained by spraying waterproof material to the ceramic cup of commercially available hydrophilic tensiometer. A couple of hydrophilic tensiometer and hydrophobic tensiometer were used to measure pore water pressure and pore LNAPL pressure of the sandy medium, respectively. All the signals from ECP and tensiometer were collected by a data taker connected with a computer. The results show that this method can finish the measurement of S-p relation of a complete drainage or imbibition process in less than 60 min. It is much more timesaving compared with 10-40 d of traditional methods. Two cycles of water level fluctuation were produced, and four saturation-capillary pressure relations including two stable residual LNAPL saturations of the sandy medium were obtained during in 350 h. The results show that this method has a good durable performance and feasibility in the porous medium with complicated multiphase flow. Although further studies are needed on the signal stability and accuracy drift of the ECP, this online dynamic method can be used successfully in the rapid characterization of a LNAPL migration in porous media. 展开更多
关键词 水位波动 动态测量 孔隙压力 饱和度 毛细管 LNAPL 表面张力 动态方法
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Data from Twenty-Three FRB’s Confirm the Universe Is Static and Not Expanding
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作者 Lyndon Errol Ashmore 《Journal of High Energy Physics, Gravitation and Cosmology》 CAS 2024年第3期1152-1177,共26页
Fast Radio Bursts from far away galaxies have travelled through the IGM and provide a tool to study its composition. Presently there are 23 FRB’s whose host galaxies have been identified and the redshift found. This ... Fast Radio Bursts from far away galaxies have travelled through the IGM and provide a tool to study its composition. Presently there are 23 FRB’s whose host galaxies have been identified and the redshift found. This gives us the opportunity to test Dispersion Measure versus redshift predictions made by two models. The Macquart relation for an expanding Universe and the New Tired Light relationship in a static universe. In New Tired Light, redshifts are produced when a photon is absorbed and re-emitted by the electrons in the IGM which recoil on both occasions. Some of the energy of the photon has been transferred to the kinetic energy of the recoiling electron. The photon has less energy, a lower frequency and a longer wavelength. It has been redshifted. Since dispersion is due to an interaction between radio signals and these same electrons one would expect a direct relationship between DM and redshift in the New Tired light model. The relation is DM=(mec/2hre)ln(1+z)and contains no adjustable parameters—just a combination of universal constants related to the electron and photon. Notice that the relation is independent of the electron number density ne since a change in ne affects both the DM and redshift equally. A graph of DM versus ln(1 + z) will be a straight line of gradient (mec/2hre)and, using SI units, substituting for the constants gives 7.318 × 1025 m−2. Using the data from the 23 well localized FRB’s, with the weighting of the DM’s for expansion removed (so that the data corresponds to a static universe), a graph of DM versus ln(1 + z) has a gradient of 6.7 × 1025 m−2—9% below the predicted (mec/2hre). The Macquart relation involves highly processed data and adjustable parameters to allow for “dark energy” and “dark matter” (neither of which has yet been found) and can be reduced to DM = 850z (in units of pc∙cm−3). Using the data from this set of localized FRB’s gives a trendline with gradient 1.10 × 103 pc∙cm−3—almost 30% higher than that predicted in an expanding universe model. The FRB data clearly comes down in favour of a static universe rather than an expanding one. Combining the DM-z relationship for the 23 well localized FRB’s, with the Hubble diagram, drawn using the NED-D compilation of redshift independent extragalactic distances, produces a value of “ne” the mean electron number density of the IGM, of ne=0.48 m−3close to the value ne=0.5 m−3, long since predicted by NTL. 展开更多
关键词 REDsHIFT Dispersion measure Fast Radio Bursts FRB’s Tired Light static Universe IGM
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Precision Frequency Measurement of ^(87)Rb 5S_(1/2)(F=2)→5D_(5/2)(F″=4)Two-Photon Transition through a Fiber-Based Optical Frequency Comb
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作者 夏巍 戴少阳 +3 位作者 张胤 李坤乾 于齐 陈徐宗 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第5期30-34,共5页
The absolute frequency of 87Rb 5S1/2 (F=2)→5D5/2 (F" = 4) two-photon transition at 778nm is measured in an accuracy of 44kHz. A home-made erbium-doped fiber laser frequency comb with frequency stability of 5.0 ... The absolute frequency of 87Rb 5S1/2 (F=2)→5D5/2 (F" = 4) two-photon transition at 778nm is measured in an accuracy of 44kHz. A home-made erbium-doped fiber laser frequency comb with frequency stability of 5.0 × 10-13@1 s is employed for the light source. By using a periodically poled lithium niobate, the femtosecond pulse operating in 1556 nm is frequency-doubled to 778 nm to obtain the direct two-photon transition spectroscopy of thermal rubidium vapor. Through sweeping the carrier envelope offset frequency (fceo), the 5S1/2 (F=2)→5D5/2 (F" = 4) two-photon transition line is clearly resolved and its absolute frequency is determined via the peak-finding of the fitting curve. After the frequency correction, the measured result agrees well with the previous experiment on this transition. The entire potential candidate of optical frequency standard for system configuration is compact and robust, providing a telecommunication applications. 展开更多
关键词 Precision Frequency measurement of in is F=2 on as been Rb 5s F Two-Photon Transition through a Fiber-Based Optical Frequency Comb
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基于SLAM(即时定位与地图构建)技术的三维激光扫描测量方法
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作者 季杰 邵华 《城市轨道交通研究》 北大核心 2024年第S01期97-102,共6页
[目的]为解决传统测量方式在城市轨道交通地下车站测量中的困难,提出了基于SLAM(即时定位与地图构建)技术的三维激光扫描测量方法。[方法]介绍了SLAM技术,以及基于该技术的外业作业流程和内业数据处理流程;结合上海游泳馆和某地铁站测... [目的]为解决传统测量方式在城市轨道交通地下车站测量中的困难,提出了基于SLAM(即时定位与地图构建)技术的三维激光扫描测量方法。[方法]介绍了SLAM技术,以及基于该技术的外业作业流程和内业数据处理流程;结合上海游泳馆和某地铁站测量项目,介绍了基于SLAM技术的三维激光扫描测量方法的应用效果。[结果及结论]该测量方法设备便携,测量精度高,可以避免在地下测量中信号丢失,可用于复杂的地下空间测量,测量数据可与CAD等制图软件结合应用,目前已在城市轨道交通地下车站测量中得到广泛应用。 展开更多
关键词 城市轨道交通 地下车站 sLAM技术 扫描测量
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Von Neumann’s Theory, Projective Measurement, and Quantum Computation
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作者 Koji Nagata Tadao Nakamura 《Journal of Applied Mathematics and Physics》 2015年第7期874-897,共24页
We discuss the fact that there is a crucial contradiction within Von Neumann’s theory. We derive a proposition concerning a quantum expected value under an assumption of the existence of the orientation of reference ... We discuss the fact that there is a crucial contradiction within Von Neumann’s theory. We derive a proposition concerning a quantum expected value under an assumption of the existence of the orientation of reference frames in N spin-1/2 systems (1 ≤ N to a new constant . It may be said that a new type of the quantum theory early approaches Newton’s theory in the macroscopic scale than the old quantum theory does. We discuss how our solution is used in an implementation of Deutsch’s algorithm. 展开更多
关键词 Von Neumann’s THEORY PROJECTIVE measurement and QUANTUM COMPUTATION
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Schrödinger’s Cat Paradox Resolution Using GRW Collapse Model: Von Neumann Measurement Postulate Revisited
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作者 Jaykov Foukzon Alex Potapov +1 位作者 Elena Men’kova Stanislav Podosenov 《Journal of Applied Mathematics and Physics》 2017年第2期494-521,共28页
In his famous thought experiment, Schr?dinger (1935) imagined a cat that measures the value of a quantum mechanical observable with its life. Since Schr?dinger’s time, no any interpretations or modifications of quant... In his famous thought experiment, Schr?dinger (1935) imagined a cat that measures the value of a quantum mechanical observable with its life. Since Schr?dinger’s time, no any interpretations or modifications of quantum mechanics have been proposed which give clear unambiguous answers to the questions posed by Schr?dinger’s cat of how long superpositions last and when (or whether) they collapse? In this paper appropriate modification of quantum mechanics is proposed. We claim that canonical interpretation of the wave function is correct only when the supports of the wave functions and essentially overlap. When the wave functions and have separated supports (as in the case of the experiment that we are considering in this paper) we claim that canonical interpretation of the wave function is no longer valid for a such cat state. Possible solution of the Schr?dinger’s cat paradox is considered. We pointed out that the collapsed state of the cat always shows definite and predictable outcomes even if cat also consists of a superposition: . 展开更多
关键词 Probability Representation of Quantum states schrödinger’s CAT GRW COLLAPsE MODEL Von NEUMANN measurement Postulate
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