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Combination of terrestrial reference frames based on space geodetic techniques in SHAO:methodology and main issues 被引量:2
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作者 Bing He Xiao-Ya Wang +1 位作者 Xiao-Gong Hu Qun-He Zhao 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2017年第9期1-14,共14页
Based on years of input from the four geodetic techniques (SLR, GPS, VLBI and DORIS), the strategies of the combination were studied in SHAO to generate a new global terrestrial reference frame as the material reali... Based on years of input from the four geodetic techniques (SLR, GPS, VLBI and DORIS), the strategies of the combination were studied in SHAO to generate a new global terrestrial reference frame as the material realization of the ITRS defined in IERS Conventions. The main input includes the time series of weekly solutions (or fortnightly for SLR 1983-1993) of observational data for satellite techniques and session-wise normal equations for VLBI. The set of estimated unknowns includes 3- dimensional Cartesian coordinates at the reference epoch 2005.0 of the stations distributed globally and their rates as well as the time series of consistent Earth Orientation Parameters (EOPs) at the same epochs as the input. Besides the final solution, namely SOL-2, generated by using all the inputs before 2015.0 obtained from short-term observation processing, another reference solution, namely SOL- 1, was also computed by using the input before 2009.0 based on the same combination of procedures for the purpose of comparison with ITRF2008 and DTRF2008 and for evaluating the effect of the latest six more years of data on the combined results. The estimated accuracy of the x-component and y-component of the SOL- 1 TRF-origin was better than 0.1 mm at epoch 2005.0 and better than 0.3 mm yr- 1 in time evolution, either compared with ITRF2008 or DTRF2008. However, the z-component of the translation parameters from SOL-1 to ITRF2008 and DTRF2008 were 3.4 mm and -1.0 ram, respectively. It seems that the z-component of the SOL-1 TRF-origin was much closer to the one in DTRF2008 than the one in ITRF2008. The translation parameters from SOL-2 to ITRF2014 were 2.2, -1.8 and 0.9 mm in the x-, y- and z-components respectively with rates smaller than 0.4 mmyr-1. Similarly, the scale factor transformed from SOL-1 to DTRF2008 was much smaller than that to ITRF2008. The scale parameter from SOL-2 to ITRF2014 was -0.31 ppb with a rate lower than 0.01 ppb yr-1. The external precision (WRMS) compared with IERS EOP 08 C04 of the combined EOP series was smaller than 0.06 mas for the polar motions, smaller than 0.01 ms for the UT1-UTC and smaller than 0.02 ms for the LODs. The precision of the EOPs in SOL-2 was slightly higher than that of SOL-1. 展开更多
关键词 astrometry w reference systems -- techniques: interferometers -- methods: data analysis
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Fiber Bragg Grating Sensor Array System Based on Digital Phase Generated Carrier Demodulation and Reference Compensation Method 被引量:2
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作者 Jun He Fang Li Hao Xiao Yu-Liang Liu 《Journal of Electronic Science and Technology of China》 2008年第4期389-392,共4页
A novel fiber Bragg grating (FBG) sensor array system based on digital phase generated carrier (PGC) demodulation and reference compensation method is proposed and set up. Experimental results confirm that the dig... A novel fiber Bragg grating (FBG) sensor array system based on digital phase generated carrier (PGC) demodulation and reference compensation method is proposed and set up. Experimental results confirm that the digital PGC demodulation can be used for wavelength-division-multiplexed FBG sensor array and the reference compensation method can reduce the environmental interference by approximately 40 dB in the frequency range from 20 Hz to 2 kHz. The minimum detectable wavelength-shift of the sensor system is 1 × 10^-3 pm/Hz^1/2. 展开更多
关键词 Fiber Bragg grating (FBG) sensor phase generated carrier (PGC) reference compensation method wavelength division multiplexing.
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Comparison of Methods for Estimating Reference Crop Evapotranspiration in Beijing 被引量:1
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作者 Cao Yajie Shi Youyu +1 位作者 Mo Nannan Li Xin 《Meteorological and Environmental Research》 CAS 2019年第6期72-74,78,共4页
Based on the meteorological data from 1951 to 2015 in Beijing,the reference crop evapotranspiration(ET_0)in Beijing was estimated using the FAO 56 Penman-Monteith method,the FAO PPP-17 Penman method,the Hargreaves met... Based on the meteorological data from 1951 to 2015 in Beijing,the reference crop evapotranspiration(ET_0)in Beijing was estimated using the FAO 56 Penman-Monteith method,the FAO PPP-17 Penman method,the Hargreaves method,and the Priestley-Taylor method.The results showed that the monthly and annual changing trends of ET0 estimated by the four methods are basically the same.In general,the ET0 values estimated by the Hargreaves method are the closest to those of the standard method FAO 56 Penman-Monteith,while the difference between the FAO PPP-17 Penman method and the standard method is the biggest.The Hargreaves method is the most suitable method for the estimation of ET0 in Beijing. 展开更多
关键词 referENCE CROP EVAPOTRANSPIRATION ESTIMATION method Comparison
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Comparison study on measurement of rail weld joint between inertial reference method and multi-point chord reference method
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作者 Yifan Shi Yuan Wang +1 位作者 Xiaozhou Liu Ping Wang 《Railway Sciences》 2024年第1期69-83,共15页
Purpose – Straightness measurement of rail weld joint is of essential importance to railway maintenance. Dueto the lack of efficient measurement equipment, there has been limited in-depth research on rail weld joint ... Purpose – Straightness measurement of rail weld joint is of essential importance to railway maintenance. Dueto the lack of efficient measurement equipment, there has been limited in-depth research on rail weld joint with a5-m wavelength range, leaving a significant knowledge gap in this field.Design/methodology/approach – In this study, the authors used the well-established inertial referencemethod (IR-method), and the state-of-the-art multi-point chord reference method (MCR-method). Two methodshave been applied in different types of rail straightness measurement trollies, respectively. These instrumentswere tested in a high-speed rail section within a certain region of China. The test results were ultimatelyvalidated through using traditional straightedge and feeler gauge methods as reference data to evaluate the railweld joint straightness within the 5-m wavelength range.Findings – The research reveals that IR-method and MCR-method produce reasonably similar measurementresults for wavelengths below 1 m. However, MCR-method outperforms IR-method in terms of accuracy forwavelengths exceeding 3 m. Furthermore, it was observed that IR-method, while operating at a slower speed,carries the risk of derailing and is incapable of detecting rail weld joints and low joints within the track.Originality/value – The research compare two methods’ measurement effects in a longer wavelength rangeand demonstrate the superiority of MCR-method. 展开更多
关键词 Rail weld joint Inertial reference method Short-wavelength irregularities Multi-point chord reference method 5-m wavelength range
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Comparison of Calculation Methods for Potential Reference Crop Evapotranspiration ET_0 in North Xinjiang
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作者 Chunyan YIN Hu LIU +2 位作者 Ruiqiang ZHANG Jian WANG Yongfu WEI 《Agricultural Science & Technology》 CAS 2017年第5期920-923,共4页
Reference crop evapotranspiration (ET_0) is a critical part in water cycle and water balance of ecosystem, which is greatly important to effective utilization of agricultural water resources and for making reasonable ... Reference crop evapotranspiration (ET_0) is a critical part in water cycle and water balance of ecosystem, which is greatly important to effective utilization of agricultural water resources and for making reasonable irrigation system. In order to propose a suitable method for computing ET_0 in North Xinjiang, based on daily meteorological data from May 1 to September30, 2010 provided by Weather Station of Fuhai County, we used FAO56 Penman-Monteith as the standard formula to compute ET_0, compared the differences and relations between such the method and other 4 calculation formulas, and analyzed the cause of the deviation, finally evaluated the applicability of computational method in North Xinjiang. The results showed that the calculation results by FA056 PM Method was approximate to that by FAO Penman method and IA method, of which the relative error was 9.26% and 13.51% respectively, the ET_0 results calculated by PT method and HS method were generally greater than the results by FAO56 PM, and their deviation was very obvious. 展开更多
关键词 North Xinjiang reference crop evapotranspiration Calculation method FAO56 PM
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Development of A Reference Dose for BDE-47,99,and 209 Using Benchmark Dose Methods
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作者 LI Lu Xi CHEN Li +5 位作者 CAO Dan CHEN Bing Heng ZHAO Yan MENG Xiang Zhou XIE Chang Ming ZHANG Yun Hui 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2014年第9期733-739,共7页
Eleven recently completed toxicological studies were critically reviewed to identify toxicologically significant endpoints and dose-response information. Dose-response data were compiled and entered into the USEPA's ... Eleven recently completed toxicological studies were critically reviewed to identify toxicologically significant endpoints and dose-response information. Dose-response data were compiled and entered into the USEPA's benchmark dose software (BMDS) for calculation of a benchmark dose (BMD) and a benchmark dose low (BMDL). After assessing 91 endpoints across the nine studies, a total of 23 of these endpoints were identified for BMD modeling, and BMDL estimates corresponding to various dose-response models were compiled for these separate endpoints. Thyroid, neurobehavior and reproductive endpoints for BDE-47, -99, -209 were quantitatively evaluated. According to methods and feature of each study, different uncertainty factor (UF) value was decided and subsequently reference doses (RfDs) were proposed. Consistent with USEPA, the lowest BMDLs of 2.10, 81.77, and 1698 I^g/kg were used to develop RfDs for BDE-47, -99, and -209, respectively. RfDs for BDE-99 and BDE-209 were comparable to EPA results, and however, RfD of BDE-47 was much lower than that of EPA, which may result from that reproductive/developmental proves to be more sensitive than neurobehavior for BDE-47 and the principal study uses very-low-dose exposure. 展开更多
关键词 BDE Development of A reference Dose for BDE-47 99 and 209 Using Benchmark Dose methods
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Quantum-Mechanical Information Content of Multiples Hartree-Fock Solutions. The Multi-Reference Hartree-Fock Configuration Interaction Method
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作者 Luiz Augusto Carvalho Malbouisson Antonio Moreira de Cerqueira Sobrinho Micael Dias de Andrade 《Journal of Modern Physics》 2014年第7期543-548,共6页
The Hartree-Fock equation is non-linear and has, in principle, multiple solutions. The ωth HF extreme and its associated virtual spin-orbitals furnish an orthogonal base Bω of the full configuration interaction spac... The Hartree-Fock equation is non-linear and has, in principle, multiple solutions. The ωth HF extreme and its associated virtual spin-orbitals furnish an orthogonal base Bω of the full configuration interaction space. Although all Bω bases generate the same CI space, the corresponding configurations of each Bω base have distinct quantum-mechanical information contents. In previous works, we have introduced a multi-reference configuration interaction method, based on the multiple extremes of the Hartree-Fock problem. This method was applied to calculate the permanent electrical dipole and quadrupole moments of some small molecules using minimal and double, triple and polarized double-zeta bases. In all cases were possible, using a reduced number of configurations, to obtain dipole and quadrupole moments in close agreement with the experimental values and energies without compromising the energy of the state function. These results show the positive effect of the use of the multi-reference Hartree-Fock bases that allowed a better extraction of quantum mechanical information from the several Bω bases. But to extend these ideas for larger systems and atomic bases, it is necessary to develop criteria to build the multireference Hartree-Fock bases. In this project, we are beginning a study of the non-uniform distribution of quantum-mechanical information content of the Bω bases, searching identify the factors that allowed obtain the good results cited 展开更多
关键词 Multiple HARTREE-FOCK SOLUTIONS QUANTUM MECHANICAL INFORMATION Content MULTI-referENCE Hartre-Fock Configuration Interaction method
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采用间接法建立苏州地区表观健康成人血清高尔基体蛋白73水平参考区间及验证
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作者 李淑湘 郑维玲 +1 位作者 石燕 魏衍财 《现代检验医学杂志》 2026年第1期161-164,共4页
目的采用间接法建立并验证苏州地区表观健康成人血清中高尔基体蛋白73(GP73)的参考区间。方法回顾性分析2020年5月~2024年4月在南京医科大学附属苏州医院健康体检的1959例受试者,采用酶联免疫吸附试验(ELISA)检测血清中GP73水平。按照... 目的采用间接法建立并验证苏州地区表观健康成人血清中高尔基体蛋白73(GP73)的参考区间。方法回顾性分析2020年5月~2024年4月在南京医科大学附属苏州医院健康体检的1959例受试者,采用酶联免疫吸附试验(ELISA)检测血清中GP73水平。按照性别和年龄分组,参照WS/T 402-2024《临床实验室定量检验项目参考区间的制定》文件要求建立各组参考区间。选取2024年5月~6月该院20例表观健康成人,进行GP73自建参考区间的验证。结果表观健康人GP73水平呈偏态分布,采用百分位数法建立参考区间。线性回归分析发现,男性和女性GP73水平与年龄均呈正相关(r=0.197、0.247,均P<0.01)。男性组GP73水平低于女性组,差异具有统计学意义(Z=-2.145,P=0.032)。按年龄分组,≥60岁组与18~44岁组、45~59岁组GP73水平比较,差异均有统计学意义(Z=-6.623、-6.625,均P<0.05),18~44岁组与45~59岁组GP73水平比较,差异无统计学意义(Z=-0.232,P=0.817)。女性不同年龄分组两两比较,GP73水平差异均有统计学意义(Z=-2.371、-7.571、-4.907,均P<0.05)。经过标准正态离差检验分析不同性别和各年龄段GP73水平差异无实际临床意义(Z<Z*),建立统一的GP73参考区间为≤76.96ng/ml,并进行验证符合标准。结论初步建立适合苏州地区表观健康成人血清GP73参考区间,为临床相关疾病的预防、诊治提供参考。 展开更多
关键词 间接法 高尔基体蛋白73 成人 参考区间 苏州地区
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双标多测法同时测定茯苓中13种三萜类成分的含量
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作者 丁婵 熊文惠 +5 位作者 厉晓 彭思源 龚婕 浦子牛 肖作为 崔培梧 《中成药》 北大核心 2026年第1期129-135,共7页
目的建立双标多测法同时测定茯苓中6α-羟基猪苓酸C、茯苓新酸B、去氢土莫酸、土莫酸、茯苓新酸A、3-表去氢茯苓酸、猪苓酸C、3-表去氢土莫酸、去氢茯苓酸、茯苓酸、松苓新酸、去氢齿孔酸、齿孔酸的含量。方法分析采用Agilent XDB-C_(18... 目的建立双标多测法同时测定茯苓中6α-羟基猪苓酸C、茯苓新酸B、去氢土莫酸、土莫酸、茯苓新酸A、3-表去氢茯苓酸、猪苓酸C、3-表去氢土莫酸、去氢茯苓酸、茯苓酸、松苓新酸、去氢齿孔酸、齿孔酸的含量。方法分析采用Agilent XDB-C_(18)(250 mm×4.6 mm,5μm)色谱柱;流动相水(含0.3%磷酸)-乙腈,梯度洗脱;体积流量1.0 mL/min;柱温25℃;检测波长242、203 nm。以6α-羟基猪苓酸C和茯苓酸为双标,双标线性校正法预测其他成分保留时间;以茯苓酸为内标,计算其他成分相对校正因子,计算其含量。结果13种成分在各自范围内线性关系良好(R^(2)≥0.9993),平均加样回收率99.77%~104.60%,RSD 0.16%~2.88%。双标线性校正法更准确,偏差更小。双标多测法与常规外标法所得结果无显著差异。结论该方法可实现茯苓中主要三萜类成分的快速分析,是该药材切实可行的整体质量评价方法。 展开更多
关键词 茯苓 三萜 含量测定 双标多测法 双标线性校正法
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基于光学方法的黑碳气溶胶计量研究进展
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作者 刘悦 肖骥 +1 位作者 叶婧 刘俊杰 《大气与环境光学学报》 2026年第1期40-56,共17页
黑碳气溶胶作为具有强吸光性的短寿命大气污染物,对全球气候效应具有重要影响,对该污染物的准确监测问题受到国内外广泛关注。目前基于光学法对黑碳气溶胶的测量存在不同原理仪器的结果差异大、测量结果影响因素多、缺乏计量技术标准等... 黑碳气溶胶作为具有强吸光性的短寿命大气污染物,对全球气候效应具有重要影响,对该污染物的准确监测问题受到国内外广泛关注。目前基于光学法对黑碳气溶胶的测量存在不同原理仪器的结果差异大、测量结果影响因素多、缺乏计量技术标准等技术问题。在此背景下,研究并形成统一的黑碳计量及标准化系统有助于减小黑碳测量的不确定度,降低其辐射强迫评估误差。为促进我国黑碳计量的相关研究,本文综述了国际上黑碳气溶胶计量的标准物质及其发生与老化装置以及可溯源的基准方法,并对我国黑碳计量研究未来发展方向进行了展望。 展开更多
关键词 黑碳气溶胶 光学法 标准物质 老化装置 基准方法
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基于惯性基准法的嵌入式地铁轨道动态检测与验证研究
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作者 欧曙光 程中国 +2 位作者 柏成林 刘树松 曹立科 《现代城市轨道交通》 2026年第2期37-44,共8页
轨道作为地铁的重要组成部分,其检测技术水平是保障地铁长期安全运行的关键要素。文章提出一种基于惯性基准法的轨道不平顺计算方法,并结合硬件设备和嵌入式平台,对轨道动态检测系统进行综合设计,从而实现对轨道不平顺的高精度检测。通... 轨道作为地铁的重要组成部分,其检测技术水平是保障地铁长期安全运行的关键要素。文章提出一种基于惯性基准法的轨道不平顺计算方法,并结合硬件设备和嵌入式平台,对轨道动态检测系统进行综合设计,从而实现对轨道不平顺的高精度检测。通过系统测试分析表明,滤波器补偿可有效降低频率幅值,提高检测精度;通过相位调整,可使角速度测量的相对误差降低约80%。根据不同切片数下的钢轨轮廓相似度计算结果,连接件的最佳相似度达86.52%,进而验证轮廓检测结果的准确性。研究提出的轨道检测系统可解决当前检测设备成本偏高、效率不足问题,同时为非接触式的检测方案提供技术参考。 展开更多
关键词 地铁 惯性基准法 惯性测量单元 轨道不平顺 轨道检测 嵌入式设计
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L-苯丙氨酸溶液标准物质研制
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作者 李艾橘 吴颖怡 王磊 《计量与测试技术》 2026年第1期166-171,共6页
按照国家一级标准物质技术规范,以L-苯丙氨酸纯度标准物质为原料,采用重量-容量法,制备浓度为135.2μmol/L、600.0μmol/L、999.9μmol/L的标准物质。经过8个月的稳定性考察,证明其在-80℃储存条件下是稳定的。对均匀性、测量分散性及... 按照国家一级标准物质技术规范,以L-苯丙氨酸纯度标准物质为原料,采用重量-容量法,制备浓度为135.2μmol/L、600.0μmol/L、999.9μmol/L的标准物质。经过8个月的稳定性考察,证明其在-80℃储存条件下是稳定的。对均匀性、测量分散性及其他因素引入的不确定度分量进行分析,相对扩展不确定度分别为1.9%、1.7%、2.0%。该标准物质可满足日常研究和检测需要,用于分析方法评价及L-苯丙氨酸含量检测和检测方法确证,在统一相关量值上发挥作用。 展开更多
关键词 L-苯丙氨酸 标准物质 方法正确性验证
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持久性污染物多氯联苯分析用标准溶液研究
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作者 王立 万康妮 +3 位作者 陈雄飞 高扬 刘美 李甜 《山东化工》 2026年第1期139-147,共9页
本文建立了一种持久性污染物多氯联苯类(PCBs)混合标准溶液的制备方法,并对标准溶液量值进行准确定性定量分析。基于定量核磁共振法(qNMR),以氘代二氯甲烷为溶剂,3,5-二硝基苯甲酸甲酯为核磁内标物,对18种多氯联苯原料的纯度进行了定性... 本文建立了一种持久性污染物多氯联苯类(PCBs)混合标准溶液的制备方法,并对标准溶液量值进行准确定性定量分析。基于定量核磁共振法(qNMR),以氘代二氯甲烷为溶剂,3,5-二硝基苯甲酸甲酯为核磁内标物,对18种多氯联苯原料的纯度进行了定性和定量分析,采用重量-容量法进行溶液配制,以正己烷为介质,制备了18种多氯联苯混合标准溶液。以配制值作为标准溶液的特性量值,采用优化后的气相色谱法考察了不同多氯联苯之间互为杂质情况,并通过F检验验证标准溶液均匀性,t检验验证标准溶液稳定性,结果表明该溶液具备良好的均匀性和稳定性,并对溶液的不确定度进行评定,结果表明研制的正己烷中18种多氯联苯混合标准溶液质量浓度均为100 mg/L,相对扩展不确定度为2%~4%(k=2)。所研制的混合溶液标准物质适用于国家标准GB 5009.190—2014《食品安全国家标准食品中指示性多氯联苯含量的测定》及环境标准HJ 715—2014《水质多氯联苯的测定气相色谱法》,可为环境监测与食品检测中多氯联苯类有害物质残留测定提供溯源保障。 展开更多
关键词 多氯联苯 混合溶液标准物质 定量核磁法 气相色谱法 不确定度
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扩散池法考察不同生产厂家糠酸莫米松乳膏的体外释放度
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作者 王经纬 鲍实 +3 位作者 陈晓颙 尚悦 刘晨曦 胡敏 《医药导报》 北大核心 2026年第1期109-115,共7页
目的建立测定糠酸莫米松乳膏体外释放度的实验方法,对参比制剂和国内8种糠酸莫米松乳膏仿制药的体外释放一致性进行评价。方法采用立式扩散池法测定糠酸莫米松乳膏的释放度,考察释放接收介质、滤膜、搅拌速率、温度等因素对糠酸莫米松... 目的建立测定糠酸莫米松乳膏体外释放度的实验方法,对参比制剂和国内8种糠酸莫米松乳膏仿制药的体外释放一致性进行评价。方法采用立式扩散池法测定糠酸莫米松乳膏的释放度,考察释放接收介质、滤膜、搅拌速率、温度等因素对糠酸莫米松乳膏体外释放行为的影响,比较国内8种糠酸莫米松乳膏仿制药与参比制剂体外释放行为之间的差异。采用释放介质为0.9%氯化钠溶液-乙醇(1:1),滤膜为孔径0.45μm的聚醚砜膜(PES膜),分别于1、3、5、7、12、24 h各取样1次,取样体积1 mL。以高效液相色谱法测定糠酸莫米松的浓度,采用C 16色谱柱(250 mm×4.6 mm,5μm),流动相为甲醇-水(70:30),检测波长254 nm,柱温40℃,流速1.0 mL·min^(-1),进样量20μL。结果方法学验证表明,体外释放方法的滤膜惰性、专属性、灵敏度、选择性均符合要求。糠酸莫米松的定量限为0.2μg·mL^(-1),在0.2~20.0μg·mL^(-1)范围内线性良好(r^(2)=0.99999),回收率为97.1%,稳定性和重复性均良好。参比制剂24 h的释放百分比为1.41%,8种仿制药的释放度为1.93%~62.26%。结论建立的体外释放实验方法准确度好、灵敏度高,可为糠酸莫米松乳膏优化处方、生产工艺及一致性评价提供参考。 展开更多
关键词 糠酸莫米松乳膏 立式扩散池法 体外释放 参比制剂 一致性评价
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A method for calculating probability of collision between space objects 被引量:2
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作者 Xiao-Li Xu Yong-Qing Xiong 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2014年第5期601-609,共9页
A method is developed to calculate probability of collision. Based on geometric features of space objects during the encounter, it is reasonable to separate the radial orbital motions from those in the cross section f... A method is developed to calculate probability of collision. Based on geometric features of space objects during the encounter, it is reasonable to separate the radial orbital motions from those in the cross section for most encounter events that occur in a near-circular orbit. Therefore, the probability of collision caused by differences in both altitude of the orbit in the radial direction and the probability of collision caused by differences in arrival time in the cross section are calculated. The net probability of collision is expressed as an explicit expression by multiplying the above two components. Numerical cases are applied to test this method by comparing the results with the general method. The results indicate that this method is valid for most encounter events that occur in near-circular orbits. 展开更多
关键词 methods: analytical -- reference systems -- catalogs -- space vehicles-- celestial mechanics
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Decreasing Reference Evapotranspiration in a Warming Climate-A Case of Changjiang (Yangtze) River Catchment During 1970-2000 被引量:13
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作者 许崇育 龚乐冰 +1 位作者 姜彤 陈德亮 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2006年第4期513-520,共8页
This study deals with temporal trends in the Penman-Monteith reference evapotranspiration estimated from standard meteorological observations, observed pan evaporation, and four related meteorological variables during... This study deals with temporal trends in the Penman-Monteith reference evapotranspiration estimated from standard meteorological observations, observed pan evaporation, and four related meteorological variables during 1970-2000 in the Yangtze River catchment. Relative contributions of the four meteorological variables to changes in the reference evapotranspiration are quantified. The results show that both the reference evapotranspiration and the pan evaporation have significant decreasing trends in the upper, the middle as well as in the whole Changjiang (Yangtze) River catchment at the 5% significance level, while the air temperature shows a significant increasing trend. The decreasing trend detected in the reference evapotranspiration can be attributed to the significant decreasing trends in the net radiation and the wind speed. 展开更多
关键词 reference evapotranspiration Penman-Monteith method temporal trend Changjiang(Yangtze) River catchment China
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Analogue correction method of errors and its application to numerical weather prediction 被引量:10
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作者 高丽 任宏利 +1 位作者 李建平 丑纪范 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第4期882-889,共8页
In this paper, an analogue correction method of errors (ACE) based on a complicated atmospheric model is further developed and applied to numerical weather prediction (NWP). The analysis shows that the ACE can eff... In this paper, an analogue correction method of errors (ACE) based on a complicated atmospheric model is further developed and applied to numerical weather prediction (NWP). The analysis shows that the ACE can effectively reduce model errors by combining the statistical analogue method with the dynamical model together in order that the information of plenty of historical data is utilized in the current complicated NWP model, Furthermore, in the ACE, the differences of the similarities between different historical analogues and the current initial state are considered as the weights for estimating model errors. The results of daily, decad and monthly prediction experiments on a complicated T63 atmospheric model show that the performance of the ACE by correcting model errors based on the estimation of the errors of 4 historical analogue predictions is not only better than that of the scheme of only introducing the correction of the errors of every single analogue prediction, but is also better than that of the T63 model. 展开更多
关键词 numerical weather prediction analogue correction method of errors reference state analogue-dynamical model
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Standardization in laboratory medicine: Adoption of common reference intervals to the Croatian population
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作者 Zlata Flegar-Me?tri? Sonja Perkov Andrea Radeljak 《World Journal of Methodology》 2016年第1期93-100,共8页
Considering the fact that the results of laboratory tests provide useful information about the state of health of patients, determination of reference value is considered an intrinsic part in the development of labora... Considering the fact that the results of laboratory tests provide useful information about the state of health of patients, determination of reference value is considered an intrinsic part in the development of laboratory medi-cine. There are still huge differences in the analytical methods used as well as in the associated reference intervals which could consequently significantly affect the proper assessment of patient health. In a constant effort to increase the quality of patients' care, there are numerous international initiatives for standardiza-tion and/or harmonization of laboratory diagnostics in order to achieve maximum comparability of laboratory test results and improve patient safety. Through the standardization and harmonization processes of analytical methods the ability to create unique reference intervals is achieved. Such reference intervals could be applied globally in all laboratories using methods traceable to the same reference measuring system and analysing the biological samples from the populations with similar socio-demographic and ethnic characteristics. In this review we outlined the results of the harmonization processes in Croatia in the field of population based reference intervals for clinically relevant blood and serum constituents which are in accordance with ongoing activity for worldwide standardization and harmonization based on traceability in laboratory medicine. 展开更多
关键词 Calibration traceability Applicability of referENCE INTERVALS Harmonization and standardisation External quality assessment International Federation of Clinical Chemistry enzyme referENCE methods Amino- TRANSFERASE "common" referENCE INTERVALS CREATININE enzymatic method
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Determining reference conditions for TN,TP,SD and Chl-a in eastern plain ecoregion lakes,China 被引量:9
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作者 Shouliang Huo Beidou Xi +4 位作者 Jing Su Fengyu Zan Qi Chen Danfeng Ji Chunzi Ma 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2013年第5期1001-1006,共6页
Establishing the nutrient reference condition(baseline environmental condition) of lakes in an ecoregion is a critical consideration in the development of scientifically defensible aquatic nutrient criteria.Three me... Establishing the nutrient reference condition(baseline environmental condition) of lakes in an ecoregion is a critical consideration in the development of scientifically defensible aquatic nutrient criteria.Three methods were applied to determine reference conditions in the Eastern plain ecoregion lakes with respect to total phosphorus(TP),total nitrogen(TN),planktonic chlorophyll a(Chl-a) and Secchi depth(SD).The reference condition value for the lakes in the Eastern plain ecoregion by the trisection method is TP of 0.029 mg/L,TN of 0.67 mg/L,Chl-a of 3.92 mg/m 3,SD of 0.85 m,and the reference condition range by the lake population distribution approach is TP of 0.014-0.043 mg/L,TN of 0.360-0.785 mg/L,Chl-a of 1.78-4.73 mg/m 3,SD of 0.68-1.21 m.Additionally,empirical models were developed for estimating the reference Chl-a concentration and SD successfully for lakes in the Eastern plain ecoregion.Overall,the data suggest that multiple methods can be used to determine reference conditions and that in Eastern plain ecoregion lakes the reference condition corresponds to a mesotrophic status. 展开更多
关键词 lake reference condition lake population distribution approach trisection method model prediction
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Assessing Climate Change Impact on Future Reference Evapotranspiration Pattern of West Bengal, India 被引量:1
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作者 Saon Banerjee Benukar Biswas 《Agricultural Sciences》 2020年第9期793-802,共10页
Considering the importance of reference evapotranspiration (RET) in agriculture, hydrology and meteorology, the research problem was taken to assess the RET during winter season under projected climatic situation of W... Considering the importance of reference evapotranspiration (RET) in agriculture, hydrology and meteorology, the research problem was taken to assess the RET during winter season under projected climatic situation of West Bengal, India. The Penman-Monteith method was used in the study as it is the most accurate method of estimating RET. However, validation of the output of the equation was done with the help of observed data set. The data analysis was carried out using NCAR Command Language (NCL). The result clearly shows that the reference ET of the study area will be increased in the tune of 13% to 32% in the year 2050 compared to present RET level. Analysis of actual rainfall data shows a decreasing trend of winter rainfall in the study region. The projected rainfall data also follows the same pattern. Thus, the combination of low rainfall and higher ET value will demand more irrigation requirement for winter crops in West Bengal. The temporal changes of RET on decadal basis and spatial variation of RET for each decade have been observed and discussed in the paper. 展开更多
关键词 Climate Change reference Evapotranspiration Penman-Monteith method NCAR Command Languages West Bengal
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