关于Bernstein-Bezier 算子对一类绝对连续函数的逼近

Bernstein-Bezier 算子是一种重要的逼近算子, 在计算机辅助几何设计中也扮演了重要角色. 为了进一步了解它的理论及其逼近性质, 研究了它对一类绝对连续函数的逼近. 本文主要利用经典的Bojanic-Cheng 分解方法, 结合分析技术, 分别讨论了Bernstein-Bezier 算子在0=1 时, 对这类绝对连续函数的逼近. 首先扩展了文献Liu 的结果, 得到了 Bernstein-Bezier 算子的一阶中心绝对矩B?; 接着估计了另外一项B?, 最后得到了比较精确 的收敛价.国家自然科学基金( 10571145

Catmull-Clark 曲面控制网格的收敛性质

文献[ 4] 给出Catmull-Clar k 细分曲面控制网格的收敛速率和一个误差计算公式. 本 文在这基础上提出一个新的算法, 并借助此新算法得到关于Catmull-Clar k 细分曲面控制网络的收 敛速率的更精确的估计和给出更好的误差计算公式国家自然科学基金计划( 10571145) 资

Developing On-site,Quick Screening Platform for Artificial Pigments in Food Using Surface-enhanced Raman Spectroscopy

已有研究表明食品加工过程中添加的人工合成色素不仅不能提供营养物质,而且可能是导致小儿多动症的来源之一,影响儿童智力发育.基于表面增强拉曼光谱(SERS)原理和便携式拉曼光谱仪,提出了一种非定向的现场快速筛查方法.该方法只需对疑似含有人工合成色素的固体或液体状食品样品进行简单前处理,即可进行SERS检测.样品前处理和检测的总时长不超过15 min,检出质量浓度在1 mg/L水平,可有效满足政府职能部门的现场执法需求.除具有快速、方便、灵敏度高等特点之外,该检测方法的最大优势在于实现了未知样品的现场非定向测试:在同一种前处理过程和检测方法下,可对食品中常添加的亮蓝、胭脂红、日落黄、柠檬黄、苋菜红和诱惑红6种人工合成色素进行快速鉴定和半定量分析.As widely used additives in food processing,artificial pigments have no any nutrition but are potential sources of hyper-activity and affect the intellectual development of children.On the basis of surface-enhanced Raman spectroscopy( SERS) and portable Raman instrument,we developed a non-targeting,on-site and quick screening platform for artificial pigments in food matrix. SERS measurement could be carried out after the food matrix( either in solid or liquid states) being simply pretreated for 15 min.The detectable concentration is as low as 1 mg / L,a level meeting the demand of the on-site enforcement by the government.Besides the advantages of quick,easy-on-going,and high sensitivity,the most distinguished point of SERS is the non-targeting qualitative on-site detection for the typical pigment additives,including brilliant blue,carmine,sunset yellow,lemon yellow,amaranth and allura red,et al.,while both the pretreatment procedure and the SERS detection remain the same.国家自然科学基金(21473140);; 福建省高校产学合作项目(2016Y4012);; 中央高校基本科研业务费专项(2072016011

表面增强拉曼光谱法在食品中亚硝酸盐的快速筛查研究

建立了采用表面增强拉曼光谱对香肠等食品中亚硝酸盐的快速筛查方法。检测样品经简单提取、衍生后直接进行拉曼光谱检测,整个前处理时间不超过15分钟。通过亚硝酸盐衍生物的指纹图谱定性,本方法能够对各种食品中的亚硝酸盐含量准确筛查,检出限为30 mg/kg,能够满足国家卫生标准的限量要求。该方法前处理简便快速,结果准确,可以作为一种高灵敏、无假阳性的非定向快速筛查手段。该方法可用于检测食品中亚硝酸盐的滥用添加,满足职能部门的现场执法和实验室预检需求。国家自然科学基金（21703187）厦门大学校长基金（20720170102）江苏省产学研前瞻项目（BY2018200

Developing fast laboratory screening platform for sulfate dioxide in food by surface-enhanced Raman spectroscopy

基于表面增强拉曼光谱(SERS)的指纹图谱的高能量分辨率,以位于~630; cm~(-1)亚硫酸根的特征峰为定性和定量依据,本文开展了食品中滥用和非法添加二氧化硫的直接检测研究:一种检测流程实现了不同食品基质中二氧化硫的; 高灵敏检测,最低检出浓度达1 mg; kg~(-1)的水平.针对实际样本的传统蒸馏法前处理流程的一些不足以及SERS检测的指纹图谱优势,本文进行了三方面显著改进:; (1)碳酸钙和沸石取代氮气以提高二氧化硫的挥发提取效率; (2)草酸取代盐酸酸化蒸馏溶液,以有效避免挥发性强酸对操作环境的危害;; (3)氢氧化钠溶液代替乙酸铅溶液作为吸收液,以防止二次污染.环境友好、灵敏度高和不受基质干扰等特点使得本方法有望取代经典蒸馏法和比色法,用于食品; 中非法添加二氧化硫类添加剂的快速高效筛查.The direct detection of sulphur dioxide has been realized in various; food matrixes with high sensitivity and high selectivity, on the basis; of the integration of the high energy resolution of the finger-print; spectrum of surface-enhanced Raman spectroscopy and the universal but; easy-on-going pretreatment procedure. The characteristic peak of sulphur; dioxide at ~630 cm~(-1) was applied as the qualitative and quantitative; standard, which displayed a lowest detectable concentration at the 1 mg; kg~(-1) level for the spiked food samples. The key point of the high; sensitivity and selectivity is the effective pretreatment born out of; the standard distillation one, which has been improved in the three; parts. (1) Using CaCO_3 and Zeolite instead of N_2 gas as the bubbling; reagent. (2) Using oxalic acid as the acidic distillation solution to; eliminate the hazards from acid volatilization, such as hydrochloric; acid. (3) Using diluted sodium hydroxide solution as the absorption; reagent instead of lead acetate solution to avoid the secondary; pollution. With the three distinguished advantages of environment; friendly, high sensitivity and free of matrix interference, the proposed; method has great potential to replace the traditional ones for the fast; screening of the illegal or abused sulphur dioxide in food.国家自然科学基金; 福建省高校产学合作项目; 中央高校基本科研业务费专项资

基于表面增强拉曼光谱的合成色素专利蓝V的快速检测

食品安全问题一直是社会和广大群众关注的焦点问题,食品安全现状较为严峻,因此实现食品中有害物质的快速检测具有重要的实际意义。合成色素是一种常见的食品添加剂,然而合成色素的超标添加和非法添加依旧是食品安全中的重要问题之一,极大地危害人民群众的身体健康和食品工业的健康发展。常见的合成色素检测方法,均存在耗时长、费用高等缺点,不适应于合成色素的实时监测和快速筛查。为克服传统方法的缺点,提出利用表面增强拉曼光谱检测技术对合成色素进行检测,该方法具有检测速度快、检测灵敏度高等优点,能够达到现场实时检测的目的。此外,由于拉曼检测方法往往依赖于复杂的样品前处理操作,而常见的固相萃取技术一般依赖于人工操作,过程复杂且耗时较长,严重影响食品快速检测效率。因此,开发了一种全自动固相萃取装置,通过设计嵌入式硬件电路系统及其软件,精确控制蠕动泵流速和多路阀门开关实现了活化、上样、淋洗、洗脱四个步骤的全自动操作和参数控制,从而达到食品样品的全自动快速固相萃取。在实验部分,配制不同专利蓝V浓度的果汁饮料,然后利用该装置对果汁中的专利蓝V进行前处理,对萃取柱填料和萃取中各个步骤的时间和试剂进行了合理的选择,利用表面增强拉曼光谱检测技术成功地检测了合成色素中的专利蓝V。实验结果表明,所研制的自动固相萃取装置对比传统手工萃取,每个样品节省了近一半的萃取时间（10 min降为5 min）且能够同时处理5个样品,萃取时间稳定不易受人为因素影响,从而极大地提高了萃取效率和稳定性。此外,通过自动萃取获得的样品,对比手工萃取操作,因其受外界干扰相对较小,能够得到更强的拉曼光谱信号（约增强50%）,获得了满意的萃取效果。对不同浓度的专利蓝V样品的结果显示,该方法能够实现检出质量浓度在0.5 mg·L-1水平,可有效满足现场监测需求。具有快速、方便、灵敏度高等特点。国家自然科学基金项目(21874113)资

On the Rate of Convergence of Bernstein-Bézier Operator for Some Absolutely Continuous Functions

Bernstein-Bézier算子是一种重要的逼近算子,在计算机辅助几何设计中也扮演了重要角色.为了进一步了解它的理论及其逼近性质,研究了它对一类绝对连续函数的逼近.本文主要利用经典的Bojanic-Cheng分解方法,结合分析技术,分别讨论了Bernstein-Bézier算子在0<α≤1及α≥1时,对这类绝对连续函数的逼近.首先扩展了文献Liu的结果,得到了Bernstein-Bézier算子的一阶中心绝对矩B(nα)(t-x,x);接着估计了另外一项B(nα)(t∫xφx(u)du,x),最后得到了比较精确的收敛价.The purpose of this paper is to investigate the rate of convergence of Bernstein-Bézier Operator for some absolutely continuous functions.The approximation properties were studied in the case of 0<α≤1 and α≥1 respectively.By using Bojanic-Cheng's method and analysis techniques,the rate of convergence of Bernstein-Bézier Operator was derived.In the first,the authors extended the result of Liu Z X and got the first central absolute moment B~((α))_n(t-x,x).Later,the authors estimated the other part B~((α))_n(∫~t_xφ_x(u)du,x).Lastly,an asymptotically optimal estimate was obtained.The result is helpful to understand the properties of Bézier Operator well,thus further research can be done.国家自然科学基金(10571145)资

Rapid detection of Rhodamine B in raw paprika and other food based on SERS technique

目的:罗丹明B(Rhodamine; B,RB)是一种人工合成的三苯甲烷类碱性染料,因其具有潜在的毒性、致癌性被禁止在食品中添加。目前,在中国还没有关于罗丹明B检测的国家标准,也没有; 快速检测标准,建立合适的现场快速检测方法迫在眉睫。方法:借助表面增强拉曼光谱(SERS)技术,以金纳米溶胶为拉曼信号增强模块,利用自制样品前处理; 仪与便携式拉曼光谱检测仪,实现对辣椒制品、腊肉、果汁、葡萄酒等食品中RB的快速检测。结果:快速前处理技术与常规方法相比,SERS谱图结果差异不明; 显,且不受样品其他成分干扰,但分析时间由常规的40~50 min缩短到约10; min,大大提高了检测效率;同时,以样品提取液为基质的RB溶液最低检测浓度可以达到0.5 mg /kg;以RB在1355; cm~(-1)处的特征峰为内标信号进行归一化计算,在100、200、300 mug; /L三个添加水平下,得到其平均回收率在81.1%~87.0%之间,相对标准偏差RSD在2.1%~3.0%内。结论:通过对多种实际样品检测并将结果; 与成熟的实验室液相色谱法相比较,发现本检测方法样品前处理简单,耗时少,检测结果准确可靠,且仪器设备便携、易操作,可用于食品中RB的现场快速筛查或; 实验室预检。Objective: Rhodamine B is one kind of synthetic alkaline; triphenylmethane dye,which have been used as a food additive.But now it; is proved to be a toxic and cancer-causing substance,and is forbidden to; artificially add into food in China and EU. At present,the government; has not enacted relevant testing standards,and no on-site test methods; was put forward. Therefore it is imminent to establish an on-site rapid; detection method.Method: Based on surface enhanced Raman spectroscopy; (SERS)technique,this experiment achieved the rapid detection of; rhodamine B in chilli products,such as bacon,fruit juice, wine and other; foods,used gold nanoparticle sol as Raman signal enhancement module,a; home-made laser Raman spectra pretreatment apparatus and a portable; Raman spectrum detector.Result: Compared with the conventional; methods,the difference of SERS spectra was not obvious,and the results; also were not affected by the sample composition,though the experimental; time was shorten from 40~50 min to about 10 min,and the minimum; detection concentration for RB was 0.5 mg /kg.By using the intensity of; 1355cm~(-1) peak as a normalization standard,the recoveries for chili; spikes(100,200,300 mug /L)in chilli powder ranged from 81.1% ~87.0% and; the relative standard deviations(RSD)from 2.1% to 3.0%.Conclusion: The; actual samples purchased from the supermarket were tested by the quick; method mentioned in this study.The results told us that this method was; reliable compared with proven technique of LC,and the device used in; this experiment is portable and easy to be operated, and the results; also showed us that this method can be applied for site inspection and; preliminary inspection in laboratory.国家重大科学仪器设备开发专项项目; 福建省科技计划项目; 福建省教育厅中青年项

Convergence Property of Control Meshes of Catmull-Clark Surfaces

文献[4]给出Catmull-Clark细分曲面控制网格的收敛速率和一个误差计算公式.本文在这基础上提出一个新的算法,并借助此新算法得到关于Catmull-Clark细分曲面控制网络的收敛速率的更精确的估计和给出更好的误差计算公式.Article [4] gave the convergence rate of control meshes of Catmull-Clark subdivision surfaces and a computational formula for error estimate.In this paper,we present a new algorithm.By means of this new algorithm we obtain a more precise estimate of convergence rate of control meshes of Catmull-Clark subdivision surfaces and a better computational formula for error estimate.国家自然科学基金计划(10571145)资

Raman Spectroscopy Measurement System of Dual Wavelength Laser Module

荧光干扰是拉曼光谱检测过程中常见的干扰因素之一,而移频激发法是一种有效的克服荧光干扰的检测手段。移频激发法利用两个波长相近的激光分别激发被测物质,并将获得的拉曼光谱进行差谱。由于两次激发的荧光背景相同,而拉曼特征峰会产生平移,因此可有效地消除荧光背景的干扰,进而利用一定的算法还原拉曼特征峰。移频激发法的关键在于两个激发光波长的稳定性,不稳定的波长差将严重影响对拉曼特征峰的还原效果。本文研制了一种拉曼光谱测试系统,该系统的双波长ld模块能够产生两个波长稳定的激发光(分别为784.7和785.8 nM),满足移频激发法的测试要求。影响激发光波长稳定性的因素主要是光功率和温度,本系统中对这两个因素均进行了实时的监控,以保证激发光波长的稳定。系统的硬件部分主要包括ArM主控板、双波长ld模块及其驱动电路、温度控制板、数字光开关、光谱检测光路和光纤探头(两个高功率的蝶形封装激光器);软件部分可自动获取被测物质的拉曼光谱图,并对其进行后续的处理。在稳定性测试实验中,对系统驱动电源电流和激光器温度的稳定性均进行了测试。测试结果显示,电流波动范围小于0.01 MA、温度变化范围小于0.004℃,能够有效地保证激发光波长的稳定性。最后,对某品牌花生油进行了拉曼光谱检测,并对检测结果进行了处理,获得了良好的效果。Fluorescence interference is one of common interference factors during detection of Raman spectroscopy,while shiftedexcitation Raman difference spectroscopy(SERDS) is an effective detection means to reject it SERDS excites the test substance by two laser with different wavelengths,then difference the obtained Raman spectroscopies.SERDS can eliminate the fluorescence interference effectively,because the fluorescence backgrounds of the two spectroscopies are the same while the Raman peaks are translated.The key factor of SERDS is the stability of the two excitation light wavelengths,the instability of wavelength difference would seriously affect the characteristics of the Raman peak reproduction.In this paper,the Raman spectroscopy measurement system is presented,where dual wavelength laser module can stably produce two bunch of excitation light(respectively 784.7 and 785.8 nm),which satisfies the requirements of SERDS detection.The major factors influencing wavelength of the laser are laser power and temperature.The system monitors them in real time to guarantee the stability of exciting light's wavelength.The hardware framework of this measurement system is mainly composed of ARM,dual wavelength laser module as well as its driving circuit,temperature control circuit,a digital optical switch,a spectrometer;the software of this system can achieve the Raman spectrogram automatically and then carry on the subsequent processing.The stability tests of this system for drive current and laser temperature are done.The experimental results demonstrate that the range of current proves to be less than 0.01 mA,the range of temperature less than 0.004℃.The system can guarantee the stability of excitation wavelength effectively.Finally,perform the Raman spectroscopy detection to sesame oil of some brand and get good results.国家重大科学仪器设备开发专项项目(2011YQ03012417)资