317 research outputs found

    Euler梁自由振动的Hermite再生核无网格分析

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    基于Hermite再生核无网格近似,建立了Euler梁自由振动分析的伽辽金无网格离散方程.针对常见的几种典型边界条件的Euler梁自由振动问题,详细分析了前两阶频率的误差和收敛性.结果表明,与传统仅采用挠度近似的伽辽金无网格法和Hermite有限元法相比,考虑节点转角对挠度近似影响的Hermite无网格方法具有更高的精度,为Euler梁振动分析提供了一种高精度的数值方法

    海洋有机质的光谱分析方法评述

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    海洋有机质的光谱分析已成为海洋碳循环的研究热点之一。本文从天然有机质吸收光谱和荧光光谱分析的基本原理入手,系统梳理了有机质光谱分析中容易被忽视的基本概念,讨论了过滤与保存方式、p H值、荧光内滤效应等对有机质光谱分析的影响。结合色氨酸、酪氨酸、腐殖酸及大量现场样品的实验结果,对吸收光谱和三维荧光光谱的不同解析方法进行了系统的分析与对比。基于在南海、西菲律宾海获取的现场调查数据,对于文献中常用的荧光指数(FI)、腐殖化指数(HIX)、自生源指数(BIX)等光谱参数的内在含义及其在海洋环境中的适用性进行了评述。此外,还归纳和总结了胶体有机质和颗粒有机质荧光分析的最新进展,并对今后在光谱分析与观测领域有待完善和突破的一些关键领域进行了展望。国家自然科学基金面上项目(41876083;41276064);;“科学”号高端用户项目(KEXUE2017G11;KEXUE2018G03);;厦门市海洋与渔业局项

    平滑运动条件下的图形颜色及形状加工特性的研究

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    本研究对在运动图形识别过程中,有关图形的不同特征(颜色、形状等)的加工特性、方向性效应以及不同空间位置(或时间间隔)对图形识别的影响了探讨。结果发现,视觉系统在运动信息加工时,对目标的不同特征的加工存在不均衡性,加工的难度有差异。颜色的加工难度要比形状的加工难度小。视觉系统对不同运动方向上的图形匹配反应特性也存在差异,图形匹配过程受时间或距离因素的影响,匹配的反应时随着两个比较图形之间的空间距离的增加而减少

    ONE NEW SPECIES AND ONE NEW RECORD SPECIES of EIRENIDAE FROM THE TAIW AN STRAIT,CHINA

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    记述了采自台湾海峡软水母亚纲lEPTOMEduSAE HAECkEl,1866、和平水母科EIrEnIdAE HAECkEl,1879 1新种,无疣杯水母PHIAlOPSIS AVErruCIfOrMIS SP.nOV.和我国海域1新纪录种,母芽侧丝水母HElgICIrrHA MEduSIfErA(bIgElOW,1909),对其形态特征进行描述。模式标本保存于国家海洋局第三海洋研究所。The samples of Eirenidae were collected from the Taiw an Strait,China( 20.85°- 27.06° N,114.92°- 121.24°E) during July 2006 and Jan.2007.One new species of Phialopsis averruciformis sp.nov.and one new record species of Helgicirrha medusifera( Bigelow,1909) are described in the present paper based on the type specimens from the T aiw an Strait,China.The specific diagnosis of the new species is as follows.我国近海海洋综合调查与评价(908专项)(908-ZC-Ⅱ-02;908-01-BC07;908-02-0102;908专项海洋生物样品库); 国家海洋局“全球变化与海气相互作用专项”资助~

    Concentrations and distribution of polycyclic aromatic hydrocarbons and organo chlorides in surface sediment of Xiamen Western Harbour and Minjiang Estuary

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    参考美国EPA标准方法对厦门西港和闽江口的表层沉积物样品中持续性有机污染物PAHs、PCBs、和DDTs的含量及分布进行分析和考察 ,并对若干污染特征及成因进行探讨 .结果表明 ,厦门西港沉积物样品中总PAHs含量 (ng/ g(干重 ) )较闽江口海域为高 ,其中厦门样品测值范围是 42 5 3 - 15 2 2 4,大多高于 10 0 0 ,推断主要来源于石油类污染 ;闽江口为 316 8-12 6 0 7,大多低于 10 0 0 ,化石燃料燃烧可能是其主要来源 .PCBs和DDT的分析结果表明 ,PCBs并非两海域的主要污染物 ,其含量 (ng/ g(干重 ) )测值范围是厦门西港 9 72— 33 72 ,闽江口 8 71— 30 5 5 ;DDT类含量测值 (ng/g(干重 ) )厦门西港高于闽江口 ,范围分别为 8 6 1— 73 70和 6 17— 30 70 (河口高值站位为 6 3 88) ,空间分布呈近岸高于远岸趋势 .同时表明 ,在厦门海域表层沉积物中DDD是主要降解产物 ,而在闽江口DDE为主要降解产物The U.S.EPA analytical methods were employed to examine surface sediment concentrations of polycyclic aromatic hydrocarbons (PAHs) and organo chlorides (PCBs and DDTs) in Xiamen Western Harbour (XM),in June,1999,and Min River Estuary (MJ) in Oct., 1996.The spatial distribution and main possible sources of these pollutants were discussed.The ranges of PAHs concentration (ng/g(DW)) are 425-1520,with most values higher than 1000 in XM samples,and 315-1260,with most values lower than 1000 in MJ samples respectively.The main possible sources of sediment PAHs were identified as petroleum pollutants for Xiamen Western Harbour,and fossil fuel combustion products by river input for Minjiang Estuary,respectively.Sediment PCBs were found not the main pollutants in the study areas,with concentrations(ng/g(DW))ranging from 9.72 to 33.72,and from 8.71 to 30.55,in XM samples and MJ samples,respectively.Concentrations (ng/g(DW)) of sediment DDT and its degraded compounds show the trend of decreasing off the shore,while ranging from 20 to 70,and 6 to 30,in XM samples and MJ samples,respectively.Meaningful information also displays that the main degradation products are DDD in XM samples and DDE in MJ samples.As for the general results,the disadvantage of hydrodynamics,industrial and municipal wastewater discharge,and harbour activities are inferred as the main aspects of the factors affecting pollution in Xiamen Western Harbour,comparing with those in Minjiang Estuary,which is significantly affected by Minjiang River input.Measures for pollution prevention thus should be taken differently in the two areas

    Efficacy of Zaozhu Yinchen Recipe for Treating Non-alcoholic Steatohepatitis and Its Effect on Free Fatty Acid and TNF-α

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    目的观察皂术茵陈方治疗非酒精性脂肪性肝炎(non-alcoholic steatohepatitis,NASH)患者的临床疗效,并探讨其对游离脂肪酸(free fatty acid,FFA)及TNF-α的影响。方法采用随机数字表法将120例NASH患者分为治疗组及对照组,每组60例。治疗组予中药皂术茵陈方,每日1剂;对照组予水飞蓟宾葡甲胺片200 mg口服,每日3次,两组均治疗24周。分别于治疗前后通过检测血清ALT、AST活性及TC、TG水平;行腹部CT计算肝脾CT比值;应用肝组织病理检查评价非酒精性脂肪性肝病活动度积分(NAFLD activity score,NAS)及纤维化程度以评价临床疗效;并检测血清FFA及TNF-α含量。结果与本组治疗前比较,两组治疗后血清ALT、AST、TC、TG、FFA、TNF-α水平、肝组织NAS积分及症状体征积分均明显降低,肝纤维化程度明显改善(P<0.05,P<0.01),且治疗组降低更明显(P<0.05)。治疗24周后,治疗组肝纤维化分期总有效率及临床总有效率分别为80.00%(48/60)、85.00%(51/60),明显高于对照组[60.00%(36/60)、73.33%(44/60)],两组比较,差异有统计学意义(P<0.05,P<0.01)。结论皂术茵陈方可改善NASH患者的临床疗效,其作用可能与抑制血清FFA及TNF-α水平有关。Objective To observe the efficacy of Zaozhu Yinchen Recipe(ZZYCR) on non-alcoholic steatohepatitis(NASH) patients, and to explore its effect on serum free fatty acid(FFA) and tumor necrosis factor α(TNF-α).Methods Totally 120 patients with NASH were randomly assigned to the treatment group(60 cases,treated with ZZYCR, one dose per day) and the control group(60 cases, treated with Silibin Meglumine Tablets, 20 mg each time, thrice per day). The therapeutic course for all was 24 weeks. Serum levels of ALT and AST activities, TC and TG levels were detected before and after treatment. Peritoneal CT was performed in all patients, and CT ratios of liver and spleen calculated. NAFLD activity score(NAS) and degree of hepatic fibrosis were assessed using pathological examinations of liver tissue, and efficacy also evaluated. Serum contents of FFA and TNF-αwere also detected. Results Compared with before treatment in the same group, activities of ALT and AST, serum levels of TC, TG, FFA, and TNF-α, NAS, scores of symptoms and signs all obviously decreased, degree of hepatic fibrosis was obviously improved in the two groups(P < 0. 05, P < 0. 01). These changes were more obviously seen in the treatment group(P < 0. 05). After 24-week treatment, the total effective rate and total clinical efficacy were 80. 00%(48/60 cases) and 85. 00%(51/60 cases) in the treatment group, obviously higher than those in the control group [60. 00%(36/60 cases) and 73. 33%(44/60 cases) respectively], with significant difference(P < 0. 05, P < 0. 01). Conclusion ZZYCR could improve the clinical efficacy of NASH patients, and its mechanism might be associated with inhibiting serum levels of FFA and TNF-α.国家自然科学基金资助项目(No.81503529,81274155);; 福建省自然科学基金面上资助项目(No.2014J01374);; 福建省卫生厅中医药项目(No.wzpw201308);; 厦门市科技计划项目(No.3502Z20134020

    Keyword Search over Relational Databases

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    介绍了基于关系数据库的关键词查询问题的研究背景;阐述了解决该问题的两大类方法,即基于数据图的方法和基于模式图的方法,并详细介绍了各种方法的原理以及各自的优缺点;最后展望了未来的研究方向。First, the research background of keyword search over relational databases is presented and is followed by a detailed description of two solutions to this problem, i.e., data graph based and schema graph based methods, and a discussion of the principles, advantages and disadvantages of these methods is also mentioned. Finally, some future trends in this area are discussed.Supported by the National Natural Science Foundation of China under Grant No.50604012 (国家自然科学基金); the National High-Tech Research and Development Plan of China under Grant No.2009AA01Z150 (国家高技术研究发展计划(863)

    Mechanism of geniposide in improving free fatty acid metabolism in rats with non-alcoholic fatty liver disease

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    观察栀子苷改善非酒精性脂肪性肝病的效果,从游离脂肪酸探讨栀子苷调节非酒精性脂肪性肝病的作用机制。健康雄性Wistar大鼠40只,随机分为4组:正常组、模型组、栀子苷组和血脂康组,每组大鼠10只,正常组大鼠给予正常大鼠饲料喂养,其余3组大鼠均采用高脂饲料喂养以诱导非酒精性脂肪性肝病,造模时间为8周,从第5周起至第8周末,栀子苷组和血脂康组分别灌服相应的药物。记录大鼠体重、肝湿重、脂肪质量;用相应方法检测肝组织TG,FFA,FAS,AMPK,ACCase及Malonyl-Co A含量,血清CHO,LDL-C的含量,血清AST,ALT的活性;观察肝脏组织肉眼及病理变化(HE染色法)。结果显示,与正常组相比,模型组大鼠的体重;肝湿重;脂肪重;血清CHO,LDL-C,ALT,AST;肝组织TG,FFA,FAS,ACCase及Malonyl-Co A含量皆显著升高(P<0.01);肝组织AMPK活性显著降低(P<0.01),肝组织肉眼外观及病理切片脂肪变性明显,并出现炎症损伤;与模型组相比,栀子苷组大鼠体重、脂肪质量、肝组织FFA含量、血清ALT,AST活性均显著降低(P<0.01),肝湿重,肝组织TG,FAS,ACCase及Malonyl-Co A含量明显降低(P<0.05),肝组织AMPK活性明显增多(P<0.05),肝脏肉眼外观及病理学表现均有所改善;与模型组相比,血脂康组大鼠的肝湿重、脂肪质量、肝组织TG,FFA和血清LDL-C水平明显降低(P<0.05);与血脂康组相比,栀子苷组大鼠的体重、脂肪质量、肝组织FFA含量均显著降低(P<0.01),其他方面无明显差异。结果表明,栀子苷具有显著的改善高脂饮食诱导的大鼠非酒精性脂肪性肝病的药理效应;其改善大鼠非酒精性脂肪性肝病的游离脂肪酸代谢是通过调节"AMPK-ACCase-Malonyl-Co A-FFA"轴来实现的。To observe the effect of geniposide on non-alcoholic fatty liver disease( NAFLD),and discuss the mechanism of geniposide for NAFLD from the aspect of free fatty acid,forty healthy Wistar male rats were randomly divided into normal group,model group,geniposide and Xuezhikang group. The rats in normal group were fed with normal diets,and the rats in other 3 groups were given with high-fat diet for 8 weeks to induce the NAFLD models. From the week 5 to end of week 8,the rats in geniposide and Xuezhikang group were intervened with corresponding medicines. The body weight,liver wet weight,and fat weight of the rats were recorded.Visual and pathological changes in hepatic tissues were observed with HE staining. The contents of TG,FFA,FAS,AMPK,ACCase and Malonyl-Co A in hepatic tissue,contents of CHO and LDL-C in serum and activities of AST and ALT in serum were detected by using corresponding methods. The results showed that the body weight,liver wet weight,and fat weight of the rats,CHO,LDL-C,ALT and AST levels in serum,TG,FFA,FAS,ACCase and Malonyl-Co A levels in hepatic tissues of the rats in model group were significantly higher than those in normal group( P < 0. 01),while AMPK activity was significantly lower than that of the normal group( P < 0. 01),with obvious visual and pathological steatosis in hepatic tissues,and inflammatory injury occurred in model group. Compared with the model group,body weight of the rat,fat weight,levels of FFA in hepatic tissues,ALT and AST activities in serum,liver wet weight,TG,FAS,ACCase and Malonyl-Co A levels were significantly decreased in geniposide group( P < 0. 01),while the AMPK activity in hepatic tissues was significantly increased( P < 0. 05),with improvement in visual and pathological performance.Compared with the model group,liver wet weight,fat weight,TG and FFA levels in hepatic tissues,and LDL-C level in serum were significantly decreased in Xuezhikang group( P < 0. 05). Compared with Xuezhikang group,the body weight of rat,fat weight and FFA level in hepatic tissues were significantly lower in geniposide group( P < 0. 01),but with no significant difference in other aspects. These findings indicated that geniposide was highly effective in improving the pharmacological effect of NAFLD induced by highfat diet,and the mechanism was achieved through AMPK-ACCase-Malonyl-Co A-FFA axis.国家自然科学基金项目(81274155;81503529);; 福建省自然科学基金项目(2014J01374);; 福建省高等学校新世纪人才计划项目;; 厦门市科技计划项目(3502Z20134020);; 福建省中医药科研项目(WZPW201308

    Comparison of uncut Roux-en-Y anastomosis and traditional Roux-en-Y anastomosis in the totally laparoscopic distal gastrectomy for gastric cancer: An analysis of multiple centers' data

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    目的对比非离断式(Uncut)Roux-en-Y吻合和传统Roux-en-Y吻合应用于全腹腔镜远端胃癌根治术后消化道重建的安全性和短期疗效。方法回顾性分析国内10家单位共60例远端胃癌根治术后全腹腔镜消化道重建的胃癌病人临床资料,根据消化道重建方式不同分为Uncut Roux-en-Y组(Uncut组)34例,传统Roux-enY组(传统组)26例。结果 Uncut Roux-en-Y吻合在消化道重建时间方面用时更短[(51.5±13.3)min vs.(80.4±16.2)min,P=0.000],出血量更少[(60.0±35.6)m L vs.(132.9±65.1)m L,P=0.000],且在进食半流饮食时间方面具有优势[(4.6±1.5)d vs.(7.2±2.3)d,P=0.000]。两组病人在留置胃管时间、术后排气时间、进食流质时间和术后住院时间方面差异无统计学意义。两组病人均无围手术期死亡病例,并发症发生率差异无统计学意义(8.8%vs.7.7%,P=0.875)结论 Uncut Roux-en-Y吻合和传统Roux-en-Y吻合应用于全腹腔镜下消化道重建安全可行,Uncut Roux-en-Y吻合在重建时间和控制出血量方面具有优势。Objective To compare the security and short-term effect of the digestive tract reconstruction during the totally laparoscopic distal gastrectomy for gastric cancer between the Uncut Roux-en-Y anastomosis and the traditional Roux- en- Y anastomosis. Methods The clinical data of 60 gastric cancer patients with digestive reconstruction underwent totally laparoscopic distal gastrectomy between December 2012 and June 2015 in 10 domestic hospital were analyzed retrospectively. According to the difference of digestive reconstruction,it can be divided into the Uncut Rouxen-Y anastomosis group with 34 patients and the traditional Roux-en-Y anastomosis group with 26 patients. Results In uncut Roux-en-Y anastomosis group,the operative time in digestive reconstruction was shorter[(51.5±13.3)min vs.(80.4±16.2)min,P=0.000]; the intraoperative blood loss was less[(60.0±35.6)m L vs.(132.9±65.1)m L,P=0.000];semi-liquid diet time was earlier[(4.6±1.5)d vs.(7.2±2.3)d,P=0.000]. However,there was no difference between the two groups on nasogastric tubegastrointestinaltwo groups on nasogastric tube,gastrointestinal transit,fluid diet and the duration of postoperative hospital stay. Both groups had no death case during the perioperative period and there was no significant statistical difference in the postoperative complication rates(8.8% vs. 7.7%,P=0.875).Conclusion The Uncut Roux- en- Y anastomosis and the traditional Roux-en-Y anastomosis are both safe and feasible for the digestive reconstruction under the totally laparoscopic distal gastrectomy for gastric cancer. Besides,the Uncut Roux- en- Yanastomosis has other advantages such as less reconstruction time and less bleeding.广东省科技计划项目(No.2014A020212591

    Data processing method of time-of-flight 3D imaging camera

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    飞行时间法三维成像摄像机测量结果存在中心点偏移、距离歧义性和混合像素等问题,且易受曝光时间和主动光源影响.为提高测量结果的有效性和准确性,对测量数据进行了如下处理:对摄像机进行校正,减小了球面距离到三维坐标转换过程中引入的误差;采用2个不同光源调制频率交替进行测量,根据2次测量结果差值消除距离歧义性;过度曝光时测量幅值随曝光时间增大而减小,据此提出了一种基于感兴趣区域的快速自动曝光控制方法;边界混合像素以单点或单线形式出现,根据某像素邻域内各像素位置分布情况判定该像素是否为混合像素;由测量幅值判定噪声大小,根据对主动光源成像时测量幅值很大、偏移值很小的特点辨别主动光源.实验结果表明:以上方法能有效提高数据可靠性和准确性.Measurement results of time-of-flight 3D imaging camera have problems of center offset,range ambiguity and mixed-pixel,and they are sensitive to exposure time and vulnerable to active light source.The measurement data were processed to improve the effectiveness and accuracy of measurement results.The camera was calibrated so that the error was decreased thanks to the transformation from spherical distances to Cartesian coordinates.The ambiguity was eliminated according to the difference between two measurements taken with two different light modulation frequencies alternately.The amplitude decreases with increasing exposure time due to excessive exposure,accordingly,a rapid auto-exposure control method based on region of interest was proposed.Boundary mixed pixels are in form of a single point or a single line,accordingly,the location distribution of each pixel in its neighborhood was a used to determine whether the pixel was a mixed pixel.Noise was determined according to the amplitude,meanwhile,the active light source was identified according to the characteristics that the amplitude was very small and the offset was very big when the active light source was measured.The experimental results showed that the data reliability and accuracy were improved with the above methods.国家自然科学基金重点资助项目(60534070);国家自然科学基金资助项目(60302013
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