213 resultados para 7140-243


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Well-dated, high-resolution records of planktonic foraminifera and oxygen isotopes from two sediment cores, A7 and E017, in the middle Okinawa Trough reveal strong and rapid millennial-scale climate changes since similar to 18 to 17 thousand years before present (kyr B.P.). Sedimentation rate shows a sudden drop at similar to 11.2 cal. kyr B.P. due to a rapid rise of sea level after the Younger Dryas (YD) and consequently submergence of the large continental shelf on the East China Sea (ECS) and the retreat of the estuary providing sediment to the basin. During the last deglaciation, the relative abundance of warm and cold species of planktonic foraminifera fluctuates strongly, consistent with the timing of sea surface temperature (SST) variations determined from Mg/Ca measurements of planktonic foraminifera from one of the two cores. These fluctuations are coeval with climate variation recorded in the Greenland ice cores and North Atlantic sediments, namely Heinrich event 1 (H1), Bolling-Allerod (B/A) and YD events. At about 9.4 kyr B.P., a sudden change in the relative abundance of shallow to deep planktonic species probably indicates a sudden strengthening of the Kuroshio Current in the Okinawa Trough, which was synchronous with a rapid sea-level rise at 9.5-9.2 kyr B.P. in the ECS, Yellow Sea (YS) and South China Sea (SCS). The abundance of planktonic foraminiferal species, together with Mg/Ca based SST, exhibits millennial-scale oscillations during the Holocene, with 7 cold events (at about 1.7, 2.3-4.6, 6.2, 7.3, 8.2, 9.6, 10.6 cal. kyr BP) superimposed on a Holocene warming trend. This Holocene trend, together with centennial-scale SST variations superimposed on the last deglacial trend, suggests that both high and low latitude influences affected the climatology of the Okinawa Trough. (c) 2006 Elsevier B.V. All rights reserved.

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本研究以双壳纲、翼形亚纲、珍珠贝目、扇贝超科的栉孔扇贝(Chlamys farreri )、海湾扇贝(Argopecten irradians)和牡蛎超科巨蛎属(Crassostrea)的长牡蛎(C. gigas)、葡萄牙牡蛎(C. angulata)、熊本牡蛎(C. sikamea)、香港巨牡蛎(C. hongkongensis)和近江牡蛎(C. ariakensis)5种牡蛎及异齿亚纲、帘蛤目、帘蛤科的紫斑文蛤(Meretrix pethechialis)为研究对象,系统的研究了以上物种的线粒体基因组全序列的特点。并以线粒体12个蛋白质编码基因的序列,在氨基酸和核苷酸水平上构建了软体动物的分子系统发生树。本研究旨在为利用线粒体基因组全序列全面构建软体动物分子系统发生树,为软体动物的系统发生和进化研究提供一种新的思路和前期基础工作,本研究主要内容分为以下三个部分: 一、栉孔扇贝和海湾扇贝线粒体基因组序列分析及分子系统发生研究 采用Long-PCR技术扩增了栉孔扇贝和海湾扇贝线粒体全基因组,利用步移法结合文库构建的测序策略获得了线粒体基因组的序列。海湾扇贝线粒体全基因组长度为16,211 bp,栉孔扇贝接近全序列长度为20,789 bp。两个基因组都编码35个基因,包括12个蛋白质编码基因,2个rRNA和21个tRNA。与典型的动物线粒体基因组相比,两个基因组都缺少一个蛋白质编码基因atp8和2个trnS, 在海湾扇贝基因组中有1个trnF的重复,而在栉孔扇贝基因组中有1个trnM的重复。基因排列比较显示,尽管海湾扇贝、栉孔扇贝和巨扇贝分类学上属于同一扇贝科,但是它们的线粒体基因排列非常不同。在四种扇贝中,虾夷扇贝与栉孔扇贝的基因排列顺序非常相似;即使排除tRNA的比较,栉孔扇贝和海湾扇贝基因组仅仅共享三个小的基因块;而海湾扇贝与巨扇贝仅有一个相同的基因块。在所有的系统发生分析中,四种扇贝稳定的系统发生关系得到强有力的支持,海湾扇贝较其他三种扇贝较早的分化出来;栉孔扇贝比其他两种扇贝与虾夷扇贝亲缘关系更近。贝叶斯法和最大似然法分析都支持扇贝超科的单系发生。 二、巨蛎属牡蛎线粒体基因组全序列分析及分子系统发生研究 采用Long-PCR扩增技术和步移法结合文库构建的技术策略获得了巨蛎属C. gigas、C. angulata、C. sikamea、C. hongkongensis和C. ariakensis 5种牡蛎线粒体全基因组序列,并于GenBank已公布的美洲牡蛎C.virginica序列进行比较研究。C. gigas、C. angulata、C. sikamea、C. hongkongensis和C. ariakensis线粒体全基因组长度分别为18,225 bp、18,225 bp、18,243 bp、18,622 bp和18,414 bp,都长于C. virginica基因组17,244 bp的长度。本研究的5种牡蛎线粒体基因组都编码39个基因,包括12个蛋白质编码基因,2个rRNA和25个tRNA。与典型的线粒体基因组相比,都缺少一个蛋白质编码基因atp8,有trnM、trnK和trnQ 3个tRNA基因的重复,更特别的是基因组中的rrnL分为两段,这在其它线粒体基因组中未见报道,有一个重复的rrnS;而C. virginica基因组编码37个基因,与其他牡蛎相比,没有trnK和trnQ重复,只有一个rrnS。基因排列比较显示,巨蛎属的5种牡蛎C. gigas、C. angulata、C. sikamea、C. hongkongensis和C. ariakensis基因排列完全一致,而与C. virginica的基因排列相比仍然有较大的差别,有多个tRNA发生易位。系统发生分析显示,C. gigas和C. angulata首先聚在一起,然后与C. sikamea聚为一支。C. hongkongensis和C. ariakensis聚成一支。C. virginica为单独的一支。系统树清楚的显示出C. gigas和C. angulata以及C. hongkongensis和C. ariakensis非常近的亲缘关系,这也是长期以来,牡蛎分类学上的经典问题,有学者认为C. gigas和C. angulata为同一物种,线粒体基因组的数据显示C. gigas和C. angulata可能达到不同物种的差异。传统分类上的“近江牡蛎”的“白蚝”和“赤蚝”,线粒体序列差别明显,完全支持两种牡蛎新种名的制定。 三、紫斑文蛤线粒体基因组全序列分析及分子系统发生研究 采用Long-PCR扩增技术和步移法结合文库构建的技术策略获得了紫斑文蛤线粒体基因组全序列。该基因组全长19,567 bp,编码36个基因,包括12个蛋白质编码基因,2个rRNA和22个tRNA。与典型的线粒体基因组相比,缺少一个蛋白质编码基因atp8和1个trnS, 有1个trnQ基因的重复。基因排列比较显示,双壳类的基因排列在低的分类阶元时相对保守。在帘蛤科中,紫斑文蛤M. petechialis和菲律宾蛤仔V. philippinarum共享四个完全一致的基因块,两个大的基因块是cox1-L1-nad1-nad2-nad4L-I 和 cox2-P-cob-rrnL-nad4-H-E-S2-atp6-nad3-nad5,另两个小基因块只包括tRNA基因。在以氨基酸序列构建的分子系统树中,帘蛤科紫斑文蛤与菲律宾蛤仔首先聚在一起,然后,它们与A. tuberculata形成一个进化枝。这一枝与H. arctica结合起来,支持异齿亚纲单系发生。

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Aestivation is an indispensable state in the life history of sea cucumbers, Apostichopus japonicus. The immune characteristics of the coelomic fluid of A. japonicus, were investigated during aestivation. Samples were collected between July and November 2006 from a coastal pond located off the Yellow Sea in Jiaonan, Shandong Province, China. The total coelomocytes counts (TCC), total superoxide dismutase (T-SOD), catalase (CAT), myeloperoxidase (MPO), and lysozyme (IZM) in the coelomic fluid were measured. The activities of catecholamines, [adrenaline (AD), noradrenaline (NA), and dopamine (DOP)] were estimated. TCC decreased from July to September, indicating weakness of the cellular immune activity at that time. Activities of SOD, CAT, MPO, and LZM changed significantly from July to October. Catecholamines AD and NA in coelomic fluid were significantly higher on August 21 and November 27. There was no significant variation in DOP during the sampling period. Thus, immune characters in coelomic fluid of A. japonicus changed significantly during aestivation. Water temperature was significantly and negatively correlated with TCC, and salinity was significantly and positively correlated with AD and NA. The mechanism of aestivation in A. japonicus is complex and might not be attributed only to environmental changes, such as temperature and salinity, as shown in previous studies. (C) 2008 Elsevier B.V. All rights reserved.

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The modulation of carrageenan oligosaccharides from Kappaphycus striatum on the immune system in S 180-bearing mice was investigated. The mice inoculated with S180 cell suspension were treated p.o. with carrageenan oligosaccharides (50, 100 and 200 mu g/g) for 14 days. The effects of carrageenan oligosaccharides on transplantable tumors and macrophage phagocytosis, quantitative hemolysis of sheep red blood cells (QHS),. lymphocyte proliferation, the activity of natural killer cells (NK), production of interleukin-2 (IL-2) and tumor necrosis factor-alpha (TNF-alpha) were studied. Carrageenan oligosaccharides could significantly inhibit the growth of transplantable sarcoma S180 and increase macrophage phagocytosis, the form of antibody secreted by spleen cells, spleen lymphocyte proliferation, NK cells activity, serumal IL-2 and TNF-alpha level in S 180-bearing mice. Considering all these results, it is suggested that carrageenan oligosaccharides exert their antitumor effect by promoting the immune system. (c) 2005 Elsevier Ireland Ltd. All rights reserved.

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The impact of starvation on larvae of Ivory shell Babylonia formosae habei was studied in a laboratory experiment. Newly hatched veligers showed considerable tolerance to starvation due to their endogenous yolk material, and time to the point-of-no-return (PNR; the threshold point during starvation after which larvae can longer metamorphose even if food is provided) was calculated to be 104.5 h. However, starvation still affected larval growth, survival, and metamorphosis. Mean shell length of larvae increased 49.77 mum day(-1) for nonstarved, but only 11.13 mum day (-1) for larvae starved for 108 h. After larvae began feeding, their growth rates rapidly recovered to the level of the nonstarved following short periods of starvation (less than 48 h), but were inhibited and unable to ever reach the level of the nonstarved when being starved beyond 48 h. Percent metamorphosis was 53.75% for the nonstarved, but all larvae died before 10 days for those starved for 108 h. Starvation not only affected larval time to reach metamorphosis, but also caused the delay in the time to metamorphosis. For the nonstarved, larvae took only 11.5 days to reach spontaneous metamorphosis, but they took 20 days to reach spontaneous metamorphosis when starved for 96 h, and this duration of delayed metamorphosis reached 8.5 days. Furthermore, the importance of yolk material for maintaining larval survival of B. formosae habei during starvation periods is also discussed. (C) 2004 Elsevier B.V. All rights reserved.

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为研究亲子分开后雌性根田鼠对亲本气味的记忆持续时间,分别在未分开(20日龄)、分开10d(30日龄)、20d(40日龄)、30d(50日龄)、40d(60日龄)时,以新鲜尿作气味源,在行为观察箱中记录雌性根田鼠对不同气味源的行为响应模式,结果表明:(1)未分开时,雌鼠遭遇父本气味时自我修饰的频次极显著高于陌生雄鼠气味,在分开10d时,雌鼠接近父本气味的频次显著多于接近陌生雄鼠气味的频次,其对前者反标记显著少于后者;(2)分开20d后,雌鼠对父本和陌生雄鼠气味的行为响应无明显差异;(3)未分窝时,雌性根田鼠幼仔对母本和陌生雌鼠气味的行为响应无差异;(4)分开10-40d时,雌性根田鼠对母本和陌生雌鼠气味表现出不同的行为响应模式。以上结果表明,在亲子分开10d时,雌鼠仍能识别父本和陌生雄鼠的气味;分开20d后,雌鼠不再能够识别父本和陌生雄鼠的气味;在亲子分开40d时,雌鼠仍能识别母本和陌生雌鼠的气味。因此,雌鼠对父本气味的嗅觉记忆时间可以持续到亲子分开10-20d之间;而对母本气味的嗅觉记忆时间则可以持续到亲子分开40d以上。

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Potentilla fruticosa scrub, Kobresia humilis meadow and Kobresia tibetica meadow are widely distributed on the Qinghai-Tibet Plateau. During the grass exuberance period from 3 July to 4September, based on close chamber-GC method, a study on CO2 emissions from different treatments was conducted in these meadows at Haibei research station, CAS. Results indicated that mean CO2emission rates from various treatments were 672.09+152.37 mgm-2h-1 for FC (grass treatment); 425.41+191.99 mgrn-2h-1 for FJ (grass exclusion treatment); 280.36+174.83 mgrn-2h-1 for FL (grass and roots exclusion treatment); 838.95+237.02 mgm-2h-1 for GG (scrub+grass treatment); 528.48+205.67 mgm-2h-1for GC (grass treatment); 268.97 ±99.72 mgm-2h-1 for GL (grass and roots exclusion treatment); and 659.20±94.83 mgm-2h-1 for LC (grass treatment), respectively (FC, FJ, FL, GG, GC, GL, LC were the Chinese abbreviation for various treatments). Furthermore, Kobresia humilis meadow, Potentilla fruticosa scrub meadow and Kobresia tibetica meadow differed greatly in average CO2 emission rate of soil-plant system, in the order of GG>FC>LC>GC. Moreover, in Kobresia humilis meadow,heterotrophic and autotrophic respiration accounted for 42% and 58% of the total respiration of soil-plant system respectively, whereas, in Potentilla fruticosa scrub meadow, heterotrophic and autotrophic respiration accounted for 32% and 68% of total system respiration from G-G; 49% and 51%from GC. In addition, root respiration from Kobresia humilis meadow approximated 145 mgCO2m-2h-1,contributed 34% to soil respiration. During the experiment period, Kobresia humilis meadow and Potentilla fruticosa scrub meadow had a net carbon fixation of 111.11 grn-2 and 243.89 grn-2,respectively. Results also showed that soil temperature was the main factor which influenced CO2 emission from alpine meadow ecosystem, significant correlations were found between soil temperature at 5 cm depth and CO2 emission from GG, GC, FC and FJ treatments. In addition, soil moisture may be the inhibitory factor of CO2 emission from Kobresia tibetica meadow, and more detailed analyses should be done in further research.

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分析了40a海北高寒温地区域气候变化特征,以及近期温地退化和值被演替的情况,结果表明:祁连山海北地区自1957年以来平均气温以0.157℃.10a~-1的倾向率升高,年降水量约以18.59mm.10a~-1的倾向率减,年平均地温比同期气温的增加更为迅速,表现出海北地区气候及土壤性状匀向干暖化趋势发展,特别是土壤干暖化程度尤为明显.由于人类活动加剧影响,超载过牧,原生植被遭受破坏,草场退化严重,地表潜的蒸散力加大,深层的多年冻土退化,冻胀草丘坍塌,导致温地植被 发生变化,使沼泽化草甸向典型草甸演替,不同年度调查结果表明,高寒湿地植被在气候干暖化趋势的加剧影响下,植物群落组成发生变异,物种多样性、生态优 势度均比湿地原生植被的物种有增多的趋势.原生适应寒冷潮湿生境的藏嵩草为主的草甸植被类型逐渐退化,有些物种甚至消失,而被那些寒冷湿中生为主要典型草甸类型所替代.组成植物群落的湿中生种类减少,中生种类(如线叶嵩草)大量增加,群落盖度相对降低,群落生产量大幅度下降。

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A pre-column derivatization method for the sensitive determination of amines using a labeling reagent 2-(11H-benzo[a]-carbazol-11-yl) ethyl chloroformate (BCEC-Cl) followed by high-performance, liquid chromatography with fluorescence detection has been developed. Identification of derivatives was carried out by LC/APCI/MS in positive-ion mode. The chromophore of 1,2-benzo-3,4-dihydrocarbazole-9-ethyl chloroformate (BCEOC-Cl) reagent was replaced by 2-(11H-benzo[a]-carbazol-11-yl) ethyl functional group, which resulted in a sensitive fluorescence derivatizing reagent BCEC-Cl. BCEC-Cl could easily and quickly label amines. Derivatives were stable enough to be efficiently analyzed by HPLC and showed an intense protonated molecular ion corresponding m/z [M+ H](+) under APCI/MS in positive-ion mode. The collision-induced dissociation of the protonated molecular ion formed characteristic fragment ions at m/z 261.8 and m/z 243.8 corresponding to the cleavages of CH2O-CO and CH2-OCO bonds. Studies on derivatization demonstrated excellent derivative yields over the pH 9.0-10.0. Maximal yields close to 100% were observed with three- to four-fold molar reagent excess. In addition, the detection responses for BCEC-derivatives were compared to those obtained using 1,2-benzo-3,4-dihydrocarbazole-9-ethyl chloroformate (BCEOC-Cl) and 9-fluorenyl methylchloroformate, (FMOC-Cl) as labeling reagents. The ratios I-BCEC/I-BCEOC = 1.94-2.17 and I-BCEC/I-FMOC = 1.04-2.19 for fluorescent (FL) responses (here, I was relative fluorescence intensity). Separation of the derivatized amines had been optimized on reversed-phase Eclipse XDB-C-8 column. Detection limits calculated from 0.50 pmol injection, at a signal-to-noise ratio of 3, were 1.77-14.4 fmol. The relative standard deviations for within-day determination (n = 11) were 1.84-2.89% for the tested amines. The mean intra- and inter-assay precision for all amines levels were < 3.64% and 2.52%, respectively. The mean recoveries ranged from 96.6% to 107.1% with their standard deviations in the range of 0.8-2.7. Excellent linear responses were observed with coefficients of > 0.9996. (C) 2006 Elsevier B.V. All rights reserved.

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A highly sensitive and accurate method based on the precolumn derivatization of bile acids (BA) with a high ionization efficiency labeling reagent 1,2-benzo-3,4-dihydrocarbazole-9-ethyl-benzenesulfonate (BDEBS) coupled with LC/MS has been developed. After derivatization, BA molecules introduced a weak basic nitrogen atom into the molecular core structure that was readily ionized in commonly used acidic HPLC mobile phases. Derivatives were sufficiently stable to be efficiently analyzed by atmospheric pressure chemical ionization (APCI)-MS/MS in positive-ion mode. The MS/MS spectra of BA derivatives showed an intense protonated molecular ion at m/z [M + H](+). The collision-induced dissociation of the molecular ion produced fragment ions at [MH - H2O](+), [MH - 2H(2)O](+), [MH - 3H(2)O](+). The characteristic fragment ions were at m/z 320.8, 262.8, and 243.7 corresponding to a cleavage of N - CO, O - CO, and C - OCC, respectively, and bonds of derivatized molecules. The selected reaction monitoring, based on the m/z [M + H]+ -> [MH - H2O](+), [MH - H2O](+), [MH - 2H(2)O](+), [MH-3H(2)O](+), 320.8, 262.8, and 243.7 transitions, was highly specific for the BA derivatives. The LODs for APCI in a positive-ion mode, at an S/N of 5, were 44.36-153.6 fmol. The validation results showed high accuracy in the range of 93-107% and the mean interday precision for all standards was < 15% at broad linear dynamic ranges (0.0244-25nmol/mL). Good linear responses were observed with coefficients of > 0.9935 in APCI/MS detection. Therefore, the facile BDEBS derivatization coupled with mass spectrometric analysis allowed the development of a highly sensitive and specific method for the quantitation of trace levels of the free and glycine-conjugated BA from human serum samples.

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Grazing intensity may alter the soil respiration rate in grassland ecosystems. The objectives of our study were to (1) determine the influence of grazing intensity on temporal variations in soil respiration of an alpine meadow on the northeastern Tibetan Plateau; and (2) characterise, the temperature response of soil respiration under different grazing intensities. Diurnal and seasonal soil respiration rates were measured for two alpine meadow sites with different grazing intensities. The light grazing (LG) meadow site had a grazing intensity of 2.55 sheep ha(-1), while the grazing intensity of the heavy grazing (HG) meadow site, 5.35 sheep ha(-1), was approximately twice that of the LG site. Soil respiration measurements - showed that CO2 efflux was almost twice as great at the LG site as at the HG site during the growing season, but the diurnal and seasonal patterns of soil respiration rate were similar for the two sites. Both exhibited the highest annual soil respiration rate in mid-August and the lowest in January. Soil respiration rate was highly dependent on soil temperature. The Q(10) value for annual soil respiration was lower for the HG site (2.75) than for the LG site (3.22). Estimates of net ecosystem CO2 exchange from monthly measurements of biomass and soil respiration revealed that during the period from May 1998 to April 1999, the LG site released 2040 g CO2 m(-2) y(-1) to the atmosphere, which was about one third more than the 1530g CO2 m(-2) y(-1) released at the HG site. The results suggest that (1) grazing intensity alters not only soil respiration rate, but also the temperature dependence of soil CO2 efflux; and (2) soil temperature is the major environmental factor controlling the temporal variation of soil respiration rate in the alpine meadow ecosystem. (C) 2003 Elsevier Ltd. All fights reserved.

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机器人化柔性装配单元是柔性制造系统的重要组成部分.本文在介绍机器人化柔性装配单元组成及特点的基础上,建立了机器人化柔性装配单元的广义随机Petri网,并进行了SiMPLE++仿真,提出了将广义随机Petri网与面向对象的仿真技术相结合用于装配过程建模与仿真的方法。

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本论文的研究内容是围绕国家“863”计划支持项目“基于探测机器人技术的反恐立体侦察监控示范系统”(编号:2004AA420110)和“微小型反恐侦察移动平台和探测关键技术研究”(编号:2005AA420230)展开的。研究工作以微小型壁面移动机器人的研制为实际背景,主要包括以下五个方面的内容:⑴ 机器人的运动学、动力学分析和控制系统设计;⑵ 机器人的运动步态分析;⑶ 机器人在狭窄空间中的运动规划方法研究,以及在壁面过渡时的运动规划方法研究;⑷ 欠平滑壁面上机器人的自主行为控制和针对动力学特性的重力补偿控制研究;⑸ 论文所提出方法的仿真分析和实验研究。 第一,介绍了微小型壁面移动机器人的欠驱动机构设计和三种运动模式;分别基于D-H坐标变换和拉格朗日方法,对机器人的运动学和动力学特性进行了分析,为接下来的步态分析、运动规划和控制研究奠定了基础;开发了微小型壁面移动机器人的嵌入式DSP控制系统,为论文中的仿真和实验研究提供了物理平台。 第二,对尺蠖的生物特征和运动机制进行了简要介绍,并总结了尺蠖运动的特点;通过理论计算和实验测试,分析了微小型壁面移动机器人的步行稳定性;在机构设计和运动学建模基础上,全面地分析了微小型壁面移动机器人的各种基本步态、派生步态和壁面过渡步态,同时引入用以描述步态之间转换关系的步态算子,为后续的运动规划和控制方法研究做好了理论铺垫。 第三,分析了微小型壁面移动机器人运动规划问题的特殊性;考虑到机器人运动时真空吸附的耗时问题和狭窄空间中步态选择的合理性,通过对局部动态窗口法进行改进,引入可达空间动态局部栅格和遍历搜索算法,提出了基于可行步态的微小型壁面移动机器人在狭窄空间中的运动规划方法;根据壁面过渡的步态分析结果,并考虑到吸盘足的真空吸附载荷和机器人的动力学特性,提出了基于步态参数规划与最小能耗轨迹优化相结合的微小型壁面移动机器人在壁面过渡时的运动规划方法。通过仿真分析和实验研究,验证了上述运动规划方法的合理性和有效性。 第四,针对欠平滑壁面上机器人吸盘足吸附失败时的自主行为控制问题,根据步态分析结果,建立了吸盘足的有限状态机模型,并按“就近”原则设定状态转移优先级,提出了基于有序试探的微小型壁面移动机器人着地点选择控制方法;针对机器人的动力学特性,特别是重力矩变化对机器人运动控制的影响,在采用模糊自适应PID控制的基础上,根据轨迹优化结果,引入前馈重力补偿环节,提出了基于重力补偿的微小型壁面移动机器人模糊自适应PID控制方法。通过仿真分析和实验研究,验证了所提方法在改善系统控制性能,提高机器人自主能力方面的可行性和有效性。 第五,在武警北京特警学院的反劫机训练场,对微小型壁面移动机器人的运动控制能力和越障能力进行了现场实验测试,验证了论文所提出运动规划和控制方法在实际应用中的有效性。

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低镁方解石腕足化石壳体被广泛地应用于地质历史时期原始海洋地球化学组成的重建研究,其保存度的识别是该研究的一项重要内容。通常使用显微结构、阴极发光和微量元素含量等3 种方法验证其对原始地球化学信息的保存,微量元素含量的识别方法一直被置于较为次要的地位。我们对采自广西六景泥盆系腕足化石微量元素研究表明,其Fe 、Mn、Sr 分别为(12~2800) ×10 - 6 、(1~711) ×10 - 6和(243~1835) ×10 - 6 。上述3 种识别方法实质上都是微量元素的识别,其余两种识别方法只是微量元素的不同表现而已。通过氧同位素组成、Mn 和Sr/ Mn 对比,得知Mn 含量小于100 ×10 - 6 ,Sr/ Mn 值高于10的腕足化石壳体基本上保存完好。这一发现为利用腕足化石研究海水原始碳氧同位素提供了有力的判据。

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选择和使用合适的示踪指标,是揭示岩溶地区红色风化壳物质来源的关键。粒度参数在古环境研究中被大家广泛采用,但是在风化壳物源示踪方面还是新的尝试,尤其在我国。本文选择贵州中部平坝县3个下伏基岩为白云岩的缺失原岩结构的红色风化壳剖面,通过基岩酸不溶物和剖面的粒度分析,表明红色风化壳物质对下伏基岩有很好的继承性。粒度参数随剖面深度呈规律变化,指示了标准残积风化壳的发育特征。