Large-payload climbing in complex vertical environments using thermoplastic adhesive bonds

Despite many approaches proposed in the past, robotic climbing in a complex vertical environment is still a big challenge. We present here an alternative climbing technology that is based on thermoplastic adhesive (TPA) bonds. The approach has a great advantage because of its large payload capacity and viability to a wide range of flat surfaces and complex vertical terrains. The large payload capacity comes from a physical process of thermal bonding, while the wide applicability benefits from rheological properties of TPAs at higher temperatures and intermolecular forces between TPAs and adherends when being cooled down. A particular type of TPA has been used in combination with two robotic platforms, featuring different foot designs, including heating/cooling methods and construction of footpads. Various experiments have been conducted to quantitatively assess different aspects of the approach. Results show that an exceptionally high ratio of 500% between dynamic payloads and body mass can be achieved for stable and repeatable vertical climbing on flat surfaces at a low speed. Assessments on four types of typical complex vertical terrains with a measure, i.e., terrain shape index ranging from -0.114 to 0.167, return a universal success rate of 80%-100%. © 2004-2012 IEEE.

Study on optical properties of Er/Er+O doped GaN thin films

We extend the use of Raman spectroscopy to investigate the modes of Er-implanted and Er + O co-implanted GaN, and discuss the influence of O ions on Er3+ -related infrared photoluminescence (PL). It is found that Er3+ implantation introduces new Raman peaks in Raman spectra at frequencies 300 and 670 cm and one additional new peak at 360cm is introduced after Er + O implantation. It is proposed that the broad structure around 300 cm(-1) mode originates from disorder-activated scattering (DARS). The Raman peak at 670 cm is assigned to nitrogen vacancy related defects. The 360 cm peak is attributed to the O implantation induced defect complexes (vacancies, interstitial, or anti-sites in the host). The appearance of the 360 cm(-1) mode results in the decrease of the Er3+ -related infrared PL of GaN: Er + O.

一种面向异构实时集群系统的使用率反馈控制方法

软实时系统有着广泛的应用,如在线游戏、股票交易、传感器网络数据处理等.在这类应用中,通常有多个服务节点来响应外界大量的软实时请求.为了保证服务质量及防止系统超载,这些节点的CPU需要满足一定的使用率限制.为此,首先提出了异构集群系统中基于负载平衡的CPU使用率动态模型,其次在算法设计上将反馈控制理论引入其中并提出了针对异构实时集群系统的基于反馈的使用率控制算法.实验结果证明,该算法在引入负载平衡机制的异构实时集群系统中运行良好,系统节点间负载均衡并且各节点的CPU使用率能稳定地运行在限定状态.

掺Er/Er+O的GaN薄膜光学性质的研究

利用Raman散射谱研究了GaN注Er以及Er+O共注样品的振动模，并讨论了共注入O对Er离子发光的影响. 在Raman散射谱中，对于注Er的GaN样品出现了300 cm~(-1)和670 cm~(-1)两个新的Raman峰，而对于Er+O共注样品，除了上述两个峰外，在360 cm~(-1)处出现了另外一个新的峰，其中300 cm~(-1)峰可以用disorder-activated Raman scattering (DARS)来解释，670 cm~(-1)峰是由于与N空位相关的缺陷引起的，而360 cm~(-1)峰是由O注入引起的缺陷络合物产生的. 由于360 cm~(-1)模的缺陷出现，从而导致Er+O共注入GaN薄膜红外光致发光(PL)强度的下降

Preparation and characterization of erbium doped sol-gel silica glasses

Erbium-doped silica glasses were made by sol-gel process. Intensive photoluminescence (PL) spectra from the Er-doped silica glasses at room temperature were measured. A broadband peak at 1535 ma, corresponding to the I-4(13/2)-I-4(15/2) transition, its full width at half-maximum (FWHM) of 10 nm, and a shoulder at 1546 nm in the PL spectra were observed. At lower temperatures, main line of 1535 nm and another line of 1552 Mn instead of 1546 nm appear. So two types of luminescence centers must exist in the samples at different temperature. The intensity of main line does not decrease obviously with increasing temperature. By varying the Er ion concentration in the range of 0.2 wt% - 5wt%, the highest photoluminescence intensity was obtained at 0.2wt% erbium doped concentration. Luminescence intensity decreases with increasing erbium concentration. Cooperative upconversion was used to explain the concentration quenching of luminescence from silica glass with high erbium concentration. Extended X-ray absorption fine structure measurements were carried out. It was found that the majority of the erbium impurities in the glasses have a local structure of eight first neighbor oxygen atoms at a mean distance of 0.255 nm, which is consistent with the typical coordination structure of rare earth ion.

地衣芽孢杆菌GXN151纤维素酶基因的克隆与表达

从广西大学农场陈旧稻草堆、甘蔗渣堆、龙胜温泉等地采集不同的土样和水样，从中共分离到10株能降解结晶纤维素的细菌、放线菌和真菌，对它们的165RNA或185 rRNA基因序列进行了分析，其中从稻草堆中分离到的好氧细菌GXN 151具有耐中温、生长迅速、能降解天然纤维素的特点。运用生理生化和电镜观察进一步将其鉴定为地衣芽抱杆菌。用pUC18和pBluescript KS＋作载体，分别以CoR工和品u3AI部分酶切的GXN 151的总DNA作目的片段，在大肠杆菌中构建了地衣芽抱杆菌GXN151的2个基因文库。运用含狡甲基纤维素的平板筛选法，从GXN151的基因文库中共筛选到14个表达梭甲基纤维素酶（CMCase）活性的克隆，采用酶切分析、亚克隆、Southern杂交、DNA测序分析将这些克隆划分为3类不重叠克隆群。pGxNLI、pGXNLZ、pGxNL7、pGxNP12和pGxNPI～pGXNP6共10个克隆归为一类重叠克隆，测序分析了PGXNLZ的序列，其长度为3672bP，其上含有一个完整的长1626 bp的ORF（GenBonk索引号为AY291583），可编码一个含542个氨基酸的内切葡聚糖酶Ce15A，其预计分子量为59，625D娜Ce15A含有家族5糖基水解酶催化功能域和家族3碳水化合物结合组件（CBM3）。PCR 扩增了ceJSA的编码框并将其克隆到大肠杆菌表达载体pET-30a（＋）上，酶谱分析表明该基因在大肠杆菌JM109（DE3）和BL21（DE3） pLysS中均表达出具梭甲基纤维素酶活性的蛋白质产物。克隆pGxNLg测序共得5818bp，pGxNLg序列中含有一个完整的内切葡聚糖酶基因cel12A（GenBaok索引号为AY291066）和一个外切-Q-葡萄糖营酶基因amyA，cel12A长783 bp，可编码含261个氨基酸的蛋白质，预计分子量为29，035 Da，含有一个家族12糖基水解酶催化功能域。amyA为1680bP，推断其编码含560个氨基酸的蛋白质，预计分子量为65，121 Da。PCR扩增了cel12A基因的含催化功能域编码区的DNA序列并连接到表达载体pET30a（＋）上得表达质粒pGxN12A，pGXN 12A在大肠杆菌JM1O9（DE3）和BL21（DE3）pLysS中均J高效表达，并对表达条件进行了研究。克隆pGXNLS、pGXNPS和pGXNpn为一类重叠克隆，测序表明pGxNPll克隆的序列共为3406bP，它包括了一个完整的内切葡聚糖酶基因ce19A和一个不完整的纤维二糖水解酶基因ce148A，ce19A基因由1899bP组成，可编码一个含633个氨基酸的蛋白质，预计分子量为71，240Da。ce19A基因的产物Ce19A含有一个家族9糖基水解酶催化功能域和一个家族3碳水化合物结合组件（CBM3）。Ce148A属于糖基水解酶第4S家族，DNA杂交表明cel48A基因的未被克隆的下游序列位于一个约10kb的SaLI片段或4kb的EcoRI片段上。