Pattern formation in a confined polymer film induced by a temperature gradient

We have studied a morphological instability of a double layer comprising the polymer film and air gap confined between the two plates set to different temperatures. The temperature gradient across the double layer causes the breakup of the polymer film into well-defined columnar, striped or spiral structures spanning the two plates. The pattern formation mechanisms have been discussed. The formed patterns can be transferred to produce PDMS stamp, a key element of soft lithography for future microfabrication.

Determination of biogenic amines by capillary electrophoresis with pulsed amperometric detection

The biogenic amines, putrescine, cadaverine, spermidine and spermine were separated and quantified by capillary electrophoresis with pulsed amperometric detection. Detection potential of the pulsed amperometric detection was optimized as 0.6 V Optimal separation of the biogenic amines was achieved using a separation buffer of 30 mM citrate at pH 3.5, while keeping the buffer in the detection cell as 20 mM NaOH. Using these conditions, the four biogenic amines were baseline separated. Extrapolated limits of detection for putrescine, cadaverime, spermidine and spermine were 400, 200, 100 and 400 nM for the standard mixture (polyamines dissolved in running buffer), respectively. These are lower than ultraviolet detection and comparable or even lower than laser-induced fluorescence detection results as reported in the literature. The number of theoretical plates was maintained at the 105 level, which is absolutely higher than any reported method. When applying capillary electrophoresis-pulsed amperometric detection to milk analysis, only spermidine was found in amounts varying between 0.1 and 0.5 mg/kg.

Chiral separation of promethazine by capillary electrophoresis with end-column amperometric detection

Sensitive end-column amperometric detection has been successfully coupled to capillary electrophoresis for chiral separation of promethazine, with a carbon fiber microdisk electrode as working electrode. Baseline separation and sensitive detection were achieved under optimum conditions: 0.030 M Na2HPO4 and 0.015 M citric acid at pH = 2.50, 1.0 mM beta -CD, 10 kV separation voltage, and detection potential 1.10 V (vs Ag/AgCl). The numbers of theoretical plates were higher than 700000, and the detection limit was 5 x 10(-8) M. On-line treatment of the electrode has also been studied and discussed.

End-column amperometric detection of aesculin and aesculetin by capillary electrophoresis

Determination of aesculin (AL) and aesculetin (AT) by capillary electrophoresis with end-column amperometric detection using a 33 mu m microdisk carbon fiber electrode is described. The HDVs, the effect of pH, buffer concentration, injection voltage, injection time and separation voltage on the peak current response (i(p)) of the analytes and the number of theoretical plates (N) were studied. The method has high sensitivity and good reproducibility. Under the optimum condition - 10 mM, pH 9.00 phosphate buffer, 4 s at 9 kV injection, separation at 15 kV and +1.0 V as the detection potential - low detection limits (S/N = 3) of 0.06 and 0.3 mu M were obtained for AL and AT, respectively. The calibration curve was linear over three orders of magnitude. The relative standard deviations (n = 15) of peak current and migration time were 3.9% and 4.6%, and 0.96% and 0.75% for 15 consecutive injections of 5 mu M AL and AT, respectively. The use of this method for the separation and detection of the two compounds present in the traditional Chinese medicine and human urine samples is also reported. (C) 1999 Elsevier Science B.V. All rights reserved.

Separation of phenothiazines using aqueous and nonaqueous capillary electrophoresis

Separations of phenothiazines, promethazine(PZ), dioxypromethazine (OZ), chlorpromazine(CZ), trifluoperazine(TfZ) and thioridazine(TZ) by capillary electrophoresis in water and FA media were carried out and compared. Thus different selectivity and resolution were observed as media varying from water to FA. Migration order was PZ, OZ, CZ and TZ in water but (TZ+PZ), CZ and OZ in FA, when the same buffer, 25 mmol/L Tris and 25 mmol/L citric acid, was used. It also has been observed that pH has great effect on selectivity both in water and FA and a possible explanation was given. Separation efficiency was higher in FA media than in water because of the permission of high voltage applied. For all separations in FA 30 kV was applied, and when 25 mmol/L Tris was used as buffer, current was only 20 mu A and complete separation of TZ, CZ, PZ and OZ was achieved with effencicy higher than 3.5 x 10(5) theoretical plates for all analytes. The high performance of capillary electrophoresis in FA suggests that FA is an excellent media separation.

Determination of sulfadiazine and sulfamethoxazole by capillary electrophoresis with end-column electrochemical detection

Capillary electrophoresis (CE) with end-column electrochemical detection (EC) of sulfadiazine (SDZ) and sulfamethoxazole (SMZ) is described. Under the optimum conditions, SDZ and SMZ were separated satisfactorily, and a highly sensitive and stable response was obtained at a potential of 1.1 V versus Ag/AgCl. Optimized end-column detection provides detection limits as low as 0.1 mu M for both compounds, which corresponds to 0.024 and 0.021 fmol with peak efficiencies of 394000 and 335000 theoretical plates for SDZ arid SMZ, respectively. The calibration graph was linear over three orders of magnitude. The relative standard deviations (n = 12) of peak currents and migration times were 2.3 and 2.7%, and 0.8 and 1.3%, respectively, for the two compounds. The proposed method was applied to the analysis of tablets and human urine samples with satisfactory results.

Construction and characterization of two bacterial artificial chromosome libraries of Zhikong scallop, Chlamys farreri Jones et Preston, and identification of BAC clones containing the genes involved in its innate immune system

Large-insert bacterial artificial chromosome (BAC) libraries are necessary for advanced genetics and genomics research. To facilitate gene cloning and characterization, genome analysis, and physical mapping of scallop, two BAC libraries were constructed from nuclear DNA of Zhikong scallop, Chlamys farreri Jones et Preston. The libraries were constructed in the BamHI and MboI sites of the vector pECBAC1, respectively. The BamHI library consists of 73,728 clones, and approximately 99% of the clones contain scallop nuclear DNA inserts with an average size of 110 kb, covering 8.0x haploid genome equivalents. Similarly, the MboI library consists of 7680 clones, with an average insert of 145 kb and no insert-empty clones, thus providing a genome coverage of 1.1x. The combined libraries collectively contain a total of 81,408 BAC clones arrayed in 212 384-well microtiter plates, representing 9.1x haploid genome equivalents and having a probability of greater than 99% of discovering at least one positive clone with a single-copy sequence. High-density clone filters prepared from a subset of the two libraries were screened with nine pairs of Overgos designed from the cDNA or DNA sequences of six genes involved in the innate immune system of mollusks. Positive clones were identified for every gene, with an average of 5.3 BAC clones per gene probe. These results suggest that the two scallop BAC libraries provide useful tools for gene cloning, genome physical mapping, and large-scale sequencing in the species.

Evidences of the intertidal red alga Grateloupia turuturu in turning Vibrio parahaemolyticus into non-culturable state in the presence of light

Grateloupia turuturu, previously known as Grateloupia doryphora, has been widely reported to be an invasive algal species. There are no studies to relate the impact of its existence on its surrounding environment. In this paper, we present our results to show that about 70% of individuals collected from the field could turn Vibrio parahaemolyticus into non-culturable state on both selective (TCBS) and non-selective (2216E) culture medium in 24 h in the presence of light in live algal culture. Total bacteria counts on TCBS and 2216E plates dropped from the initial 565 (174) and 1192 (60) cfu ml(-1) respectively to zero in 24 h. This effect disappeared when the alga was grown in darkness. The same effect was not found in two other intertidal macroalgae Laminaria japonica and Palmaria palmata. Further tests showed that the settlement ability of bacteria in seawater was impaired significantly in the presence of this alga in comparison with three other algal species. (c) 2006 Elsevier B.V. All rights reserved.

Settling abalone veliger larvae in a free-swimming microalgal culture

In the current abalone hatchery in China, insufficient diatoms on vertically placed corrugated pvc plates at later stage often could not support the growth of postlarvae up to the stage that they can feed on live macroalgae. As a result, stripping the spats (35 mm) off by anaesthetization and switching the diet from live diatoms to artificial powdered diet in combination has to be performed in most of the abalone farms. This manipulation normally leads to more than 50% mortality. Here we report the direct use of the unicellular green alga Platymonas helgolandica Kylin var. tsingtaoensis as a potential alga to be used to settle the veliger larvae of the Pacific abalone Haliotis discus hannai and to feed the postlarvae. Settlement rate of 2-day-old veliger larvae in mono culture of P helgolandica could be as high as 92% ( +/- 4.2%) on day 10 in small scale trials, higher than that in the selected benthic diatom strain (53.6% +/- 12.7%) when settled in the water in which bacteria propagation was controlled by treatment of 2 ppm of benzylpenicillinum calcium and streptomycin sulfate. Postlarvae fed solely on P. helgolandica or the selected benthic diatom Navicula-2005-A grew at rates of 40.1 ( +/- 1.9) and 45.8 (+/- 13.4) mu m day(-1), respectively, when raised at 22 degrees C until day 50 postfertilization. P. helgolandica was shown to have distinct diurnal settling rhythm characterized with a peak of settled cells in the middle of the night for cell division and a peak of free-swimming cells in the middle of the day. High density of attached P. helgolandica cells on the inner surface of the culture facility in the night fits the nocturnal feeding behavior of the abalone spats. Judged by the promising larvae settling rate, growth and survival rates of the postlarvae fed with this alga, the free-swimming micro-green alga P. helgolandica constitutes a potential species for settling the veliger larvae and for supporting the growth of postlarvae as well. (c) 2006 Published by Elsevier B.V.

三种海水经济鱼类早期发育生物学的研究

海水经济鱼类的养殖在我国已经形成第四次海水养殖浪潮，经济效益显著，有力地推动了我国海水养殖的产业结构调整和可持续发展。然而在海水养殖发展过程中也存在着诸多问题，尤其是早期发育阶段的高死亡率，严重制约了我国海水养殖产业的稳定和健康发展。 海水鱼类养殖的关键为高质量，高存活率苗种的生产和培育，由于鱼类种类繁多，生物多样性丰富，对应实际的繁育技术，尤其是新品种的开发，必须要做出相应的调整。这就要求我们必须对每一种鱼类早期发育有所了解，并将形态和组织上的数据用于指导生产。 本文通过显微观察和组织学研究，主要描述和研究了我国北方三种重要的海水经济鱼类(条斑星鲽、杂交鲆、条石鲷)的早期发育生物学，并结合实际生产进一步阐明关键期的产生原因，机理以及采用相应的对策。具体结果如下： 1.条斑星鲽：作为冷温性鲆鲽鱼类，条斑星鲽早期发育过程的特征主要有： ① 条斑星鲽受精卵无油球，卵子呈半浮性；不同步卵裂现象提前，发生在第三次卵裂；卵裂期裂球大小差异大。孵化过程较长，在水温8 ± 0.3℃，盐度33的条件下，经9 d孵化。条斑星鲽胚胎发育的不同时期对温度的敏感性不同，其中原肠期对温度比较敏感。 ②在8-10℃，盐度33的条件下，8-9 dph开口摄食。且开口时，其吻前端出现有一点状黑褐色素，构成了条斑星鲽仔鱼“开口期”的重要标志。卵黄囊于消失。在后期仔鱼末期，背鳍和臀鳍上形成特有的黑褐色条斑带。 ③杯状细胞首先出现在咽腔后部和食道前段，胃腺和幽门盲囊出现于29 dph，变态期始于30dph。在条斑星鲽早期发育过程中，观察到其直肠粘膜层细胞质出现大量嗜伊红颗粒，为仔鱼肠道上皮吸收的蛋白质。 ④首先淋巴化的免疫器官是头肾，然后是胸腺和脾脏，这与大部分硬骨鱼类不同。条斑星鲽除头肾和脾脏外，胸腺实质也形成MMCs。其中以脾脏形成MMCs最为丰富，形态多样。 2. 杂交鲆：为同属的牙鲆和夏鲆间的远缘杂交种，其发育过程的特点为： ① 在温度为15.4～16.0℃，杂交鲆胚胎从受精到孵化所需的时间为76 h左右，胚孔关闭前期，胚胎先出现视囊及克氏囊，而后形成体节。孵出前胚体在卵膜内环绕不到1周。 ② 孵化后消失。杂交鲆群体变态间隔长(34-60 dph)，且变态高峰期出现的冠状幼鳍不明显(与母本牙鲆相比)，数量为7-8根。 ③组织学观察发现，其消化系统中胃腺出现较晚，且胃腺发育过程缓慢(与母本牙鲆相比)。甲状腺滤泡增生不明显，颜色较浅，数量较少。杂交鲆在早期发育过程中，并没有出现鳔原基。 3. 条石鲷作为岩礁性的暖水性鱼类，早期发育过程也较为特殊，包括外形以及内部的器官结构。主要特点有： ① 受精卵：受精卵卵黄上具有龟裂结构，为鱼卵的分类特征之一。 ② 初孵仔鱼：初孵仔鱼背鳍膜上的黑色素，从体背面向背鳍膜边缘移动，到3dph仔鱼基本消失，此为本种仔鱼发育所特有的特点。 ③ 后期仔鱼和稚鱼：肠道肌肉层加厚明显，仔稚鱼胃肠排空率急剧上升，死亡率增加，通过改善常规的投饵方式部分解决了这个死亡高峰的问题。在幼鱼初期，牙齿融合为骨喙，为石鲷科鱼类的特征。 ④胸腺上皮分泌细胞：类似的现象同样在虹鳟鱼中发现，但是虹鳟鱼胸腺上皮分泌细胞不如条石鲷的丰富，同样也不如条石鲷的排列整齐，而是零星分布在胸腺上皮与咽腔接触的表面。除了正常的造血器官—脾脏和头肾外，肝脏、胰腺和鳔等多种组织等也出现MMCs，此现象在硬骨鱼类不多见，一般发生在软骨鱼类。

Description of a new genus and two new species of Ioninae (Isopoda : Epicaridea : Bopyridae) parasites of Leucosiidae (Decapoda : Brachyura) from Beibu Gulf

A new genus, Onkokepon n. gen., and two new species, O. articulatus n. sp. and O. beibuensis n. sp., infesting Leucosia longibranchia Shen & Chen and Leucosia unidentata de Haan, respectively, are described from Beibu Gulf in China and Vietnam. Neither of these species of Leucosia has previously been reported as bopyrid hosts. The new genus differs from other ionine bopyrid genera in the presence of a well-developed tubercular frontal lamina, a deeply digitate barbula, rudimentary subcircular pleopodal endopodites, and lacking coxal plates. O. articulatus n. sp. is distinguished from O. beibuensis n. sp. by having articulated maxillipedal palp, blunt posterolateral point of oostegite 1 and setose triangular frontal lamina of the female.

Study on steel corrosion in different seabed sediments

A series of simulation experiments on carbon steel (A(3) steel) and low alloy steel (16 Mn steel) in marine atmosphere (MA), seawater (SW) and seabed sediment (SBS) including rough sea sand, fine sea sand and seabed mud were carried out indoors for a year or so by means of individually hanging plates (IHP) and electrically connected hanging plates (ECHP). The corrosion of steels in SBS was mainly due to the macrogalvanic cell effect. The steel plates at the bottom of SBS, as the anode of a macrogalvanic cell, showed the heaviest corrosion with a corrosion rate of up to 0.12 mm/a, approximately equal to that of steel plates in marine atmosphere. The test results showed that the corrosion rates of A(3) and 16 Mn steel in marine environment were in the order: MA > SW > SBS by the IHP method; and MA > SBS > SW by the ECHP method. The corrosion rates of steels in the water/sediment interface were directly proportional to the grain size of the SBS by the ECHP method, but those of steels in the water/sediment interface did not vary with the grain size of SBS by the IHP method. The corrosion rate of low-alloy steel was a little higher than that of carbon steel. The results of this study have important applications for design of offshore steel structures such as oil platform, pier, and port.

机器人研磨抛光工艺研究与实现

机器人研磨抛光工艺研究建立在大量机器人磨抛试验的基础上。本文针对加工对象——有机玻璃,在满足被加工工件质量的前提下,确定了机器人研磨抛光加工时磨片的合理使用顺序、规划加工路径和安排正交试验,以获得机器人磨抛加工的最优工艺参数组合,并制定机器人磨抛的加工策略。最后通过机器人研磨抛光加工实例,进一步验证了机器人的研磨抛光工艺知识有其合理性。

大型激光叠焊系统研究与开发

介绍一种新型激光叠焊系统,利用该系统可将尺寸范围为12.0m×1.5m厚度不等的两块不锈钢板重叠焊接在一起。针对大尺寸不锈钢板尺寸大、易变形等特点提出了主—辅式压紧机构,有效地控制了焊接过程中大尺寸板材的变形并消除了板材间隙;设计了ufxyz型四轴联动方案:u轴与x轴同向,u轴驱动钢板进行大范围运动,x轴驱动激光头小范围运动。u轴与x轴的复合运动提高系统精度的同时提高了系统焊接动态响应速度。对实际焊接板材进行试验验证,结果表明使用该系统进行焊接的钢板可承受压强最大能达到6.1MPa。

青藏高原及邻区面波频散反演--岩石圈-软流层体系结构研究

The Qinghai-Tibet Plateau lies in the place of the continent-continent collision between Indian and Eurasian plates. Because of their interaction the shallow and deep structures are very complicated. The force system forming the tectonic patterns and driving tectonic movements is effected together by the deep part of the lithosphere and the asthenosphere. It is important to study the 3-D velocity structures, the spheres and layers structures, material properties and states of the lithosphere and the asthenosphere for getting knowledge of their formation and evolution, dynamic process, layers coupling and exchange of material and energy. Based on the Rayleigh wave dispersion theory, we study the 3-D velocity structures, the depths of interfaces and thicknesses of different layers, including the crust, the lithosphere and the asthenosphere, the lithosphere-asthenosphere system in the Qinghai-Tibet Plateau and its adjacent areas. The following tasks include: (1)The digital seismic records of 221 seismic events have been collected, whose magnitudes are larger than 5.0 over the Qinghai-Tibet Plateau and its adjacent areas. These records come from 31 digital seismic stations of GSN , CDSN、NCDSN and part of Indian stations. After making instrument response calibration and filtering, group velocities of fundamental mode of Rayleigh waves are measured using the frequency-time analysis (FTAN) to get the observed dispersions. Furthermore, we strike cluster average for those similar ray paths. Finally, 819 dispersion curves (8-150s) are ready for dispersion inversion. (2)From these dispersion curves, pure dispersion data in 2°×2° cells of the areas (18°N-42°N, 70°E-106°E) are calculated by using function expansion method, proposed by Yanovskaya. The average initial model has been constructed by taking account of global AK135 model along with geodetic, geological, geophysical, receiving function and wide-angle reflection data. Then, initial S-wave velocity structures of the crust and upper mantle in the research areas have been obtained by using linear inversion (SVD) method. (3)Taking the results of the linear inversion as the initial model, we simultaneously invert the S wave velocities and thicknesses by using non-linear inversion (improved Simulated Annealing algorithm). Moreover, during the temperature dropping the variable-scale models are used. Comparing with the linear results, the spheres and layers by the non-linear inversion can be recognized better from the velocity value and offset. (4)The Moho discontinuity and top interface of the asthenosphere are recognized from the velocity value and offset of the layers. The thicknesses of the crust, lithosphere and asthenosphere are gained. These thicknesses are helpful to studying the structural differentia between the Qinghai-Tibet Plateau and its adjacent areas and among geologic units of the plateau. The results of the inversion will provide deep geophysical evidences for studying deep dynamical mechanism and exploring metal mineral resource and oil and gas resources. The following conclusions are reached by the distributions of the S wave velocities and thicknesses of the crust, lithosphere and asthenosphere, combining with previous researches. (1)The crust is very thick in the Qinghai-Tibet Plateau, varying from 60 km to 80 km. The lithospheric thickness in the Qinghai-Tibet Plateau is thinner (130-160 km) than its adjacent areas. Its asthenosphere is relatively thicker, varies from 150 km to 230 km, and the thickest area lies in the western Qiangtang. India located in south of Main Boundary thrust has a thinner crust (32-38 km), a thicker lithosphere of about 190 km and a rather thin asthenosphere of only 60 km. Sichuan and Tarim basins have the crust thickness less than 50km. Their lithospheres are thicker than the Qinghai-Tibet Plateau, and their asthenospheres are thinner. (2)The S-wave velocity variation pattern in the lithosphere-asthenosphere system has band-belted distribution along east-westward. These variations correlate with geology structures sketched by sutures and major faults. These sutures include Main Boundary thrust (MBT), Yarlung-Zangbo River suture (YZS), Bangong Lake-Nujiang suture (BNS), Jinshajiang suture (JSJS), Kunlun edge suture (KL). In the velocity maps of the upper and middle crust, these sutures can be sketched. In velocity maps of 250-300 km depth, MBT, BNS and JSJS can be sketched. In maps of the crustal thickness, the lithospheric thickness and the asthenospheric thickness, these sutures can be still sketched. In particular, MBT can be obviously resolved in these velocity maps and thickness maps. (3)Since the collision between India and Eurasian plate, the “loss” of surface material arising from crustal shortening is caused not only by crustal thickening but also by lateral extrusion material. The source of lateral extrusion lies in the Qiangtang block. These materials extrude along the JSJS and BNS with both rotation and dispersion in Daguaiwan. Finally, it extends toward southeast direction. (4)There is the crust-mantle transition zone of no distinct velocity jump in the lithosphere beneath the Qiangtang Terrane. It has thinner lithosphere and developed thicker asthenosphere. It implies that the crust-mantle transition zone of partial melting is connected with the developed asthenosphere. The underplating of asthenosphere may thin the lithosphere. This buoyancy might be the main mechanism and deep dynamics of the uplift of the Qinghai-Tibet hinterland. At the same time, the transport of hot material with low velocity intrudes into the upper mantle and the lower crust along cracks and faults forming the crust-mantle transition zone.