Establishing Submersed Macrophytes via Sinking and Colonization of Shoot Fragments Clipped off Manually

In this paper, sinking and growth of apexes and mid-stems of Myriophyllum spicatum L., Hydrilla verticillata （L.f.） Royle and Ceratophyllum demersum L. in concrete ponds containing eutrophic water and sediment were investigated. Sinking rates of apexes and mid-stems reached 34.8% and 4.4% at the 6 th day and 91.1% and 66.7% at the 22 nd day for M. spicatum, 57.8% and 55.6% at the 6 th day and 100% and 97.8% at the 22 nd day for H. vertieillata, 18.9% and 86.7% at the 6 th day and 95.6% and 100% at the 22 nd day for C. demersum, respectively. Most sunken fragments established themselves successfully with significant growth. Total shoot length ofplantlets developed from apexes and mid-stems increased by 399% and 61% for M. spicatum, 593% and 256% for H. vertieillata and 114% and 104% for C. demersum, respectively. The results showed that it was feasible to establish submersed macrophytes via sinking and colonization of shoot fragments clipped off manually.     

Biosorption and biodegradation of polycyclic aromatic hydrocarbons by Phanerochaete chrysosporium in aqueous solution

Biosorption and biodegradation of phenanthrene and pyrene by live and heat-killed Phanerochaete chrysosporium are investigated to elucidate the bio-dissipation mechanisms of polycyclic aromatic hydrocarbons(PAHs) in aqueous solution and its regulating factors.The effects of nutrient conditions(carbon source and nitrogen source concentrations),the co-existing Cu 2+,and repeated-batch feed of PAHs on the biosorption and biodegradation are systematically studied.The removal of PAHs by dead bodies of P.chrysosporium is attributed to biosorption only,and the respective partition coefficients of phenanthrene and pyrene are 4040 and 17500 L/kg.Both biosorption and biodegradation contribute to the dissipation of PAHs by live P.chrysosporium in water.After a 3-d incubation,the removal percentage via biosorption are 19.71% and 52.21% for phenanthrene and pyrene,respectively.With the increase of the incubation time(3 40 d),biodegradation gradually increases from 20.40% to 60.62% for phenanthrene,and from 15.55% to 49.21% for pyrene.Correspondingly,the stored-PAHs in the fungal bodies decrease.Under the carbon-rich and nitrogen-limit nutrient conditions,the removal efficiency and biodegradation of phenanthrene and pyrene are significantly promoted,i.e.99.55% and 92.77% for phenanthrene,and 99.47% and 83.97% for pyrene after a 60-d incubation.This phenomenon is ascribed to enhanced-biosorption due to the increase of fungal biomass under carbon-rich condition,and to stimulated-biodegradation under nitrogen-limit condition.For the repeated-batch feed of phenanthrene,the pollutant is continuously removed by live P.chrysosporium,and the contribution of biodegradation is enhanced with the repeated cycles.After 3 cycles,the biodegradation percentage is up to 90% with each cycle of a 6-d incubation.     

Root and xylem ABA changes in response to soil drying in two woody plants

Two woody plants, Platycladus orientalise (tolerant to drought) and Acacia auriculi-formis (sensitive to drought), have been subjected to rapid and slow soil drying. ABA levels in their roots and xylem sap have been determined using radioimmunoassay (RIA, sensitivity is 0.4 pmol per assay vial) with a monoclonal antibody against ( + )-ABA. ABA contents of P. orientalise and A. auriculiformis growing in well watered soil are 0.3 and 2.5 nmol·gDW-1 in roots and 1.6 and 0.4 μmol in xylem saps, respectively. A rapid soil drying has been applied to these two plants with soil water content (SWC) being reduced to 0.02 and 0.06 g·gDW-1 respectively. Under such treatment, ABA was increased by 22 times and 2 times in roots and by 7 times and 34 times in xylem saps respectively for P. orientalise and A. auriculiformis. After rewatering for 6 d, ABA in roots and xylem sap of both species returned to control levels. When a slow soil drying was applied, SWC was reduced to 0.1 and 0.13 g·gDW-1 respectively for P. orientalise and A. auriculiformis. ABA was increased by 5 times and 1.6 times in roots and by 6 times and 19 times in xylem saps respectively for these two plants. ABA in roots and xylem saps decreased to near control levels 8 d after watering. Plant leaf water potentials of both plants hardly changed at times when root and xylem ABA showed substantial increase in response to soil drying. It is concluded that ABA levels in the roots and xylem saps of P. orientalise and A. auriculiformis are more sensitively regulated than leaf water potential in response to soil drying and can act as a chemical signal in root-shoot communications of the drought stress.     

Application of Spacer Fabric for Protecting Cushion

Spacer fabric is a typical three-dimensional fabric, including upper layer, lower layer, and spacer layer. It is widely applied in protecting cushion products for unique space structure, which attributes good comfortability to infants and the disabled elderly in reducing diseases resulting from hot and humidity under long-time sitting and lying period. It necessitates studying the microenvironment change between body and clothes and corresponding performance. Compressibility. air permeability, heat and moisture permeability, and bending and humiture in microenvlronment of spacer fabric are analyzed and compared with foam cushion and nonwoven cushion. Experimental results show that corresponding performance of spacer fabric is better in protecting cushion than those of foam and nonwoven. Compared with traditional foam cushion and non-woven cushion, spacer fabric is more suitable for protecting cushion, and provides an alternative and optimal cushion material in medical products to protect infants and the disabled elderly from bedsores resulted from long-time sitting and lying.     

Ultrastructure of spermatozoa of Bullacta exarata （philippi） and its significance on reproductive evolution and physio-ecological adaptation

The morphology and ultrastructure of Bullacta exarata spermatozoa observed by light and transmission electron microscopy are presented in this paper. The spermatozoon is composed of head with a simple acrosomal complex and an elongated nucleus, and tail with a midpiece, principal piece and an end piece. The midpiece consists of a mitochondrial ring, and the principal piece is composed of axoneme and lateral fin. The structure of B. exarata spermatozoa differs significantly from that of other gastropods, especially in the lateral fin and the principal piece, which was described scarcely before. A comparison is made between B. exarata and other gastropods, and its significance on reproductive evolution and physio-ecological adaptation is preliminarily discussed.     

Data Acquisition, Analysis and Applications of Multi-sensor Integration

This paper presents some key techniques for multisensor integration system, which is applied to the intelligent transportation system industry and surveying and mapping industry, e.g. road surface condition detection, digital map making. The techniques are synchronization control of multisensor, spacetime benchmark for sensor data, and multisensor data fusion and mining. Firstly, synchronization control of multisensor is achieved through a synchronization control system which is composed of a time synchronization controller and some synchronization subcontrollers. The time synchronization controller can receive GPS time information from GPS satellites, relative distance information from distance measuring instrument and send spacetime information to the synchronization subcontroller. The latter can work at three types of synchronization mode, i.e. active synchronization, passive synchronization and time service synchronization. Secondly, spacetime benchmark can be established based on GPS time and global reference coordinate system, and can be obtained through position and azimuth determining system and synchronization control system. Thirdly, there are many types of data fusion and mining, e.g. GPS/Gyro/DMI data fusion, data fusion between stereophotogrammetry and PADS, data fusion between laser scanner and PADS, and data fusion between CCD camera and laser scanner. Finally, all these solutions presented in paper have been applied to two areas, i.e. landborne intelligent road detection and measurement system and 3D measurement system based on unmanned helicopter. The former has equipped some highway engineering Co., Ltd. and has been successfully put into use. The latter is an ongoing research.     

粉末冶金制备的AISI 8620钢渗碳后的磨损和力学性能

The effect of carburization on the tensile strength and wear resistance of AISI 8620 steel produced via powder metallurgy was investigated. Alloys 1 and 2 (with 0.2wt% C and 0.25wt% C, respectively) were first pressed at 700 MPa and then sintered at 1300, 1400, or 1500°C for 1 h. The ideal sintering temperature of 1400°C was determined. Afterward, Alloys 1 and 2 sintered at 1400°C were carburized at 925°C for 4 h. The microstructure characterization of alloys was performed via optical microscopy and scanning electron microscopy. The mechanical and wear behavior of carburized and noncarburized alloys were investigated via hardness, tensile, and wear tests. After carburization, the ultimate tensile strength of Alloys 1 and 2 increased to 134.4% and 138.1%, respectively. However, the elongation rate of Alloys 1 and 2 decreased to 62.6% and 64.7%, respectively. The wear depth values of Alloy 2 under noncarburized and carburized conditions and a load of 30 N were 231.2 and 100.1 μm, respectively. Oxidative wear changed to abrasive wear when the load transitioned from 15 to 30 N.     

Politeness Strategies in English and Chinese Business Letters

This paper explores similarities and differences in the application of positive and negative politeness strategies to English and Chinese business letters and illuminates underlying causes of such similarities and differences.The results indicate that English and Chinese business letters have some common features and great discrepancies in categories and the distribution of positive and negative politeness strategies.It is argued that common situational factors,different cultural backgrounds and different syntactic features result in their similarities and differences.     

低温在医学上的应用

介绍了低温在医学上的应用，它包括冷冻外科、低温保存、低度体温、低温干燥4个方面，冷冻医疗主要用液氮作低温制剂，它价廉、简便、易行。已广泛应用于临床各科治疗良性及恶性肿瘤，疗效确切，另在低温保存血液、精液、组织、器官方面成绩可，有待于进一步研究发展。     

Assessment of alternated cooling and heating treatment by US combined CEUS in the VX2 rabbit liver tumor model

Inoperable liver tumors are often treated by thermal ablation that destroys the tumor in situ and spares the adjacent hepatic tissue.Thermal–physical treatment has many advantages,but treatment by freezing or heating alone has some limitations.By taking the advantages and disadvantages of cryosurgery and thermotherapy into consideration,a new thermal technique that combines cryosurgery and radio frequency ablation has been proposed,thereby overcoming the disadvantages of each treatment strategy and improving therapeutic outcomes.This new approach remains to be systematically studied in the liver;therefore,this study was performed to estimate survival after alternated cooling and heating ablation therapy in a VX2 rabbit liver tumor model.Sixteen days after VX2 carcinoma implantation into the rabbit liver,tumors were treated with alternated cooling and heating ablation therapy.Rabbits were monitored for 6 months after treatment and assessed with ultrasound(US)and computed tomography at 1,7,14,and 30 days posttreatment.Untreated tumor-bearing animals served as the control group.Our results show that alternate freezing and heating ablation therapy resulted in a good recovery of VX2 rabbits.Compared with the control group,treated rabbits lived significantly longer(P\0.05),with 70%of treated animals surviving to 196 days posttreatment without metastasis or recurrence,while none of the controls did so.There was no local recurrence in the treatment group.All rabbits in the control group developed metastasis,while metastasis was only observed in 30% of treated rabbits.These results suggest that alternate cooling and heating ablation therapy can prolong the survival time of rabbits with VX2 liver tumors and is an effective method for tumor therapy.Furthermore,we also showed in this model that contrast enhanced US is a valid follow-up approach to assess treatment effectiveness.     

在生物样品冷冻中具有移动边界的传热研究

当冷却介质的降温速率为常数时,本文用摄动法求解了相交界面随时间的移动及生物组织内的温度场;讨论了各种因素对此的影响。其结果显示,这些解在第三类边界条件和在第一类边界条件下具有较大的差异。     

低温抗冻剂溶液玻璃化转变的临界冷却速率

生物材料的玻璃化低温保存技术已受到广泛注意。本文修正了Foutron的半经验结晶动力学模型,并用由此得到的解析表达式,构造各种浓度溶液在等温转变时的温度-时间-转变(TTT)曲线和变温转变时的连续-冷却-转变(CCT)曲线,预测实现玻璃化转变所需的最小冷却速率,以反映溶液玻璃化形成倾向的大小。结果表明,丙二醇的玻璃化形成倾向大于乙二醇和甘油。若在丙二醇溶液中加入丁二醇,可进一步提高其玻璃化形成能力。     

纳米冷冻治疗学——纳米医学的新前沿

近年来,借助低温方法对恶性肿瘤实施靶向治疗已成为肿瘤临床和生物医学工程研究领域中的重要主题。为了突破制约传统冷冻手术治疗效率的技术瓶颈,本实验室首次提出将纳米技术与低温工程学相结合,以发展先进肿瘤微创治疗方法的技术理念,并在相应的机理分析、试验研究和医疗仪器的研制等方面取得进展。种种态势表明,纳米冷冻治疗学正成为纳米医学领域内极具探索价值的新前沿。由于这一方法在调控冰球生长方向和强度、确保肿瘤适形治疗以及提高医学成像分辨率等方面均优于传统手段,因而在预期的临床应用上可望取得较佳结果。该方法的提出,为发展高效物理靶向治疗开辟了一条新的途径。本文在简要剖析低温医学技术发展态势的基础上,评述了纳米冷冻治疗这一未来纳米医学领域可能具有重要意义的概念,阐述了其基本特点、功能和应用方式等问题,并以本实验室前期取得的系列进展为例,剖析了在现阶段发展纳米冷冻治疗技术的途径;同时也对纳米冷冻治疗学的前景进行了展望,归纳出了一些有待解决的基础科学和应用技术问题。     

Ice-free cryopreservation of mouse embryos at -196 degrees C by vitrification

The failure of complex mammalian organs, such as the kidney, to function following freezing to low temperatures is thought to be due largely to mechanical disruption of the intercellular architecture by the formation of extracellular ice. Classical approaches to the avoidance of ice formation through the imposition of ultra-rapid cooling and warming rates or by gradual depression of the equilibrium freezing point during cooling to -80 degrees C have not been adequate. An alternative approach relies on the ability of highly concentrated aqueous solutions of cryoprotective agents to supercool to very low temperatures. At sufficiently low temperatures, these solutions become so viscous that they solidify without the formation of ice, a process termed vitrification. When embryo suspensions are cryopreserved using conventional procedures, this supercooling behaviour allows intracellular vitrification, even in the presence of extracellular ice. We have therefore used mouse embryos to examine the feasibility of obtaining high survival following vitrification of both the intra- and extracellular solutions and report here that in properly controlled conditions embryos seem to survive in high proportions after cryopreservation in the absence of ice.     

井筒冻结法施工的常见问题及防治措施

在不稳定表土层中施工井筒时，冻结法具有大量的优点，主要包括：适应性强；支护结构灵活、易控制；膈水性好；对环境影响小等。Ⅲ因此，冻结法在井筒的特殊施工中被大量应用。我国煤矿于1955年在开滦林西风井首次使用冻结法凿井，此后，冻结法凿井技术逐渐推广。现在，我国已是世界上用冻结法凿井穿过表土层最厚的国家之一。但是井筒在冻结法施工中，仍然存在很多的问题，这些问题必须引起我们的高度重视。本文主要介绍了冻结法施工的原理及其存在的主要问题，并提出了相关的防治措施。     

生物组织冻结相变过程的数值模拟

建立了生物组织(含正常生物组织和肿瘤)冻结过程的传热模型.生物组织作为一种多孔介质,其相变发生在一个温度范围内,且存在一个固相与液相共存的糊状过渡区.采用显热容法模拟了生物组织冻结过程中的传热和冰晶增长过程.模拟结果显示,在冻结过程中,冷刀的初始温度越低,冷刀的降温速率越快,生物组织内温度下降和冰晶增长的速率越快.结果还表明组织中液相流动会增加生物组织内传热和冰晶生长的速度.计算结果为冷刀设计和冷冻外科手术提供了理论依据.     

提升冷冻手术中冰球监测对比度的超声弹性成像方法

生物组织发生冻结前后,其弹性会呈数量级改变.通过剖析超声弹性成像与低温手术的特点,提出将超声弹性成像用于冷冻手术中冰球形成与消融过程的监测,以显著提升常规超声监测方法的成像质量.为初步认识这一方法,借助Comsol和Matlab软件仿真出冷冻手术相应数据,在此基础上应用超声弹性成像算法对之加以计算评估,从理论上论证了超声弹性成像法在实现高对比度冰球监测方面的可行性和重要价值,为今后试验研究及硬件系统的发展打下了基础.新方法作为一种具有高清晰度、低成本的冰球影像监测技术,可望在低温外科手术中发挥重要作用.     

显像管玻壳成形过程中温度场的数值模拟

研究了显像管玻壳成形过程中温度场集成冷却模拟方法,开发了工艺参数和模具冷却结构优化系统.该系统利用有限差分法,在厚度方向上对玻壳采用局部的一维瞬态分析,运用三维边界元方法模拟模具的三维热传导,玻壳和模具通过耦合分析来匹配型腔表面的温度和热流量.研究表明,所提出的集成和耦合数值模型模拟结果与实验结果吻合良好.