bluuebunny/crossref_metadata_2025 huggingface dataset:
Differentiation of Stem Cells: Strategies for Modifying Surface Biomaterials
Authors: Fu Ru-Huei , Wang Yu-Chi , Liu Shih-Ping , Huang Chin-Mao , Kang Yun-Han , Tsai Chang-Hai , Shyu Woei-Cherng , Lin Shinn-Zong
Published: December 2010

Stem cells are a natural choice for cellular therapy because of their potential to differentiate into a variety of lineages, their capacity for self-renewal in the repair of damaged organs and tissues in vivo, and their ability to generate tissue constructs in vitro. Determining how to efficiently drive stem cell differentiation to a lineage of choice is critical for the success of cellular therapeutics. Many factors are involved in this process, the extracellular microenvironment playing a significant role in controlling cellular behavior. In recent years, researchers have focused on identifying a variety of biomaterials to provide a microenvironment that is conducive to stem cell growth and differentiation and that ultimately mimics the in vivo situation. Appropriate biomaterials support the cellular attachment, proliferation, and lineage-specific differentiation of stem cells. Tissue engineering approaches have been used to incorporate growth factors and morphogenetic factors—-factors known to induce lineage commitment of stem cells—into cultures with scaffolding materials, including synthetic and naturally derived biomaterials. This review focuses on various strategies that have been used in stem cell expansion and examines modifications of natural and synthetic materials, as well as various culture conditions, for the maintenance and lineage-specific differentiation of embryonic and adult stem cells.
Initial Observations of Cell-Mediated Drug Delivery to the Deep Lung
Authors: Kumar Arun , Glaum Mark , El-Badri Nagwa , Mohapatra Shyam , Haller Edward , Park Seungjoo , Patrick Leslie , Nattkemper Leigh , Vo Dawn , Cameron Don F.
Published: December 2010

Using current methodologies, drug delivery to small airways, terminal bronchioles, and alveoli (deep lung) is inefficient, especially to the lower lungs. Urgent lung pathologies such as acute respiratory distress syndrome (ARDS) and post-lung transplantation complications are difficult to treat, in part due to the methodological limitations in targeting the deep lung with high efficiency drug distribution to the site of pathology. To overcome drug delivery limitations inhibiting the optimization of deep lung therapy, isolated rat Sertoli cells preloaded with chitosan nanoparticles were use to obtain a high-density distribution and concentration (92%) of the nanoparticles in the lungs of mice by way of the peripheral venous vasculature rather than the more commonly used pulmonary route. Additionally, Sertoli cells were preloaded with chitosan nanoparticles coupled with the anti-inflammatory compound curcumin and then injected intravenously into control or experimental mice with deep lung inflammation. By 24 h postinjection, most of the curcumin load (~90%) delivered in the injected Sertoli cells was present and distributed throughout the lungs, including the perialveloar sac area in the lower lungs. This was based on the high-density, positive quantification of both nanoparticles and curcumin in the lungs. There was a marked positive therapeutic effect achieved 24 h following curcumin treatment delivered by this Sertoli cell nanoparticle protocol (SNAP). Results identify a novel and efficient protocol for targeted delivery of drugs to the deep lung mediated by extratesticular Sertoli cells. Utilization of SNAP delivery may optimize drug therapy for conditions such as ARDS, status asthmaticus, pulmonary hypertension, lung cancer, and complications following lung transplantation where the use of high concentrations of anti-inflammatory drugs is desirable, but often limited by risks of systemic drug toxicity.
Augmenting Therapy of Ovarian Cancer Efficacy by Secreting IL-21 Human Umbilical Cord Blood Stem Cells in Nude Mice
Authors: Hu Weihua , Wang Jing , Dou Jun , He Xiangfeng , Zhao Fengshu , Jiang Cuilian , Yu Fangliu , Hu Kai , Chu Lili , Li Xiaoli , Gu Ning
Published: December 2010

In the present study, CD34+ human umbilical cord blood stem cells (UCBSCs) were engineered to express interleukin-21 (IL-21) and then were transplanted into A2780 ovarian cancer xenograft-bearing Balb/c nude mice. The therapeutic efficacy of this procedure on ovarian cancer was evaluated. The findings from the study indicated that UCBSCs did not form gross or histological teratomas until up to 70 days postinjection. The CD34+ UCBSC-IL-21 therapy showed a consistent effect in the ovarian cancer of the treated mice, delaying the tumor appearance, reducing the tumor sizes, and extending life expectancy. The efficacy was attributable to keeping CD34+ UCBSC-IL-21 in the neoplastic tissues for more than 21 days. The secreted IL-21 not only increased the quantity of CD11a+ and CD56+ NK cells but also increased NK cell cytotoxicities to YAC-1 cells and A2780 cells, respectively. The efficacy was also associated with enhancing the levels of IFN-γ, IL-4, and TNF-α in the mice as well as the high expressions of the NKG2D and MIC A/B molecules in the tumor tissues. This study suggested that transferring CD34+ UCBSC-IL-21 into the nude mice was safe and feasible in ovarian cancer therapy, and that the method would be a promising new strategy for clinical treatment of ovarian cancer.
Comparative Study of Methods for Administering Neural Stem/Progenitor Cells to Treat Spinal Cord Injury in Mice
Authors: Takahashi Yuichiro , Tsuji Osahiko , Kumagai Gentaro , Hara Chikako Miyauchi , Okano Hirotaka James , Miyawaki Atsushi , Toyama Yoshiaki , Okano Hideyuki , Nakamura Masaya
Published: December 2010

To investigate potential cures for spinal cord injury (SCI), several researchers have transplanted neural stem/progenitor cells (NS/PCs) into the injured spinal cord by different procedures, including intralesional (IL), intrathecal (IT), and intravenous (IV) injection. However, there are no reports quantifying or comparing the number of cells successfully transplanted to the lesion site by each procedure in vivo. The purpose of the present study was to determine the optimal method of cell transplantation to the SCI site in terms of grafted cell survival and safety. For this purpose, we developed mouse NS/PCs that expressed a novel Venus-luciferase fusion protein that enabled us to detect a minimum of 1,000 grafted cells in vivo by bioluminescence imaging (BLI). After inducing contusive SCI at the T10 level in mice, NS/PCs were transplanted into the injured animals three different ways: by IL, IT, or IV injection. Six weeks after the transplantation, BLI analysis showed that in the IL group, the luminescence intensity of the grafted cells had decreased to about 10% of its initial level, and appeared at the site of injury. In the IT group, the luminescence of the grafted cells, which was distributed throughout the entire subarachnoid space immediately after transplantation, was detected at the injured site 1 week later, and by 6 weeks had gradually decreased to about 0.3% of its initial level. In the IV group, no grafted cells were detected at the site of injury, but all of these mice showed luminescence in the bilateral chest, suggesting pulmonary embolism. In addition, one third of these mice died immediately after the IV injection. In terms of grafted cell survival and safety, we conclude that the IL application of NS/PCs is the most effective and feasible method for transplanting NS/PCs into the SCI site.
Novel Cell Culture Model Using Pure Hydrostatic Pressure and a Semipermeable Membrane Pouch
Authors: Mizuno Shuichi
Published: December 2010

Cell constructs and culture methods are essential tools in tissue engineering. The cell construct should be equivalent to the native cartilage it is intended to replace. Thus, three-dimensional cell constructs are usually composed of a high density of cells and dense extracellular matrix. However, dense constructs suffer from a lack of passive nutrient supply, gas exchange, and removal of degraded debris. We have developed a novel hydrostatic pressure/perfusion culture system that improves the quality of neo-tissues, providing an automated and affordable system for clinical applications. We have also developed a semipermeable membrane pouch that contains a fragile amorphous cell carrier. Although amorphous material is difficult to handle, it is a useful medium in which to deliver cells to the desired site via injection. We evaluated phenotypes of bovine articular chondrocytes embedded in a collagen type I gel enclosed within membrane pouches permeable to molecules of various sizes. Constant or cyclic hydrostatic pressure was externally applied to the medium phase with a new culture system. Accumulation of cartilage specific matrix was promoted with a 500-kDa cutoff membrane pouch and cyclic hydrostatic pressure at 0.5 MPa, 0.5 Hz. This new method will be useful in the delivery of engineered cells to a desired tissue in regenerative medicine.
Stem Cell Research in Cell Transplantation: Sources, Geopolitical Influence, and Transplantation
Authors: Eve David J. , Fillmore Randolph W. , Borlongan Cesar V. , Sanberg Paul R.
Published: December 2010

If the rapidly progressing field of stem cell research reaches its full potential, successful treatments and enhanced understanding of many diseases are the likely results. However, the full potential of stem cell science will only be reached if all possible avenues can be explored and on a worldwide scale. Until 2009, the US had a highly restrictive policy on obtaining cells from human embryos and fetal tissue, a policy that pushed research toward the use of adult-derived cells. Currently, US policy is still in flux, and retrospective analysis does show the US lagging behind the rest of the world in the proportional increase in embryonic/fetal stem cell research. The majority of US studies being on either a limited number of cell lines, or on cells derived elsewhere (or funded by other sources than Federal) rather than on freshly isolated embryonic or fetal material. Neural, mesenchymal, and the mixed stem cell mononuclear fraction are the most commonly investigated types, which can generally be classified as adult-derived stem cells, although roughly half of the neural stem cells are fetal derived. Other types, such as embryonic and fat-derived stem cells, are increasing in their prominence, suggesting that new types of stem cells are still being pursued. Sixty percent of the reported stem cell studies involved transplantation, of which over three quarters were allogeneic transplants. A high proportion of the cardiovascular systems articles were on allogeneic transplants in a number of different species, including several autologous studies. A number of pharmaceutical grade stem cell products have also recently been tested and reported on. Stem cell research shows considerable promise for the treatment of a number of disorders, some of which have entered clinical trials; over the next few years it will be interesting to see how these treatments progress in the clinic.
Human Amnion Epithelial Cells Prevent Bleomycin-Induced Lung Injury and Preserve Lung Function
Authors: Murphy Sean , Lim Rebecca , Dickinson Hayley , Acharya Rutu , Rosli Sharina , Jenkin Graham , Wallace Euan
Published: December 2010

Human amnion epithelial cells (hAECs) have attracted recent attention as a promising source of cells for regenerative therapies, with reports that cells derived from human term amnion possess multipotent differentiation ability, low immunogenicity, and anti-inflammatory properties. Specifically, in animal models of lung disease characterized by significant loss of lung tissue secondary to chronic inflammation and fibrosis, the transplantation of hAECs has been shown to reduce both inflammation and subsequent fibrosis. To further explore the mechanisms by which hAECs reduce pulmonary fibrosis and enhance lung regeneration, we utilized a bleomycin-induced model of pulmonary fibrosis and investigated the ability of hAECs to reduce fibrosis and thereby improve pulmonary function. We aimed to determine if hAECs, injected into the peritoneal cavity could migrate to the lung, engraft, and form functional lung epithelium, and whether hAECs could modulate the inflammatory environment in the bleomycin-injured lung. We demonstrated that, compared to bleomycin alone, IP administration of hAECs 24 h after bleomcyin, decreased gene expression of the proinflammatory cytokines TNF-α, TGF-β, IFN-γ, and IL-6 and decreased subsequent pulmonary fibrosis with less pulmonary collagen deposition, reduced levels of α-smooth muscle actin and decreased inflammatory cell infiltrate. We also showed that hAECs are able to prevent a decline in pulmonary function associated with bleomycin-induced lung damage. We were unable to detect any significant engraftment of hAECs in injured, or uninjured, lung after administration. The findings from this study support the further investigation of hAECs as a potential cell therapy for inflammatory and fibrogenic diseases.
Schwann Cell Coculture Improves the Therapeutic Effect of Bone Marrow Stromal Cells on Recovery in Spinal Cord-Injured Mice
Authors: Xu Xiaoyun , Geremia Nicole , Bao Feng , Pniak Anna , Rossoni Melissa , Brown Arthur
Published: December 2010

Studies of bone marrow stromal cells (MSCs) transplanted into the spinal cord-injured rat give mixed results: some groups report improved locomotor recovery while others only demonstrate improved histological appearance of the lesion. These studies show no clear correlation between neurological improvements and MSC survival. We examined whether MSC survival in the injured spinal cord could be enhanced by closely matching donor and recipient mice for genetic background and marker gene expression and whether exposure of MSCs to a neural environment (Schwann cells) prior to transplantation would improve their survival or therapeutic effects. Mice underwent a clip compression spinal cord injury at the fourth thoracic level and cell transplantation 7 days later. Despite genetic matching of donors and recipients, MSC survival in the injured spinal cord was very poor (~1%). However, we noted improved locomotor recovery accompanied by improved histopathological appearance of the lesion in mice receiving MSC grafts. These mice had more white and gray matter sparing, laminin expression, Schwann cell infiltration, and preservation of neurofilament and 5-HT-positive fibers at and below the lesion. There was also decreased collagen and chondroitin sulphate proteoglycan deposition in the scar and macrophage activation in mice that received the MSC grafts. The Schwann cell cocultured MSCs had greater effects than untreated MSCs on all these indices of recovery. Analyses of chemokine and cytokine expression revealed that MSC/Schwann cell cocultures produced far less MCP-1 and IL-6 than MSCs or Schwann cells cultured alone. Thus, transplanted MSCs may improve recovery in spinal cord-injured mice through immunosuppressive effects that can be enhanced by a Schwann cell coculturing step. These results indicate that the temporary presence of MSCs in the injured cord is sufficient to alter the cascade of pathological events that normally occurs after spinal cord injury, generating a microenvironment that favors improved recovery.
The Presence of Apoptotic Bone Marrow Cells Impairs the Efficacy of Cardiac Cell Therapy
Authors: Mouquet Frederic , Lemesle Gilles , Delhaye Cedric , Charbonnel Clement , Ung Alexandre , Corseaux Delphine , Fabre Olivier , Juthier Francis , Marchetti Philippe , Neviere Remi , Van Belle Eric , Jude Brigitte , Susen Sophie
Published: December 2010

Injection of autologous bone marrow cells into infarcted myocardium has been proposed to limit the deterioration of cardiac function following myocardial infarction (MI); unfortunately, the beneficial effects observed have been modest. One of the limiting factors is believed to be poor local survival of the injected cells, but the potential impact of apoptosis among the injected cells has yet to be assessed. Therefore, this study aimed to quantify the apoptosis rate in bone marrow mononuclear cells (BMMCs) prepared for cardiac therapy, and to analyze their effects in vitro on cardiomyoblast apoptosis and in vivo on cardiac function recovery following MI. Using rabbit BMMCs prepared by Ficoll gradient, apoptotic cells were detected via Annexin V (AnV) staining. The effects of depleting the apoptotic cell population by means of AnV magnetic beads was tested in vitro after coculture with cardiomyoblasts (H9c2 cells) and in vivo after cell injection into the infarcted area. Left ventricular ejection fraction and scar extent were assessed by echography and histology 2 months later. After Ficoll gradient isolation, 37.3% (33.4–37.9%) of BMMCs were found to be apoptotic (ApoBaseBMMCs). AnV depletion decreased the proportion of apoptotic cells to 20% (17.6–32%) (ApoLowBMMCs). Rabbits treated in vivo with ApoLowBMMCs after MI presented with significantly improved left ventricular ejection fraction [41.4% (41.0–43.6%) vs. 34.6% (34.6–35.9%), p = 0.03), reduced scar extent [20.4% (17.9–24.3%) vs. 25.6% (17.9–27.9%), p = 0.057], and reduced rate of cardiomyocyte apoptosis compared to those treated with ApoBaseBMMCs. H9c2 apoptosis was found to be higher after coculture with ApoBasethan with ApoLowBMMCs [25.6% (22.6–29.6%) vs. 10.1% (6.6–12.6%), p = 0.03], a result partially reproduced by cocultures with microparticle-rich supernatants from BMMCs. The presence of apoptotic cells among BMMCs impairs the efficacy of cardiac cell therapy after MI, an effect possibly mediated by apoptotic microparticles.
Migration et accouchement
Authors: Dejours Roxane
Published: December 2010

Résumé La prise en charge obstétricale des patientes migrantes comporte certaines particularités, qui mettent parfois les équipes soignantes en difficulté. En effet, la confrontation aux différences culturelles n’est pas toujours simple, dans la mesure où, souvent, c’est notre pratique même qui est alors remise en question. Le sentiment d’impuissance et la déception que nous ressentons lorsque nos savoir-faire sont mis en échec sont parfois difficilement surmontables, et de l’incompréhension mutuelle peut surgir, entre patientes et soignants, la colère et l’agressivité. Dans cet article, nous proposons une description et une tentative d’analyse de quelques-unes de ces situations cliniques.
Parentalité en danger : la situation des mères gravement traumatisées
Authors: Gioan Estelle , Mestre Claire
Published: December 2010

Résumé Nous proposons de réfléchir sur la question d’une possible transmission traumatique de la mère à l’enfant qui n’a pas vécu directement les événements traumatogènes, à partir d’une situation clinique. Outre le soin, le suivi permet une prévention auprès de l’enfant. L’abord complémentariste a permis de tenir compte des éléments psychiques et culturels de l’histoire de la mère pour tenter de construire un sens et comprendre la place de l’enfant dans l’économie psychique de la mère. Nous proposons d’aborder cette question par le biais de la théorie de l’attachement ; nous faisons ainsi l’hypothèse que le matériel infantile pathologique exacerbé par le traumatisme psychique fait le lit d’expressions effrayées maternelles et est le canal potentiel d’une transmission traumatique de la mère à l’enfant. Nous mettrons en évidence le travail clinique dans un cadre de cothérapie ethno-psychanalytique, mais également l’intérêt d’un travail en réseau.
À la recherche de l'entrepreneur. Au-delà du modèle du choix rationnel : une figure de l'agir projectif
Authors: Bréchet Jean-Pierre , Prouteau Lionel
Published: December 2010

Résumé La pensée économique entretient une relation compliquée avec la figure de l’entrepreneur. Plusieurs auteurs y ont consacré des travaux importants, mais la théorie néoclassique standard l’a ignorée. Une telle situation montre que le phénomène entrepreneurial comme objet d’étude nécessite le dépassement du réductionnisme économique. L’action collective, son émergence et sa construction, ne peuvent être pensées sans introduire un agir projectif, à la fois créatif et d’anticipation.
Research on the Mechanism of Discharge of Transmission Line in Wind-Sand-Electric Field
Authors: Gao Qiang , Shi Yao Hu
Published: December 2010

In this paper, coupling field model of wind-sand-electricity around transmission line is built to solve mechanism of discharge of transmission line in sandstorm. The model is used to simulated distribution of electric field of transmission line in the condition of strong sand storm happened in Atushi City at March 12, 2006. In the sand-wind-electric field of the transmission line, the peak of electric field strength exceeds the discharge inception. It is considered that corona phenomenon occurs in the sandstorm, which is shown that the proposed method is of efficiency and practicality.
Automatic Two Axes Sun-Tracking System Applied to Photovoltaic System for LED Street Light
Authors: Wang Quan , Zhang Jin , Hu Ran , Shao Ying
Published: December 2010

This paper presents an electromechanical, two axes sun tracking system based on single chip microcomputer (MCU). According to the path of the sun in the space, the earth coordinate system is chosen to design the tracking device. The whole device consists of one worm-drive and one gear-drive, which is operated by two step motors. The photodiodes are used as photoelectric sensors to detect the pointing of the sun. Eight photodiodes are installed in the diameter hole of the hemispherical surface. The comparative signals produced by the diodes array are performed to judge the orientation of the solar panel. The circuit of the control system based on MCU is demonstrated. The comparative signals may be amplified, A/D converted. After a series of signal processing, the signals are sent to the MCU which will produce the pulse to control the speed and steering of step motors. The sun tracking system is an efficient system for solar energy collection. It has been proved that the sun tracking systems can collect up to 50% more energy than what a fixed panel system collects.
Realization and Reliability Analysis of Simulated SCIs in the Yacht Monitoring System
Authors: Tan Xiao Dong , Zhao Yong Sheng , Li Xia , Li Bao Liang , Yao Shi Xuan
Published: December 2010

In this paper, a design method of software simulated SCIs has been proposed to resolve the problem that the built-in SCIs of the MCU could not meet the need of data communications in the research and development of the yacht monitoring system. Two simulated SCIs have been established through building hardware circuits and writing software programs by using the parallel I/O ports and the enhanced capture timer of the MCU. Meanwhile, the error control programs have been designed, and the reliability of the simulated SCIs has been analysed through on-site tests, in order to improve the stability of data transmissions.
Optimum Design of Rotary Non-Contact Electric Power Transmission Device for Ultrasonic Vibration Internal Grinding System
Authors: Yin Zhen , Li Hua , Li Yan , Xie Ou , Li Zheng
Published: December 2010

Through theoretical analysis and simulation, a practical structural and design method of rotary non-contact electric power transmission (RNEPT) device for ultrasonic vibration internal grinding (UVG) system were proposed, experiments about the prototype of the RNEPT device for UVG system were studied, the feasibility of the optimum design methods was verified.
MCU-Based Driven Design for the Electromagnetic Valve of the Repeated Impact Testing Machine
Authors: Liu Xiao Dong , He Jie Guo , Fu Ge Yan , Li Chun Sheng
Published: December 2010

In view of repeated impact condition, developed a repeated impact test machine. This study focuses on using MCU (Micro Controller Unit) to control output of electromagnetic valve what is the core of the machine. The square wave signal , what is issued by AT89s52 and whose cycle and duty cycle can be adjusted, is used to control relay, thereby to control electromagnetic valve of the machine, and ultimately to realize multi-frequency repeated impact under the control of MCU system. A MCU control circuit system is designed at the aim of relay response, including control circuit of hardware, process design of software and anti-jamming design.
Study on Substrate Humidity, EC and Salinity In Situ Detection Technology
Authors: Sheng Qing Yuan , Li Ping Ping , Zhang Xi Liang , Liu Zhi Gang , Zhao Li Juan , Hu Yong Guang
Published: December 2010

Considering the greater character differences between matrix and soil, and the great disparity in physicochemical properties of various substrate, now there is no special equipment to test matrix moisture, electrical conductivity (EC) and salinity of medium .On the basis of analyzing physicochemical properties of various substrate, the relationship between output voltage and water content is studied through piezoelectric type soil moisture probe trial. With "voltage-current" four-terminal method, multi-parameter integrated sensor testing medium moisture and electrical conductivities developed, and through the solution calibration EC measuring model is established. Then relationships among matrix water content, electrical conductivity and salinity are analyzed, and salinity testing model is established. A portable low-cost in-situ multi-parameter detection apparatus, testing substrate humidity, EC and salinities, developed by adopting MCU SPCE06A. Experimental results indicate that detection accuracy of the equipment can meet the need of soilless culture production, and it has greater application and dissemination value.
Research on the Key Process Parameters in Direct Laser Deposition Using Coaxial Inside-Beam Wire Feeding
Authors: Wang Yong Kang , Shi Shi Hong , Fu Ge Yan , Li Chun Sheng
Published: December 2010

Aimed at the disadvantages of the lateral wire feeding in direct laser deposition (DLD), a novel device with coaxial inside-beam wire feeding is applied in the process based on the patent technology of “hollow laser beam and internal wire feeding’’. During the laser cladding process, laser beam can be coupled with wire accurately. The comparison experiments of laser cladding are carried out on the substrate of 45# steel with different process parameters. The effects of crucial process parameters, such as laser power, scanning speed and wire delivery rate on the cladding layer are dicussed. The optimum laser cladding process and related parameters are obtained. Microstructure of the cladding layer is characterized by scanning electron microscopy (SEM). Experimental results show that, wire melts adequately; the cladding layer is symmetrical and smooth; the microstructure is uniformly distributed with no porosity; firm combination with substrate is achieved.
Design of Mechanical and Combustion System for Small Non-Road Diesel Engine to Meet the EPA IV Emission Regulations
Authors: Yin Bi Feng , Guan Tao , He Jiang Guang , Xu Yi
Published: December 2010

Based on 1.9L small non-road diesel engine, mechanical and combustion system were redesigned and optimized to improve the emission performance. The engine block structure such as ribs, bolt hole depth and water jacket were optimized to improve the strength and stiffness and reduce the block’s distortion. The type of piston ring, piston skirt profile and their fit clearances were also optimized, and plat-honing cylinder liner was used to reduce the oil consumption. In combustion system, fuel injection pump, injection nozzle, fuel spray distribution and fuel supply advance angle were modified, combustion chamber was changed to small platform dumbbell-shaped chamber, and the closed-loop exhaust gas recirculation (EGR) system controlled by negative pressure was applied to trade-off the emissions of NOX and PM. The test results show that the emission performance of optimum diesel engine could meet EPA IV emission regulations.
Research Advance in Laser Shock Processing Surface Modification Technology on Metal Alloys
Authors: Li Xing Cheng , Zhang Yong Kang , Chen Ju Fang
Published: December 2010

Laser shock processing is an innovative surface treatment technique to strengthen metals. This process induces a compressive residual stress field which increases fatigue crack initiation life and stress corrosion cracking (SCC) resistance and reduces fatigue crack growth rate. The current status of research and development on laser shock processing of metals, using Q-switched high power lasers is reviewed. Then several key issues are addressed, including the development of the laser peening equipment and the opaque overlay selection and so on. Results to date indicate that laser peening has great potential as a means of improving the mechanical performance of components.
Monocular Vision Based Mobile Robot 3D Map Building
Authors: Li Mao Hai , Sun Li Ning
Published: December 2010

A robust dense 3D feature map is built only with monocular vision and odometry. Monocular vision mounted on the robot front-end tracks the 3D natural landmarks, which are structured with matching Scale Invariant Feature Transform (SIFT) feature matching pairs. SIFT features are highly distinctive and invariant to image scaling, rotation, and change in 3D viewpoints. A fast SIFT feature matching algorithm is implemented with the KD-Tree based nearest search approach in the time cost of O(log2N), and matches with large error are eliminated by epipolar line restriction. A map building algorithm based on 3D spatial SIFT landmarks is designed and implemented. Experiment results on Pioneer mobile robot in a real indoor environment show the superior performance of our proposed method.
Automatic Placing and Removing Manipulator of the Workpiece on Stretcher Based on Electric-Pneumatic Control and PLC Control
Authors: Sheng Xiao Ming , Liu Lei , Xu Yun Qing
Published: December 2010

Workpiece placing and removing for stretcher operated by hand have low precision, low efficiency and poor security. The workpiece automatic placing and removing manipulator of stretcher driven by pneumatic is introduced in this paper，in which two control methods: electric-pneumantic control and PLC program control are advanced to realize stepless speed regulation, overload protection and to complete complex actions easily. The design shows the advantages such as simple structure, low cost, easy to operate and maintenance, high efficiency and reliability, which can also improve safety, reduce the labor intensity, ensure product quality and process stability.
Research on Warpage of Polystyrene in Selective Laser Sintering
Authors: Wang C.Y. , Dong Q. , Shen X.X.
Published: December 2010

Warpage is a crucial factor to accuracy of sintering part in selective laser sintering (SLS) process. In this paper, The influence of process parameters on warpage when sintering polystyrene(PS) materials in SLS are investigated. The laser power, scanning speed, hatch spacing, layer thickness as well as temperature of powder are considered as the main process parameters. The results showed that warpage increases with the increase of hatch space. Contary to it, warpage decreases with the increase of laser power. Warpage decreases with the increase of layer thickness between 0.16~0.18mm and changes little with increase of the thickness. Warpage increases along with the increase of scanning speed but decreases when the speed is over about 2000mm/s. When the temperature changes between 82°C-86°C, warpage decreases little with the increase of temperature. But further increase of temperature leads to warpage decreasing sharply when the temperature changes between 86°C-90°C.
Development and Status Quo of High-Speed Cutting
Authors: Li Yong Xiang , Wang Dong Xia , Wu Wen Bin
Published: December 2010

High-speed cutting (HSC) is a practical technique of advanced manufacturing technology, leading the development of cutting and machining. This paper discusses the mechanism of HSC and the worldwide status quo, application and prospects of HSC.
Research on Structure and Control System of Laser Surface Texturing Machine
Authors: Zhang Pei Yun , Wang Mu Ju , Jin Yue , Hua Xi Jun , Fu Yong Hong , Sheng Zhan Shi , Ji Wei , Fu Hao
Published: December 2010

Existing laser honing machines all utilize the motion mode of workpiece movement. But as to complex workpiece, this mode is inappropriate to use. For example, cylinder liner, pre-casted into the engine block, is not suitable to rotate when fixed on the chuck, because the block is irregular and heavy. This equipment uses the mode of laser head rotation and linear motion. The workpiece keeps still during the laser texturing process. In this paper, the structure design and control principle of the laser machine are narrated in detail. The process of the machine is a new method of laser micro-texturing, named as “single-pulse interval of the same point many times”. The method contributes to processing microscopic or macroscopic morphology and significantly reduces the negative thermal effects of laser processing
Numerical Simulation of Fatigue Life on MSC.Fatigue and ABAQUS
Authors: Zhang Jie , Gu Xiang , Ye Hai Wei , Li Kang Wen
Published: December 2010

Laser Shock Processing (LSP) is a kind of new surface hardening technology, which can increase fatigue life obviously. Due to the LSP, the residual stress is generated and dislocations increase obviously in the surface of specimen, so the fatigue life of specimen processed by LSP increases. Thanks to the finite element programs, it is able to simulate the fatigue life. The simulation of fatigue life has important significance, which not only can reduce the costs of fatigue test and research, but also further study the effect of LSP on fatigue life. The results of fatigue test coincide with the results of simulation.
Research of Virtual Machining Technology of Laser Processing Robot with Multi-Degree of Freedom
Authors: Dong Feng , He Wen Yuan , Gu Jun
Published: December 2010

To reduce the development cost of the laser processing Robot system and improve its machining procductivity, the virtual machining technology of laser processing Robot with Multi-DOF(degree of freedom) is developed in this paper. The whole virtual system structure is designed. In the first stage the MATLAB-GUI (graphical user interface) technology is applied to design the simulation software to simulate the motion of the multi-DOF robot arms in three-dimension by setting the relevant parameters through the software interface. Fruther more, another important function is the inspection of the working space of robot arms, which can be used to determine whether there are any empty spaces or cavities that the robot arms cannot arrive.
Study on the Data Stream Mining and its Application Facing the Mobile Environment
Authors: Gu Ji Nan , Li Guo Jing
Published: December 2010

the striving development of mobile business and the wide use of mobile equipment have enlightened the requirement of high efficient analyst instrument of data stream. Mobile data mining is under the environment of pervasive and finds the knowledge from the continuous data stream. We apply the mining technology of data stream to mobile environment and discuss the algorithm. And we introduce the concrete idea and steps of mobile data mining on the base of improved data stream disposing model. At last, we introduce the application instance that is the application of mobile ERP.
Nonlinear Dynamic Analysis of Back-Rest System of Type WG-2000 Air-Jet Loom
Authors: Sun Lang , Feng Zhi Hua , Wang Si Yong
Published: December 2010

The dynamic model of the back-rest system of type WG-2000 air-jet loom is set up and the relevant nonlinear vibration analysis is investigated when principal parametric resonance is taken into consideration. Results show that the system will be unstable when the corresponding frequency of the rotating-speed meets Ω≈2ω0/n, it may have unstable region. The higher speed is, the wider the region is. The nonlinear dynamic analysis of the back-rest system can be benefit for engineering design and improvement of weaving technology.
Research of Service-Oriented Complex Product Cooperated Development Method
Authors: Wu Wei Dong , Liao Wen He
Published: December 2010

Facing the characteristics of complex product, lead service-oriented thought into the development of complex products, and bring out the method of service-oriented complex product development. The service-oriented complex product development system is researched, and its construction is given out. The characteristics of development resource of service-oriented complex product are summarized; the conception of service-oriented complex product development (SOCPD) is given out, combined with the characteristics of complex product development, SOA, ESB are studied. The net-shaped organization of complex product development is demonstrated。The description of the development process of service-oriented complex product is provided, and the service chain of complex product is expounded.
PCA for Leukemia Classification
Authors: Li Jing , Weng Gui Rong
Published: December 2010

The real cause of leukemia has not been found, and traditional method to recognize the malignant cells has some limitations, and that is very time-consuming. Because microarray gene expression data is few samples, high-dimensional and nonlinear, it brings us “dimensionality disaster”, so data dimensionality reduction becomes a problem we pay attention, and SVM (Support Vector Machine) overcomes the “dimensionality disaster” to a certain extent by means of optimization method, for the decision function of SVM is only decided by part of the support vectors. This paper combines SVM with Laplacian Eigenmaps and PCA (Principal Component Analysis) respectively for Leukemia data classification, compare the results, PCA gets better result.
Application of Fuzzy Theory in Evaluation of the University Entrance Art Examination Grade
Authors: Li Han , Rui Xiao Guang , Jiang Xiao Mei
Published: December 2010

How to score professional papers of university entrance art examination scientifically and correctly has been one of the concerns of the staff in scoring the art paper. This paper proposed and constructed the model of fuzzy comprehensive evaluation on art professional papers based on fuzzy theory aimed at many ambiguous factors in art papers under general requirements for visual effects in scoring process. The scoring experimental research was implemented on art professional papers using the scoring model and satisfactory results obtained. Therefore the theoretical and experimental basis was laid for practical application of the method.
The Inner Equilibrium Analysis and Counterweight Design of Engine
Authors: Yuan Xia , Wang Tie , Fan Wen Xin
Published: December 2010

Firstly the engine models with different types of crankshaft are built, and the load condition of the crankshaft is simulated .After comparing the simulation results, a conclusion is obtained that the model with beam crankshaft or flexible crankshaft corresponds with actual situation. Then the selection of the balance target is discussed .At last, using a certain 60°V8 engine as an example, two kinds of counterweight arrangement schemes are studied, and the simulation results shows that both schemes can achieve good balance effect.
Research on Bionic Hive Modularization Technology of Disassembly
Authors: Wang Wei Lin , Zhang Jia Tai
Published: December 2010

Aiming at the characteristics of optional disassembly problem, disassembly strategy based on bionic disassembly hive model is presented in this study. This method is combined with modular theory to resolve the data explosion which is caused by too many parts in disassembly body for relevant algorithms. Through establishing disassembly hive space model, the judgment of disassembly direction and some other problems are transferred into the evaluation of ant bee groups’ migration routes. The relative disassembly difficulty of the part is defined based on the conception of disassembly ring. And new ideas of obtaining disassembly sequence are introduced to improve the efficiency of getting disassembly programs.
Research on Reed-Solomon Code in Complementary Code Keying Modulation Technology
Authors: Su Xi , Bai Peng , Feng Yan Ping , Wu Yuan Yuan
Published: December 2010

As the high speed expanding scheme adopted by IEEE802.11b standard, the Complementary Code Keying modulation technology can only perform well in error probability with high signal noise ratio. However, when SNR is comparably low or the number of users in the same channel augments suddenly, the system’s error probability soars. On the basis of the research on Complementary Code Keying, RS coding and decoding algorithms, this paper analyzed code parameters’ influence on error correction and accordingly promoted a coding scheme suitable for Complementary Code Keying: RS（255,239）. Simulation Results demonstrated that once SNR is upon 5.1dB the system performance would be greatly enhanced.
Machining Error Analysis and its Compensation Using Fuzzy Inference in Crankshaft Non-Circular Grinding
Authors: Shen Nan Yan , Fang Ming Lun , Li Jing , He Yong Yi
Published: December 2010

The error sources, including technological system, numerical control system and motion control model, generate a machining error in the radial direction of the crankpin which varies with the rotating angle of the crankshaft journal in crankpin non-circular grinding. This machining error can be reduced in advance through giving the additional impulses as the displacement correction of grinding carriage to numerical control system. However due to the strong nonlinearity of non-circular grinding system, the machining error of crankpin is difficult to be described precisely by a certain mathematic model. In this paper, a compensation method is proposed, which utilizes the measured error after the last grinding circle and the change of error to find the initial compensation value in the next grinding circle by fuzzy reasoning. To increase the self-learning ability of this method, the final compensation value in the next circle is composed of the initial value and the final value in the last circle. The grinding experiments results show that the roundness error can be reduced into the expectation in only a few grinding circles by this method, which demonstrates its high efficiency and applicability.
A Linear-Encoder-Based Displacement Sensing Approach for Cost-Sensitive Applications
Authors: Li Qi Peng , Fang Ping
Published: December 2010

A new low-cost displacement sensing approach is put forward. It employs physical multiplication by using multiple linear encoders and differential grating codestrips, and the differential phase configuration is mechanically guaranteed; furthermore, a flash signal processing circuit comprising time sequence generator, counter and D/A with no microprocessors involved is also developed. Theoretical analysis is presented, and a test system using Heds-9730 as the detecting unit is built, and then experiments on an electromagnetic actuator are carried out. The measured results agreed well with the original, and the results prove that the sensing approach can achieve high sampling rate, high resolution and cost saving, thus providing an effective displacement measuring means for cost-sensitive applications.
Fault Diagnosis to Mid-Size Excavator Hydraulic System Based on Fault Tree Analysis
Authors: Ma Chi , Wang Ke She , Sun Jiang Hong
Published: December 2010

Analyzes slewing hydraulic system of hydraulic excavator by fault tree analysis. According to logical relationship of slewing hydraulic system structure, draws fault tree. Finishes qualitative and quantitative analysis. Divides the minimum cut sets. Calculates the reliability of the whole system in order to find the weakest link. Puts forward ways to increase the reliability.
Application of Stereographic Projection in the Search of Key Block of Surrounding Rock Mass for Underground Powerhouse
Authors: Wang Zhong Chang
Published: December 2010

The rose diagram of joint is generalized by grouping the attitude of disclosed discontinuous faces in detecting cavern and measuring point coordinate. The search of movable and key blocks of surrounding rock mass for underground powerhouse is implemented, the combinations of discontinuous faces and sliding faces, the location and the parameter of stability of movable and key blocks are obtained by used of the method of stereographic projection and vector analysis of the block theory. It is shown that the numbers of movable and key blocks in the location of downriver right side wall and vault are larger than those in other location owing to numerous discontinuous faces, and the faults of F34 and F33 play a main role in the stability of movable and key blocks. The guidance for excavation and reinforce of underground caverns is provided.
Inversion of Initial In Situ Stress Field by the Method of Multivariate Analysis and Engineering Application
Authors: Yue Xiao Lei , Li Yong , Wang Han Peng
Published: December 2010

Based on engineering geological conditions and measured data of the in-situ stress at a hydropower station, 3D geological models under each affecting factor are calculated by means of finite element computing tools ABAQUS and MATLAB. Then, a multivariate regression model is created between the measured and calculated value of in-situ stress at measurement points, and the optimal regression coefficient of the model is found. Consequently, the distributions of initial in-situ stress of this area are obtained. It is the first time to take into account the independence and internal relations among each stress components. Thus, the more reasonable distributions of initial in-situ stress of this area are obtained. The results indicate that the 3D calculating in-situ stress field is reasonable.
The Simulation of Heat Pipe Evaporator in Concentration Solar Cell
Authors: Wang Zi Long , Zhang Hua , Zhang Hai Tao
Published: December 2010

Considering the problem of the concentrating solar cell efficiency restricted by the temperature. The closed two-phase thermosyphon was used to dissipation heat in concentrating solar cell at high heat flux, which adopted water as the working fluid. The temperature distribution of evaporator had significant effect on solar cell performance and heat pipe efficiency. A numerical simulation model of evaporator was established by FLUENT. During the computing process, the heat flux, filling ratio of liquid and saturation temperature were taken into account. It was found that the maximum temperature of evaporator was less than 85°C, when the solar cell operated in 140 to 180 suns, in the conditions of evaporator size (Length×Width×Height, 100×100×30 mm), the optimum charging ratio of liquid is between 27%～30%. The smaller saturation temperature would bring the better heat transfer characters.
Electromagnetic Interference’s Effect on the Performance of Electro-Hydraulic Control System
Authors: Zhang Kai , Li Wan Li , Li Jian , You Zhang Ping
Published: December 2010

The performance of engineering machinery and equipments will be affected under the environment of unstable electromagnetic fields. In the magnetic field, with focusing on the proportional solenoid of a certain engineering machinery hydraulic proportional control system, the internal changes of characteristics in the magnetic field lead to the changes of force output characteristics through output changes in air gap magnetic flux, and the instantaneous output performance is affected by electromagnetic interference. The electromagnetic environment’s effect on the changes of electro-hydraulic control system is determined by implementation of the proportional solenoid electromagnetic interference. The result shows that the control performance of mechanical hydraulic control system becomes unstable, and the anti-electromagnetic interference capacity of electromagnetic sensitive element in the electro-hydraulic control system should be improved.