Oerlikon Schlafhorst：引领短纤纺纱技术

欧瑞康赐来福公司作为短纤领域的行业标杆，坚持不断创新，潜心致力于最先进纺纱和络筒设备的研发，旨在为客户提供最具经济效益的纺纱和络筒解决方案。     

Biological properties of iron oxide nanoparticles for cellular and molecular magnetic resonance imaging

Superparamagnetic iron-oxide particles (SPIO) are used in different ways as contrast agents for magnetic resonance imaging (MRI): Particles with high nonspecific uptake are required for unspecific labeling of phagocytic cells whereas those that target specific molecules need to have very low unspecific cellular uptake. We compared iron-oxide particles with different core materials (magnetite, maghemite), different coatings (none, dextran, carboxydextran, polystyrene) and different hydrodynamic diameters (20-850 nm) for internalization kinetics, release of internalized particles, toxicity, localization of particles and ability to generate contrast in MRI. Particle uptake was investigated with U118 glioma cells und human umbilical vein endothelial cells (HUVEC), which exhibit different phagocytic properties. In both cell types, the contrast agents Resovist, B102, non-coated Fe(3)O(4) particles and microspheres were better internalized than dextran-coated Nanomag particles. SPIO uptake into the cells increased with particle/iron concentrations. Maximum intracellular accumulation of iron particles was observed between 24 h to 36 h of exposure. Most particles were retained in the cells for at least two weeks, were deeply internalized, and only few remained adsorbed at the cell surface. Internalized particles clustered in the cytosol of the cells. Furthermore, all particles showed a low toxicity. By MRI, monolayers consisting of 5000 Resovist-labeled cells could easily be visualized. Thus, for unspecific cell labeling, Resovist and microspheres show the highest potential, whereas Nanomag particles are promising contrast agents for target-specific labeling.     

Prediction of cure induced warpage of micro-electronic products

Prediction of residual stresses in micro-electronic devises is an important issue. Virtual prototyping is used to minimize residual stresses in order to prevent failure or malfunction of electronic products.Already during encapsulation stresses build up due to polymerization induced shrinkage of the molding compound. Differences in coefficient of thermal expansion of the involved materials cause additional stresses during cooling down from molding to ambient temperature. Since industry is availed by reliable prediction methods, detailed material models are required. In electronic packaging, mechanical properties of most of the involved materials have constant mechanical properties. However, the viscoelastic properties of the encapsulation material depends highly on temperature and degree of cure. Reliable predictions of residual stresses require simulation models which take into account the effect of temperature and conversion level.In this paper, properties of molding compound are discussed which are relevant for the prediction of warpage of micro-electronics products. The models for the individual properties are combined to one single model suitable for finite element simulations. The numerical implementation in finite element code is not standard and is done by using user-subroutines.Validation experiments are performed in order to verify the developed material model which is done by measuring and predicting the warpage of a mold map. A Topography and Deformation Measurement (TDM) device is used to measure the deformations at elevated temperatures in a non-intrusive way such that the developed material model could be validated in a broad range of temperature.Finally, simulations are carried out with simplified material models of molding compound. The results of these simulations are compared with results obtained with the cure dependent viscoelastic model and real warpage data. From these comparisons it is concluded that for reliable prediction of warpage, the cure dependent viscoelastic model is has to be used.     

Ageing in the LHCb outer tracker: Aromatic hydrocarbons and wire cleaning

The LHCb Outer Tracker straw tubes have shown to suffer from gain loss after irradiation in the laboratory at moderate intensities. Under irradiation an insulating layer is formed on the anode wire. The ageing is caused by contamination of the counting gas due to outgassing of the plastifier di-isopropyl-naphthalene in araldite AY103-1 used at construction. This paper presents irradiation results with and without the plastifier, together with the mass spectra of the glue samples. In addition, the effects of wire heating and large currents are presented.     

Synthesis of an extremely stable ceramic in the system Si/B/C/N using 1-(trichlorosilyl)-1-(dichloroboryl)ethane as a single-source precursor

 A new material discovered in the Si/B/C/N system was found to remain in the amorphous state up to a very high temperature of 2000°C. This material, with the composition Si₂B₂N₅C₄, is the only material in this system which does not undergo any microstructural changes until such high temperatures. Furthermore, the substance shows an extremely high resistance to oxidation up to 1500°C. The synthesis of amorphous Si₂B₂N₅C₄ was achieved by using the novel single-source precursor 1-(trichlorosilyl)-1-(dichloroboryl)ethane (TSDE), which can be synthesized in high yields from inexpensive starting materials in a simple single pot reaction. Examination of the structural properties of the pyrolytic ceramic reveals a substructure consisting of tetrahedrally and trigonally-planar coordinated silicon and boron, respectively. Si-C- and B-C-bonds present in the molecular precursor could not be distinguished from Si-N- and B-N-bonds in the fully pyrolized ceramic. EDX and X-ray-diffraction showed the material to have a homogeneous elemental distribution, and no phase separation could be detected. Received: 15 August 1998 / Reviewed and accepted: 24 September 1998     

DFT studies of hydrogen storage properties of Mg0.75Ti0.25

Absorption energies of hydrogen in Mg_0.75Ti_0.25 alloys as a function of the hydrogen concentration were calculated using Density Functional Theory. Four types of structures of alloys and their hydrides including TiAl₃, ZrAl₃, AuCu₃, and segregated types of structures were considered. The stability of the configurations, and the structural and electronic bonding properties were studied. The hydrogenation properties depend highly on the structure of the alloys. The ordered alloys have very similar properties to that of pure Mg. For segregated alloys, the hydrogenation properties can be divided to Ti-like, ordered alloy-like and Mg-like from low to high hydrogen concentration. The formation energies show that for the four structures, segregated Mg_0.75Ti_0.25 is favored for alloys, whereas TiAl₃ type of Mg_0.75Ti_0.25H₂ are favored for hydrides. Therefore hydrogen induced structural rearrangement of the intermetallic structures of the Mg_0.75Ti_0.25 might occur upon hydrogen cycling. For the non-homogenous Mg-Ti-H system, further phase segregation of Ti in Mg might occur. Partial dehydrogenation with some hydrogen remaining in the Ti-rich region may improve reversibility.     

Effects of exercising before versus after eating on dieting and exercise evaluations: A preliminary investigation.

Psychological processes may play a role in the evaluation of the effectiveness of exercise and subsequent food intake. In order to further investigate this phenomenon, the effects of the timing of exercise relative to an eating opportunity were evaluated. Female undergraduate participants who were of average weight and did not exercise regularly were randomly assigned to one of three conditions (exercise before eating [n = 10], exercise after eating [n = 11], or no exercise [n = 12]). Expectations of the effectiveness of the exercise, value of dieting, and intake were assessed. Participants who exercised after eating had higher expectations of the effectiveness of the exercise than those who exercised before eating, while those who exercised before eating reported valuing dieting more than controls. No effects on intake emerged; therefore, there appears to be a disconnect between dieting appraisals and actual eating behaviour. The results are discussed in relation to theories on conflicting goals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Approximation Algorithms for Scheduling with Reservations

We study the problem of non-preemptively scheduling n independent sequential jobs on a system of m identical parallel machines in the presence of reservations, where m is constant. This setting is practically relevant because for various reasons, some machines may not be available during specified time intervals. The objective is to minimize the makespan C _max, which is the maximum completion time.     

Trimming of Graphs, with Application to Point Labeling

For t>0 and g≥0, a vertex-weighted graph of total weight W is (t,g)-trimmable if it contains a vertex-induced subgraph of total weight at least (1−1/t)W and with no simple path of more than g edges. A family of graphs is trimmable if for every constant t>0, there is a constant g≥0 such that every vertex-weighted graph in the family is (t,g)-trimmable. We show that every family of graphs of bounded domino treewidth is trimmable. This implies that every family of graphs of bounded degree is trimmable if the graphs in the family have bounded treewidth or are planar. We also show that every family of directed graphs of bounded layer bandwidth (a less restrictive condition than bounded directed bandwidth) is trimmable. As an application of these results, we derive polynomial-time approximation schemes for various forms of the problem of labeling a subset of given weighted point features with nonoverlapping sliding axes-parallel rectangular labels so as to maximize the total weight of the labeled features, provided that the ratios of label heights or the ratios of label lengths are bounded by a constant. This settles one of the last major open questions in the theory of map labeling.     

Psychologists' roles and opportunities in rehabilitation and recovery for serious mental illness: A survey of Council of University Directors of Clinical Psychology (CUDCP) clinical psychology training and doctoral education.

The emergence of psychiatric rehabilitation and the recovery movement generate new and expanded roles for psychologists in services for people with serious mental illness (SMI). However, the proportion of psychologists working in SMI services today is substantially less than previous decades. This article reviews the roles of psychologists in various mental health systems and outlines the contributions that psychologists can make in implementing evidence based approaches for people with SMI. A survey of American Psychology Association (APA)-accredited Council of University Directors of Clinical Psychology (CUDCP) Clinical Psychology doctoral programs was conducted. The results of the survey indicate an increase, since the early 1990s, in clinical faculty with SMI interests, and suggest that many graduate programs provide opportunities for SMI-relevant research and practicum training. However, the survey also indicates a lack of coursework on topics relevant to SMI and a lack of coursework relevant to assuming administrative and leadership roles in the mental health system. Despite training opportunities in graduate school, production of new PhDs who choose the SMI field is unlikely to meet the demand. According to the present study, the limiting factor is not availability of training, but student career choice. The opportunities and challenges that psychologists face in SMI recovery-oriented service delivery are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)