质量上的最高水准与操作上的方便性--RSB-D 35并条工艺

全球范围内的纺纱厂一直面对着以下挑战和要求: ·为了保持竞争力,必须一直有稳定的纱线质量; ·国际性的竞争要求生产成本不断降低;     

Neutron detection by measuring capture gammas in a calorimetric approach

The neutron capture detector (NCD) is introduced as a novel detection scheme for thermal and epithermal neutrons that could provide large-area neutron counters by using common detector materials and proven technologies. The NCD is based on the fact that neutron captures are usually followed by prompt gamma cascades, where the sum energy of the gammas equals to the total excitation energy of typically 6-9 MeV. This large sum energy is measured in a calorimetric approach and taken as the signature of a neutron capture event. An NCD consists of a neutron converter, comprising of constituents with large elemental neutron capture cross-section like cadmium or gadolinium, which is embedded in common scintillator material. The scintillator must be large and dense enough to absorb with reasonable probability a portion of the sum energy that exceeds the energy of gammas emitted by common (natural, medical, industrial) radiation sources. An energy window, advantageously complemented with a multiplicity filter, then discriminates neutron capture signals against background. The paper presents experimental results obtained at the cold-neutron beam of the BER II research reactor, Helmholtz-Zentrum Berlin, and at other neutron sources with a prototype NCD, consisting of four BGO crystals with embedded cadmium sheets, and with a benchmark configuration consisting of two separate NaI(Tl) detectors. The detector responses are in excellent agreement with predictions of a simulation model developed for optimizing NCD configurations. NCDs could be deployed as neutron detectors in radiation portal monitors (RPMs). Advanced modular scintillation detector systems could even combine neutron and gamma sensitivity with excellent background suppression at minimum overall expense.     

Point cloud reconstruction with sub-pixel accuracy by slice-adaptive thresholding of X-ray computed tomography images

We present a methodology for the calculation of highly accurate point clouds from an image stack obtained with a two-dimensional industrial X-ray computed tomography scanner. The basic idea is to apply a different threshold value to each computed tomography image, which is then used for the calculation of the point cloud. A dense and smooth cloud can be obtained by interpolating the grey values between pixles. Our method combines both. An easy to implement thresholding algorithm is used for the estimation of a slice-by-slice threshold and an interpolating algorithm to reconstruct highly accurate point clouds.It is shown that the point clouds approximate the true dimensions of a scanned part with sub-pixel accuracy.     

信号路径设计

每当我们设计高速的混合信号系统时,我们最好先审视信号路径的每一环节,详细评估各区块的信号失真程度.本文主要介绍输入或接收器路径的设计.发送器或输出路径的设计将会留待以后再详细介绍.典型的接收器或仪表测量系统由信号传感器、模拟信号处理区块、数据转换器、接口及数字处理区块等多个不同环节组成(参看图1).但本文只集中讨论输入路径设计的模拟及混合信号部分.我们必须小心挑选信号路径的各个区块,才可取得预期的成效.     

LOCNET-an experimental communications system using optical routing

Experiences gained with the installation and operation of an experimental communication system are reported. The system uses distributed switching in its narrow-band part, integrating ISDN services and high-speed data communication, and a star coupler as a central device. LiNbO₃ optical switches behind the star coupler prevent line tapping. In the wideband subsystem, optical routing is used for videophone. The central device is a space-division-switching unit consisting of cascaded 4×4 LiNbO₃ switching matrices. Both the narrowband and wideband parts of the system have been operated with bit error rates less than 10^-9     

Videokeratoscope for accurate and detailed measurement of the cornea surface

A videokeratoscope based on the imaging of a gridlike pattern is introduced. Unlike conventional videokeratoscopes that rely on Placido disks, the new measurement principle allows an exact reconstruction of the surface and the display of fine details. The experimental instrument was tested on precision glass spheres; the maximum error of the height data was less than 3 microm. The sensitivity and the potential to resolve fine details were demonstrated with irregular surfaces of specially prepared contact lenses. Structures with height deviations of 0.1 microm are well identifiable. The eyes of 18 individuals were investigated, and fine structures were found on these cornea surfaces. Conventional videokeratoscopes do not resolve such detail.     

Biomimetic mineral-organic composite scaffolds with controlled internal architecture

Bone and cartilage generation by three-dimensional scaffolds is one of the promising techniques in tissue engineering. One approach is to generate histologically and functionally normal tissue by delivering healthy cells in biocompatible scaffolds. These scaffolds provide the necessary support for cells to proliferate and maintain their differentiated function, and their architecture defines the ultimate shape. Rapid prototyping (RP) is a technology by which a complex 3-dimensional (3D) structure can be produced indirectly from computer aided design (CAD). The present study aims at developing a 3D organic-inorganic composite scaffold with defined internal architecture by a RP method utilizing a 3D printer to produce wax molds. The composite scaffolds consisting of chitosan and hydroxyapatite were prepared using soluble wax molds. The behaviour and response of MC3T3-E1 pre-osteoblast cells on the scaffolds was studied. During a culture period of two and three weeks, cell proliferation and in-growth were observed by phase contrast light microscopy, histological staining and electron microscopy. The Giemsa and G?m?ri staining of the cells cultured on scaffolds showed that the cells proliferated not only on the surface, but also filled the micro pores of the scaffolds and produced extracellular matrix within the pores. The electron micrographs showed that the cells covering the surface of the struts were flattened and grew from the periphery into the middle region of the pores.     

On the synthesis of linear control systems with specified characteristics

The Popov invariants are used to define two matrices M_AB and K_AB, which describe the properties of a system $\text{x}\text{?}\text{= Ax + Bu}$ in a basis-independent form. Also a control system with state feedback K and nonsingular input transformation M, $\text{x}\text{?}\text{= (A ? BK)x + BMw = Fx + Gw}$, can be uniquely specified by the corresponding matrices M_FG and K_FG, which may be chosen arbitrarily with the only condition, that (F, G) must have the same unordered set of Kronecker invariants as (A, B). It is shown, how K and M are computed from M_AB, K_AB, M_FG and K_FG. Implications for pole assignment, minimal polynomial assignment and observer design are shown. Also a solution to the minimal realization problem is given, which results in M_AB, K_AB and the output relation y = Cx.     

Sensor fault diagnosis for nonlinear processes with parametric uncertainties

This paper addresses the problem of detecting, discriminating, and reconstructing sensor faults for nonlinear systems with known model structure but uncertainty in the parameters of the process. The convenience of the proposed technique lies in the fact that historical operational data and/or a priori fault information is not required to achieve accurate fault reconstruction except for fixed, short intervals. The overall fault diagnosis algorithm is composed of a series of nonlinear estimators, which estimates parameter and a fault isolation and identification filter. Parameter estimation and fault reconstruction cannot be performed accurately since faults and parametric uncertainty interact with each other. Therefore, these two tasks are performed at different time scales, where the fault diagnosis takes place at a more frequent rate than the parameter estimation. It is shown that the fault can be reconstructed under some realistic assumptions and the performance of the proposed methodology is evaluated on a simulated chemical process exhibiting nonlinear dynamic behavior.     

Targeted Synthesis of Complex Spiro[3H-indole-3,2′-pyrrolidin]-2(1H)-ones by Intramolecular Cyclization of Azomethine Ylides: Highly Potent MDM2–p53 Inhibitors

Mouse double minute 2 (MDM2) is a main and direct inhibitor of the crucial tumor suppressor p53. Reports from initial clinical trials showed that blocking this interaction with a small-molecule inhibitor can have great value in the treatment of cancer for patients with p53 wild-type tumors; however, it also revealed dose-limiting hematological toxicities and drug-induced resistance as main issues. To overcome the former, an inhibitor with superior potency and pharmacokinetic properties to ultimately achieve full efficacy with less-frequent dosing schedules is required. Toward this aim, we optimized our recently reported spiro-oxindole inhibitors by focusing on the crucial interaction with the amino acid side chain of His96_MDM2. The designed molecules required the targeted synthesis of structurally complex spiro[indole-3,2′-pyrrolo[2,3-c]pyrrole]-2,4′-diones for which we developed an unprecedented intramolecular azomethine ylide cycloaddition and investigated the results by computational methods. One of the new compounds showed superior cellular potency over previously reported BI-0252. This finding is a significant step toward an inhibitor suitable to potentially mitigate hematological on-target adverse effects.