上颌窦三维实体模型的重建

使用了一种新的基于CT、MRI等医学影像数据的三维实体模型重建方法。首先对医学影像数据进行阈值分割,提取出需要重建的部分,并重建成为STL格式文件。然后提取出STL文件的顶点得到点云,对点云进行分割,分别重建曲面。最后,将重建得到的曲面进行修剪,并添加所需要的结构,得到三维实体模型。     

Experimental Investigation and Thermodynamic Description of the Cu-Zr System

The Cu-Zr binary system is re-investigated via experiment and thermodynamic modeling. Four alloys were prepared by arc melting in order to check the controversial phase equilibria reported in the literature. Both as-cast and annealed alloys were examined by optical microscopy, x-ray diffraction and electron probe microanalysis, and the phase transformation temperatures were measured by differential scanning calorimetry. The intermetallic compounds, Cu₂₄Zr₁₃, Cu₂Zr and Cu₅Zr₈, were demonstrated to be not the stable phases. Based on the literature information and present experimental data, the Cu-Zr system was critically evaluated by means of CALculation of PHAse Diagram approach. A set of self-consistent thermodynamic parameters was obtained, and the calculated phase diagram and thermodynamic properties are in a satisfactory agreement with the experimental data.     

High-Throughput Determination of Interdiffusion Coefficients for Co-Cr-Fe-Mn-Ni High-Entropy Alloys

In this report, a combination of the diffusion multiple technique and the recently developed pragmatic numerical inverse method was employed for a high-throughput determination of interdiffusivity matrices in Co-Cr-FeMn-Ni high-entropy alloys (HEAs). Firstly, one face-centered cubic (fcc) quinary Co-Cr-Fe-Mn-Ni diffusion multiple at 1373 K was carefully prepared by means of the hot-pressing technique. Based on the composition profiles measured by the field emission electron probe micro analysis (FE-EPMA), the composition-dependent interdiffusivity matrices in quinary Co-Cr-Fe-Mn-Ni system at 1373 K were then efficiently determined using the pragmatic numerical inverse method. The determined interdiffusivities show good agreement with the limited results available in the literature. Moreover, the further comparison with the interdiffusivities in the lower-order systems indicates the sluggish diffusion effect in Co-Cr-Fe-Mn-Ni HEAs, which is however not observed in tracer diffusivities. In order for the convenience in further analysis, a generalized transformation relation among interdiffusivities with different dependent components in multicomponent systems was finally derived.     

ASTUDY OF VALENCE OF YTTRIUM IN Y_2O_3 Mo CATHODE

１．ＩｎｔｒｏｄｕｃｔｉｏｎＡｓａｎｅｗｋｉｎｄｏｆｒａｒｅｅａｒｔｈｍｏｌｙｂｄｅｎｕｍｃａｔｈｏｄｅｍａｔｅｒｉａｌ,ＭｏＹ２Ｏ３ｉｓｅｘｐｅｃｔｅｄｔｏｓｕｂｓｔｉｔｕｔｅｒａｄｉｏａｃｔｉｖｅＷＴｈＯ２ｃａｔｈｏｄｅｍａｔｅｒｉａｌｓｉｎｔｈｅｆｕｔｕｒｅ．Ｍｏ４ｗｔ％Ｙ２Ｏ３ａｌｌｏｗｓ,ｒｅｌａｔｉｖｅｔｏＭｏＬａ２Ｏ３〔１２〕（ｗｈｉｃｈｈａｓｂｅｅｎｗｉｄｅｌｙｓｔｕｄｉｅｄｓｉｎｃｅ１９７０ｓｉｎｏｒｄｅｒｔｏｓｕｂｓｔｉｔｕｔｅＷＴｈＯ２ｃａｔｈｏｄｅｍａｔｅｒ…     

Weldability and microstructural variations in weldments of Ti-5Ta-1.8Nb alloy

The successful replacement of the present generation of corrosion-resistant materials (nitric acid-grade stainless steel and Ti) by Ti-5Ta-1.8Nb, which has better corrosion resistance, depends on its weldability characteristics. This article presents the results of a study on the fabrication, qualification, and microstructural characterization of the welds. Welding was carried out using the direct current electrode negative (DCEN) polarity tungsten inert gas (TIG) (manual) welding method with high-purity Ar shielding. Testing was carried out as per the ASME standard (section IX, welding and brazing). Qualification tests found that the weldment met the required properties. The weldment showed heterogeneous microstructures, which are rationalized based on differences in phase transformation mechanisms that are dictated by the thermal cycles experienced by various microscopic regions. The results, described in this article, confirm that the weldability of the developmental Ti-Ta-Nb alloy is excellent. A preliminary evaluation of the corrosion behavior of the welds showed rates comparable to that of the base metal, establishing that this alloy could be considered as an alternative material for use in highly corrosive environments.     

Template-free hydrothermal synthesis of single-crystalline SnO<Subscript>2</Subscript> nanocauliflowers and their optical properties

Large-scale single-crystalline SnO₂ nanocauliflowers were successfully synthesized using a hydrothermal growth method without any template. The samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and selected area electron diffraction (SAED). FE-SEM images show that the as-grown SnO₂ nanocauliflowers are constructed of tetragonal prisms with a width of 500–600 nm. XRD, EDS, and SAED results indicate that the as-grown SnO₂ nanocauliflowers are single crystalline with the tetragonal rutile crystalline structure. The growth mechanism of SnO₂ nanocauliflowers is also preliminarily discussed on the basis of different Sn(OH)₆²⁻ concentrations, and it is found that Sn(OH)₆²⁻ concentration plays an important role in determining the shape of the prepared SnO₂. Room temperature photoluminescence was further carried out on SnO₂ nanocauliflowers to investigate their optical properties. An intense blue luminescence centered at a wavelength of 424 nm is observed in the as-grown SnO₂ nanocauliflowers.     

Manufacturing and measurement of freeform optics

Freeform optics is the next-generation of modern optics, bringing advantages of excellent optical performance and system integration. It finds wide applications in various fields, such as new energy, illumination, aerospace and biomedical engineering. The manufacturing of freeform optics is an integrated technology involving optical design, machining, moulding, measurement and characterization. This paper surveys the current application status and research on major technologies in details.     

A study of job shop standard setup time quota

For the multi-item and small lot size production mode and single machine job shop scheduling sequence independent setup time, many setup times are difficult to estimate accurately, which influences the ability to achieve accurate production cycles and costs of products. The survey shows that the length of the setup time depends on the level of employee’s knowledge. Therefore, a method for determining the standard setup time quota based on the level of employees’ knowledge is proposed. First, an evaluation index system for the level of employee’s knowledge is built; the level of employee’s knowledge is estimated by the masses and experts fuzzy comprehension evaluation and entropy method. Second, the range and definition of the level of employees’ knowledge index are developed. Third, the relational model of the employee’s knowledge level and the level of employees’ knowledge index is constructed through the least squares method. Finally, an example application is presented to verify the feasibility and effectiveness of the proposed model.     

Soluble Epoxide Hydrolase and Diabetes Complications

Type 2 diabetes mellitus (T2DM) can result in microvascular complications such as neuropathy, retinopathy, nephropathy, and cerebral small vessel disease, and contribute to macrovascular complications, such as heart failure, peripheral arterial disease, and large vessel stroke. T2DM also increases the risks of depression and dementia for reasons that remain largely unclear. Perturbations in the cytochrome P450-soluble epoxide hydrolase (CYP-sEH) pathway have been implicated in each of these diabetes complications. Here we review evidence from the clinical and animal literature suggesting the involvement of the CYP-sEH pathway in T2DM complications across organ systems, and highlight possible mechanisms (e.g., inflammation, fibrosis, mitochondrial function, endoplasmic reticulum stress, the unfolded protein response and autophagy) that may be relevant to the therapeutic potential of the pathway. These mechanisms may be broadly relevant to understanding, preventing and treating microvascular complications affecting the brain and other organ systems in T2DM.