Groove Microstructure Research Articles

Fabrication and performance evaluation of PAA/TiO2 self-assembled multilayers

Strip groove microstructure simulated sharkskin has been prepared on the surface of hydroxylated PDMS by using TiO2/polyacrylic acid (PAA) composite self-assembled technique and thermal stress. The depth changes from 50 to 200 nm by increasing the thickness of self-assemble layers. The span spacing was about 1–3 μm. Strip groove microstructure morphology inhibited more than 66% diatom attached to the surface of PDMS. The double layers have the highest inhibition with 78%. All specimens have no barnacle larva attached.

Microstructure design and analysis of rotor and stator in three-phase permanent magnet brushless direct current electric motor with low rare earth material

Various hemicycle groove microstructures of surface permanent magnets and tooth surface stators are simulated to improve the motor performance by a finite-element analysis software in this study for designing, analysing and optimising and observation of the magnetic field strength distribution and to reduce the cogging torque in the permanent magnet brushless direct current motors. The output torque variation in the surface permanent magnet brushless direct current motor does not vary much or varies by a no more than 10% decrement in the situation of decreasing magnetic field strength while reducing the permanent magnet volume. The cogging torque of the optimal combination of the surface permanent magnet brushless direct current motor can be abated 62·4%, but the output torque is only decreased by 6·5% approximately because the usage amount of the rare earth permanent magnet volume in the designed surface permanent magnet brushless direct current motor is reduced by 5·3%. Finally, a prototype of the three-phase radial-flux surface permanent magnet brushless direct current motor with low rare earth material has been manufactured to verify the optimal simulation design.

Assessment of gastric phenotypes using magnifying narrow-band imaging for differentiation of gastric carcinomas from adenomas.

Background. Conventional white-light endoscopy and forceps biopsy are insufficient for definitive diagnosis of gastric adenoma. Immunohistochemical studies have reported an obvious phenotypic difference between adenomas and carcinomas. We investigated the utility of narrow-band imaging with magnifying endoscopy (NBI-ME) for mucin phenotypic assessment to differentiate carcinomas from adenomas. Methods. NBI-ME findings were classified into A, B, and AB types, which revealed papillary, tubular pits and groove microstructures, respectively. To investigate A-B classifications retrospectively, 137 patients (155 lesions) that were diagnosed pretherapeutically with adenoma or borderline lesions by biopsy were enrolled. The mucin phenotype was analyzed immunohistochemically in the first 60 lesions. Results. After endoscopic submucosal dissection, A type and AB type lesions were determined histologically as carcinoma (81/82, 99%). B type lesions were adenoma (29/73, 40%) and carcinoma (44/73, 60%). A or AB type correlated to histological carcinomas (sensitivity 65%, specificity 97%, and accuracy 71%). Mucin phenotypes were gastric or gastrointestinal in A type and AB type carcinomas (31/37, 84%) and intestinal in B type adenomas and carcinomas (21/23, 91%). Conclusions. NBI-ME has the advantage of the assessment of mucin phenotypes in gastric carcinomas and adenomas. The proposed A-B classification is useful, especially for differentiation of gastric or gastrointestinal carcinomas from adenomas.

Microstructure Design of Surface Permanent Magnet and Tooth Surface Stator in Brushless DC Motor with Low Rare Earth Material

Permanent magnet (PM) brushless DC motors (BLDCMs) are widely applied in industrial drives. However, the price rising of rare earth resource resulted in country policy restriction, so it is detrimental for mass production of PM-BLDCMs. As a result, the design and manufacture tendency of PM-BLDCMs are smaller and slighter in adopting rare earth materials of PMs. Additional, the magnetic flux density of PMs are difficult to improve in the near future. The effective method is to decrease stator reluctance and to adjust magnetic flux distribution of the air gap in stator design. Hence, the surface permanent magnets (SPMs) and tooth surface stators (TSSs) are designed to improve the motor performance, and are calculated by finite-element analysis (FEA) software in this study. Various hemicycle groove microstructures of SPMs and TSSs for designing, analyzing and optimizing are considered to observe the magnetic field strength distribution and to reduce the cogging torque in PM-BLDCMs, and the FEA result can be regarded as important references of motor structure design. The cogging torque can be reduced 80.9% in SPM3-model and can be decayed 89.2% in TSS2-model versus original model separately, and the cogging torque of the optimal combination of SPM-BLDCM can be abated 62.4%. Furthermore, the usage amount of rare earth material volume in designed SPM-BLDCMs can be reduced 5.3% in average. Finally, a prototype of the SPM- BLDCM has been constructed to prove the simulation design.