基于工业CT扫描的材料内部裂纹表征与分析

针对材料损伤过程中内部裂纹缺陷的表征,采用工业CT (Computed Tomography)对含有内部裂纹的试样进行扫描,获得了裂纹三维方向灰度切片图像,借助MATLAB+ImageJ软件对裂纹阈值、面积分布和扩展路径等特征进行了定量表征分析和拟合。结果表明裂纹面积分布呈对称趋势,采用四项式可较好拟合裂纹面积特征分布规律,采用累加法计算裂纹体积为76.83 mm3,与积分法计算相对误差为0.48%;相邻切片裂纹面积差值绝对值小于5的占59.26%,此区间裂纹区变化较为均匀;主视图裂纹体沿两侧扩展路径呈现不一致趋势,分别采用Gauss函数和Logistic函数对两侧路径A、B进行拟合,拟合度因子R2分别为0.9928和0.9968,拟合精度较高;同时,主视图裂纹体两侧路径差值的3个峰值,将差值散点图分为3个阶段,其中阶段二差值呈线性增长。     

一种改善LED背光亮度均匀性的新型反射膜研究

在LCD的LED背光腔体的底面设计了新型曲面形状及性能的反光膜,将扩散膜反射回灯腔底部的光重新反射回出光口以改善亮度均匀性能;在侧面设计了镜面反射膜,将位于LED矩阵边缘区域由LED射向灯腔侧壁的光反射重新射向出光口,增加了LED背光边缘区域的亮度,从而改善了背光边缘区域较暗的亮度不均匀状况.根据此类反射膜的设计完成了反射膜的制备,并应用于38 cm LED背光源样品.测试结果显示,设置反射膜的LED背光的亮度均匀性值为10.2%,明显优于未设置反射膜的值16.8%,亮度提高了29%左右,表明该种新型反射膜可以提高亮度并改善亮度均匀性.     

Comprehensive Utilization of Paigeite Ore Using Iron Nugget Making Process

 The feasibility of paigeite ore treatment with iron nugget making process is proved. The isothermal reduction experiments at laboratory scale were carried out, using carbon bearing pellets which were made of boron containing iron concentrate and pulverized coal mainly, from 1623 to 1723 K with different heating time. The results indicated that iron nugget making process depends mainly on heating time and temperature. And the iron nugget and slag can separate in a clean manner at 1673 K for 15 min. For the iron nugget, the C content is 357% (mass percent) and B is 0065% (mass percent). The B2O3 content of slag is 2001%, and the boron was concentrated into one phase which is identified as suanite (Mg2B3O5) during the solidification. With an extraction ratio of 80% under the atmospheric conditions, the activity of boron in slag is good. The boron-rich slag can be used to extract boric or boric acid and alleviate the shortage of boron resource. Through series of calculation and analysis related, it can be concluded that the recovery ratio of Fe and boron are about 98% and 97% respectively. The results show that this method is feasible and effective on the utilization of paigeite ore.     

Choosing hamsters but not rats as a model for studying plasma cholesterol‐lowering activity of functional foods

Rats and hamsters are commonly used rodents to test the efficacy of cholesterol‐lowering functional foods. In general, a diet containing 1% cholesterol for rats whereas a diet containing 0.1% cholesterol for hamsters is used to induce the hypercholesterolemia. The present study was carried out to compare hamsters with rats as a hypercholesterolemia model. Golden Syrian hamsters and Sprague Dawley rats were randomly divided into four groups and fed one of the four diets containing 0–0.9% cholesterol. Results demonstrated that serum total cholesterol (TC) in hamsters was raised 73–81% higher than that in rats fed the same cholesterol diets. Unlike rats in which HDL‐C accounted very little for serum TC, the lipoprotein profile in hamsters was closer to that in humans. We investigated interaction of higher cholesterol diets with 3‐hydroxy‐3‐methylglutary‐CoA (HMG‐CoA) reductase, low‐density lipoprotein receptor (LDL‐R) and cholesterol‐7α‐hydroxylase (CYP7A1), sterol regulatory element binding protein‐2 (SREBP‐2), and liver X receptor (LXR‐α). Results showed hamsters and rats metabolized cholesterol differently. In view that hamsters synthesize and excrete cholesterol and bile acids in a manner similar to that in humans, it is concluded that hamsters but not rats shall be chosen as a model to study efficacy of cholesterol‐lowering functional foods.     

Chiral 1,2,3,4‐Tetrahydro‐1‐naphthylamine‐Derived Phosphine‐Phosphoramidite Ligand (THNAPhos): Application in Highly Enantioselective Hydrogenations of Functionalized CC Bonds

We have recently reported a new chiral 1,2,3,4‐tetrahydro‐1‐naphthylamine‐derived phosphine‐phosphoramidite ligand, (R_c,R_a)‐THNAPhos, that is highly efficient in the rhodium‐catalyzed asymmetric hydrogenation of a broad range of α‐enol ester phosphonates. To further demonstrate the utility of THNAPhos in asymmetric hydrogenation, in this paper, we describe its new application in the asymmetric hydrogenation of α‐dehydroamino acid esters, enamides, dimethyl itaconate and α‐enamido phosphonates. The results disclosed that the Rh/(R_c,R_a)‐THNAPhos complex is highly effective for the enantioselective hydrogenation of these kinds of functionalized CC olefins, affording the corresponding hydrogenation product in excellent enantioselectivities (normally over 99% ee).     

Broadband emission and flat optical gain glass containing Ag aggregates for tunable laser

Spectroscopic properties of Sm³⁺-doped borate glass with silver aggregates were investigated, and it was found that the glass presented broad excitation and emission band covering violet-infrared region. Furthermore, the optical gain coefficients at various wavelengths were measured via an amplified spontaneous emission technique, it was confirmed that the glass displayed flat net optical gain coefficient in almost full visible region. In addition, the fluorescent temperature quenching of the glass was examined, and it was seen that about 50% of room temperature emission intensity was kept when the sample was heated up to 325°C.     

Antioxidant Activity and Total Polyphenols Content of Camellia Oil Extracted by Optimized Supercritical Carbon Dioxide

In this study, Camellia oil is co-extracted from Camellia oleifera seeds and green tea scraps by supercritical carbon dioxide (SC-CO₂), which is optimized on the extraction yield, ABTS-scavenging activity, and total polyphenols content (TPC) of oil by single-factor experiments combined with response surface methodology (RSM). The extraction temperature, pressure, dynamic time, carbon dioxide (CO₂) flow rate, and seed mass ratio were investigated with single-factor experiments. The results indicated the optimum CO₂ flow rate and dynamic extraction time were 15 L hour⁻¹ and 60 min (i.e., 2.382 kg CO₂/100 g sample). Furthermore, the complicated effects of extraction temperature (40–50 °C), pressure (20–30 MPa), and seed mass ratio (0.25–0.75) were optimized by RSM based on the Box–Behnken design (BBD). The models with high R-squared values were obtained and used to predict the optimum operating conditions of the process. Under the optimum operating conditions (i.e., temperature of 46 °C, pressure of 30 MPa, and seed mass ratio of 0.35), the extraction yield, ABTS-scavenging activity, and TPC of oil were 14.43 ± 0.17 g/100 g sample, 73.70 ± 0.34%, and 2.18 ± 0.05 mg GAE/g oil, which were in good agreement with the predicted values. In addition, the experiments indicated that the Camellia oil obtained was rich in polyphenols, resulting in better oxidation stability and antioxidant activity than the original oil.     

浅析解决煤化工产业水资源缺乏的途径

我国水资源匮乏和煤水资源分布严重不协调的现状使得水资源成为制约煤化工产业发展的重要因素之一,文章论述了采用节水工艺和技术、提高水的再生和回用技术、循环冷却水的零排放、开发无定河地表水资源以及水权转换等方法作为解决煤化工产业水资源匮乏有效途径。     

杨树沟金矿床地质特征及成因探讨

通过对西峡县杨树沟金矿的矿床地质特征进行详细研究,对其成因进行了相关研究和对比。结果表明:杨树沟金矿是典型的与剪切带相关的金矿床。早期受到韧性剪切带作用,随后韧性剪切带经抬升剥蚀构造层次上移,叠加后期的韧—脆性、脆性变形,成矿作用也随之叠加,从而在同一构造部位出现多种矿化类型。在该矿区外围,还有查找这种与剪切带相关的金矿床的巨大潜力。     

Sensitive discrimination and detection of prion disease-associated isoform with a dual-aptamer strategy by developing a sandwich structure of magnetic microparticles and quantum dots

The major challenge of prion disease diagnosis at the presymptomatic stage is how to sensitively or selectively discriminate and detect the minute quantity of disease-associated prion protein isoform (PrP(Res)) in complex biological systems such as serum and brain homogenate. In this contribution, we developed a dual-aptamer strategy by taking the advantages of aptamers, the excellent separation ability of magnetic microparticles (MMPs), and the high fluorescence emission features of quantum dots (QDs). Two aptamers (Apt1 and Apt2), which can recognize their two corresponding distinct epitopes of prion proteins (PrP), were coupled to the surfaces of MMPs and QDs, respectively, to make MMPs-Apt1 and QDs-Apt2 ready at first, which then could be coassociated together through the specific recognitions of the two aptamers with their two corresponding distinct epitopes of PrP, forming a sandwich structure of MMPs-Apt1-PrP-Apt2-QDs and displaying the strong fluorescence of QDs. Owing to the different binding affinities of the two aptamers with PrP(Res) and cellular prion protein (PrP(C)), both of which have distinct denaturing detergent resistance, our dual-aptamer strategy could be applied to discriminate PrP(Res) and PrP(C) successfully in serum. Further identifications showed that the present dual-aptamer assay could be successfully applied to the detection of PrP in 0.01% brain homogenate, about 1000-fold lower than that of commonly applied antibody-mediated assays, which can detect PrP just in 10% brain homogenate, indicating that the present designed dual-aptamer assay is highly sensitive and adequate for clinical diagnosis without isolation of target protein prior to assay.