Applying wavelet-transform on Internet-based radiologic brain images

Wavelet-transform compression creates high-quality images of small file size by tuning its compression ratio between 10:1 and 80:1. We applied the wavelet-based compression technique to radiologic brain images on the Internet for image display purposes. Wavelet transform compression reduces file size up to 50%. Wavelet transform compression offers the advantage of retaining complete color information in digital images and faster Internet transmission than traditional Joint Photography Experts Group (JPEG) files of equivalent file size. The application of wavelet-based compression technique decreases storage requirements for images on Internet servers.     

In situ analysis of MEA performance under accelerated degradation testing

The durability of proton exchange membrane fuel cells is one of the key issues hindering their widespread commercialization. This study uses the complex accelerating degradation protocol to investigate the performance decay of a membrane electrode assembly. The complex accelerating protocol includes OCV, RH cycling and load cycling. Linear sweep voltammetry, cyclic voltammetry, AC impedance and polarization curves were used to measure key MEA characteristics. The experimental results in this work revealed that the Nafion^® film underwent significant thinning after the 1040th cycle. Moreover, during accelerated degradation testing, the electrochemical surface area decreased and was therefore found to be the main factor affecting the performance decay of the MEA. Copyright © 2010 John Wiley & Sons, Ltd.     

Identification and evaluation of antioxidants defatted Camellia oleifera seeds by isopropanol salting-out pretreatment

Seven flavonoid glycosides (1–7) and one theasaponin (8) were isolated from the defatted Camellia oleifera seeds using the isopropanol salting-out pretreatment (ISP) technique, followed by column chromatography. Among them, compounds 5, 7, and 8 are new compounds. The comparison of oxygen radical absorbance capacity (ORAC) of crude extracts extracted by the n-butanol partition (BP) with those extracted by the ISP showed that the latter method yields eight times greater scavenging capacities than that of the former approach. Besides, ISP exhibited almost twice the extraction efficiency than that of BP. ORAC and Trolox equivalent antioxidant capacity (TEAC) analysis revealed that the most potent antioxidants are compounds 1 and 2, which exhibited 1.78 and 1.41 times higher antioxidant activity than that of Trolox, respectively. These results indicated that the ISP approach improves the extraction efficiency in the isolation of potent antioxidants, making the defatted C. oleifera seeds valuable in the food additive industry.     

Generalized syntheses of nanocrystal-graphene hybrids in high-boiling-point organic solvents

Nanocrystal-graphene have been proposed as a new kind of promising hybrid for a wide range of application areas including catalysts, electronics, sensors, biomedicine, and energy storage, etc. Although a variety of methods have been developed for the preparation of hybrids, a facile and general synthetic approach is still highly required. In this study, nanocrystal-graphene hybrids were successfully synthesized in high-boiling-point organic solvents. Graphene oxide (GO) nanosheets were modified by oleylamine (OLA) to form a OLA-GO complex in order to be readily incorporated into hydrophobic synthesis. A rich library of highly crystalline nanocrystals, with types including noble metal, metal oxide, magnetic material and semiconductor were successfully grown on chemically converted graphene (CCG), which is simultaneously reduced from GO during the synthesis. High boiling-point solvents afford sufficient thermal energy to assure the high-quality crystalline nature of NCs, therefore the post-annealing process is obviated. Controlled experiments revealed that OLA-GO triggers heterogeneous nucleation and serves as excellent nuclei anchorage media. The protocol developed here brings one step closer to achieve "unity in diversity" on the preparation of nanocrystal-graphene hybrids.     

Ultra-low Pt loading for proton exchange membrane fuel cells by catalyst coating technique with ultrasonic spray coating machine

This paper reports use of an ultrasonic spray for producing ultra-low Pt load membrane electrode assemblies (MEAs) with the catalyst coated membrane (CCM) fabrication technique. Anode Pt loading optimization and rough cathode Pt loading were investigated in the first stage of this research. Accurate cathode Pt coating with catalyst ink using the ultrasonic spray method was investigated in the second stage. It was found that 0.272 mg_Pt/cm² showed the best observed performance for a 33 wt% Nafion CCM when it was ultrasonically spray coated with SGL 24BC, a Sigracet manufactured gas diffusion layer (GDL). Two different loadings (0.232 and 0.155 mg_Pt/cm²) exposed to 600 mA/cm² showed cathode power mass densities of 1.69 and 2.36 W/mg_Pt, respectively. This paper presents impressive cathode mass power density and high fuel cell performance using air as the oxidant and operated at ambient pressure.     

Development of Fuel Economy Gear Oil Technology

Vehicle fuel economy will continue to increase in importance as world vehicle production grows and fuel supplies become more limited year by year. As OEMs strive to produce cars and trucks with greater fuel efficiency and extended durability, additive technology developers are increasingly being asked to contribute to these goals from the lubricant side. Axle inefficiency can account for as much as 10% of the overall losses in an automotive driveline so improvements in axle efficiency can contribute greatly to improving vehicle fuel economy. For good durability, low axle oil operating temperatures are also needed to minimize oxidative and thermal degradation of the oil, reduce deposits and sludge formation, and extend oil drain intervals. To develop gear oils that can increase axle efficiency significantly while maintaining stable operating temperatures requires rig tests that are fast, precise and reproducible. This paper documents the development of a new axle test rig and test procedures and presents test results on several gear oils. The test results show the contributions of base oil viscosity, base oil chemistry, and additive chemistry on the fuel economy and temperature of the various oils. Having a dependable tool is enabling the development of new fuel-efficient and durable gear oil technology.     

3-甲基-6-叔丁基苯酚的合成

以3-甲基苯酚、异丁烯为原料,酚铝为催化剂进行烷基化反应制备了3-甲基-6-叔丁基苯酚。较佳合成工艺条件为:催化剂的制备温度130℃,催化剂的用量为1.0%(重量比),反应温度135℃,反应时间3 h,收率达83.5%以上,同时进行了稳定性实验。     

Interfacial reactions of Sn–58Bi and Sn–0.7Cu lead-free solders with Alloy 42 substrate

Eutectic Sn–58 wt%Bi (SB) and Sn–0.7 wt%Cu (SC) lead-free solders reacting with Alloy 42 substrates were investigated at 240, 270, 300, and 330 °C for various reaction times. The FeSn₂ phase was the only phase formed at the solder/Alloy 42 interface for all couples. However, this FeSn₂ phase had two different microstructures. The intermetallic compound (IMC) morphology near the solder/Alloy 42 interface was dense with a tiny microstructure after reflowing at 240 °C. Massive spalling FeSn₂ phases with large and platy grain were observed in the solder matrix. When the reflow temperature was increased the IMC morphology assumed bulk or cylindrical shape with no spalling IMCs observed at the solder/Alloy 42 interface. The IMC thickness increased with increasing reaction temperature and time. Both SB/Alloy 42 and SC/Alloy 42 couples presented a diffusion controlled growth mechanism in. The activation energies for SB/Alloy 42 and SC/Alloy 42 couples were 86.2 and 103.4 kJ/mol, respectively.     

Changes in conformation and in sulfhydryl groups of actomyosin of tilapia (Orechromis niloticus) on hydrostatic pressure treatment

Actomyosin extracted from tilapia muscle was subjected to hydrostatic pressure treatment (50–300 MPa, 10–60 min, 4 °C) to investigate the changes in sulfhydryl groups and on conformation. Transmission electron microscopy showed that the structure of actomyosin was aggregated and disrupted above 100 MPa, and more regular network aggregates were observed as pressure increased. Moreover, pressurisation at 50 MPa for 10 min did not change actomyosin structures. Using SDS–PAGE analysis, molecules larger than the myosin heavy chain were observed when actomyosin was treated at and above 200 MPa. Below 200 MPa actomyosin formed aggregates, mainly with hydrogen bonds. Surface sulfhydryl group content of actomyosin increased with increased pressure, up to 250 MPa. However, total sulfhydryl group content of actomyosin decreased with increased pressure and time. According to this study, 200 MPa would be the critical pressure that induced actomyosin to form regular network structures.     

一次萃取钼蓝法测定锡青铜,黄铜,电解铜中的磷

在酸性溶液中用正丁醇、三氯甲烷混合液一次萃取后，以氯化亚锡还原成磷钼蓝进行比色测定。该法的表观摩尔吸光系数为２．２×１０４Ｌ·ｍｏｌ－１·ｃｍ－１，在０￣２５μｇ／２５ｍｌ范围内符合比尔定律，对锡青铜、黄铜、电解铜中磷含量在０．０００ｘ～０．３５％的试样分析结果满意，共存杂质元素不干扰磷的测定。