A quantitative analysis of a trace amount of hydrogen in high temperature heat-treated carbons

A technique to determine a trace amount of hydrogen in carbon materials heat-treated above 1000 °C was developed. Three types of carbons prepared from poly(furfulyl alcohol), poly(vinyl chloride) and mesophase carbon microbeads were heat-treated at various temperatures ranging from 1000 to 1800 °C. Then they were gasified by O₂ in a fixed bed flow reactor, and the H₂O gases formed during the gasification processes were carefully monitored with a Karl Fischer moisture analyzer. As a result, this method makes it possible to determine the hydrogen contents in the carbons down to three places of decimals as a weight percent and can detect even a trace amount of hydrogen as low as 0.002 wt.%. A possible chemical structure of carbon edge sites was also discussed based on the experimentally determined hydrogen contents.     

Service-oriented mobility management architecture for seamless handover in ubiquitous networks

In ubiquitous wireless LANs, a mobile node is likely to move between many access points while using certain applications. However, in the conventional Internet architecture, an MN can never inherently avoid the degradation in communication quality during handover. To achieve seamless handover, we propose a service-oriented mobility management scheme to address application quality. In this article, we first clarify three requirements for achieving seamless handover. We then describe our concept of the service-oriented mobility management scheme, which satisfies all three requirements. Our main contribution is the proposal of a scheme of how to properly use the number of frame retransmissions as a new handover-decision criterion to accomplish seamless handover. Performance evaluations show that our proposed scheme can maintain application quality during handover     

Incorporation of Dust Particles into a Growing Film During Silicon Dioxide Deposition from a TEOS/O2 Plasma

The effects of gas flow rate on particle formation and film deposition during the preparation of silica thin film using a TEOS/O₂ plasma were investigated. Particle formation and growth are suppressed with increasing gas flow rates. The film deposition rate increases with increasing gas flow rate, reaches a maximum value, and eventually decreases again. However, the uniformity of the film tends to degrade at high gas flow rates. At a high gas flow rate, some particles trapped in the sheath near the grounded electrode pass through the sheath to reach the substrate and are then embedded in the growing film. A self-consistent sheath model combined with particle force balance based on charge fluctuation was developed to explain these experimental findings qualitatively. The model reveals that charge fluctuation is a key factor for the particle to overcome the potential barrier of the negatively charged particles to pass through the sheath, eventually reaching the substrate. The model further shows that the probability of a particle being deposited on the substrate is higher for increased gas flow rates, which correctly predicts the experimentally observed trend.     

Noninsulin-dependent diabetes mellitus-related encephalopathy presenting with amnesia, personality change, and autonomic seizure

OBJECTIVE: To determine the knowledge of rubella immune status among practicing obstetrician-gynecologists in the United States and of rubella immunity policies covering healthcare workers in the obstetric-care office setting. DESIGN: Mailed survey questionnaire, August through December 1994. SETTING: Physicians from multiple-practice sites including private office, public institution, university or teaching hospital, and closed panel health maintenance organization settings. PARTICIPANTS: 3,302 practicing obstetrician-gynecologists, chosen by a systematic random sample from the AMA national physician database. MAIN OUTCOME MEASURES: Participants were defined as rubella immune if they reported knowledge of prior rubella vaccination or positive antibody titer. Knowledge of a policy for documenting rubella immunity among employees in the office-based practice setting also was assessed. RESULTS: Questionnaires were returned from 50% (1,666) of the 3,302 surveyed, and 96% (1,599) were evaluable. Approximately 20% (304/1,599) of the responding obstetrician-gynecologists did not have knowledge of documented rubella immunity, and the majority of office-based practices did not require documentation of rubella immunity in the following groups: physicians, 66% (723/1,094); office nurses, 62% (666/1,070); and other office staff, 69% (728/1,063). Sixty-two percent (993/1,599) of responding physicians had individual rubella serologies performed, with 916 known to be positive, 53 reported negative, and 24 reported unknown. Fifty-seven percent (918/1,599) reported receiving monovalent rubella vaccine or trivalent measles-mumps-rubella vaccine. Multiple logistic regression analysis revealed the following to be independent predictors of positive immune status among respondents: female gender (odds ratio [OR], 2.4; 95% confidence interval [CI95], 1.8-3.1), medical school graduation since 1980 (OR, 2.6; CI95, 2.0-3.3), providing obstetric or fertility services (OR, 1.5; CI95, 1.2-1.9), and group practice setting (> or = 5 physicians; OR, 1.2; CI95, 1.1-1.4). CONCLUSIONS: Nationally, nearly one of every five practicing obstetricians may not have documented rubella immunity, and the majority of office-based practices have no system for assuring such immunity. Rubella immunity should extend beyond the hospital setting, with consideration for requiring rubella immunity as a condition for employment. Methods for effective implementation and documentation of current guidelines need to be addressed, particularly in the office setting.     

Magnesia porous particle separators for lithium-aluminum/iron sulfide batteries

Magnesium oxide porous particles (～200 μm) made by sintering a fine powder of MgO with Mg(NO₃)₂ as the binder, have been evaluated as the s     

Reversible pitch perception deficit due to carbamazepine

Carbamazepine (CBZ) is a drug frequently used to treat variety of neurological diseases or symptoms. Among its adverse effects, auditory disturbance is described rarely. In the present report, we describe an 18-year-old girl who noted false lowering of perceived pitch after starting CBZ treatment for epilepsy, and review the literature reporting CBZ-associated abnormal pitch perception.     

A study on cubic boron nitride (CBN) milling of hardened cast iron for productive and quality manufacturing of machine tool structural components

To improve efficiency and cost performance of cast iron machine tool component fabrication, an alternative process must be developed in order to replace the grinding process, which often causes a bottleneck in production. As an alternative manufacturing approach, this research applies cubic boron nitride (CBN) hard milling operations to eliminate the grinding process in order to improve the overall manufacturing process. A variety of hardened cast iron materials with Al and Mg additives and CBN tool types were prepared and tested based on a design of experimentation (DOE) to observe their effect on surface quality and tool life. Al and Mg were added to raw cast iron to achieve generation of oxide layers at the cutting edge during milling to protect the tool from wear. By executing the DOE, the optimal cutting conditions for achieving the best surface quality were introduced. Also, additional machinability tests were conducted with the optimal conditions in order to evaluate tool wear characteristics and surface quality of the machined workpieces. Based on the observation of the used tool by electron probe micro-analyzer (EPMA), a protective oxide layer of additives was observed at the cutting edge. Hardened cast iron with Al and Mg additives is found to show preferable wear and surface quality characteristics.     

船用柴油机NOx等有害排放气体的评价及处理研究--燃料喷射系统对乳化燃料在船用柴油机上使用的影响及脱硝装置的适用性

对原试验用柴油机的燃料喷射系统进行了改造。改造后的燃料喷射系统不仅可降低 NOx 的排放 ,而且使高加水率乳化燃料的使用成为可能。但另一方面 ,在低负荷时 ,使用乳化燃料不但不能获得预期的降低 NOx 排放效果 ,反而使其它有害排放增加。所以 ,也对降低 NOx 排放方法之一的脱硝装置进行了探讨 ,对其在船用柴油机上的适用性进行了试验 ,并获得了较好的效果