Heavy metal pollution profiles of dated sediment cores from hebe haven, Hong Kong

Eight sediment cores from Hebe Haven were collected and studied for metals including Cd, Cr, Cu, Fe, Ni, Pb, Zn and Ca. ²¹⁰Pb and ¹³⁷Cs activities were determined to date the time of deposition of the sediment. Hebe Haven is a yacht area and is close to the urbanized coast with several dyeing factories. Except Cd, the greatest enrichment was found at locations closest to the Ho Chung Stream which carried domestic and industrial wastewater to Hebe Haven. Concentrations as high as 0.930, 120, 131, 42.3 and 50.9 mg/kg were found for Cd, Cr, Zn, Cu and Pb, respectively. The corresponding enrichment factors are 13(Cd), 7.0(Cr), 2.9(Zn), 5.2(Cu) and 2.4(Pb). The extent of pollution diminishes from the riverine source. Cr is a typical example because its enrichment was mostly attributed to the nearby dyeing operation. The distribution of Cd appears more complicated. A maximum concentration of 3.60 mg/kg was found at a location far from Ho Chung Stream and with no nearby municipal or industrial activity. No significant Fe and Ni enrichment was found in the area. Ca in all cores decreases towards the sediment-water interface. It is probable that the abundance of shellfish has decreased as a result of excessive exploitation as seafood and pollution. ²¹⁰Pb activity and heavy metal concentrations of surficial layers have been “diluted” by excessive deposition of Fe-deficient particles. This likely indicates the rapid deposition of coarser and sandy particles during the construction of a nearby large housing estate. Some ²¹⁰Pb activity profiles have periodic low values in deeper layers, which should correspond to events of rapid deposition of erosion during heavy typhoons and rainstorms. Overall, the sedimentation rates calculated were in the range of 0.351–0.561 cm/yr. In one site (Core S4) close to the riverine source and with the best available dating data, the recent anthropogenic fluxes of heavy metals in μg cm⁻² yr⁻¹ are estimated as: 0.081(Cd), 22(Cr), 20(Zn), 6.4(Cu) and 7.4(Pb).     

Optical and structural properties of LaF3 thin films

LaF(3) thin films of different thicknesses were deposited on CaF(2) (111) and silicon substrates at a relatively low substrate temperature of 150 degrees C. Optical (transmittance, reflectance, refractive index, and extinction coefficient) and mechanical (morphology and crystalline structure) properties have been investigated and are discussed. It is shown that LaF(3) thin films deposited on CaF(2) (111) substrates are monocrystalline and have a bulklike dense structure. Furthermore, it is presented that low-loss LaF(3) thin films can be deposited not only by boat evaporation but also by electron beam evaporation.     

Unlocking diamond's potential as an electronic material

In this paper, we review the suitability of diamond as a semiconductor material for high-performance electronic applications. The current status of the manufacture of synthetic diamond is reviewed and assessed. In particular, we consider the quality of intrinsic material now available and the challenges in making doped structures suitable for practical devices. Two practical applications are considered in detail. First, the development of high-voltage switches capable of switching voltages in excess of 10 kV. Second, the development of diamond MESFETs for high-frequency and high-power applications. Here device data are reported showing a current density of more than 30 mA mm(-1) along with small-signal RF measurements demonstrating gigahertz operation. We conclude by considering the remaining challenges which will need to be overcome if commercially attractive diamond electronic devices are to be manufactured.     

Affect, sex guilt, gender, and the rewarding-punishing effects of erotic stimuli.

40 male and 40 female college students were classified as high or low in sex guilt (HSG and LSG, respectively) using the Mosher Forced-Choice Guilt Inventory. Experimental Ss were shown erotic slides following each "correct" choice in a discrimination task and nonerotic slides following each "incorrect" choice. Controls were shown nonerotic slides following all choices. HSG Ss made fewer choice responses leading to erotica than did LSG Ss, and females made fewer erotica-producing choices than did males. HSG and female Ss were less positive in their affective reactions to the erotica than were LSG and male Ss. Correlational and regression analyses revealed that sex guilt and gender differences in choice behaviors leading to erotica were predicted solely on individual differences in intensity of positive affective responses. Regardless of sex guilt and gender, for those high in positive affect, the erotic stimuli functioned as rewards, but for those low in positive affect, the stimuli functioned as punishers. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Kalorimetrie und Thermodynamik des Systems Eisen-Phosphor

Schrifttumsübersicht zu den energetischen Daten des Systems Eisen–Phosphor. Quantitative thermische Analyse des Zustandsdiagrammes. Bestimmung der energetischen Größen. Thermodynamische Berechnung der Zustandslinien in Konsistenz zu den experimentell ermittelten Phasengleichgewichten.     

On the Performance of a Feedback Communication System Utilizing a Cumulative Decision Scheme

A cumulative decision scheme that can be employed in a feedback communication system is treated. Any decision to decode depends upon all messages that have been received prior to the decision. The average error over all transmissions as well as the forward error may be controlled. Performance is compared to an error-detection repeat-request noncumulative scheme utilizing group codes. Optimal performance of the cumulative scheme with respect to the noncumulative scheme is given for short-length best group codes. It is also demonstrated that the use of feedback does not necessarily increase appreciably the amount of hardware necessary to effect error control.     

Erprobung eines Richtapparates mit fliegend gelagerter Biegerolle für das Richten von Stahldraht

Lagerschwierigkeiten beim schnellen Richten von dünnem, hochfestem Stahldraht mit herkömmlichen Rollenrichtapparaten. Entwicklung eines neuartigen Richtgerätes mit fliegend gelagerter Biegerolle. Aufbau und Wirkungsweise der Versuchseinrichtung. Berechnung und Messung der Rollenkräfte und der Durchziehkraft im Draht. Richtwirkung bei angetriebenen und geschleppten Stützrollen.     

Über die Konstitution der Styrololigomeren aus der thermischen Polymerisation

Saturated and unsaturated oligomers are formed by a side reaction during the thermal polymerization of styrene. MAYO has suggested that these oligomers are closely associated with the initiation step. Recently the structures of the dimer fraction were published by BROWN . By independent synthesis of the dimers we could confirm his results. The main components of the dimer fraction are trans- and cis-1.2-diphenylcyclobutane in a ratio of 3:1 ; also smaller amounts of 1.3-diphenylbutene-(3) and I-phenyltetralin were found. The aim of this work was to clarify the structures of the trimers. The trimer fraction contains about 30% of 1.3.5-triphenylhexene-(5), the structure of which was confirmed by independent synthesis. Furthermore we were able to show, that about 65% of the trimer fraction consists of the 4 optical inactive isomers of 1-phenyl-4-[1′-phenyläthyl-(1′)]-1.2.3.4.-tetrahydronaphthalene. Their structures were confirmed by dehydrogenation to 1-phenyl-4-[1′-phenyläthyl-(1′)]-naphthalene, which was identical to an independently synthesized sample.