A scalable and efficient key escrow model for lawful interception of IDBC‐based secure communication

Key escrowing is one of the core technologies for the lawful interception (LI) of secure communications in the wired and wireless networks. Although many previous studies on the key escrowing have been done before, they are insufficient to be deployed in practical networks due to conflicts with the LI requirements. Moreover, there is lack of consideration on the LI of ID‐based cryptosystem (IDBC)‐based secure communication because the interest of the LI was moved to the industries and IDBC has the inherent key escrowing property. However, the inherent property of IDBC cannot prevent ‘illegal’ eavesdropping of all the communications in the networks from the law enforcement agency with the ‘legally’ obtained key. Thus, we propose a new key escrow model that satisfies the requirements of LI and overcomes the potential threats of IDBC. Our contributions enable the scalable and efficient key escrowing for the LI of secure one‐way and two‐pass communication in the mobile networks. Copyright © 2010 John Wiley & Sons, Ltd.     

GaN nanorods grown on Si (111) substrates and exciton localization

We have investigated exciton localization in binary GaN nanorods using micro- and time-resolved photoluminescence measurements. The temperature dependence of the photoluminescence has been measured, and several phonon replicas have been observed at the lower energy side of the exciton bound to basal stacking faults (I ₁). By analyzing the Huang-Rhys parameters as a function of temperature, deduced from the phonon replica intensities, we have found that the excitons are strongly localized in the lower energy tails. The lifetimes of the I ₁ and I ₂ transitions were measured to be < 100 ps due to enhanced surface recombination.     

Mechanical synthesis and rapid consolidation of nanocrystalline 3Fe<Subscript>0.67</Subscript>Cr<Subscript>0.33</Subscript>-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> composite by high frequency induction heating

Nanopowders of 3Fe_0.67Cr_0.33 and Al₂O₃ were synthesized from CrO₃ and 2FeAl powders by high-energy ball milling. A highly dense nanocrystalline 3Fe_0.67Cr_0.33-Al₂O₃ composite was consolidated by a high frequency induction heated sintering (HFIHS) method within three minutes from mechanically synthesized powders of Al₂O₃ and 3Fe_0.67Cr_0.33. The average grain size and mechanical properties of the composite were investigated.     

Properties and rapid low-temperature consolidation of nanocrystalline Fe-ZrO<Subscript>2</Subscript> composite by pulsed current activated sintering

Nanopowders of Fe and ZrO₂ were synthesized from Fe₂O₃ and Zr by high-energy ball milling. The powder sizes of Fe and ZrO₂ were 70 nm and 12 nm, respectively. Highly dense nanostructured 4/3Fe-ZrO₂ composite was consolidated by a pulsed current activated sintering method within 1 minute from the mechanically synthesized powders (Fe-ZrO₂) and horizontal milled Fe₂O₃+Zr powders under the 1 GPa pressure. The grain sizes of Fe and ZrO₂ in the composite were calculated. The average hardness and fracture toughness values of nanostuctured 4/3Fe-ZrO₂ composite were investigated.     

Properties and rapid consolidation of nanocrystalline 8MoSi<Subscript>2</Subscript>-Si<Subscript>3</Subscript>N<Subscript>4</Subscript> by high frequency induction heated sintering

Nanopowders of MoSi₂ and Si₃N₄ were synthesized from Mo₂N and Si by high ball milling. Dense nanostructured 8MoSi₂-Si₃N₄ composite was consolidated by high frequency induction heated sintering (HFIHS) method within two minutes from mechanically synthesized powders of MoSi₂ and Si₃N₄. Highly dense 8MoSi₂-Si₃N₄ composite with a relative density of up to 97 % was produced under simultaneous application of 80 MPa pressure and the induced current. The average grain size and mechanical properties (hardness and fracture toughness) of the composite were investigated.     

Comparison of line edge roughness and profile angles of chemical vapor deposited amorphous carbon etched in O2/N2/Ar and H2/N2/Ar inductively coupled plasmas

In this study, we compared the line edge roughnesses (LER) and profile angles of chemical vapor deposited (CVD) amorphous carbon (a-C) patterns etched in an inductively coupled plasma (ICP) etcher produced by varying process parameters such as the N₂ gas flow ratio, Q (N₂), and dc self-bias voltage (V_dc) in O₂/N₂/Ar and H₂/N₂/Ar plasmas. The tendencies of the LER and profile angle values of the etched CVD a-C pattern were similar in both plasmas. The LER was smaller in the O₂/N₂/Ar than in the H₂/N₂/Ar plasmas, and the profile angle was larger in the O₂/N₂/Ar than in the H₂/N₂/Ar plasmas under the same processes conditions. The use of O₂/N₂/Ar plasma was more advantageous than the H₂/N₂/Ar plasma for controlling LER and profile angle.     

Chemical coupling of photocatalysis with flocculation and adsorption in the removal of organic matter

An experimental investigation was made to study the effects of chemical coupling of flocculation and adsorption with photocatalysis in treating persistent organic pollutants in wastewater. The photocatalysis alone showed initial reverse reaction when titanium oxide (TiO(2)) was used in catalysis. The effect of the pretreatment of adsorption with powdered activated carbon (PAC) on photocatalysis was studied. The results showed that PAC adsorption followed by photocatalysis was not effective in alleviating reverse reaction. On the other hand, when PAC and TiO(2) were added simultaneously, the reverse reaction was eliminated. Further, the organic removal was also improved by simultaneous PAC and TiO(2) additions. When flocculation with ferric chloride (FeCl(3)) was used as pretreatment, the organic removal efficiency was superior. The initial reverse reaction was also eliminated/minimized. However, inadequate doses of FeCl(3) (less than 30 mgl(-1)) resulted in initial reverse reaction and inferior DOC removal.