Deorthogonalization of ODS-CDMA QPSK by AM/PM Nonlinearity

When using a conventional demodulator, a sufficient condition to maintain ODS-CDMA codeword orthogonality is constant relative channel amplitude over the codeword duration. When transmitted over a memoryless, AM/PM nonlinearity channel, the chip-to-chip fluctuating amplitude of a composite ODS-CDMA QPSK waveform produces a chip-to-chip fluctuating phase that deorthogonalizes the ODS-CDMA codewords, resulting in an additional multiple access self-interference similar to that found in asynchronous DS-CDMA. For ODS-CDMA QPSK in an AM/PM nonlinearity channel, we utilize the Central Limit Theorem, derive, and evaluate: (i) an expression for the signal-to-distortion ratio at the demodulator output, (ii) an expression for the uncoded bit error probability, and (iii) an upper bound on the convolutionally-coded bit error probability. We find that the degradation to BER depends on both the AM/PM nonlinearity slope and the ODS-CDMA channel loading.     

Technology of thermally sprayed anilox rolls: State of art,problems, and perspectives

This paper deals with the surfacing technology of ceramic anilox rolls. The rolls are used in the printing industry to transport the precisely determined quantity of ink in the flexographic printing machines. The technology of roll surfacing is discussed by taking the following aspects into account: preparation of the powder to spray the ceramic coating; thermal spraying of the duplex (bond coating and ceramic top coating); postspray finishing by grinding and polishing; and laser engraving. The powder used as the top coating of the aniloxes is chromium oxide. This powder might be prepared by such techniques as agglomeration, fusing, and crushing, etc. The preparation technique influences coating properties, such as microstructure (tested with SEM, OM, XRD, and XPS), open porosity, microhardness, and modulus of elasticity. Comparison of these properties enables optimum powder preparation techniques to be found. APS technique is used to coat the anilox rolls. Optimization of the plasma spraying parameters is discussed. Aniloxes are submitted to the grinding and polishing of the ceramic coating before laser engraving occurs. The final roughness of the finished coating is discussed in view of an optimum absorption of the laser light energy at engraving. Possible ways of reducing the spraying time are discussed, and future research toward improving the anilox roll quality is proposed.     

Miniaturized ceramic differential scanning calorimeter with integrated oven and crucible in LTCC technology

A miniaturized ceramic differential scanning calorimeter (MC-DSC) with integrated oven and crucible is presented. Despite its small size of only 11 mm × 39 mm × 1.5 mm, all functions of a conventional DSC apparatus are integrated in this novel device - including the oven. The MC-DSC is fully manufactured in thick-film and green glass ceramic tape-based low temperature co-fired ceramics (LTCC) technology. Therefore, production costs are considered to be low. Initial results using indium as a sample material show a good dynamic performance of the MC-DSC. Full width at half maximum of the melting peak is 2.4 °C (sample mass approx. 11 mg, heating rate approx. 50 °C/min). Repeatability of the indium melting point is within ±0.02 °C. The melting peak area increases linearly with the sample mass up to at least 26 mg. Simulations of a strongly simplified finite element model of the MC-DSC are in a good agreement with measurement results allowing a model-based prediction of its basic characteristics.     

Tomato Sterol 22-desaturase Gene CYP710A11: Its Roles in Meloidogyne incognita Infection and Plant Stigmasterol Alteration

Sterols are isoprenoid-derived lipids that play essential structural and functional roles in eukaryotic cells. Plants produce a complex mixture of sterols, and changes in plant sterol profiles have been linked to plant–pathogen interactions. β-Sitosterol and stigmasterol, in particular, have been associated with plant defense. As nematodes have lost the ability to synthesize sterols de novo, they require sterols from the host. Tomato (Solanum lycopersicum) plants infected by the plant parasitic nematode Meloidogyne incognita show a reduced level of stigmasterol and a repression of the gene CYP710A11, encoding the sterol C-22 desaturase that is responsible for the conversion of β-sitosterol to stigmasterol. In this study, we investigated the role of the tomato sterol C-22 desaturase gene CYP710A11 in the response to infection by M. incognita. We explored the plant–nematode interaction over time by analyzing the plant sterol composition and CYP710A11 gene regulation in S. lycopersicum after M. incognita infection. The temporal gene expression analysis showed that 3 days after inoculation with M. incognita, the CYP710A11 expression was significantly suppressed in the tomato roots, while a significant decrease in the stigmasterol content was observed after 14 days. A cyp710a11 knockout mutant tomato line lacking stigmasterol was analyzed to better understand the role of CYP710A11 in nematode development. M. incognita grown in the mutant line showed reduced egg mass counts, presumably due to the impaired growth of the mutant. However, the nematodes developed as well as they did in the wild-type line. Thus, while the suppression of CYP710A11 expression during nematode development may be a defense response of the plant against the nematode, the lack of stigmasterol did not seem to affect the nematode. This study contributes to the understanding of the role of stigmasterol in the interaction between M. incognita and tomato plants and shows that the sterol C-22 desaturase is not essential for the success of M. incognita.     

用动态剪切模量估算NR与SBR硫化胶的化学交联密度

用美国Ｍｏｎｓａｎｔｏ公司的橡胶加工过程分析仪测定ＮＲ和ＳＢＲ硫化胶或混炼胶料的动态剪切模量（Ｇ＇），进而根据Ｇ＿Ｎ￣０＝ｇ×２Ｘ＿０ＲＴ和Ｇｅ＝ｇ＇×２Ｘ＿（ｐｈ）ＲＴ估算其硫化胶的化学交联密度（Ｘ＿ｃｈ），结果发现：ＮＲ／过氧化二异丙苯体系硫化胶和混炼胶料的Ｇ＇是不同的，但用Ｇ＇估算的Ｘ＿ｃｈ与用化学分析法测定的结果基本相近；对ＳＢＲ／促进剂ＴＭＴＤ体系，用这种方法估算的Ｘ＿（ｃｈ）接近用应力－应变法和ＮＭＲ法的估算值；对ＮＲ／促进剂ＴＭＴＭ体系，用Ｇ＇估算的Ｘ＿（ｃｈ）与用溶胀法获得的数据基本接近。用Ｇ＇估算Ｘ＿（ｃｈ）法，十分简单、方便。     

Precision poly-(dimethyl siloxane) masking technology for high-resolution powder blasting

Powder blasting micro-erosion is a fast and flexible technique for the micropatterning of brittle materials. We have combined 10 /spl mu/m diameter Al/sub 2/O/sub 3/ eroding particles with a new masking technique to realize the smallest possible structures with the powder blasting process (30 /spl mu/m). Our masking technology is based on the sequential combination of two polymers: 1) the brittle epoxy resin SU8 for its photosensitivity and 2) the elastic and thermo-curable poly-(dimethyl siloxane) (PDMS) for its large erosion resistance. We have micropatterned glass microstructures with aspect ratio 1 and structural details down to 20 /spl mu/m. We compare the mask size-dependent etching rate using both 1.0 and 30 jam diameter Al/sub 2/O/sub 3/ particles and find a decreasing etching rate for structures that are smaller than about 10 times the particle size. Combining SU8 with PDMS proves to be a very easy and accurate masking technology that allows exploring the fundamental dimensional limits of the powder blasting micro-erosion process.     

Fabrication of a multichannel wavelength-division multiplexing-passive optical net demultiplexer with arrayed-waveguide gratings and diffractive optical elements

A novel, to our knowledge, integrated wavelength-division multiplexing-passive optical net demultiplexer that uses an arrayed-waveguide grating and diffractive optical elements is presented. The demultiplexer is used to distribute 1.3-mum wavelength signals and to multiplex an eight-channel wavelength-division multiplexer spectrum at a 1.55-mum wavelength. The device shows high functionality and good optical performance. The measured cross talk was less than -21 dB, and the 3-dB bandwidth was determined to be 97 GHz, which is close to the theoretical value of 93 GHz. Average losses of 4.5 and 8 dB were measured for the 1.3- and the 1.55-mum signals, respectively.     

Transgenic DNA integrated into the oat genome is frequently interspersed by host DNA

Integration of transgenic DNA into the plant genome was investigated in 13 transgenic oat (Avena sativa L.) lines produced using microprojectile bombardment with one or two cotransformed plasmids. In all transformation events, the transgenic DNA integrated into the plant genome consisted of intact transgene copies that were accompanied by multiple, rearranged, and/or truncated transgene fragments. All fragments of transgenic DNA cosegregated, indicating that they were integrated at single gene loci. Analysis of the structure of the transgenic loci indicated that the transgenic DNA was interspersed by the host genomic DNA. The number of insertions of transgenic DNA within the transgene loci varied from 2 to 12 among the 13 lines. Restriction endonucleases that do not cleave the introduced plasmids produced restriction fragments ranging from 3.6 to about 60 kb in length hybridizing to a probe comprising the introduced plasmids. Although the size of the interspersing host DNA within the transgene locus is unknown, the sizes of the transgene-hybridizing restriction fragments indicated that the entire transgene locus must be at least from 35-280 kb. The observation that all transgenic lines analyzed exhibited genomic interspersion of multiple clustered transgenes suggests a predominating integration mechanism. We propose that transgene integration at multiple clustered DNA replication forks could account for the observed interspersion of transgenic DNA with host genomic DNA within transgenic loci.