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121.
BACKGROUND: Phytase is increasingly used as an ingredient in swine and poultry feeds to improve the bioavailability of phytate‐bound phosphorus and reduce the supplement of elemental phosphorus in feeds. Recently, a transgenic rise (TGR) with phytase appA gene from E. coli has been developed in Taiwan. To assure the food safety of this TGR, we performed a sub‐chronic whole‐food feeding study with Wistar rats. RESULTS: Weaned feeding male and female rats were divided into TGR and non‐TGR (NTGR) groups (20 rats per group), and fed diets containing 76.8% rice flour of TGR and NTGR, respectively. After 93 days feeding, although some hematological findings and blood chemistry values differed significantly between the TGR and NTGR groups, all values were still within the normal range for rats of this age and sex. No adverse effects of TGR were observed in terms of animal behavior, weight gain, or feed utilization rate. Necropsy at the end of the experiment indicated that neither pathological lesions nor histopathological abnormalities were present in organs such as liver, kidney, intestines and testes of rats in TGR and NTGR groups. In addition, no significant differences (P > 0.05) were observed in relative organ weights, hemograms and blood indices of rats between the two groups. CONCLUSION: These results demonstrated that in a 93‐day feeding study with Wistar rats a diet containing 76.8% of TGR flour having a phytase activity of about 1500 U kg?1 body weight per day has no adverse effects. Copyright © 2007 Society of Chemical Industry  相似文献   
122.
L-band radiometer brightness temperature measurements of a saltwater pond were made as a function of salinity and temperature. A precision L-band radiometer with stability better than 0.1 K per day was used for these measurements. The L-band measurements are in good agreement with three dielectric constant models over a temperature range from 8/spl deg/C to 32/spl deg/C and a salinity range from 25-40 psu. Based on this experiment, these dielectric models will provide an excellent basis for the algorithm development and design of the future National Aeronautics and Space Administration Aquarius satellite mission.  相似文献   
123.
Cross-layer QoS Analysis of Opportunistic OFDM-TDMA and OFDMA Networks   总被引:1,自引:0,他引:1  
Performance analysis of multiuser orthogonal frequency division multiplexing (OFDM-TDMA) and orthogonal frequency division multiple access (OFDMA) networks in support of multimedia transmission is conducted in this work. We take a cross-layer approach and analyze several quality-of-service (QoS) measures that incilude the bit rate and the bit error rate (BER) in the physical layer, and packet average throughput/delay and packet maximum delay in the link layer. The authors adopt a cross-layer QoS framework similar to that in IEEE 802.16, where service classification, flow control and opportunistic scheduling with different subcarrier/bit allocation schemes are implemented. In the analysis, the Rayleigh fading channel in the link layer is modeled by a finite-state Markov chain, and the channel state information (CSI) is assumed to be available at the base station. With the M/G/1 queueing model and flow control results, the analysis provides important insights into the performance difference of these two multiaccess systems. The derived analytical results are verified by extensive computer simulation. It is demonstrated by analysis and simulation that OFDMA outperforms OFDM-TDMA in QoS metrics of interest. Thus, OFDMA has higher potential than OFDM-TDMA in supporting multimedia services.  相似文献   
124.
We develop a simple analytical model of an ideal duobinary generating low-pass filter. The model provides important physical insight into the design of optically amplified duobinary systems. We verify the theory with experimental data at 10 Gb/s.  相似文献   
125.
A liquid crystal display can be described as a panel consisting of two plates of glass with liquid crystals in the space between. Generally, the liquid crystal wastes are extracted and separated into various fractions. Some recyclable materials, i.e., metals, glass, plastics, etc., are recycled, but the liquid crystals are incinerated. The emission factors for 16 U.S. EPA priority polycyclic aromatic hydrocarbons (PAHs) from the combustion of liquid crystal are approximately 390 and 1520 times higher than that of waste terephthalic acid and biological sludge combustion, respectively. In this study, we determined the emission of PAHs from the liquid crystals pyrolysis. We also investigated the fragments and gas compositions using on-line thermogravimetry–mass spectrometry (TG–MS). A temperature series of 14 fragments was analyzed in nitrogen, and was found to include m/z: 30, 32, 42, 44, 55, 57, 67, 81, 95, 109, 128, 166, 178, and 202. The fragments at m/z 32 represents formaldehyde and the fragment at m/z 44 is carbon dioxide. The fragments at m/z 55, 57, 67, 81, 95, and 109 represent hydrocarbon components, all of which may be liquid crystal by products. The TG–MS as analyzed above can offer a better understanding of the mechanisms of byproduct formation in liquid crystal waste pyrolysis.Experimentally, not detected (n.d.) −5.98 and n.d. −20.2 μg/g of 16 PAHs, in the particulate and gas phases, respectively, are determined from the emission of liquid crystal waste pyrolysis. The PAH profiles showed a predominance of naphthalene (42.6%) and phenanthrene (13.5%). The total PAH emissions for the 16 species were 7.75 and 44.05 μg/g in the particulate and gas phases, respectively, significantly lower than the values associated with liquid crystal combustion. From the viewpoint of PAH emission control, our results suggest that the pyrolysis is a better option for the disposal of liquid crystal wastes than that of combustion.  相似文献   
126.
Antioxidant activity, malolactic fermentation and sensory evaluation of the grape must after fermentation in the presence of gallic acid and coumaric acid, as well as the inhibitory mechanism of gallic acid and coumaric acid on pectin methyl esterase (PME), were investigated. The content of malic acid and lactic acid increased 40.4% and 36.9% compared to the control when commercial pectic enzyme (CPE) was used. The increase in malic acid content was enhanced by 64.8% and 83.4%, compared to the control in the presence of CPE + Gallic acid and CPE + Coumaric acid respectively. Ferric reducing/antioxidant power (FRAP) increased in the samples with added CPE. In addition to an increase in the FRAP, antioxidant capacity was enhanced in the CPE + Gallic acid and CPE + Coumaric acid samples. No significant differences were found in the content of total anthocyanin and in the value of sensory characteristics. The content of total flavanols increased significantly in the samples with added CPE. Lineweaver‐Burk plots of PME, with gallic acid or coumaric acid, indicated that gallic acid and coumaric acid were mixed inhibitors of PME.  相似文献   
127.
128.
In this investigation, we propose and experimentally demonstrate the remodulation technique using DPSK format in both downlink and uplink traffics with high extinction ratio (ER) in colorless WDM-PON; together with a simple self-restored architecture against fiber fault. Error free operation was achieved in a 20-km-reach 10-Gb/s WDM-PON without dispersion compensation. Comparison with other wavelength remodulation schemes for WDM-PONs is also performed, showing the proposed scheme can be a potential candidate for next generation wavelength reuse WDM-PONs. In addition, the performance of self-protection has also been discussed and analyzed.  相似文献   
129.
During the recent years, the major driving forces of customer preference, vehicle safety, environmental protection, and flat demand for new cars led to a proliferation of car models and associated price reduction in the auto supply chain. To react to the complex and competitive environment, auto suppliers are urgent to conduct continual improvement (CI) in an effective and systematic way. Thus, this paper presents a framework for CI. The Integrated Development System is proposed to integrate both capability maturity model integration and six‐sigma approach. By implementing the framework, an automaker can establish a solid process‐based management system, identify critical processes, and optimize these processes. For demonstrating the application of this framework, a case study is presented and the result shows that all expected processes' performance targets are achieved, which has dramatically improved by 70% compared with the past records. Apparently, the proposed framework would act as a useful reference to improve an organization's process maturity. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
130.
Highly efficient blue electrophosphorescent organic light‐emitting diodes incorporating a bipolar host, 2,7‐bis(diphenylphosphoryl)‐9‐[4‐(N,N‐diphenylamino)phenyl]‐9‐phenylfluorene (POAPF), doped with a conventional blue triplet emitter, iridium(III) bis[(4,6‐difluoro‐phenyl)pyridinato‐N,C]picolinate (FIrpic) are fabricated. The molecular architecture of POAPF features an electron‐donating (p‐type) triphenylamine group and an electron‐accepting (n‐type) 2,7‐bis(diphenyl‐phosphoryl)fluorene segment linked through the sp3‐hybridized C9 position of the fluorene unit. The lack of conjugation between these p‐ and n‐type groups endows POAPF with a triplet energy gap (ET) of 2.75 eV, which is sufficiently high to confine the triplet excitons on the blue‐emitting guest. In addition, the built‐in bipolar functionality facilitates both electron and hole injection. As a result, a POAPF‐based device doped with 7 wt% FIrpic exhibits a very low turn‐on voltage (2.5 V) and high electroluminescence efficiencies (20.6% and 36.7 lm W?1). Even at the practical brightnesses of 100 and 1000 cd m?2, the efficiencies remain high (20.2%/33.8 lm W?1 and 18.8%/24.3 lm W?1, respectively), making POAPF a promising material for use in low‐power‐consumption devices for next‐generation flat‐panel displays and light sources.  相似文献   
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