Highly stable optical add/drop multiplexer using polarization beam splitters and fiber Bragg gratings

We demonstrate a novel wavelength-division add/drop multiplexer employing fiber Bragg gratings and polarization beam splitters. The multiplexer is easy to fabricate without any special technique such as UV trimming, and yet shows very stable performance with less than 0.3-dB crosstalk power penalty in a 0.8-nm-spaced, 2.5-Gb/s-per-channel wavelength-division multiplexing (WDM) transmission system.     

Effective suppression of signal-wavelength dependent transients in a pump-controlled L-band EDFA

Typical pump-controlled L-band erbium-doped fiber amplifiers (EDFAs) in a feed-forward scheme give significant transients due to gain difference on wavelength of input signal when only a few channels are left. The fiber Bragg grating added pump-controlled L-band EDFA eliminates the wavelength dependent gain difference and transients.     

Mass transfer in liquid-fluidized and spouted beds of ion exchange resin at low Reynolds number

Rates of mass transfer from the liquid phase to small ion exchange resin particles (0.78 mm in mean diameter) in fluidized and spouted beds were studied experimentally. Dilute aqueous solution of sodium hydroxide was fed into the beds of strong cation exchange resin and the exit concentration of the solution was determined by conductivity measurement. In spouted beds, the initial conversion and K_l increased with bed height, but decreased with fluid flowrate. The model, applying material balance of the reactant and axisymmetric flow of fluid in the annulus of a spouted bed, predictions of the initial conversion in spouted beds are satisfactory. In fluidized beds, the obtained mass transfer coefficients were correlated and compared with other works.     

Influence of ZnCl2 on the structure and mechanical properties of polyacrylonitrile fibers

The structure and mechanical properties of polyacrylonitrile fibers containing small amounts of Zn²⁺ were investigated. It is possible to interpret the influence of ZnCl₂ on the fibers by diffusion. Fibers spun from spinning dope containing ZnCl₂ may have a denser and finer structure because ZnCl₂ in the spinning dope retards the coagulation rate. The tensile strength and modulus of the fibers are much improved because of the retardation of coagulation. It is probable that the complexation between Zn²⁺ and CN groups does not contribute to the improvement of the mechanical properties because the amount of ZnCl₂ added in a spinning dope is extremely small.     

The safety and efficacy of transcatheter arterial chemoembolization in the treatment of patients with hepatocellular carcinoma and main portal vein obstruction. A prospective controlled study

BACKGROUND: Transcatheter arterial chemoembolization (TACE) has been contra-indicated for the treatment of patients with hepatocellular carcinoma (HCC) and main portal vein (MPV) obstruction because of the potential risk of hepatic insufficiency resulting from ischemia after TACE. The current controlled study was undertaken to assess the safety, efficacy, and predictive factors of favorable response to TACE in patients with HCC and MPV obstruction with good hepatic function and adequate collateral circulation around the MPV. METHODS: Of a total of 47 patients, 31 were treated with TACE, and 16 who declined the procedures were untreated controls. Thirty-six patients (77%) had diffuse-type HCC and 11 (23%) had nodular-type HCC. During the first week after TACE immediate postprocedural complications were evaluated, and the development of hepatic insufficiency as a late complication was assessed at the end of the fourth week. The cumulative survival rate was estimated by the Kaplan-Meier method, and predictors of better prognosis were obtained by univariate and multivariate analyses. RESULTS: Although no patients showed clinical evidence of hepatic insufficiency as an immediate complication, transient fever and abdominal pain were common. Progressive hepatic insufficiency developed at the fourth week; however, there was no difference between the treated and untreated groups. The survival time of treated patients was statistically no longer than that of untreated patients. In the univariate analysis, tumor type and size, the pattern of iodized oil uptake in the tumor, and the presence of iodized oil uptake in the tumor thrombi at the MPV significantly influenced the prognosis. Tumor type, whether treated or not, was the most important prognostic factor patients with nodular-type HCC had significantly longer survival time (median, 11 months) than those with diffuse-type HCC (median, 4 months). Regarding the efficacy of TACE, there was no statistical difference in survival between treated and untreated diffuse-type HCC patients. In comparison, with nodular-type HCC it seemed that survival time was longer for TACE-treated patients (median, 30 months) than for untreated patients (median, 7 months). CONCLUSIONS: TACE may be a safe modality for the treatment of patients with HCC and MPV obstruction, provided that the patients have good hepatic function and collateral circulation around the MPV. However, TACE was not efficacious in the treatment of diffuse-type HCC. The authors recommend TACE for treating nodular-type HCC because of the potential benefit of prolonged survival.     

功能材料与军品包装

功能材料及其复合材料在抗静电、吸波、隐身以及其它的光、电、热、化学等通用性方面具有突出的优点，在此重点讨论几种有代表性功能材料的现状与发展?并指出它们在军品包装领域的应用前景。     

Efficacy of measles vaccine during the 1993 measles epidemic in Korea

Immunization to eliminate measles is recommended at 15 months of age with the option of giving vaccine at 6 to 9 months of age during measles outbreaks in Korea. Because of the recent resurgence of measles and concern about the possibility of reduced vaccine efficacy caused by genomic differences between vaccine virus and contemporary wild measles viruses, we conducted a measles vaccine efficacy study involving children with household exposure ages 1 to 5 years during measles outbreak that had occurred 1993 in Seoul and Seong-nam city, with the demographic analysis of patients brought to the hospitals. A total of 380 patients (M:F = 216:164) were included in this study. Two hundred nine cases (55.0%) occurred in children less than 5 years of age, and 167 (43.9%) were younger than 16 months of age. The recorded age-specific incidence rates showed bimodal patterns, i.e. highest peak in those below 16 months of age and second peak in those ages 6 to 9 years of age. Only 9.6% (16 of 167) of the measles cases less than 16 months, 59.5% (25 of 42) of those 16 months to 4 years and 91.8% (157 of 171) of the cases in school age children have been vaccinated. Attack rates among the 122 vaccinated siblings and 12 unvaccinated siblings ages 1 to 5 years who contacted measles were 5.7 and 75%, respectively, and the clinical vaccine efficacy was 92.4% (95% confidence interval, 83.6, 96.4). The high vaccine efficacy in household exposures suggests that measles outbreaks in Korea are not caused by reduced vaccine efficacy.     

Effect of Brazilin on Plasma Lipid Levels in Spontaneously Hypertensive Rats

The levels of plasma lipid and lipoprotein in spontaneous hypertensive male rats (SHR) fed on normal chow diet, SHR fed on normal chow diet containing 2% cholesterol plus 10% olive oil and SHR fed on the same fat rich diet with the administration (100 mg/kg, orally) of brazilin, 7,11b-Dihydrobenz [b] indeno 1,2-d) pyran-3,6a,9,10 [6H]-tetrol, were determined to elucidate the effects of brazilin on the improvement of abnormalities in plasma lipid and lipoprotein concentrations of essential hypertensive rats. Plasma levels of total cholesterol, triglyceride and high density lipoprotein-cholesterol of SHR were significantly changed toward normal physiological values by the treatment with brazilin.