Employing mutually injection-locked FP LDs scheme over full-duplex radio-on-fiber transport systems

A full-duplex radio-on-fiber (ROF) transport system based on mutually injection-locked Fabry-Perot laser diodes (FP LDs) as light source is proposed and demonstrated. Transmission performances over a 40-km standard single-mode fiber (SMF) for full-duplex transmission were investigated. Good performance of bit error rate (BER) was achieved in our proposed systems. We directly modulate the FP LDs in mutually injection-locked scheme instead of using expensive external modulator and sophisticated optical carrier suppression technique; it reveals an outstanding alternative with advantages in simplicity and cost.     

Simultaneous determination of myo-inositol and scyllo-inositol by MEKC as a rapid monitoring tool for inositol levels

A simple and rapid MEKC method was developed for the simultaneous determination of myo-inositol, scyllo-inositol, and glucose. Prior to electrophoretic separation, the nonfluorescent inositols and glucose were derivatized by N-methylisatoic anhydride at 25 degrees C for 10 min so that they could be detected by a fluorescence detector during separation. The good separation with high efficiency by MEKC was achieved in 13 min with a glycine buffer containing SDS and PEG 4000. Several parameters affecting the separation were studied, including the pH of BGE, the concentrations of glycine, SDS, and PEG 4000, and the applied voltage. Using glycerol as an internal standard, the linear ranges of the method for myo-inositol, scyllo-inositol, and glucose were 0.03-10, 0.01-5, and 0.05-20 mM; the concentration LODs of myo-inositol, scyllo-inositol, and glucose were 0.020, 0.0078, and 0.026 mM, respectively. The method was applied to analyze extracellular myo-inositol and glucose in the microdialysates from rat brain cortex of ischemia animal model and intracellular myo-inositol and scyllo-inositol in the rat brain extract.     

A simple and efficient one-pot synthesis of 1,4-dihydropyridines using heterogeneous catalyst under solvent-free conditions

One-pot condensation of β-dicarbonyl compounds with aldehydes and ammonium acetate in the presence of HClO₄–SiO₂ at 80 °C under solvent-free conditions with good to excellent yields. The catalyst is easily prepared, stable, reusable and efficiently used under reaction conditions.     

Pseudoguaianolides from the Flowers of Parthenium hysterophorus

Two new pseudoguaianolide‐type sesquiterpene lactones, named deacetyltetraneurin A ( 3 ) and hysterone E ( 4 ), were isolated from flowers of the plant Parthenium hysterophorus L., along with the seven known compounds parthenin ( 1 ), coronopilin, tetraneurin A, 8‐β‐hydroxycoronopilin, scopoletin, hysterone D, and conchasin A ( 2 ). The structures of all the compounds were deduced by means of elemental analysis and extensive spectroscopic (1D and 2D NMR) studies, and confirmed for 3 and 4 by X‐ray crystallographic analysis.     

A study of the excited state structure and vibrations of hydroquinone by ab initio calculations and resonant two-photon ionization spectroscopy

Hydroquinone (HYQ) in the lowest electronically excited state has been studied by ab initio quantum chemical calculations and resonant two-photon ionization (R2PI) spectroscopy. Calculations at the MP2/6-31G* and CIS/6-31G* levels yield satisfactory results on structures and vibrational frequencies of the cis-HYQ and trans-HYQ in both the S₀ and S₁ states. Only transitions involving in-plane modes are observed in the R2PI spectrum of HYQ. All spectral bands including some newly observed ones have been successfully assigned with the help of our computed results and analogy with the reported spectra for similar molecules.     

Stable shell structures in hydrogen-bonded complexes

Neutral clusters (NH₃) _n ((CH₃)₃N) _m and (H₂O) _n ((CH₃)₃N) _m , prepared in a pulsed nozzle supersonic expansion, are ionized by multiphoton ionization and investigated with a reflectron time-of-flight mass spectrometry technique. The observed mixed cluster ions display a maximum intensity atm=2(n+1) whenn ≦ 5 for (NH₃) _n ·((CH₃)₃N) _m H⁺ andm=n+2 whenn ≦ 4 for (H₂O) _n ((CH₃)₃N) _m H⁺ indicating that the cluster ions with these combinations have a stable closed shell structure. However, the pattern begins to break down whenn>5 for ammonia system andn>4 for water system. Thereupon, the most intense peaks are reached with one molecule less than the pattern required, i.e.m=2(n+1)?1 whenn=6 for (NH₃) _n ((CH₃)₃N) _m H⁺ andm=(n+2)?1 whenn=5 for (H₂O) _n ((CH₃)₃N) _m H⁺. These findings strongly suggest the onset of hydrogen-bonded ring structures from chain-like ones at critical cluster sizes. This is also supported by the studies of the metastable decomposition.     

CATV/ROF transport systems based on light injection/optoelectronic feedback techniques and photonic crystal fiber

A directly modulated CATV/radio-on-fiber (ROF) transport system based on light injection and optoelectronic feedback techniques, and photonic crystal fiber (PCF) is proposed and demonstrated. Excellent performances of carrier-to-noise ratio (CNR), composite second order (CSO) and composite triple beat (CTB) were obtained for CATV band; as well as low bit error rate (BER) and third order intermodulation distortion to carrier ratio (IMD₃/C) values were achieved for ROF band. This demonstrated that such a CATV/ROF transport system is very attractive for the fiber backbone applications.     

Revised DEMATEL: Resolving the Infeasibility of DEMATEL

Decision Making Trial and Evaluation Laboratory (DEMATEL) has been applied in many situations, such as marketing strategies, control systems, safety problems, developing the competencies of global managers and group decision making. It has been incorporated into other methods such as Analytical Network Process (ANP), Multiple Criteria Decision Making (MCDM), fuzzy set theory, etc., to vitalize these traditional methods and explore new applications for the hybrid methods. DEMATEL models the influences of components of a system with an initial direct relation matrix. Influences of components can ripple transitively to other components, which is modeled by raising the initial direct relation matrix to powers. The total influence is computed by summing up matrices of all powers based on the assumption that the matrix raising to the power of infinity would converge to zero. The current paper shows that raising the initial relation matrix to the power of infinity may not converge to zero and hence total influence may not converge. The current paper also shows that our revised DEMATEL guarantees that the initial direct-relation matrix to infinite power will converge to zero and the total influence can be obtained accordingly. The newly developed approach is illustrated with numerical examples.     

The separation of selenium from sea water by adsorption colloid flotation

Adsorption colloid flotation can be applied successfully to the separation of selenium as SeO₃^2- from sea water. Separation is achieved in 5 min. The modified catalytic method of West and Ramakrishna is used to determine the selenium. The recovery of selenium based on spiked sea-water samples is 100 ± 10%. Standard addition analysis of near-shore Oahu sea water showed a value of 0.40 ± 0.12 μg l^-1.     

Cyclodextrin‐modified capillary electrophoresis for achiral and chiral separation of ergostane and lanostane compounds extracted from the fruiting body of Antrodia camphorata

A CD‐modified capillary electrophoretic method has been developed for achiral and chiral analysis of seven bioactive compounds isolated from the fruiting body of Antrodia camphorata. Such important target analytes exhibit similar chemical structures and are known for their diverse properties including antioxidant and anticancer effects. The analytes were separated in 25 min using a pH 9.3, 20 mM sodium borate buffer containing 20 mM methyl‐β‐CD and 30 mM sulfobutylether‐β‐CD. With the exception of the optical isomer pairs (antcin B or zhankuic acid A, zhankuic acid C, and antcin A), the remaining bioactive compounds including the chiral pair antcin C were baseline‐separated. Analysis time was noticeably longer to baseline separate all of the above chiral pairs (～38 min) by adding 5% DMF to the running buffer. The migration order was reversed compared with the HPLC elution. More hydrophobic compounds complexed favorably with methyl‐β‐CD and emerged earlier in the electropherogram than their more hydrophilic counterparts which were strongly associated with sulfobutylether‐β‐CD. The simple capillary electrophoretic method developed was applicable for rapid separation and characterization of several important bioactive compounds isolated from the fruiting body of A. camphorata.