CHARACTERIZATION OF SELENIUM CATALYST FOR COAL LIQUEFACTION IN TERMS OF HYDROGENATION AND CRACKING ABILITY

ABSTRACT

The activities of selenium and zinc chloride catalysts upon transferable hydrogen in coal have been investigated by ^IH-NMR. Se is more active than ZnCl₂ for hydrogen transfer in the coal/anthracene system. The change of radical concentration was monitored by high temperature ESR. It was confirmed that radical concentration in the coal/Se system is greater than that in the coal/ZnCl₂ system at the early stage of pyrolysis. It was concluded that Se has a higher cracking activity as well as hydrogen transfer ability and there is the potential for the use of Se as a catalyst for coal liquefaction.     

Permanent magnet synchronous motors using primarily reluctance torque

Permanent magnet synchronous motors (PMSMs) are widely used in many applications as high‐performance variable‐speed drives. In traction drives, such as those used for electric vehicles or for the compressor drives of air conditioners, a wide constant‐power speed range and high‐efficiency operation are desired. The aim of this paper is to develop a high‐performance PMSM that offers high‐efficiency performance in the high‐speed region, including light‐load conditions, as well as a wide constant‐power speed range. Simulations show that the proposed interior PMSM, which produces chiefly reluctance torque and in which the permanent magnet flux assists torque production, is capable of meeting the above performance requirements. A prototype PMSM is designed in accordance with this new design concept and several drive tests are carried out. The saliency ratio of the prototype IPMSM is about 5, and, as a result, reluctance torque is the principal torque component, representing more than 70% of total torque. The prototype IPMSM can attain a constant‐power speed range of up to 5:1 with high‐efficiency drive in the high‐speed, constant‐power region. The proposed IPMSM is suitable for variable‐speed drives requiring high‐speed, constant‐power operation. © 2000 Scripta Technica, Electr Eng Jpn, 134(3): 60–68, 2001     

Assessment of postoperative digestive function after pancreatico-duodenectomy: a comparison of reconstruction techniques

BACKGROUND/AIMS: Malabsorption is a frequent complication following pancreatico-duodenectomy (PD) for pancreatic carcinoma. Gastrojejunostomy followed by Billroth I type of reconstruction (PD III) has been advanced to prevent this disorder. We compared postoperative digestion and absorption determined by 131I-triolein, D-xylose and pancreatic function diagnostant (PFD) after extensive PD followed by one of two reconstructive procedures. MATERIAL AND METHODS: Postoperative digestive and absorptive functions in patients operated by Child's method (PD II) were compared with patients in whom the stomach emptied proximal to the pancreas and bile duct (PD III). RESULTS: The absorption of D-xylose was significantly higher (1.24 +/- 0.36 g vs. 0.72 +/- 0.21 g) in the PD III group. No difference was noted in pancreatic endocrine secretion between the two groups. Biliary scintigraphy revealed increased bile secretion in the PD III group. CONCLUSIONS: These results suggest that PD III is superior to PD II following extensive PD.     

Distributed-index planar microlens array prepared from deep electromigration

Monolithic fabrication of a new distributed index planar microlens array by means of a deep electromigration technique in a glass substrate is reported. The array consists of distributed index lenses of 1.2 mm in diameter with 6.8 mm focal length. The focused spot is as small as 16 ?m for ?=0.63 ?m. The coupling efficiency of 60% to a multimode VAD fibre has been obtained.     

Optoelectronic integrated four-channel transmitter arrayincorporating AlGaAs/GaAs quantum-well lasers

A four-channel optoelectronic integrated transmitter array which is fabricated on a single GaAs substrate and operates at 834 nm is described. Each of the circuits incorporates a laser, a photodiode for laser power monitoring, and a laser driver circuit consisting of three GaAs field-effect transistors and a resistor. Laser threshold current of 15-21 mA, transmitter conversion efficiency of approximately 6 mW/V and high-speed operation at a bit rate of more than 1.5-Gb/s NRZ with allowable crosstalk have been demonstrated. A preliminary aging test of the lasers indicated that their stability is comparable to that of discrete devices. The results have demonstrated the feasibility of applying the transmitter array to optical components that process multichannel optical signals at high speed     

A co-channel interference cancellation technique using orthogonalconvolutional codes on multipath Rayleigh fading channel

This paper proposes and evaluates a new co-channel interference cancellation technique that utilizes orthogonal convolutional codes on a multipath Raleigh fading channel. In a spread spectrum multiple access environment co-channel interference (CCI) limits the performance of the communication link. To remove this interference, several CCI cancellation techniques have been proposed, including a technique that does not require the receiver to have knowledge of the cross-correlation between user sequences. This method leaves residual interference after the cancellation caused by errors in the initial decisions. To reduce the residual interference and improve the initial decisions, the proposed scheme utilizes the error-correcting capability of orthogonal convolutional codes. This paper evaluates the performance of this scheme. Our results show that the proposed CCI canceller offers an improvement in capacity of a factor of 1.5~3 as compared with a conventional canceller on a multipath Rayleigh fading channel. The proposed canceller works in the presence of residual interference due to imperfect cancellation. The proposed canceller also has a capacity improvement with the use of soft handoff in a multicell configuration     

Purification and properties of alpha-amino-beta-carboxymuconate-epsilon-semialdehyde decarboxylase (ACMSD), key enzyme of niacin synthesis from tryptophan, from hog kidney

alpha-Amino-beta-carboxymuconate-epsilon-semialdehyde decarboxylase (ACMSD) (EC 4.1.1.45) was purified to a homogeneous state from hog kidney cytosol by ammonium sulfate fractionation, Butyl-Toyopearl 650, hydroxyapatite, DEAE-Sephadex, Toyopearl HW55, Superdex 200 and TSK-gel G3000SW chromatographies. The molecular weight of the enzyme was estimated to be 58,000 by TSK-gel G3000SW gel filtration. The optimum pH (constant concentration) was 7.5. The Km for alpha-amino-beta-carboxymuconate-epsilon-semialdehyde was 1.61 x 10(-5) M. The activity of purified enzyme was inhibited by some chemical modifying reagents such as monoiodoacetic acid and p-(chloromercuri) benzoic acid. A sulfhydryl group was deduced to exist in the active site of the enzyme.     

Antioxidant activity of ferulic acid beta-glucuronide in the LDL oxidation system

Antioxidant activity of ferulic acid beta-glucuronide, which is prepared from the plasma of feruloyl arabinose fed rats, in the CuSO4- induced LDL autoxidation system was studied. It has been found that absorbed ferulic acid occurred as the beta-glucuronide and that the antioxidant activity of ferulic acid beta-glucuronide, which has not only the hydrophobic ferulic acid moiety but also a hydrophilic sugar moiety, is stronger than ferulic acid in the LDL oxidation system.     

High-speed monolithic coherent optical receiver integrated on InP substrate

A monolithic coherent receiver have a directional waveguide coupler and a balanced pair of lateral pin photodiodes was fabricated. The lateral pin photodiode has an improved structure, exhibiting a 3 dB bandwidth of 2 GHz. Heterodyne detection with this monolithic receiver was demonstrated at 1.8 GHz and 2.3 GHz.<>