No abstract

Four-junction AlGaAs/GaAs laser power converters (LPCs) with n+-GaAs/p+-Al0.37Ga0.63As heterostructure tunnel junctions (TJs) have been designed and grown by metal-organic chemical vapor deposition (MOCVD) for converting the power of 808 nm lasers. A maximum conversion efficiency ηc of 56.9% ± 4% is obtained for cells with an aperture of 3.14 mm2 at an input laser power of 0.2 W, while dropping to 43.3% at 1.5 W. Measured current–voltage (I–V) characteristics indicate that the performance of the LPC can be further improved by increasing the tunneling current density of TJs and optimizing the thicknesses of sub-cells to achieve current matching in LPC.

No abstract

Ahhslmcl -A ST, 204mni wnrtn bore siipcrconducting inagnct system for HEMS-1 MHD model ship bas hcen sutccssfully devctopcd, tcstcrl nnd used for MIID lielic~l thruster devclopmciit and rnodcl ship opcration. The system iscliitlcs a 5T, high curi'cnt tlciisity, cluse-prclwl, wnx-fillctl superconrlricting solenoid with 422 LJ stored ningnetjc cncrgy, R 204inm wiirni horc, liorizoiitrl, liglitwcigl;t, low liert losses [Icwnr nnd a IKA pcrsistciit murlel opcratioii system. The total wcight of ttw wliolc system is 49dKg. The test rcsrilts show tlint the rverrge LHc cotnuniption is 0,3411trr. and the systcni call be opcrrtcrl for nboat 170 tlDllrS without LHc refilling. 'I'he paper s 11 inmrrizccl the design, dcvclopinent, cotistriiction and tcst rcsiilts o f tlic system. I n desTI PIP-MA I3 , s o h 110 id , PC S, s ti p c rc oil tl uct i n g mag net warm bore has been developed and constructed. For persistclit inodc opcration, corresponding 1 KA superconducting switch, dctachable cunnnt lcads mid diode protection system have been also dcvclopcd. TIic total weight of thc whole systcin is 494 Kg, the test results show that thc average liquid helium consumption for pcrsislciir inode operation is 0.34 I h , thc syslcin can bc opcrated as 5'1' permaneill lnagnct for about 170 hours without LHe d i l l i n g . It Culfilled all the requirements of thc MHD model ship and can be also used to conduct othcr important high tnagiictic field application cxperitnents. Table 1. listed (lie tnaiii parameters of the system. '[he papcr summarized the dcsign, developmenl, construction, test and applicatioii of this superconducting soleimid systcm.

Six-junction vertically-stacked GaAs laser power converters (LPCs) with n + -GaAs/p + -Al 0.37 Ga 0.63 As tunnel junctions have been designed and grown by metal-organic chemical vapor deposition for converting the power of 808 nm lasers. The LPC chips are characterized by measuring current-voltage (I-V) characteristics under 808 nm laser illumination, and a maximum conversion efficiency η c of 53.1% is obtained for LPCs with an aperture diameter of 2 mm at an input laser power of 0.5 W. In addition, the characteristics of the LPCs are analyzed by a standard equivalent-circuit model, and the reverse saturation current, ideality factor, series resistance and shunt resistance are extracted by fitting of the I-V curves.