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  • Springer  (261)
  • Cambridge University Press
  • 1990-1994  (262)
  • 1950-1954  (4)
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Year
  • 11
    Electronic Resource
    Electronic Resource
    Low resistance and large current range CW single-mode top surface-emitting laser with small window (1993)
    Springer
    Optical and quantum electronics 25 (1993), S. 745-749 
    Details
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract We report the results of a room-temperature CW top surface-emitting laser whose light-emitting window is much smaller than the current injection area. The lowest series resistance of device is 50 Ω. It maintains single transverse mode at high current levels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00430563
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  • 12
    Electronic Resource
    Electronic Resource
    Novel hybrid construction of a visible surface-emitting laser and its two-dimensional arrays (1993)
    Springer
    Optical and quantum electronics 25 (1993), S. 467-472 
    Details
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract A novel hybrid surface-emitting laser and two-dimensional laser array is reported. The device consists of rectangular GaAs reflectors and edge-emitting single laser or one-dimensional laser arrays which are fabricated separately. The devices are mounted upside-down on a copper heat sink, allowing for good heat conduction. The CW operation and the reflectivity characteristics of this surface-emitting laser have been investigated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00421744
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  • 13
    Electronic Resource
    Electronic Resource
    A novel structure of visible semiconductor lasers (1990)
    Springer
    Optical and quantum electronics 22 (1990), S. 385-389 
    Details
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract Terraced substrate inner current stripe lasers emitting in the range of 750–780 nm are developed with very simple fabrication processes. The lasers have good performance of cw room temperature, linear light-current output over 30 mW per facet and maintain stable fundamental transverse and longitudinal mode of 2–4 times current threshold. The current threshold of 25 mA under cw room temperature operation has been achieved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02189221
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  • 14
    Electronic Resource
    Electronic Resource
    Crystal structure of lanthanum(III) oxalate decahydrate (1991)
    Springer
    Journal of chemical crystallography 21 (1991), S. 127-131 
    Details
    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract La2(C2O4)3·10H2O crystallizes in space groupP21/c (No. 14) witha=11.382(6),b=9.624(5),c=10.502(8) Å,β=114.52(4)°, andZ=2. The structure (R=0.029 for 3190 MoKα data) is composed of two-dimensional networks of edge-sharing 1∶5∶3 coordination polyhedra matching the (020) set of planes, each La(III) atom being surrounded by threeη 4 chelating oxalate groups and three aqua ligands with La-O distances in the range 2.518(4)–2.622(4) Å. The remaining water molecules are disordered over seven principal sites in the intervening space.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01161053
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  • 15
    Electronic Resource
    Electronic Resource
    Syntheses, crystal structures, and characterizations of two novel cubane-like and double cubane-like molybdenum-copper-sulphur clusters {MoCu3S3(S2COEt)}(O)(Ph3P)3 and {Mo2Cu6S6(SCMe3)2}(O)2(Ph3P)4 (1992)
    Springer
    Journal of cluster science 3 (1992), S. 201-218 
    Details
    ISSN: 1572-8862
    Keywords: Cubane-like ; double cubane-like ; Molybdenum-copper-sulphur clusters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Two novel heterometallic cubane-like and double cubane-like clusters, {MoCu3S3(S2COEt)}(O)(Ph3P)3 I and {Mo2Cu6S6(SCMe3)2}(O)2(Ph3P)4 II, were synthesized by reaction of {MoCu2S3}(O)(Ph3P)3 with CuS2COEt and CuSCMe3, respectively. ClusterI crystallized in the triclinic space group $$P\overline 1 $$ (2) witha=12.766(6) Å,b=22.904(5) Å,c=10.522(3) Å, α=99.86(2)°, β=109.68(2)°, γ=86.84(3)°,V=2854(2) Å3,Z=2,R=0.049 for 6622 observed reflections (I〉5σ(I)) and 410 variables. ClusterII crystallized in the triclinic space group $$P\overline 1 $$ (2) with dimensionsa=14.212(4) Å,b=14.725(5) Å,c=12.396(8) Å, α=110.32(4)°, β=90.40(5)°, γ=62.88(2)°,V=2129(2) Å3,Z=1,R=0.039 for 6020 observed reflections (I〉3σ(I)) and 461 variables. ClusterI consists of a neutral cubane-like molecule with the core {MoCu3S3(S2COEt)}2+, in which one corner of the cubane-like core is a novel triply bridging bidentate 1,1-dithiolato (xanthate, S2COEt−) ligand. ClusterII is a double cubane-like one, in which two cubane-like cores {MoCu3S3(SCMe3)}2+ are connected by two Cu-S bonds of the triply bridging monothiolato (SCMe 3 − ) ligand. Two different pathways of unit construction from a small heterometallic cluster {MoCu2S3}(O)(Ph3P)3 have been outlined. Comparisons of the selected bond lengths and bond angles for the cubane-like core {MoCu3S3 X} (X=Cl−, Br−, S2COEt−, SCMe 3 − ) are given. Spectroscopic properties of the title clusters are also reported.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00702883
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  • 16
    Electronic Resource
    Electronic Resource
    The designed synthesis and crystallographic characterization of three novel heterotrimetallic linear complexes of [Et4N][(Ph3P)2{M′S2 MS2Fe}Cl2] (M=Mo,M′=Ag;M=W,M′=Cu, Ag) (1993)
    Springer
    Journal of cluster science 4 (1993), S. 89-103 
    Details
    ISSN: 1572-8862
    Keywords: Designed synthesis ; heterotrimetallic ; linear complexes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The complexes [Et4N][(Ph3P)2{M′S2 MS2Fe}Cl2] (M=Mo,M′=Ag;M=W,M′=Cu, Ag) have been obtained by reaction of [Et4N]2[S2 MS2FeCl2] (M=Mo, W) with Cu(PPh3)3Cl or Ag(PPh3)3NO3 in MeCN/CH2Cl2, respectively. Crystal data for [Et4N][(PPh3)2 {AgS2MoS2Fe}Cl2] (I): triclinic, P $$\bar 1$$ (No. 2),Z=2,a=13.41(1)Å,b=15.54(1)Å,c=12.30(1)Å, α=105.24(6)°, β=94.63(7)°, γ=101.38(6)°, andV=2399(4)Å3. The bond lengths of Mo-Fe bond and the Mo-Ag distance are 2.756(2)Å and 3.033(2)Å, respectively. Crystal data for [Et4N][(PPh3)2 {AgS2WS2Fe}Cl2] (II): triclinic, P $$\bar 1$$ (No. 2),Z=2,a=13.457(5))Å,b=15.601(6)Å,c=12.338(4)Å, α=105.20(3)°, β=94.61(4)°, γ=101.43(4)°, andV=2426(2)Å3. The bond length of W-Fe bond and the W-Ag distance are 2.786(2)Å and 3.076(1)Å, respectively. Crystal data for [Et4N][(PPh3)2 {CuS2WS2Fe}Cl2] (III): triclinic, P $$\bar 1$$ (No. 2),Z=2,a=13.498(5)Å,b=15.372(4)Å,c=12.340(4)Å, α=105.54(2)°, β=93.32(3)°, γ=101.40(3)°, andV=2401(1)Å3. The bond lengths of W-Fe bond and the W-Cu bond are 2.800(1)Å and 2.851(1)Å, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00702711
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  • 17
    Electronic Resource
    Electronic Resource
    Designed synthesis for some transition metal clusters involving bridging-sulfido ligand (1994)
    Springer
    Journal of cluster science 5 (1994), S. 265-285 
    Details
    ISSN: 1572-8862
    Keywords: Designed synthesis ; transition metal clusters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Designed synthesis for some transition metal clusters involving bridging-sulfido ligands is reviewed. The basic concept with the use of reactive fragments as building blocks is described. It is shown that the sulfido ligands with lone-pair electrons and the unsaturated coordination sites play important roles in this rational synthesis. The relationship between the metallic coordination types of the sulfido ligands and their assembling activity in the compounds is summarized. Examples of the six kinds of “unit construction” with reactive fragments as building blocks are shown, indicating clearly that the “unit construction” is a reasonable way in the synthesis of transition metal clusters involving bridging sulfido ligands. Finally, the potential application of the “unit construction” schemes in the synthesis of transition metal clusters involving other bridging ligands is presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01170712
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  • 18
    Electronic Resource
    Electronic Resource
    On steiner ratio conjectures (1991)
    Springer
    Annals of operations research 33 (1991), S. 437-449 
    Details
    ISSN: 1572-9338
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Economics
    Notes: Abstract LetM be a metric space andP a finite set of points inM. The Steiner ratio inM is defined to beρ(M)=inf{L s(P)/L m(P) |P ⊂M}, whereL s(P) andL m(P) are the lengths of the Steiner minimal tree and the minimal spanning tree onP, respectively. In this paper, we study various conjectures onρ(M). In particular, we show that forn-dimensional Euclidean spaceℝ n ,ρ(ℝ n )〉0.615.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02071981
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  • 19
    Electronic Resource
    Electronic Resource
    On Rosen's gradient projection methods (1990)
    Springer
    Annals of operations research 24 (1990), S. 9-28 
    Details
    ISSN: 1572-9338
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Economics
    Notes: Abstract This paper is a survey of Rosen's projection methods in nonlinear programming. Through the discussion of previous works, we propose some interesting questions for further research, and also present some new results about the questions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02216813
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  • 20
    Electronic Resource
    Electronic Resource
    On better heuristics for Steiner minimum trees (1992)
    Springer
    Mathematical programming 57 (1992), S. 193-202 
    Details
    ISSN: 1436-4646
    Keywords: Steiner trees ; approximation performance ratio
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract Finding a shortest network interconnecting a given set of points in a metric space is called the Steiner minimum tree problem. The Steiner ratio is the largest lower bound for the ratio between lengths of a Steiner minimum tree and a minimum spanning tree for the same set of points. In this paper, we show that in a metric space, if the Steiner ratio is less than one and finding a Steiner minimum tree for a set of size bounded by a fixed number can be performed in polynomial time, then there exists a polynomialtime heuristic for the Steiner minimum tree problem with performance ratio bigger than the Steiner ratio. It follows that in the Euclidean plane, there exists a polynomial-time heuristic for Steiner minimum trees with performance ratio bigger than $${\textstyle{1 \over 2}}\sqrt 3 $$ . This solves a long-standing open problem.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01581080
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