GaAs多结电池宽光谱ZnS/Al2O3/MgF2减反射膜的设计与分析

 为了提高砷化镓(GaAs)多结太阳电池的光电转换效率,设计了宽光谱(300 nm～1 800 nm)ZnS/Al2O3/MgF2三层减反射膜,分析了各层的厚度及折射率对三层膜系有效反射率的影响。结果表明： 对于整个波长,ZnS厚度对有效反射率的影响要大于Al2O3和MgF2,MgF2厚度对有效反射率的影响最小;适当减小MgF2的折射率或增加ZnS的折射率可得到更低的有效反射率。同时,当 ZnS,Al2O3和MgF2的最优物理厚度分别为52.77 nm,82.61 nm,125.17 nm时,此时最小有效反射率为2.31％。     

On the vanishing of the Lannes–Zarati homomorphism

The conjecture on spherical classes states that the Hopf invariant one and the Kervaire invariant one classes are the only elements in H_?(Q₀S⁰)$H_{?}(Q_0{S}^0)$ belonging to the image of the Hurewicz homomorphism. The Lannes–Zarati homomorphism is a map that corresponds to an associated graded (with a certain filtration) of the Hurewicz map. The algebraic version of the conjecture predicts that the s  -th Lannes–Zarati homomorphism vanishes in any positive stems for s>2$s>2$. In the article, we prove the conjecture for the fifth Lannes–Zarati homomorphism.     

On canonical metrics on Cartan–Hartogs domains

The Cartan–Hartogs domains are defined as a class of Hartogs type domains over irreducible bounded symmetric domains. The purpose of this paper is twofold. Firstly, for a Cartan–Hartogs domain \(\Omega ^{B^{d_0}}(\mu )\) endowed with the canonical metric \(g(\mu ),\) we obtain an explicit formula for the Bergman kernel of the weighted Hilbert space \(\mathcal {H}_{\alpha }\) of square integrable holomorphic functions on \(\left( \Omega ^{B^{d_0}}(\mu ), g(\mu )\right) \) with the weight \(\exp \{-\alpha \varphi \}\) (where \(\varphi \) is a globally defined Kähler potential for \(g(\mu )\) ) for \(\alpha >0\) , and, furthermore, we give an explicit expression of the Rawnsley’s \(\varepsilon \) -function expansion for \(\left( \Omega ^{B^{d_0}}(\mu ), g(\mu )\right) .\) Secondly, using the explicit expression of the Rawnsley’s \(\varepsilon \) -function expansion, we show that the coefficient \(a_2\) of the Rawnsley’s \(\varepsilon \) -function expansion for the Cartan–Hartogs domain \(\left( \Omega ^{B^{d_0}}(\mu ), g(\mu )\right) \) is constant on \(\Omega ^{B^{d_0}}(\mu )\) if and only if \(\left( \Omega ^{B^{d_0}}(\mu ), g(\mu )\right) \) is biholomorphically isometric to the complex hyperbolic space. So we give an affirmative answer to a conjecture raised by M. Zedda.     

Nil Bohr0-sets and polynomial recurrence

In Huang et al.  [17] it was proved that for any Nil_d  Bohr₀-set A$A$, there are a minimal system (X,T)$(X,T)$ and a non-empty open subset U$U$ of X$X$ with A⊃{n∈Z:U∩T⁻ⁿU∩?∩T^−dnU≠0?}$A\supset \{n\in \mathbb{Z}:U\cap T^{-n}U\cap ?\cap T^{-dn}U\ne 0?\}$, and for any minimal system (X,T)$(X,T)$ and any open non-empty U⊂X$U\subset X$, the set {n∈Z:U∩T⁻ⁿU∩?∩T^−dnU≠0?}$\{n\in \mathbb{Z}:U\cap T^{-n}U\cap ?\cap T^{-dn}U\ne 0?\}$ is an almost Nil_d Bohr₀-set. The polynomial form of this problem is considered in this paper. It is shown that the latter is still true in the polynomial case, while the former is not in general. We also consider the special case when the system is a nilsystem.     

Enantiorecognition ability of peptoids with α-chiral, aromatic side chains

The enantiorecognition ability of oligomeric N-substituted glycines or "peptoids" with α-chiral, aromatic side chains was investigated by HPLC and (1)H NMR studies.     

Secolignans, neolignans and phenylpropanoids from Daphne feddei and their biological activities

Two new secolignans and one new neolignan, named feddeiphenols A-C (1-3), together with eight known compounds (4-11), were isolated from the leaves and stems of Daphne feddei. Their structures were established on the base of spectroscopic methods, mainly extensive NMR, UV spectroscopy, and MS spectrometry. Compounds 1-11 were tested for their anti-human immunodeficiency virus (HIV)-1 activity and cytotoxicity. The results revealed that compounds 1, 2, 3, 7, and 9 showed therapeutic index (TI) values above 30, respectively, and the other compounds also showed weak anti-HIV-1 activity. Compound 1 showed modest cytotoxic activity. The other compounds also showed weak cytotoxic activity.     

Tuning the electronic coupling in a low-bandgap donor-acceptor copolymer via the placement of side-chains

We present a spectroscopic and theoretical investigation of the effect of the presence and position of hexyl side-chains in the novel low-bandgap alternating donor-acceptor copolymer poly[bis-N,N-(4-octylphenyl)-bis-N,N-phenyl-1,4-phenylenediamine-alt-5,5'-4',7',-di-2-thienyl-2',1',3'-benzothiadiazole] (T8TBT). We use electronic absorption and Raman spectroscopic measurements supported by calculations of chain conformation, electronic transitions, and Raman modes. Using these tools, we find that sterically demanding side-chain configurations induce twisting in the electronic acceptor unit and reduce the electronic interaction with the donor. This leads to a blue-shifted and weakened (partial) charge-transfer absorption band together with a higher photoluminescence efficiency. On the other hand, sterically relaxed side-chain configurations promote coupling between donor and acceptor units and exhibit enhanced absorption at the expense of luminescence efficiency. The possibility of tuning the donor-acceptor character of conjugated polymers by varying the placement of side-chains has very important ramifications for light emitting diode, Laser, display, and photovoltaic device optimization.     

Uncatalyzed and Solvent‐Free Process for the Synthesis of 1,4‐Diarylquinoline Derivatives

The uncatalyzed and three‐component reaction of arylaldehyde, malonodinitrile, and 3‐arylamino‐5,5‐dimethylcyclohex‐2‐enone at 160 °C under solvent‐free conditions gave 1,4‐diarylquinoline derivatives in high yields.     

Efficient One‐Pot Synthesis of 2‐Amino‐4,6‐diarylbenzene‐1,3‐dicarbonitrile under Solvent‐Free Conditions

A facile parallel synthesis of 2‐amino‐4,6‐diarylbenzene‐1,3‐dicarbonitrile derivatives via a one‐pot reaction of aromatic aldehydes, aromatic ketone, and malononitrile under solvent‐free conditions has been developed. This new protocol has the advantages of shorter time, higher yields, lower cost, and environmental friendliness.     

Efficient [4+1]/[3+2+1] bis-cyclizations stereoselectively yielding unprecedented polyacyclic indeno-fused xanthenes

Concise and efficient [4+1]/[3+2+1] bis-cyclizations of o-phthalaldehyde with cyclic 1,3-dicarbonyls have been established for the stereoselective synthesis of unprecedented polycyclic indeno[2,1-l]xanthene derivatives. The multicomponent domino reaction (MDR, AB₂ type) is easy to perform by mixing inexpensive substrates in HOAc at room temperature. The present synthesis shows attractive properties such as the simple one-pot fashion, high bond-forming efficiency, and easy purifications. Up to two new rings and four sigma-bonds were achieved in these MDRs without using any metal catalysts.