Two furano-sesquiterpenes from the South China Sea Sponge Dysidea fragilis

A new sesquiterpene, ent-furodysin (1), has been isolated from the South China Sea Sponge Dysidea fragilis, along with a known sesqui-terpene, ent-furodysinin (2). The structure and relative stereochemistry of 1 and 2 were established by spectral analysis.     

Two new bioactive sesquiterpenes from the soft coral Sinularia sp

Two new sesquiterpenes, 1S*, 4R*, 5S*, 6R*, 7S*, 10S*-1(5), 6(7)-diepoxy-4-guaiol (1) and 1S*, 4S*, 5S*, 10R*-4,10-guaianediol (2) have been isolated from the ethyl acetate soluble portion of the soft coral Sinularia sp., and their stereostructure were determined by spectroscopic methods and by X-ray single crystal analysis. Both compounds showed antioxidant and cytotoxic activities.     

海绵Rhaphisia pallida的化学成分研究(I)──两种结构罕见的十元杂环化合物的结构测定

从海绵RhaphisiaPallida中分离到2个白色晶体,经综合运用波谱方法测定出它们的结构,是2个十分罕见的具有二酰亚胺基和脲基的十元杂环新化合物.     

Tighter Constraints of Multiqubit Entanglement

Monogamy and polygamy relations characterize the distributions of entanglement in multipartite systems.We provide classes of monogamy and polygamy inequalities of multiqubit entanglement in terms of concurrence, entanglement of formation, negativity, Tsallis-q entanglement, and Rényi-α entanglement, respectively. We show that these inequalities are tighter than the existing ones for some classes of quantum states.     

海绵Polymastia Sobustia的化学成分研究

首次报道从中国南海海绵Polymas tia sobustia中分离得到5个纯化合物,经过MS,IR,1H NMR,13C NMR (DEPT),HMQC和HMBC等波谱技术鉴定为：豆甾-5-烯-7-羰基-3β-甾醇(1 ),N-(1-羟甲基-2,6-二羟基)十七烷基-5-羟基二十四脂肪酰胺([ ST5”HZ 2),胸腺嘧啶(3),尿嘧啶(4[ ST5”BZ ),对羟基苯甲酸(5);其中化合物1和化合 物2为新化合物。     

海绵Phyllospongia sp.中两个新的Scalarane型二倍半萜

海绵Ｐｈｙｌｌｏｓｐｏｎｇｉａｓｐ．中两个新的Ｓｃａｌａｒａｎｅ型二倍半萜万一千，苏镜娱，曾陇梅，王明焱（中山大学化学系，广州，５１０２７５）关键词海绵，二倍半萜，分离，结构鉴定Ｐｈｙｌｌｏｓｐｏｎｇｉａ属含有丰富二倍半萜的海绵体［１～７］，从这种海...     

南海短足软珊瑚Cladiella sp.的化学成分

神经酰胺;烷醇孕甾酮;南海短足软珊瑚Cladiella sp.的化学成分     

2D NMR对Sarcophine所有^1H NMR和^1^3C NMR归属的指定

从中国南海软珊瑚Sarcophyton molle中分离得到大环二萜内酯Sarcophine(1)。本文利用^1H-^1H COSY，HMQC，HMBC等二维谱手段首次对Sarcophine所有^1H NMR、^1^3C NMR的信号归属进行了完全的指定。并第一次报道了其^1^3C NMR数据。     

Amending Coherence-Breaking Channels via Unitary Operations

The coherence-breaking channels play a significant role in quantum information theory. We study the coherence-breaking channels and give a method to amend the coherence-breaking channels by applying unitary operations. For given incoherent channel Φ, we give necessary and sufficient conditions for the channel to be a coherence-breaking channel and amend it via unitary operations. For qubit incoherent channels Φ that are not coherence-breaking ones, we consider the mapping Φ °Φ and present the conditions for coherence-breaking and channel amendment as well.     

Tighter Weighted Polygamy Inequalities of Multipartite Entanglement in Arbitrary-Dimensional Quantum Systems

We investigate polygamy relations of multipartite entanglement in arbitrary-dimensional quantum systems. By improving an inequality and using the βth (0 ≤ β ≤ 1) power of entanglement of assistance, we provide a new class of weighted polygamy inequalities of multipartite entanglement in arbitrary-dimensional quantum systems. We show that these new polygamy relations are tighter than the ones given in Kim (Phys. Rev. A 97, 042332 2018).