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1.
Nie Renwang Wu Qingyong Yu Zhuqing Wang Aiguo Shen Xiaodong 《Journal of Thermal Analysis and Calorimetry》2022,147(12):6643-6654
Journal of Thermal Analysis and Calorimetry - Coral wastes are produced during the construction of island. The use of coral wastes in concrete is beneficial to economy and environment. Coral waste... 相似文献
2.
Let (v,u×c,λ)-splitting BIBD denote a (v,u×c,λ)-splitting balanced incomplete block design of order v with block size u×c and index λ. Necessary conditions for the existence of a (v,u×c,λ)-splitting BIBD are v≥uc, λ(v−1)≡0 (mod c(u−1)) and λ
v(v−1)≡0 (mod (c
2
u(u−1))). We show in this paper that the necessary conditions for the existence of a (v,3×3,λ)-splitting BIBD are also sufficient with possible exceptions when (1) (v,λ)∈{(55,1),(39,9k):k=1,2,…}, (2) λ≡0 (mod 54) and v≡0 (mod 2). We also show that there exists a (v,3×4,1)-splitting BIBD when v≡1 (mod 96). As its application, we obtain a new infinite class of optimal 4-splitting authentication codes. 相似文献
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Xiao Zhou Hongbo Huang Jie Li Yongxiang Song Renwang Jiang Jing Liu Si Zhang Yan Hua Jianhua Ju 《Tetrahedron》2014
Six cycloheptadepsipeptides, marformycins A–F (1–6), featuring a unique N-terminally formylated side chain and five non-proteinogenic amino acid residues, were isolated from the deep Sea-derived Streptomyces drozdowiczii SCSIO 10141. The previously unsolved absolute stereochemistry of 3 and 4 was determined and the structures of other four new congeners were elucidated by extensive spectroscopic, chiral-phase HPLC, and single-crystal X-ray diffraction analyses. Compounds 1–5 bear no cytotoxicity against a number of human tumor cell lines but show selective anti-infective activity against Micrococcus luteus. 相似文献
7.
A magic rectangle of size is an array consisting of consecutive integers in which the sum of each row is a constant and the sum of each column is another (different if ). It is centre-complementary if the sum of any pair of centrally symmetric positions is constant. As a natural generalization of symmetric magic squares, centre-complementary magic rectangles are instrumental in the construction of 3-dimensional rectangles. In this paper, we focus our attention on the existence of centre-complementary magic rectangles and prove that the necessary conditions for the existence of centre-complementary magic rectangles are also sufficient. 相似文献
8.
To enhance the structural diversity of tanshinones and provide more derivatives for the biological studies, a one‐pot combinatorial modification strategy was performed on total tanshinones. Six new quinoxlinetanshinones 1 – 6 were subsequently isolated from the combinatorial modified semi‐synthetic mixture. The structures were elucidated by spectroscopic analysis in combination with single‐crystal X‐ray diffraction. These quinoxlinetanshinones demonstrated strong DNA binding properties. Rapid synthesis of new quinoxlinetanshinones with significant biological activity highlights the great potential of one‐pot combinatorial modification for the diversification of natural products. 相似文献
9.
Suppose K
v
is the complete undirected graph with v vertices and K
4 − e is the graph obtained from a complete graph K
4 by removing one edge. Let (K
4 − e)-MRC(v) denote a resolvable covering of K
v
with copies of K
4 − e with the minimum possible number n(v, K
4 − e) of parallel classes. It is readily verified that n(v, K4-e) 3 é2(v-1)/5 ù{n(v, K_4-e) \geq \lceil 2(v-1)/5 \rceil} . In this article, it is proved that there exists a (K
4 − e)-MRC(v) with é2(v-1)/5 ù{\lceil 2(v-1)/5 \rceil} parallel classes if and only if v ≡ 0 (mod 4) with the possible exceptions of v = 108, 172, 228, 292, 296, 308, 412. In addition, the known results on the existence of maximum resolvable (K
4 − e)-packings are also improved. 相似文献
10.
A novel Rh(II)-catalyzed transannulation of 1-tosyl-1,2,3-triazoles with silyl or alkyl enol ethers has been developed, which enables the facile synthesis of substituted pyrroles in a regiocontrollable manner. Moreover, the methodology could be extended to access 3-pyrrolin-2-one derivatives with silyl ketene acetals used as the reaction partner. 相似文献