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1.
Imran Sadiq Shahzad Naseem Saira Riaz S. Sajjad Hussain Muhammad Naeem Ashiq Mazhar Rana 《自然科学进展(英文版)》2018,28(4):478-482
Rare earth Dy~(3+)and divalent Mn~(2+)elements substituting W-type hexagonal ferrites Ba_(1-x)Dy_xZn_2Fe_(16-y)Mn_yO_(27)(x=0,0.02,0.06,0.1 and y=0,0.1,0.3,0.5)were prepared by sol-gel method.The thermo-gravimetric analysis(TGA)and differential scanning calorimetry(DSC)was carried out to find the temperature at which single phase can be obtained.XRD patterns indicate the presence of the single phase for all the synthesized samples with the absence of any extra peak due to unreacted material and secondary phases.The occurrence of absorption bands at low wave numbers(563 and 446 cm~(-1)),can be assigned to the stretching vibration of metal and oxygen ions in FTIR spectra,which also confirms the single hexagonal phase for prepared material.The grains are of platelet like structure,which enhances the microwave absorption properties of hexagonal ferrites.The synthesized material exhibits the minimum reflection loss of-20.9 dB at 11.8 GHz frequency,which reflects the applications of this material in super high frequency devices.The microwave conductivity of the material increases with frequency. 相似文献
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Shalik Ram Sigdel Jayram Pandey Eryuan Liang Sher Muhammad Flurin Babst Steven W.Leavitt Miaogen Shen Haifeng Zhu Franco Salerno Shilong Piao J.Julio Camarero Josep Peuelas 《科学通报(英文版)》2021,(18):1825-1829
Global temperature has been increasing at unprecedented rates during the Anthropocene,impacting both natural and human sys-tems [1].Alpine biomes,among the most... 相似文献
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In recent years, graphene has attracted considerable research interest in all fields of science due to its unique properties. Its excellent mechanical properties lead it to be used in nano-composites for strength enhancement. This paper reports an Aluminum–Graphene Nanoplatelets(Al/GNPs)composite using a semi-powder method followed by hot extrusion. The effect of GNP nano-particle integration on tensile, compressive and hardness response of Al is investigated in this paper. It is demonstrated that 0.3 wt% Graphene Nanoplatelets distributed homogeneously in the matrix aluminum act as an effective reinforcing filler to prevent deformation. Compared to monolithic aluminum(in tension), Al–0.3 wt% GNPs composite exhibited higher 0.2% yield strength(+14.7%), ultimate tensile strength(+11.1%) and lower failure strain( -40.6%). Surprisingly, compared to monolithic Al(in compression), Al–0.3 wt% GNPs composite exhibited same 0.2% compressive yield strength and lower ultimate compression strength(- 7.8%),and lower failure strain(- 20.2%). The Al–0.3 wt% GNPs composite exhibited higher Vickers hardness compared to monolithic aluminum(+11.8%).Scanning electron microscopy(SEM), Energy-Dispersive X-ray Spectroscopy(EDS) and X-ray diffraction(XRD) were used to investigate the surface morphology, elemental percentage composition, and phase analysis, respectively. 相似文献
4.
A total of 18 spider mite species belonging to 10 genera of the family Tetranychidae (Acari: Prostigmata) are reported from different provinces of Saudi Arabia (SA). Among these, two new species, Sonotetranychus madinahensis sp. nov. and Tetranychus salicornicus sp. nov., belonging to the subfamily Tetranychinae are described and illustrated. Also, five genera and 11 species are new to the mite fauna of SA. The distribution and host data of all recorded species in the current study are provided. A key to all spider mite species of SA is provided as well as a key to the species of the armenychus species group of the genus Tetranychus Dufour, based on males.
www.zoobank.org/urn:lsid:zoobank.org:pub:C41BB3ED-99D5-4DCF-B557-09526FA7D56B 相似文献
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ALI Muhammad 《东华大学学报(英文版)》2021,(2):118-128
In order to increase the application area of nanofibers, electrospun nanofiber yarns have drawn attention of many researchers around the globe. Once the production method of nanofiber yarn is mature enough to be universally accepted, many new gates of applications will open to the world. In this review, different electrospinning techniques of electrospun nanofiber yarns are divided into needle electrospinning and needleless electrospinning. Considering yarn twist as an important mechanism, needle electrospinning technique is further categorized into mechanical, electrical and field flow twisting methods. Moreover, parameters influencing the mechanical properties of electrospun nanofiber yarns are investigated. Methods of improving mechanical properties of nanofiber yarns are addressed, including hot-water-bath treatment, addition of carbon nanotubes(CNTs) and introducing regulators. Finally, applications of electrospun nanofiber yarns in different fields of smart textile and bioengineering are summed-up. In summary, challenges encountered in the industrialization of nanofiber yarns and future prospects are anticipated. 相似文献
6.
Christoph Lipps Muhammad Badar Milada Butueva Tatyana Dubich Vivek Vikram Singh Sophie Rau Axel Weber Michael Kracht Mario Köster Tobias May Thomas F. Schulz Hansjörg Hauser Dagmar Wirth 《Cellular and molecular life sciences : CMLS》2017,74(7):1319-1333
Homeostasis of solid tissue is characterized by a low proliferative activity of differentiated cells while special conditions like tissue damage induce regeneration and proliferation. For some cell types it has been shown that various tissue-specific functions are missing in the proliferating state, raising the possibility that their proliferation is not compatible with a fully differentiated state. While endothelial cells are important players in regenerating tissue as well as in the vascularization of tumors, the impact of proliferation on their features remains elusive. To examine cell features in dependence of proliferation, we established human endothelial cell lines in which proliferation is tightly controlled by a doxycycline-dependent, synthetic regulatory unit. We observed that uptake of macromolecules and establishment of cell–cell contacts was more pronounced in the growth-arrested state. Tube-like structures were formed in vitro in both proliferating and non-proliferating conditions. However, functional vessel formation upon transplantation into immune-compromised mice was restricted to the proliferative state. Kaposi’s sarcoma-associated herpes virus (KSHV) infection resulted in reduced expression of endothelial markers. Upon transplantation of infected cells, drastic differences were observed: proliferation arrested cells acquired a high migratory activity while the proliferating counterparts established a tumor-like phenotype, similar to Kaposi Sarcoma lesions. The study gives evidence that proliferation governs endothelial functions. This suggests that several endothelial functions are differentially expressed during angiogenesis. Moreover, since proliferation defines the functional properties of cells upon infection with KSHV, this process crucially affects the fate of virus-infected cells. 相似文献
7.
The Pristionchus pacificus genome provides a unique perspective on nematode lifestyle and parasitism
Dieterich C Clifton SW Schuster LN Chinwalla A Delehaunty K Dinkelacker I Fulton L Fulton R Godfrey J Minx P Mitreva M Roeseler W Tian H Witte H Yang SP Wilson RK Sommer RJ 《Nature genetics》2008,40(10):1193-1198
Here we present a draft genome sequence of the nematode Pristionchus pacificus, a species that is associated with beetles and is used as a model system in evolutionary biology. With 169 Mb and 23,500 predicted protein-coding genes, the P. pacificus genome is larger than those of Caenorhabditis elegans and the human parasite Brugia malayi. Compared to C. elegans, the P. pacificus genome has more genes encoding cytochrome P450 enzymes, glucosyltransferases, sulfotransferases and ABC transporters, many of which were experimentally validated. The P. pacificus genome contains genes encoding cellulase and diapausin, and cellulase activity is found in P. pacificus secretions, indicating that cellulases can be found in nematodes beyond plant parasites. The relatively higher number of detoxification and degradation enzymes in P. pacificus is consistent with its necromenic lifestyle and might represent a preadaptation for parasitism. Thus, comparative genomics analysis of three ecologically distinct nematodes offers a unique opportunity to investigate the association between genome structure and lifestyle. 相似文献
8.
Cells and cell-free solutions of the culture filtrate of the bacterial symbiont, Xenorhabdus nematophila taken from the entomopathogenic nematode Steinernema carpocapsae in aqueous broth suspensions were lethal to larvae of the diamondback moth Plutella xylostella. Their application on leaves of Chinese cabbage indicated that the cells can penetrate into the insects in the absence of the nematode vector. Cell-free solutions containing metabolites were also proved as effective as bacterial cells suspension. The application of aqueous suspensions of cells of X.nematophila or solutions containing its toxic metabolites to the leaves represents a possible new strategy for controlling insect pests on foliage. 相似文献
9.
SHAHID Muhammad Qasim 《科学通报(英文版)》2010,55(13):1255-1262
Oryza rufipogon exhibits abundant genetic diversity and contains many elite genes. In this work, a total of 441 accessions of O. rufipogon were genetically examined using the functional marker S5n, revealing that 18 accessions carried the S5n allele with a heterozygous genotype (S5nS5i/j). Of these accessions, 14 were from Guangdong Province, 2 from Guangxi Zhuang Autonomous Region, 1 from Hainan Province and 1 from Jiangxi Province. Further sequence analysis spanning both sides of the deletion in S5n allel... 相似文献
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