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Abrupt change of dielectric properties in mullite due to titanium and strontium incorporation by sol-gel method

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Journal of Advanced Ceramics 2014年第4期3卷 278-286页

作者： Biplab Kumar PAUL Kumaresh HALDAR Debasis ROY Biswajoy BAGCHI Alakananda BHATTACHARYA sukhen das Physics Department Jadavpur UniversityKolkata-700032India

Highly crystallized mullite has been achieved at temperatures of 1100℃and 1400℃by sol-gel technique in presence of titanium and strontium ions of different concentrations:G_(0)=0 M,G_(1)=0.002 M,G_(2)=0.01 M,G_(3)=0.02 M,G_(4)=0.1 M,G_(5)=0.2 M and G6=0.5 M.X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR),field emission scanning electron microscopy(FESEM),LCR meter characterized the *** formation was found to depend on the concentration of the *** dielectric properties(dielectric constant,loss tangent and AC conductivity)of the composites have been measured,and their variation with increasing frequency and concentration of the doped metals was *** the experiments were performed at room *** composites showed maximum dielectric constants of 24.42 and 37.6 at 1400℃of 0.01 M concentration for titanium and strontium ions at 2 MHz,*** to the perfect nature of the doped mullite,it can be used for the fabrication of high charge storing capacitors and also as ceramic capacitors in the pico range.

关键词： mullite sol-gel technique X-ray diffraction(XRD) dielectric properties field emission scanning electron microscopy(FESEM)

Reduced Activation Energy of Iron and Copper Ion Doped Mullite which Can Be Used as a Substrate in Electronic Industry

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Journal of Surface Engineered Materials and Advanced Technology 2013年第3期3卷 11-17页

作者： Debasis Roy Kumaresh Haldar Biplab Kumar Paul Alakananda Bhattacharya sukhen das Papiya Nandy Physics Department Jadavpur University Kolkata India.

The crystallized mullite composite has been synthesized via sol-gel technique in the presence of transition metal ions such as iron and copper. The electrical resistivity and activation energy of the composites have been measured and their variation with concentration of the metal ion has been investigated. The resistivity of doped mullite decreases rapidly in the shorter temperature range and sharply in the higher temperature range. The decreasing resistivity is due to the 3d orbital electrons and the concentration of metal ions present. X-ray analysis confirms the presence of metal ions in mullite, which entered in the octahedral site. The Fe2+ and Cu2+ ions will substitute Al3+ ion in the octahedral site of mullite structure and most probably will be responsible for reducing the resistivity as well as the activation energy. Transition metal ion doped mullite-based ceramic can be considered as promising material as a substrate in the electronic industry, because of its reasonable atom density, its low activation characteristics, low thermal expansion coefficient and high mechanical strength. The present material we have developed has an activation energy of resistivity/band gap energy, Eg, 1.11 eV at 0.04 M concentration for Cu2+ ion.

关键词： Nanostructures Sol-Gel Growth X-Ray Diffraction Scanning Electron Microscopy (SEM) Electrical Conductivity

Four-step spin-crossover in an oxamide-decorated metal-organic framework

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Chinese Chemical Letters 2022年第3期33卷 1381-1384页

作者： Siguo Wu sukhen Bala Zeyu Ruan Guozhang Huang Zhaoping Ni Mingliang Tong Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education School of ChemistrySun Yat-Sen UniversityGuangzhou 510275China

Spin-crossover(SCO)complexes with multiple spin states are promising candidates for high-order magnetic storage and multiple ***,by employing the N,N'-4-dipyridyloxalamide(dpo)ligand,we synthesize two Hofmann-type metal-organic frameworks(MOFs)[Fe(dpo){Ag(CN)_(2)}_(2)]·3DMF(1)and[Fe(dpo){Ag(CN)_(2)}_(2)]·0.5MeCN·2DEF(2),which exhibit guest dependent four-step SCO behaviors with the sequences of LS→~LS_(2/3)HS_(1/3)→LS_(1/2)HS_(1/2)→~LS_(3/10)HS_(7/10)→HS and LS→~LS_(2/3)HS_(1/3)→LS_(1/2)HS_(1/2)→~LS_(1/4)HS_(3/4)→HS,***,the incorporation of hydrogen-donating/hydrogen-accepting groups into the Hofmann-type MOFs may effectively explore the multi-step SCO materials by tuning hydrogen-bonding interactions.

关键词： Spin crossover Oxamide Metal-organic framework Hofmann-type Host-guest interaction

Genetic Diversity and Interrelationship Among Mulberry Genotypes

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Journal of Genetics and Genomics 2007年第8期34卷 691-697页

作者： Rita Banerjee sukhen Roychowdhuri Haradhan Sau Bimal Kumar das Pannalal Ghosh Beera Saratchandra Central Sericultural Research and Training Institute

Fourteen morphometric traits were used to examine the genetic divergence of 25 mulberry （Morus spp.） genotypes from varied agroclimatic conditions of India. Wide variation was observed for all the traits. The genotypes irrespective of their place of collection were grouped into 10 different clusters. Seven accessions, that is, Baragura-2, Gorabandha-2, Kalimpong, Herbertpur, Kollegal, Resham majri-7, and UP-14 each a cluster of unique entries will be of useful for genetic resources. Nevertheless, the correlation and path analysis suggest the direct selection of lamina length, fresh leaf weight, leaf area, and single leaf weight will be rewarding for mulberry leaf yield improvement.

关键词： mulberry morphometric traits genetic divergence correlation path analysis

五配位单核钴配合物的单晶结构和磁性能（英文）

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无机化学学报 2019年第5期35卷 910-914页

作者：张翠娟 sukhen Bala 倪兆平童明良中山大学化学学院生物无机与合成化学教育部重点实验室广州510275

制备了五配位单核钴配合物[Co(TMC)Cl]ClO_4(1,TMC=1,4,7,10-tetramethyl-1,4,7,10-tetraazacyclododecane)。配合物1结晶于单斜晶系:P21,晶胞参数为a=0.805 95(7) nm,b=1.486 58(12) nm,c=0.813 64(7) nm,β=110.190(2)°,V=0.914 93(13) nm^3,Z=2,T=120(2) K。钴与来自TMC配体的4个氮原子和1个氯离子配位,形成了扭曲的四方锥配位构型。磁性测试揭示了高自旋的钴离子具有场诱导的慢弛豫行为。

关键词：五配位钴(Ⅱ)配合物磁性能

Variability, heritability and genetic advance in mulberry (<i>Morus</i>spp.) for growth and yield attributes

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Agricultural Sciences 2012年第2期3卷 208-213页

作者： Subramaniam Gandhi Doss Shyama Prasad Chakraborti sukhen Roychowdhuri Nirvan Kumar das Kunjupillai Vijayan Partha Dev Ghosh Mala V. Rajan Syed Mashayak Hussaini Qadri Central Sericultural Research and Training Institute Berhampore India Central Sericultural Research and Training Institute Mysore India Central Silk Board BTM Layout Bangalore India Department of Botany University of Kalyani Kalyani India Research Extension Center Nabagram India

Genetic improvement of crop plants is brought about by manipulating the genetic makeup through systematic breeding techniques or by employing modern biotechnological tools. Application of systematic breeding technique to a large extent is decided by the knowledge on the genetic control of the traits. Keeping this in view, nine mulberry genotypes were evaluated for different growth and yield attributing traits viz., number of tillers (NT), plant height (PH), total shoot length (TSL), nodal distance (ND), leaf fall % (LF), number of leaves/plant (NLP), weight of 100 fresh leaves (WFL), weight of 100 dry leaves (WDL), single leaf area (LA), leaf area index (LAI), aboveground biomass (AGB), leaf harvest index (LHI) and leaf yield (LY) and estimated the magnitude of genotypic and phenotypic variation, heritability, genetic advance and correlation coefficients. The broad sense heritability for these traits ranged from 63.942 (WFL) to 13.261 (PH). High heritability coupled with high genetic advance was recorded for the characters WFL, LF, LA, WDL and LY suggesting the higher genetic control over these traits. Leaf yield showed significantly positive phenotypic and genotypic correlations with all other growth traits except PH and LF. Leaf fall had significant negative correlations with all the highly heritable yield attributes viz., ND (-0.379), WDL (-0.225), LA (-0.346), LAI (-0.233) at 1% level and AGB (-0.148), LHI (-0.122) and LY (-0.146) at 5% level. Likewise, it showed positive correlations with TSL (0.558), NLP (0.264) and PH (0.221). Since mulberry is mainly cultivated for leaf yield, genotypes having higher WFL, LA, WDL and LY and less LF must be given importance during parent selection to evolve high yielding varieties with less leaf fall across different seasons in mulberry.

关键词： Variability Heritability Genetic Advance Yield Attributes Low Leaf Senescence