Nanostructured Bulk Ceramics (Part Ⅰ)

한영환,Amiya K. Mukherjee 한국세라믹학회 2009 한국세라믹학회지 Vol.46 No.3

The processing and characterization of ceramic nanocomposites, which produce bulk nanostructures with attractive mechanical properties, have been emphasized and introduced at Prof. Mukherjee’s Lab at UC Davis. The following subjects will be introduced in detail in Part ⅡI, Ⅲ, and Ⅳ. In Part Ⅱ, the paper will describe a three-phase alumina-based nanoceramic composite demonstrating superplasticity at a surprisingly lower temperature and higher strain rate. The next part will show that an alumina-carbon nanotube-niobium nanocomposite produced fracture toughness values that are three times higher than that of pure nanocrystalline alumina. It was possible to take advantage of both fiber-toughening and ductile-metal toughening in this investigation. In the fourth section, discussed will be a silicon-nitride/silicon-carbide nanocomposite, produced by pyrolysis of liquid polymer precursors, demonstrating one of the lowest creep rates reported so far in ceramics at the comparable temperature of 1400℃ This was first achieved by avoiding the oxynitride glass phase at the intergrain boundaries. One important factor in the processing of these nanocomposites was the use of the electrical field assisted sintering method. This allowed the sintering to be completed at significantly lower temperatures and during much shorter times. These improvements in mechanical properties will be discussed in the context of the results from the microstructural investigations. The processing and characterization of ceramic nanocomposites, which produce bulk nanostructures with attractive mechanical properties, have been emphasized and introduced at Prof. Mukherjee’s Lab at UC Davis. The following subjects will be introduced in detail in Part ⅡI, Ⅲ, and Ⅳ. In Part Ⅱ, the paper will describe a three-phase alumina-based nanoceramic composite demonstrating superplasticity at a surprisingly lower temperature and higher strain rate. The next part will show that an alumina-carbon nanotube-niobium nanocomposite produced fracture toughness values that are three times higher than that of pure nanocrystalline alumina. It was possible to take advantage of both fiber-toughening and ductile-metal toughening in this investigation. In the fourth section, discussed will be a silicon-nitride/silicon-carbide nanocomposite, produced by pyrolysis of liquid polymer precursors, demonstrating one of the lowest creep rates reported so far in ceramics at the comparable temperature of 1400℃ This was first achieved by avoiding the oxynitride glass phase at the intergrain boundaries. One important factor in the processing of these nanocomposites was the use of the electrical field assisted sintering method. This allowed the sintering to be completed at significantly lower temperatures and during much shorter times. These improvements in mechanical properties will be discussed in the context of the results from the microstructural investigations.

Nanostructured Bulk Ceramics (Part I)

Han, Young-Hwan,Mukherjee, Amiya K. The Korean Ceramic Society 2009 한국세라믹학회지 Vol.46 No.3

The processing and characterization of ceramic nanocomposites, which produce bulk nanostructures with attractive mechanical properties, have been emphasized and introduced at Prof. Mukherjee's Lab at UC Davis. The following subjects will be introduced in detail in Part II, III, and IV. In Part II, the paper will describe a three-phase alumina-based nanoceramic composite demonstrating superplasticity at a surprisingly lower temperature and higher strain rate. The next part will show that an alumina-carbon nanotube-niobium nanocomposite produced fracture toughness values that are three times higher than that of pure nanocrystalline alumina. It was possible to take advantage of both fiber-toughening and ductile-metal toughening in this investigation. In the fourth section, discussed will be a silicon-nitride/silicon-carbide nanocomposite, produced by pyrolysis of liquid polymer precursors, demonstrating one of the lowest creep rates reported so far in ceramics at the comparable temperature of $1400^{\circ}C$. This was first achieved by avoiding the oxynitride glass phase at the intergrain boundaries. One important factor in the processing of these nanocomposites was the use of the electrical field assisted sintering method. This allowed the sintering to be completed at significantly lower temperatures and during much shorter times. These improvements in mechanical properties will be discussed in the context of the results from the microstructural investigations.

The Indian Ocean: Historians Writing History

Mukherjee, Rila The Asian Association of World Historians 2013 The Asian review of world histories Vol.1 No.2

Tribute Issue: Remembering Ji-Hyung Cho

MUKHERJEE, Rila The Asian Association of World Historians 2015 The Asian review of world histories Vol.3 No.2

Organic phototransistors based on solution grown, ordered single crystalline arrays of a π-conjugated molecule

Mukherjee, Biswanath,Sim, Kyoseung,Shin, Tae Joo,Lee, Junghyun,Mukherjee, Moumita,Ree, Moonhor,Pyo, Seungmoon The Royal Society of Chemistry 2012 Journal of materials chemistry Vol.22 No.7

<P>High quality, single crystalline, ordered arrays of a π-conjugated organic molecule, <I>N,N′</I>-dioctyl-3,4,9,10-perylene tetracarboxylic diimide (PTCDI-C<SUB>8</SUB>), were grown by solution processing and used to fabricate a low-cost, high-performance organic phototransistor (OPT). The single crystalline nature of the microstructure was investigated using 2D-GIXD measurement. The organic field-effect transistor fabricated using periodic arrays of elongated crystals exhibited a photoresponsivity (<I>P</I>) of <I>ca.</I> 1 A W<SUP>−1</SUP> and a photo to dark current ratio (<I>I</I><SUB>on</SUB>/<I>I</I><SUB>off</SUB>) of 2.5 × 10<SUP>3</SUP> at <I>V</I><SUB>G</SUB> = 12 V and a maximum <I>P</I> of <I>ca.</I> 7 A W<SUP>−1</SUP> at the high gate bias regime (<I>V</I><SUB>G</SUB> = 50 V) with an optical power of <I>ca.</I> 7.5 mW cm<SUP>−2</SUP>. With polymeric gate dielectric, the OPT exhibited very stable n-type characteristics both in the dark and under light illumination and showed reproducible photo-switching behavior. The dependence of the photocurrent on the gate/drain voltage and on illumination intensity provided an effective way to control the number of photo-carriers generated in the active material, enabling the precise tuning of the device's performance. Performance comparison between OPTs with ordered crystal arrays and thin films of PTCDI-C<SUB>8</SUB> confirmed that the material's intrinsic properties were better realized in the crystalline device, presumably because of higher charge carrier mobility and better charge transport capability. This one-step, solution-based, self-assembly fabrication of multifunctional (photodetection, photoswitching, signal amplification) optoelectronic devices has potential to aid the development of organic semiconductors with high-quality micro/nanostructures for large-scale application and low-cost optoelectronic devices.</P> <P>Graphic Abstract</P><P>An organic phototransistor (OPT) was fabricated using solution grown, periodic arrays of PTCDI-C<SUB>8</SUB> single crystals. The OPT exhibited high photosensitivity (7 A W<SUP>−1</SUP>), high on/off current ratio (2.5 × 10<SUP>3</SUP>) and reproducible photo-switching at low optical power. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2jm14179e'> </P>

Targeted inhibition of galectin 1 by thiodigalactoside dramatically reduces body weight gain in diet-induced obese rats

Mukherjee, R,Kim, S W,Park, T,Choi, M S,Yun, J W Nature Publishing Group 2015 International Journal of Obesity Vol.39 No.9

Background:Galectin 1 (GAL1), an animal lectin is well characterized in the context of cancer, tumor environment, but its physiological roles in obesity remain to be demonstrated. In this study, we investigated whether targeted inhibition of GAL1 prevents obesity based on the previous observations that GAL1 is highly expressed in adipose tissues of high-fat diet (HFD)-induced obese rats.Methods:Lipogenic capacity of Lgals1 knocked down adipocytes was evaluated by determining the expression levels of major lipogenic markers using real-time PCR and immunoblot analysis. GAL1 partner proteins were identified using co-immunoprecipitation followed by protein mass fingerprinting. Finally, inhibitory effect of GAL1 by thiodigalactoside (TDG) was assessed in adipocytes and HFD-induced obese rats.Results:Knockdown of GAL1-encoding gene (Lgals1) attenuated adipogenesis and lipogenesis in both 3T3-L1 and HIB1B adipocytes. Further, direct treatment with TDG, a potent inhibitor of GAL1, to cultured adipocytes in vitro significantly reduced fat accumulation. Our animal experiment revealed that intraperitoneal injection of TDG (5 mg kg<SUP>−1</SUP>) once per week for 5 weeks in Sprague-Dawley (SD) rats resulted in dramatic inhibition of HFD-induced body weight gain (27.3% reduction compared with HFD-fed controls) by inhibiting adipogenesis and lipogensis as well as by increasing expression of the proteins associated with thermogenesis and energy expenditure.Conclusion:GAL1 has an essential role in HFD-induced obesity development. From a clinical viewpoint, pharmaceutical targeting of GAL1 using TDG and other inhibitor compounds would be a novel therapeutic approach for the treatment of obesity.

Gender-dependent Protein Expression in White Adipose Tissues of Lean and Obese Rats Fed a High Fat Diet

Mukherjee, Rajib,Choi, Jung-Won,Choi, Duk Kwon,Oh, Tae Seok,Liu, Hao,Yun, Jong Won S. Karger AG 2012 CELLULAR PHYSIOLOGY AND BIOCHEMISTRY Vol.29 No.3

<P>Proper understanding of molecular mechanisms underlying gender dimorphism in obesity for better nutritional recommendation is still in early stages. As white adipose tissues (WAT) is most important tissue in obesity metabolism, comparative proteomic analysis of all three WAT deposits at the same time to yield immensely important protein markers was the primary goal of this study.</P>

A comparative study of dragonfly inspired flapping wings actuated by single crystal piezoceramic

Mukherjee, Sujoy,Ganguli, Ranjan Techno-Press 2012 Smart Structures and Systems, An International Jou Vol.10 No.1

A dragonfly inspired flapping wing is investigated in this paper. The flapping wing is actuated from the root by a PZT-5H and PZN-7%PT single crystal unimorph in the piezofan configuration. The non-linear governing equations of motion of the smart flapping wing are obtained using the Hamilton's principle. These equations are then discretized using the Galerkin method and solved using the method of multiple scales. Dynamic characteristics of smart flapping wings having the same size as the actual wings of three different dragonfly species Aeshna Multicolor, Anax Parthenope Julius and Sympetrum Frequens are analyzed using numerical simulations. An unsteady aerodynamic model is used to obtain the aerodynamic forces. Finally, a comparative study of performances of three piezoelectrically actuated flapping wings is performed. The numerical results in this paper show that use of PZN-7%PT single crystal piezoceramic can lead to considerable amount of wing weight reduction and increase of lift and thrust force compared to PZT-5H material. It is also shown that dragonfly inspired smart flapping wings actuated by single crystal piezoceramic are a viable contender for insect scale flapping wing micro air vehicles.

Optimal adaptation decision-taking for terminal and network quality-of-service

Mukherjee, D.,Delfosse, E.,Kim, Jae-Gon,Wang, Yong IEEE 2005 IEEE transactions on multimedia Vol.7 No.3

In order to cater to the diversity of terminals and networks, efficient, and flexible adaptation of multimedia content in the delivery path to end consumers is required. To this end, it is necessary to associate the content with metadata that provides the relationship between feasible adaptation choices and various media characteristics obtained as a function of these choices. Furthermore, adaptation is driven by specification of terminal, network, user preference or rights based constraints on media characteristics that are to be satisfied by the adaptation process. Using the metadata and the constraint specification, an adaptation engine can take an appropriate decision for adaptation, efficiently and flexibly. MPEG-21 Part 7 entitled Digital Item Adaptation standardizes among other things the metadata and constraint specifications that act as interfaces to the decision-taking component of an adaptation engine. This paper presents the concepts behind these tools in the standard, shows universal methods based on pattern search to process the information in the tools to make decisions, and presents some adaptation use cases where these tools can be used.

Role of Fermentation in Improving Nutritional Quality of Soybean Meal - A Review

Mukherjee, Runni,Chakraborty, Runu,Dutta, Abhishek Asian Australasian Association of Animal Productio 2016 Animal Bioscience Vol.29 No.11

Soybean meal (SBM), a commonly used protein source for animal feed, contains anti-nutritional factors such as trypsin inhibitor, phytate, oligosaccharides among others, which limit its utilization. Microbial fermentation using bacteria or fungi has the capability to improve nutritional value of SBM by altering the native composition. Both submerged and solid state fermentation processes can be used for this purpose. Bacterial and fungal fermentations result in degradation of various anti-nutritional factors, an increase in amount of small-sized peptides and improved content of both essential and non-essential amino acids. However, the resulting fermented products vary in levels of nutritional components as the two species used for fermentation differ in their metabolic activities. Compared to SBM, feeding non-ruminants with fermented SBM has several beneficial effects including increased average daily gain, improved growth performance, better protein digestibility, decreased immunological reactivity and undesirable morphological changes like absence of granulated pinocytotic vacuoles.