One of the authors developed the high strength and high conductivity Cu-24 wt% Ag alloy as a conductor material for high field magnets twenty years ago.Wire and sheet of the alloy have been used as a conductor material for pulsed magnets or resistive magnets of the high magnetic field facilities of each country. However, the alloy required large quantities of Ag addition to achieve high strength. The cost performance and workability of the alloy were not good for that. So, we investigated possibility of low Cu-Ag alloy for decreasing in material cost and improving in workability. We succeeded in the development of the Cu-6 wt% Ag alloy by the new heat treatment which is superior to the characteristic of the Cu-24 wt% Ag alloy even if the amount of Ag content is decreased in 1/4.

At present, we make a lot of high field pulsed magnets by using the Cu-6 wt% Ag wire manufactured industrially, and do that magnetic field experiment and are getting good results at the ISSP, the university of Tokyo. We will talk about the characteristic, new heat treatment method and the manufacturing process of the conductor material for the Cu-6 wt% Ag alloy.

The environmental impact resulting from the use of fossil fuel as an energy source affects the entire globe. Eventually, fossil fuels will no longer be a reasonable source of energy and alternative energy sources will be needed. Thermoelectric materials (TE) that directly convert heat into electricity are a viable option to replace the conventional fossil fuel because they are reliable, cost effective, and use no moving parts. Recently researchers discovered the existence of giant Seebeck coefficient in manganese oxide (MnO2) powders, which ignited an increased interest in MnO2-based materials. In this work we present a systematic structural and electrical characterization of amorphous and crystalline MnxOy thin films. These films were deposited at room temperature on heated silicon and sapphire substrates by DC Magnetron Sputtering. Our preliminary results show that MnxOy/silicon thin films undergo a crystalline change from Mn2O3 to Mn3O4 as annealing temperature is increased from 300°C to 500°C.

Most dielectric materials have very weak electro-optic properties, whereas the optical properties of some plasmonic materials may be greatly tuned, especially around their plasma frequency, where dielectric constant is transiting between positive (“dielectric state”) and negative (“metallic state”) values. In this talk, we will review some of our recent work on electro-optical modulation and introduce a new concept, photonic MOS based on “optical property inversion”. This concept may provide inspiration for the development of nanophotonic devices. While the whole paper only discusses theory and modelling, some new experimental results will be presented in the on-site talk. Throughout this report, “static dielectric constant”, ɛ, refers to material dielectric constant in the DC or radio frequency (RF) regime; “optical dielectric constant”, ε, represents material dielectric constant in the near-infrared regime. This paper was re-written based on an Arxiv file [1].

The multiferroic material Bi1-x SmxFeO3 shows ferroelectric and antiferromagnetic properties inthe ground state of the Bi-rich side. When the Sm content increases fromx = 0 in BiFeO3, the (ferroelectric-R3c→ paraelectric-Pnma) state change occurs around x= 0.14. According to the previous studies onBi1-x SmxFeO3, the state boundary between the R3c and Pnma states can beidentified as a morphotropic phase boundary (MPB), which is nearly parallel tothe temperature axis in the state diagram. The notable feature ofBi1-x SmxFeO3 is that a remarkable piezoelectric response was also foundnear the MPB. However, the origin of the remarkable response has not beenunderstood sufficiently. In this study, thus, the crystallographic features inthe vicinity of the MPB have been examined by x-ray powder diffraction andtransmission electron microscopy. It was confirmed that the R3c and Pnma stateswere present for 0 ≤ x ≤ 0.15 and for0.16 ≤ x ≤ 0.30, respectively. Inaddition to these states, there also existed the PbZrO3-type statearound x = 0.15, which was identified as a modulatedstructure. Based on the analysis of the modulated structure, furthermore, it wassuggested that the PbZrO3-type state could be regarded as a 2q state,which is characterized by two transverse modulation waves with k1= [1/2 0 0]o and k2 = [0 1/20]o in the orthorhombic-Pnma notation.

We investigated the fabrication of diamond-like carbon (DLC) emitter patterns by room-temperature curing nanoimprint lithography (RTC-NIL) with polydimethylsiloxane (PDMS) molds using polysiloxane, as an application to the emitter for the next generation flat panel display.

The DLC which has excellent properties similar to diamond properties was used as a pattern material. A PDMS was used as a mold material and fabricated by the following optimum conditions of the first curing time at RT for 36 h and the second curing time at the temperature of 150 °C for 15 mins. The polysiloxane is in the state of sticky liquid at RT and stable in air. Therefore, the polysiloxane was used the electron beam (EB) resist and oxide mask material in EB lithography, and also used as RT-imprint material.

First, we fabricated the PDMS mold with pit array. Each dot is 5 µm-diameter and 400 nm-depth. We carried out the RTC-NIL process with PDMS molds using polysiloxane under the following optimum imprint conditions of 0.5 MPa-imprinting pressure, 1.5 min-the time between spin-coat and imprint, and 5 min-imprinting time. Next, the residual layer of imprinted polysiloxane pattern was 450 nm and then was removed with electron cyclotron resonance (ECR) trifluoromethane (CHF3) ion shower under the conditions of 300 eV-ion energy and 3 min-etching time. Then, we processed the imprinted polysiloxane patterns on the DLC film with an ECR oxygen (O2) ion shower under the conditions of 400 eV-ion energy and 12 min-etching time. As a result, we succeeded in fabricating convex DLC emitter patterns with high accuracy which has 5 µm-diameter and 500 nm-height.

Sci-Toons is a new, experimental, teaching and learning approach that engages students in materials science research via interaction with experts, narrative, visual representations, iterative feedback and multimedia platforms. Based on a model (the Multimedia Theoretical Learning Framework) and multimedia design principles, Sci-Toon Creation Group (SCG) members, which include both science and non-science majors, work with faculty to produce video animations dealing with scientific topics. The creative process of producing scripts for two selected Sci-Toons videos dealing with materials science subjects (Graphene and Conductive Polymers) are discussed; initial and final versions of each are combined through use of Word Clouds.

The videos that are produced are distributed via the internet, providing instruction and information about materials sciences and other STEM topics. Demographic data about the types of individuals downloading these Sci-Toons are provided.

We conclude that Sci-Toons can be used in both formal and informal educational settings for science learning and teaching as well as in communicating materials science concepts to broad audiences including females and underrepresented minorities students.

The swelling stress of bentonite which is one of the engineered barriers and backfill materials for radioactive waste disposal is strongly dependent on water chemistry such as saline water. The authors have developed a thermodynamic model for calculating the swelling stress (pressure) of bentonite, based on the thermodynamic data of interlayer water in Na-montmorillonite obtained in earlier studies. In this work, the swelling stress of water-saturated Na-bentonite was calculated for various bentonite dry densities and solution conditions such as sodium chloride concentration and nitrate concentration and compared to the measured data.

Swelling stress versus montmorillonite partial density was estimated for solutions containing sodium chloride ([NaCl] = 0−3.4 m, m: molality) and nitrate concentrations ([NaNO3] = 0−6 m) and compared to data measured for bentonites with various montmorillonite contents and silica sand contents. The calculated swelling stresses commonly decreased with increasing [NaCl] and [NaNO3] for the same montmorillonite partial density. The trend of swelling stress versus [NaCl] was in a good agreement with the measured results. The calculated swelling stress versus [NaCl] was also quantitatively in a good agreement within the scattering of the measured data. The trend versus [NaNO3] was also similar to that versus [NaCl]. However, the calculated results were quantitatively different from the measured data ([NaNO3] = 3, 5 m, montmorillonite partial density = 0.76−0.87 Mg/m3). Even though those measurements were conducted under the condition of high ionic strength, the measured data of swelling stresses were almost the same as in the condition of distilled water. Since the measurement periods were quite rather short, it is conceivable that the measurements were not done at equilibrium.

Nanostructured quantum well and quantum dot solar cells are being widely investigated as a means of extending infrared absorption and enhancing photovoltaic device performance. In this work, we describe the impact of nanostructured layer number on the performance of flexible, highvoltage InGaAs/GaAs quantum well solar cells. Multiple quantum well structures are observed to have a higher short circuit current but a lower open circuit voltage than similar single quantum well structures. Analysis of the underlying dark diode characteristics indicate that these highvoltage structures are limited by radiative recombination at high bias levels. The results of this study suggest that future development efforts should focus on maximizing the current generating capability of a limited number of nanostructured layers and minimizing recombination within the nanostructured absorber.

The major aim of the present study is to develop and explore the potential of large surface area electrospun polymer nanofabric as a carrier for controlled and sustained release, in particular for hydrophobic drugs. Gelatin (type A), FDA approved natural polymer was electrospun in a mixture of solvent (20% acetic acid in water) to yield long, continuous and uniform fibers with average diameter ∼ 200 nm. Piperine was chosen as a model hydrophobic drug in this study. As gelatin is highly soluble in aqueous medium, we crosslinked electrospun gelatin nanofibers using saturated GTA vapor to increase the water resistive properties. For controlled release over a period of 12 h, we devised several strategies to vary the crosslinking conditions and accordingly understand their effect on drug release mechanism. One of such successful efforts was based on deposition of multiple layers of electrospun fabric by sandwiching between drug loaded gelatin nanofibers and without drug gelatin nanofibers from both sides. Not only the layer by layer deposition, we also crosslinked the different layer in the same sequential way. Sequential crosslinking using GTA vapor in different layers of the fabric, helped in uniform crosslinking throughout the thickness compared to crosslinking after final deposition in the form of a single layer. Effect of different crosslinking strategies was investigated in terms of surface morphology and drug stability. Finally, in-vitro release study was performed maintaining the physiological conditions mimicking GI tract to analyze the effect of crosslinking on the drug release profile. The in-vitro studies concluded that the controlled drug release can be achieved by tuning the thickness of individual fabric layer followed by their sequential crosslinking, which finally affects the diffusional barrier for drug release. Interestingly, we also found that only 6 min exposure to saturated GTA vapor is sufficient to provide the required drug release in contrast to up to 24 h as reported in literature. This finding also addresses the toxicity problem associated with the use of GTA as a cross-linker.

Long wavelength acoustic phonons are normally weakly coupled to other vibrational modes in a crystalline system. This is particularly problematic in molecular dynamics calculations where vibrations at the system-size scale are typically excited at initiation. The equilibration time for these vibrations depends on the strength of coupling to other modes, so is typically very long. A very simple deterministic method is presented which removes this problem. Examples of equilibration in lithium and a martensitic phase transition in sodium are used to demonstrate the method.

We report on progress with PL imaging applications in silicon solar cell production, specifically focusing on the characterization of silicon bricks prior to wafer cutting. Silicon bricks represent an ideal opportunity to characterize and quantify the electronic material quality at an early stage of the PV value chain. Quantitative data on bulk lifetime can be obtained on bricks without any specific sample preparation, unlike unprocessed wafers. Spatially resolved bulk lifetime, interstitial iron concentration, and defect density measurements are demonstrated on bricks from different manufacturers including both high performance multicrystalline and older generation multicrystalline bricks. We find significant variability in bulk lifetime and iron concentration across the samples which is not related to its date of manufacture. However we do see a qualitative reduction in crystallographic defects in the newer high performance multicrystalline bricks. Data is parameterized in different ways to suggest possible paths to better predict solar cell efficiencies from an early stage of inspection.

Brick level PL measurements were previously performed using a conventional area scanning PL imaging system, which is associated with light spreading artefacts of weakly absorbed light. To overcome these artefacts, a new line scanning photoluminescence imaging system is used. We show a reduction in contrast smearing between high- and low lifetime regions in the new setup leading to image quality suitable for defect detection and quantitative measurements without deconvolution correction.

The performance of a novel type of NdFeB micromagnets fabricated by agglomerationof magnetic powder by atomic layer deposition is investigated. The ALD-bondedmicromagnets can withstand standard BEOL (back-end of line) processing and heattreatments at temperatures of up to 400 °C in air and vacuum withoutany significant impact on the demagnetization curves. By optimized packingdensity a remanence of 660 mT is realized for the micromagnets. The coercivityµ0Hc = 890 mT remains constant forall samples and corresponds to the powder value.

A comparison of the demagnetizing behavior of micromagnets with theory of solidbody magnets prove that the influence of particle shape and hollow spaces ondemagnetizing field is low. Hence, a similar impact of shape on stray field andforces as for solid body magnets can be assumed when integrating NdFeBALD-bonded micromagnets in applications.

Tin sulfide has emerged as a promising solar absorber among the IV-VI binary compound which is earth-abundant and non-toxic. This research provides a new perspective on synthesis of photosensitive monophasic SnS films by organic chemical vapor sulfurization of Sn thin film. S-radicals formed by closed space pyrolysis of di-tert-butyl disulfide (TBDS) diffusively react with Sn to produce SnS film. SnS being an amphoteric semiconductor converts to n-type by trivalent Sb and Bi dopants. The organic vapor sulfurization method described in this research facilitates single-step synthesis of buried junction structures and thus SnS solar cells in a p-n homojunction or p-i-n structures. In this work, vacuum evaporated Sn thin film with a thickness of 100 nm, was converted to SnS by sulfurization under 100 sccm flow of TBDS vapor preheated to 100°C and structural phase evolution and film growth kinetics were investigated for sulfurization at 200°C, 300°C and 400°C for a periods 90 min. X-ray diffraction studies establish single phase highly crystalline film in orthorhombic crystal structure forms at 200°C. Raman scattering results confirm SnS formation with the identification of 2Ag, 2B2g optical phonons modes. Optical bandgap studies confirm a low energy 1.1-1.4 eV indirect bandgap and a strong absorption threshold between 1.4 to 1.6 eV direct band gap depending on the sulfurization conditions correlating with intrinsic defects and phase structure of the film.

The discovery of graphene based materials has led to significant advancement in several different areas. The large surface area, nanoporous structure and availability of delocalized electron network provide a unique opportunity for purification of solvents via adsorption, absorption or simple trapping. This makes graphene based materials as potential candidates for purification and desalination of water. Here we report synthesis of 3D porous network of oxidized graphene for purification of sea water. The membranes fabricated using these frameworks are hierarchically linked intrinsically defected oxidised graphene sheets by long micro-channels and capable of filtering small ions such as Na+ and Cl-. These are easy to fabricate, reusable and economically viable especially for point of use application. We finally show a fabricated device using membrane made from these 3D networks of oxidized graphene.

Thin-film transistors (TFT) were fabricated at a room-temperature (RT) with zincoxide (ZnO) channel and indium molybdenum oxide (IMO) electrodes. To isolate thegate oxide and gate electrode influence on the device performance, common gateconfiguration on a commercial substrate with thermal SiO2 (100 nm)was selected. A threshold voltage (V Th) of 10 V and I ON/I OFF ratio of 1 × 10-5 were obtained. Once the referencedata was taken transistors were exposed to glycerol. Temporary changes in devicecharacteristics were observed due to the influence of glycerol, a lowconductivity medium. To exclude the possibility of sugar alcohol being the mainconductor, measurement on dummy transistor electrode was performed retaining thedistance between probes. The TFT device under test revealed ten times higherdrain current but also a change in threshold voltage and leakage current.Transistors under glycerol influence were always open with the positive gatebias.

The high-temperature performance of electronics packages was studied at 180°C, 200°C and 240°C for 3,000h. The structure tested consisted of a fairly large silicon chip attached with anisotropic conductive adhesive (ACA) onto an adhesiveless PI substrate. These structures showed good electrical reliability at 180°C. Several early failures were seen at the other temperatures. However, only 23% of the test samples failed at 200°C, while considerably more failures were seen at 240°C. The results showed that good high-temperature reliability can be achieved with polymer interconnections. However, the exposure time should be limited, especially at very high temperatures, to avoid failures caused by the materials becoming brittle.

Nanocrystalline cellulose (NCC) is an emerging renewable nanomaterial that ispromising for many diverse applications. As a renewable material, NCC and itsderivatives have been widely studied, focusing on their biological, chemical, aswell as mechanical properties. The electro-optical properties of NCC, however,remain relatively under explored. Birefringence is one of the importantproperties that make the NCC very attractive for photonic applications. Therode-like NCC fibers dispersed in certain solutions exhibit a specific preferredorientation which depends on their electrical charge, physical dimensions andthe type of solutions used to disperse NCC fibers. In a recent study ofKerr-effect in functionalized NCC solutions, we demonstrated that it is possibleto control the orientation of NCC fibers under an applied electric field.NCC-based spatial light modulator devices were fabricated and characterized.Results showed that the transmittance of the device can be controlled throughfrequency modulation of the applied electric field. In this paper we present thefabrication and electro-optical characterization of the device and discuss therelevant properties of NCC and future approaches to optimize and improve theircharacteristics and performance.

New material phases formed under non-equilibrium conditions at pressures above 100 GPa and temperatures exceeding 104K, the conditions of the warm dense matter (WDM), have become accessible using micro-explosions triggered by ultra-short sub-1 ps pulses tightly focused into micro-volume with cross sections comparable with the wavelength of light. Laser-induced micro-explosions convert a material in a focal volume into a non-equilibrium disordered plasma state confined inside the bulk of pristine crystal. Ultra-high quenching rates overcome kinetic barriers to the formation of new metastable high pressure phases, which are preserved in the surrounding pristine crystal for following recovery and exploitation. Direct laser writing was used to pattern large areas by closely packed arrays of the microexplosion modified sites for structural characterisation of the minute volumes of nano-materials with transmission electron microscopy, diffraction and synchrotron X-ray diffraction. The method of ultrafast-laser induced confined microexplosion is demonstrated for modification and creation of new phases in case of bcc-Al inside sapphire, valence change of Fe-ions in olivine, formation of new tetragonal bt8 and st12 phases of silicon, Ge and O separation in GeO2 glass and molecular oxygen formation inside voids at the site of microexplosion inside glasses.

Poly(N-isopropylacrylamide) (PNIPAM) has been used extensively for numerous biomedical applications. However, there is not enough information in the literature on the wettability and hygroscopic properties of electrospun PNIPAM fibers, relevant for water harvesting applications. This study focuses on investigating the wettability and hygroscopic properties of electrospun PNIPAM fibers at room temperature and elevated temperature. The wettability properties of electrospun PNIPAM fibers were compared to spin-coated PNIPAM thin films. The wettability properties of the electrospun fibers were enhanced by 56% compared to spin-coated films. Water contact angle (WCA) measured on electrospun fibers was determined to be 137° at elevated temperatures while WCA on spin cast PNIPAM film was determined to be 81° at elevated temperatures. Furthermore, hygroscopic properties of the electrospun PNIPAM fibers were studied using thermogravimetric analysis (TGA). The PNIPAM fibers are seen to exhibit moisture absorption capacity of about 16.6 wt. % under humid conditions.

While the quest for understanding and even mimicking biological tissue has propelled, over the last decades, more and more experimental activities at the micro and nanoscales, the appropriate evaluation and interpretation of respective test results has remained a formidable challenge. As a contribution to tackling this challenge, we here describe a new method for identifying, from nanoindentation, the elasticity of the undamaged extracellular bone matrix. The underlying premise is that the tested bovine bone sample is either initially damaged (i.e. exhibits micro-cracks a priori) or that such micro-cracks are actually induced by the nanoindentation process itself, or both. Then, (very many) indentations may relate to either an intact material phase (which is located sufficiently far away from micro-cracks), or to differently strongly damaged material phases. Corresponding elastic phase properties are identified from the statistical evaluation of the measured indentation moduli, through representation of their histogram as a weighted sum of Gaussian distribution functions. The resulting undamaged elastic modulus of bovine femoral extracellular bone matrix amounts to 31 GPa, a value agreeing strikingly well both with direct quasi-static modulus tests performed on SEM-FIB-produced micro-pillars (Luczynski et al., 2015), and with the predictions of a widely validated micromechanics model (Morin and Hellmich, 2014). Further confidence is gained through observing typical indentation imprints under Scanning Electron Microscopy (SEM), which actually confirms the existence of the two types of micro-cracks as described above.