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Nanostructure, chemical composition and size distribution of aerosols have prime important effects on their efficiency in heterogeneous ice nucleation (HIN). The ice nucleation usually requires active sites in the aerosols in order to act as ice nuclei (IN). In this study, HIN and probable active sites of the graphene-graphene oxide nanoparticles (GGON), obtained from graphite oxide by low temperature thermal shock (LTTS), were investigated. Characteristics and size distribution of the GGON were identified using scanning electron microscope (SEM) and image processing of the results, Fourier transform infrared spectroscopy (FTIR), Raman spectra and X-ray diffraction (XRD) of their sheets. The FTIR spectra indicate stronger carbon-oxygen bonds in the samples obtained by LTTS. In addition, maximum size distribution of the GGON was ranged around 160–180 nm. After introducing these particles in the cloud chamber, HIN has occurred and ice crystals were formed. Size distribution of crystals were obtained from image processing of the plates, where covered by a thin layer of Formvar, showed the number of ice crystals in the GGON were increased as temperature increased from −20 °C to −10 °C. In addition, two possible mechanisms of asymmetry and deformation in ice crystals of the GGON were described.

With the increased use of nanocelluloses as additives in many industrial applications, better characterization methods are needed to ensure their effectiveness. Transmission electron microscopy (TEM) is an appropriate image acquisition system to enable their morphological characterization. The use of TEM has typically been focused on determining the diameter and length of individual cellulose nanocrystals (CNCs) or nanofibers (CNFs), so different dispersion practices, such as sonication or the use of dispersants, are commonly applied to separate the particles. However, this study aims to improve the characterization of the bulk morphology of CNCs and CNFs by TEM, taking steps towards the determination of the aggregation/dispersion degree as well as the fibrillation degree of CNFs. TEM has been investigated with two types of grids (holey and Formvar/carbon), three different fixing methods (Poly-l-Lysine, glow discharge and UV radiation) and the use of negative staining. Fractal dimension and lacunarity were used to quantify the reproducibility of the improved method. With the use of Poly-l-Lysine, the attachment of CNCs and CNFs particles on the TEM grids was ensured, due to the electrostatic interactions between negatively charged nanocelluloses and positively charged and hydrophilic Poly-l-Lysine surfaces. The low value of lacunarity, close to 0.3, shows a very high reproducibility of the methodology proposed. With this new approach, the state that the nanocelluloses have in suspension can be directly characterized by TEM.

We aimed to develop an artificial membrane system to observe the infection process of the obligate biotrophic powdery mildew fungi without the use of living plant cells. The conidia of Blumeria graminis and Erysiphe pisi conidia were inoculated on a formvar membrane laid on an artificial medium. Germinated conidia frequently formed appressoria and then penetrated the membrane to form haustorium-like structures in the artificial medium. Secondary hyphae elongation was also observed after the formation of haustorium-like structures. These results suggested that the formvar membrane laid on artificial medium induced the formation of haustorium-like structures that have roles in the formation of secondary hyphae.

The stopping power of Formvar and Mylar polymeric materials for energy region (0.1 to 1.0) MeV/nucleon 19F, 23Na, 24Mg, 27Al, 28Si, 31P, 32S, 35Cl, and 40Ar ions have been determined. The energy lo...

Single-shot laser-induced damage threshold (LIDT) measurements of multi-type free-standing ultrathin foils were performed in a vacuum environment for 800 nm laser pulses with durations τ ranging from 50 fs to 200 ps. The results show that the laser damage threshold fluences (DTFs) of the ultrathin foils are significantly lower than those of corresponding bulk materials. Wide band gap dielectric targets such as SiN and formvar have larger DTFs than semiconductive and conductive targets by 1–3 orders of magnitude depending on the pulse duration. The damage mechanisms for different types of targets are studied. Based on the measurement, the constrain of the LIDTs on the laser contrast is discussed.

Strains in graphene play a significant role in graphene-based flexible devices, but many aspects of the domain boundary effects in strained graphene remain unclear, such as the evolution of Raman spectra. Here we present a systematic investigation on the domain boundary effects on the Raman spectra of strained graphene, using a designed strong interface formed by formvar resins. We achieve in single-crystal graphene by far the largest strain up to 2%, significantly improved from the previous highest value of 1.3%, as well as the redshift and splitting for its G and 2D peaks. More importantly, the Raman spectra of strained bi-crystal graphene with a domain boundary show that the spectral evolution follows the same trend as the single crystal, and this trend was also confirmed by the result in polycrystalline graphene, demonstrating that the straining effect on the G and 2D peaks of graphene at strong interfaces is actually independent of its domain boundaries, different from the previous report of graphene deposited on weak interfaces. We attribute it to the efficient interfacial stress transfer at the formvar interfaces, and believe they can provide new insights into the understanding of graphene mechanical behaviors and valuable guidance for graphene-based flexible electronics.

Characterization of cellulose nanocrystals (CNCs) is often complex and tedious. With their increased use for biological materials, polymer reinforcing agents, and other applications, better characterization methods of CNCs are needed to ensure product quality. However, because of their small size, hydrogen bonding, and low electron density, individual CNCs are difficult to image with high resolution and magnification using electron microscopy. Methods to help counter these challenges include staining for increased contrast and techniques to increase dispersion. This work tested several stains, dispersing agents, and sample supports to find a consistent method of individualizing CNCs and providing good contrast for imaging in transmission electron microscopy (TEM). The most consistent method found uses a low concentration of CNCs, bovine serum albumin as a dispersing agent, and Nanovan® as the contrasting stain on a silicon monoxide-coated Formvar TEM grid.

Prion and some other incurable human neurodegenerative diseases are associated with misfolding of specific proteins, followed by the formation of amyloids. Despite the widespread usage of the transmission electron and of the atomic force microscopy for studing such amyloids, many related methodological issues still have not been studied until now. Here, we consider one of the first amyloids found in Saccharomyces cerevisiae yeast, i.e. Sup35NMp, to study the adsorption of monomeric protein and its fibrils on the surface of mica, silica, gold and on formvar film. Comparison of linear characteristics of these units calculated by processing of images obtained by the atomic force, transmission and scanning electron microscopy was carried out. The minimal number of measurements of fibril diameters to obtain the values in a given confidence interval were determined. We investigated the film formed by monomeric protein on mica surface, which veiled some morphology features of fibrils. Besides, we revealed that parts of the Sup35NMp excluded from the fibril core can form a wide “coat”. The length of the protein forming the core of the fibrils was estimated.

Dopamine modified γ-polyglutamic acid (γ-PGA-DA) copolymer and melamine (Mel) can self-assemble into Mel/γ-PGA-DA micelles via weak intermolecular interactions in aqueous solution containing small amount of methanol. When Mel/γ-PGA-DA micellar solution was cast on the surface of formvar stabilized with carbon support films, the lotus-like nano-architectures were formed on the surface of substrate via hierarchical assembly of micelles. The size of lotus-like nanoarchitectures was approximately 200 nm×500 nm. The possible driving forces for hierarchical assembly of micelles were the solution fluid and interaction between micelles. The hierarchical assembly of micelles was similar to the fractal aggregation of inorganic particles and a possible reason was discussed.

We report a formvar assisted transfer method to make graphene TEM grids having single layer graphene. Our method uses formvar instead of PMMA as the polymer support and produces clean graphene. Formvar was easily removed by dissolving in chloroform and did not leave residues after removal because of the lower the molecular weight. Our transfer method achieved the higher average coverage (about 55%) than direct transfer method (about 5%). Since mesh grids were not exposed to a metal etchant solution during our transfer process, the mesh grid material for graphene transfer was not limited. Our graphene transfer method produces high quality and single layer graphene for a graphene TEM grid. Consequently, the formvar assisted graphene transfer method solves disadvantages of polymer support method and direct transfer.

Atmospheric aerosol particles were collected in Budapest, Hungary in April–June onto lacey Formvar substrates by using an electrostatic precipitator during the beginning phase of the particle growth process in ten nucleation and growth events. Median contribution of the nucleated particles - expressed as the concentration of particles with a diameter between 6 and 25 nm to the total particle number concentration – was 55%, and the median electrical mobility diameter of the particles was approximately 20 nm. The sample was investigated using high-resolution transmission electron microscopy (TEM) and electron energy-loss spectroscopy. Major types of individual particles such as soot, sulphate/organic and tar ball particles were identified in the sample. In addition, particles with an optical diameter range of 10–30 nm were also observed. They clearly differed from the other particle types, showed homogeneous contrast in the bright-field TEM images, and evaporated within tens of seconds when exposed to the electron beam. They were interpreted as representatives of freshly nucleated particles.

In numerous biological contexts, animal cells need to interact physically with their environment by developing mechanical forces. Among these, traction forces have been well-characterized, but there is a lack of techniques allowing the measurement of the protrusion forces exerted by cells orthogonally to their substrate. We designed an experimental setup to measure the protrusion forces exerted by adherent cells on their substrate. Cells plated on a compliant Formvar sheet deform this substrate and the resulting topography is mapped by atomic force microscopy (AFM) at the nanometer scale. Force values are then extracted from an analysis of the deformation profile based on the geometry of the protrusive cellular structures. Hence, the forces exerted by the individual protruding units of a living cell can be measured over time. This technique will enable the study of force generation and its regulation in the many cellular processes involving protrusion. Here, we describe its application to measure the protrusive forces generated by podosomes formed by human macrophages.

We present a methodology for developing ultra-thin and strong formvar-based membranes with controlled morphologies. Formvar is a thin hydrophilic and oleophilic polymer inert to most chemicals and resistant to radiation. The formvar-based membranes are viable materials as support structures in micro- and macro-scale systems depending on thinness and porosity control. Tunable sub-micron thick porous membranes with 20%-65% porosity were synthesized by controlling the ratios of formvar, glycerol, and chloroform. This synthesis process does not require complex separation or handling methods and allows for the production of strong, thin, and porous formvar-based membranes. An expansive array of these membrane characterizations including chemical compatibility, mechanical responses, wettability, as well as the mathematical simulations as a function of porosity has been presented. The wide range of chemical compatibility allows for membrane applications in various environments, where other polymers would not be suitable. Our formvar-based membranes were found to have an elastic modulus of 7.8 GPa, a surface free energy of 50 mN m-1 and an average thickness of 125 nm. Stochastic model simulations indicate that formvar with the porosity of ∼50% is the optimal membrane formulation, allowing the most material transfer across the membrane while also withstanding the highest simulated pressure loadings before tearing. Development of novel, resilient and versatile membranes with controlled porosity offers a wide range of exciting applications in the fields of nanoscience, microfluidics, and MEMS.

A continuous energy loss measurements of 63 Cu, 28 Si, 27 Al, 24 Mg, 19 F, 16 O and 12 C ions over an energy range of (0.06–0.65) MeV/nucleon through thin polymeric foils (Mylar, Polypropylene and Formvar) were carried out by time of flight spectrometry. The deduced experimental stopping data have been used in order to assess our proposed semi empirical formula. The proposed approach based on the Firsov and Lindhard–Scharff stopping power models is provided for well describing-the electronic stopping power of heavy ions (3 ⩽ Z ζ e factor, which was approximated to be ∼ Z 1 1 / 6 , involved in Lindhard, Scharff and Schiott (LSS) formula has been suitably modified in the light of the available experimental stopping power data. The calculated stopping power values after incorporating, effective charge Z 1 ∗ of moving heavy ions with low velocities ( v ⩽ v 0 Z 1 2 / 3 ) and modified ζ e in LSS formula, have been found to be in close agreement with measured values in various solids targets. A reason of energy loss measurements is to obtain data that help to assess our understanding of the stopping power theories. For this, the obtained results are compared with, LSS calculations, MSTAR and SRIM-2013 predictions code.

Energy loss distributions for (0.5

Measurements are presented of the phase function, P11, and asymmetry parameter, g ,o f five ice clouds created in a laboratory cloud chamber. At � 7 1C, two clouds were created: one comprised entirely of solid columns, and one comprised entirely of hollow columns. Similarly at � 15 1C, two clouds were created: one consisting of solid plates and one consisting of hollow plates. At � 30 1C, only hollow particles could be created within the constraints of the experiment. The resulting cloud at � 30 1C contained short hollow columns and thick hollow plates. During the course of each experiment, the cloud properties were monitored using a Cloud Particle Imager (CPI). In addition to this, ice crystal replicas were created using formvar resin. By examining the replicas under an optical microscope, two different internal structures were identified. The internal and external facets were measured and used to create geometric particle models with realistic internal structures. Theoretical results were calculated using both Ray Tracing (RT) and Ray Tracing with Diffraction on Facets (RTDF). Experimental and theoretical results are compared to assess the impact of internal structure on P 11 and g and the applicability of RT and RTDF for hollow columns. & 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

The energy-loss straggling of 28 Si, 27 Al, 24 Mg, 19 F, 16 O and 12 C partially stripped heavy ions has been determined in Formvar polymeric thin foil over a continuous range of energies 0.1–0.6 MeV/u, by using a powerful method based on the combination of Heavy Ion-Elastic Recoil Detection Analysis (HI-ERDA) technique and Time of Flight (ToF) spectrometer. The obtained energy loss straggling values have been analyzed and compared with the corresponding computed values adopting some widely used energy loss straggling formulations such as, Bohr, Bethe–Livingston and Yang formulas. The aim of such a comparison is to check the reliability and accuracy of the existing energy loss straggling formulations. The experimental results of energy loss straggling of all ions are found to be significantly greater than those predicted by the theories. These differences can be attributed to the charge exchange straggling. This effect has to be taken into account in order to explain the obtained results.

We measured the linear thermal expansion coefficients of amorphous 5–30 nm thick SiN and 17 nm thick Formvar/Carbon (F/C) films using electron diffraction in a transmission electron microscope. Positive thermal expansion coefficient (TEC) was observed in SiN but negative coefficients in the F/C films. In case of amorphous carbon (aC) films, we could not measure TEC because the diffraction radii required several hours to stabilize at a fixed temperature.

We report a facile method for controllable fabrication of high-density silver nanoparticle films with a widely adjustable surface plasmon resonance (SPR) frequency, based on the gas phase cluster beam deposition. On the one hand, we can control the particle size by depositing clusters on silica substrate. Light extinction spectra of the self-assembled Ag nanoparticles with various particle sizes are characterized and show two SPRs, in which a SPR exhibits a redshift from less 400 nm to more than 570 nm with an increase in the particle size, whereas the other shows a slight position shifting. On the other hand, the inter-particle distance of the self-assembled Ag nanoparticles can also be controlled by depositing clusters on silica glass coated with Formvar film, and the SPR wavelength shows a redshift from

We have determined continuous stopping power of heavy ions in thin Formvar foil for 28 Si, 27 Al and 24 Mg ions over an energy range of (0.1–0.5) MeV/nucleon. Heavy Ions Elastic Recoil Detection Analysis (HI-ERDA) technique coupled with time of flight (ToF) spectrometer has been used to measure energy loss of charged particles in this thin absorber. Lindhard, Scharff and Schiott (LSS) theory compared with the corresponding determined stopping values in Formvar, shows significantly large deviations. However, a novel semi empirical expression has been proposed here and tested for better stopping power calculations at low velocity in the ion energy domain of LSS theory for 28 Si, 27 Al and 24 Mg ions crossing thin Formvar foil. The results were compared to the obtained experimental stopping power data, predictions of LSS theory and also to those generated by SRIM-2010 computer code. The obtained results exhibit good agreement with experimental data.

Morphological and optical properties of a polymer film/glass system with laser-implanted Au nanofragments were studied. The polymer films (formvar) were deposited on glass plates by the Langmuir–Blodgett method. The fragmentation of continuous Au films was carried out by a Q-switched YAG:Nd 3+ laser ( λ = 532 μm, t p = 10 ns) at the condition of the surface plasmon-polariton resonance (SPR) and subsequent ballistic transport of Au nanoparticles (NPs) through the air gap and fixation in the polymer film. It is shown that the average size and concentration of the implanted NPs are significantly influenced by the SPR. They were ranged from 40 nm and 6.5 × 10 9 cm −2 up to 350 nm and 5 × 10 7 cm −2 at the resonant and nonresonant cases, respectively. Possible mechanisms of decomposition of the Au film fragments are discussed within the framework of a thermal model.

As found experimentally, macromolecules in the near-surface sections of a film prepared by solvent evaporation from a solution of polyvinylformal in dichloroethane acquired mobility under an electron beam to increase the rate of macromolecular association with the formation of nanosized aggregates by three or more orders of magnitude.

A method was developed to systematically investigate individual aerosol particles collected onto a polyvinyl formal (Formvar)-coated copper grid with scanning electron microscopy. At very mild conditions with a low accelerating voltage of 2 kV and Gentle Beam mode aerosol particles down to 20 nm in diameter can be observed. Subsequent processing of the images with digital image analysis provides size resolved and morphological information (elongation, circularity) on the aerosol particle population. Polystyrene nanospheres in the expected size range of the ambient aerosol particles (20–900 nm in diameter) were used to confirm the accuracy of sizing and determination of morphological parameters. The relative standard deviation of the diameters of the spheres was better than ±10% for sizes larger than 40 nm and ±18% for 21 nm particles compared to the manufacturer's certificate. Atmospheric particles were collected during an icebreaker expedition to the high Arctic (north of 80°) in the summer of 2008. Two samples collected during two different meteorological regimes were analyzed. Their size distributions were compared with simultaneously collected size distributions from a Twin Differential Mobility Particle Sizer, which confirmed that a representative fraction of the aerosol particles was imaged under the electron microscope. The size distributions obtained by scanning electron microscopy showed good agreement with the Twin Differential Mobility Sizer in the Aitken mode, whereas in the accumulation mode the size determination was critically dependent on the contrast of the aerosol with the Formvar-coated copper grid. The morphological properties (elongation, circularity) changed with the number of days the air masses spent over the pack-ice area north of 80° before the aerosol particles were collected at the position of the icebreaker and are thus an appropriate measure to characterize transformation processes of ambient aerosol particles.

Metal shadowing of bacteria, viruses, isolated molecules, and macromolecular assemblies is another high-resolution method for observing the ultrastructure of biological specimens. The actual procedure for producing a metal shadow is relatively simple; a heavy metal is evaporated from a source at an oblique angle to the specimen. The metal atoms pile up on the surfaces that face the source, but the surfaces away from the source are shielded and receive little metal deposit, creating a "shadow." However, the process of producing biological specimens that are suitable for metal shadowing can be very complex. There are a whole host of specimen preparation techniques that can precede metal shadowing, and all provide superior preservation in comparison to air drying, a required step in negative staining procedures. The physical forces present during air drying (i.e., surface tension of the water-air interface) will literally crush most biological specimens as they dry. In this chapter I explain the development of and procedures for the production of biological specimens from macromolecular assemblies (e.g., DNA and RNA), purified isolated molecules (e.g., proteins), and isolated viruses and bacteria preparations suitable for metal shadowing. A variation on this basic technique is to rotate the specimen during the metal deposition to produce a high-resolution three-dimensional rendering of the specimen.

Stopping power and energy loss straggling data for protons (1H+) and alpha particles (4He+) crossing Formvar thin polymeric foils (thickness of ∼0.3 μm) have been measured in the energy range (0.3–2.7) MeV by using the indirect transmission technique. The determined stopping power data were compared to SRIM-2010, PSTAR or ASTAR calculation codes and then analyzed in term of the modified Bethe–Bloch theory to extract the target mean excitation and ionization potential 〈I〉. A resulting value of 〈I〉≈(69.2±1.8) eV was deduced from proton stopping data. The measured straggling data were corrected from surface roughness effects due to target thickness inhomogeneity observed by the atomic force microscopy (AFM) technique. The obtained data were then compared to derived straggling values by Bohr's and Bethe–Livingston's classical theories or by Yang's empirical formula. A deviation of ∼40%–80% from the Bohr's straggling value has been observed for all reported energies, suggesting that the Bohr theory cannot be correctly applied to describe the electronic energy loss straggling process with the used low thickness of Formvar foil. The inner-shell contribution of target electrons to energy loss process is also advanced to explain the observed deviation from experiment in case of He+ ions. Finally, the reliability of Bragg's additivity rule was discussed in case of stopping power and straggling results.

Hydrophilicity/hydrophobicity of the surfaces of plasma-polymerized naphthalene film (Super Support Film, Nisshin EM Co. Ltd., Tokyo), carbon and formvar support films, and copper and nickel grids were quantitatively estimated by contact angles measured from diameters and heights of water droplets placed on various specimens. With treatment of glow discharge, the surfaces of plasma-polymerized naphthalene and carbon support films became fully hydrophilic in 20 s. They remained hydrophilic for 6 h. The surfaces of copper and nickel grids became fully hydrophilic with 60 s of glow discharge treatment. They remained hydrophilic for only 1 h. This information is useful for negative staining, ultrathin sectioning and rapid freezing of biological specimens using the sandwich method.

For the first time, falling ice crystals were collected on glass slides covered with a thin layer of 2% formvar in chloroform at the Dome Concordia site (Dome C), Antarctica. Samplings were performed in the framework of the 27th Italian Antarctica expedition of the Italian National Program for Research in Antarctica in the period 21 February-6 August 2012. Events of clear-sky precipitations and precipitations from clouds were considered and the replicas obtained were examined under Scanning Electron Microscope (SEM). Several shapes of ice crystals were identified, including "diamond dust" (plates, pyramids, hollow and solid columns), and crystal aggregates varying in complexity. Single events often contained both small (10 mu m to 50 mu m) and large (hundreds of microns) crystals, suggesting that crystals can form simultaneously near the ground (height of a few hundred metres) and at higher layers (height of thousands of metres). Images of sampled crystal replicas showed that single bullets are not produced separately, but by the disintegration of combinations of bullets. Rimed ice crystals were absent in the Dome C samples, i.e. the only mode of crystal growth was water vapour diffusion. On considering the aerosol in the sampled crystals, we reached the conclusion that inertial impaction, interception and Brownian motion were insufficient to explain the scavenged aerosol. We therefore presume that phoretic forces play a role in scavenging during the crystal growth process. (C) 2015 Elsevier B.V. All rights reserved.

The stopping forces of formvar, polysulfone, polyimide, and vyns for 0.1–0.7 MeV/u 35 Cl ions, 0.1–0.4 MeV/u 79 Br ions, and 0.1–0.2 MeV/u 127 I ions have been measured with the transmission technique and thin foil targets. A modified time of flight elastic recoil detection analysis setup and simulation of experimental slowing down energy spectra were employed for obtaining stopping force curves over a continuous range of energies. The results are compared with predictions of widely used parameterization models for the stopping force.

Laboratory experiments were performed to determine the effect of electrical charges transferred on droplets by electrical discharges on their growth by collision and coalescence. A twin cloud chamber was built inside a large cold room and was filled with cloudy air. One chamber was used as the control chamber and, therefore, was left unperturbed. On the other hand, in an experimental chamber, electrical discharges were produced. Droplets grow during a free fall of 1 m, and the droplet spectrum was sampled by microscope slides covered in Formvar. The experimental arrangement could also measure charge on individual drops between 325 and 415 μm in diameter by using small induction rings. After comparing the spectra from both chambers, a shift towards larger sizes was observed in the cloud that sustained electrical discharge. Also, by measuring the charge on the droplets, it could be observed that the electrical discharge transferred charges of both signs. Discussions about the relevance for cloud seeding and fog elimination are carried out.

Polyvinyl formal (Formvar®) foils were irradiated with 5.4 MeV/u Au ions and analysed in-situ by residual gas analysis and infrared spectroscopy. The experiment was performed at the new materials-research beamline (M-branch) at the universal linear accelerator of the GSI Helmholtz Centre in Darmstadt (Germany). Simultaneously analysing outgassing fragments and changes within the irradiated polymer film allows monitoring details of the degradation process. Ion-induced degradation of polyvinyl formal is characterized by fragmentation of side chains of the polymer backbone. The infrared spectra show the formation of unsaturated hydrocarbons and ketones. A possible degradation mechanism is proposed including the production of enols as reported earlier for degradation of polyvinyl alcohol exposed to gamma radiation.

Alpha spectrometry is an extremely useful and sensitive for detection of alpha-emitting nuclides. Contamination of the silicon detectors for low-level alpha spectrometry by recoil nuclides is a serious problem in the measurement of alpha emitters decaying to daughter nuclides with short half-lives. This unwanted contamination leads to decreased measurement sensitivity causing a degradation of the limit of detection. The simplest method to prevent this radioactive contamination of detector is to use a catcher film between the alpha source and the detector. In this work we describe the obtaining of the thin formvar films as stopper foils for recoil nuclei and we investigated the influence of these films on alpha spectrometry parameters, as energy shift (~30 keV) and resolution (~7%). No significant deterioration of the alpha spectrometry parameters was observed when using thin formvar films. Using the ASTAR web databases, which calculate stopping powers for alpha particles, the thickness of formvar films was estimated to be about 5.355 × 10−5 g/cm2. The measurements were performed with an ORTEC SOLOIST alpha spectrometer with PIPS detector.

The centering of an ignition target capsule strongly depends on high-quality “tents” with closely matched mechanical properties. The relevant properties are tent stiffness and relaxation behavior. Tent stiffness is matched by choosing tents of equal thickness. Here, we describe recent advances in tent fabrication that have increased the quality and production rate of tents. The most significant improvement comes from the use of a meniscus coater to produce Formvar tents of high uniformity and with good control of tent thickness and good yield. Other improvements include a switch to silicon wafers as deposition substrate and standardized tent holders. The improvements have resulted in a sixfold increase of the production rate while increasing the yield by a factor of 2, despite tighter quality control.

A 0.88 T Nb-Ti superconducting undulator with a period length of 16 mm and a period number of 50 is proposed recently at SSRF. The magnetic field simulation shows that it is possible to obtain a peak field of 0.88 T on the beam axis at a magnetic gap of 8 mm. And two coil formers of five periods have been machined from SAE1018 stainless steel and sputtered with thin TiO2 film for insulation. One coil former has been wound with copper wires and impregnated with epoxy resins, and the other has been wound using Nb-Ti/Cu wires, impregnated and tested. The dimension of the grooves of the coil windings is 5 mm × 12 mm. Formvar insulated Nb-Ti/Cu superconducting wires with a diameter of 0.6 mm are used to wind the coils. Experimental results show that the critical current of the coil could reach as high as 312 A at 2.5 T, 88% of the critical current of short Nb-Ti/Cu samples from the same bunch, which means the coil winding and impregnation crafts employed could meet the requirement of the 0.88 T Nb-Ti superconducting undulator.

A novel method of transferring large-area graphene sheets onto a variety of substrates using Formvar (polyvinyl formal) is presented. Due to the ease at which formvar can be dissolved in chloroform this method allows for a consistent, a clean, and a more rapid transfer than other techniques including the PMMA assisted one. This novel transfer method is demonstrated by transferring large-area graphene onto a range of substrates including commercial TEM grids, silicon dioxide and glass. Raman spectroscopy was used to confirm the presence of graphene and characterize the morphological properties of the large-area sheets. SEM and AFM analyses demonstrated the effectiveness of our rapid transfer technique for clean crystalline large-area graphene sheets. The removal of the sacrificial polymer was found to be one to two orders of magnitude faster than PMMA methods. Ultimately this facile transfer technique offers new opportunities for a wide range of applications for large-area graphene through the utilization of a new sacrificial polymer.