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The technology progress and increasing high density demand have driven the nonvolatile memory devices into nanometer scale region. There is an urgent need of new materials to address the high programming voltage and current leakage problems in the current flash memory devices. As one of the most important nanomaterials with excellent mechanical and electronic properties, carbon nanotube has been explored for various nonvolatile memory applications. While earlier proposals of "bucky shuttle" memories and nanoelectromechanical memories remain as concepts due to fabrication difficulty, recent studies have experimentally demonstrated various prototypes of nonvolatile memory cells based on nanotube field-effect-transistor and discrete charge storage bits, which include nano-floating gate memory cells using metal nanocrystals, oxide-nitride-oxide memory stack, and more simpler trap-in-oxide memory devices. Despite of the very limited research results, distinct advantages of high charging efficiency at low operation voltage has been demonstrated. Single-electron charging effect has been observed in the nanotube memory device with quantum dot floating gates. The good memory performance even with primitive memory cells is attributed to the excellent electrostatic coupling of the unique one-dimensional nanotube channel with the floating gate and the control gate, which gives extraordinary charge sensibility and high current injection efficiency. Further improvement is expected on the retention time at room temperature and programming speed if the most advanced fabrication technology were used to make the nanotube based memory cells.

Nanocrystalline CO₃O₄ particles were successfully synthesized by hydrothermal method under pulsed magnetic field. The effect of magnetic field and aging time on the morphology and microstructure were examined. Different morphologies were observed from SEM images for the samples fabricated with or without pulsed magnetic field. The pulsed magnetic field made CO₃O₄ sphere compact and more smooth surface. The hollow sphere morphology and refined grain of CO₃O₄ were formed after aging process.

Amorphous zirconium oxide (a-ZrO₂) thin films were prepared onto fuzzed quartz substrates by ion beam sputtering deposition (IBSD) method in (Ar +O₂) gas mixture. Optical parameters of the films were evaluated by laser ellipsometry (λ = 632.8 nm) and optical transmission measurements. Structural parameters were studied by XRD measurements. Variation of refractive index and film thickness have been defined as a function of time of high-temperature annealing at T = 900°C. Formation of monoclinic zirconium oxide (m-ZrO₂) nanocrystals with diameter of ~60 nm embedded into a-ZrO₂ matrix has been found by XRD analysis after long-time annealing.

A typical nitrogen doped spherical SiC nanocrystal with a diameter of 1.2 nm (Si₄₃C₄₄H₇₆) using linear combination atomic orbital (LCAO) in combination with pseudopotential density functional calculation have been studied. Our selected SiC nanocrystal has been modeled taking all the cubic bulk SiC atoms contained within a sphere of a given radius and terminating the surface dangling bonds with hydrogen atoms. We have examined nine possible situations in which nitrogen has a high probability for replacement in the lattice or placed between atoms in the nanocrystal. We have found that the silicone can substitute with a nitrogen atom in each layer as the constructed nanocrystals remain thermodynamically stable. Also the nitrogen atom can be placed between the free atomic spaces as the more thermodynamically stable position of the nitrogen is between the topmost layers. Also the optical absorption and refractive index energy dispersions of the pure and various stable doped SiC nanocrystals were studied.

LiFePO₄ nanocrystals were synthesized in various polyol media without any further post-heat treatment. The LiFePO₄ samples synthesized using three different polyol media namely, diethylene glycol (DEG), triethylene glycol (TEG), and tetraethylene glycol (TTEG), exhibited plate and rod-shaped structures with average sizes of 50–500 nm. The X-ray diffraction (XRD) patterns were indexed on the basis of an olivine structure (space group: Pnma). The samples prepared in DEG, TEG, and TTEG polyol media showed reversible capacities of 123, 155, and 166 mAh/g, respectively, at current density of 0.1 mA/cm² with no capacity fading and exhibited excellent capacity retention up to the 50th cycle. In particular, the samples showed excellent performances at high rates of 30 and 60 C with high capacity retention. It is assumed that the nanometer size materials (~50 nm) possessing a highly crystalline nature may generate improved performance at high rate current densities.

A novel procedure to fabricate nanoarchitectures of crystalline titania hollow shells was developed by using assembled latex particles as templates. Latex particles were assembled on the surface of solid substrates and covered with ultrathin titania films by the surface sol–gel process. When the titania-covered latex particle was subjected to oxygen plasma treatment, hollow titania spheres were formed at the original site of particle deposition. Following calcination of the amorphous, titania hollow shells induced their crystallization to titania nanocrystals (anatase).

Monodispersed DAST nanocrystals have almost been successfully fabricated by means of the inverse reprecipitation method. By employing AC electric field, high electric field of above ca. 1.0 kVcm^-1 could be applied to polar DAST nanocrystals dispersed in decahydronaphthalene, so as to avoid electrophoresis of nanocrystals under DC electric field. The response of DAST nanocrystal dispersion to applied AC electric field was analyzed phenomenologically by fitting Langevin function, which provided a large permanent dipole moment of DAST nanocrystal. In addition, we have succeeded in in situ observation of AC electric-field-induced orientational motion of DAST crystals by using an optical microscope. The present DAST nanocrystal dispersion system will be expected as an optical device like display monitor.

Photoluminescent properties of CdSe/ZnS nanocrystals (quantum dots, QDs) in complexes with elongated gold nanoparticles was found to be dependent on the effective refractive index of the medium. It has been experimentally shown that changes in the refractive index make possible to increase the photoluminescence intensity by several times.

A series of cadmium telluride (CdTe) nanocrystals were synthesized by a modified organometallic synthesis method at various reaction temperatures ranging from 130 to 250°C. In this method, octadecylamine (ODA) was introduced as an additional coordinating component to the mixture of trioctylphosphine oxide (TOPO) and trioctylphosphine (TOP). CdO was used as a precursor. The prepared CdTe nanocrystals were studied by the absorption and emission spectra as well as the powder X-ray diffraction (XRD) patterns. The result shows that besides the traditional continuous-growth mode observed frequently at relatively high reaction temperature, a discontinuous-growth mode was confirmed at the initial growth stage of CdTe nanocrystals, arising from the change of the absorption spectra of CdTe nanocrystals with the reaction time at relatively low reaction temperature. The structures of CdTe nanocrystals, e.g., the cubic zinc blende structure at 160°C and the hexagonal wurtzite structure at 250°C, were characterized by XRD.

Colloidal CdSe nanocrystals (NCs) were etched after Se/TBP and Zinc stearate/ODE were injected into the mixture of as-prepared CdSe NCs and Copper (II) acetate in ODE solvent. Spectroscopic and structural investigations demonstrate the etching process. Along with the etching time, both the absorption and photoluminescence (PL) spectra of etched NCs showed blue-shift while the transmission electron microscopy (TEM) images indicated that the size of the NCs became from 5.6nm to 2.6nm. X-ray diffraction (XRD) patterns suggested that no other clusters or core/shell NCs were formed in the etching process and inductively coupled plasma (ICP) data demonstrated that only selenium and cadmium comprised the etched NCs. Electronic paramagnetic resonance (EPR) spectra indicated the deoxidization of Cu${}^{2+}$ ions and suggested the etching mechanism through cation exchange process.

Nanostructured LiFePO₄ is appealing cathode material for rechargeable lithium batteries. Herein, however, we report the intriguing anode properties of carbon coated LiFePO₄ nanocrystals. In the potential range of 0–3.0 V, the LiFePO₄ nanocrystal electrodes afford high reversible capacity of 373 mAhg${}^{-1}$ at a current rate of 0.05 Ag${}^{-1}$ and retains 239 mAhg${}^{-1}$ at a much higher rate of 1.25 Ag${}^{-1}$. In addition, it is capable of sustaining 1000 cycles at 1.25 Ag${}^{-1}$ without any capacity fading. Such superior properties indicate that nanostructured LiFePO₄ could also be promising anode for rechargeable battery applications.

PbS nanocrystals with octahedron shape are synthesized by a low temperature approach with presence of cation/anion surfactants in aqueous solution. CdS quantum dot sensitized solar cells (QDSSCs) based on these novel octahedron shaped PbS counter electrodes (CEs) are fabricated for the first time, achieving PCE of 1.54%. It is observed that the octahedron shaped PbS CE shows higher electrocatalytic activity compared with the Pt CE, indicating that the PbS nanocrystals with a uniformly distributed size is a superior candidate as CEs for QDSSCs application. This work may provide new route for preparing PbS from aqueous solvent medium through a simple synthesis route.

Mn K-edge absorption measurements were carried out on α-Mn₂O₃ and Mn₃O₄ nanocrystals supported on a mesoporous silica, SBA-15. The X-ray absorption near edge structure (XANES) spectra demonstrate the existence of the oxidation states of Mn (2+ and 3+) in Mn₃O₄ and Mn (3+) in Mn₂O₃, those ions were present in different octahedral environments. Meanwhile, XANES data demonstrate that some Mn atoms that are bonding to the inner wall of the channels as isolated species, may exist as Mn⁴⁺ in Mn₂O₃/SBA-15. In addition, the structure, texture, and electronic properties of nanocomposites were also studied using various characterization techniques including X-ray diffraction (XRD) and laser Raman spectroscopy (LRS). The formation of the hausmannite Mn₃O₄ and bixbyite Mn₂O₃ structures has been confirmed clearly by XRD. The prepared nanocomposites of MnO_x showed significant catalytic activity towards CO oxidation below 523 K.

The changing of materials surface properties method always was taken into improving the fatigue strength. In this paper, an ultrasonic nanocrystal surface modification(UNSM) technique was used on the SUS 304 stainless steel to form a nanostructured surface layer with different static load(70N, 90N, 110N, 130N) and the vibration strike number was about 20,000times/mm². The untreated and different condition specimens fatigue strength was all tested by a dual-spindle rotating bending fatigue test machine. SPring-8(a large synchrotron radiation facility) was used to test the surface nanocrystallization components. The X-ray diffraction (XRD), the scanning electron microscopy (SEM), optical microscope and a micro-Vickers hardness tester (MVK-E3, Akashi) were separately used to get the surface residual stresses, fracture surface after fatigue testing, metallographic structure and the microhardness of the nanostructured surface layer. The result showed that martensite transformation took place on the surface of specimens, the surface residual stresses had only a small increase and some cracks occurred between the martensite layer and the austenite layer, but the fatigue strength of 90N improved 81%.

Going down the particle size to nanodomain opens up innovative allies to expedite the physical and chemical properties of materials, and in turn, facilitates the manipulation of their catalytic propensity. Herein, we provide a succinct perspective of the wide spectrum of nanoparticles (NPs) in catalysis highlighting the underlying chemistry of different aspects, the introspective thread connecting them, and the ways to devise operando algorithms for exploiting such inter-connected systems. Following an introductory section discussing the generic miens of NPs, we went on to discuss the role of nanocrystals, especially various crystal facets and morphological anomalies in catalysis. The electronic shuttling involved in these catalysis vis-à-vis surface plasmon effect, Mott–Schottky contact, and Z-scheme systems, all in the nanodomain, was then explained. Following this, we introduced the concept of “Soft Matter” and “Active Matter”, essentially the ones exploiting previously discussed chemistry, and explained the role of their in situ morphological precedence and stimuli-induced motility in catalysis. Finally, the emerging concept of Operando Systems Chemistry Algorithm (OSCA) was instituted discussing the devising strategies of tandem compartmentalized chemical arrays as individual algorithm analogs to sequentially impact the properties of aforementioned soft and active matters for targeted catalytic assays.

The technology progress and increasing high density demand have driven the nonvolatile memory devices into nanometer scale region. There is an urgent need of new materials to address the high programming voltage and current leakage problems in the current flash memory devices. As one of the most important nanomaterials with excellent mechanical and electronic properties, carbon nanotube has been explored for various nonvolatile memory applications. While earlier proposals of “bucky shuttle” memories and nanoelectromechanical memories remain as concepts due to fabrication difficulty, recent studies have experimentally demonstrated various prototypes of nonvolatile memory cells based on nanotube field-effect-transistor and discrete charge storage bits, which include nano-floating gate memory cells using metal nanocrystals, oxide-nitride-oxide memory stack, and more simpler trap-in-oxide memory devices. Despite of the very limited research results, distinct advantages of high charging efficiency at low operation voltage has been demonstrated. Single-electron charging effect has been observed in the nanotube memory device with quantum dot floating gates. The good memory performance even with primitive memory cells is attributed to the excellent electrostatic coupling of the unique one-dimensional nanotube channel with the floating gate and the control gate, which gives extraordinary charge sensibility and high current injection efficiency. Further improvement is expected on the retention time at room temperature and programming speed if the most advanced fabrication technology were used to make the nanotube based memory cells.

We demonstrate the potential of the electronic-structure methods developed recently for the calculation of optical properties of solids. The many-body effects, i.e. quasiparticles, excitons and local fields, are fully taken into account by solution of the combined Dyson and Bethe-Salpeter equations. The principal effects but also the validity of the used approximations are discussed for bulk semiconductors such as Si and prototypical molecules such as SiH₄. The extension of the theory to systems with spin ordering or strong confinement is demonstrated. Their influence on the many-body effects is discussed for the paradigmatic insulator MnO and a silicon nanocrystal.

A novel procedure to fabricate nanoarchitectures of crystalline titania hollow shells was developed by using assembled latex particles as templates. Latex particles were assembled on the surface of solid substrates and covered with ultrathin titania films by the surface sol–gel process. When the titania-covered latex particle was subjected to oxygen plasma treatment, hollow titania spheres were formed at the original site of particle deposition. Following calcination of the amorphous, titania hollow shells induced their crystallization to titania nanocrystals (anatase).

Monodispersed DAST nanocrystals have almost been successfully fabricated by means of the inverse reprecipitation method. By employing AC electric field, high electric field of above ca. 1.0 kVcm^-1 could be applied to polar DAST nanocrystals dispersed in decahydronaphthalene, so as to avoid electrophoresis of nanocrystals under DC electric field. The response of DAST nanocrystal dispersion to applied AC electric field was analyzed phenomenologically by fitting Langevin function, which provided a large permanent dipole moment of DAST nanocrystal. In addition, we have succeeded in in situ observation of AC electric-field-induced orientational motion of DAST crystals by using an optical microscope. The present DAST nanocrystal dispersion system will be expected as an optical device like display monitor.

[Purpose] This study aimed to study the kinetic aggregation of urine crystallites with different sizes in the urines of calcium oxalate (CaOx) calculi patients and healthy controls. [Methods] We studied the property changes in crystallites with different sizes by nanoparticle size analysis and transmission electron microscopy (TEM) in two types of urine filtered through a microporous membrane of 0.22, 0.45, 1.2, 3.0, and 8 μm. [Results] The measured Zeta potential in the two types of urine crystallites and polydispersity index showed that the urine crystallites of the patients were rapidly aggregated, whereas those of the controls were only slightly or slowly aggregated with increased placement time from 1 h to 8 h. The small-sized urine crystallites were easy to aggregate than the large-sized ones. [Conclusion] The urinary system of calculi patients is unstable and very susceptible to urine crystallite aggregation. The rapid aggregation of urine crystallites may be an important factor affecting the growth of crystallites in CaOx calculi patients.