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The thermal warpage of nitrogen-doped Czochralski (NCZ) silicon wafers affected by preannealing was investigated. After preannealing at 1000 °C for 6 h, the warpage of the NCZ silicon wafers was suppressed during subsequently thermal warping tests, while the silicon wafers grown under an argon ambient (ACZ) showed an increase in warpage. Nitrogen was considered to be very effective to increase the mechanical strength of silicon wafers because of the formation of nitrogen-oxygen clusters with smaller sizes. After preannealing at 1000 °C for 16 h, both ACZ and NCZ silicon wafers showed a large increase of warpage due to the large amount of oxygen precipitation.

A 300 mm, p-type, 〈1 0 0〉-oriented nitrogen-doped Czochralski (NCZ) silicon crystal was grown in a Keyex MCZ 150 crystal puller equipped with cusp magnetic field. In order to dope nitrogen into the crystal, the primary protection gas of argon was mixed with high-purity nitrogen gas at a flow rate ratio of 10:1. Due to the long time growth of crystal, any perturbation due to the SiO and cristobalite particles at the crystal/melt interface would generate dislocation in the crystal. In order to avoid this ‘disaster’ during the crystal growth, a thermal shield in connection with a protection gas director was used, thereby generating a sweeping flow over the melt to drive the SiO and cristobalite particles out of the crystal/melt interface. The oxygen precipitation behavior of a near-seed-end wafer subjected to 800 °C/8 h+1000 °C/16 h was investigated. It was found that oxygen precipitation within the P-band was stronger than that in the region outside of the P-band, which is generally not the case for the conventional Czochralski (CZ) wafer with P-band. Based on this result, it is deduced that the grown-in oxygen precipitates existing in the P-band are relatively smaller in size but with higher density compared to those in the CZ crystal.

A U-shaped optical fiber sensing system designed to measure the refractive index of liquid had been proposed. The sensing mechanism of U-shaped optical fiber was discussed. A general single-mode fiber was bent into U-shaped and partially cladding of U-shaped fiber was corroded by HF acid buffer solution. Powers of different diameters of U-shaped fibers had been measured by many experiments. The results showed that the diameter of U-shaped fiber cladding 40 μm and the diameter of U-shaped was 1 cm were suitable to measure liquid refractive index. Then, this U-shaped optical fiber was immersed in liquid, such as pure water, ethanol, acetone and isopropanol, respectively. The evanescent field of the U-shaped fiber should be modulated by the liquid. The optical signal in the U-shaped fiber was measured with the optical spectrum analyzers(OSA). Finally, the experimental results were analyzed, and the spectra in the air was selected as a reference. The relative intensity was obtained for the different liquid. These results showed that the relative intensity of the liquid had a good linear relationship. This sensing device could accurately demarcate refractive index of liquid. It is simple, low cost, and it can also be applied in measuring the level of liquid.

The formation behavior of donors associated with oxygen in nitrogen‐doped and undoped Czochralski silicon has been investigated by means of electrical and infrared measurements at low temperatures (8 K). It is found that donors are not generated in N‐doped silicon annealed at 650 °C up to 100 h. We have also studied the effect of preannealing at 450 and 1050 °C on the formation of donors in the N‐doped silicon. The 450 °C preannealing enhances the formation of donors in the subsequent annealing at 650 °C, while the 1050 °C preannealing has no effect. The donor concentration increases at 650 °C with the 450 °C preannealing time. The formation of nitrogen–oxygen complexes in the N‐doped silicon is believed to suppress the generation of nuclei of donors, and, consequently, the formation of donors.

The effect of oxygen precipitates and induced dislocations on oxidation-induced stacking faults (OSFs) in nitrogen-doped Czochralski (NCZ) silicon has been investigated. Both CZ and NCZ wafers were annealed at 800°C and 1000°C for 225h with or without a post-treatment at 1200°C for 8h, and then were totally oxidized at 1150°C. It was found that after oxidization, few OSFs generated in the NCZ silicon subjected to the annealing at 800 and 1000°C, while larger numbers of OSFs in the CZ silicon. However, if the post-treatment at 1200°C was employed prior to oxidization, OSFs density in the NCZ silicon was almost similar to that in the CZ silicon. It is considered that the high density of oxygen precipitates and induced dislocations formed in NCZ silicon can absorb the self-interstitial silicon atoms so that the generation of OSFs is inhibited. After the postannealing, most dislocations shrank and dissolved with the dissolution of oxygen precipitates in the NCZ silicon so as to induce the same amount of OSFs ...

The generation process of silver chloride was studied using dynamic speckle methods including speckle size measurement and speckle contrast measurement. The quantity and size changes of the sedimentation particles in the illuminating region were investigated and analyzed.

The infrared optical absorption of nitrogen–oxygen complex in Czochralski (CZ) silicon measured by a Fourier Transmission Infrared Spectroscope (FTIR) has been studied. The CZ silicon samples grown in N–O complex were annealed in the temperature range of 450–1150°C for 10, 20 and 30 min. It was found that the variation of the optical lines measured in the middle infrared range and that in the far infrared range had the same tendency during annealing. The relations of the absorption lines in the middle and far infrared range were built. It is considered that the absorption lines in both infrared ranges come from same defects in silicon.

The process of thermal denaturation of the albumin was investigated using dynamic speckle method based on wavelet entropy and analyzed by light scattering theory. In experiments, the dynamic speckle patterns sequences generated by albumin colloid during denaturing were acquired using a CCD camera. By analyzing the variations of wavelet entropy values of the THSPs (the time history of speckle patterns), the thermal denaturation process of albumin could be divided into two stages. At former heating process, the values of wavelet entropy were bigger; correspondingly, the protein particles were aggregated and flocculated quickly. Conversely, at latter heating process, the wavelet entropy values decreased drastically, which meant there was slow aggregation. According to those, the movement properties of the protein molecule ensemble were analyzed during thermal denaturation of the albumin. The results show that this method is effective to analyze the process of movement and aggregation of protein molecules quantitatively. The experiment proved that this method is an useful tool to investigate the particles motion in solution.

The stress impact on the switching properties of Nd- and La-doped ${\mathrm{Bi}}_{4}{\mathrm{Ti}}_{3}{\mathrm{O}}_{12}$ films were investigated. When the electric field $E$ was kept constant, the net-switched charge $Q$ increased with the stress changing from maximum compression to maximum tension, while the switching time ${t}_{\mathrm{s}}$ increased with increasing both compressive and tensile stress. When $E$ was variable, the variation of $Q(E)$ got enhanced, while that of ${t}_{\mathrm{s}}(E)$ got weakened under both compressive and tensile stress. These could be well explained by stress-induced reorientation of domains instead of strain-polarization coupling, which is further confirmed by Landau-Ginzburg calculations and x-ray-diffraction measurements.

Effect of nitrogen–oxygen (N–O) complexes on electrical properties of nitrogen‐rich Czochralski (CZ) silicon grown in a nitrogen atmosphere has been investigated during annealing in the temperature range from 650 to 1000 °C. Electrical and low temperature (8 K) Fourier transmission infrared spectrometer (FTIR) measurements point out that the carrier concentration of the nitrogen‐rich silicon varies with the annealing time and temperature, which is due to the formation and elimination of the N–O complexes acting as shallow thermal donors. After the N–O complexes are eliminated by annealing above 900 °C the carrier concentration of the nitrogen‐rich silicon is stabilized. It is suggested that the N–O complexes attract more oxygen atoms to form new electrically inactive N–O clusters, and lose their electrical activity.

Study objective: To develop a self administered Chinese (mainland) version of the Short-Form Health Survey (SF-36) for use in health related quality of life measurements in China. Design: A three stage protocol was followed including translation, tests of scaling construction and scoring assumptions, validation, and normalisation. Setting: 1000 households in 18 communities of Hangzhou. Participants: 1688 respondents recruited by multi-stage mixed sampling. Main results: The assumption of equal intervals was violated for the vitality and mental health scales. The recoded item values were used to calculate scale scores. The clustering and ordering of item means was the same as that of the source and other two Chinese versions. The items in each scale had similar standard deviations except those in the physical functioning, boduily pain, social functioning scales. The item hypothesised scale correlations were identical for all except the social functioning and vitality scales. Convergent validity and discriminant validity were satisfactory for all except the social functioning scale. Cronbach's α coefficients ranged from 0.72 to 0.88 except 0.39 for the social functioning scale and 0.66 for the vitality scale. Two weeks test-retest reliability coefficients ranged from 0.66 to 0.94. Factor analysis identified two principal components explaining 56.3% of the total variance. The Chinese SF-36 could distinguish known groups. Conclusions: This study suggested that the Chinese (mainland) version of the SF-36 functioned in the general population of Hangzhou, China quite similarly to the original American population tested. Caution is recommended in the interpretation of the social functioning and vitality scales pending further studies.

The LiP infinite double-helix chain gives us the unique opportunity to investigate the double-helix structure at atomic level. Based on density-functional theory, we investigate the characteristic vibrational modes of this peculiar structure. Differently from single-wall carbon nanotubes, a dipole mode in LiP gives rise to high infrared intensity. Owing to the peculiar double-helix structure of LiP, the frequency of the out-of-phase radical breathing mode is lower than that of the in-phase one. It is similar to the condition of DNA. Furthermore, the out-of-phase breathing mode in LiP, instead of the in-phase one, has the highest Raman intensity. Most importantly, our finding is generally applicable to other double-helix structures. Copyright (C) EPLA, 2014

Two Czochralski (CZ) silicon ingots, named NCZ and ACZ silicon, were grown under the same procedure in nitrogen and an argon atmosphere respectively. The experiments reveal that nitrogen was doped into the silicon ingot and N-O complexes were generated during the crystal growth, while it was grown in a nitrogen atmosphere. The nitrogen concentration profile in the NCZ silicon ingot indicates that the nitrogen concentration in the wafer edges was less than that in the center. It is also found that the as-grown oxygen-thermal donors were almost the same. Furthermore, it is discovered that the profile of phosphorus concentration in NCZ silicon was also the same as that in ACZ silicon. It is considered that compared with argon atmosphere, nitrogen atmosphere ha no influence on the evaporation rates of phosphorus from melting silicon.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The nitrogen‐doped Czochralski (CZ) silicon crystals were grown in a nitrogen atmosphere under reduced pressure. The results show that the resistivity of n‐type N‐doped silicon increases rapidly with annealing time above 700 °C, but that of p‐type N‐doped CZ silicon decreases rapidly under the same conditions. It is suggested that thermal acceptors (TA) are formed in N‐doped silicon. The concentration of thermal acceptor can reach to 1×1014 atom/cm3. The higher the annealing temperature, the longer the time for the maximum thermal acceptor concentration to appear. Nitrogen and oxygen impurities play important roles for generating the thermal acceptor. It is postulated that the thermal acceptor is a kind of Si‐O‐N complex.

A novel structure of anatase TiO2, nanocone-like TiO2 (TiO2-NC), is successfully prepared by a simple liquid-phase deposition method and is used as an anode material. The morphology and spatial arrangement of the TiO2-NC greatly affects the lithium storage, and TiO2-NC achieves a sustained high lithium storage performance (254.7 mA h g−1, corresponding to Li0.76TiO2) by assembling the TiO2-NC into ordered spherical shells. The structural analysis shows that exposed {001} facets of nanosized TiO2-NC help to increase the surface area as well as shorten the diffusion path of lithium transport. Moreover, an ordered arrangement of the TiO2-NC with a channel structure can further increase the surface area and improve the diffusion of the electrolyte, hence enhancing the lithium storage. Electrochemical tests indicate that the bulk intercalation of lithium was accompanied by the phenomenon of interfacial lithium storage in the TiO2-NC. In addition, the polarization of the TiO2-NC hollow spheres is effectively inhibited due to the ordered structure providing comfortable channels for the ionic and electronic diffusion, which imparts improved rate performance.

Pr-doped SrTiO3 ceramics were fabricated by the conventional solid-state reaction method. Pr-doping greatly decreased the lattice parameters and the average grain size of SrTiO3 ceramics sample. Two thermally activated dielectric relaxations were found for the low- and high-temperature relaxations, respectively. By means of a detailed analysis, the low-temperature relaxation was ascribed to the electric hopping between Pr3+ and Pr4+ induced by the Pr-doping, and the origin of the high-temperature relaxation was changed from oxygen vacancies to the polar nanoregions with the increase of Pr content.

Strontium titanate films with high a-axis-orientation [a(100) = 94.1%] were deposited on (111) Pt/Ti/SiO2/Si substrates by the metal organic deposition process. X-ray diffraction shows that the degree of a-axis orientation increases with increasing annealing temperature. It is found that the dielectric properties are improved by a higher annealing temperature, while the leakage currents are also enhanced, and the possible causes of temperature dependence are discussed.

Perovskite BiFeO3 films with various thicknesses were prepared on Pt/Ti/SiO2/Si substrates by metal organic decomposition method. It was found that, with the film thickness increasing from 35 to 120 nm, the grain and ferroelectric domain size slightly increased, while the saturation magnetization Ms abruptly decreased. For the further increase of film thickness, Ms decreased slowly and the magnetization of unit area exhibited a fluctuation behavior. Moreover, the magnetic anisotropy degenerated with the increase of film thickness. The possible causes for the thickness effects were discussed.

The mechanical strength in germanium-doped Czochralski silicon (GCz-Si) wafers has been investigated through the on-line warpage statistics analysis, indentation tests, and fracture structure measurements. It was found that the wafer warpage during manufacturing processes could be statistically suppressed by the germanium doping slightly. The enhancement effect of germanium doping on the mechanical strength in GCz-Si wafers could be shown obviously when the germanium concentration was higher than 1018cm−3. Meanwhile, the fracture strength for both the as-grown and the postannealed GCz-Si wafers might be greater compared to that of the conventional Czochralski (Cz-Si) wafers. Moreover, the generation and mobilization of the dislocations induced by indentation in Cz-Si wafers could be suppressed by the germanium doping. These phenomena are interpreted through a dislocation pinning-up effect associated with the smaller-sized higher-density oxygen precipitates formed in GCz-Si wafers.

Thermodynamic theory is applied to study the effect of stress on the polarization of Bi4Ti3O12 films with a two-dimensional model. The spontaneous polarizations and free energies are calculated for three possible kinds of orientations of the Bi4Ti3O12 cell and nine ferroelectric phases in the Bi4Ti3O12 films. The stress effect on the spontaneous polarization caused by the lattice distortion is small and can be neglected for all the stable ferroelectric phases, whereas the domain reorientation induced by the competition between the external stress and a gradient intrinsic stress leads to a significant change of spontaneous polarization in Bi4Ti3O12 films. The calculation result agrees well with the experimental result on Nd-doped Bi4Ti3O12 films.