Search

Arthrocentesis for arthralgia of the temporomandibular joint (TMJ) is often only indicated when conservative, non-surgical interventions have failed. However, performing arthrocentesis as initial therapy may facilitate earlier and better recuperation of the joint. The aim of this study was to assess the efficacy of this therapy with a long-term follow-up. Eighty-four patients were randomly allocated to receive either arthrocentesis as initial treatment (n = 41) or non-surgical intervention (n = 43). Pain (100-mm visual analogue scale, VAS) and mandibular function impairment questionnaire scores (MFIQ, 0–100) were recorded at 3, 12, and 26 weeks, and ≥ 5 years (median 6.2, interquartile range 5.6–7.4 years). Univariable analyses were performed and linear mixed-effect models were constructed. Patients in the arthrocentesis group experienced significantly lower TMJ arthralgia compared to those treated non-surgically (pain during movement: −10.23 mm (95% confidence interval −17.86; −2.60); pain at rest: − 8.39 mm (95% confidence interval −13.70; −3.08)), while mandibular function remained similar in the two groups (MFIQ −2.41 (95% confidence interval −8.61; 3.78)). Of the final sample, 10 patients (10/39, 26%) in the non-surgical intervention group and two patients (2/34, 6%) in the arthrocentesis group received additional treatment during follow-up. Thus, initial treatment with arthrocentesis reduced TMJ arthralgia more efficaciously than non-surgical intervention in the long term, while maintaining similar mandibular function.

Background: Although numerous studies have reported a decrease in dementia risk in the last two decades, it is unclear whether dementia-free cognitive function is also changing across generations. Objective: The objective was to systematically evaluate the published data on generational differences in cognitive function in the older population. Methods: Searches were performed on PubMed, Embase, and PsychInfo for articles published in English before 28 June 2021. Included studies were from population-based samples that reported generational differences in cognition in individuals without dementia, aged ≥60 years. Results: 28,101 studies were identified and 15 selected covering the period from 1971 to 2015: including studies from China, Europe, and the USA. The results show generally consistent findings of improvements or stability in dementia free cognitive function in later versus earlier born generations, but not for all cognitive domains. Prevalence of mild cognitive impairment and cognitive impairment no dementia has remained stable in the USA, UK, and China over the last two decades. Results: Prevalence of vascular related mild cognitive impairment has increased in China. Improvements in cognition may only partially be explained by increased educational attainment across generations. Conclusion: This review provides evidence for generational effects in dementia-free cognitive function, predominately stability or improvements in performance, in later compared to earlier born individuals across different world regions. There is an urgent need to determine the factors driving such changes and whether they are being experienced in all world regions, particularly low- and middle-income countries where the burden of cognitive impairment is greatest and rising.

ObjectivesCognitive problems following stroke are of key concern to stroke survivors. Discussing risk of dementia at the time of stroke could have implications for follow-up care. However, informing someone who has just had a stroke about risk of dementia could cause distress. This survey explored healthcare professionals’ views on discussing risk of post-stroke dementia at the time of stroke.Materials and MethodsThis online survey was aimed at all UK healthcare professionals who care for patients with stroke. The survey was distributed via the mailing lists of seven professional stroke-related organisations and Twitter. Descriptive statistics were used to summarise findings.ResultsSixty healthcare professionals completed the survey. Healthcare professionals were aware of the main risk factors associated with post-stroke dementia (e.g. previous stroke, age). Most respondents (N=34/60, 57%) thought that patients with acute stroke would benefit from knowing if they are at high risk of dementia, and 75% (N=45/60) agreed that carers would benefit. Despite this, the majority of healthcare professionals (N=47/53, 89%) who cared for patients with acute stroke in the past year said they rarely/never discussed dementia with their patients. Most respondents (N=46/60, 77%) thought risk of dementia should be discussed 1-6 months post-stroke.ConclusionAlthough healthcare professionals felt it would be helpful to discuss risk of post-stroke dementia, in practice, most said that they rarely or never discussed this with their patients. Stroke survivors could benefit from a healthcare system that offers appropriate follow-up care and support to patients at high risk of dementia.

In this paper, I discuss how the six-steps procedure of LBT can be applied to the case of Mr. H., who believes that it is reasonable for him to feel hopeless for his future. During the practicum session, we explore his emotional reasoning, identify and refute cardinal fallacies in the premises, and identify guiding virtues according to the fallacies. Further, according to Mr. H’s preference, we explore and apply the uplifting philosophy associated with the ideas of Buddhism. I conclude the paper with reflections on how both Mr. H and myself learnt from this valuable experience.

During tumor development, cancer cells constantly confront different types of extracellular barriers. However, fundamental questions like whether tumor cells will continue to grow against confinement or away from it and what key factors govern this process remain poorly understood. To address these issues, here we examined the growth dynamics of human lung epithelial carcinoma A549 cells partially confined in micrometer-sized cylindrical pores with precisely controlled wall stiffness. It was found that, after reaching confluency, the cell monolayer enclosed by a compliant wall was able to keep growing and pushing the boundary, eventually leading to a markedly enlarged pore. In contrast, a much reduced in-plane growth and elevated strain level among cells were observed when the confining wall becomes stiff. Furthermore, under such circumstance, cells switched their growth from within the monolayer to along the out-of-plane direction, resulting in cell stacking. We showed that these observations can be well explained by a simple model taking into account the deformability of the wall and the threshold stress for inhibiting cell growth. Interestingly, cadherins were found to play an important role in the proliferation and stress buildup within the cell monolayer by aggregating at cell-cell junctions. The stiff confinement led to an elevated expression level of cadherins. Furthermore, inhibition of N-cadherin resulted in a significantly suppressed cell growth under the same confining conditions.

The electronic and optical properties of Si and/or S (co)doped anatase TiO2 are investigated by density function theory plus U calculations. Results show that the synergistic effects of Si and S codoping result in higher visible-light absorption compared with pure and Si or S monodoped TiO2. Moreover, with increasing S doping concentration, the band gap of Si/S-codoping system becomes narrower, and simultaneously the band edge positions may be suitable for water splitting. Additionally, the defect formation energy calculations indicate that Si doping can enhance the thermal stability of TiO2 under O-rich condition.

Silicon carbide nanotubes (SiCNTs) with special morphology synthesized by supercritical hydrothermal method at 470 °C and 8 MPa have been reported in this paper. SiCNTs with special morphology were characterized by transmission electron microscopy (TEM) and high-resolution TEM (HRTEM). There are two kinds of silicon carbide with special morphology: One is oval SiCNTs with small aspect ratio, the other is bamboo cone-shape structure. SiCNTs have been analyzed by fluorescence spectrometer. The results indicate that the SiCNTs have strong photoluminescence (PL) property. The SiCNTs with oval shape are one kind of intermediate state of growth process of nanotube. The growth mechanism of silicon nanotubes has been proposed based on experiment data. The investigations of growth mechanism of SiCNTs with bamboo structure show that the defect produced in the growth process play the important role in SiCNTs with special structure.

Sufficient data has proven that radon and its decay products are the principal noso-genesis to lung and other related cancers. To reduce and control the effects of radon pollution, standards to limit indoor radon concentration have been issued in China and other countries or regions. To echo this, an anti-radon coating has been studied and developed with partial funding support from the Innovation and Technology Fund of the Government of the Hong Kong Special Administrative Region. The coating had been experimented in a newly constructed building where the recorded maximum and average hourly background radon concentrations were recorded at 130,000 Bq m−3 and 100,000 Bq m−3 respectively under a concealed condition. The experimental results from application of the coating have shown an anti-radon efficiency of up to 99.85%, which decreases the indoor radon background concentration down to a safe level in a 72-h measurement. The coating still remains in a good condition currently and effective in anti-radon three years after the application.

Introduction Inter-facility transport (IFT) is a dynamic process and its quality largely depends on pre-transport preparation, emergency equipment support and recognition of possible en route adverse events. This study aims to evaluate knowledge of IFT among emergency nurses of three Accident and Emergency Departments in Hong Kong. Methods Questionnaires were distributed to registered nurses of the three departments. Data was sought on participants’ characteristics, knowledge on equipment preparation and management of en route adverse events. Four clinical IFT scenarios were set for participants and answers were scored. Measured outcomes were defined as (1) relationships between clinical experience and relevant training in IFT with questionnaire results, (2) staff knowledge of the equipment carried routinely in ambulances and (3) the en route adverse events encountered according to the participants’ past experience. Results Participants’ test scores ranged from 24 to 37 (out of 40) with a mean of 30.6 (95% confidence interval 29.7–31.5). Participants with more clinical experience demonstrated significantly better test scores (p

Silicon nanochains over 1 μm in length and 50–100 nm in diameter have been synthesized by hydrothermal synthesis with silicon powders as start materials and de-ionized water as reaction medium, the growth condition was controlled at 470 °C and 9.7 MPa in a sealed reaction kettle. The morphology and microstructure of the production were characterized by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED); the results revealed that the silicon nanochains have diamond structure. Energy dispersive X-ray spectrum (EDS) was used to analyze the composition of the final production and the possible growth mechanism of silicon nanochain under supercritical hydrothermal condition was proposed.

Large-scale amorphous silicon oxide nanowires (SiONWs) have been synthesized from silicon monoxide powder under supercritically hydrothermal conditions. The SiONWs with smooth surface can reach tens of microns long. Selected area electron diffraction (SAED) shows that the samples are completely amorphous. Energy-dispersive X-ray spectrometry (EDX) analysis reveals that the SiONWs consist of Si and O elements in atomic ratio approximately to 1:1.5. Photoluminescence (PL) shows luminescence in both blue and visible. During the growth process, the H + and OH − blocks the defects located on the surface of the SiONWs and lead to the constant growth of the SiONWs.

Hydrothermal method with silicon monoxide as starting material was used to synthesize silicon nanowires (SiNWs). Transmission electron spectroscopy demonstrates that SiNWs have smooth surface and about 35 nm in diameter, micrometers in length. High-resolution transmission electron spectroscopy shows that each nanowire consists a polycrystalline Si core and an amorphous silica sheath. Si and silicon oxide are proposed to generate from SiO under the high temperature and high pressure of hydrothermal conditions. The growth mechanism of SiNWs is proposed as the oxide-assisted growth mechanism.

Si K-edge XAFS was used to characterize a stoichiometric SiC film prepared by pulsed KrF laser deposition. The film was deposited on a p-type Si(1 0 0) wafer at a substrate temperature of 250 °C in high vacuum with a laser fluence of ∼5 J/cm 2 . The results reveal that the film contains mainly a SiC phase with an amorphous structure in which the Si atoms are bonded to C atoms in its first shell similar to that of crystalline SiC powder but with significant disorder.

Chemical composition analysis of apatites and their fluid inclusions from Yu'erya granite was carried out by synchrotron radiation X-ray fluorescence (SRXRF) microprobe. The result shows that all these apatite crystals have a similar chemical signature, with Ca, P, Cl, Mn, Fe, K, S, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Er, Yb, Lu, Sr, Y, Zr, U, Th, etc. The rare earth elements chondrite-normalized pattern indicates that these apatites are derived from S-type granite. It is shown by the SRXRF analysis that Zn, Cu and Cl are main components of fluid inclusions in apatites. It is the first time that SRXRF analysis is successfully applied in determination of composition of single fluid inclusions in apatite crystals. This technique was proved to be suitable for crystals with homogenously distributing components and thin covering layer would help to determine the composition of fluid inclusions.

Refined silicon nanowires have been prepared by a mild etching process and suspended into liquid in order to make them manageable for individual characterization. A transmission electron microscopy (TEM) study has revealed that the etching starts selectively at defect sites on the wires. This implies that the refined wires have many fewer defects than those made of raw materials. Efforts have been made to mount single nanowires onto the desired electrodes by electrophoresis. Compared with the commonly used microactuation method in the field, this is a far more realistic practical use of the wires that has an industrial value.

By using YOHKOH soft X-ray images, vector magnetograms and Hα filtergrams, the energetics of the brightening event of May 18, 1994 has been studied. It occurred in a nearly potential magnetic configuration as shown by the comparison between the magnetic extrapolation(linear force free field) and the large scale soft X-ray loops. This event is related to the emergence of a new magnetic flux. The brightening points of Hα and soft X-ray are located at computed separatrices associated with field lines which are tangent to the photosphere. This brightening may be a signature of reconnection taking place between the pre-existing non-potential loops and the new emerging small loops. The magnetic energy provided by reconnection is likely to be stored in the non-potential loops and shearing emerging flux. A phenomenological model is offered.

The tensile behavior of composite laminate structures repaired by bonding external patches was studied in the paper. Two different types of patches including wedge patches and inverted wedge patches were used and failure mechanisms, failure load and strength predictions were studied. A convenient and fast method of building 2-D finite element modeling (FEM) of laminate structure repaired was proposed and the strength of repaired laminate structures was calculated by FEM. The results showed that more than 80% tensile strength of the undamaged laminate could be recovered by bonding patch repairs. Moreover, the results indicated that the strength of inverted wedge patches repair were higher than that of wedge patches repair. FEM simulation results indicated that high stress concentration was found along the edges of invert patches and the most weakness part located in the adhesive bondline. FEM analysis results showed that the strength predicted matched well with the test strength.

By using Yohkoh soft X-ray images, vector magnetograms, and Hα filtergrams, the brightening event that occurred on 1994 May 18 has been studied in detail. It occurred in a nearly potential large-scale magnetic configuration as shown by the comparison between the magnetic extrapolation (linear force-free field) and the large-scale soft X-ray loops. This event is related to the emergence of a new magnetic flux of about 3 × 1020 Mx. The impulsive enhancement of the emerging flux occurs about 20 minutes before the peaks of the Hα and soft X-ray brightening and lasts for about 10 minutes. This brightening may be a signature of reconnection taking place between the preexisting nonpotential loops and the new emerging small loops. The magnetic energy provided by reconnection is likely to be stored in the nonpotential loops and the emerging flux as implied by the vector magnetograms. By using the electron temperature and the electron density of the brightening event derived from the analysis of the Yohkoh data, an energy budget has been estimated. The result indicates that the energy needed can be reasonably provided by magnetic reconnection.

The effect of heat conduction on 2.5D magnetic reconnection, similar to that in Kopp-Pneuman model, is numerically studied. It is shown that the heat conduction accelerates the reconnection, increases the amount of shrinkage of the closed field lines, and increases the average rise speed of the SXR loop. MHD slow shocks contribute to the SXR loop heating. When the timescale of heat conduction is shorter than the Alfven timescale, and adiabatic slow shock is dissociated into an isothermal slow shock and a heat conduction front.

We performed 2.5-dimensional numerical simulations of magnetic reconnection for several models, some with the reconnection point at a high altitude (the X-type point in magnetic reconnection), and one with the reconnection point at a low altitude. In the high-altitude cases, the bright loop appears to rise for a long time, with its two footpoints separating and the —eld lines below the bright loop shrinking, which are all typical features of two-ribbon —ares. The rise speed of the loop and the separation speed of its footpoints depend strongly on the magnetic —eld to a medium extent on the density and B 0 , o 0 , weakly on the temperature the resistivity g, and the length scale by which the size of current T 0 , L 0 , sheet and the height of the X-point are both scaled. The strong dependence means that the Lorentz B 0 force is the dominant factor; the inertia of the plasma may account for the moderate dependence; o 0 and the weak g dependence may imply that ii fast reconnection ˇˇ occurs; the weak dependence implies L 0 that the —aring loop motion has geometrical self-similarity. In the low-altitude case, the bright loops cease rising only a short time after the impulsive phase of the reconnection and then become rather stable, which shows a distinct similarity to the compact —ares. The results imply that the two types of solar —ares, i.e., the two-ribbon —ares and the compact ones, might be uni—ed into the same magnetic reconnection model, where the height of the reconnection point leads to the bifurcation. Subject headings: MHDmethods: numericalSun: —aresSun: magnetic —elds

Nanocrystalline carbon–boron nitride (C–BN) compounds have been synthesized by solid phase mechanical alloying of Cx(BN)1−x powder with various carbon fractions x. Ternary mixing within the structures was found to occur after ball milling and hot-pressing. High temperature recrystallization led to a change in structural configuration, specifically, into alternating layers of graphite and BN. The hardness of the C–BN plates increased when the carbon fraction x increased from 0 to 0.5, and then decreased when x increased thereafter. The composite C0.5(BN)0.5 possessed the highest hardness equalling twice that of nanocrystalline graphite and three times that of nanocrystalline BN. The lattice parameters c and a were larger and smaller, respectively, than those of graphite and hBN. The property differences between the initial and resultant materials were attributed to the structural transformation of the original substances into heterogeneously layered Cx(BN)1−x compounds. New additional peaks were also observed and matched those of shock-wave compressed BN.

Magnetohydrodynamic (MHD) equations are numerically solved to study 2.5-dimensional magnetic reconnection with field-aligned heat conduction, which is also compared with the adiabatic case. The dynamical evolution starts after anomalous resistivity is introduced into a hydrostatic solar atmosphere with a force-free current sheet, which might be similar to the configuration before some solar flares. The results show that two jets (i.e., the outflows of the reconnection region) appear. The downward jet collides with the closed line-tied field lines, and a bright loop is formed with a termination shock at the loop top. As the reconnection goes on, the loop rises almost uniformly with a speed of tens of km s−1, and the two footpoints of the loop separate with a speed comparable to the loop rise speed. Besides the apparent loop motion, the magnetic loops below the loop top shrink weakly. Such a picture is consistent with that given by observations of two-ribbon solar flares. Moreover, the results indicate that the slow MHD shock contributes to the bright loop heating. Some detailed structures of the reconnection process are also discussed.

We report below synthesis of nano-scale silicon wires by using laser ablation at high temperature. By this approach we have been able to produce silicon nano wires (SiNW's) with a very high yield, a uniform diameter distribution and a high purity. The structure, morphology and chemical composition of the SiNWs have been characterized by using high resolution X-ray diffraction (XRD), high resolution electron microscopy (HREM), as well as spectroscopy of energy dispersive X-ray fluorescence (EDAX). Our results should be of great interest to researchers working on mesoscopic physical phenomena, such as quantum confinement effects related to materials of reduced dimensions and should lead to the development of new applications for nano-scale devices, together with providing a powerful method for synthesis of similar one-dimensional conducting and semi-conducting wire.

This paper describes a fracture mechanics approach for analyzing the growth of internal transverse defects in rails known as detail fractures. Analyses are used specifically to determine: (1) the defect size at which a rail failure can be expected when a train is traveling over it and (2) the time for a detail fracture to grow from a given size to the size at which rail failure can be expected. The results from these analyses are shown to depend strongly on ambient temperature. Moreover, the results can be applied to develop damage-tolerant strategies for rail inspection.

The optimisation of a FSF solar cell or a BSF thin film solar cell necessitates an understanding of the characteristics of an illuminated high-low junction. However, except for minority carrier reflection, the photocurrent collection property of the light-generated carriers in the high region by a high-low junction has rarely been treated previously. It is the purpose of this paper to present a simple solution for the contribution of the light-generated current from the high region. The model shows that a high-low junction may be very efficient in light-generated current collection, and this property is primarily responsible for the increase of the short wavelength quantum efficiency using a FSF. The effects of the FSF layer doping concentration and its thickness on the quantum efficiency are discussed by using the computed results; the optimisation of the FSF is then made. The calculations take into account the high doping effects of degeneracy and bandgap narrowing.

Lives predicted by two crack growth rate models are compared with the lives measured in field and laboratory spectrum tests on rail steel. The two models are shown to be equivalent, except that one model reflects average rates and the other, the fastest, measured rates from constant amplitude tests. Comparison with the field test suggests that the stress intensity factor model used to represent a detail fracture growing in a rail head requires some minor modifications. The laboratory tests, performed with load spectra in real sequence order, are shown to be reasonable simulations of the field test. Both the field and laboratory spectrum test crack growth lives are shorter than the lives predicted from the average rate model. This result is attributed to acceleration (load interaction) in the tests.

Aim of the Study Limonium sinense (Girard) Ktze is a Chinese folk medicine used to treat fever, hemorrhage, hepatitis, and other disorders. The present research focused on the protective effects of L. sinense extracts (LSE) against liver damage. Materials and methods In this study the extract from the root of Limonium sinense was used. Aminotransferase activity detection, electron microscopy, mitochondrial function evaluation, RT-PCR and western blot were used to evaluate the hepatoprotection of LSE in LPS/ d -GalN-intoxicated mice. Results Pretreatment with 100, 200 or 400 mg/kg LSE significantly blocked the increase in both serum aspartate aminotransferase (sAST) and serum alanine aminotransferase (sALT) levels induced by treatment with LPS plus d -GalN (LPS/ d -GalN). Ultrastructural observation by electron microscopy showed reduced hepatocyte nuclear condensation and less lipid deposition. The decrease in both the mitochondrial membrane potential (14.6%) and sensitivity to mitochondrial swelling induced by Ca 2+ (45.9%) observed in the liver of LPS/ d -GalN-treated mice were prevented by pretreatment with LSE. In addition, different doses of LSE increased both the transcription and the translation of voltage-dependent anion channels (VDAC), which was down-regulated by LPS/ d -GalN treatment. Conclusions In summary, LSE protects livers against LPS/ d -GalN-induced damage, possibly by mitochondrial mechanisms related to increased expression of VDAC.

The major challenge for cord blood transplantation (CBT) is higher rates of delayed and failed engraftment. In an attempt to broaden the application of CBT to more candidates, ex vivo expansion of hematopoietic stem/progenitor cells in CB is a major area of investigation. The purpose of this study was to employ human BM mesenchymal stromal cells (hBM-MSC) as the feeding-layer to expand CB cells ex vivo.In this study, hBM-MSC were isolated and characterized by morphologic, mmunophenotypic and RT-PCR analysis. The hBM-MSC at passage 3 were employed as the feeding-layer to expand CB CD34(+) cells in vivo in the presence of thrombopoietin, flt3/flk2 ligand, stem cell factor and G-CSF. The repopulating capacity of the ex vivo-expanded CB cells was also evaluated in a NOD/SCID mice transplant experiment.After 1 or 2 weeks of in vitro expansion, hBM-MSC supported more increasing folds of CB in total nucleated cells, CD34(+) cells and colony-forming units (CFU) compared with CB without hBM-MSC. Furthermore, although NOD/SCID mice transplanted with CB cells expanded only in the presence of cytokines showed a higher percentage of human cell engraftment in BM than those with unexpanded CB CD34(+) cells, expanded CB cells co-cultured with hBM-MSC were revealed to enhance short-term engraftment further in recipient mice.Our study suggests that hBM-MSC enhance in vitro expansion of CB CD34(+) cells and short-term engraftment of expanded CB cells in NOD/SCID mice, which may be valuable in a clinical setting.

A novel human leucocyte antigen-DRB1*16 (HLA-DRB1*16) allele (DRB1*1609) has been identified by sequencing-based typing (SBT) in Chinese Han population. This new allele has identical nucleotide sequence to DRB1*160101 in exon 2, except for a single-nucleotide substitution from A to T at position 127. This change leads to an amino acid change from tyrosine to phenylalanin at residue 47 (Y47F). SBT was performed for cloned DRB1*16-specific polymerase chain reaction fragment. The serological phenotype of DRB1*1609 is equivalent to DR16 antigen.

Self-assembled silicon nanotubes with one-dimensional structure have been synthesized from silicon monoxide powder under supercritically hydrothermal conditions with a temperature of 470 degrees C and a pressure of 6.8 MPa. The silicon nanotubes were identified by transmission electron microscopy and high-resolution transmission electron microscopy. The results show that the silicon nanotubes (SiNT) have closed caps. The structures of the silicon nanotubes are hollow inner pore, crystalline silicon wall layers with a 0.31 nm interplanar spacing and 2-3 nm amorphous silica outer layers. Pure crystalline silicon nanotubes survive after etching the silicon nanotubes with 5% HF acid for enough time to imply that the self-assembled silicon nanotubes are stable. A possible theoretical reason for the growth of SiNTs from SiO under supercritically hydrothermal conditions was also proposed.

Rear surface effects in PERL solar cells can lead not only to degradation in the short circuit current and open circuit voltage, but also fill factor. Three mechanisms capable of changing the effective rear surface recombination velocity with injection level are identified, two associated with oxidised p-type surfaces, and the third with two dimensional effects associated with a rear floating junction. Each of these will degrade the fill factor if the range of junction biases corresponding to the rear surface transition, coincides with the maximum power point. Despite the identified nonidealities, PERL cells with rear floating junctions (PERF cells) have achieved record open circuit voltages for silicon solar cells, while simultaneously achieving fill factor improvements relative to standard PERL solar cells. Without optimisation, a record efficiency of 22% has been demonstrated for a cell with a rear floating junction. The results of both theoretical and experimental studies are provided.

Plasma enhancement chemical vapour deposition (PECVD) silicon nitride can grow on alloying device at low temperature. So it can be used as passivation film on devices. The type DD-P250 deposition equipment used in several factories is a special purpose one for PECVD silicon nitride deposition. In this paper the author study various deposition parameters affecting thin film properties with the equipment used in manufacturing line. The optimum ranges of various deposition parameters and the conditions of depositing high quality silicon nitride passivation film are report. A new quantitative explanation is given in this paper on index of refraction vs. velocity of growing.

A range of rear surface structures have been developed and studied for the purpose of improving the performance of buried contact solar cells (BCSC). In particular, improved results are reported for the double grooved BCSC with oxidised p-type rear surface, with V/sub oc/ of 685 mV having been demonstrated. The importance of including an anneal treatment is clearly evident with open circuit voltages typically degrading 60 mV without its inclusion. Devices with the same structure but with a rear floating junction are also evaluated within the study and again the dependence on an anneal is evident for cells with low surface phosphorus concentration. In the highest voltage devices, the rear boron diffused grooves contribute almost 30% of the total device dark saturation current, with test devices achieving V/sub oc/ as high as 694 mV for a BCSC with the rear grooves replaced by photolithographically defined boron diffused contact regions.

Quasi one-dimensional materials have attracted considerable attention in recent years because of its potential to both fundamental physics and nanoelectronic applications. More recently, we have achieved large scale synthesis of silicon nanowires (SINW) at a high growth rate by laser ablation of Si target at 1200 °C. The laser source was a pulsed KrF excimer laser and the Si targets were made by pressing Si powder of 5 microns in size. 50 sccm Ar was used as a carrying gas flowing from the side near the Si target towards a water-cooled copper finger. Si nanowires have been grown with diameters ranging from 3 to 43 nm and several hundreds microns in length after 2 hours of laser ablation of Si target. The SLNWs were analyzed by XRD, Raman, EDS, TEM and HRTEM. Successful large scale synthesis of SINW by laser ablation extends the pulsed laser ablation method from depositing thin films to synthesis of nanowires.

Silicon nanowires have been synthesized by using a high-temperature laser ablation method. Transmission electron microscopic investigation shows that the nanowires are crystalline Si, and have diameters ranging from 3 to 43 nm and lengths up to a few hundreds μm. Raman scattering spectrum shows an asymmetric peak at the same position as that of bulk crystalline silicon. The x-ray diffraction revealed an important contribution from surface oxide. This is due to the high surface-to-volume ratio. Visible photoluminescence (PL) was observed in nanowires with sub-5 nm diameter.