Optimizing profile line interval for enhanced accuracy in rock joint morphology and shear strength assessments

2D profile lines play a critical role in cost-effectively evaluating rock joint properties and shear strength.However, the interval(ΔI_(L)) between these lines significantly impacts roughness and shear strength assessments. A detailed study of 45 joint samples using four statistical measures across 500 different ΔI_(L)values identified a clear line interval effect with two stages: stable and fluctuation-discrete.Further statistical analysis showed a linear relationship between the error bounds of four parameters,shear strength evaluation, and their corresponding maximum ΔI_(L)values, where the gradient k of this linear relationship was influenced by the basic friction angle and normal stress. Accounting for these factors,lower-limit linear models were employed to determine the optimal ΔI_(L)values that met error tolerances(1%–10%) for all metrics and shear strength. The study also explored the consistent size effect on joints regardless of ΔI_(L)changes, revealing three types of size effects based on morphological heterogeneity.Notably, larger joints required generally higher ΔI_(L)to maintain the predefined error limits, suggesting an increased interval for large joint analyses. Consequently, this research provides a basis for determining the optimal ΔI_(L), improving accuracy in 2D profile line assessments of joint characteristics.

Strain anisotropy models for refined diffraction line profile analysis in cubic metals

The present work examined the anisotropy magnitudes obtained from different elastic models of cubic metals(Cu,5383 Al alloy,FCC austenite steel and BCC steel)to explore the origin of strain anisotropy.The results showed that stable intersections were observed from the modeled and experimental plots of the reciprocal elastic modulus(1/Ehkl)and orientation parameter(Γ).The effectiveness of quasi elasto-plastic model based method in correcting strain anisotropy was further verified in cold-worked specimens.For the important input parameters in dislocation model based diffraction line profile analysis methods,the average diffraction contrast factors(■)of dislocations were observed to depend on elastic constants.Interesting intersections were found from linear dependence of■onΓ.The conventional input■values indicated distinct dependencies on given elastic constants in diffraction line profile analysis.Accordingly,a refined approach was proposed by adopting the optimized intersections as input values,by which more reliable results could be obtained in practical applications.

Stark-Broadened Profiles of the Spectral Line P_α in He Ⅱ Ions

We report a systematic method to perform calculations of spectral line broadening parameters in plasmas. This method is applied to calculate Stark-broadening line profiles of Pα（n = 4 → n = 3） transitions under certain specific plasma conditions, by treating this case as an example. In the framework of the fully relativistic Dirac R- matrix theory, we calculate the electron-impact broadening operators, which are assumed to be diagonal matrix to simplify the situation. The electric microfield distribution function is calculated by retaining Hooper＇s formalism. The dipole matrix elements and atomic structure parameters used in these calculations have been obtained from atomic structure GRASP code. Based on this required data, we calculate the Stark-broadened line profiles of the Paschen spectral lines in He Ⅱ ions in a systematic manner. Overall, there is a very good agreement between our calculated Stark-broadened line profiles and other line Our reported spectral line-broadening data have real also play a fundamental role in plasma modeling. broadening numerical simulation codes （Sire U and MELS）. applications in plasma spectroscopy, plasma diagnosis and

Absorption Line Profile Recovery Based on TDLS and MEMS Micro-Mirror for Photoacoustic Gas Sensing

A novel and efficient absorption line recovery technique is presented.A micro-electromechanical systems(MEMS) mirror driven by an electrothermal actuator is used to generate laser intensity modulation through the mirror reflection.Tunable diode laser spectroscopy(TDLS) and photoacoustic spectroscopy(PAS) are used to recover the target absorption line profile which is compared with the theoretical Voigt profile.The target gas is 0.01% acetylene(C2H2) in a nitrogen host gas.The laser diode wavelength is swept across the P17 absorption line of acetylene at 1 535.4 nm by a current ramp,and an erbium-doped fibre amplifier(EDFA) is used to enhance the optical intensity and increase the signal-to-noise ratio(SNR).A SNR of about 35 is obtained with 100 mW laser power from the EDFA.Good agreement is achieved between the experimental results and the theoretical simulation for the P17 absorption line profile.

X-ray Diffraction Line Profile Broadening of Fe_(50)Pd_(50) Alloy Ultrafine Particles

The composition distribution in Fe50Pd50 alloy ultrafine particles prepared by inert gas condensation method was investigated in details by means of X-ray diffraction technique through deconvolution of the X-ray diffraction data. The microscopic composition distribution in the alloy UFP was identified, which is caused by nonuniformity of the melt, fractional distillation during the evaporation process and statistical fluctuation during nucleation and coalescence of the alloy particles. The composition distribution affects the properties of the alloy UFP

Unusually Broadened Spectral Profiles Observed in Solar Prominences

After surveying the spectra of 39 prominences observed by the Multi-channel Infrared Solar Spectrograph at Purple Mountain Observatory and the 25 cm coronagraph at the Norikura Solar Observatory, we found that about 28% of them show small spatial scale (6''–8'') and short time scale (tens of seconds to a few minutes), unusual large broadening and large shift velocities in spectral lines including Hα, Hβ, H, Ca II H, Ca II K, Ca II 8542?, He I D3 and He I 10830?. We present in detail two typical events observed respectively on 2002 May 27 and 1981 August 2. The full-width at half maximum of the widest profile of the 2001 prominence is 1.8? for Hα and 2.9 ? for He I 10830?, while that of the 1981 prominence is 5.3 ? for Hβ, 3.6 ? for Ca II K, 4.0 ? for Ca II H and 2.8 ? for He I D3. Such broadenings generally occur at a level of several-thousand kilometres above the chromosphere. Further, most of these prominences manifest a rotation of (0.4–1.35)×10-2 rads s?1 pointing to the Sun and large line-of-sight velocities of 20–200 km s?1. Some of these events correspond in time to an enhancement or a small peak in the GOES X-ray flux, indicating the existence of high energy process at work. These prominences generally display discernible changes in the Hα morphology around the time of large broadening, but do not show Hα brightening or overall eruption except for a few small surge-like events, hence, they are hardly observed in daily Hα patrols. According to the characteristics of their Hα structures and spectral properties, we infer these events are small-scale eruptions similar to nano-flares, which may contribute to the mass and energy transported into the corona. Large turbulent velocities of 25–120 km s?1 are responsible for the observed broadenings.

An Analysis of Average Pulsar Profiles and A Study of the ρ-P relation of Pulsars

Using the method of Gaussian Fit Separation of Average Profile (GF-SAP), we re-examine the average profiles of nine pulsars at several frequencies, ranging from 408-1642 MHz. This method enables us to obtain the number of components for each pulsar, and the parameters for each component, the width, position and amplitude. The ρ-P relation for the inner cone and outer cone are studied separately, and the results are, respectively, ρ = p-0.51±0.05 and ρ= p-0.42±0.06 The results can be interpreted as a confirmation of the double-cone structure of pulsar emission beams. The altitudes of emission region, and the radius-to-frequency-map (RFM) are also examined; for the outer cone, we obtained γ(v) ∝v-0.19±0.09.

Line Broadening in a Limb Flare: Derivation of Macro-turbulent Velocity Fields

The line profiles of Ha in a limb flare on 1998 November 11 appear to be unusually broadened. It is considered that macro-turbulence (or macroscopic mass motions) may be one of the main causes. We use an inversion technique to extract the probability distribution of the line-of-sight velocity in the flare. There exist some differences between the velocity distributions deduced from Ha and from Ca II λ8542, which may be because the two lines depend differently on the temperature and velocity. Since the loop density is high, we obtain a rather short cooling time (several tens of seconds) from the hot X-ray loops to the cool loops visible in Ha. Possible origins of the large scale motions are discussed.

On the emission lines in active galactic nuclei with relativistic jets

The effect of the observed continuum emitted from a relativistic jet on the measurement of the full width at half maximum （FWHM） of an emission line is analyzed. If the jet contribution is not properly subtracted, the FWHM of the line could seem narrower than it should. The cases of an emission line detected in BL Lac objects and γ-ray Narrow-Line Seyfert 1 galaxies （γ-NLS1s） are addressed. It is shown that the smallness of the observed FWHM of the Lyα lines detected in three well-known BL Lacs is an effect due to the combined action of both the relativistic jet and a weak accretion disk. Once the Doppler boosting effect of the jet continuum is removed, the intrinsic FWHM values of the lines are found to be in the usual range. By contrast, the narrow permitted lines in γ-NLS1s are really narrow, since the disk and the lines are much more powerful. This also confirms that γ-NLS1 is really a new class of γ-ray emitting AGN, different from blazars and radio galaxies.

Properties of the He I 10830 Line in Solar Flares

We study the properties of the He I 10830 A line in nine selected solar flares, using spectral data obtained with the Multi-channel Infrared Solar Spectrograph （MISS） at Purple Mountain Observatory （PMO） and photospheric images from the Michelson Doppler Imager （MDI） onboard the Solar and Heliospheric Observatory （SOHO）. Our results indicate that, over an area of 3″- 8″, the He I 10830 A line shows emission exceeding the continuum in nearby quiet region when the Geostationary Operations Environmental Satellite （GOES） X- ray class of the flare reaches a threshold value （C4.5）. The He I 10830 A line emission is detected only in the kernels of the Ha brightenings, but is not associated with the size of the flare. It is found that, whenever the He I 10830 Aline shows excess emission over the nearby continuum both the Ha and the Ca Ⅱ 8542 A lines display enhanced intensities exceeding their preflare intensities. The He I 10830A line emission can occasionally extend into the umbra of the involved sunspot, which is inconsistent with previous studies. The weak com- ponent of He I 10830A line changes from emission to absorption earlier than does the main component. Our results favor the photoionization-reconnection mechanism for the excitation of the He I 10830fi, line.

Measurements of spectral lines observed with Hinode/EIS as implications for coronal heating

We have measured the line widths and nonthermal velocities in 12 solar regions using high resolution EUV data taken by Hinode/EIS. We find that there exists a positive correlation between the intensity and nonthermal velocity for the Fe xII emission line as well as some other lines. The correlation coefficients decrease from the disk center to the limb. However, the nonthermal velocities of a particular spectral line do not vary much in different regions, so they are considered isotropic. In particular, we find that for a coronal loop structure, the largest widths and nonthermal velocities occur at the footpoints, where outflows appear. Based on these observational results, we discuss several physical processes responsible for coronal heating.

Ha Line Polarization in the 2B/X4.8 Flare of 2002 July 23

On 2002 July 23, a 2B/X4.8 flare was observed in the Hα line spec-tropolarimetrically by the Large Solar Vacuum Telescope of Baikal AstrophysicalObservatory. Linear polarization of 3%-10% was detected in the Hα line, particu-larly where the line showed central reversal. The linear polarization is mainly radialon the solar disk and appears at the impulsive phase of the hard X-ray and γ-raybursts. It is limited to some relatively small regions of the flare. The polarizationin a limited small region (～ 4″ - 5″) changed its direction within a short period oftime (～ 10s).

X-ray Emission Lines in GRB Afterglows: Evidence for a Two-component Jet Model

X-ray emission lines have been observed in X-ray afterglows of several T-ray bursts （GRBs）. It is a major breakthrough for understanding the nature of the progenitors. It has been proposed that the X-ray emission lines can be well explained by the Geometry-Dominated models, but in these models the illuminat- ing angle is much larger than that of the collimated jet of the GRB. For GRB 011211, we have obtained an illuminating angle of about 0 - 45°, while the angle of the GRB jet is only 3.6°. So we propose that the outflow of GRBs with emission lines should have two distinct components： a wide component that illuminates the reprocessing material and produces the emission lines and a narrow one that produces the GRB. Observations show the energy for producing the emission lines is higher than that of the GRB. In this case, when the wide component dominates the afterglows, a bump should appear in the GRB afterglow. For GRB 011211, the bump should occur within 0.05 days of the GRB, which is obviously too early for the observation to catch it. Alongside the X-ray emission lines there should also be a bright emission component between the UV and the soft X-rays. These features can be tested by the Swift satellite in the near future.

Performance of FAST with an Ultra-Wide Bandwidth Receiver at 500–3300 MHz

The Five-hundred-meter Aperture Spherical radio Telescope(FAST)has been running for several years.A new ultra-wide bandwidth(UWB)receiver,simultaneously covering 500-3300 MHz,has been mounted in the FAST feed cabin and has passed a series of observational tests.The whole UWB band is separated into four independent bands.Each band has 1,048,576 channels in total,resulting in a spectral resolution of 1 kHz.At 500-3300 MHz,the antenna gain is around 14.3-7.7 K Jy^(-1),the aperture efficiency is around 0.56-0.30,the system temperature is around 88-130 K,and the half-power beamwidth is around 7.6'-1.6'.The measured standard deviation of pointing accuracy is better than~7.9"when zenith angle is within 26.4°.The sensitivity and stability of the UWB receiver are confirmed to satisfy expectations through spectral observations,e.g.,HI and OH.The FAST UWB receiver has already demonstrated good performance in capturing sensitive observations for various scientific goals.

Using Impervious Surfaces to Detect Urban Expansion in Beijing of China in 2000s

The change of impervious surface area(ISA) can effectively reveal the gradual process of urbanization and act as a key index for monitoring urban expansion. Experiencing rapid growth of the built environment in the 2000 s, urban expansion of Beijing has not been fully characterized through ISA. In this study, Landsat TM images of Beijing in 2001 and 2009 were obtained, and the eight-year urban expansion process in Beijing was analyzed using the ISA extracted by means of the vegetation-imperious surface-soil(V-I-S) model. From the spatial variation in ISA, the ring structure of urban expansion in Beijing was significant during the study period, with decreasing urban density from the city center to the periphery. In the ring road analysis, the most dramatic changes of ISA were found between the fifth ring and the sixth ring. This area has experienced the most new residential development, and is currently the main source of urban expansion. The typical profile lines revealed the directional characteristics of urban expansion. The east-west profile was the most urbanized axes in Beijing, while ISA change in the east-north profile was more significant than in the other five profiles. Moreover, the transition matrix of ISA levels revealed an increase in urban density in the low density built areas; the Moran′s I index showed a clear expansion of the central urban area, which spread contiguously; and the standard deviational ellipse indicated the northeast was the dominant direction of urban expansion. These findings can provide important spatial control guidelines in the next round of national economic and social development planning, overall urban and rural planning, and land use planning.

Gene expression profile differences in high and low metastatic human ovarian cancer cell lines by gene chip

Objectives To study the difference between gene expressions of high (H0-8910PM) and low (HO-8910) metastatic human ovarian carcinoma cell lines and screen novel associated genes by cDNA microarray. Methods cDNA retro-transcribed from equal quantities of mRNA derived from high and low metastatic tumor cells or normal ovarian tissues were labeled with Cy5 and Cy3 fluorescein as probes. The mixed probe was hybridized with two pieces of BioDoor 4096 double dot human whole gene chip and scanned with a ScanArray 3000 laser scanner. The acquired image was analyzed by ImaGene 3.0 software. Results A total of 355 genes with expression levels more than 3 times larger were found by comparing the HO-8910 cell with normal ovarian epithelial cells. A total of 323 genes with expression levels more than 3 times larger in HO-8910PM cells compared to normal ovarian epithelium cells were also detected. A total of 165 genes whose expression levels were more than two times those of HO-8910PM cells compared to their mother cell line (HO-8910) were detected. Twenty-one genes with expression levels 】3 times were found from comparison of these two tumor cell lines.Conclusions cDNA microarray techniques are effective in screening differential gene expression between two human ovarian cancer cell lines (H0-8910PM; HO-8910) and normal ovarian epithelial cells. These genes may be related to the genesis and development of ovarian carcinoma. Analysis of the human ovarian cancer gene expression profile with cDNA microarray may help in gene diagnosis, treatment and prevention.

The fundamental performance of FAST with 19-beam receiver at L band

The Five-hundred-meter Aperture Spherical radio Telescope(FAST) has passed national acceptance and finished one pilot cycle of ‘Shared-Risk’ observations. It will start formal operation soon. In this context, this paper describes testing results of key fundamental parameters for FAST, aiming to provide basic support for observation and data reduction of FAST for scientific researchers. The 19-beam receiver covering 1.05–1.45 GHz was utilized for most of these observations. The fluctuation in electronic gain of the system is better than 1% over 3.5 hours, enabling enough stability for observations. Pointing accuracy,aperture efficiency and system temperature are three key parameters for FAST. The measured standard deviation of pointing accuracy is 7.9′′, which satisfies the initial design of FAST. When zenith angle is less than 26.4°, the aperture efficiency and system temperature around 1.4 GHz are ~0.63 and less than 24 K for central beam, respectively. The sensitivity and stability of the 19-beam backend are confirmed to satisfy expectation by spectral HI observations toward NGC 672 and polarization observations toward 3 C 286. The performance allows FAST to take sensitive observations for various scientific goals, from studies of pulsars to galaxy evolution.

X-ray diffraction analysis of cold-worked Cu-Ni-Si and Cu-Ni-Si-Cr alloys by Rietveld method

Cold worked and annealed supersaturated Cu-2.65Ni-0.6Si and Cu-2.35Ni-0.6Si-0.6Cr alloys were studied. The microstructural parameters evolution, including crystallite size, root mean square strain and dislocation density was analyzed using Materials Analysis Using Diffraction software （MAUD）. The parameters for both alloys have typical values of cold deformed and subsequently annealed copper based alloy. A net change of the crystallite size, root mean square strain and dislocation density values of the alloys aged at 450 °C for 2.5-3 h seems corresponding to the recovery and recrystallization processes. Addition of Cr as quaternary element did not lead to any drastic changes of post deformation or ageing microstructural parameters and hence of recovery-recrystallization kinetics.

Can the temperature of Ellerman Bombs be more than 10 000 K？

Ellerman bombs （EBs） are small brightening events in the solar lower atmosphere. By their original definition, the main characteristic of EBs is the two emission bumps in both wings of chro- mospheric lines, such as Hα and Ca II 8542A lines. Up to now, most authors have found that the temperature increase of EBs around the temperature minimum region is in the range of 600-3000 K. However, with recent IRIS observations, some authors proposed that the temperature increase of EBs could be more than 10 000 K. Using non-LTE semi-empirical modeling, we investigate the line profiles, continuum emission and radiative losses for EB models with different temperature increases, and com- pare them with observations. Our result indicates that if the EB maximum temperature reaches more than 10000K around the temperature minimum region, then the resulting Hα and Call 8542A line profiles and the continuum emission would be much stronger than those of EB observations. Moreover, due to the high radiative losses, a high temperature EB compatible with observations. Thus, our study does not higher than 10 000 K. would have a very short lifetime, which is not support the proposal that EB temperatures are higher than 10 000 K.

Diagnostics of Ellerman bombs with high-resolution spectral data

Ellerman bombs （EBs） are tiny brightenings often observed near sunspots. The most impressive characteristic of EB spectra is the two emission bumps in both wings of the Hα and Ca II 8542 A lines. High-resolution spectral data of three small EBs were obtained on 2013 June 6 with the largest solar telescope, the 1.6 m New Solar Telescope at the Big Bear Solar Observatory. The characteristics of these EBs are analyzed. The sizes of the EBs are in the range of 0.3＂ - 0.8＂ and their durations are only 3-5 min. Our semi-empirical atmospheric models indicate that the heating occurs around the temperature minimum region with a temperature increase of 2700- 3000 K, which is surprisingly higher than previously thought. The radiative and kinetic energies are estimated to be as high as 5 × 1025 - 3.0 × 10^26 erg despite the small size of these EBs. Observations of the magnetic field show that the EBs just appeared in a parasitic region with mixed polarities and were accompanied by mass motions. Nonlinear force-free field extrapolation reveals that the three EBs are connected with a series of magnetic field lines associated with bald patches, which strongly implies that these EBs should be produced by magnetic reconnection in the solar lower atmosphere. According to the lightcurves and the estimated magnetic reconnection rate, we propose that there is a three phase process in EBs： pre-heating, flaring and cooling phases.