The pressure crashes observed in shot No. 71326 in the Experimental Advanced Superconducting Tokamak are numerically investigated with the three-dimensional, toroidal, and full ...resistive-magnetohydrodynamics code (CLT). Based on the experimental observations, the pressure crash is caused by the nonlinear evolution of the m/n = 2/1 double tearing mode (DTM), where n and m are the toroidal and poloidal mode numbers, respectively. However, we find that the m/n = 2/1 DTM is stable based on the safety factor (q) profile from the equilibrium code EFIT, which indicates that the original q profile is somewhat inconsistent with the actual profile due to q measurement uncertainty. Since there is no motional Stark effect diagnostic for this shot, the local information of the magnetic field is missing, which leads to the largest contribution to the discrepancy. If other information is perfectly known and the q profile is the only uncertainty, then we could provide some information for the EFIT reconstruction by comparing our simulation results with electron cyclotron emission signals to constrain the uncertainty of the q profile to a much smaller region. The influence of plasma rotation and the two-fluids effect is also discussed.
A steady state Level III fate model was established and applied to quantify source–receptor relationship in a coking industry city in Northern China. The local emission inventory of PAHs, as the ...model input, was acquired based on energy consumption and emission factors. The model estimations were validated by measured data and indicated remarkable variations in the paired isomeric ratios. When a rectification factor, based on the receptor-to-source ratio, was calculated by the fate model, the quantitatively verified molecular diagnostic ratios provided reasonable results of local PAH emission sources. Due to the local ban and measures on small scale coking activities implemented from the beginning of 2004, the model calculations indicated that the local emission amount of PAHs in 2009 decreased considerably compared to that in 2003.
•A steady-state fate model could well elucidate the multimedia fate of PAHs.•A rectification factor for correcting the paired isomeric ratio was calculated.•The corrected isomeric ratios were successfully applied to source apportionment.
Based on multimedia model correction, the specific isomeric ratios could provide reasonable apportionments for the local PAHs emission sources.
A new alpha-emitting isotope U-214, produced by the fusion-evaporation reaction W-182(Ar-36,4n) U-214, was identified by employing the gas-filled recoil separator SHANS and the recoil-a correlation ...technique. More precise a-decay properties of even-even nuclei U-216,U-218 were also measured in the reactions of Ar-40, Ca-40 beams with W-180,W-182,W- 184 targets. By combining the experimental data, improved alpha-decay reduced widths delta(2) for the even-even Po-Pu nuclei in the vicinity of the magic neutron number N = 126 are deduced. Their systematic trends are discussed in terms of the N-p N-n scheme in order to study the influence of protonneutron interaction on a decay in this region of nuclei. It is strikingly found that the reduced widths of( 214,216)U are significantly enhanced by a factor of two as compared with the NpNn systematics for the 84 <= Z <= 90 and N < 126 even-even nuclei. The abnormal enhancement is interpreted by the strong monopole interaction between the valence protons and neutrons occupying the pi 1f (7/2) and nu 1f(5/2) spin-orbit partner orbits, which is supported by the large-scale shell model calculation.
ABSTRACT We present very deep CCD spectrum of the bright, medium-excitation planetary nebula NGC7009, with a wavelength coverage from 3040 to 11000Å. Traditional emission line identification is ...carried out to identify all the emission features in the spectra, based on the available laboratory atomic transition data. Since the spectra are of medium resolution, we use multi-Gaussian line profile fitting to deblend faint blended lines, most of which are optical recombination lines (ORLs) emitted by singly ionized ions of abundant second-row elements such as C, N, O and Ne. Computer-aided emission-line identification, using the code emili developed by Sharpee et al., is then employed to further identify all the emission lines thus obtained. In total about 1200 emission features are identified, with the faintest ones down to fluxes 10-4 of Hβ. The flux errors for all emission lines, estimated from multi-Gaussian fitting, are presented. Plots of the whole optical spectrum, with identified emission lines labelled, are presented along with the results of multi-Gaussian fits. Of all the properly identified emission lines, permitted lines contribute 81 per cent to the total line number. More than 200 Oii permitted lines are presented, as well as many others from Nii and Neii. Due to its relatively simple atomic structure, Cii presents few lines. Within the flux range 10-2-10-4 Hβ where most permitted lines of Cii, Nii, Oii and Neii fall, the average flux measurement uncertainties are about 10-20per cent. Comparison is also made of the number of emission lines identified in the current work of NGC7009 and those of several other planetary nebulae (PNe) that have been extensively studied in the recent literature, and it shows that our line-deblending procedure increases the total line number significantly, especially for emission lines with fluxes lower than 10-3 of Hβ. Higher resolution is still needed to obtain more reliable fluxes for those extremely faint emission lines, lines of fluxes of the order of 10-5-10-6 of Hβ. Plasma diagnostics using optical forbidden line ratios give an average electron temperature of 10020K, which agrees well with previous results of the same object. The average electron density of NGC7009 derived from optical forbidden line ratios is 4290cm-3. The Oiii λ4959/λ4363 nebular-to-auroral line ratio yields an electron temperature of 9800K. The ratio of the nebular continuum Balmer discontinuity at 3646Å to Hii reveals an electron temperature of 6500K, about 600 K lower than the measurements published in the literature. The Balmer decrement reveals a density of about 3000cm-3. Also derived are electron temperatures from the Hei line ratios, and a value of 5100K from the λ7281/λ6678 ratio is adopted. Utilizing the effective recombination coefficients newly available, we find an electron temperature around 1000K from the Oii ORL spectrum. Thus the general pattern of electron temperatures, Te(Oiii) Te(Hi BJ) Te(Hei) Te(Oii), which is seen in many PNe, is repeated in NGC7009. Far-infrared fine-structure lines, with observed fluxes adopted from the literature, are also used to derive Te and Ne. The Oiii (52 + 88 μm)/λ4959 line ratio gives an electron temperature of 9260K, and the 52 μm/88 μm ratio yields an electron density of 1260cm-3. PUBLICATION ABSTRACT
In Paper I, we presented a deep, long-slit spectrum of the bright Saturn nebula NGC 7009. Numerous permitted lines emitted by the C+, N+, O+ and Ne+ ions were detected. Gaussian profile fitting to ...the spectrum yielded more than 1000 lines, the majority of which are optical recombination lines (ORLs) of heavy-element ions. In the current paper, we present a critical analysis of the rich optical recombination spectrum of NGC 7009, in the context of the bi-abundance nebular model proposed by Liu et al. Transitions from individual multiplets are checked carefully for potential blended lines. The observed relative intensities are compared with the theoretical predictions based on high-quality effective recombination coefficients, now available for the recombination line spectrum of a number of heavy-element ions.
The possibility of plasma diagnostics using the ORLs of various heavy-element ions is discussed in detail. The line ratios that can be used to determine electron temperature are presented for each ion, although there is still a lack of adequate atomic data and some of the lines are still not detected in the spectrum of NGC 7009 due to weakness and/or line blending. Plasma diagnostics based on the N ii and O ii recombination spectra both yield electron temperatures close to 1000 K, which is lower than those derived from the collisionally excited line (CEL) ratios (e.g. the O iii and N ii nebular-to-auroral line ratios; see Paper I for details) by nearly one order of magnitude. The very low temperatures yielded by the O ii and N ii ORLs indicate that they originate from very cold regions. The C2+/H+, N2+/H+, O2+/H+ and Ne2+/H+ ionic abundance ratios derived from ORLs are consistently higher, by about a factor of 5, than the corresponding values derived from CELs. In calculating the ORL ionic abundance ratios, we have used the newly available high-quality effective recombination coefficients, and adopted an electron temperature of ∼1000 K, as given by the ORL diagnostics and as a consequence presumably representing the physical conditions prevailing in the regions where the heavy-element ORLs arise. Measurements of the ultraviolet (UV) and infrared (IR) CELs from the literature are used to calculate CEL ionic abundance ratios when optical data are not available for the ionic species. A comparison of results of plasma diagnostics and abundance determinations for NGC 7009 points to the existence of 'cold', metal-rich (i.e. H-deficient) inclusions embedded in the hot, diffuse ionized gas, first postulated by Liu et al.
At electron temperatures yielded by the N ii and O ii ORLs, the predicted relative intensities of ORLs agree well with the observed values, indicating that the current quantum calculations of the recombination spectra of those two ionic species well represent the recombination processes under nebular conditions. Deviations from the LS coupling, noticed in an earlier quantitative spectroscopy by Liu et al. for the same object, are again confirmed, especially for recombination lines of the 4f-3d transition array. For N ii, as well as for O ii, the ionic abundances derived from different J-resolved transitions within a multiplet, or from the transitions belonging to different multiplets, agree with each other. This is another evidence that the new effective recombination coefficients are reliable. New calculations of the effective recombination coefficients for the Ne ii lines at nebular temperatures and densities are needed.
Summary
What is known and objectives
Tacrolimus (TAC) is widely used as part of immunosuppressive regimens. There is great interindividual variation on the disposition of TAC. The aim of this study ...was to develop a population pharmacokinetic (PPK) model for Chinese liver transplant patients and evaluate genetic polymorphism and other possible factors on the PK parameters. The exposure of TAC is to be estimated through Bayesian modelling.
Methods
A total of 47 sets of rich‐time PK and 1234 conventional therapeutic drug monitoring (TDM) data were collected from 125 Chinese liver transplant patients. The pathophysiological data of these patients were recorded. CYP3A5*3 and ABCB1 genotypes were determined for each patient. The PPK model for TAC was established by nonlinear mixed‐effects modelling (nonmem). The impact of pathophysiology and genotype on PPK parameters was evaluated. Bayesian estimators for the area under concentration‐time curve (AUC) of TAC were validated.
Results
A two‐compartment model with lag time was found to be the most suitable model for the pooled full PK and TDM data for Chinese liver transplant patients. The CL/F, V2/F, Q/F, V3/F, Ka and lag time were 17.4±0.81 L/h, 165±44.1 L, 54.9±25.8L/h, 594±87.5 L, 0.51±0.095 L/h and 1.57±0.34 h. Post‐operative day (POD), creatinine clearance (CLcr) and ABCB1 C3435T genotypes were found to have significant influences on CL/F (P<.01). ABCB1 C3435T genotypes showed a significant correlation with V2/F (P<.01). C0–C2 and C0–C2–C4 were shown to be suitable for the estimation of AUC in Chinese liver transplant patients.
What is new and conclusion
A PPK model for TAC was established successfully in Chinese liver transplant patients. POD, CLcr and ABCB1 C3435T genotypes were shown to have significant effects on CL/F. The AUC of TAC in Chinese liver transplant patients could be estimated through Bayesian modelling, based on which individualized immunosuppressive regimens can be designed.
Visual predictive check based on the final model in patients with ABCB1 CC (A), CT (B) and TT (C) genotypes. A population pharmacokinetic (PPK) model for tacrolimus (TAC) was established successfully based on 47 sets of rich time PK and 1234 conventional therapeutic drug monitoring (TDM) data Chinese liver transplant patients. ABCB1 C3435T genotypes were shown to have significant effects on CL/F. The area under concentration‐time curve (AUC) of TAC in Chinese liver‐transplant patients could be estimated through Bayesian modelling, based on which individualized immunosuppressive regimens can be designed.
ABSTRACT
High time resolution and accuracy are of critical importance in the studies of timing analysis and time delay localization of gamma-ray bursts (GRBs), soft gamma-ray repeaters (SGRs) and ...pulsars. The Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) consisting of two micro-satellites, GECAM-A and GECAM-B, launched on 2020 December 10, is aimed at monitoring and locating X-ray and GRBs all over the sky. To achieve its scientific goals, GECAM is designed to have the highest time resolution (0.1 $\mu {\rm s}$) among all GRB detectors ever flown. Here, we make a comprehensive time calibration campaign including both on-ground and on-orbit tests to derive not only the relative time accuracy of GECAM satellites and detectors, but also the absolute time accuracy of GECAM-B. Using the on-ground calibration with a $\rm ^{22}Na$ radioactive source, we find that the relative time accuracy between GECAM-A and GECAM-B is about 0.15 $\mu {\rm s}$ (1σ). To measure the relative time accuracy between all detectors of a single GECAM satellite, cosmic-ray events detected on orbit are utilized since they could produce many secondary particles simultaneously record by multiple detectors. We find that the relative time accuracy among all detectors onboard GECAM-B is about 0.12 $\mu {\rm s}$ (1σ). Finally, we use the novel Li-CCF method to perform the absolute time calibration with Crab pulsar and SGR J1935+2154, both of which were jointly observed by GECAM-B and Fermi/GBM, and obtain that the time difference between GECAM-B and Fermi/GBM is 3.06 ± 6.04 $\mu {\rm s}$ (1σ).
Abstract
In this paper, the multiwavelength data from radio to X-ray bands for 2709 blazars in the 4FGL-DR3 catalog are compiled to calculate their spectral energy distributions using a parabolic ...equation
log
(
ν
f
ν
)
=
P
1
log
ν
−
P
2
2
+
P
3
. Some important parameters including spectral curvature (
P
1
), synchrotron peak frequency (
P
2
,
log
ν
p
), and peak luminosity (
log
L
p
) are obtained. Based on those parameters, we discussed the classification of blazars using the “Bayesian classification” and investigated some mutual correlations. We came to the following results. (1) Based on the Bayesian classification of synchrotron peak frequencies, the 2709 blazars can be classified into three subclasses, i.e.,
log
(
ν
p
/
Hz
)
<
13.7
for low synchrotron peak blazars (LSPs),
13.7
<
log
(
ν
p
/
Hz
)
<
14.9
for intermediate synchrotron peak blazars (ISPs), and
log
(
ν
p
/
Hz
)
>
14.9
for high synchrotron peak blazars (HSPs), and there are 820 HSPs, 750 ISPs, and 1139 LSPs. (2) The
γ
-ray emission has the closest relationship with radio emission, followed by optical emission, while the weakest relationship is that with X-ray emission. The
γ
-ray luminosity is also correlated with the synchrotron peak luminosity. (3) There are strong positive correlations between the curvature (1/∣
P
1
∣) and the peak frequency (
log
ν
p
) for all subclasses (FSRQs, (high, intermediate, and low) BL Lacertae objects). For different subclasses, the correlation slopes are different, which implies that there are different acceleration mechanisms and emission processes for different subclasses of blazars.
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