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Narrow optical resonances of atoms or molecules have immense significance in various precision measurements, such as testing fundamental physics and the generation of primary frequency standards. In these studies, accurate transition centers derived from fitting the measured spectra are demanded, which critically rely on the knowledge of spectral line profiles. Here, we propose a new mechanism of Fano-like resonance induced by distant discrete levels %in atoms or molecules and experimentally verify it with Doppler-free spectroscopy of vibration-rotational transitions of CO$_2$. The observed spectrum has an asymmetric profile and its amplitude increases quadratically with the probe laser power. Our results facilitate a broad range of topics based on narrow transitions. %, such as optical clocks, determination of fundamental physical constants, and quantum memory., 6 pages, 4 figures

We report on a two-fold increase of the $^{39}Ar$ loading rate in an atom trap by enhancing the generation of metastable atoms in a discharge source. Additional atoms in the metastable $1s_5$ level (Paschen notation) are obtained via optically pumping both the $1s_4$ - $2p_6$ transition at 801 nm and the $1s_2$ - $2p_6$ transition at 923 nm. By solving the master equation for the corresponding six-level system, we identify these two transitions to be the most suitable ones and encounter a transfer process between $1s_2$ and $1s_4$ when pumping both transitions simultaneously. We calculate the previously unknown frequency shifts of the two transitions in $^{39}Ar$ and confirm the results with trap loading measurements. The demonstrated increase in the loading rate enables a corresponding decrease in the required sample size, uncertainty and measurement time for $^{39}Ar$ dating, a significant improvement for applications such as dating of ocean water and alpine ice cores., arXiv admin note: text overlap with arXiv:2005.11056

Information about molecular collisions is encoded in the shapes of collision-perturbed molecular resonances. This connection between molecular interactions and line shapes is most clearly seen in simple systems, such as the molecular hydrogen perturbed by a noble gas atom. We study the H2–Ar system by means of highly accurate absorption spectroscopy and ab initio calculations. On the one hand, we use the cavity-ring-down-spectroscopy technique to record the shapes of the S(1) 3-0 line of molecular hydrogen perturbed by argon. On the other hand, we simulate the shapes of this line using ab initio quantum-scattering calculations performed on our accurate H2–Ar potential energy surface (PES). In order to validate the PES and the methodology of quantum-scattering calculations separately from the model of velocity-changing collisions, we measured the spectra in experimental conditions in which the influence of the latter is relatively minor. In these conditions, our theoretical collision-perturbed line shapes reproduce the raw experimental spectra at the percent level. However, the collisional shift, δ0, differs from the experimental value by 20%. Compared to other line-shape parameters, collisional shift displays much higher sensitivity to various technical aspects of the computational methodology. We identify the contributors to this large error and find the inaccuracies of the PES to be the dominant factor. With regard to the quantum scattering methodology, we demonstrate that treating the centrifugal distortion in a simple, approximate manner is sufficient to obtain the percent-level accuracy of collisional spectra.

The (30012) ← (00001) band of

Sub-Doppler saturated absorption spectroscopy of rovibrational transitions of carbon monoxide broadened by nitrogen was recorded at low pressures (1-24 Pa) near 1.56 µm with comb-locked cavity ring-down saturation spectroscopy. We found a nonlinear pressure dependence of the Lamb-dip width of the CO transition induced by elastic scattering. Analysis of the results allows us to characterize parameters of elastic- and nonelastic- scattering under collisions. The elastic scattering angle for nitrogen-induced collisions (CO-N2) was determined to be larger than 0.6 × 10−3 rad. The line broadening of the Lamb dip in the region of low pressures exceeds the broadening at high pressures by a factor of 4 and 5 for the self- and N2-broadening CO R(9) transition. Moreover, much smaller line shifts for both self- and N2-broaden Lamb dips were observed, which was also attributed to the decrease in the number of scattered molecules in the interaction and the increasing attracting forces.

We report on the results of a multiwavelength monitoring campaign of the bright, nearby Seyfert galaxy, Ark 120 using a ~50-day observing programme with Swift and a ~4-month co-ordinated ground-based observing campaign, predominantly using the Skynet Robotic Telescope Network. We find Ark 120 to be variable at all optical, UV, and X-ray wavelengths, with the variability observed to be well-correlated between wavelength bands on short timescales. We perform cross-correlation analysis across all available wavelength bands, detecting time delays between emission in the X-ray band and the Swift V, B and UVW1 bands. In each case, we find that the longer-wavelength emission is delayed with respect to the shorter-wavelength emission. Within our measurement uncertainties, the time delays are consistent with the \tau ~ \lambda^{4/3} relation, as predicted by a disc reprocessing scenario. The measured lag centroids are \tau_{cent} = 11.90 +/- 7.33, 10.80 +/- 4.08, and 10.60 +/- 2.87 days between the X-ray and V, B, and UVW1 bands, respectively. These time delays are longer than those expected from standard accretion theory and, as such, Ark 120 may be another example of an active galaxy whose accretion disc appears to exist on a larger scale than predicted by the standard thin-disc model. Additionally, we detect further inter-band time delays: most notably between the ground-based I and B bands (\tau_{cent} = 3.46 +/- 0.86 days), and between both the Swift XRT and UVW1 bands and the I band (\tau_{cent} = 12.34 +/- 4.83 and 2.69 +/- 2.05 days, respectively), highlighting the importance of co-ordinated ground-based optical observations., Comment: 15 pages, 9 figures, 4 tables; accepted for publication in MNRAS

The ionization energy of ortho-H_{2} has been determined to be E_{I}^{o}(H_{2})/(hc)=124 357.238 062(25) cm^{-1} from measurements of the GK(1,1)-X(0,1) interval by Doppler-free, two-photon spectroscopy using a narrow band 179-nm laser source and the ionization energy of the GK(1,1) state by continuous-wave, near-infrared laser spectroscopy. E_{I}^{o}(H_{2}) was used to derive the dissociation energy of H_{2}, D_{0}^{N=1}(H_{2}), at 35 999.582 894(25) cm^{-1} with a precision that is more than one order of magnitude better than all previous results. The new result challenges calculations of this quantity and represents a benchmark value for future relativistic and QED calculations of molecular energies.

We present a multi-wavelength spectral and temporal investigation of OJ 287 emission during its strong optical-to-X-ray activity between July 2016 - July 2017. The daily $��$-ray fluxes from \emph{Fermi}-LAT are consistent with no variability. The strong optical-to-X-ray variability is accompanied by a change in power-law spectral index of the X-ray spectrum from $< 2$ to $>2$, with variations often associated with changes in optical polarization properties. Cross-correlations between optical-to-X-ray emission during four continuous segments show simultaneous optical-ultraviolet (UV) variations while the X-ray and UV/optical are simultaneous only during the middle two segments. In the first segment, the results suggest X-rays lag the optical/UV, while in the last segment X-rays lead by $\sim$ 5-6 days. The last segment also shows a systematic trend with variations appearing first at higher energies followed by lower energy ones. The LAT spectrum before the VHE activity is similar to preceding quiescent state spectrum while it hardens during VHE activity period and is consistent with the extrapolated VHE spectrum during the latter. Overall, the broadband spectral energy distributions (SEDs) during high activity periods are a combination of a typical OJ 287 SED and an HBL SED, and can be explained in a two-zone leptonic model, with the second zone located at parsec scales, beyond the broad line region, being responsible for the HBL-like spectrum. The change of polarization properties from systematic to chaotic and back to systematic, before, during and after the VHE activity, suggest dynamic roles for magnetic fields and turbulence., 13 pages, 4 figures, 2 tables, MNRAS accepted version

The ionization energy of ortho-H_{2} has been determined to be E_{I}^{o}(H_{2})/(hc)=124 357.238 062(25) cm^{-1} from measurements of the GK(1,1)-X(0,1) interval by Doppler-free, two-photon spectroscopy using a narrow band 179-nm laser source and the ionization energy of the GK(1,1) state by continuous-wave, near-infrared laser spectroscopy. E_{I}^{o}(H_{2}) was used to derive the dissociation energy of H_{2}, D_{0}^{N=1}(H_{2}), at 35 999.582 894(25) cm^{-1} with a precision that is more than one order of magnitude better than all previous results. The new result challenges calculations of this quantity and represents a benchmark value for future relativistic and QED calculations of molecular energies.

We report on a recent multi-band optical photometric and polarimetric observational campaign of the blazar OJ 287 which was carried out during September 2016 -- December 2017. We employed nine telescopes in Bulgaria, China, Georgia, Japan, Serbia, Spain and the United States. We collected over 1800 photometric image frames in BVRI bands and over 100 polarimetric measurements over ~175 nights. In 11 nights with many quasi-simultaneous multi-band (V, R, I) observations, we did not detect any genuine intraday variability in flux or color. On longer timescales, multiple flaring events were seen. Large changes in color with respect to time and in a color--magnitude diagram were seen, and while only a weak systematic variability trend was noticed in color with respect to time, the color--magnitude diagram shows a bluer-when-brighter trend. Large changes in the degree of polarization, and substantial swings in the polarization angle were detected. The fractional Stokes parameters of the polarization showed a systematic trend with time in the beginning of these observations, followed by chaotic changes and then an apparently systematic variation at the end. These polarization changes coincide with the detection and duration of the source at very high energies as seen by VERITAS. The spectral index shows a systematic variation with time and V-band magnitude. We briefly discuss possible physical mechanisms that could explain the observed flux, color, polarization, and spectral variability., Comment: 16 pages, 8 figures, 7 tables; Accepted for Publication to AJ

The 2 ^{3}S-2 ^{3}P transition of ^{4}He was measured by comb-linked laser spectroscopy using a transverse-cooled atomic beam. The centroid frequency was determined to be 276 736 495 600.0(1.4) kHz, with a fractional uncertainty of 5.1×10^{-12}. This value is not only more accurate but also differs by as much as -49.5 kHz (20σ) from the previous result given by [Cancio Pastor et al., Phys. Rev. Lett. 92, 023001 (2004)PRLTAO0031-900710.1103/PhysRevLett.92.023001; Cancio Pastor et al.Phys. Rev. Lett.97, 139903(E) (2006)10.1103/PhysRevLett.97.139903; Cancio Pastor et al.Phys. Rev. Lett.108, 143001 (2012)10.1103/PhysRevLett.108.143001]. In combination with ongoing theoretical calculations, this work may allow the most accurate determination of the nuclear charge radius of helium.

Although a patchwork of projects shows a process of agriculture intensification in North China during the Neolithic, the impact of cereal farming on animal husbandry and their mutual interaction remain cloudy. This study reports bone collagen δ13C and δ15N of humans and animals from Wayaogou (ca 6.5–6.0 kyrs bp) and Dongying (ca 5.9–5.6 kyrs bp, 4.6–4.0 kyrs bp) to explore temporal trend of livestock raising and particularly the importance of millet fodder to stock raising practices in the Wei River valley, North China. The isotopic evidence overall shows that millet products increased in human and domestic animal diets during the mentioned chronological span. δ13C values of pigs and dogs at Dongying are higher than those at Wayaogou, implying that the importance of millet nutrients increased to animal husbandry diachronically. Interestingly, δ13C results of domestic cattle of Dongying late phase (−14.1 ± 1.1‰, N = 5) are more enriched than Wayaogou wild Bos (−17.8 ± 0.3‰, N = 3), indicating that millet fodder had taken a significant place in early cattle husbandry. Besides, differences between Bos species of the two periods also imply that δ13C values of bone collagen constitute a potential indicator for tracing the origin of cattle husbandry in North China. In addition, domestic sheep at Dongying produced similar isotope data to wild ovicaprid at Wayaogou, suggesting that they possibly had grazed for the most in grassland and therefore experienced a different lifestyle from cattle. Copyright © 2013 John Wiley & Sons, Ltd.

The fine-structure splitting in the 2^{3}P_{J} (J=0, 1, 2) levels of ^{4}He is of great interest for tests of quantum electrodynamics and for the determination of the fine-structure constant α. The 2^{3}P_{0}-2^{3}P_{2} and 2^{3}P_{1}-2^{3}P_{2} intervals are measured by laser spectroscopy of the ^{3}P_{J}-2^{3}S_{1} transitions at 1083 nm in an atomic beam, and are determined to be 31 908 130.98±0.13 kHz and 2 291 177.56±0.19 kHz, respectively. Compared with calculations, which include terms up to α^{5}Ry, the deviation for the α-sensitive interval 2^{3}P_{0}-2^{3}P_{2} is only 0.22 kHz. It opens the window for further improvement of theoretical predictions and an independent determination of the fine-structure constant α with a precision of 2×10^{-9}.

Effects of exogenous putrescine and calcium on growth, membrane permeability and ion assimilation of strawberry seedlings under 150 mmol L -1 NaCl stress were studied. The growth was inhibited, and shoot fresh weight, dry weight and root fresh weight, dry weight were all decreased under NaCl stress. The salt damage index was 40%. The increased membrane was also observed in leaf cell of strawberry seedlings under salt stress, in the meanwhile the assimilation of natrium and chlorine increased, which resulted in low K + to Na + ratios and low Ca 2+ to Na + ratios in leaf and root cells. Removing Ca 2+ from the culture solution showed least biomass, maximal membrane damage and chloride (Cl - ) concentration, minimum K + /Na + and Ca 2+ /Na + . Calcium application treatment alleviated the harmful effects of NaCl to seedlings, as manifested by the higher levels of fresh weights and dry weights, the ratio of K + to Na + and that of Ca 2+ to Na + , while the membrane permeability was lower. Putrescine application treatment also alleviated the harmful effects of NaCl to seedlings. In the absence of Ca 2+ , an increased K + to Na + ratio and Ca 2+ to Na + ratio was also observed with exgenous putrescine treatment, but no differences were observed in fresh weight, dry weight and membrane between treated with putrescine and those treated of distilled water in the absence of Ca 2+ These results suggested that Ca 2+ could influence the ability of salt tolerance of strawberry seedlings, the role of putrescine in improving growth and suppressing the assimilation and transport of sodium was promoted by calcium, whereas, it was weakened overall or partly by calcium-deficiency.

Compared with the traditional high-speed video camerameasurement method, ultra-wideband(UWB) technology is valuable in the detection and tracing of debris throw during explosion, due to its distinct advantages such as high positioning accuracy, multipath immunity, and low power consumption. In this pa-per, dielectric properties of Concrete slabs are first measured and used in the design of a slot antenna embed-ded in Concrete. An active UWB tag integrated with the slot antenna is designed for a real-time debris track-ing system. The tag size is 25 × 25 × 25 mm which can be embedded in Concrete. Due to its small size, the tag has high chance to be intact in fragmented Concrete debris in explosion. The tag has low DC power con-sumption of 22.8 mW with output pulse amplitude of 12 V peak to peak (into 50 ohms) resulting in operating range of more than 190 meters.

To explore the long-term prognosis and influence of social support and coping style of patients with post-traumatic stress disorder (PTSD) after suffering from floods.Patients suffered PTSD due to Dongting lake flood in 1998 were selected through cluster random sampling. PTSD scale civilian version (PCL-C) was used to examine and diagnose the participants in this study. PTSD was then evaluated by the social support rating scale (SSRS) and the simple coping style questionnaire (SCSQ).Among all the 120 subjects, 14(11.67%) of them were diagnosed as having PTSD. Compared with the rehabilitation group, scores on subjective support, objective support, total social support and positive coping, total of coping style from the non-rehabilitation group all appeared significant low (P0.05). Data from the multivariate logistic regression showed that social support (OR=0.281, 95% CI: 0.117-0.678) and coping style (OR= 0.293, 95% CI: 0.128-0.672) were protective factors of the chronic PTSD after the floods while disaster experience (OR=1.626, 95%CI: 1.118-2.365) appeared as a risk factor.Chronic PTSD developed after the floods called for attention. Better social support, positive coping style could significantly improve the long-term prognosis of patients with PTSD after the floods.

Melt of NaCO3 can favor oxidation of Zr to form ZrO2 thin film on Zr surface, which is used to make Zr/ZrO2 oxidation/reduction electrode of pH sensor for testing elevated temperature aqueous solutions. Using SEM, EPMA, XPS, EXAFS and HRTEM, we found that ZrO2 film is tightness and solid with 20 μm thickness composed by nanometer-sized monoclinic crystals. Zr/ZrO2 interface is characterized of zoning structure according to topography and chemical composition in five zones: oxygen-rich ZrO2, ZrO2, oxygen-rich Zr metal, oxygen-bearing Zr and Zr from outmost to center. Melt oxidation process of Zr involved oxidation time, air and temperature. The air is important effect on structural and electrochemical properties of ZrO2 thin film for making elevate temperature electrochemical sensor. If oxygen air largely presented in carbonate melting process, ZrO2 thin film is not tightness and not for oxidation/reduction electrode.

Neutron activation analysis (NAA) and synchrotron radiation X-ray fluorescence analysis (SRXRF) were used to study the loss and recuperation of inorganic elements of osteoporotic rat bone and the effects of Zhugu Capsule. The results of the animal experiments showed that there was greater loss of multiple elements in cancellous bone than in cortical bone that was difficult to be improved. Yet in the mid-shaft femur, which is mainly consisted of cortical bone, the contents of multiple elements were notably recuperated. Zhugu Capsule could increase the content of not only of Ca, but also Zn and Sr. Further, it could also improve the distribution of these elements in femur.

In this paper, a low-pass filter (LPF) with a uniplanar compact electromagnetic band-gap (UC-EBG) structure in the ground plane is investigated. The finite-difference time-domain (FDTD) method combined with the modified matrix pencil (MMP) method is applied to analyze this complicated structure. A short segment of an FDTD record is used to train the MMP predictor, and an accurate future realization can be obtained. The numerical simulation for low-pass filters with UC-EBG demonstrates that the efficiency of the FDTD method can be improved by up to 70%. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 44: 37–41, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20540

This paper presents a new combination of the finite-difference time-domain (FDTD) method and the least-squares support vector machines (LS-SVM) technique. The LS-SVM is a statistical-learning method which has a self-contained basis of statistical-learning theory and excellent learning performance. A short segment of an FDTD record is used to train the LS-SVM predictor in order to obtain an accurate future realization. Numerical simulations for two typical microwave filters demonstrate that the LS-SVM method can achieve good forecasting accuracy and the efficiency of the FDTD method can be improved by up to 70%. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 44: 296–299, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20615

Context. The international whole earth blazar telescope (WEBT) consortium planned and carried out three days of intensive micro-variability observations of S5 0716+714 from February 22, 2009 to February 25, 2009. This object was chosen due to its bright apparent magnitude range, its high declination, and its very large duty cycle for micro-variations. Aims. We report here on the long continuous optical micro-variability light curve of 0716+714 obtained during the multi-site observing campaign during which the Blazar showed almost constant variability over a 0.5 magnitude range. The resulting light curve is presented here for the first time. Observations from participating observatories were corrected for instrumental diff?erences and combined to construct the overall smoothed light curve. Methods. Thirty-six observatories in sixteen countries participated in this continuous monitoring program and twenty of them submitted data for compilation into a continuous light curve. The light curve was analyzed using several techniques including Fourier transform, Wavelet and noise analysis techniques. Those results led us to model the light curve by attributing the variations to a series of synchrotron pulses. Results. We have interpreted the observed microvariations in this extended light curve in terms of a new model consisting of individual stochastic pulses due to cells in a turbulent jet which are energized by a passing shock and cool by means of synchrotron emission. We obtained an excellent fit to the 72-hour light curve with the synchrotron pulse model.

The secondary structure of the C-terminal fragment (10 kDa) of rat hsc70 (a. a. #546–646) was analyzed according to circular dichroism spectra. In the pH range 5–9 and at concentrations of Na+ up to 0.18 M, the protein is estimated to contain 32-34% a helix, 18–16% of β sheet, approximately 25% for both turns and disordered structures. This protein is most stable at pH between 6 and 7 in solution with 0.055 M Na+ concentration. However, all Tm are relatively large (57–73 °C) and alterations from one condition to another are small. Thus, the C-fragment (10 kDa) of hsc70 is a stably folded protein under physiological conditions.

The existence and stability of defect solitons in optical lattices with parity-time (PT) symmetric defect are reported. For positive or zero defects, in-phase solitons and out of phase solitons can exist stably in the semi-infinite gap and the first gap, respectively. For negative defects, in-phase solitons can be stable in both the semi-infinite gap and the first gap, whereas out of phase solitons are unstable in the first gap. For in-phase solitons with positive defect in the semi-infinite gap and negative defect in the first gap, there exists a cutoff point of the propagation constant below which the defect solitons vanish. The imaginary parts of the PT-symmetric defect potentials deeply affect the stability of solitons.

The $S$(3) electric-quadrupole transition of the (3-0) overtone of molecular hydrogen has been recorded with a continuous-wave cavity ring-down spectrometer and calibrated with sub-megahertz accuracy using a temperature-stabilized Fabry-P\'erot interferometer. The collision-induced frequency shift and the frequency at zero pressure limit are derived from a fit of the spectral profiles. The absolute transition frequency of the $S$(3) line is determined to be 376 531 818.1 MHz with a 1.6-MHz accuracy ($\ensuremath{\delta}\ensuremath{\nu}/\ensuremath{\nu}=4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}9}$) by measuring the shift to a Rb line at 795 nm. As the best determined transition frequency of neutral H${}_{2}$ in the ground electronic state, this value agrees well with recent high-level quantum chemistry calculations including relativistic and quantum electrodynamics corrections.

Sj16, a 16-kDa protein produced by Schistosoma japonicum, has been demonstrated to have anti-inflammatory effect. However, the possible mechanism of these phenomena has not been discovered. Here, we tried to touch it with arthritis rats' model induced by injection of complete Freund's adjuvant (CFA). A set of pathogenic characters were observed in CFA-treated rat, including local and systematic read-out, which showed the model successfully set up. After administration of rSj16 (recombinant Sj16) in vivo, paw swelling reduced significantly and in a dose-dependent manner, the level of TNF-α, IL-1β and NO decreased and IL-10 in the serum increased. In vitro, rSj16 reversed the augmented surface expression of CD80, CD86, CD54 and OX6 induced by lipopolysaccharide (LPS) in bone marrow-derived DCs (BMDCs), whereas endocytotic capacity of rSj16-treated dendritic cell (DC) was profoundly increased. IL-12p70 released from rSj16-treated BMDC was decreased but IL-10 increased. Further, following incubation with rSj16 primed BMDCs, the sensitized T cells exhibited increased production of anti-inflammatory IL-10 and IL-4 and decreased production of IL-12p70 and IFN-γ. Collectively, these results implied that rSj16 alleviated CFA-induced arthritis, and the possible mechanisms may be its interruption of maturation and function of DCs. rSj16 could be a potential therapeutic agent against rheumatoid arthritis.

Overwhelming evidence has been accumulated since 1914 that diffusion in silicon takes place via a dual vacancy-interstitialcy mechanism. Most of the ensuing discoveries of new phenomena and the further sophistication of the dual vacancy-interstitialcy diffusion model are related to nonequilibrium point defects. Many sources of excess silicon interstitials and excess vacancies have been discovered; but the mechanisms of defect generation, particularly by surface sources, have remained unresolved issues

The silicon integrated‐circuits chip is built by contiguously embedding, butting, and overlaying structural elements of a large variety of materials of different elastic and thermal properties. Stress develops in the thermal cycling of the chip. Furthermore, many structural elements such as CVD (chemical vapor deposition) silicon nitride, silicon dioxide, polycrystalline silicon, etc., by virtue of their formation processes, exhibit intrinsic stresses. Large localized stresses are induced in the silicon substrate near the edges and corners of such structural elements. Oxidation of nonplanar silicon surfaces produces another kind of stress that can be very damaging, especially at low oxidation temperatures. Mismatch of atomic sizes between dopants and the silicon, and heteroepitaxy produce another class of strain that can lead to the formation of misfit dislocations. Here we review the achievements to date in understanding and modeling these diverse stress problems.

The aim of this study is to develop new pH sensors that can be used to test and monitor hydrogen ion activity in hydrothermal conditions. A Zr/ZrO2 oxidation electrode is fabricated for in situ pH measurement of high-temperature aqueous solutions. This sensor responds rapidly and precisely to pH over a wide range of temperature and pressure. The Zr/ZrO2 electrode was made by oxidizing zirconium metal wire with Na2CO3 melt, which produced a thin film of ZrO2 on its surface. Thus, an oxidation-reduction electrode was produced. The Zr/ZrO2 electrode has a good electrochemical stability over a wide range of pH in high-temperature aqueous solutions when used with a Ag/AgCl reference electrode. Measurements of the Zr/ZrO2 sensor potential against a Ag/AgCl reference electrode is shown to vary linearly with pH between temperatures 20 and 200 degrees C. The slope of the potential versus pH at high temperature is slightly below the theoretical value indicated by the Nernst equation; such deviation is attributed to the fact that the sensor is not strictly at equilibrium with the solution to be tested in a short period of time. The Zr/ZrO2 sensor can be calibrated over the conditions that exist in the natural deep-seawater. Our studies showed that the Zr/ZrO2 electrode is a suitable pH sensor for the hydrothermal systems at midocean ridge or other geothermal systems with the high-temperature environment. Yttria-stabilized zirconia sensors have also been used to investigate the pH of hydrothermal fluids in hot springs vents at midocean ridge. These sensors, however, are not sensitive below 200 degrees C. Zr/ZrO2 sensors have wider temperature range and can be severed as good alternative sensors for measuring the pH of hydrothermal fluids.

Stress from isolation trenches in silicon integrated circuits has been studied using an analytical solution that the author recently obtained for the stress problem of a parallelepipedic inclusion in a three‐dimensional semispace. The origin of the stress is assumed to be the thermal mismatch between the trench fill and the silicon substrate, or equivalently the intrinsic stress of the trench fill. The effect of various trench parameters such as the trench length, width, and depth, as well as the proximity to other trenches, are investigated for a number of cases. The results are shown for all stress components in order to provide an insight into the characteristics of the trench‐induced stress. There are some surprises: Some examples are the existence of a tensile pocket in the stress component normal to the trench side, and that stress components both normal and parallel to the trench increase greatly in intensity as the trench becomes shorter.

In this paper, a novel low-pass filter with the UC-EBG structure in the ground plane is investigated. The numerical simulation of our novel filter shows an intrinsic stop-band at harmonic frequencies. We adopt a combination of FDTD method and matrix pencil method (MP) to analyze this complicated structure. A short segment of an FDTD records is used to train the MP predictor, and an accurate future realization can be obtained. Numerical simulating for several microwave circuits with UC-EBG based on the combination technique demonstrate with numerical results that the efficiency of the FDTD method can be improved by up to 70%.

We consider a model of stress‐driven void growth in interconnection lines that are narrower than the metal grain size. The metal line is imbedded in an SiO2 matrix at a temperature T0, and incurs tensile stress after being brought down to an annealing temperature Tann. A void nucleates at a particular grain boundary, along which the diffusion is assumed to be so fast that the stress relaxation at that grain boundary is nearly complete in a very short time. This is assumed to occur before the void spans the width of the line. Thereafter, the void continues to grow by matter transport through bulk diffusion, cascading down sequential tiers of grain boundaries, resulting in a layer of extra matter at each grain boundary for strain relaxation. The kinetics of the void growth is given analytically. The consideration of climbing dislocations is deferred for future analysis.

An expression is derived for the critical thickness of heteroepitaxial films by taking the energy minimization approach. It is exactly identical to the critical thickness obtained by Matthew and Blakeslee [J. Cryst. Growth 27, 118 (1974)] using a force balance approach, after allowing for a discrepancy judged to be an unmentioned approximation in the latter. The equivalence of the two formulations is explained conceptually. The reason is pointed out for the very different critical thickness obtained by People and Bean [Appl. Phys. Lett. 47, 322 (1985); 49, 229 (1986)] using the energy minimization approach. It is further shown that misfit dislocations do not appear en masse catastrophically when the critical thickness is reached. Rather, their density increases gradually with the epitaxial thickness, approaching only asymptotically a value required for a complete relief of film stress as the thickness tends to infinity. Any observed sudden mass appearance of misfit dislocations must be attributed to a sub...

The radial and ulnar bone mineral content (BMC) was measured by single-photon absorptiometry, and the effects of multiple independent variables on BMC and bone width (BW) were explored using multiple regression analysis in 332 rural and city children aged 0-16 years in Henan province from 1994 to 1995. BMC, BW, BMC/BW and forearm length increased with age increasing, and the BMC in city children aged 0-6 years was higher than that in rural children. Radial BMC was positively related to BW in the measured sites. Age, body weight and height (or length) all had significantly positive and independent effects on radial BMC in both groups. The positive correlation of radial BMC with age was observed, however, the ratio of radial BMC to body weight was negative correlation. The BW in measured site and forearm length increased with ages. After adjusted for body size, there were no significant effects of sex, age and body weight on radial BW except height (length). This study shows that overall body size rather than adiposity is the important factor for bone BMC, so that it is needed to consider several variables, for example, BMC, BMD, BMC/body weight and BMC/age.

Atom trap trace analysis, a laser-based atom counting method, has been applied to analyze atmospheric 39Ar (half-life=269 yr), a cosmogenic isotope with an isotopic abundance of 8×10(-16). In addition to the superior selectivity demonstrated in this work, the counting rate and efficiency of atom trap trace analysis have been improved by 2 orders of magnitude over prior results. The significant applications of this new analytical capability lie in radioisotope dating of ice and water samples and in the development of dark matter detectors.

The paper determined the activity of mitogenic response of T lymphocyte, NK cell activity and lymphocyte IL-2 production activity after the mice had been exposed to the polluted kitchen air. The results showed that these immune functions were inhibited in descending order in the mice exposed to pollutants from burning coal mixed with oily smoke.