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Dataset for publication "Magma Ocean Depth Controls Fe Isotope Fractionation Between Mantle and Core." Including experimental conditions, major element composition and ferric iron content of the initial glasses, Mossbaur results, and NRIXS results generated in this study.

We report on the impact of magnetoelastic coupling on the magnetocaloric properties of LaFe11.4Si1.6H1.6 in terms of the vibrational density of states, which we determined with 57Fe nuclear resonant inelastic X-ray scattering measurements and with density-functional-theory based first-principles calculations in the ferromagnetic low-temperature and paramagnetic high-temperature phase. In experiments and calculations, we observe pronounced differences in the shape of the Fe-partial VDOS between non-hydrogenated and hydrogenated samples. This shows that hydrogen does not only shift the temperature of the first-order phase transition, but also affects the elastic response of the Fe-subsystem significantly. In turn, the anomalous redshift of the Fe VDOS, observed by going to the low-volume PM phase, survives hydrogenation. As a consequence, the change in the Fe specific vibrational entropy ΔSlat across the phase transition has the same sign as the magnetic and electronic contribution. DFT calculations show that the same mechanism, which is a consequence of the itinerant electron metamagnetism associated with the Fe subsystem, is effective in both the hydrogenated and he hydrogen-free compounds. Although reduced by 50 % as compared to the hydrogen-free system, the measured change ΔSlat of 3.2\pm1.9 J/kgK across the FM to PM transition contributes with 35 % significantly and cooperatively to the total isothermal entropy change ΔSiso. Hydrogenation is observed to induce an overall blueshift of the Fe-VDOS with respect to the H-free compound; this effect, together with the enhanced Debye temperature observed, is a fingerprint of the hardening of the Fe sublattice by hydrogen incorporation. In addition, the mean Debye velocity of sound of LaFe11.4Si1.6H1.6 was determined from the NRIXS and the DFT data.

We report on the impact of magnetoelastic coupling on the magnetocaloric properties of LaFe$_{11.4}$Si$_{1.6}$H$_{1.6}$ in terms of the vibrational density of states, which we determined with $^{57}$Fe nuclear resonant inelastic X-ray scattering measurements and with density-functional-theory based first-principles calculations in the ferromagnetic low-temperature and paramagnetic high-temperature phase. In experiments and calculations, we observe pronounced differences in the shape of the Fe-partial VDOS between non-hydrogenated and hydrogenated samples. This shows that hydrogen does not only shift the temperature of the first-order phase transition, but also affects the elastic response of the Fe-subsystem significantly. In turn, the anomalous redshift of the Fe VDOS, observed by going to the low-volume PM phase, survives hydrogenation. As a consequence, the change in the Fe specific vibrational entropy $\Delta S_\mathrm{lat}$ across the phase transition has the same sign as the magnetic and electronic contribution. DFT calculations show that the same mechanism, which is a consequence of the itinerant electron metamagnetism associated with the Fe subsystem, is effective in both the hydrogenated and he hydrogen-free compounds. Although reduced by 50 % as compared to the hydrogen-free system, the measured change $\Delta S_\mathrm{lat}$ of 3.2\pm1.9 J/kgK across the FM to PM transition contributes with 35 % significantly and cooperatively to the total isothermal entropy change $\Delta S_\mathrm{iso}$. Hydrogenation is observed to induce an overall blueshift of the Fe-VDOS with respect to the H-free compound; this effect, together with the enhanced Debye temperature observed, is a fingerprint of the hardening of the Fe sublattice by hydrogen incorporation. In addition, the mean Debye velocity of sound of LaFe$_{11.4}$Si$_{1.6}$H$_{1.6}$ was determined from the NRIXS and the DFT data., Comment: 13 pages 9 figures

Low-permeability low-pressure fractured reservoirs in Ordos Basin have low water flooding recovery factors, while CO2 core flooding experiments are limited, the visualization of CO2 flooding physical simulation experiment still being in the blank state, CO2 flooding visualised experiments have been conduct by using specialized ultra-low permeability sandstone microcosmic models to observe flow characteristics of CO2 flooding. The experiment results indicate that: ① in the process of CO2 flooding under the supercritical pressure condition, gas–oil interface disappears in the front end, rear-end CO2 is in supercritical state, which enable CO2 to enter into smaller throats and to displace oil thoroughly; ② direct CO2 flooding has better displacement efficiency which is 10% higher than that of CO2 flooding after water flooding; ③ CO2 flooding after water flooding still can improve oil displacement about 10%; ④ CO2 flooding can improve both microscopic displacement efficiencies and macroscopic displacement efficiencies, and formation microscopic pore structure and heterogeneity are important factors which affect the CO2 flooding efficiencies.

The extradiol dioxygenases are a large subclass of mononuclear non-heme Fe enzymes that catalyze the oxidative cleavage of catechols distal to their OH groups. These enzymes are important in bioremediation, and there has been significant interest in understanding how they activate O(2). The extradiol dioxygenase homoprotocatechuate 2,3-dioxygenase (HPCD) provides an opportunity to study this process, as two O(2) intermediates have been trapped and crystallographically defined using the slow substrate 4-nitrocatechol (4NC): a side-on Fe-O(2)-4NC species and a Fe-O(2)-4NC peroxy bridged species. Also with 4NC, two solution intermediates have been trapped in the H200N variant, where H200 provides a second-sphere hydrogen bond in the wild-type enzyme. While the electronic structure of these solution intermediates has been defined previously as Fe(III)-superoxo-catecholate and Fe(III)-peroxysemiquinone, their geometric structures are unknown. Nuclear resonance vibrational spectroscopy (NRVS) is an important tool for structural definition of non-heme Fe-O(2) intermediates, as all normal modes with Fe displacement have intensity in the NRVS spectrum. In this study, NRVS is used to define the geometric structure of the H200N-4NC solution intermediates in HPCD as an end-on Fe(III)-superoxocatecholate and an end-on Fe(III)-hydroperoxo-semiquinone. Parallel calculations are performed to define the electronic structures and protonation states of the crystallographically defined wild-type HPCD-4NC intermediates, where the side-on intermediate is found to be a Fe(III)-hydroperoxo-semiquinone. The assignment of this crystallographic intermediate is validated by correlation to the NRVS data through computational removal of H200. While the side-on hydroperoxo semiquinone intermediate is computationally found to be nonreactive in peroxide bridge formation, it is isoenergetic with a superoxo catecholate species that is competent in performing this reaction. This study provides insight into the relative reactivities of Fe(III)-superoxo and Fe(III)-hydroperoxo intermediates in non-heme Fe enzymes and into the role H200 plays in facilitating extradiol catalysis.

BaFe$_2$S$_3$ is a quasi one-dimensional Mott insulator that orders antiferromagnetically below 117(5)\,K. The application of pressure induces a transition to a metallic state, and superconductivity emerges. The evolution of the magnetic behavior on increasing pressure has up to now been either studied indirectly by means of transport measurements, or by using local magnetic probes only in the low pressure region. Here, we investigate the magnetic properties of BaFe$_2$S$_3$ up to 9.9\,GPa by means of synchrotron $^{57}$Fe M\"ossbauer spectroscopy experiments, providing the first local magnetic phase diagram. The magnetic ordering temperature increases up to 185(5) K at 7.5\,GPa, and is fully suppressed at 9.9\,GPa. The low-temperature magnetic hyperfine field is continuously reduced from 12.9 to 10.3\,T between 1.4 and 9.1\,GPa, followed by a sudden drop to zero at 9.9\,GPa indicating a first-order phase transition. The pressure dependence of the magnetic order in BaFe$_2$S$_3$ can be qualitatively explained by a combination of a bandwidth-controlled insulator-metal transition as well as a pressure enhanced exchange interaction between Fe-atoms and Fe 3\textit{d}-S 3\textit{p} hybridization., Comment: 4 pages, 4 figures

Magnetocaloric LaFe13−xSix-based compounds belong to the outstanding materials with potential for efficient solid-state refrigeration. We have performed temperature-dependent 57Fe nuclear resonant inelastic X-ray scattering measurements (in a field µ0H of ∼ 0.7 T) of the vibrational (phonon) density of states, VDOS, in LaFe11:6Si1:4 across the metamagnetic isostructural first-order phase transition at TC ∼ 192 K from the low-temperature ferromagnetic (FM) to the high-temperature paramagnetic (PM) phase, in order to determine the change in thermodynamic properties of the Fe lattice at TC. The experimental results are compared with density-functional-theory (DFT)-based first-principles calculations using the fixed-spin moment (FSM) approach. Our combined experimental and theoretical results reveal distinct and abrupt changes in the VDOS of the Fe sublattice across TC, occurring within a small temperature interval of ∆T ≤ 12 K around TC. This indicates that strong magnetoelastic coupling (at the atomic scale) is present up to TC, leading to a pronounced lattice softening (phonon red-shift) in the PM phase. These changes originate from the itinerant electron magnetism associated with Fe and are correlated with distinct modifications in the Fe-partial electronic density of states, D(EF ), at the Fermi energy, EF . From the experimental VDOS we can infer an abrupt increase (jump) in the Fe-partial vibrational entropy ∆Svib of + 6.9 ± 2.6 J/(kg K) and in the vibrational specific heat ∆Cvib of + 2.7 ± 1.6 J/(kg K) upon heating. The increase in magnitude of the vibrational entropy |∆Svib |= 6.9 J/(kg K) of the Fe sublattice at TC upon heating is substantial, if compared with the magnitude of the isothermal entropy change |∆Siso| of 14.2 J/(kg K) in a field change ∆B from 0 to 1 T, as obtained from isothermal magnetization measurements on our sample and using the Maxwell relation. We demonstrate that ∆Svib obtained by NRIXS is a sizable quantity and contributes directly and cooperatively to the total entropy change ∆Siso at the phase transition of LaFe13−xSix.

BaFe$_2$S$_3$ is a quasi one-dimensional Mott insulator that orders antiferromagnetically below 117(5)\,K. The application of pressure induces a transition to a metallic state, and superconductivity emerges. The evolution of the magnetic behavior on increasing pressure has up to now been either studied indirectly by means of transport measurements, or by using local magnetic probes only in the low pressure region. Here, we investigate the magnetic properties of BaFe$_2$S$_3$ up to 9.9\,GPa by means of synchrotron $^{57}$Fe M��ssbauer spectroscopy experiments, providing the first local magnetic phase diagram. The magnetic ordering temperature increases up to 185(5) K at 7.5\,GPa, and is fully suppressed at 9.9\,GPa. The low-temperature magnetic hyperfine field is continuously reduced from 12.9 to 10.3\,T between 1.4 and 9.1\,GPa, followed by a sudden drop to zero at 9.9\,GPa indicating a first-order phase transition. The pressure dependence of the magnetic order in BaFe$_2$S$_3$ can be qualitatively explained by a combination of a bandwidth-controlled insulator-metal transition as well as a pressure enhanced exchange interaction between Fe-atoms and Fe 3\textit{d}-S 3\textit{p} hybridization., 4 pages, 4 figures

Online reconstruction of a time-variant quantum state from the encoding/decoding results of quantum communication is addressed by developing a method of evolution reconstruction from a single measurement record with random time intervals. A time-variant two-dimensional state is reconstructed on the basis of recovering its expectation value functions of three nonorthogonal projectors from a random single measurement record, which is composed from the discarded qubits of the six-state protocol. The simulated results prove that our method is robust to typical metro quantum channels. Our work extends the Fourier-based method of evolution reconstruction from the version for a regular single measurement record with equal time intervals to a unified one, which can be applied to arbitrary single measurement records. The proposed protocol of evolution reconstruction runs concurrently with the one of quantum communication, which can facilitate the online quantum tomography.

Mononuclear non-haem iron (NHFe) enzymes catalyse a broad range of oxidative reactions, including halogenation, hydroxylation, ring closure, desaturation and aromatic ring cleavage reactions. They are involved in a number of biological processes, including phenylalanine metabolism, the production of neurotransmitters, the hypoxic response and the biosynthesis of secondary metabolites. The reactive intermediate in the catalytic cycles of these enzymes is a high-spin S = 2 Fe(IV)=O species, which has been trapped for a number of NHFe enzymes, including the halogenase SyrB2 (syringomycin biosynthesis enzyme 2). Computational studies aimed at understanding the reactivity of this Fe(IV)=O intermediate are limited in applicability owing to the paucity of experimental knowledge about its geometric and electronic structure. Synchrotron-based nuclear resonance vibrational spectroscopy (NRVS) is a sensitive and effective method that defines the dependence of the vibrational modes involving Fe on the nature of the Fe(IV)=O active site. Here we present NRVS structural characterization of the reactive Fe(IV)=O intermediate of a NHFe enzyme, namely the halogenase SyrB2 from the bacterium Pseudomonas syringae pv. syringae. This intermediate reacts via an initial hydrogen-atom abstraction step, performing subsequent halogenation of the native substrate or hydroxylation of non-native substrates. A correlation of the experimental NRVS data to electronic structure calculations indicates that the substrate directs the orientation of the Fe(IV)=O intermediate, presenting specific frontier molecular orbitals that can activate either selective halogenation or hydroxylation.

We present phonon dispersions, element-resolved vibrational density of states (VDOS) and corresponding thermodynamic properties obtained by a combination of density functional theory (DFT) and nuclear resonant inelastic X-ray scattering (NRIXS) across the metamagnetic transition of B2 FeRh in the bulk material and thin epitaxial films. We see distinct differences in the VDOS of the antiferromagnetic (AF) and ferromagnetic (FM) phase which provide a microscopic proof of strong spin-phonon coupling in FeRh. The FM VDOS exhibits a particular sensitivity to the slight tetragonal distortions present in epitaxial films, which is not encountered in the AF phase. This results in a notable change in lattice entropy, which is important for the comparison between thin film and bulk results. Our calculations confirm the recently reported lattice instability in the AF phase. The imaginary frequencies at the $X$-point depend critically on the Fe magnetic moment and atomic volume. Analyzing these non vibrational modes leads to the discovery of a stable monoclinic ground state structure which is robustly predicted from DFT but not verified in our thin film experiments. Specific heat, entropy and free energy calculated within the quasiharmonic approximation suggest that the new phase is possibly suppressed because of its relatively smaller lattice entropy. In the bulk phase, lattice degrees of freedom contribute with the same sign and in similar magnitude to the isostructural AF-FM phase transition as the electronic and magnetic subsystems and therefore needs to be included in thermodynamic modeling., 15 pages, 12 figures

It is known theoretically that the long wavelength infrared has better performance when transmitting in atmospheric turbulence. In order to evaluate the influence of the atmospheric turbulence quantificationally, the characteristics of different infrareds transmission in atmospheric turbulence are simulated and studied. A series of time relevant phase screens of atmospheric turbulence are simulated based on Fourier transform method proposed by McGlamery. Wind speed and direction are introduced in the meantime. Wavefront distortion, image spot dancing and spreading, receive loss of different wavelengths (0.85μm, 3.6μm, 10.6μm) are simulated respectively and compared to each other. The results show that the performances of long wavelength infrared (10.6μm) are the best, mid wavelength infrared (3.6μm) takes the second place and short wavelength infrared (0.85μm) is the worst.

The birefringence of fiber quantum channel is compensated for without a reference optical beam always in an interrupt way. We propose and demonstrate a scheme of continuous active polarization compensation based on the feedback of the quantum bit error rate. Two experiments with and without compensation are performed in lab and the records of sifted key rate and quantum bit error rate prove that the scheme is effective.

A novel low-power and cost-effective thresholder realized by a distributed-feedback (DFB) semiconductor laser under optical pulses injection is proposed and experimentally demonstrated.

Earth’s inner core is known to consist of crystalline iron alloyed with a small amount of nickel and lighter elements, but the shear wave (S wave) travels through the inner core at about half the speed expected for most iron-rich alloys under relevant pressures. The anomalously low S-wave velocity (v_S) has been attributed to the presence of liquid, hence questioning the solidity of the inner core. Here we report new experimental data up to core pressures on iron carbide Fe_7C_3, a candidate component of the inner core, showing that its sound velocities dropped significantly near the end of a pressure-induced spin-pairing transition, which took place gradually between 10 GPa and 53 GPa. Following the transition, the sound velocities increased with density at an exceptionally low rate. Extrapolating the data to the inner core pressure and accounting for the temperature effect, we found that low-spin Fe_7C_3 can reproduce the observed v_S of the inner core, thus eliminating the need to invoke partial melting or a postulated large temperature effect. The model of a carbon-rich inner core may be consistent with existing constraints on the Earth's carbon budget and would imply that as much as two thirds of the planet's carbon is hidden in its center sphere.

NPAT is an in vivo substrate of cyclin E-Cdk2 kinase and is thought to play a critical role in coordinated transcriptional activation of histone genes during the G(1)/S-phase transition and in S-phase entry in mammalian cells. Here we show that NPAT transcription is up-regulated at the G(1)/S-phase boundary in growth-stimulated cells and that the NPAT promoter responds to activation by E2F proteins. We demonstrate that endogenous E2F proteins interact with the promoter of the NPAT gene in vivo and that induced expression of E2F1 stimulates NPAT mRNA expression, supporting the idea that the expression of NPAT is regulated by E2F. Consistently, we find that the E2F sites in the NPAT promoter are required for its activation during the G(1)/S-phase transition. Moreover, we show that the expression of NPAT accelerates S-phase entry in cells released from quiescence. The inhibition of NPAT expression by small interfering RNA duplexes impedes cell cycle progression and histone gene expression in tissue culture cells. Thus, NPAT is an important E2F target that is required for cell cycle progression in mammalian cells. As NPAT is involved in the regulation of S-phase-specific histone gene transcription, our findings indicate that NPAT links E2F to the activation of S-phase-specific histone gene transcription.

OPTICA APPLICATA; 3/2014; ISSN 1429-7507

The behavior of synthetic-powdered ^(57)Fe-enriched enstatite (Mg_(0.980)Fe_(0.020(5)))(Mg_(0.760)Fe_(0.240))Si_2O_6 has been explored by X-ray diffraction (XRD) and nuclear resonant inelastic X-ray scattering (NRIXS). The Pbca-structured enstatite sample was compressed in fine pressure increments for our independent XRD measurements. One structural transition between 10.1 and 12.2 GPa has been identified from the XRD data. The XRD reflections observed for the high-pressure phase are best matched with space group P2_1/c. We combine density functional theory with Mössbauer spectroscopy and NRIXS to understand the local site symmetry of the Fe atoms in our sample. A third-order Birch-Murnaghan (BM3) equation of state fitting gives K_(T0)=103±5 GPa and K'_(T0)=13±2 for the Pbca phase. At 12 GPa, a BM3 fitting gives K_(T12)=220±10 GPa with K'_(T12)=8±4 for the P2_1/c phase. NRIXS measurements were performed with in situ XRD up to 17 GPa. The partial phonon density of states (DOS) was derived from the raw NRIXS data, and from the low-energy region of the DOS, the Debye sound velocity was determined. We use the equation of state determined from XRD and Debye sound velocity to compute the isotropic compressional (V_P) and shear (V_S) wave velocities of enstatite at different pressures. Our results help constrain the high-pressure properties of Pbca-structured enstatite in the Earth's upper mantle. We find that candidate upper mantle phase assemblages containing Pbca-structured enstatite are associated with shear velocity gradients that are higher than the average Earth model PREM but lower than regional studies down to about 250 km depth.

To evaluate the requirement for protein kinase Cβ (PKCβ) in the development of lupus in mice, and to explore the potential of targeting PKCβ as a therapeutic strategy in lupus.Congenic mice bearing the disease loci Sle1 or Sle1 and Sle3, which represent different stages of severity in the development of lupus, were crossed with PKCβ-deficient mice. The effect of PKCβ deficiency in lupus development was analyzed. In addition, the effects of the PKCβ-specific inhibitor enzastaurin on the survival of B cells from mice with lupus and human 9G4-positive B cells as well as the in vivo effect of enzastaurin treatment on the development of lupus in Sle mice were investigated.In Sle mice, PKCβ deficiency abrogated lupus-associated phenotypes, including high autoantibody levels, proteinuria, and histologic features of lupus nephritis. Significant decreases in spleen size and in the peritoneal B-1 cell population, reduced numbers of activated CD4 T cells, and normalized CD4:CD8 ratios were observed. PKCβ deficiency induced an anergic B cell phenotype and preferentially inhibited autoreactive plasma cells and autoantibodies in mice with lupus. Inhibition of PKCβ enhanced apoptosis of both B cells from Sle mice and human autoreactive B cells (9G4 positive). Treatment of Sle mice with the PKCβ-specific inhibitor enzastaurin prevented the development of lupus.This study identifies PKCβ as a central mediator of lupus pathogenesis, suggesting that PKCβ represents a promising therapeutic target for the treatment of systemic lupus erythematosus. Moreover, the results indicate the feasibility of using a PKCβ inhibitor for the treatment of lupus.

The [FeFe] hydrogenase from Clostridium pasteurianum (CpI) harbors four Fe-S clusters that facilitate the transfer of an electron to the H-cluster, a ligand-coordinated six-iron prosthetic group that catalyzes the redox interconversion of protons and H(2). Here, we have used (57)Fe nuclear resonance vibrational spectroscopy (NRVS) to study the iron centers in CpI, and we compare our data to that for a [4Fe-4S] ferredoxin as well as a model complex resembling the [2Fe](H) catalytic domain of the H-cluster. To enrich the hydrogenase with (57)Fe nuclei, we used cell-free methods to post-translationally mature the enzyme. Specifically, inactive CpI apoprotein with (56)Fe-labeled Fe-S clusters was activated in vitro using (57)Fe-enriched maturation proteins. This approach enabled us to selectively label the [2Fe](H) subcluster with (57)Fe, which NRVS confirms by detecting (57)Fe-CO and (57)Fe-CN normal modes from the H-cluster nonprotein ligands. The NRVS and iron quantification results also suggest that the hydrogenase contains a second (57)Fe-S cluster. Electron paramagnetic resonance (EPR) spectroscopy indicates that this (57)Fe-enriched metal center is not the [4Fe-4S](H) subcluster of the H-cluster. This finding demonstrates that the CpI hydrogenase retained an (56)Fe-enriched [4Fe-4S](H) cluster during in vitro maturation, providing unambiguous evidence of stepwise assembly of the H-cluster. In addition, this work represents the first NRVS characterization of [FeFe] hydrogenases.

We have determined the elastic and vibrational properties of periclase-structured (Mg_(0.65)Fe_(0.35))O (“FP35”), a composition representative of deep mantle “pyrolite” or chondrite-pyroxenite models, from nuclear resonant inelastic x-ray scattering (NRIXS) and x-ray diffraction (XRD) measurements in diamond-anvil cells at 300 K. Combining with in situ XRD measurements, the Debye sound velocity of FP35 was determined from the low-energy region of the partial phonon density of states (DOS) obtained from NRIXS measurements in the pressure range of 70 to 140 GPa. In order to obtain an accurate description of the equation of state (EOS) for FP35, separate XRD measurements were performed up to 126 GPa at 300 K. A new spin crossover EOS was introduced and applied to the full P-V data set, resulting in a zero-pressure volume V_0 = 77.24 ± 0.17 Å^3, bulk modulus K_0 = 159 ± 8 GPa and its pressure-derivative K′_0 = 4.12 ± 0.42 for high-spin FP35 and K_(0,LS) = 72.9 ± 1.3 Å^3, K_(0,LS) = 182 ± 17 GPa with K′_(0,LS) fixed to 4 for low-spin FP35. The high-spin to low-spin transition occurs at 64 ± 3 GPa. Using the spin crossover EOS and Debye sound velocity, we derived the shear (V_S) and compressional (V_P) velocities for FP35. Comparing our data with previous results on (Mg,Fe)O at similar pressures, we find that the addition of iron decreases both V_P and V_S, while elevating their ratio (V_P/V_S). Small amounts (

Summary According to the data such as outcrops, cores, well logging with imaging, and thin sections, the natural fractures are developed in ultra-low permeability reservoirs. The fracture types are with tectonic shear fractures as the dominated which appear in groups and en echelon arrangement. Natural fractures are most developed in sandstone and siltstone, but rarely developed in mudstone. The tectonic fractures show themself in four groups of the NE, NW, near EW and near SN orientations. Influenced by the heterogeneity of rock mechanics and the current stress field, fractures in NE-orientation are with wide opening and high permeability. Therefore the NE-orientation is the main flow direction of fluid in this area. On the basis of the traditional fracture description methods, a geological model of reservoirs considering the natural fractures is established with the help of modern fine reservoir description and fracture modeling techniques. The planar distribution laws of effective natural fractures that tally with production performance are determined by application of a numerical reservoir simulation inversion technique. A model considering natural fractures and non-Darcy flow is creatively established on the above mentioned basis. Quantitative evaluation of natural fracture and matrix's contribution to the individual well production rate has been conducted by using this model and the numerical reservoir simulation technique. The contribution rate of natural fractures obtained from the two methods to the average individual well production is 30%–40%. Research results show that the understanding of influences of natural fractures on development results of the ultra-low permeability reservoirs is deepened. Quantitive description of effective natural fractures and their assessment method of the contribution rate to the productivity have been preliminarily formed at the same time, which can be used for reference in the development of the same kind of reservoirs.

Double-crystal x-ray diffraction has been used to measure the rocking curve of Ta/Al multilayers. The diffraction profiles of the multilayers are different. Besides the normal profile, two kinds of distorted profiles have been found. The simulations show that the deformed profiles of the peaks are caused by the imperfect periodicity (e.g. systematic period deviation and coexistence of two slightly different periods) in the multilayers.

The dislocations in lithium tetraborate crystal have been investigated by means of synchrotron radiation white beam topography in BSRL (Beijing Synchrotron Radiation Laboratory). The Burgers' vectors of these dislocations are determined by their vanishing conditions. Both screw and edge dislocations exist in the specimen.

In eukaryotic cells, histone gene expression is one of the major events that mark entry into S phase. While this process is tightly linked to cell cycle position, how it is regulated by the cell cycle machinery is not known. Here we show that NPAT, a substrate of the cyclin E-Cdk2 complex, is associated with human replication-dependent histone gene clusters on both chromosomes 1 and 6 in S phase. We demonstrate that NPAT activates histone gene transcription and that this activation is dependent on the promoter elements (SSCSs) previously proposed to mediate cell cycle-dependent transcription. Cyclin E is also associated with the histone gene loci, and cyclin E-Cdk2 stimulates the NPAT-mediated activation of histone gene transcription. Thus, our results both show that NPAT is involved in a key S phase event and provide a link between the cell cycle machinery and activation of histone gene transcription.

The formula of harmonic diffraction from a perfect crystal is worked out based on the concept of dynamical diffraction and the spectrum of synchrotron radiation. As an applica-tion, the harmonic diffraction from several commonly used planes of Si crystal is calculated, which reveals that there are more harmonics in the chosen (333) diffraction than the other planes. The data are merely true for the Topography Station at Beijing Synchrotron Radia-tion Lab. (BSRL), Beijing Electron-Positron Collider (BEPC).