Physical and dynamical parameters of the multiple system HD 222326

We present the results of our study of the physical and dynamical parameters of the multiple system HD 222326. A new method for determining the individual radial velocities of components in wide binary and multiple systems in the case of small radial-velocity differences (δV _r ≤ the FWHMfor the line profiles) is suggested and tested for both model systems and the binary HD 10009. This testing yielded the component radial velocities V _{r 1,2} for HD 10009, enabling us to derive the center-of mass velocity, V _γ, for the first time. We determined the radial velocities of the components of HD 222326 from high-resolution spectra, and refined the orbital parameters of the subsystems using speckle-interferometric observations. A combined spectroscopic and speckle interferometric analysis enabled us to find the positions of the components in the spectral type—luminosity diagram and to estimate their masses. It is likely that the components are all in various evolutionary stages after leaving the main sequence. We analyzed the dynamical evolution of the system using numerical modeling in the gravitational three-body problem and the known stability criteria for triple systems. The system is probably stable on time scales of at least 10⁶ years. The presence of a fourth component in the system is also suggested.     

Bonding and dynamical phenomena in MgO: A high temperature 17O and 25Mg NMR study

We have measured the isotropic chemical shifts (δ_iso) and the spin-lattice relaxation times (T₁) for ¹⁷O and ²⁵Mg in MgO from room temperature up to 1300° C. The ¹⁷O chemical shifts increase linearly from 47 ppm at room temperature to 57 ppm at 1300° C, and over the same temperature range the ²⁵Mg chemical shift increases linearly from 25 to 27 ppm. These changes are not the result of changes in the bulk magnetic susceptibility of the samples, but may be due to increased orbital overlap which is the result of the increase in thermal vibration of the ions with temperature. In the case of ²⁵Mg, the shift to lower shielding with increasing temperature is opposite to that expected from simple bond length versus chemical shift trends established for the oxides at room temperature. If this is a general phenomenon, high-temperature NMR data may be biased to lower shielding. Spin-lattice relaxation times (T₁) were measured in order to study the energetics of defect motion. T₁'s for ¹⁷O and ²⁵Mg exhibit similar behavior over the range of temperatures studied. Up to 800° C, T₁'s decrease gradually, but above 800° C, T₁'s drop rapidly, with slopes corresponding to apparent activation energies of 192±9 kJ/mol (2.0±0.1 eV) for ¹⁷O and 151±6 kJ/mol (1.56±0.06 eV) for ²⁵Mg. While direct comparison of these activation energies to those derived from diffusion or conductivity measurements is complicated, the similar behavior for both nuclei suggests their relaxation phenomena are related.     

A dynamical study of 12 wide visual binaries

We have carried out the first dynamical studies of the relative motions of the components of 12 wide binaries: ADS 497, ADS 2427 (GL 130.1), ADS 3593, ADS 5436, ADS 6646, ADS 6783, ADS 9559 (δ Boo), ADS 10329, ADS 10759 (ψ Dra), ADS 14878, ADS 15229, and ADS 16558. The analysis is based on series of photographic observations made with the 26-inch refractor of Pulkovo Observatory, supplemented by data from the WDS Catalog, radial velocities and HIPPARCOS parallaxes. We used the parameters of the apparent motions, which can yield the orbit and mass of a binary from observations over a short arc of the orbit of the order of 5°–10°. The orbits and masses for six stars with orbital periods from 500 to 20 000 years have been reliably determined. For five stars with periods from 2000 to 100 000 years, we obtained probable orbits and mass estimates. For ADS 497 and ADS 10329, the mass excesses in their systems are 1 and 3 M _⊙, respectively, relative to the masses expected from the mass-luminosity dependence. In three cases, for ADS 3593, ADS 14878, and ADS 16558, the obtained estimates of the total mass of the components are 46, 25, and 7300 M _⊙, respectively, if the parallaxes are correct. A perturbation with amplitude 0.3″ and period 40 yrs has been detected in the orbital motion of the system ADS 10759, possibly indicating the presence of an invisible satellite with a mass of the order of 0.4 M _⊙. The orientations of the orbits in the Galactic reference frame have been determined for all 12 binaries. The planes of most of the obtained orbits are steeply inclined to the plane of the Galaxy, as was noted in previous studies.     

A dynamical study of the wide hierarchic triple star ADS 10288

We have performed the first dynamical study of the relative motions of the components of the wide hierarchic triple star system ADS 10288 (GL 649.1 = WDS 16579+4722), based on a 15-year series of photographic observations with the 26″ Pulkovo refractor, supplemented with data from the WDS catalog, HIPPARCOS parallaxes, and radial velocities of the components. The radial velocities were measured in Simeiz using the ILS stellar radial-velocity correlation spectrometer designed by A.A. Tokovinin. We applied the parameters of the apparent motion technique, which makes it possible to derive a binary’s orbit and mass from observations of a short arc, about 5°–10° in length. We derived preliminary orbits for the pairs AB and (AB)-C, whose orbital periods are 340 and 64 000 years, respectively. Mass estimates derived from the mass-luminosity relation are consistent with our dynamical estimates. We determined the orientation of the orbits in Galactic coordinates. The orbital planes are not coplanar, and are steeply inclined to the Galactic plane, as was the case in our earlier studies for most wide visual pairs we have studied.     

Physical parameters and dynamical properties of the multiple star o and

An analysis of the physical characteristics, orbital parameters, and dynamical stability of the multiple Be star HD 217675 (o And) is presented. Observations on the 6-m SAO and 1.5-m RTT telescopes are used to refine the orbital parameters of the subsystems. The spectral types, absolute magnitudes, and masses of the components are estimated. The total mass of the system is 18 ± 2 M _db. It is shown that the configuration of the system is 2 + 2, where one of the subsystems is a spectral binary with a period of 33 d and the outer pair has a period of 117 yr. The parameters of the second inner subsystem are uncertain, making it difficult to draw firm conclusions about the stability of this multiple star.     

Analysis of the dynamical instability of several multiple stars with weak hierarchy

The dynamical stability of 16 multiple stars is analyzed using Monte Carlo simulations with allowance for the errors in the observational data. The analysis was carried out by varying the uncertainties in the initial observational data. Six different stability criteria were considered, and the dynamical evolution was studied using numerical simulations. Eleven of the systems are probably stable, whereas five systems (HD 40887, HD 136176, HD 150680, HD 217675, and HD 222326) are probably unstable (the probability that they are unstable is 0.94 or more accordingt o the results of forward and backward simulations over intervals of 10⁶ yr). The results of the simulations were most consistent with the criteria of Mardling-Aarseth (the correlation coefficient between the probabilities of disruption inferred from the stability criterion and numerical integration was r = 0.998), Valtonen-Karttunen (r = 0.998), and Eggleton-Kiseleva (r = 0.997). In about 92–93% of all cases, these criteria yield results that are consistent with the numerical simulations. These criteria also yield high disruption probabilities for the unstable systems. Scenarios for the formation of such systems are discussed: temporary capture of a field star by a close binary, perturbation of a stable multiple system by a massive field object, and disruption of small stellar groups or clusters. The probabilities that these scenarios are realized are analyzed.     

A dynamical model of the Galaxy

A series of dynamical models of the Galaxy is constructed assuming that the entire disk is near the gravitational-stability limit. This imposes constraints on the dynamical and kinematic parameters of the main subsystems (the disk, bulge, and halo). The disk surface density in the solar neighborhood should not exceed 58 M_⊙/pc². Further, we find that the observed local decrease in the rotational velocity at 6 kpc ? r ? 10 kpc is not associated with details of the radial distribution of matter in the Galaxy and instead results from dynamical processes or some other factors responsible for noncircular motions. It follows from the presence of a long-lived bar and the observed distribution of the stellar-velocity dispersion that the central maximum in the rotation curve at radius r ? 300 pc cannot be associated with a very concentrated bulge core. The best agreement between the observational data and the parameters of the dynamical models is achieved for a radial disk scale length of L ? 3 kpc. The relative contribution of the disk to the circular rotational velocity at r = 2.2L is 73%.     

Parameters of the dust envelope of the symbiotic star CH Cygni

The brightness and color variations of the symbiotic star CH Cygni are studied, and its stationary, spherically symmetric, extended dust envelope is modeled based on long-term UBVRJHKLM photometry, the mid-IR spectral energy distribution (7–23 µm), and far-IR fluxes measured by IRAS and ISO. The existence of a hot dust envelope, detected earlier in the near IR, is confirmed; the optical depth of the envelope has probably increased with time. Model fits to the IRAS and ISO data indicate that the V-band optical depth increased from 0.22 to 0.41 due to dust density enhancement during the 14 years between the observations by the two spacecraft. The mass-loss rate, gas-expansion velocity at the outer boundary of the envelope, and upper limit of the mass of the central source of emission are estimated assuming that the stellar wind of the system is driven by the pressure of the red giant's radiation on the dust, with subsequent momentum transfer to the gaseous medium.     

A dynamical system for the parker dynamo in the case of quadrupole symmetry of the magnetic field

Adynamical systemin the case of quadrupolar symmetry of the toroidal field is constructed. The system obtained reproduces the regimes of oscillations, vacillations, dynamo bursts, and a configuration with monotonically growing magnetic fields reaching stationary regimes. The ranges of dynamo numbers corresponding to these regimes are found. Butterfly diagrams for the steady-oscillation regime are constructed for both the poloidal and toroidal components of the magnetic field.     

Photometric parameters of the dwarf nova SS Cygni in the quiescent state

The mean 1983–1996 UBV light curves of the dwarf nova SS Cyg are used to derive the binary parameters in the quiescent state. Solutions are obtained for a classical hot-spot model and a model with an energy source lying outside the accretion disk. Photometric and spectroscopic data are combined to infer the masses and radii of the binary components. The white dwarf in SS Cyg is one and a half times as massive as the red dwarf, q=M _wd /M _rd ～1.45, M _rd ～0.46M _⊙ and M _wd ～0.66M _⊙. The orbital inclination of the system is i?51°–54°. The contribution of the accretion disk to the total flux in the quiescent state is estimated to be ～47–49% and ～54% in the VU and B filters, respectively. The hot spot contributes less than ～3% to the total optical flux. In the “non-classical” hot-spot model, the disk and bulge contributions are 27 and 2–8%, respectively, depending on the orbital phase. The shape of the mean light curves of SS Cyg suggests asymmetric heating of the red-dwarf surface in the quiescent state by high-temperature radiation generated in the hot-spot region.     

Variations of the parameters of the dust envelope of the symbiotic star CH Cygni

The results of JHKLM photometry of the symbiotic star CH Cyg are presented. These demonstrate that, in Autumn 2006, the state of maximum near-IR brightness observed in 2003–2006 was replaced by a sharp brightness decline in all wavebands. One possible explanation is a sharp increase in the density of circumstellar dust envelope. The JHKLM photometry data together with ISO far-IR flux measurements are used to calculate spherically symmetric dust-envelope models for the maximum and minimum brightness states. The optical depth, expansion rate, and mass-loss rate of the envelope are calculated for both states, as well as an upper limit for the mass of the central source. Comparison with earlier models suggests that the rate of growth of the envelope optical depth and the mass-loss rate by the star are accelerating with time.     

滨海岩溶地区海咸水入侵动力学系统研究

我国滨海岩溶地区岩溶系统的形成具有其独特的动力学过程。其中,既有自然环境条件下形成的岩溶特征,又有人类活动的地质效应——海咸水入侵的影响和改造。目前,海咸水入侵对滨海岩溶系统的影响和改造正在加剧,并将逐渐成为主导因素。防治滨海岩溶区海咸水入侵的根本,就是要查明咸-淡水过渡带中碳酸盐岩溶解、沉淀的动力机制。其中,混合溶蚀作用是关键。开展咸-淡水过渡带碳酸盐岩溶解、沉淀动力学的野外现场定位观测和室内动态模拟实验研究,并在查明咸-淡水过渡带碳酸盐岩溶解、沉淀动力机理的基础上,建立滨海岩溶地区碳酸盐岩溶解、沉淀系统动力学模型是十分必要和迫切的。研究各种因素综合影响下,滨海碳酸盐岩的混合溶蚀作用,将有利于查明滨海岩溶形成机理,进而为解决滨海岩溶地区海咸水入侵问题开辟一条新的途径。     

Dissipation of the hot dust envelope of CH Cygni (1996–2003)

Our analysis of JHKLM photometric data obtained in 1978–2003 for the CH Cyg system shows that the “local” dust envelope that formed in the system in 1986 and reached its highest column density in 1996 had largely dispersed by mid-2001, so that the observed brightness of the system’s red giant has returned to its pre-1985 level. The giant’s spectral type varied in the range M6.5–M7.5 in 2001–2003. The optical depth of the dust envelope at 1.25 µm was τ(J)≈0.83 near JD 2450090. The increase in the dust envelope’s optical depth was approximately a factor of 2.3 slower than the decrease. The envelope of CH Cyg can be pictured as a “stationary” dust cloud with an optical depth at λ=1.25 µm of ～0.4 and a dust-grain temperature of ～750–800 K. There was probably an injection of matter into this cloud toward the end of 1985, initiating the condensation of dust grains. The optical depth began to increase and, by 1991, the dust envelope was transformed from a cloud into a local, almost spherically-symmetric envelope with a grain temperature of 750–800 K. Its optical depth reached its maximum in 1996, after which the local envelope began to disperse, becoming a cloud again by 2001. The detected 4000-day variability of the JHK brightness of CH Cyg is in good agreement with a model with an eclipsing binary consisting of two cool giants with effective temperatures differing by approximately 100 K, a luminosity ratio of L(M7)/L(M6)～6.8, and a radius ratio of R(M7)/R(M6)～3.6. The orbital ephemeris is given by JD (Min I)=2444180+4000E.     

区域地质调查标准体系研究

地质填图是一项旨在查明国家基本地质情况的超前性、公益性、战略性、多用途的基础性地质工作,为资源勘查、环境保护、工程建设、城市规划、国土开发利用、地球科学发展等提供重要支撑。完善的技术标准是区域地质调查的重要技术保障。中国的地质填图技术标准经历半个多世纪的发展,形成了基本完善的技术标准体系。随着经济与科技的发展,当前地质填图技术标准未能与实际工作同步跟进,出现技术标准难以满足当前地质填图工作需求、地质填图标准不统一、标准体系不完善等问题。在新形势下,根据中国半个多世纪以来地质填图技术标准体系的发展经验,学习国外发达国家先进的地质填图理念、方法和标准,结合中国地质填图工作实际状况与需求,在分析梳理地质填图标准的基础上,提出地质填图标准体系框架和推进地质填图标准更新与完善的建议,以满足现代地质填图需求。     

复合型含油气系统的特征与描述 : 以塔中含油气系统为例

通过对塔中含油气系统的研究，发现它难以用传统的含油气系统方法来描述。它主要有二个油源区三套生油岩，发育有三套储层；不同油源在不同时期生成的油气在储层内共生、甚至相互混合，使油气成因复杂。据此提出了它是一个复合型含油气系统。在此基础上，进一步指出复合型含油气系统的特点是多油源、多期成烃、油气成因复杂，出现在迭合型盆地。并针对这些特点，初步提出了工作思路及描述方法。     

A multiple scale modeling system for coastal hurricane wind damage mitigation

Hurricane wind damage constitutes the largest percentage of catastrophic insured losses in the US. Yet the complicated wind structures and their changes are not fully understood and, thus, have not been considered in current risk catastrophic models. To obtain realistic landfall hurricane surface winds, a large eddy simulation (LES) framework in a weather forecasting mode has been developed from a multiple nested Weather Research & Forecasting (WRF) model to explicitly simulate a spectrum of scales from large-scale background flow, hurricane vortex, mesoscale organizations, down to fine-scale turbulent eddies in a unified system. The unique WRF-LES enables the high resolution data to be generated in a realistic environment as a hurricane evolves. In this paper, a simulation of the landfalling Hurricane Katrina is presented to demonstrate various features of the WRF-LES. It shows that the localized damaging winds are caused by the large eddy circulations generated in the hurricane boundary layer. With a sufficient computational power, WRF-LES has the potential to be developed into the next generation operational public wind-field model for hurricane wind damage mitigation.     

地学G4I系统的开发研究

G4I系统基于数据集成、发掘与信息融合这一构想,设计开发了一种以地质学、地理学、地球化学、地球物理学等地学数据信息集成分析为内核,提供矿产资源预测服务为目标的计算机系统,是服务于地壳下位空间信息机理与模型分析体系的数字化地学信息平台。本文介绍了地学G4I系统的设计原理与过程,以及应用到“河北地勘局多源地学信息系统”中。     

航空重力仪减振系统振动研究

航空重力减振系统是有效减弱机载环境下高频振动的主要途径,从而提高航空重力的测量精度。因此,设计减振系统的首要问题是设定其合理的刚度、阻尼和质量等重要的特性参数。笔者通过建立航空重力仪两种减振系统类型运动微分方程,经过理论和实例探讨了减振系统模型,旨在深入了解航空重力减振系统的减振规律,为其特性参数设计提供理论依据。     

金川铜镍矿床多元地学信息找矿研究

金川铜镍矿床是世界级典型的超大型硫化铜-镍矿床之一.根据在已知剖面上开展的多元地学信息综合找矿可行性试验结果,结合该矿床的地质特征,确立了地质、地球化学、地球物理找矿标志,并建立了金川铜镍矿区深边部地-物-化综合找矿模式.依据上述找矿模式,在金川Ⅱ矿区深边部开展找矿预测工作,发现了5个具有找矿前景靶区,其中在Ⅰ类靶区②号多元信息综合异常带深部经工程验证发现了隐伏铜镍矿体.     

A case study of strut-free excavation retaining system

Acta Geotechnica - This paper presents a successful design of a strut-free excavation retaining system, namely the TPKE project. The TPKE excavation project was 13.2 m deep, covering...