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Invariant sets and solutions to the generalized thin film equation

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Science china mathematics 2007年第6期50卷 875-886页

作者： Chang-zheng QU & Chun-rong ZHU Center for Nonlinear Studies, northwest university, xi’an 710069,{2. Department of mathematics, northwest university, xi’an 710069,{2. Department of mathematics, Anhui Normal university, Wuhu 2.1000,{2. 1. Center for Nonlinear Studies Northwest University Xi’an 710069 China 2. Department of mathematics Northwest University Xi’an 710069 China 3. Department of mathematics Anhui Normal University Wuhu 241000 China

The invariant sets and the solutions of the 1+2.dimensional generalized thin film equation are discussed. It is shown that there exists a class of solutions to the equations, which are invariant with respect to the set $$E_0 = \{ u:u_x = v_x F(u),u_y = v_y F(u)\} ,$$ where v is a smooth function of variables x, y and F is a smooth function of u. This extends the results of Galaktionov (2.01) and for the 1+1-dimensional nonlinear evolution equations.

关键词： thin film equation invariant set invariant solution rotation group scaling group 35K55 35K40 82.2.

On the Mean Value Formula of Dedekind Sums

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Acta Mathematica Sinica,English Series 1999年第2期15卷 245-254页

作者： xiali He Wenpeng Zhang, Department of mathematics, northwest university,{2., P. R. china Department of mathematics Northwest University Xi’an P. R. China

The main purpose of this paper is to use the mean value theorem of the Dirichlet L-function to study the distribution property of Dedekind sums, and to give a sharper mean value formula.

关键词： Dedekind sums Distribution of the mean value Asymptotic formula

PRELIMINARY GROUP CLASSIFICATION OF EQUATION v_t=f(x, v_x)v_(xx)+g(x, v_x)

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Acta Mathematica Scientia 1997年第3期17卷 255-261页

作者：屈长征 Department of mathematics Northwest University Xi'an 710069 China

Using the method of preliminary group classification introduced by Ibragimov et al[***.32.2.88(1991)], we give a classification of equations vt= f(x, vx)vxx+g(x, vx) which admitting an extension by one of the principal Lie algebra of the equation. The result of this paper is a table of nonequivalent equations possessing an additional symmetry.

关键词： SYMMETRY CLASSES COEFFICIENT

Thermal decomposition of Pr[（C5H8NS2.3(C12.8N2.]

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Science china Chemistry 2005年第S1期48卷 83-87页

作者： GUO Pengjiang,JIAO Baojuan,CHEN Sanping,HU Rongzu,GAO Shengli & SHI Qizhen Department of Chemistry,northwest university Shaanxi Key Laboratory of Physico-lnorganic Chemistry,xi'an {2.,china Department of mathematics,northwest university,xi'an {2.,china xi'an Modern Chemistry Research Institute,xi'an 710065,china NW Univ xian Dept Chem Shaanxi Key Lab Physicoinorgan Chem Xian 710069 Peoples R China NW Univ xian Dept Math Xian 710069 Peoples R China xian Modern Chem Res Inst Xian 710065 Peoples R China

The thermal behavior of the complex Pr[(C5H8NS2.3(C12.8N2.] in a dry nitrogen flow was examined by TG-DTG analysis. The TG-DTG investigations indicated that Pr[(C5H8NS2.3-(C12.8N2.] was decomposed into Pr2.3 and deposited carbon in one step where Pr2.3 predominated in the final products. The results of non-isothermal kinetic calculations showed that the decomposition stage was the random nucleation and subsequent growth mechanism (n = 2.3), the corresponding apparent activation energy ?was 115.89 kJ·mol-1 and the pre-expo-nential constant ln[A/s] was 7.8697. The empirical kinetics model equation was proposed as/(α) =3/2.1-α)[-ln(1-α)]1/*** X-ray powder diffraction patterns of the thermal decomposition products at 800℃under N2.atmosphere show that the product can be indexed to the cubic Pr2.3 phase. The transmission electron microscopy (TEM) of the final product reveals the particle appearance of a diameter within 40 nm. The experimental results show that the praseodymium sulfide nanocrystal can be prepared from thermal decomposition of Pr[(C5H8NS2.3(C12.8N2.].

关键词： Pr[(C5H8NS2.3(C12.8N2.] thermal analysis kinetics noncrystal characteristics

Vermiform trace fossils from the Precambrian Ruyang Group, western Henan

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Chinese Science Bulletin 1997年第3期42卷 251-254页

作者： HU Jianmin, MENG Qingren and LI Wenhou1 xi’ an College of Geology, xi’an 710054, china 2. Institute of Geophysics, Chinese Academy of Sciences, Beijing 100101, china 3 Department of Geology,{2., xi’an 710069, china xi’an College of Geology Xi’an China Institute of Geophysics Chinese Academy of Sciences Beijing China Department of Geology Northwest University Xi’an China

THE origin and evolution of Precambrian lives has been a long-standing controversial problem. It is now generally accepted by most paleontologists that the origin of metazoa can be traced back to more than 1000 Ma, because the Ediacara and latest pre-Ediacara fauna, such as the Huainan fauna, are featured by their diversification of forms, complicated structures

关键词： Precambrian trace fossil Ruyang Group.

Optimal regulation of flexible loads in rural residential buildings considering mobile batteries:A case study in Shaanxi Province

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Building Simulation 2024年第7期17卷 1065-1083页

作者： xi Luo WenceShi School of Building Services Science and Engineering Xian University of Architecture and Technology(XAUAT)Xi'an 710055China State Key Laboratory of Green Building Xi'an 710055China

While the grid-connected capacity of rural household photovoltaics is increasing rapidly,achieving dynamic supply-demand matching despite fluctuations in solar energy is *** the rapid development of rural electrification,battery-powered technologies,such as electric vehicles and electric agricultural machinery,are becoming increasingly popular in rural *** this context,utilizing idle mobile batteries to assist in energy storage for rural residential buildings offers a new way to solve the problem of dynamic supply-demand *** this study,a field survey was conducted on several typical fruit-growing villages in the Central Shaanxi Plain in Shaanxi Province of *** rural households were selected to calculate the electricity loads of the residential buildings,with due consideration to the intervention of mobile *** the premise of installing 3 kW household photovoltaic systems in rural households,an economical efficiency-oriented model was built for the optimal regulation of flexible *** results were compared in the context of two patterns of electricity consumption,i.e.,unidirectional charging of mobile batteries from buildings and bidirectional charging and discharging between mobile batteries and *** bidirectional pattern significantly increased the photovoltaic consumption of typical rural households on various typical ***,during both scenarios of not implementing time-of-use and implementing time-of-use,the typical day of the winter slack farming season exhibited the best photovoltaic consumption effect among all types of typical ***,the bidirectional pattern also result in a significant increase in the annual electricity sales revenues for typical rural households.

关键词： demand-side response flexible load mobile battery household photovoltaics

Northernmost paleo-tethyan oceanic basin in Tibet:Geo-chronological evidence from ^(40)Ar/^(39)Ar age dating of Dur'ngoi ophiolite

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Chinese Science Bulletin 2001年第14期46卷 1203-1205页

作者： CHEN Liang, SUN Yong, PEI xianzhi, GAO Ming, FENG Tao, ZHANG Zhongqing & CHEN Wen1. Laboratory of Continental Dynamics, northwest university, xi’an 710069,{2. 2. Department of Geology, northwest university, xi’an, 710069,{2. 3. Institute of Geology, Chinese Academy of Geological Sciences, Beijing, 100037,{2. Laboratory of Continental Dynamics Northwest University Xi’an China Department of Geology Northwest University Xi’an China Institute of Geology Chinese Academy of Geological Sciences Beijing China

Whole rock 40Ar/39Ar age dating has been conducted on a basalt sample from Dur’ngoi ophiolite, Qinghai Province, which was reported to be the northernmost pa-leo-tethyan oceanic basin in Tibet. A high temperature pla-teau age (345.3±7.9 Ma) with an isochorn age (336.6±7.1 Ma) has been obtained, representing the eruption time of oceanic crust Considering related geological settings, the new age provides constraints on the northernmost pa-leo-tethyan suture zone in Tibet and the tectonic evolution of Paleo-tethys in Northeast Tibet and adjacent areas.

关键词： Dur’ngoi ophlolite 40Ar -39Ar age Paleo-tethys.

Energy consumption simulations of rural residential buildings considering differences in energy use behavior among family members

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Building Simulation 2024年第8期17卷 1335-1358页

作者： xi Luo Lina Du School of Building Services Science and Engineering Xi'an University of Architecture and Technology(XAUAT)Xi'an 710055China State Key Laboratory of Green Building Xi'an 710055China

The“average occupant”methodology is widely used in energy consumption simulations of residential buildings;however,it fails to consider the differences in energy use behavior among family *** on a field survey on the Central Shaanxi Plain,to identify the energy use behavior patterns of typical families,a stochastic energy use behavior model considering differences in energy use behavior among family members was proposed,to improve the accuracy of energy consumption simulations of residential *** results indicated that the surveyed rural families could be classified into the following four types depending on specific energy use behavior patterns:families of one elderly couple,families of one middle-aged couple,families of one elderly couple and one child,and families of one couple and one ***,on typical summer days,the results of daily building energy consumption simulation obtained by the“average occupant”methodology were 2..39%and 2.%lower than the simulation results obtained by the model proposed in this study for families of one elderly couple and families of one middle-aged couple,and 13.05%and 2..05%higher for families of one elderly couple and one child,and families of one couple and one *** typical winter days,for the four types of families,the results of daily building energy consumption simulation obtained by the“average occupant”methodology were 2..69%,10.84%,1.2.%,and 8.39%lower than the simulation results obtained by the model proposed in this study,respectively.

关键词： typical energy use behavior pattern differences in occupant behavior building energy consumption simulation stochastic energy use behavior simulation

Congruences on ideal nil-extension of completely regular semigroups

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Chinese Science Bulletin 1998年第5期43卷 379-381页

作者： REN Xueming 1, 2.GUO Yuqi 2.and CEN Jiaping (Shum Kar-ping) 31. Department of mathematics, xi’an university of Architecture & Technology, xi’an 710055,{2. 2. Department of mathematics, Yunnan university, Kunming 650091,{2. 3. Department of Department of mathematics Xi’an University of Architecture & Technology Xi’an China Department of mathematics Yunnan University Kunming China Department of mathematics Chinese University of Hong Kong Hong Kong

Let S be an ideal nil-extension of a completely regular semigroup K by a nil semigroup Q with zero. A concept of admissible congruence pairs (δ,ω) of S is introduced, where δ and ω are a congruence on Q and a congruence on K respectively. It is proved that every congruence on S can be uniquely respresented by an admissible congruence pair (δ,ω) of S. Suppose that ρ K denotes the Rees congruence induced by the ideal K of S. Then it is shown that for any congruence σ on S,a mapping Γ:σ|→(σ Q,σ K) is an order-preserving bijection from the set of all congruences on S onto the set of all admissible congruence pairs of S,where σ K is the restriction of σ to K and σ Q=(σ∨ρ K)/ρ K. Moreover,the lattice of congruences of S is also discussed. As a special case,every congruence on completely Archimedean semigroups S is described by an admissible quarterple of S. The following question is asked: Is the lattice of congruences of the completely Archimedean semigroup a semimodular lattice?

关键词： completely regular semigroups ideal nil-extension congruences.