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Calculation of traversal time in tunneling by double-wave theory

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Chinese Science Bulletin 1998年第9期43卷 723-727页

作者： HUANG Xiangyou department of Physics, peking university, beijing 100871, {3. department of Physis Peking University Beijing China

Becausethe information contained in a wave function is not enough to describe an individual particle, the suggestion to define the state of a particle by two-wave functions is used. In the double-wave description, a general formula telling the traversal time of a particle in tunneling is obtained. When the double-wave description over an initial parameter is averaged , it reduces to the usual description. Two new relations between the transmission and the reflected coefficients are founded in the new cescription.

关键词： tunneling double-wave theory ensemble.

A Potential Candidate For the Middle-Upper Cambrian Boundary Stratotype——An Introduction to the Paibi Section in Huayuan,Hunan

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Acta Geologica Sinica(English Edition) 1990年第3期64卷 309-327,344-346+348页

作者： Dong Xiping department of Geology, peking university, beijing department of Geology Peking University Beijing

The Middle-Upper Cambrian boundary is one of the current stratigraphical problems which remain openin the geological world, since there have been no universally acknowledged delimiting standard and *** on the instruction of Profs. Lu Yanhao and An Taixiang the author studied in details the Paibi Section,which is well exposed as a continuous sequence at an easily accessible locality. The Middle-Upper Cambrianboundary strata are composed of biocalcimicrosparite, indicating the sedimentary environment of anunderwater upheaval on the gentle slope along the frontal margin of the Yangtze carbonate platform. For the upper Middle and lower Upper Cambrian agnostid trilobite zones and conodont zones are erected,and a more accurate correlation between the trilobite and conodont sequences is established. Based on these,the Middle-Upper Cambrian boundary is drawn more reasonably and precisely than what was done before. Inshort, the section studied is superior to other known sections of Middle-Upper Cambrian. and it will probablybe an ideal candidate for the Middle-Upper Cambrian boundary stratotype.

关键词： In An Introduction to the Paibi Section in Huayuan,Hunan A Potential Candidate For the Middle-Upper Cambrian Boundary Stratotype

Deficit of mitochondria-derived ATP during oxidative stress impairs mouse MII oocyte spindles

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Cell Research 2006年第10期16卷 841-850页

作者： Xiao Zhang~(1,2,*) Xue Qing Wu~(1,3.*) Shuang Lu~(4,5,6) Ying Lu Guo~1 Xu Ma~(4,5,6) ~1peking university First hospital,Institute of Urology of{3.,beijing 10003.,china ~2Reproductive and Genetic Center of{3. First hospital,beijing 10003.,china ~3.10} of Obstetrics and Gynecology,Shanxi Medical university Second hospital,Taiyuan 03.000,china ~4Reproductive and Genetic Center of National Research Institute for Family Planning,beijing 10003.,china ~5department of Genetics, peking Union Medical College, beijing 10003.. china ~6 WHO Collaborative Center for Research in Human Reproduction,beijing 10003.,china peking university First hospital Institute of Urology of Peking University Beijing China Reproductive and Genetic Center of peking university First hospital Beijing China department of Obstetrics and Gynecology Shanxi Medical University Second Hospital Taiyuan China Reproductive and Genetic Center of National Research Institute for Family Planning Beijing China department of Genetics Peking Union Medical College Beijing China WHO Collaborative Center for Research in Human Reproduction Beijing China

Although the role of oxidative stress in maternal aging and infertility has been suggested,the underlying mechanismsare not fully *** present study is designed to determine the relationship between mitochondrial functionand spindle stability in metaphase Ⅱ （MⅡ） oocytes under oxidative stress.MⅡ mouse oocytes were treated with H2O2inthe presence or absence of permeability transition pores （PTPs） blockers cyclosporin A （CsA）.In addition,antioxidantN-acetylcysteine （NAC）,F0/F1synthase inhibitor oligomycin A,the mitochondria uncoupler carbonyl cyanide 4-trifluoro-methoxyphenylhydrazone （FCCP） or thapsigargin plus 2.5 mM Ca2+(Th+2.5 mM Ca2+) were used in mechanistic *** analyses ofoocyte spindles and chromosomes were performed and mitochondrial membrane potential（Δψm）,cytoplasmic tree calcium concentration ([Ca2+]c) and cytoplasmic ATP content within oocytes were also *** a time- and H2O2dose-dependent manner,disruption of meiotic spindles was found after oocytes were treated withH2O2,which was prevented by pre-treatment with *** of H2O2led to a dissipation of Δψm,an increasein [Ca2+]cand a decrease in cytoplasmic ATP *** detrimental responses of oocytes to H20,treatment could beblocked by pre-incubation with *** to H2O2,both oligomycin A and FCCP dissipated Δψm,decreased cytoplas-mic ATP contents and disassembled MⅡ oocyte spindles,while high [Ca2+]calone had no effects on spindle *** conclusion,the decrease in mitochondria-derived ATP during oxidative stress may cause a disassembly of mouse MⅡoocyte spindles,presumably due to the opening of the mitochondrial PTPs.

关键词： spindle oxidative stress mitochondria permeability transition pore ATP

Recommendation Method for Contrastive Enhancement of Neighborhood Information

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Computers, Materials & Continua 2024年第1期78卷 453-472页

作者： Hairong Wang beijing Zhou Lisi Zhang He Ma School of Computer Science and Engineering North Minzu UniversityNingxia750021China

Knowledge graph can assist in improving recommendation performance and is widely applied in various person-alized recommendation ***,existing knowledge-aware recommendation methods face challenges such as weak user-item interaction supervisory signals and noise in the knowledge *** tackle these issues,this paper proposes a neighbor information contrast-enhanced recommendation method by adding subtle noise to construct contrast views and employing contrastive learning to strengthen supervisory signals and reduce knowledge ***,first,this paper adopts heterogeneous propagation and knowledge-aware attention networks to obtain multi-order neighbor embedding of users and items,mining the high-order neighbor informa-tion of users and ***,in the neighbor information,this paper introduces weak noise following a uniform distribution to construct neighbor contrast views,effectively reducing the time overhead of view *** paper then performs contrastive learning between neighbor views to promote the uniformity of view information,adjusting the neighbor structure,and achieving the goal of reducing the knowledge noise in the knowledge ***,this paper introduces multi-task learning to mitigate the problem of weak supervisory *** validate the effectiveness of our method,experiments are conducted on theMovieLens-1M,MovieLens-20M,Book-Crossing,and Last-FM *** results showthat compared to the best baselines,our method shows significant improvements in AUC and F1.

关键词： Contrastive learning knowledge graph recommendation method

Rat adipose-derived stromal cells expressing BMP4 induce ectopic bone formation in vitro and in vivo

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Acta Pharmacologica Sinica 2006年第12期27卷 1608-1615页

作者： Lin LIN~2 Xin FU~2 Xin ZHANG~2 Lian-xu CHEN~2 Ji-ying ZHANG~2 Chang-long YU~(2,4)Kang-tao MA~3.Chun-yan ZHOU~(3.4)2 Institute of Sports Medicine,peking university third hospital,{3. 1.0083.china 3.department of Biochemistry and Molecular Biology,peking university School of Basic Medical Science,{3. 1.0083.china Institute of Sports Medicine Peking University Third Hospital Beijing China department of Biochemistry and Molecular Biology Peking University School of Basic Medical Science Beijing China

Aim:Bone morphogenetic protein 4(BMP4)is one of the main local contributingfactors in callus formation in the early phase of fracture ***-derivedstromal cells(ADSC)are multipotent *** present study was conducted toinvestigate the osteogenic potential of ADSC when exposed to adenovirus con-taining BMP4 cDNA(Ad-BMP4).Methods:ADSC were harvested from Sprague-Dawley *** exposure to Ad-BMP4,ADSC were assessed by alkaline phos-phatase activity(ALP)assay,RT-PCR and yon Kossa ***4 expressionwas assessed by RT-PCR,immunofluorescence and Western blot analysis,ADSCtransduced with Ad-BMP4 were directly injected into the hind limb muscles ofathyrnic *** Ad-EGFP(enhanced green fluorescence protein)served *** animals were examined by X-ray film and histological ***:The expression of BMP4 was confirmed at both mRNA and protein *** expression of the osteoblastic gene,ALP activity and yon Kossa stainingconfirmed that ADSC transduced with Ad-BMP4 underwent rapid and markedosteoblast differentiation,whereas ADSC transduced with Ad-EGFP and cells leftalone displayed no osteogenic differentiation.X-ray and histological examinationconfirmed new bone formation in athymic mice transplanted with ADSC trans-duced with ***:Our data demonstrated successful osteo-genic differentiation of ADSC transduced with Ad-BMP4 in vitro and in *** may be an ideal source of mesenchyme lineage stem cells for gene therapyand tissue engineering.

关键词： adipose-derived stromal cells BMP4 gene therapy bone formation

A preliminary analysis of arcuate structures-relationship of the island arc and deep-sea trench to the dip angle of Benioff zone

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Acta Oceanologica Sinica 1989年第1期8卷 125-136页

作者： Wu Lun, Liang Haihua, Ren Fuhu and Li Maosong The department of Geography, peking university, beijing, {3. The department of Geology, peking university, beijing, {3. Dept of Geography Peking Univ. Beijing China China

The origin of arcuate islands and deep-sea trenches has been studied for a long time and various interpretations have been proposed. In this paper, some analytical models are put forward from a geometrical viewpoint and then the theoretical dip angles of the underthrusting slabs of circum-Pacific island arcs are computed and compared with those of the Benioff zone. As a result, it is found that the dip angle of the underthrusting slab is one of the main factors determining the curvature of the arcuate structure. The authors consider that this result may contribute to the plate theory.

关键词： A preliminary analysis of arcuate structures-relationship of the island arc and deep-sea trench to the dip angle of Benioff zone deep

Circadian expression of clock genes and angiotensin Ⅱ type 1 receptors in suprachiasmatic nuclei of sinoaortic-denervated rats

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Acta Pharmacologica Sinica 2007年第4期28卷 484-492页

作者： Hui LI~2,Nmg-ling SUN~(2,4),Jin WANG~3.Ai-jun LIU~3.Ding-feng SU~(3.4)~2department of Cardiology,peking university People's {3.,beijing 100044,china ~3.0} of Pharmacology,Second MilitaryMedical university,Shanghai 20043.,china department of Cardiology Peking University People's Hospital Beijing China department of Pharmacology Second Military Medical University Shanghai China

Aim:To investigate whether the circadian expression of central clock genes andangiotensin Ⅱ type 1 (AT1) receptors was altered in sinoaortic-denervated (SAD)***:Male Sprague-Dawley rats underwent sinoaortic denervation or asham operation at the age of 12 *** weeks after the operation,bloodpressure and heart period were measured in the conscious state in a group ofsham-operated (n=10) and SAD rats (n=9).Rest SAD and sham-operated ratswere divided into 6 groups (n=6 in each group).The suprachiasmatic nuclei (SCN)tissues were taken every 4 h throughout the day from each group for the determi-nation of the mRNA expression of clock genes (Per2 and Bmal1) and the AT1receptor by RT-PCR;the protein expression of Per2 and Bmal1 was determined byWestern ***:Blood pressure levels in the SAD rats were similar tothose of the sham-operated ***,blood pressure variabilities signifi-cantly increased in the SAD rats compared with the sham-operated *** variation of clock genes in the SCN of the sham-operated rats was char-acterized by a marked increase in the mRNA and protein expression during ***2 and Bmal1 mRNA levels were significantly lower in the SAD rats,especially during dark *** blot analysis confirmed an attenuation ofthe circadian rhythm of the 2 clock proteins in the SCN of the SAD ***1receptor mRNA expressions in the SCN were abnormally upregulated in the lightphase,changed to a 12-h cycle in the SAD ***:The circadian varia-tion of the 2 central clock genes was attenuated in the SAD *** baroreflexdysfunction also induced a disturbance in the expression of AT1 receptors in theSCN.

关键词： circadian rhythm arterial baroreflex clock genes sinoaortic denervation reninangiotensin system

Multiuser detection algorithm based on belief propagation in multiple-input multiple-output systems

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Science in china(Series F) 2004年第3期47卷 384-393页

作者： JIANG Wei XIANG Haige department of Electronics, peking university, beijing 100871, {3. department of Electronics Peking University Beijing China

In MIMO (multiple-input, multiple-output) systems, signals from differenttransmitting antennas interfere at each receiving antenna and multiuser detection (MUD)algorithms may be adopted to improve the system performance. This paper proposes anovel multiuser detection algorithm in MIMO systems based on the idea of 'beliefpropagation' which has achieved great accomplishment in decoding of low-densityparity-check codes. The proposed algorithm has a low computation complexityproportional to the square of transmitting/receiving antenna number. Simulation resultsshow that under low signal-to-noise ratio (SNR) circumstances, the proposed algorithmoutperforms the traditional linear minimum mean square error (MMSE) detector while itencounters a 'floor' of bit error rate under high SNR circumstances. So the proposedalgorithm is applicable to MIMO systems with channel coding and decoding. Although inthis paper the proposed algorithm is derived in MIMO systems, obviously it can be appliedto ordinary code-division multiple access (CDMA) systems.

关键词： multiple-input multiple-output belief propagation multiuser detection

The localization of 1-cohomology of transitive Lie algebroids

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Science china Mathematics 2006年第2期49卷 277-288页

作者： CHEN Zhuo & LIU Zhangju department of Mathematics, Capital Normal university, beijing 10003., {3. School of Mathematical Science, peking university, beijing 100871, {3. department of Mathematics Capital Normal University Beijing China School of Mathematical Science Peking University Beijing China

For a transitive Lie algebroid A on a connected manifold M and its representation on a vector bundle F, we define a morphism of cohomology groups rk: Hk(A,F) → Hk(Lx,Fx), called the localization map, where Lx is the adjoint algebra at x ∈ M. The main result in this paper is that if M is simply connected, or H (LX,FX) is trivial, then T is injective. This means that the Lie algebroid 1-cohomology is totally determined by the 1-cohomology of its adjoint Lie algebra in the above two cases.

关键词： transitive Lie algebroid representation cohomology localization.