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蛋白质结构域划分方法及在线服务综述 预览
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作者 王燕 石强 薛志东 《广州大学学报:自然科学版》 CAS 2019年第1期20-29,共10页
蛋白质结构域是研究蛋白质结构、功能与进化的基本单位,不同的结构域可组合出更为复杂的蛋白质分子.划分蛋白质结构域后,可以从结构域的角度研究蛋白质的结构、功能与进化,降低了研究复杂度.根据已知结构的蛋白质统计,有约40%的为多结... 蛋白质结构域是研究蛋白质结构、功能与进化的基本单位,不同的结构域可组合出更为复杂的蛋白质分子.划分蛋白质结构域后,可以从结构域的角度研究蛋白质的结构、功能与进化,降低了研究复杂度.根据已知结构的蛋白质统计,有约40%的为多结构域蛋白质,其中还存在一级结构上不临近的氨基酸序列出现在同一个结构域的情况,即不连续结构域.文章给出了当前国内外有关蛋白质结构域边界预测、不连续结构域检测及结构域数据库与在线服务的研究进展,供相关研究者参考. 展开更多
关键词 蛋白质 结构域 不连续结构域 预测 在线服务
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Comparative analysis of C-type lectin domain proteins in the ghost moth, Thitarodes xiaojinensis (Lepidoptera: Hepialidae)
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作者 Qian Meng Ji-Hong Zhang +5 位作者 Huan Zhang Gui-Ling Zhou Ruo-Yao Ni Yan-Ni Zhao Qi-Lian Qin Zhen Zou 《昆虫科学:英文版》 SCIE CAS CSCD 2019年第3期453-465,共13页
Insects have a large family of C-type lectins involved in cell adhesion, pathogen recognition and activation of immune responses. In this study, 32 transcripts encoding C-type lectin domain proteins (CTLDPs) were iden... Insects have a large family of C-type lectins involved in cell adhesion, pathogen recognition and activation of immune responses. In this study, 32 transcripts encoding C-type lectin domain proteins (CTLDPs) were identified from the Thitarodes xiaojinensis transcriptome. According to their domain structures, six CTLDPs with one carbohydraterecognition domain (CRD) were classified into the CTL-S subfamily. The other 23 CTLDPs with two CRDs were grouped into the immulectin (IML) subfamily. The remaining three with extra regulatory domains were sorted into the CTL-X subfamily. Phylogenetic analysis showed that CTL-S and CTL-X members from different insects could form orthologous groups. In contrast, no T. xiaojinensis IML orthologues were found in other insects. Remarkable lineage-specific expansion in this subfamily was observed reflecting that these CTLDPs, as important receptors, have evolved diversified members in response to a variety of microbes. Prediction of binding ligands revealed that T. xiaojinensis, a coldadapted species, conserved the ability of CRDs to combine with Ca^2+ to keep its receptors from freezing. Comparative analysis of induction of CTLDP genes after different immune challenges indicated that IMLs might play critical roles in immune defenses. This study examined T. xiaojinensis CTLDPs and provides a basis for further studies of their characteristics. 展开更多
关键词 binding ligand carbohydrate-recognition DOMAIN C-type LECTIN DOMAIN protein expression PROFILING PHYLOGENETIC feature Thitarodes xiaojinensis
A modified domain reduction method for numerical simulation of wave propagation in localized regions 预览
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作者 Luo Chao Lou Menglin +1 位作者 Gui Guoqing Wang Hao 《地震工程与工程振动:英文版》 SCIE EI CSCD 2019年第1期35-52,共18页
A modified domain reduction method(MDRM) that introduces damping terms to the original DRM is presented in this paper. To verify the proposed MDRM and compare the computational accuracy of these two methods, a numeric... A modified domain reduction method(MDRM) that introduces damping terms to the original DRM is presented in this paper. To verify the proposed MDRM and compare the computational accuracy of these two methods, a numerical test is designed. The numerical results of the MDRM and DRM are compared using an extended meshed model. The results show that the MDRM significantly improved the computational accuracy of the DRM. Then, the MDRM is compared with two existing conventional methods, namely Liao’s transmitting boundary and viscous-spring boundary with Liu’s method. The MDRM shows its great advancement in computational accuracy, stability and range of applications. This paper also discusses the influence of boundary location on computational accuracy. It can be concluded that smaller models tend to have larger errors. By introducing two dimensionless parameters, φ1 and φ2, the rational distance between the observation point and the MDRM boundary is suggested. When φ1 >2 or φ2>13, the relative PGA error can be limited to 5%. In practice, the appropriate model size can be chosen based on these two parameters to achieve desired computational accuracy. 展开更多
关键词 MODIFIED DOMAIN REDUCTION METHOD DOMAIN REDUCTION METHOD VISCOUS BOUNDARY VISCOUS spring BOUNDARY transmitting BOUNDARY wave propagation
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Biholomorphic Mappings and the Extension Operators on New Hartogs Domains
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作者 Yan Yan CUI Chao Jun WANG Hao LIU 《数学学报:英文版》 SCIE CSCD 2019年第5期671-689,共19页
In this paper, we generalize the Roper-Suffridge operator on the extended Hartogs domains. By using the geometric properties and the growth theorems of subclasses of biholomorphic mappings, we obtain the generalized o... In this paper, we generalize the Roper-Suffridge operator on the extended Hartogs domains. By using the geometric properties and the growth theorems of subclasses of biholomorphic mappings, we obtain the generalized operators preserve the properties of parabolic and spirallike mappings of type β and order ρ, SΩ*(β, A, B), almost starlike mapping of complex order λ on ΩN under different conditions, and thus we get the corresponding results on the unit ball Bn in Cn. The conclusions lead to some known results. 展开更多
关键词 Biholomorphic MAPPING Roper-Suffridge OPERATOR Hartogs DOMAIN
细胞分裂周期蛋白42结构域突变真核表达质粒的构建与鉴定 预览
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作者 李振玲 王帝 +1 位作者 宋远见 王玉兰 《解剖学杂志》 CAS 2019年第3期249-252,共4页
目的:构建细胞分裂周期蛋白(Cdc42)的结构域突变质粒,即鸟嘌呤核苷酸交换因子(GEF)结构域突变质粒。方法:根据NCBI中小鼠Cdc42全长cDNA序列找到结构域GEF,将GEF的氨基酸突变成丙氨酸,根据突变后的序列设计引物,PCR扩增得到目的片段588bp... 目的:构建细胞分裂周期蛋白(Cdc42)的结构域突变质粒,即鸟嘌呤核苷酸交换因子(GEF)结构域突变质粒。方法:根据NCBI中小鼠Cdc42全长cDNA序列找到结构域GEF,将GEF的氨基酸突变成丙氨酸,根据突变后的序列设计引物,PCR扩增得到目的片段588bp,限制性内切酶EcoRI和HindⅢ双酶切后插入到编码红色荧光蛋白(RFP)和his标签的真核表达载体PM-his-RFP中,构建PM-his-Cdc42(GEF)-RFP重组质粒,进行酶切电泳及DNA测序验证。用脂质体介导方法将重组质粒瞬时转染HT22细胞,通过荧光显微镜观察转染效率。结果:经酶切及测序结果显示突变后结构域插入的位置和序列正确,成功构建Cdc42蛋白GEF结构域突变质粒;荧光结果表明,重组质粒顺利转染HT22细胞。结论:成功构建的Cdc42结构域突变质粒为Cdc42蛋白的功能研究提供有效的操作工具。 展开更多
关键词 细胞分裂周期蛋白 鸟嘌呤核苷酸交换因子 结构域 真核表达质粒 突变
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Stacking transition in rhombohedral graphite
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作者 Tataiana Latychevskaia Seok-Kyun Son +8 位作者 Yaping Yang Dale Chancellor Michael Brown Servet Ozdemir Ivan Madan Gabriele Berruto Fabrizio Carbone Artem Mishchenko Kostya S. Novoselov 《物理学前沿:英文版》 SCIE CSCD 2019年第1期67-73,共7页
Few-layer graphene (FLG) has recently been intensively investigated for its variable electronic properties, which are defined by a local atomic arrangement. While the most natural arrangement of layers in FLG is ABA (... Few-layer graphene (FLG) has recently been intensively investigated for its variable electronic properties, which are defined by a local atomic arrangement. While the most natural arrangement of layers in FLG is ABA (Bernal) stacking, a metastable ABC (rhombohedral) stacking, characterized by a relatively high-energy barrier, can also occur. When both types of stacking occur in one FLG device, the arrangement results in an in-plane heterostructure with a domain wall (DW). In this paper, we present two approaches to demonstrate that the ABC stacking in FLG can be controllably and locally turned into the ABA stacking. In the first approach, we introduced Joule heating, and the transition was characterized by 2D peak Raman spectra at a submicron spatial resolution. The transition was initiated in a small region, and then the DW was controllably shifted until the entire device became ABA stacked. In the second approach, the transition was achieved by illuminating the ABC region with a train of 790-nm-wavelength laser pulses, and the transition was visualized by transmission electron microscopy in both diffraction and dark-field imaging modes. Further, using this approach, the DW was visualized at a nanoscale spatial resolution in the dark-field imaging mode. 展开更多
关键词 graphene GRAPHITE van der WAALS HETEROSTRUCTURES domain wall Raman spectroscopy transmission ELECTRON microscopy ELECTRON diffraction structural TRANSITION
Alanine-substituted mutant on Gly^373 and Asn^375 of Cry1Ai-h-loop 2 causes reduction in both toxicity and binding against Helicoverpa armigera 预览
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作者 LIU Yu-xiao ZHOU Zi-shan +2 位作者 LIANG Ge-mei SONG Fu-ping ZHANG Jie 《农业科学学报:英文版》 SCIE CAS CSCD 2019年第5期1064-1071,共8页
Cry1Ai-h-loop 2 is a mutant of Cry1Ai constructed by exchanging loop 2 from Cry1Ah protein and shows insecticidal activity against Helicoverpa armigera. The toxicity of Cry1 Ai-h-loop 2, in contrast to the very low to... Cry1Ai-h-loop 2 is a mutant of Cry1Ai constructed by exchanging loop 2 from Cry1Ah protein and shows insecticidal activity against Helicoverpa armigera. The toxicity of Cry1 Ai-h-loop 2, in contrast to the very low toxicity of Cry1Ai, is closely associated with the eleven residues in the loop 2 region. To characterize the key sites of loop 2 in Cry1Ai-h-loop 2, alaninesubstituted mutants were generated. The toxicity of these mutants against H. armigera indicated that dual-mutant on Gly^373 and Asn^375 caused a significant decrease in toxic activity. ELISA binding and competition binding assays demonstrated that the reduction of toxicity in the mutant of interest was correlated with decreased binding affinity. 展开更多
关键词 Bacillus THURINGIENSIS Cry1Ai Domain Ⅱ-loop2 HELICOVERPA ARMIGERA BINDING AFFINITY
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Terahertz radiation of a butterfly-shaped photoconductive antenna(invited) 预览
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作者 Jitao Zhang Mingguang Tuo +3 位作者 Min Liang Wei-Ren Ng Michael EGehm Hao Xin 《红外与激光工程》 EI CSCD 北大核心 2019年第4期9-17,共9页
The terahertz(THz) far-field radiation properties of a butterfly-shaped photoconductive antenna(PCA) were experimentally studied using a home-built THz time-domain spectroscopy(THz-TDS) setup.To distinguish the contri... The terahertz(THz) far-field radiation properties of a butterfly-shaped photoconductive antenna(PCA) were experimentally studied using a home-built THz time-domain spectroscopy(THz-TDS) setup.To distinguish the contribution of in-gap photocurrent and antenna structure to far-field radiation,polarization-dependent THz field was measured and quantified as the illuminating laser beam moved along the bias field within the gap region of electrodes. The result suggests that, although the far-field THz radiation originates from the in-gap photocurrent, the antenna structure of butterfly-shaped PCA dominates the overall THz radiation. In addition, to explore the impact of photoconductive material,radiation properties of butterfly-shaped PCAs fabricated on both low-temperature-grown GaAs(LT-GaAs) and semi-insulating GaAs(Si-GaAs) were characterized and compared. Consistent with previous experiments, it is observed that while Si-GaAs-based PCA can emit higher THz field than LT-GaAs-based PCA at low laser power, it would saturate more severely as laser power increased and eventually be surpassed by LT-GaAs-based PCA. Beyond that, it is found the severe saturation effect of Si-GaAs was due to the longer carrier lifetime and higher carrier mobility, which was confirmed by the numerical simulation. 展开更多
关键词 TERAHERTZ PHOTOCONDUCTIVE ANTENNA BUTTERFLY time domain SPECTROSCOPY
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LOW MACH NUMBER LIMIT OF A COMPRESSIBLE NON-ISOTHERMAL NEMATIC LIQUID CRYSTALS MODEL 预览
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作者 樊继山 栗付才 《数学物理学报:B辑英文版》 SCIE CSCD 2019年第2期449-460,共12页
In this paper, we study the low Mach number limit of a compressible nonisothermal model for nematic liquid crystals in a bounded domain. We establish the uniform estimates with respect to the Mach number, and thus pro... In this paper, we study the low Mach number limit of a compressible nonisothermal model for nematic liquid crystals in a bounded domain. We establish the uniform estimates with respect to the Mach number, and thus prove the convergence to the solution of the incompressible model for nematic liquid crystals. 展开更多
关键词 COMPRESSIBLE NON-ISOTHERMAL liquid CRYSTALS BOUNDED domain low MACH number LIMIT
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Solution structure of the RNA recognition domain of METTL3-METTL14 N^6-methyladenosine methyltransferase
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作者 Jinbo Huang Xu Dong +8 位作者 Zhou Gong Ling-Yun Qin Shuai Yang Yue-Ling Zhu Xiang Wang Delin Zhang Tingting Zou Ping Yin Chun Tang 《蛋白质与细胞:英文版》 SCIE CAS CSCD 2019年第4期272-284,共13页
N^6-methyladenosine(m6A),a ubiquitous RNA modification,is installed by METTL3-METTL14 complex.The structure of the heterodimeric complex between the methyltransferase domains(MTDs)of METTL3 and METTL14 has been previo... N^6-methyladenosine(m6A),a ubiquitous RNA modification,is installed by METTL3-METTL14 complex.The structure of the heterodimeric complex between the methyltransferase domains(MTDs)of METTL3 and METTL14 has been previously determined.However,the MTDs alone possess no enzymatic activity.Here we present the solution structure for the zinc finger domain(ZFD)of METTL3,the inclusion of which fulfills the methyltransferase activity of METTL3-METTL14.We show that the ZFD specifically binds to an RNA containing 5'-GGACU-3'consensus sequence,but does not to one without.The ZFD thus serves as the target recognition domain,a structural feature previously shown for DNA methyltransferases,and cooperates with the MTDs of METTL3-METTL14 for catalysis.However,the interaction between the ZFD and the specific RNA is extremely weak,with the binding affinity at several hundred micromolar under physiological conditions.The ZFD contains two CCCH-type zinc fingers connected by an anti-parallel P-sheet.Mutational analysis and NMR titrations have mapped the functional interface to a contiguous surface.As a division of labor,the RNA-binding interface comprises basic residues from zinc finger 1 and hydrophobic residues fromβ-sheet and zinc finger 2.Further we show that the linker between the ZFD and MTD of METTL3 is flexible but partially folded,which may permit the cooperation between the two domains during catalysis.Together,the structural characterization of METTL3 ZFD paves the way to elucidate the atomic details of the entire process of RNA m6A modification. 展开更多
关键词 RNA modification N^6-methyladenosine METTL3 target recognition DOMAIN zinc FINGER PARAMAGNETIC RELAXATION enhancement
Reductivity and bundle shifts 预览
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作者 XU An-jian 《高校应用数学学报:英文版(B辑)》 SCIE CSCD 2019年第1期27-32,共6页
For the Hardy space HE^2(R)over a flat unitary vector bundle E on a finitely connected domain R,let TE be the bundle shift as[3].If B is a reductive algebra containing every operator(TE)for any rational function with ... For the Hardy space HE^2(R)over a flat unitary vector bundle E on a finitely connected domain R,let TE be the bundle shift as[3].If B is a reductive algebra containing every operator(TE)for any rational function with poles outside of R,then B is self adjoint. 展开更多
关键词 reductivity BUNDLE SHIFT multiply-connected DOMAIN
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水稻三结构域多铜氧化酶基因家族生物信息学分析
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作者 王有成 谭炎宁 +4 位作者 张超 殷小林 何强 肖应辉 邓华凤 《分子植物育种》 CAS CSCD 北大核心 2019年第5期1385-1392,共8页
三结构域多铜氧化酶是生物体内非常重要的金属氧化酶,对机体生长和发育具有重要影响。为了系统地了解水稻三结构域多铜氧化酶基因家族的基本情况,本研究运用生物信息学方法对其成员进行了预测和分析;研究发现,以拟南芥三结构域多铜氧化... 三结构域多铜氧化酶是生物体内非常重要的金属氧化酶,对机体生长和发育具有重要影响。为了系统地了解水稻三结构域多铜氧化酶基因家族的基本情况,本研究运用生物信息学方法对其成员进行了预测和分析;研究发现,以拟南芥三结构域多铜氧化酶基因At5g21105为靶序列,利用BlastP为工具在水稻基因组中共搜索到38个同源基因;这些基因的蛋白产物都依次含有Cu-oxidase3、Cu-oxidase和Cu-oxidase2三种结构域,各结构域中含有铜离子结合位点,二级结构具有α-螺旋和β-转角等基本特征,特推断它们都属于三结构域多铜氧化酶家族成员;进一步地,根据同源性程度将水稻多铜氧化酶基因家族成员划分为ClassⅠ和ClassⅡ两个亚家族,其中ClassⅠ包含31个基因,ClassⅡ包含7个基因。这些研究结果为进一步研究水稻多铜氧化酶基因家族成员的功能提供了参考依据。 展开更多
关键词 水稻 多铜氧化酶 基因家族 结构域 生物信息学分析
Screening the RFX6-DNA binding domain for potential genetic variants in patients with type 2 diabetes 预览
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作者 Ismail S Mahmoud Ayat Homsi +6 位作者 Hamzeh J Al-Ameer Jihad Alzyoud Mais Darras Mohammad Al Shhab Malek Zihlif Ma’mon M Hatmal Walhan Alshaer 《世界糖尿病杂志:英文版(电子版)》 2019年第3期181-187,共7页
BACKGROUND The regulatory factor X6 (RFX6), a member of regulatory factor X family, is known to play a key role in the development and differentiation of pancreatic beta cells as well as insulin production and secreti... BACKGROUND The regulatory factor X6 (RFX6), a member of regulatory factor X family, is known to play a key role in the development and differentiation of pancreatic beta cells as well as insulin production and secretion. However, the potential role of RFX6 in type 2 diabetes (T2D) is still unclear. AIM Recent studies have indicated that RFX6 binding to DNA could be disrupted in diabetes. Therefore, in this study we investigated whether genetic mutations are present in the DNA binding domain of RFX6 gene that could abrogate its function in T2D. METHODS A cohort of T2D patients was enrolled in this study, and the gene encoding the DNA binding domain of RFX6 was amplified by polymerase chain reaction and then analysed by direct DNA sequencing. RESULTS The DNA sequence analysis revealed the absence of any exonic mutation. However, we have identified a new heterozygous single nucleotide polymorphism (IVS6+31 C>T) in the intronic region of DNA binding domain gene that is present in 9.2% and 8.5% of diabetic and control people, respectively (P = 0.97).CONCLUSION We report the absence of any significant genetic variant that could affect the function of RFX6-DNA binding domain in T2D. 展开更多
关键词 REGULATORY factor X6 GENETIC VARIANT DIABETES DNA BINDING domain
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基于结构域理化性质的蛋白质相互作用方向预测 预览
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作者 卫博翔 焦雄 《太原理工大学学报》 CAS 北大核心 2019年第4期536-540,共5页
为了更好地理解蛋白质相互作用,用蛋白质相互作用间信号传递方向进一步注释蛋白质相互作用网络,提出了一种基于结构域理化性质预测蛋白质相互作用方向的方法。首先提取蛋白质结构域的10种理化性质,构成表示方向信息的特征向量;然后建立... 为了更好地理解蛋白质相互作用,用蛋白质相互作用间信号传递方向进一步注释蛋白质相互作用网络,提出了一种基于结构域理化性质预测蛋白质相互作用方向的方法。首先提取蛋白质结构域的10种理化性质,构成表示方向信息的特征向量;然后建立支持向量机预测模型,并利用网格搜索对模型进行参数寻优;最后用拥有最优参数的模型进行预测。实验结果表明,该模型准确率达到88.17%,AUC值为0.837.与PIDS方法比较结果表明,蛋白质结构域的10种理化性质能够有效用于蛋白质相互作用方向的预测,为预测蛋白质相互作用方向提供了一种新思路。 展开更多
关键词 蛋白质 相互作用 结构域 理化特性 支持向量机 方向预测
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Knowledge domain and emerging trends in Alzheimer's disease:a scientometric review based on CiteSpace analysis 预览
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作者 Shuo Liu Ya-Ping Sun +1 位作者 Xu-Ling Gao Yi Sui 《中国神经再生研究:英文版》 SCIE CAS CSCD 2019年第9期1643-1650,共8页
Alzheimer’s disease is the most common cause of dementia.It is an increasingly serious global health problem and has a significant impact on individuals and society.However,the precise cause of Alzheimer’s disease i... Alzheimer’s disease is the most common cause of dementia.It is an increasingly serious global health problem and has a significant impact on individuals and society.However,the precise cause of Alzheimer’s disease is still unknown.In this study,11,748 Web-of-Science-indexed manuscripts regarding Alzheimer’s disease,all published from 2015 to 2019,and their 693,938 references were analyzed.A document co-citation network map was drawn using CiteSpace software.Research frontiers and development trends were determined by retrieving subject headings with apparent changing word frequency trends,which can be used to forecast future research developments in Alzheimer’s disease. 展开更多
关键词 NERVE REGENERATION Alzheimer’sdisease NEUROPROTECTION mapping KNOWLEDGE domain Web of Science CiteSpace neural REGENERATION
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Distributed Vibration Sensor With Laser Phase-Noise Immunity by Phase-Extraction φ-OTDR
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作者 Yuying SHAO Huanhuan LIU +5 位作者 Peng PENG Fufei PANG Guoqin YU Zhen CHEN Na CHEN Tingyun WANG 《光子传感器:英文版》 EI CAS CSCD 2019年第3期223-229,共7页
We have demonstrated a distributed vibration sensor based on phase-sensitive optical time-domain reflectometer (φ-OTDR) system exhibiting immunity to the laser phase noise. Two laser sources with different linewidth ... We have demonstrated a distributed vibration sensor based on phase-sensitive optical time-domain reflectometer (φ-OTDR) system exhibiting immunity to the laser phase noise. Two laser sources with different linewidth and phase noise levels are used in the φ-OTDR system, respectively. Based on the phase noise power spectrum density of both lasers, the laser phase is almost unchanged during an extremely short period of time, hence, the impact of phase noise can be suppressed effectively through phase difference between the Rayleigh scattered light from two adjacent sections of the fiber which define the gauge length. Based on the phase difference method, the external vibration can be located accurately at 41.01 km by the(φ-OTDR system incorporating these two lasers. Meanwhile, the average signal-to-noise ratio (SNR) of the retrieved vibration signal by using Laser I is found to be -37.7 dB, which is comparable to that of -37.5 dB by using Laser II although the linewidth and the phase noise level of the two lasers are distinct. The obtained results indicate that the phase difference method can enhance the performance of(φ-OTDR system with laser phase-noise immunity for distributed vibration sensing, showing potential application in oil-gas pipeline monitoring, perimeter security, and other fields. 展开更多
关键词 DISTRIBUTED vibration SENSING optical time domain REFLECTOMETER fiber sensor PHASE noise
Domain walls and their interactions in a two-component Bose–Einstein condensate
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作者 孟令正 秦艳红 +1 位作者 赵立臣 杨战营 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第6期99-104,共6页
We investigate domain wall excitations in a two-component Bose–Einstein condensate with two-body interactions and pair-transition effects. It is shown that domain wall excitations can be described exactly by kink and... We investigate domain wall excitations in a two-component Bose–Einstein condensate with two-body interactions and pair-transition effects. It is shown that domain wall excitations can be described exactly by kink and anti-kink excitations in each component. The domain wall solutions are given analytically, which exist with different conditions compared with the domain wall reported before. Bubble-droplet structure can be also obtained from the fundamental domain wall, and their interactions are investigated analytically. Especially, domain wall interactions demonstrate some striking particle transition dynamics. These striking transition effects make the domain wall admit quite different collision behavior, in contrast to the collision between solitons or other nonlinear waves. The collisions between kinks induce some phase shift, which makes the domain wall change greatly. Their collisions can be elastic or inelastic with proper combination of fundamental domain walls. These characters can be used to manipulate one domain wall by interacting with other ones. 展开更多
关键词 domain wall pair-transition MULTI-COMPONENT Bose–Einstein CONDENSATE
The smoothed finite element method (S-FEM):A framework for the design of numerical models for desired solutions
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作者 Gui-Rong Liu 《结构与土木工程前沿:英文版》 EI CSCD 2019年第2期456-477,共22页
The smoothed finite element method (S-FEM) was originated by G R Liu by combining some meshfree techniques with the well-established standard finite element method (FEM). It has a family of models carefully designed w... The smoothed finite element method (S-FEM) was originated by G R Liu by combining some meshfree techniques with the well-established standard finite element method (FEM). It has a family of models carefully designed with innovative types of smoothing domains. These models are found having a number of important and theoretically profound properties. This article first provides a concise and easy-to-follow presentation of key formulations used in the S-FEM. A number of important properties and unique features of S-FEM models are discussed in detail, including 1) theoretically proven softening effects;2) upper-bound solutions;3) accurate solutions and higher convergence rates;4) insensitivity to mesh distortion;5) Jacobian?free;6) volumetric-locking-free;and most importantly 7) working well with triangular and tetrahedral meshes that can be automatically generated. The S-FEM is thus ideal for automation in computations and adaptive analyses, and hence has profound impact on Al-assisted modeling and simulation. Most importantly, one can now purposely design an S-FEM model to obtain solutions with special properties as wish, meaning that S-FEM offers a framework for design numerical models with desired properties. This novel concept of numerical model demand may drastically change the landscape of modeling and simulation. Future directions of research are also provided. 展开更多
关键词 computational METHOD FINITE ELEMENT METHOD smoothed FINITE ELEMENT METHOD strain SMOOTHING technique SMOOTHING domain weakened weak form solid mechanics SOFTENING effect upper bound solution
Task planning in robotics:an empirical comparison of PDDL-and ASP-based systems
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作者 Yu-qian JIANG Shi-qi ZHANG +1 位作者 Piyush KHANDELWAL Peter STONE 《信息与电子工程前沿:英文版》 SCIE EI CSCD 2019年第3期363-373,共11页
Robots need task planning algorithms to sequence actions toward accomplishing goals that are impossible through individual actions. Off-the-shelf task planners can be used by intelligent robotics practitioners to solv... Robots need task planning algorithms to sequence actions toward accomplishing goals that are impossible through individual actions. Off-the-shelf task planners can be used by intelligent robotics practitioners to solve a variety of planning problems. However, many different planners exist, each with different strengths and weaknesses,and there are no general rules for which planner would be best to apply to a given problem. In this study, we empirically compare the performance of state-of-the-art planners that use either the planning domain description language(PDDL) or answer set programming(ASP) as the underlying action language. PDDL is designed for task planning, and PDDL-based planners are widely used for a variety of planning problems. ASP is designed for knowledge-intensive reasoning, but can also be used to solve task planning problems. Given domain encodings that are as similar as possible, we find that PDDL-based planners perform better on problems with longer solutions,and ASP-based planners are better on tasks with a large number of objects or tasks in which complex reasoning is required to reason about action preconditions and effects. The resulting analysis can inform selection among general-purpose planning systems for particular robot task planning domains. 展开更多
关键词 TASK PLANNING ROBOTICS PLANNING domain description language (PDDL) ANSWER set PROGRAMMING (ASP)
卡普利加(Kaprekar)数的构造和推广 预览
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作者 李长明 《高等数学研究》 2019年第1期16-25,共10页
本文首先在位数相同的数集中,定义一种新的运算——循环进位法,并证明循环进位法的加法、乘法使位数相同的数集构成群、环.在此环中,我们又给出卡普利加数的定义,并在环的主理想中,推出它的构造原理和算法.最后我们把“一分为二(卡普利... 本文首先在位数相同的数集中,定义一种新的运算——循环进位法,并证明循环进位法的加法、乘法使位数相同的数集构成群、环.在此环中,我们又给出卡普利加数的定义,并在环的主理想中,推出它的构造原理和算法.最后我们把“一分为二(卡普利加数)”推广到“一分为N”. 展开更多
关键词 卡普利加数 广义位数(编码位数) 循环进位 分段相加 主理想 卡普利加数的推广--“一分为N”
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