747 research outputs found
Dan jin shu yu shuang jin shu na mi jing ti cai liao: he cheng ji biao mian deng li zi ti gong zhen te xing
No full textLi, Qian = 單金屬與雙金屬納米晶體材料 : 合成及表面等離子體共振特性 / 李倩.Thesis Ph.D. Chinese University of Hong Kong 2014.Includes bibliographical references.Abstracts also in Chinese.Title from PDF title page (viewed on 20, September, 2016).Li, Qian = Dan jin shu yu shuang jin shu na mi jing ti cai liao : he cheng ji biao mian deng li zi ti gong zhen te xing / Li Qian
A comprehensive assessment of empirical potentials for carbon materials
No full text© 2021 Author(s).Carbon materials and their unique properties have been extensively studied by molecular dynamics, thanks to the wide range of available carbon bond order potentials (CBOPs). Recently, with the increase in popularity of machine learning (ML), potentials such as Gaussian approximation potential (GAP), trained using ML, can accurately predict results for carbon. However, selecting the right potential is crucial as each performs differently for different carbon allotropes, and these differences can lead to inaccurate results. This work compares the widely used CBOPs and the GAP-20 ML potential with density functional theory results, including lattice constants, cohesive energies, defect formation energies, van der Waals interactions, thermal stabilities, and mechanical properties for different carbon allotropes. We find that GAP-20 can more accurately predict the structure, defect properties, and formation energies for a variety of crystalline phase carbon compared to CBOPs. Importantly, GAP-20 can simulate the thermal stability of C60 and the fracture of carbon nanotubes and graphene accurately, where CBOPs struggle. However, similar to CBOPs, GAP-20 is unable to accurately account for van der Waals interactions. Despite this, we find that GAP-20 outperforms all CBOPs assessed here and is at present the most suitable potential for studying thermal and mechanical properties for pristine and defective carbon.11Nsciescopu
Single Mode Fibers for Cascaded Higher-order Soliton Compression
No full textDetailed fiber design of single mode fibers for two-stage higher-order soliton compression at 1550 nm is presented for the first time. A compression factor of 87.8 has been achieved.National Natural Science Foundation of China [61307051]; Shenzhen Technology and Innovation Council [JCYJ20140419131807789, KQCX2014052115012744]CPCI-S(ISTP
The incidence of liver injury in Uyghur patients treated for TB in Xinjiang Uyghur autonomous region, China, and its association with hepatic enzyme polymorphisms nat2, cyp2e1, gstm1 and gstt1.
No full textBACKGROUND AND OBJECTIVE: Of three first-line anti-tuberculosis (anti-TB) drugs, isoniazid is most commonly associated with hepatotoxicity. Differences in INH-induced toxicity have been attributed to genetic variability at several loci, NAT2, CYP2E1, GSTM1and GSTT1, that code for drug-metabolizing enzymes. This study evaluated whether the polymorphisms in these enzymes were associated with an increased risk of anti-TB drug-induced hepatitis in patients and could potentially be used to identify patients at risk of liver injury. METHODS AND DESIGN: In a cross-sectional study, 2244 tuberculosis patients were assessed two months after the start of treatment. Anti-TB drug-induced liver injury (ATLI) was defined as an ALT, AST or bilirubin value more than twice the upper limit of normal. NAT2, CYP2E1, GSTM1 and GSTT1 genotypes were determined using the PCR/ligase detection reaction assays. RESULTS: 2244 patients were evaluated, there were 89 cases of ATLI, a prevalence of 4% 9 patients (0.4%) had ALT levels more than 5 times the upper limit of normal. The prevalence of ATLI was greater among men than women, and there was a weak association with NAT2*5 genotypes, with ATLI more common among patients with the NAT2*5*CT genotype. The sensitivity of the CT genotype for identifying patients with ATLI was 42% and the positive predictive value 5.9%. CT ATLI was more common among slow acetylators (prevalence ratio 2.0 (95% CI 0.95,4.20) )compared to rapid acetylators. There was no evidence that ATLI was associated with CYP2E1 RsaIc1/c1genotype, CYP2E1 RsaIc1/c2 or c2/c2 genotypes, or GSTM1/GSTT1 null genotypes. CONCLUSIONS: In Xinjiang Uyghur TB patients, liver injury was associated with the genetic variant NAT2*5, however the genetic markers studied are unlikely to be useful for screening patients due to the low sensitivity and low positive predictive values for identifying persons at risk of liver injury
Loss of TSLC1 causes male infertility due to a defect at the spermatid stage of spermatogenesis.
No full textTumor suppressor of lung cancer 1 (TSLC1), also known as SgIGSF, IGSF4, and SynCAM, is strongly expressed in spermatogenic cells undergoing the early and late phases of spermatogenesis (spermatogonia to zygotene spermatocytes and elongating spermatids to spermiation). Using embryonic stem cell technology to generate a null mutation of Tslc1 in mice, we found that Tslc1 null male mice were infertile. Tslc1 null adult testes showed that spermatogenesis had arrested at the spermatid stage, with degenerating and apoptotic spermatids sloughing off into the lumen. In adult mice, Tslc1 null round spermatids showed evidence of normal differentiation (an acrosomal cap and F-actin polarization indistinguishable from that of wild-type spermatids); however, the surviving spermatozoa were immature, malformed, found at very low levels in the epididymis, and rarely motile. Analysis of the first wave of spermatogenesis in Tslc1 null mice showed a delay in maturation by day 22 and degeneration of round spermatids by day 28. Expression profiling of the testes revealed that Tslc1 null mice showed increases in the expression levels of genes involved in apoptosis, adhesion, and the cytoskeleton. Taken together, these data show that Tslc1 is essential for normal spermatogenesis in mice
Direct imaging of self-assembly behaviors of colloids: from the microscale plates to the nanoscale cubes
No full textMicroscale and nanoscale colloidal particle self-assembly is widely studied to establish the design rules towards ordered structures and used as atomic model systems for phase transition studies such as crystallization and growth. The well-established synthetic library enables the synthesis of colloidal particles with controllable size, morphology, and surface chemistry, which dictates their interactions for self-assembly. This dissertation focuses on studying a promising yet underexplored colloidal building blocks: anisometric colloids and developing direct imaging tool of liquid-phase transmission electron microscopy (TEM) to visualize and quantify the less-explored nanoparticle self-assembly dynamics in solution. I begin by engineering highly directional interactions of micron-sized silver plates through colloidal synthesis and surface functionalization, to induce their co-assembly with patchy spheres into complex, 2D architectures. Utilizing a combination of direct optical microscopy imaging, theoretical modeling, and automated single particle tracking, I further demonstrate an unconventional crystallization pathway into 3D hierarchical lattices from polydisperse colloids. Then I focus on a foundationally new imaging tool known as liquid-phase TEM for in-situ imaging of otherwise inaccessible solution-phase nanoparticle self-assembly dynamics at nanometer resolution. I substantially advanced this technique and revealed, for the first time, the nanoparticle assembly dynamics such as a layer-by-layer growth process into flat superlattices. This dissertation concludes by highlighting new opportunities from this technical improvement in navigating colloidal interactions to engineer the conformation, phase behaviors and collective dynamics of colloids on the nanometer length scale. The generalized interaction engineering strategy from my research can serve as a general guideline for the design and fabrication of functional colloidal materials from the bottom-up.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2022-05-01The student, Binbin Luo, accepted the attached license on 2020-04-27 at 11:12.The student, Binbin Luo, submitted this Dissertation for approval on 2020-04-27 at 11:34.This Dissertation was approved for publication on 2020-05-04 at 09:49.DSpace SAF Submission Ingestion Package generated from Vireo submission #15080 on 2020-08-25 at 17:41:00Made available in DSpace on 2020-08-27T00:50:03Z (GMT). No. of bitstreams: 5
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Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemOpen Restriction set for Item 115892 on 2021-04-19T17:48:55Z with date null by [email protected] Restriction set for Item 115892 on 2021-04-19T17:49:00Z with date null by [email protected] of I Only Restriction set for Item 115892 on 2021-08-03T16:07:04Z with date 2023-08-03 by [email protected] of I Only Restriction set for Item 115892 on 2021-08-03T16:07:08Z with date 2023-08-03 by [email protected] of the author which was approved by thesis office.U of I Onl
Ji yu yang ben yu guo cheng fang fa de zi ran wen li jian mo yu he cheng
No full textPh.D.Textures synthesis techniques have been extensively studied for decades, which can be widely applied for generating rich appearances of objects in VR and graphics applications. These methods can mainly be divided into two categories: procedural methods and example-based methods. Procedural methods model textures using functions that take pixel positions as variables and with a few tunable parameters. However, the relation between visual appearance and parameters is not intuitive, which makes it hard to tune parameters for desired appearances. Example-based methods model textures directly from real texture exemplars. Even it can generate textures with similar appearance to input ones, intensive computation and large memory usage are required. In this thesis, we study on natural texture modeling and synthesis methods that effectively bridge the procedural and example based methods, to realize efficient processing, compact storage and intuitive texture synthesis.Aggregate textures are well suited for many architectural materials, such as marbles and stones. We study on the synthesis system for aggregate solid textures. Our method generates warping particles and stores them with a few points based on cellular texture. Stereological technique and spring system are used to automatically guide the synthesis procedure. Using adaptive k-means clustering, we can recover color distribution from exemplar with high fidelity. To further discover example information of aggregate texture, we propose two-scale shaping model to automatically and accurately reconstruct 3D particle outlines from 2D-example cross sections. Low frequency spherical harmonics and high frequency ones are used to morph smooth outlines and model particle surface details. Radial basis functions (RBFs) are employed for particle volumetric color representation, and simplified particle proxies are used for efficient particle arrangement. We employ GPU-based rendering pipeline for real-time texture fetching on common graphics cards. Our experiments show that the proposed approaches can generate realistic texturing of solid material with low memory footprint and efficient aggregate-material synthesis in seconds.To facilitate efficient synthesis and intuitive editing of general vector solid texture, we propose the novel solid texture representation, named Radial Basis Function (RBF} solid texture. Such a representation is resolution independent, compact in storage and capable to support efficient random access with an indexing uniform grid. We directly synthesize RBF solid texture from raster exemplar by minimizing an energy function, which encodes the position, color and SDF difference between output volumetric RBF instances and input example planar RBF instances. The minimization process iteratively updates output RBF instances with an EM algorithm. Our experiments show that the proposed algorithm can produce RBF solid textures in high efficiency and compact storage for a variety of exemplars, including stochastic patterns or more structured patterns. Furthermore, RBF solid textures benefit intuitive post-synthesis editing for either region-based and RBF-based effects.Generating natural textures is the great challenging task in graphics and virtual reality, such as variable leaf textures. Unlike other textures, leaves are closely related to its botanic structures, especially veins. Appearing in forms of foliages in the wild, the variety of leaf textures produces the realism of virtual scenes. We propose the novel leaf-texturing method that models the inherent relevance between structural features and pattern distributions. With the structure-guided model, an example-based algorithm is developed to extract and generate leaf textures depending on venation structures. Global variations and local details are processed separately for multi-scale texture features. Our experiments show that our model produces visually plausible leaf textures with variations, which can be easily applied to other applications, such as texture transfer between different leaf structures, aging effect and texture editing. In the future work, we will conduct study on general structure models for various textures, e.g. terrain and urban layout, and interactive texture design. Moreover, we would like to introduce new geometric elements for complex solid texture representation for more compactness and generality.在和圖形應用中紋理合成技術被廣泛用於生成物體的豐富外觀，因而在過去的幾十年中被大量研究。這些方法可以大致分為兩類，即過程紋理方法和基於樣本的方法。過程方法使用函數對紋理進行建模，這些函數的輸入參數包含像素的位置以及少量可調控的參數。過程方法由於這種簡潔的表達，對存儲和運算都非常高效。然而，紋理的視覺表象和過程方法的的參數之間並沒有直觀的聯繫，這使得通過調節參數獲取特定的紋理異常困難。基於樣本的方法直接通過真實紋理樣本進行建模。儘管通過這種途徑能夠生成特定的紋理，但是通常具有運算盤大並且存儲需要高的缺點。在論文中，我們聯合過程方法和基於樣本的方法對自然紋理進行建模，以實現高效的處理，緊湊的存儲以及直觀的紋理合成算法。聚合紋理可用於於多種建築材料的表達， 比如大理石和石塊，我們對聚合體紋理合成算法進行了研究。算法基於蜂窩紋理提出使用少量的點生成翹曲顆粒。體視覺技術和彈簧系統被用於自動引導紋理合成過程。通過使用自適應的K均值聚類， 算法從樣本中重建出高逼真的顏色分佈。為了進一步挖掘聚合紋理的樣本信息， 我們提出一種雙尺度用於自動並且準確得從二維顆粒截面重建三維顆粒模型。低頻球面諧函數被用於構建平滑的三維顆粒輪廓，同時高頻球面諧函數被用於表達三維顆粒表面的細節信息。算法使用徑向基函數表達顆粒內部顏色信息并通過使用簡化的顆粒代理進行高效的顆粒擺放。我們引入了基於GPU的渲染管線， 以實現在一般圖形芯片上的實時紋理拾取。實驗表明文章提出的方法能夠具有真實感的體紋理，並且具有低存儲代價和高合成效率的優點。為了促進一般化體紋理的合成和後編輯， 我們提出一種新穎的體紋理表達，命名為徑向基函數體紋理。這種表達具有分辨率無關，存儲緊湊的優點， 並且結合規則網絡加速， 能夠進行高效隨機紋理拾取。基於這種表達， 我們提出對RBF實例的屬性稽建能量函數， 然後通過最小化能量商數， 直接從二維光柵紋理合成矢量體紋理的算法。這個能量函數衡量了二維樣本中RBF實例的分佈和目標體紋理中RBF實例的差距。EM算法被用於迭代優化能量函數。實驗表明文章提出的算法能夠高效地生成具有隨機樣式和具有更加規則的樣式的體紋理，並且我們提出針對RBF體紋理的直觀的合成后編輯功能，其中包含基於區域信息的編輯和RBF實例的編輯。不同於其他紋理，樹葉紋理和其植物結構緊密相關，主要是葉脈。樹葉一般以簇叢的形式出現，其紋理的多樣化嚴重影響包含植物的場景的真實感。我們提出一種新穎的樹葉紋理著色算法， 這種算法對結構特征和紋理樣式分佈的內在關聯性進行建樣。針對結構引導的紋理模型， 我們提出基於樣本的方法用於提取和生成依賴於葉脈結構的樹葉紋理。算法分別處理全局變化和局部細節， 以保持多尺度下的紋理特征。實驗表明文章提出的模型能夠生成豐富而真實的紋理變化， 並且能夠應用與多種應用， 例如不同樹葉結構的紋理遷移， 樹葉老化以及紋理編輯。在進一步工作中， 我們會對適用于多種自然紋理， 比如地形和城市佈局的一般化結構模型以及交互式紋理設計進行研究。除此之外， 我們希望引入新的幾何元絮素用於表達複雜的體紋理， 以獲取更加緊湊的表達和更強的普適性。Qian, Yinling.Thesis Ph.D. Chinese University of Hong Kong 2018.Includes bibliographical references (leaves 127-137).Abstracts also in Chinese.Title from PDF title page (viewed on …).Qian, Yinling
Erratum: Corrigendum to “Automated quality assessment of precast concrete elements with geometry irregularities using terrestrial laser scanning” (Automation in Construction (2016) 68 (170–182)(S0926580516300541)(10.1016/j.autcon.2016.03.014))
No full textThe authors regret an error in the authorship in the above manuscript. The correct authors and their affiliations are shown as follows. Qian Wanga,b, Min-Koo Kimc, Seongheum Yoonb, Jack C.P. Chenga, Hoon Sohnb,⁎ aDepartment of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong bDepartment of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, Daejeon, South Korea cDepartment of Engineering, University of Cambridge, Cambridge, United Kingdom ⁎Corresponding author. The authors would like to apologise for any inconvenience caused.</p
Fo jiao yu Bei Wei Luoyang de cheng shi bian qian
No full text本文著力於研究北魏都洛四十年間，其城市面貌因受佛教擴張的影響而出現的歷史變遷情況。在微觀視角上，本文亦就佛寺布局形態及其內部寺塔形制的變遷過程，里坊規劃與佛寺布局的相互關係等问题，進行探討。文章關注並探索具體時空中人們的社會生活與佛教信仰間的互動與交融情況，以期能在文獻與實物資料之基礎上，呈現彼時都城居民的日常信仰生活。This dissertation attempts to research the historical changes in the appearance of Luoyang City caused by the expansion of Buddhism during the 40-year period in which it was the capital of the Northern Wei Dynasty. This paper also studies the changing layout of the Buddhist monasteries in Luoyang from a microcosmic perspective, as well as the changing styles of temples in these monasteries. The interrelationship between the design of city blocks and the layout of monasteries were discussed in this paper as well. The interaction and blend of people’s social life and Buddhist Beliefs in such a specific city and period of time were explored. Readers are presented with insights into the daily religious life, based on the historical documents and the archaeological materials.Detailed summary in vernacular field only.周胤.Thesis (Ph.D.) Chinese University of Hong Kong, 2014.Includes bibliographical references (leaves 170-193).Abstracts also in English.Zhou Yin
Electron dynamics in slowly varying antiferromagnetic texture
No full textAdiabatic dynamics of conduction electrons in antiferromagnetic (AFM) materials with slowly varying spin texture is developed. Quite different from the ferromagnetic (FM) case, adiabaticity in AFM texture does not imply perfect alignment of conduction electron spins with background profile, instead, it introduces an internal dynamics between degenerate bands. As a result, the orbital motion of conduction electrons becomes spin dependent and is affected by two emergent gauge fields: one of them is the non-Abelian version of what has been discovered in FM systems; the other leads to an anomalous velocity that has no FM counterpart. Two examples with experimental predictions are provided. DOI: 10.1103/PhysRevB.86.245118Physics, Condensed MatterSCI(E)15ARTICLE24null8
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