Browsing by Author "Sun, Hao-Jan"

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A Non-Linear Iterative Method for Multi-Layer DOT Sub-Surface Imaging System
(2014-01-01)
Hou, Hsiang-Wen
;
Wu, Shih-Yang
;
Sun, Hao-Jan
;
Fang, Wai-Chi
;
分子醫學與生物工程研究所
Diffuse Optical Tomography (DOT) has become an emerging non-invasive technology, and has been widely used in clinical diagnosis. Functional near-infrared (FNIR) is one of the important applications of DOT. However, FNIR is used to reconstruct two-dimensional (2D) images for the sake of good spatial and temporal resolution. In this paper we propose a multiple-input and multiple-output (MIMO) based data extraction algorithm method in order to increase the spatial and temporal resolution. The non-linear iterative method is used to reconstruct better resolution images layer by layer. In terms of theory, the simulation results and original images are nearly identical. The proposed reconstruction method performs good spatial resolution, and has a depth resolutions capacity of three layers.
A Supramolecular "Double-Cable" Structure with a 129(44) Helix in a Columnar Porphyrin-C-60 Dyad and its Application in Polymer Solar Cells
(2012-11-01)
Wang, Chien-Lung
;
Zhang, Wen-Bin
;
Sun, Hao-Jan
;
Van Horn, Ryan M.
;
Kulkarni, Rahul R.
A novel porphyrin-C-60 dyad (PCD1) is designed and synthesized to investigate and manipulate the supramolecular structure where geometrically isotropic [such as [60]fullerene (C-60)] and anisotropic [such as porphyrin (Por)] units coexist. It is observed that PCD1 possesses an enantiomeric phase behavior. The melting temperature of the stable PCD1 thermotropic phase is 160 degrees C with a latent heat (Delta H) of 18.5 kJ mol(-1). The phase formation is majorly driven by the cooperative intermolecular PorPor and C60C60 interactions. Structural analysis reveals that this stable phase possesses a supramolecular double-cable structure with one p-type Por core columnar channel and three helical n-type C-60 peripheral channels. These double-cable columns further pack into a hexagonal lattice with a = b = 4.65 nm, c = 41.3 nm, alpha = beta = 90 degrees and gamma = 120 degrees. The column repeat unit is determined to possess a 129(44) helix. With both donor (D; Pro) and acceptor (A; C-60) units having their own connecting channels as well as the large D/A interface within the supramoleculassr double-cable structure, PCD1 has photogenerated carriers with longer lifetimes compared to the conventional electron acceptor [6,6]-phenyl-C-61-butyric acid methyl ester. A phase-separated columnar morphology is observed in a bulk-heterojunction (BHJ) material made by the physical blend of a low band-gap conjugated polymer, [poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta [2,1-b;3,4-b']-dithiophene)-alt-4,7-(2,1,3-benzothia-diazole)] (PCPDTBT), and PCD1. With a specific phase structure in the solid state and in the blend, PCD1 is shown to be a promising candidate as a new electron acceptor in high performance BHJ polymer solar cells.
An Improved Diffuse Optical Tomography Image Reconstruction Based on Sparse Recovery Method
(2016)
Sun, Hao-Jan
;
Fang, Wai-Chi
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Diffuse Optical Tomography (DOT) is a non-invasive image detecting technique. It is used to assess spatial variation with absorption and scattering coefficients for tumor detection, distribution of oxygen concentration analysis, oxygenated hemoglobin concentration measurement or deoxygenated hemoglobin concentration measurement. In this paper, we use sparse recovery methods for DOT image reconstruction. Using the non-linear iterative method to reconstruct the DOT image can increase the resolution of each reconstructed layer. Sparse recovery methods use the p-norm in the evaluation question in 0 < p <= 1. When the amount of independent gauge is limited by normal, which is a basic example for diffuse optical tomographic image reconstruction, sparse recovery methods present good performance.
Complex Columnar Hexagonal Polymorphism in Supramolecular Assemblies of a Semifluorinated Electron-Accepting Naphthalene Bisimide
(2015-01-21)
Wu, Yu-Chun
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Leowanawat, Pawaret
;
Sun, Hao-Jan
;
Partridge, Benjamin E.
;
Peterca, Mihai
Simple synthetic methods for a strongly electron-accepting naphthalene bisimide (NBI) derivative functionalized with a new environmentally friendly chiral racemic semifluorinated alkyl group and with AB(3) minidendrons containing the same semifluorinated group are reported. The semifluorinated dendron was attached to the imide groups of the NBI via one, two, and three (m = 1, 2, 3) methylenic units. The NBI-containing semifluorinated groups and the dendronized NBI with m = 1 and 2 self-organize into lamellar crystals. The dendronized NBI with m = 3 self-assembles into an unprecedentedly complex and ordered column that self-organizes in a columnar hexagonal periodic array. This array undergoes a continuous transition to a columnar hexagonal superlattice that does not display a first-order phase transition during analysis by differential scanning calorimetry at heating and cooling rates of 10 and 1 degrees C/min. These complex columnar hexagonal periodic arrays with intramolecular order could be elucidated only by a combination of powder and fiber X-ray diffraction studies and solid-state NMR experiments. The lamellar crystals self-organized from m = 1 and the two highly ordered columnar hexagonal periodic arrays of m = 3 are assembled via thermodynamically controlled processes. Since strongly electron-accepting derivatives are of great interest to replace fullerene acceptors in organic photovoltaics and for other supramolecular electronic materials, the multitechnique structural analysis methodology elaborated here must be taken into consideration in all related studies.
Crystal structure and molecular packing of an asymmetric giant amphiphile constructed by one C-60 and two POSSs
(2014-08-18)
Lin, Ming-Champ
;
Hsu, Chih-Hao
;
Sun, Hao-Jan
;
Wang, Chien-Lung
;
Zhang, Wen-Bin
Based on our recent understanding and development of functionalized molecular nanoparticles (MNPs) as building blocks for constructing various giant molecules, we report our efforts on design and synthesis of an asymmetric giant amphiphile, diBPOSS-C-60, composed of one [60]fullerene (C-60) covalently linked with two isobutyl-functionalized polyhedral oligomeric silsesquioxane (BPOSS) MNPs. Its crystal structure and molecular packing were investigated. The compositional asymmetry between C-60 and BPOSS led to a "sandwich-layered" molecular packing scheme, where a single layer of C-60 is sandwiched between double BPOSS layers: a so-called "one-and-half-layered" structure. Within these layers, the molecules further organized into crystalline arrays. Interestingly, this compound can be viewed as size amplification of a class of atomically thin, two-dimensional layered transition metal dichalcogenides with the "one-and-half-layered" structure. 2014 Elsevier Ltd. All rights reserved.
Crystal structure and molecular packing of an asymmetric giant amphiphile constructed by one C-60 and two POSSs
(2014-08-18)
Lin, Ming-Champ
;
Hsu, Chih-Hao
;
Sun, Hao-Jan
;
Wang, Chien-Lung
;
Zhang, Wen-Bin
Based on our recent understanding and development of functionalized molecular nanoparticles (MNPs) as building blocks for constructing various giant molecules, we report our efforts on design and synthesis of an asymmetric giant amphiphile, diBPOSS-C-60, composed of one [60]fullerene (C-60) covalently linked with two isobutyl-functionalized polyhedral oligomeric silsesquioxane (BPOSS) MNPs. Its crystal structure and molecular packing were investigated. The compositional asymmetry between C-60 and BPOSS led to a "sandwich-layered" molecular packing scheme, where a single layer of C-60 is sandwiched between double BPOSS layers: a so-called "one-and-half-layered" structure. Within these layers, the molecules further organized into crystalline arrays. Interestingly, this compound can be viewed as size amplification of a class of atomically thin, two-dimensional layered transition metal dichalcogenides with the "one-and-half-layered" structure. 2014 Elsevier Ltd. All rights reserved.
Diffuse Optical Tomography Image Reconstruction Based on Sparse Recovery Methods
(2015-01-01)
Sun, Hao-Jan
;
Hou, Hsiang-Wen
;
Chou, Chia-Ching
;
Fang, Wai-Chi
;
電機工程學系
Diffuse Optical Tomography ( DOT) is a non-invasive image detecting technique. It is used to assess spatial variation with absorption and scattering coefficients for tumor detection, distribution of oxygen concentration analysis, oxygenated hemoglobin concentration measurement or deoxygenated hemoglobin concentration measurement. In this paper, we use sparse recovery methods for DOT image reconstruction. Using the non-linear iterative method to reconstruct the DOT image can increase the resolution of each reconstructed layer. Sparse recovery methods use the p-norm regularization in the estimation problem with 0 < p <= 1. When the number of independent measurements is limited by nature, which is a typical case for diffuse optical tomographic image reconstruction, sparse recovery methods present good performance. According to the simulation results the reconstruction algorithm can parse the tumor clearly with p=0.6. The projection errors are 0.45357, 0.44588, 0.46781, 0.44109, and 0.47174( tumor / background) in each tumor position case using p=0.6. Since that the projection errors with p=0.6 are smaller than projection errors using p=1 or p=2, p=0.6 is selected to be the reconstructed parameter to have the best reconstructed results for the same iteration numbers. Simulation results show that the sparse recovery methods are good to improve the reconstructed image quality.
Phase behaviour and Janus hierarchical supramolecular structures based on asymmetric tapered bisamide
(2012)
Sun, Hao-Jan
;
Wang, Chien-Lung
;
Hsieh, I-Fan
;
Hsu, Chih-Hao
;
Van Horn, Ryan M.
A precisely defined molecular Janus compound based on asymmetric tapered 1,4-bis[3,4,5-tris(alkan-1-yloxy) benzamido] benzene bisamide (abbreviated as C(22)PhBAEO(3)) was designed and synthesized, and its phase behavior was fully investigated. The C(22)PhBAEO(3) compound possesses a rigid core with three aromatic rings connected with amide bonds which possess the ability to form hydrogen (H) bonds. Three hydrophobic alkyl flexible tails and three hydrophilic flexible methyl terminated triethylene glycol tails are located at the other end. Major phase transitions and their origins in C(22)PhBAEO(3) were studied via DSC and 1D WAXD techniques. Its hierarchical supramolecular crystal structure was further identified through combined techniques of 2D WAXD and SAXS as well as SAED. Results based on computer simulations confirmed the structure determination. It was found that the C(22)PhBAEO(3) possesses three phases through various thermal treatments including a micro-phase separated columnar liquid crystal (col.) phase, a metastable crystal I phase and a stable crystal II phase. Among them, the crystal II phase showed that the columnar structure possesses 3D inter-column order and highly crystalline alkyl tails with a long-range overall orientational order. Four C(22)PhBAEO(3) molecules self-assembled into a phase-separated disc with an ellipsoidal shape having a C-2 symmetry along the disc normal. These discs then stacked on top of each other to generate a 1D asymmetric column through H-bonding, and further packed into a 3D long-range ordered monoclinic lattice. The unit cell parameters of this lattice were determined to be a = 5.08 nm, b = 2.41 nm, c = 0.98 nm, alpha = 90 degrees, beta = 90 degrees, and gamma = 70.5 degrees. The alkyl chain tails crystallize within the hydrophobic layers and possess a relatively fixed orientation with respect to the column packing due to the selective interactions based on the hydrophobic/hydrophilic microphase separation. Both phase behaviour and unit cell structure showed significant difference compared with the symmetrically tapered counterparts. The results provided a new approach of fine-tuning not only in the Janus supramolecular structures but also in the formation pathway of the self-assembling process in order to meet the specific requirements for optical and biological applications.
Screening Libraries of Semifluorinated Arylene Bisimides to Discover and Predict Thermodynamically Controlled Helical Crystallization
(2016-12)
Ho, Ming-Shou
;
Partridge, Benjamin E.
;
Sun, Hao-Jan
;
Sahoo, Dipankar
;
Leowanawat, Pawaret
Synthesis, structural, and retrostructural analysis of a library containing 16 self-assembling perylene (PBI), 1,6,7,12-tetrachloroperylene (Cl4PBI), naphthalene (NBI), and pyromellitic (PMBI) bisimides functionalized with environmentally friendly AB(3) chiral racemic semifluorinated minidendrons at their imide groups via m = 0, 1, 2, and 3 methylene units is reported. These semifluorinated compounds melt at lower temperatures than homologous hydrogenated compounds, permitting screening of all their thermotropic phases via structural analysis to discover thermodynamically controlled helical crystallization from propeller-like, cogwheel, and tilted molecules as well as lamellar-like structures. Thermodynamically controlled helical crystallization was discovered for propeller-like PBI, Cl4PBI and NBI with m = 0. Unexpectedly, assemblies of twisted Cl(4)PBIs exhibit higher order than those of planar PBIs. PBI with m = 1, 2, and 3 form a thermodynamically controlled columnar hexagonal 2D lattice of tilted helical columns with intracolumnar order. PBI and Cl4PBI with m = 1 crystallize via a recently discovered helical cogwheel mechanism, while NBI and PMBI with m = 1 form tilted helical columns. PBI, NBI and PMBI with m = 2 generate lamellar-like structures. 3D and 2D assemblies of PBI with m = 1, 2, and 3, NBI with m = 1 and PMBI with m = 2 exhibit 3.4 angstrom pi-pi stacking. The library approach applied here and in previous work enabled the discovery of six assemblies which self-organize via thermodynamic control into 3D and 2D periodic arrays, and provides molecular principles to predict the supramolecular structure of electronically active components.