다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

第12次 아시아ㆍ太平洋 矯政局長會議 參加記

Driven by functionality and purity demand for applications of inorganic nanoparticle colloids in optics, biology, and energy, their surface chemistry has become a topic of intensive research interest. Consequently, ligand-free colloids are ideal reference materials for evaluating the effects of surface adsorbates from the initial state for application-oriented nanointegration purposes. After two decades of development, laser synthesis and processing of colloids (LSPC) has emerged as a convenient and scalable technique for the synthesis of ligand-free nanomaterials in sealed environments. In addition to the high-purity surface of LSPC-generated nanoparticles, other strengths of LSPC include its high throughput, convenience for preparing alloys or series of doped nanomaterials, and its continuous operation mode, suitable for downstream processing. Unscreened surface charge of LSPC-synthesized colloids is the key to achieving colloidal stability and high affinity to biomolecules as well as support materials,...

Laser Synthesis and Processing of Colloids: Fundamentals and Applications

One of the most intriguing protein materials found in nature is bone, a material composed of assemblies of tropocollagen molecules and tiny hydroxyapatite mineral crystals that form an extremely tough, yet lightweight, adaptive and multifunctional material. Bone has evolved to provide structural support to organisms, and therefore its mechanical properties are of great physiological relevance. In this article, we review the structure and properties of bone, focusing on mechanical deformation and fracture behavior from the perspective of the multidimensional hierarchical nature of its structure. In fact, bone derives its resistance to fracture with a multitude of deformation and toughening mechanisms at many size scales ranging from the nanoscale structure of its protein molecules to the macroscopic physiological scale.

On the Mechanistic Origins of Toughness in Bone

We introduce optically clear and resilient free-form micro-optical components of pure (non-photosensitized) organic-inorganic SZ2080 material made by femtosecond 3D laser lithography (3DLL). This is advantageous for rapid printing of 3D micro-/nano-optics, including their integration directly onto optical fibers. A systematic study of the fabrication peculiarities and quality of resultant structures is performed. Comparison of microlens resiliency to continuous wave (CW) and femtosecond pulsed exposure is determined. Experimental results prove that pure SZ2080 is ∼20 fold more resistant to high irradiance as compared with standard lithographic material (SU8) and can sustain up to 1.91 GW/cm2 intensity. 3DLL is a promising manufacturing approach for high-intensity micro-optics for emerging ﬁelds in astro-photonics and atto-second pulse generation. Additionally, pyrolysis is employed to homogeneously shrink structures up to 40% by removing organic SZ2080 constituents. This opens a promising route towards downscaling photonic lattices and the creation of mechanically robust glass-ceramic microstructures.

Optically Clear and Resilient Free-Form µ-Optics 3D-Printed via Ultrafast Laser Lithography

3D meso scale structures that can reach up to centimeters in overall size but retain micro- or nano-features, proved to be promising in various science fields ranging from micro-mechanical metamaterials to photonics and bio-medical scaffolds. In this work, we present synchronization of the linear and galvanometric scanners for efficient femtosecond 3D optical printing of objects at the meso-scale (from sub-μm to sub-cm spanning five orders of magnitude). In such configuration, the linear stages provide stitch-free structuring at nearly limitless (up to tens-of-cm) working area, while galvo-scanners allow to achieve translation velocities in the range of mm/s-cm/s without sacrificing nano-scale positioning accuracy and preserving the undistorted shape of the final print. The principle behind this approach is demonstrated, proving its inherent advantages in comparison to separate use of only linear stages or scanners. The printing rate is calculated in terms of voxels/s, showcasing the capability to maintain an optimal feature size while increasing throughput. Full capabilities of this approach are demonstrated by fabricating structures that reach millimeters in size but still retain sub-μm features: scaffolds for cell growth, microlenses, and photonic crystals. All this is combined into a benchmark structure: a meso-butterfly. Provided results show that synchronization of two scan modes is crucial for the end goal of industrial-scale implementation of this technology and makes the laser printing well aligned with similar approaches in nanofabrication by electron and ion beams.

/pdf/mesoscale-laser-3d-printing-4csddzdqtz.pdf

Mesoscale laser 3D printing

https://iopscience.iop.org/article/10.1088/2040-8986/aab3fe/pdf

Optical 3D printing: bridging the gaps in the mesoscale

3D laser lithography of a negative photopolymer (zirconium/silicon hybrid solgel SZ2080) doped with gold nanoparticles (Au NPs) is performed with a 515 nm and 300 fs laser system and the effect of doping is explored. By varying the laser-generated Au NP doping concentration from 4.8 10−6 wt% to 9.8 10−3 wt% we find that the fabricated line widths are enlarged by up to 14.8% compared to structures achieved in pure SZ2080. While implicating a positive effect on the photosensitivity, the doping has no adverse impact on the mechanical quality of intricate 3D microstructures produced from the doped nanocompound. Additionally, we found that SZ2080 increases the long term (~months) colloidal stability of Au NPs in isopropanol. By discussing the nanoparticle–light interaction in the 3D polymer structures we provide implications that our findings might have on other fields, such as biomedicine and photonics.

https://iopscience.iop.org/article/10.1088/0957-4484/27/15/154001/pdf

Plasmon assisted 3D microstructuring of gold nanoparticle-doped polymers.

An approach employing ultrafast laser hybrid subtractive-additive microfabrication, which combines ablation, three-dimensional nanolithography, and welding, is proposed for the realization of a lab-on-chip (LOC) device. A single amplified Yb:KGW femtosecond (fs)-pulsed laser source is shown to be suitable for fabricating microgrooves in glass slabs, polymerization of fine-meshes microfilter out of hybrid organic–inorganic photopolymer SZ2080 inside them, and, finally, sealing the whole chip with cover glass into a single monolithic piece. The created microfluidic device proved its particle sorting function by separating 1- and 10-μm polystyrene spheres in an aqueous mixture. All together, this proves that laser microfabrication based on a single amplified fs laser source is a flexible and versatile approach for the hybrid subtractive-additive manufacturing of functional mesoscale multimaterial LOC devices.

/pdf/hybrid-subtractive-additive-welding-microfabrication-for-lab-3o60w9exu4.pdf

Linas Jonušauskas

Papers

Optically Clear and Resilient Free-Form µ-Optics 3D-Printed via Ultrafast Laser Lithography

Mesoscale laser 3D printing

Optical 3D printing: bridging the gaps in the mesoscale

Plasmon assisted 3D microstructuring of gold nanoparticle-doped polymers.

Hybrid subtractive-additive-welding microfabrication for lab-on-chip applications via single amplified femtosecond laser source