Sumitomo Bakelite (Japan)

Polycarbonate (PC) is widely used in impact-resistant transparent components due to its excellent toughness and optical properties. However, its mechanical behavior under high strain rate loading remains insufficiently understood, particularly from a microstructural perspective. In this study, the macro-micro deformation mechanisms of PC under high strain rate compression were systematically investigated through an integrated approach combining multiscale simulations and microstructural characterization. Two PC grades with different molecular weights were subjected to dynamic compression experiments using a split Hopkinson pressure bar at high strain rates (4500, 5500, and 7000 s–1) and temperatures of 233, 296, and 353 K. The results reveal pronounced strain rate and temperature dependence in yield stress, yield strain, strain hardening, and unloading strain. Two-dimensional wide-angle X-ray diffraction and polarized Fourier-transform infrared analyzes demonstrate that molecular chain orientation is significantly enhanced under high strain rate loading, with lower molecular weight PC exhibiting more pronounced strain hardening due to easier chain alignment. Molecular dynamics simulations further elucidate that higher molecular weight PC possesses greater conformational stability and resistance to compression. Additionally, the DSGZ model parameters of different PC was calibrated, and accurately predicting the high strain rate compressive response in finite element simulations. The findings provide deep insights into the microstructural origins of the macroscopic mechanical behavior of PC under high-strain-rate compression, offering valuable guidance for material design and engineering applications.

Jaminan Kesehatan Nasional (JKN) merupakan program strategis pemerintah Indonesia dalam mewujudkan sistem jaminan kesehatan yang menyeluruh bagi seluruh masyarakat. Diluncurkan sejak tahun 2014 dan dikelola oleh Badan Penyelenggara Jaminan Sosial (BPJS) Kesehatan, JKN bertujuan untuk memberikan akses pelayanan kesehatan yang adil, merata, dan terjangkau. Program ini mencakup berbagai layanan kesehatan mulai dari promotif, preventif, kuratif, hingga rehabilitatif. Meskipun telah mencakup lebih dari 80% populasi Indonesia, tantangan masih muncul dalam aspek pembiayaan, kepatuhan peserta, kualitas pelayanan, dan pemerataan akses di daerah terpencil. Dengan terus dilakukan perbaikan sistem dan sosialisasi kepada masyarakat, JKN diharapkan mampu menjadi fondasi utama dalam mewujudkan Universal Health Coverage (UHC) di Indonesia. Pengabdian ini menggunakan metode kuantitatif dengan pendekatan deskriptif. Data yang dikumpulkan terdiri atas data primer dan sekunder. Sasaran pengabdian ini adalah kepala keluarga di Dusun Kelapa sebanyak 75 KK.. adapun hasil kegiatan Pengabdian ini adalah meningkatnya pengetahuan masyarakat melalui penyuluhan, bertambahnya peserta JKN melalui pendampingan pendaftaran kepesertaan, memberikan pemahaman baru kepada masyarakat mengenai kemudahan mengakses layanan JKN secara mandiri. Banyak peserta yang sebelumnya belum mengenal aplikasi ini kini mampu menggunakannya untuk keperluan administrasi kepesertaan. Keberhasilan kegiatan ini menunjukkan bahwa pendekatan edukatif dan partisipatif sangat efektif dalam mendorong kesadaran serta keterlibatan masyarakat terhadap program jaminan sosial nasional.

In this paper, we report low Df and negative tone type photosensitive materials with good film properties for 5G and beyond. The combination of polyimide and cyclo olefin polymer, which we have developed, achieves both excellent film properties and low Df. The less polar crosslinking groups are effective for 365 nm photosensitivity at low Df. The developed material including polyimide also showed satisfactory film properties even after biased HAST (high acceleration stress test). Finally, via patterning of 5 µm, reliable film properties and Df of 0.005 (10 GHz) were realized. This means that our material is the most promising candidate as reliable redistribution layer for next-generation semiconductor packaging.

高分子材では，発生した局所的な変形（くびれ）が試験片平行部を伝播する挙動がしばしば観察される．このような挙動が生じるためには，くびれが伝播した部分が加工硬化している必要がある．しかし，先行研究1)では，くびれの伝播挙動が生じるPC材において，伝播部の軟化が確認された．本研究では，PC材同様にくびれの伝播挙動が確認されている2)PP材を新たに追加し，精密万能試験機AUTOGRAPH AGS-H 5kN（島津製作所製）を使用し，平板型の試験片で準静的引張試験を行った．その際，試験片の板幅面及び板厚面の変形画像を撮影し，デジタル画像相関法を用いて縦ひずみ及び横ひずみを計測した．結果として，PC材と同様に発生したくびれが試験片平行部を伝播する様子が確認された．また，くびれの伝播に伴う試験体の強度変化を把握するためにビッカース硬さ試験を実施した．結果として，PC材と同様にくびれの伝播部の軟化が確認された．PC材，PP材共にくびれの伝播に伴い伝播部が軟化する結果となったが，これはくびれの伝播条件に矛盾する．その原因として①硬さの異方性，②再降伏の早期化，が考えられた．①材料の異方性により断面では硬化している可能性が考えられたが，断面と表面の硬さに差がなく，断面においても伝播部の軟化が確認されたため，伝播部の軟化原因は材料の異方性によるものではないことが分かった．②同一試験片に対して複数回の引張試験を実施したところ，初回負荷時に比べ2回目以降の負荷では，低い応力で再降伏することが確認された．そのため，硬さ試験ではこの低い応力での再降伏点が反映され軟化につながっていると考えられる．

We demonstrate 100 Gbps PAM4 VCSEL-based transmission over 12-channel connectorized meter-scale flexible multimode polymer waveguides with a bandwidth-length product greater than 56 GHz·m at a wavelength of 850 nm for board-level optical interconnects application.

Background: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak has had a significant impact on public health and the global economy. Several diagnostic tools are available for the detection of infectious diseases, with reverse transcription-polymerase chain reaction (RT-PCR) testing specifically recommended for viral RNA detection. However, this diagnostic method is costly, complex, and time-consuming. Although it does not have sufficient sensitivity, antigen detection by an immunoassay is an inexpensive and simpler alternative to RT-PCR. Here, we developed an ultrahigh sensitivity digital immunoassay (d-IA) for detecting SARS-CoV-2 nucleocapsid (N) protein as antigens using a fully automated desktop analyzer based on a digital enzyme-linked immunosorbent assay. Methods: We developed a fully automated d-IA desktop analyzer and measured the viral N protein as an antigen in nasopharyngeal (NP) swabs from patients with coronavirus disease. We studied nasopharyngeal swabs of 159 and 88 patients who were RT-PCR-negative and RT-PCR-positive, respectively. Results: The limit of detection of SARS-CoV-2 d-IA was 0.0043 pg/mL of N protein. The cutoff value was 0.029 pg/mL, with a negative RT-PCR distribution. The sensitivity of RT-PCR-positive specimens was estimated to be 94.3% (83/88). The assay time was 28 min. Conclusions: Our d-IA system, which includes a novel fully automated desktop analyzer, enabled detection of the SARS-CoV-2 N-protein with a comparable sensitivity to RT-PCR within 30 min. Thus, d-IA shows potential for SARS-CoV-2 detection across multiple diagnostic centers including small clinics, hospitals, airport quarantines, and clinical laboratories.

It is a well-known fact that there is significant difference in magnitude of flow stresses and work hardening rates of polymeric materials between in tension and compression. There is a possibility that hydrostatic pressure is involved in this asymmetry to the loading axis, in which case volume change occurs in plastic deformation. And also, the propagation of localized deformations is often observed as a deformation behavior of polymeric materials. In such cases, it has been confirmed that the propagating portion of the crack must be hardened, but the deformed portion is softened. The aim of this study is to measure the variation of plastic Poisson’s ratio by means of Digital Image Correlation method to clarify the existence of the plastic compressibility of Naylon66 and Polycarbonate. Another aim is to elucidate the mechanism of softening at the neck. The authors conducted tensile tests of thin strip specimens and measured the axial and lateral strains by DIC method, then, plastic Poisson's ratio was derived. The result showed that plastic Poisson’s ratio of Naylon66 and Polycarbonate was smaller than the value of 0.5, that result in the existence of plastic compressibility in these materials. The Micro-Vickers hardness measurement for a gauge length was also performed to clarify the strength distribution of a specimen, and the results showed that the necking part of the materials was softened.

The structural formation mechanism of phenolic resin-silica interfaces was investigated in situ by neutron reflectometry during curing. There was a 4 nm thick novolac resin adsorption layer on the silica surface before curing. The curing reaction of the novolac resin with hexamethylenetetramine (HMTA) increased the coherent neutron scattering length density of the resin due to the cure shrinkage accompanied by the volatilization of ammonia, which is a byproduct of HMTA decomposition. As curing proceeded at 180 °C, the thickness of the bulk layer increased despite the cure shrinkage, and the thickness of the interfacial layer decreased from 4 to 1 nm. This is attributed to the diffusion of decomposed HMTA fragments generated in the bulk layer into the interfacial novolac adsorption layer during diffusion throughout the bulk layer, incorporating the upper part of the interfacial layer reacting with the fragment into the bulk layer. On the other hand, the fragments could not diffuse into the tightly bound immobile segments of novolac resin in direct contact with the silica surface, retaining the 1-2 nm thick interfacial layer in the cured resin. This structural formation mechanism caused interfacial cross-link inhomogeneity in the cured resin on the silica surface.