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Monolayer materials can be vertically stacked into artificial solids, known as the van der Waals heterostructures (vd-WHs) [1], to realize a new class of ultrathin optoelectronic, electronic, and quantum devices, which have significant potential to revolutionize the field of nanoelectronics and impact a wide range of application areas including transparent displays, sensor arrays, and logic and memory circuits. However, today’s assembly of vdWH devices is still primarily through manual manipulation, which lacks the precision and repeatability needed for the scalable manufacturing of wafer-scale vdWH device arrays outside a research setting. Aiming to enable the automated, scalable, and repeatable manufacturing of vdWH device arrays, this paper presents the design, prototyping, and preliminary tests of a novel semi-automated soft-robotic stamp transfer system for thin-film materials. The system uses a dry elastomer stamp with its adhesion controlled by temperature and peeling speed for material transfer. A combination of electromagnetic and pneumatic actuation is used for the soft-robotic stamp to realize a gentle and uniform pressing of the stamp over the material. An optical microscope, force sensors, and temperature sensors are integrated to enable instrumentation of the transfer process. Preliminary experiments were conducted using our system to conduct for exfoliated graphite transfer. Test results demonstrate the reliable and repeatable transfer of 2D crystal flakes, which show promise to enable the deterministic and scalable assembly of vdWH-based device arrays at wafer scale. 

Large rivers are the main arteries for transportation of carbon to the ocean; yet, how hydrology and anthropogenic disturbances may change the composition and export of dissolved organic matter along large river continuums is largely unknown. The Yangtze River has a watershed area of 1.80 × 10⁶ km². It originates from the Qinghai‐Tibet Plateau and flows 6300 km eastward through the center of China. We collected samples (n= 271) along the river continuum and analyzed weekly samples at the most downstream situated gauging station in 2017–2018 and gathered long‐term (2006–2018) water quality data. We found higher gross domestic product, population density, and urban and agricultural land use downstream than upstream of the Three Gorges Dam, coinciding with higher dissolved organic carbon (DOC), UV absorption (a₂₅₄), specific ultraviolet absorbance (SUVA₂₅₄), parallel factor analysis‐derived C1–C5, aliphatic compounds, and lowera₂₅₀:a₃₆₅and spectral slope (S_275–295). Chemical oxygen demand, humic‐like C1–C2 and C6, and protein‐like C4 and C7 increased, while dissolved oxygen and ammonium decreased with increasing discharge at most of the sites studied, including the intensively monitored downstream site. The annual DOC fluxes were ca. 1.5–1.8 Tg yr⁻¹, and 12–18% was biodegradable in a 28‐d bio‐incubation. Our results highlight that urbanization and stormwater periods enhanced the export of both terrestrial organic‐rich substances and household effluents from nearshore residential areas. Our study emphasizes the continued need to protect the Yangtze River watershed as increased organic carbon loading or altered composition and bio‐lability may change the ecosystem function and carbon cycling.