Xiang Li

The LUnar soil Water molecular Analyzer (LUWA) is a payload aboard China's Chang'E-7 mission (to be launched in 2026), which will conduct first in-situ detection of water ice and volatiles within the permanently shadowed regions (PSRs) at the lunar south pole. As the cornerstone of the fourth phase of the Chinese Lunar Exploration Program, Chang'E-7 employs a novel multi-probe architecture of an orbiter, lander, rover, and mini-flying probe to explore the rim of Shackleton crater.Mount on the mini-flying probe, LUWA will analyze volatile components in the lunar soil extracted from both the sunlit area and PSRs. Its primary objectives include: (1) verifying the presence of water molecular and determining its abundance in the lunar regolith, (2) performing elemental and isotopic analyses (e.g., D/H) to determine the origin of lunar volatiles, and (3) investigating distribution, and evolution of water ice in the PSRs.

Remote sensing has identified water-ice in the Moon’s polar regions; however, it cannot directly verify the existence and origin of lunar water in the permanently shadowed regions. The LUnar soil Water molecular Analyzer (LUWA) is a key payload on the mini-flying probe of China’s forthcoming Chang’E-7 mission, scheduled for launch in 2026. The mission aims to perform the first in-situ detection of water ice and volatiles of the lunar south pole. LUWA comprises a tunable laser spectrometer (TLS) for in situ analysis of H₂O and HDO, as well as a time-of-flight mass spectrometer (TOF-MS) for the analysis of gas molecules with mass numbers under 200 amu, including H₂O, CO2 and CH₄. A differential absorption spectrometer (DAS) will be mounted on the leg of the probe to pre-detect the existence of water-ice and monitor its content during drilling. Ground testing demonstrates LUWA’s capability to detect water ice at concentrations as low as 0.01 wt% in evolved gas analysis mode and ≥0.5 wt% through DAS, with water content quantification achievable within the 0.1–4.5 wt% range and δD precision of ±50‰. Key challenges include correcting sublimation losses, adsorption effects, and isotopic fractionation during sample handling. LUWA will provide critical data on the abundance, origin, and distribution of lunar water, supporting future in-situ resource utilization and enhancing our comprehension of volatile dynamics on the Moon.

月球极区水冰探测对揭示月球演化、支撑未来月球科研站建设至关重要. 然而, 通过现有遥感手段与返回样品难以精确获取其赋存形态、含量及来源. 嫦娥七号( Chang’E-7 )飞跃器将搭载月壤水分子分析仪(LUWA), 首次对月球南极永久阴影区水冰开展就位探测. 本文介绍了LUWA的组成、原理及其与水冰钻取装置协同实现“钻探采样－接样密封－加热分析”的探测过程. 为确保载荷在轨实现高灵敏度、宽动态范围的水冰含量探测和高精度水同位素分析, 针对三个测水功能模块搭建了地面定标试验装置, 提出了定标方法; 围绕整机性能指标, 搭建了月壤水冰就位探测模拟试验平台, 模拟极区水冰的钻采、接样、密封、加热与分析全过程, 为在轨月壤水冰含量等数据反演提供重要支撑.

Distinguishing the origin of lunar water ice requires in situ isotopic measurements with high sensitivity and robustness under extreme lunar conditions; however, challenges such as uncertain water contents and isotopic fractionation induced by regolith particles restrict isotopic analysis. Herein, we present a miniaturized tunable diode laser absorption spectrometer (TDLAS) developed as the core prototype for the Chang'E-7 Lunar Soil Water Molecule Analyzer (LSWMA). The wavelength range of the instrument is 3659.5-3662.0 cm^-1, and the system integrates a Herriott cell for stable multi-isotope (H₂¹⁶O, H₂¹⁸O, H₂¹⁷O, and HD¹⁶O) detection and employs regolith samples of known isotopic experiments to quantify adsorption-induced fractionation. Performance evaluations demonstrated a dynamic water detection range of 0.01-2 wt % and isotope precision up to 1.3‰ for δD (30.5 s), 0.77‰ for δ¹⁸O (36 s), and 0.75‰ for δ¹⁷O (21.5 s) with extended averaging. Repeated injections of three types of standard water revealed a volume-dependent deviation (ΔδD up to -59.5‰) attributed to multilayer adsorption effects, while simulated lunar soil experiments identified additional isotopic fractionation (ΔδD up to -12.8‰) caused by particle binding. These results validate the ability of the spectrometer to resolve subtle isotopic shifts under lunar conditions, providing critical data for distinguishing water origins and advancing future resource utilization strategies.

We report here the development of a compact, open-path CO₂ and H₂O sensor based on the newly introduced scanned-wavelength modulation spectroscopy with the first harmonic phase angle (scanned-WMS-θ1f) method for high-sensitivity, high temporal resolution, ground-based measurements. The considerable advantage of the sensor, compared with existing commercial ones, lies in its fast response of 500 Hz that makes this instrument ideal for resolving details of high-frequency turbulent motion in exceptionally dynamic coastal regions. The good agreement with a commercial nondispersive infrared analyzer supports the utility and accuracy of the sensor. Allan variance analysis shows that the concentration measurement sensitivities can reach 62 ppb CO₂ in 0.06 s and 0.89 ppm H₂O vapor in 0.26 s averaging time. Autonomous field operation for 15-day continuous measurements of greenhouse gases (CO₂/H₂O) was performed on a shore-based monitoring tower in Daya Bay, demonstrating the sensor’s long-term performance. The capability for high-quality fast turbulent atmospheric gas observations allow the potential for better characterization of oceanographic processes.

Robust marine carbon sensors with small size, low power consumption, and high sensitivity provide greater insight into the carbon cycle studies and resolve environmental variability. We report here the development of a diminutively integrated tunable diode laser absorption spectroscopy (TDLAS) system with a specially designed multipass gas cell for small amounts of dissolved gas extractions and measurements. It was used to detect and monitor carbon dioxide (CO₂) dissolved in water and seawater. Systematic experiments have been carried out for system evaluation in the lab. Extracted CO₂ was determined via its 4989.9 cm⁻¹ optical absorption line. The achieved TDLAS measurement precision was 4.18 ppm for CO₂, measured by averaging up to 88 s. The integrated absorbance was found to be linear to gas concentrations over a wide range. Comparison measurements of the atmospheric CO₂ values with a commercial instrument confirmed a good accuracy of our TDLAS-based system. The first test campaign was also accomplished with a hollow fiber membrane contactor, and concentrations of CO₂ were quantitatively detected with partial degasification operations. The results clearly show the ability to continuously measure dissolved gases and highlight the potential of the system to help us better understand physical and geochemical processes in a marine environment.

Trust is the foundation of interpersonal relationship and interaction as in social networks as in real world. Previous researches about the trust between users mainly focus on nonadjacent users in social networks, where the trust between adjacent users is assumed to be known. However, in most social networks, the trust between adjacent users is unknown, that limits the applications of those nonadjacent users trust models. In this paper, we propose an adjacent users trust measurement model(AUTrust) and discuss how to construct a trust social network with AUTrust. The factors affecting trust between users could be classified into three dimensions: (i) similarity between users, (ii) familiarity between users, (iii) users' social reputation. The last two dimensions can be used to reflect asymmetry of trust between users. Then we discuss the methods of quantifying trust with these dimensions. Users' information that AUTrust needs can be collected with API provided by social networks, so the model can be widely applied to social networks. Finally, we evaluated the model on 10-million-level Ten cent Weibo dataset, and the experiment proves the practicability and universality of AUTrust model.