Récentes découvertes à Quanzhou (Zaitun)

Qinzhang Yang, Dasheng Chen, Lombard Denys, Salmon Claudine. Récentes découvertes à Quanzhou (Zaitun). In: Archipel, volume 39, 1990. pp. 81-91

Highly Sensitive and Flexible Copper Oxide/Graphene Non‐Enzymatic Glucose Sensor by Laser Direct Writing

Abstract Accurate and convenient detection of human blood glucose levels is an effective method for early diagnosis of diabetes and prevention of complications. The flexible and wearable electrochemical glucose sensor with low cost, fast responsiveness, good stability, reliability, and high sensitivity has attracted much attention in monitoring glucose concentration. The preparation of a conductive layer with catalytic activity on a flexible substrate is the key to making a wearable glucose sensor. Here, graphene composite materials sintered with copper oxide (CuO) nanoparticles are successfully prepared on a polyimide film by laser direct writing method and fabricated a flexible non‐enzymatic glucose sensor using laser‐engraved graphene (LEG) as a conductive electrode. The CuO/LEG sensor exhibits a high sensitivity of 619.43 μA mm−1 cm−2 in 0–3 mm glucose and 462.96 μA mm−1 cm−2 in 0–8 mm glucose. In addition, the CuO/LEG sensor shows good reproducibility, high anti‐interference capability, and long‐term stability. It also presents good bending stability, which can maintain 82.40% initial current after 100 times bending. Moreover, the CuO/LEG sensor has an obvious step‐ampere response in the detection of sweat samples, indicating the great potential of wearable sweat sensors

Description of steam chamber shape in heavy oil recovery using 4D microgravity measurement technology

4D microgravity measurement is used to study the underground medium, especially underground fluid variation state and process, using repeated measurements of gravity data at different periods. A model of microgravity variation calculation for the Guantao Formation in the Du 84 block of the Liaohe Oilfield was established according to the practical condition of the steam assisted gravity drainage (SAGD) of super heavy oil reservoir. The distribution of residual gravity that reflects the density change of the steam injection layer and heavy oil layer can be obtained using the target area 4D microgravity measured at different periods through wavelet transformation. With −20 μGal as the main anormaly, the variation of steam chamber shape in the steam assisted gravity drainage can be quantitatively described by analyzing the distribution of steam chamber, and drawing the steam chamber overlapping map of two observations. Numerical simulation and well temperature test verified the feasibility of the technology. The result from the technology can be used to adjust steam injection scheme timely according to the morphological changes in the steam chamber, for example, the Gh12 well has got good results, with oil production going up from 65.4 t/d in May 2010 to 82.8 t/d in May 2012 after adjustment of its injection scheme. Key words: gravity field, SAGD, microgravimetry, steam chambe

High-Linearity Hydrogel-Based Capacitive Sensor Based on Con A–Sugar Affinity and Low-Melting-Point Metal

Continuous glucose monitoring (CGM) plays an important role in the treatment of diabetes. Affinity sensing based on the principle of reversible binding to glucose does not produce intermediates, and the specificity of concanavalin A (Con A) to glucose molecules helps to improve the anti-interference performance and long-term stability of CGM sensors. However, these affinity glucose sensors have some limitations in their linearity with a large detection range, and stable attachment of hydrogels to sensor electrodes is also challenging. In this study, a capacitive glucose sensor with high linearity and a wide detection range was proposed based on a glucose-responsive DexG–Con A hydrogel and a serpentine coplanar electrode made from a low-melting-point metal. The results show that within the glucose concentration range of 0–20 mM, the sensor can achieve high linearity (R2 = 0.94), with a sensitivity of 33.3 pF mM−1, and even with the larger glucose concentration range of 0–30 mM the sensor can achieve good linearity (R2 = 0.84). The sensor also shows resistance to disturbances of small molecules, good reversibility, and long-term stability. Due to its low cost, wide detection range, high linearity, good sensitivity, and biocompatibility, the sensor is expected to be used in the field of continuous monitoring of blood glucose