Synthesis of wafer-scale graphdiyne/graphene heterostructure for scalable neuromorphic computing and artificial visual systems

Graphdiyne (GDY) is emerging as a promising material for various applications owing to its unique structure and fascinating properties. However, the application of GDY in electronics and optoelectronics are still in its infancy, primarily owing to the huge challenge in the synthesis of large-area and uniform GDY film for scalable applications. Here a modified van der Waals epitaxy strategy is proposed to synthesize wafer-scale GDY film with high uniformity and controllable thickness directly on graphene (Gr) surface, providing an ideal platform to construct large-scale GDY/Gr-based optoelectronic synapse array. Essential synaptic behaviors have been realized, and the linear and symmetric conductance-update characteristics facilitate the implementation of neuromorphic computing for image recognition with high accuracy and strong fault tolerance. Logic functions including “NAND” and “NOR” are integrated into the synapse which can be executed in an optical pathway. Moreover, a visible information sensing-memory-processing system is constructed to execute real-time image acquisition, in situ image memorization and distinction tasks, avoiding the time latency and energy consumption caused by data conversion and transmission in conventional visual systems. These results highlight the potential of GDY in applications of neuromorphic computing and artificial visual systems.

     

离子色谱法检测硝酸盐亚硝酸盐前处理方法的研究

目的 利用离子色谱法检测乳及乳制品中亚硝酸盐、硝酸盐,在实际检测中用该国标方法在前处理样品时,存在沉淀样品不完全进而影响检测准确性、重复性不理想的弊端,为提高检测的准确性,缩小检测偏差,需对国标方法中样品的前处理改进。方法 样品经乙腈沉淀脂肪蛋白质后,采用相应的方法提取和净化,以氢氧化钾溶液为淋洗液,阴离子交换柱分离,电导检测器检测。以保留时间定性,外标法定量。结果 该方法克服了乳及乳制品GB5009.33-2010第三法检测检出限高及检测用时长,精密度低的的弊端。结论本方法适合于乳及乳制品定量测定。     

多重荧光PCR鉴别羊肉掺假

目的建立可同时检测掺入羊肉中的猪、马、牛、鸭成分的多重荧光PCR检测体系。方法配制掺入猪、马、牛、鸭源性成分的模拟羊肉掺假样品,掺假比例17%~45%。筛选特异性强、敏感度高的猪、马、牛、鸭物种特异性基因,优化反应体系,建立了针对猪、牛、马、鸭两两配对的两重荧光PCR检测体系和其中3个任意组合的三重荧光PCR检测体系。结果模拟羊肉掺假样品两重荧光PCR检测结果显示,包括单个成分掺入比例低至7%的样品,其检测准确率为100%。而三重荧光PCR检测同时检测猪、牛、马、鸭四种肉品中的3种,其中猪肉、牛肉和马肉的掺假比例均为8%~15%;鸭牛肉掺假比例为5%~10%。三重荧光PCR检测结果显示,所有掺假样品中的各种掺假组分都被准确检出。结论本研究建立的多重荧光PCR检测体系能准确检出配制的模拟掺假羊肉制品中的猪、马、牛、鸭成分,可进一步研究以应用于市场肉制品及加工肉制品掺假的检测。     

乳杆菌来源碳量子点的制备及其生防作用

目的建立一种利用乳杆菌制备量子点的方法,并用于防治细菌病害。方法采用水热法将干酪乳杆菌FJAT-13741、发酵乳杆菌FJAT-46744和植物乳杆菌FJAT-7926等3种乳杆菌分别制备了CDs-C(FJAT-13741)、CDs-F(FJAT-46744)和CDs-P(FJAT-7926)3种碳量子点,并采用透射电镜、红外光谱、XRD和荧光分析对碳量子点进行表征。选取青枯雷尔氏菌FJAT-91和地毯草黄单胞菌FJAT-10151作为实验菌种,采用抑菌圈法分别对3种碳量子点的抑菌性能进行研究。结果碳量子点CDs-C、CDs-F和CDs-P对青枯雷尔氏菌和地毯草黄单胞菌均有明显的抑制作用,其中, CDs-C的抑制效果最好。CDs-C碳量子点近似球形,粒径均匀(3 nm),分散性好,其发射波长依赖于激发波长,在紫外灯的照射下,出现明亮的蓝色荧光。结论本研究获得了一种对青枯雷尔氏菌和地毯草黄单胞菌有良好抑制效果的乳杆菌来源的量子点。     

细菌纤维素的生物合成及在食品工业的应用

细菌纤维素是经微生物发酵形成的新型生物合成材料,具有机械强度高、吸水性能好、纯度高、结晶度高等优良特性,广泛应用于食品工业等领域。已报道的产细菌纤维素的细菌有醋酸菌属(Acetobacter)、根瘤菌属(Rhizobium)、八叠球菌属(Sarcina)、土壤杆菌属(Agrobaeterium)、假单胞菌属(Preudomonas)、无色杆菌属(Achromobacter)、固氮菌属(Azotobacter)、气杆菌属(Aerobacter)和产碱菌属(Alcaligenes)这9个属中的某些种,真正能够应用于工业化生产细菌纤维素的只有醋酸菌中的几个种,他们是木醋杆菌(Acetobacter xylinum)、醋化醋杆菌(Acetobacteraceti)、产醋醋杆菌(Acetobacteracotigenum)和巴氏醋杆菌(Acetobacter pastcurianum)。本文通过分析近期国内外与细菌纤维素相关文献,对其高产菌种选育、培养基优化和发酵模式等方面的研究进行综述,并展望其在食品工业中的应用前景,为进一步深入研究细菌纤维素提供理论基础和科学依据。     

牛轧糖质构改进的意见

本文介绍了应用砂衡粉,精制淀粉改进传统的砂质型牛轧糖生产工艺的研究。使用一定细度的砂糖粉,可简化繁烦的砂质型牛轧糖工艺,添加淀粉有助于产品细腻,降低甜度。一般添加 100目的砂糖粉6%,精淀粉6%可以保证获得最佳效果。     

Non-Volatile Electrolyte-Gated Transistors Based on Graphdiyne/MoS2 with Robust Stability for Low-Power Neuromorphic Computing and Logic-In-Memory

Artificial synapses are the key building blocks for low-power neuromorphic computing that can go beyond the constraints of von Neumann architecture. In comparison with two-terminal memristors and three-terminal transistors with filament-formation and charge-trapping mechanisms, emerging electrolyte-gated transistors (EGTs) have been demonstrated as a promising candidate for neuromorphic applications due to their prominent analog switching performance. Here, a novel graphdiyne (GDY)/MoS₂-based EGT is proposed, where an ion-storage layer (GDY) is adopted to EGTs for the first time. Benefitting from this Li-ion-storage layer, the GDY/MoS₂-based EGT features a robust stability (variation < 1% for over 2000 cycles), an ultralow energy consumption (50 aJ µm⁻²), and long retention characteristics (>10⁴ s). In addition, a quasi-linear conductance update with low noise (1.3%), an ultrahigh G_max/G_min ratio (10³), and an ultralow readout conductance (<10 nS) have been demonstrated by this device, enabling the implementation of the neuromorphic computing with near-ideal accuracies. Moreover, the non-volatile characteristics of the GDY/MoS₂-based EGT enable it to demonstrate logic-in-memory functions, which can execute logic processing and store logic results in a single device. These results highlight the potential of the GDY/MoS₂-based EGT for next-generation low-power electronics beyond von Neumann architecture.     

An Ultrafast Nonvolatile Memory with Low Operation Voltage for High-Speed and Low-Power Applications

Memory plays a vital role in modern information society. High-speed and low-power nonvolatile memory is urgently demanded in the era of big data. However, ultrafast nonvolatile memory with nanosecond-timescale operation speed and long-term retention is still unavailable. Herein, an ultrafast nonvolatile memory based on van der Waals heterostructure is proposed, where a charge-trapping material, graphdiyne (GDY), serves as the charge-trapping layer. With the band-engineered heterostructure and excellent charge-trapping capability of GDY, charges are directly injected into the GDY layer and are persistently captured by the trapping sites in GDY, which result in an ultrafast writing speed (8 ns), a low operation voltage (30 mV), and a long retention time (over 10⁴ s). Moreover, a high on/off ratio of 10⁶ is demonstrated by this memory, which enables the achievement of multibit storage with 6 discrete storage levels. This device fills the blank of ultrafast nonvolatile memory technology, which makes it a promising candidate for next-generation high-speed and low-power-consumption nonvolatile memory.     

马苏里拉奶酪中纳他霉素含量的测定优化

目的 建立一种马苏里拉奶酪中纳他霉素含量的检测方法。方法 马苏里拉奶酪经甲醇提取，采用离心的方式净化，采用液相色谱-紫外检测器测定，外标法定量。结果 纳他霉素在1.0-5.0μg/mL的范围内，浓度与峰面积采用幂函数方程绘制标准曲线，相关系数大于0.99；方法定量检出限为0.2 mg/kg；样品的加标平均回收率为91.0%-101.2%；相对标准偏差为0.008%-0.054%；结论 本文研究的检测方法，样品前处理步骤简单，快速，离心后蛋白沉淀效果好，检测结果及仪器条件稳定，检测结果准确，满足实验需求。     

离子色谱法测定奶粉中胆碱含量方法的研究

目的 丰富奶粉中胆碱含量测定的方法, 同时对其他同类产品中胆碱含量的测定提供参考。方法 样品经盐酸水解, 水解液五倍稀释后采用离子色谱仪进行测定。结果 离子色谱法对胆碱含量测定的最低检测限为2 mg/kg, 相关系数达到0.9998, 添加回收率为88.7%~102.5%, 平行样标准偏差为0.72~4.15 mg/100 g, 相对标准偏差为0.66%~3.30%。结论 该方法操作简单, 灵敏度高, 选择性强, 能克服传统方法中繁琐、准确度低等缺陷和不足。