Low-damage interface enhancement-mode AlN/GaN high electron mobility transistors with 41.6% PAE at 30 GHz

This paper reports a low-damage interface treatment process for Al N/Ga N high electron mobility transistor(HEMT)and demonstrates the excellent power characteristics of radio-frequency(RF) enhancementmode(E-mode) Al N/Ga N HEMT. An RF E-mode device with 2.9-nm-thick Al N barrier layer fabricated by remote plasma oxidation(RPO) treatment at 300℃. The device with a gate length of 0.12-μm has a threshold voltage(Vth) of 0.5 V, a maximum saturation current of 1.16 A/mm, a high Ion/Ioff ratio of 1×108, and a 440-m S/mm peak transconductance. During continuous wave(CW) power testing, the device demonstrates that at 3.6 GHz, a power added efficiency is 61.9% and a power density is 1.38 W/mm, and at 30 GHz, a power added efficiency is 41.6% and a power density is 0.85 W/mm. Furthermore, the RPO treatment improves the mobility of RF E-mode Al N/Ga N HEMT. All results show that the RPO processing method has good applicability to scaling ultrathin barrier E-mode Al N/Ga N HEMT for 5G compliable frequency ranging from sub-6 GHz to Ka-band.

Enhanced Efficiency of Metamorphic Triple Junction Solar Cells for Space Applications

Metamorphic In0.55Ga0.45P/In0.06Ga0.94As/Ge triple-junction （3J-MM） solar cells are grown on Ge （100） sub- strates via metal organic chemical vapor deposition. Epi-structural analyses such as high resolution x-ray diffrac- tion, photoluminence, cathodoluminescence and HRTEM are employed and the results show that the high crystal quality of 3J-MM solar cells is obtained with low threading dislocation density of graded buffer （an average value of 6.8× 10^4/cm2）. Benefitting from the optimized bandgap combination, under one sun, AM0 spectrum, 25℃ conditions, the conversion efficiency is achieved about 32%, 5% higher compared with the lattice-matched In0.49Ga0.51P/In0.01Ga0.99As/Ge triple junction （3J-LM） solar cell. Under 1-MeV electron irradiation test, the degradation of the EQE and I-V characteristics of 3J-MM solar cells is at the same level as the 33-LM solar cell. The end-of-life efficiency is -27.1%. Therefore, the metamorphic triple-junction solar cell may be a promising candidate for next-generation space multi-junction solar cells.

Efficiency of Blue Organic Light-emitting Diodes Enhanced by Employing an Exciton Feedback Layer

We report that a novel exciton feedback effect is observed by introducing the bis（2-methyl-8-quinolinolato）（4- phenylphenolato）Muminum （BAlq） inserted between the emitting layer （EML） and the electron transporting layer in blue organic light emitting diodes. As an exciton feedback layer （EFL）, the BAlq does not act as a traditional hole blocking effect. The design of this kind of device structure can greatly reduce excitons＇ quenching due to accumulated space charge at the exciton formation interface. Meanwhile, the non-radiative energy transfer from EFL to the EML can also be utilized to enhance the excitons＇ formation, which is confirmed by the test of photolumimescent transient lifetime decay and electroluminescence enhancement of these devices. Accordingly, the optimal device presents the improved performances with the maximum current efficiency of 4.2 cd/A and the luminance of 24600cd/m2, which are about 1.45 times and 1.75 times higher than those of device A （control device） without the EFL, respectively. Simultaneously, the device shows an excellent color stability with a tiny offset of the CIE coordinates （△x = ±0.003, △y = ±0.004） and a relatively lower efficiency roll-off of 26.2% under the driving voltage varying from 3 V to 10 V.

A Facile Route to Cotton-Like BiOCl Nanomaterial with Enhanced Dye-Sensitized Visible Light Photocatalytic Efficiency

A facile route is developed to fabricate BiOCI porous cotton-like nanostructure by using Bi203 and hydrochlo- ric acid as raw materials. The BiOCI nanomaterial is actually hierarchically structured by numerous ultrathin nanosheets. The nanosheets are around 50-500 nm in lateral size and 2-12 nm in thickness. High-resolution trans- mission electron microscopy and selected-area electron diffraction analyses indicate that single-crystalline BiOCl nanosheets have the predominant growth direction along [110], the bottom and top surfaces are {001} facets, and four lateral surfaces are {110} facets. The BiOCl nanosheets are dominantly enclosed by {001} facets. From the diffuse reflectance spectroscopy spectrum, the light absorption edge and band gap energy （Eg） are estimated to be 416 nm and 2.98eV, respectively. The BiOCl photocatalyst possesses superior activity for methyl orange （MO） degradation under visible light irradiation and the photodegradation efficiency is up to 91.5%/180 min. The correlation between morphology and microstructure with enhanced MO-sensitized photodegradation performance under visible light is investigated.

Electronegativity explanation on the efficiency-enhancing mechanism of the hybrid inorganic–organic perovskite ABX_3 from first-principles study

Organic–inorganic hybrid perovskites play an important role in improving the efficiency of solid-state dye-sensitized solar cells. In this paper, we systematically explore the efficiency-enhancing mechanism of ABX_3（A = CH_3NH_3; B = Sn,Pb; X = Cl, Br, I） and provide the best absorber among ABX_3 when the organic framework A is CH_3NH_3 by first-principles calculations. The results reveal that the valence band maximum（VBM） of the ABX_3 is mainly composed of anion X p states and that conduction band minimum（CBM） of the ABX_3 is primarily composed of cation B p states. The bandgap of the ABX_3 decreases and the absorptive capacities of different wavelengths of light expand when reducing the size of the organic framework A, changing the B atom from Pb to Sn, and changing the X atom from Cl to Br to I. Finally, based on our calculations, it is discovered that CH_3NH_3 Sn I_3has the best optical properties and its light-adsorption range is the widest among all the ABX_3 compounds when A is CH_3NH_3. All these results indicate that the electronegativity difference between X and B plays a fundamental role in changing the energy gap and optical properties among ABX_3 compounds when A remains the same and that CH_3NH_3 Sn I_3 is a promising perovskite absorber in the high efficiency solar batteries among all the CH_3NH_3BX_3 compounds.

HIGH EFFICIENCY COOLING TECHNOLOGY BASED ON GREEN MANUFACTURING

Green manufacturing （GM） and high efficiency machining technology are inevitable trends in the field of advanced manufacturing of the 21st century. To ensure green and high-efficiency machining, a new high efficiency cooling technology-cryogenic pneumatic mist jet impinging cooling （CPMJI） technology is presented. For obtaining the best cooling effect, a little quantity of coolant is carried by high speed cryogenic air （-20 C ） and reaches the machining zone in the form of mist jet to enhance heat transfer. Experimental results indicate that under the conditions of 40 m/s in the jet impinging speed and 10 mm in the jet impinging distance, the critical heat flux（CHF） nearly reaches 6× 10^7 W/m^2, more than six times of the CHF of the grinding burn with a value of （8～10）×10^6 W/m^2.

A 1V,156.7μW,65.9dB Rail-to-Rail Operational Amplifier by Means of Negative Resistance Load and Replica-Amplifier Gain Enhancement

A low-voltage, low-power, and high-gain rail-to-rail operational amplifier （OpAmp） is presented. The replica-amplifier gain enhancement technique is applied to improve the DC gain of the amplifier, which does not degrade the output swing and is very suitable for low-voltage applications. In a 0. 18/μm standard CMOS process,a 1V OpAmp with rail-to-rail output is designed. For a load capacitance of 5 pF,simulation by HSPICE shows that this OpAmp achieves an effective open-loop DC gain of 65. 9dB,gain bandwidth of 70.28 MHz,and phase margin of 50 with a quiescent power dissipation of 156.7μW.

Study on Potential and Countermeasures of Artificial Precipitation Enhancement in Fuxin Region

To exploit cloud water resources to increase precipitation on the ground effectively,according to the principles of artificial precipitation enhancement,based on historical data of weather and precipitation from Fuxin National Basic Meteorological Stations from 1981 to 2010,the distribution characteristics of cloud water resources,potential and countermeasures of artificial precipitation enhancement in Fuxin region of Liaoning Province were studied. The results show that the annual average quantity of cloud water resources in the air over Fuxin region over the past 30 years was 285. 6 × 10~8m^3,but the annual average precipitation was only 471.8 mm( amounting to 47.2 ×10~8m^3 of water resources),accounting for only16. 5% of total quantity of cloud water resources in the air; 12 times of artificial precipitation enhancement operation experiments were carried out by using the weather models and technical indicators suitable for artificial precipitation enhancement in Fuxin region,and the artificial precipitation efficiency was 18. 3% on average,5. 2% higher than before,and the annual average precipitation could increase by 2. 5 × 10~8m^3 approximately. All of these have great significance for implementing artificial precipitation enhancement operation scientifically and effectively,maximizing the exploitation of cloud water resources in the air,increasing total quantity of water resources,and mitigating drought in Fuxin region.

Small Cell Enhancement物理层关键技术研究

作为移动网络解决热点覆盖和数据分流的有效途径,Small Cell在实际部署时仍面临着小区间干扰、移动性管理、回程承载、负荷均衡、维护和优化等难题。为有效克服和优化这些问题,在其演进技术Small Cell Enhancement中,分别从提高频谱效率和协作能力2个方向在关键的物理层提出了一系列潜在技术方案,从而进一步提高系统容量、均衡系统负载,同时更好地兼容现有LTE/LTE-A网络体系。

Clustering-based adaptive low-power subframe configuration with load-aware offsetting in dense heterogeneous networks

Heterogeneous Networks(HetNets)and cell densification represent promising solutions for the surging data traffic demand in wireless networks.In dense HetNets,user traffic is steered toward the Low-Power Node(LPN)when possible to enhance the user throughput and system capacity by increasing the area spectral efficiency.However,because of the transmit power differences in different tiers of HetNets and irregular service demand,a load imbalance typically exists among different serving nodes.To offload more traffic to LPNs and coordinate the Inter-Cell Interference(ICI),Third-Generation Partnership Project(3GPP)has facilitated the development of the Cell Range Expansion(CRE),enhanced Inter-Cell Interference Coordination(eICIC)and Further enhanced ICIC(FeICIC).In this paper,we develop a cell clustering-based load-aware offsetting and an adaptive Low-Power Subframe(LPS)approach.Our solution allows the separation of User Association(UA)functions at the User Equipment(UE)and network server such that users can make a simple cell-selection decision similar to that in the maximum Received Signal Strength(max-RSS)based UA scheme,where the network server computes the load-aware offsetting and required LPS periods based on the load conditions of the system.The proposed solution is evaluated using system-level simulations wherein the results correspond to performance changes in different service regions.Results show that our method effectively solves the offloading and interference coordination problems in dense HetNets.

A novel nanofluid of modified carbon black nanoparticles for enhanced oil recovery in low permeability reservoirs

A novel nanofluid of modified carbon black(MCB)nanoparticles was initially developed for enhanced oil recovery(EOR)in low permeability reservoirs.The MCB nanoparticles were obtained via a three-step reaction involving modification by oxidation,acyl chlorination,and activated grafting.MCB nano-particles were spherically dispersed,with an average size of 72.3 nm.Compared with carbon black(CB)nanoparticles,dispersed MCB nanoparticles can effectively reduce the oil-water interfacial tension(IFT)to 10^(-2)mN/m and change the surface wettability of sand particles.Based on the results of core flooding experiments,the MCB nanoparticles exhibited a better EOR capacity than surfactants and CB nano-particles,and the final oil recovery was significantly increased by 27.27%.The core scanning test showed that the MCB nanoparticles could plug high permeability channels by adsorbing onto the surfaces of sand particles and forming larger aggregates that bridge across pores or throats,resulting in a higher swept volume.The synergistic effects of improved swept volume and oil displacement efficiency were the EOR mechanisms of the MCB nanoparticles.The studies indicate that these MCB nanoparticles have excellent potential for EOR in low permeability reservoirs.

Development of an Enhanced Self-Tuning RBF-PID Controller for Achieving Higher Energy-Efficient Process Control

Proportional, integral and derivative (PID) control strategy has been widely applied in heating systems in decades. To improve the accuracy and the robustness of PID control, self-tuning radial-basis-function neural network PID (RBF-PID) is developed and used. Even though being popular, during the control process both of PID and RBF-PID control strategy are inadequate in achieving simultaneous high energy-efficiency and good control accuracy. To address this problem, in this paper we develop and report an enhanced self-tuning radial-basis-function neural network PID (e-RBF-PID) controller. To identify the superiority of e-RBF-PID, following works are conducted and reported in this paper. Firstly, four controllers, i.e., on-off, PID, RBF-PID and e-RBF-PID are designed. Secondly, in order to test the performance of the e-RBF-PID controller, an experimental water heating system is constructed for being controlled. Finally, the energy consumption for the four controllers under the three control scenarios is investigated through experiments. The experimental results indicate that in the three scenarios, the developed e-RBF-PID controller outperforms on-off controller as having higher accuracy. Compared to the PID controller, the e-RBF-PID controller has higher speed in control, and the experimental results show that settling time savings is between 12.6% - 49.0%. Most importantly, less control energy consumption is obtained if using the e-RBF-PID controller. It is found that up to 28.5% energy consumption can be saved. Therefore, it is concluded that the proposed e-RBF-PID is capable of enhancing energy efficiency during control process.

增效型无土相仿生油基钻井液技术的研究与应用

针对深井超深井钻井过程中钻遇高温高压、井壁失稳及井下复杂情况的难题,基于仿生学、超分子化学以及岩石表面润湿性理论,通过优选仿生增效剂、仿生提切剂及仿生降滤失剂,配套相关处理剂,最终形成了一套适用于深井、超深井地层钻探的增效型无土相仿生油基钻井液体系。研究发现,建立的增效型无土相仿生油基钻井液体系可抗220℃高温,配制密度为2.4 g/cm^(3),破乳电压大于400 V,高温高压滤失量为3.2 mL,人造岩心在该体系中220℃下老化后的抗压强度达到7.1 MPa,平均渗透率恢复值为93.9%。现场应用情况表明,体系流变性能稳定,平均机械钻速比邻井提高16%,平均井径扩大率仅为1.25%,可有效解决深井超深井钻井过程中出现的井壁失稳难题,为我国深井超深井的钻探提供了技术保障。

老油田“3+2”大幅度提高采收率技术内涵、机理及实践

传统方式的化学驱项目一般采取“2+3”的协同方式,也就是先通过水驱井网调整一次到位,再实施化学驱,受剩余油认识和预测精度的影响,会出现部分低产低效井,化学驱含水谷底平台期短,提高采收率幅度有限。为此,胜利油田通过基础攻关和探索实践,创新提出了化学驱与动态优化调整加合增效的“3+2”大幅度提高采收率技术,该技术是指在化学驱过程中,充分发挥和利用驱油体系扩大波及体积、提高驱油效率、调整动态非均质性的特点,主动培育、壮大动态剩余油富集区(“油墙”),适时井网调整、重构流场、均衡注采,高效动用、采出“油墙”,最大程度延长化学驱含水谷底平台期,实现三次采油和二次采油(“3+2”)适配优化、大幅度提高采收率的目的。通过大量物理模拟和数值模拟研究,明确了“井网-驱油剂-剩余油”适配优化提高采收率的机理。该技术在胜坨油田二区东三段5砂组进行了应用,通过优化“3+2”井网调整方式、驱油体系和注入参数等,预计区块含水谷底平台期从3 a延长至8 a,最终采收率为60.5%,比原方案采收率再提高7.5百分点。该技术是老油田大幅度提高采收率的关键技术,可以为中外同类型油藏延长化学驱见效高峰期提供指导和借鉴。

济阳坳陷页岩油注二氧化碳开发技术

围绕页岩油注CO_(2)开发存在的问题,通过室内实验、数值模拟与压裂工艺相结合的方式,开展了页岩油注CO_(2)萃取置换机理、CO_(2)前置液对页岩力学性质影响的室内实验,模拟了CO_(2)前置压裂和吞吐补能对开发效果的影响,并将成果应用于CO_(2)前置压裂和单井吞吐矿场实践。研究表明:CO_(2)吞吐作用效果受微纳尺度效应及干酪根、吸附油存在等的影响,适当延长焖井时间可提高原油动用程度。在CO_(2)“注、焖”阶段,CO_(2)通过溶解扩散和传质作用提高重烃的动用程度,在CO_(2)“吐”的阶段,CO_(2)主要将较大孔隙中的原油排出至周边更大的孔隙或层理缝中流入生产井。注入CO_(2)前置液有助于保持岩心脆性,降低破裂压力,CO_(2)易沿层理面滤失,从而提高裂缝复杂程度。前置CO_(2)注入量增加会提升增能效果,从而增强地层能量的补充作用。页岩基质渗透率越低、地层压力越低、原油重烃含量越高,注CO_(2)吞吐开发后,采收率提高幅度越大。矿场实践表明,CO_(2)前置压裂后压力保持良好,单井CO_(2)吞吐后可有效补充地层能量,提高单井产能,效果良好。

高温高盐油藏化学驱提高采收率理论技术与矿场应用

化学驱是提高采收率的重要方法之一,在油田高效开发中发挥了重要作用。基于中外化学驱技术的发展现状,针对高温高盐的苛刻油藏条件,系统总结了胜利油田化学驱提高采收率的理论技术。通过梳理胜利油田60a来化学驱技术从室内研究到矿场应用所攻克的理论和技术难题,介绍了高温高盐油藏化学驱的发展历程。通过认识驱油剂之间以及驱油剂与原油之间的相互作用和构效关系,迭代创建了高温高盐油藏聚合物“黏弹并重扩波及”理论、表面活性剂“油剂相似富集、阴非加合增效”理论和黏弹性颗粒“变形调驱”理论,并攻关形成了具有胜利特色的高温高盐油藏聚合物驱技术、无碱二元复合驱技术和非均相复合驱技术,攻克了温度为85℃、矿化度为30000 mg/L的油藏大幅度提高采收率的难题,矿场实施的96个化学驱项目的年产油量连续20a占油田年产油量的11%以上。该系列技术为胜利油田产量稳定和可持续发展做出了重要贡献。

生物化学复合提高采收率技术研究进展及发展趋势

系统调研了中外近10a来在生物化学复合提高采收率技术方面的室内研究及现场应用进展,分别从提高洗油效率和扩大波及体积2方面,就采油菌体、生物表面活性剂、生物多糖分别与表面活性剂、聚合物、纳米颗粒等化学采油制剂间的协同作用机理,体系构建及现场应用效果进行了分析。研究结果表明:生物菌体及其代谢产物与化学采油制剂复合后,在界面张力降低、乳化分散、流度比控制和稠油降黏等方面都具有协同增效作用,现场应用也取得了良好的效果,其中胜利油田探索了菌体复合聚合物调剖技术及微生物脱硫保黏技术,预测提高采收率分别为9%和10.3%,大庆油田开展生物表面活性剂三元复合驱现场应用,先导区提高采收率达到22%。生物化学复合提高采收率技术在老油田难采储量动用方面具有巨大的应用前景。下一步需继续深化生物、化学体系间协同增效机理,根据油藏平面及层间、层内的差异,创新生物、化学采油体系复合及实施工艺,细化不同开发阶段、不同油藏空间的实施方案,通过油藏立体均衡开发,最大限度发挥生物与化学复合增效技术优势,满足老油田可持续开发的需求。

我国微量元素肥料研究及应用的历程与展望

我国土壤中微量元素普遍缺乏,加之持续大量的氮、磷等化肥投入,加剧了土壤中微量元素的不足。微量元素缺乏已成为影响农作物生产的主要障碍之一,一些地方甚至成为人类微量元素缺乏的重要原因。施用微量元素肥料(以下简称微肥)是缓解植物微量元素缺乏的有效措施之一。我国较大规模、系统的微肥研究与应用始于20世纪70年代,微肥剂型经历了由传统无机盐类到螯合类、缓控释、纳米类等各种新型微肥的发展,微肥施用方式伴随微肥产品的创新而不断优化,微肥施用范围逐渐扩大到几乎所有作物类型。截至2024年4月中旬,大陆地区31个省级行政区除西藏外均有微量元素水溶肥料备案,山东和河南两省的备案数量最多,分别占全国的29.7%和26.2%。每年申请的微肥及制备方法相关专利数量在2011年后快速增加,到2016年达到年最高数量67项。然而,在农业农村部登记和备案的(含)微量元素肥料大多为复合型的水剂和粉剂,其他剂型产品很少。在实际生产中,基层科技人员和农民对微肥的认知依然不够,施用微肥后不能马上观察到显而易见的效果就怀疑微肥的功效,市场上微量元素肥料剂型单一,针对性不强,影响着微肥的研究应用与推广。从我国农业实际出发,今后需要加强以下几方面的工作:首先要协调微量元素与大量元素之间的均衡配比,建立适应“区域−土壤−作物”体系的微量元素养分综合管理体系;要持续研发环境友好且高效的微肥产品及配套技术,研究与轻减化施肥技术相适应的微肥剂型及其施用技术体系;此外,做好微肥质量监管,在基层中普及微肥的相关知识,提高对微肥重要性的认识,做到“产−学−研−管−用”一体化推进,促进我国微肥产业健康发展。

高温测量降本增效实践与研究

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