摘要：The photocatalytic production of syngas using a noble-metal-free catalytic system is a promising approach for renewable energy and environmental *** this study,we demonstrate an efficient catalytic system formed by integrating Co single sites,which act as the active sites,in covalent triazine frameworks(CTFs),which act as the photoabsorber,for the photocatalytic production of syngas from CO2 in aqueous *** enhanced light absorption of the CTFs,which contain intramolecular heterojunctions,in conjunction with 0.8 mmol L^‒1 of the Co complex enables excellent syngas production with a yield of 3303μmol g‒1(CO:H2=1.4:1)in 10 h,which is about three times greater than that achieved using CTF without a *** the photocatalytic reaction,the coordinated single Co centers accept the photogenerated electrons from the CTF,and serve as active sites for CO2 conversion through an adsorption-activation-reaction *** calculations further reveal that the intramolecular heterojunctions highly promote photogenerated charge separation,thus boosting photocatalytic syngas *** work reveals the promising potential of CTFs for single-metal-site-based photocatalysis.

摘要：Personalized microblog recommendations face challenges of user cold-start problems and the interest evolution of topics. In this paper, we propose a collaborative filtering recommendation algorithm based on a temporal interest evolution model and social tag prediction. Three matrices are first prepared to model the relationship between users, tags, and microblogs. Then the scores of the tags for each microblog are optimized according to the interest evolution model of tags. In addition, to address the user cold-start problem, a social tag prediction algorithm based on community discovery and maximum tag voting is designed to extract candidate tags for users. Finally, the joint probability of a tag for each user is calculated by integrating the Bayes probability on the set of candidate tags, and the top n microblogs with the highest joint probabilities are recommended to the user. Experiments using datasets from the microblog of Sina Weibo showed that our algorithm achieved good recall and precision in terms of both overall and temporal performances. A questionnaire survey proved user satisfaction with recommendation results when the cold-start problem occurred.

摘要：通过长达10年对广州地铁6号线柯木塱站及邻近盾构隧道沉降监测成果的统计,分析沉降形态和规律,并结合地质调查,认为形成沉降的原因是:沉降地段位于不良地质条件的花岗岩风化(深)槽区段,上覆有全新世古河道沉积的富水砂层;随着人口增加,地下水抽采量倍增;地面硬化、有组织排水等工程的实施,使天然雨水渗入地下的水量大大降低,雨水-地下水循环失衡,三者的耦合作用,导致该区域地下水位持续下降,隧道、车站以及地面也同步正相关沉降。针对上述问题,采用控制超采地下水和改扩容公共自来水的措施,实施后地下水位明显抬升,地面和隧道沉降速率大幅下降,局部点有所抬升,隧道趋稳。

摘要：Gravity-1(YL-1) launch vehicle completed its maiden flight from the Yellow Sea near Haiyang City, Shandong Province, on January 11, 2024, this mission successfully launched three Yunyao satellites into their 500 km orbit. The YL-1 has a performance of 4.2 tons for 500 km sun-synchronous orbit and 6.5 tons for low Earth orbit. The success of YL-1 has further enriched china's launch vehicle spectrum, and will facilitate the launch of medium and large satellites and satellite constellations. In this paper, the flight ballistic solution of YL-1 is introduced. The flight trajectory consists of seven flight segments. The trajectory design comprehensively considered the characteristics and safety requirements of the vehicle to achieve effective utilization of the performance. Through comparative analysis of the flight trajectory and the predicted trajectory, the result confirmed that the flight trajectory was consistent with the design results, the design methodology was correct, and the flight test met the expected requirements. Subsequently, the vehicle will be employed for commercial application launch services.

摘要：针对旋翼/螺旋桨的大负扭和后掠桨尖设计在桨叶内部所带来的严重应力应变集中问题,结合三维结构动力学模型、旋翼气动模型和旋翼配平方法,对复合材料旋翼/螺旋桨进行了综合建模与气弹载荷分析,并通过悬停实验验证了综合模型的准确性。对比分析了无负扭、大负扭和大负扭带后掠桨尖的桨叶气弹特性,发现大负扭导致桨叶应力集中区域扩大,后掠桨尖使桨尖过渡区域的应力集中区域扩大,集中程度加剧。

摘要：本论文通过研究国内外公共艺术雕塑设施案例,将建构人群集体记忆,唤醒共有情感作为研究重点,对居住公共空间的发展历程以及公共艺术设施的系统性和独特性相关理论进行归纳分析,完成对城市历史文化和群体意识的了解,对老旧小区现存的空间问题进行研究。提出将人文精神概念融入公共艺术设施、建造拥有集体记忆的公共空间的作为改造思路,旨在创造出符合当下老旧小区老龄化需求、地域文化保护措施的公共艺术雕塑。

摘要：为提高远程光体积描记术(remote photoplethysmography,rPPG)在自然场景中心率(heart rate,HR)估计的精度,提出一种基于多头自注意力的多任务心率估计模型。设计一种特征表示方法将视频转换为时空表示,抑制非皮肤区域和背景引入的噪声;使用改进的多头自注意力模型学习长距离帧之间的依赖关系,解决rPPG对光照变化和头部运动鲁棒性不足的问题;将学习到的特征用于估计rPPG信号和HR两个任务,通过rPPG信号的频域约束HR,提高心率估计精度。实验结果表明,提出方法在UBFC-RPPG和PURE两个公开数据集上的心率估计准确度优于对比方法,验证了其有效性。

摘要：针对现有纯电动汽车热泵空调在低温气候下由于车外换热器结霜导致的制热性能低的问题,提出一种利用电机余热增强热泵空调制热性能,同时加热电池的纯电动车整车制热系统。在AMESim软件中建立了整车制热系统模型,分别在环境温度为0、-10和-20℃情况下进行仿真分析。研究结果表明:新系统乘员舱制热和电池加热效果较好;在环境温度为-20℃,1个WLTC工况循环下,相比于传统热泵空调,新系统能大大缩短乘员舱制热时间且制热效率提高了27.4%;与电池自生热加热相比,新系统中电池加热效果提高了79.7%,整车电能消耗减少16.7%。

摘要：精密定位平台由于机械摩擦造成精度受限,难以满足大行程、高精度定位的运动要求。本文结合宏微复合结构,提出了一种单驱动刚柔耦合定位平台。相对于现有的宏微复合平台,大幅简化了机械结构和运动控制系统的设计。基于浮动坐标法和有限元法建立了单驱动刚柔耦合定位平台的静力学和动力学模型,并与商业软件ABAQUS及简化解析模型的分析结果进行对比,最大相对误差分别为1.6%和3.72%,证明了该理论模型具有较高的预测精度,可为刚柔耦合平台的优化设计及精密运动控制提供参考。

摘要：以轴流排烟风机翼型为研究对象,对Joukowsky翼型型线表达式进行了简化,获得了2个由六参数确定的翼型形状函数表达式,可以分别对翼型上下型线进行表示,对各参数应满足的范围进行了分析。通过Isight平台集成CFD软件,对标准翼型NACA0012进行了优化设计,结果显示:翼型升阻比系数提升了22.4%,升力系数提升了18.0%,气动性能得到了显著提升。由此证明,基于该形状函数法进行排烟风机翼型的优化设计是可行的,为今后风机性能的改进打下了基础。