中国体育用品出口贸易效率与潜力研究——基于随机前沿引力模型的实证分析

基于随机前沿引力模型,结合2010—2020年30个具有代表性的国家(地区)面板数据,运用Frontier4.1软件研究我国体育用品出口贸易效率、潜力及其具体影响因素。研究表明:整体上中国体育用品出口贸易效率和潜力较高,但主要出口市场趋于饱和,增长空间较为有限。中国与伙伴国的经济发展水平、伙伴国的人口规模与中国体育用品出口显著正相关,而中国的人口规模和贸易双方的地理距离与中国体育用品出口显著负相关;中国与伙伴国签署自贸协定、伙伴国较高的海运能力、伙伴国政府较高的廉洁度和支出水平在提升贸易效率方面作用明显,而伙伴国较高的关税水平和金融自由度则限制了贸易效率的提高。建议合理配置贸易资源,优化国际市场布局;商签高标准贸易协定,开拓新兴国际市场;坚持创新驱动战略,培植国际竞争新优势。     

一类二阶迭代泛函微分方程解析解的存在性

在复域C内研究一类含有未知函数迭代的二阶微分方程λ2x”（z）＋λ1x’（z）＋λ0x（z）=（x”（z））2的解析解的存在性。通过Schroder变换：x（z）=y（ay^-1（z））,把这类方程转化为一种不合未知函数迭代的泛函微分方程λ2[a^2y＂（az）y’（z）-ay’（az）y＂（z）]＋λ1ay’（az）（y’（z））^2＋λ0y（az）（y’（z））^3=（y’（z））^3（y（a^mz））^2,并给出了它的局部可逆解析解。不仅讨论了双曲型情形和共振的情形0〈｜α｜〈1,而且还在Brjuno条件下讨论了在共振点附近的情形。     

量子信息处理及其核磁共振实现（英文）

量子特性在信息领域中有着独特的功能,在提高运算速度、确保信息安全、增大信息容量和提高检测精度等方面可能突破现有经典信息系统的极限。我们以液态NMR技术实现量子信息处理中的应用主题开展研究,所取得的成果包括：1）利用NMR实验实现了两个无直接耦合自旋之间的量子密集编码和三个量子位之间的量子密集编码过程。实验结果表明：量子密集编码只需传送N-1个量子位便可以传递N个经典位的信息。2）利用NMR实验实现了三种多量子算法;提出了一种实现n阶耦合变换的理论方法,根据这种方法可实现任意量子位的Deutsch-Jozsa算法。3）提出了一种基于量子克隆的量子编码和纠错方案。该方案一方面说明了量子克隆与量子纠错存在一定程度上的联系,另一方面也反映出一些量子克隆过程本身具有一定的抗消相干的能力。4）提出用二维NMR中的多量子相干实现无消相干子空间（DFS）,并在实验上验证了该DFS的避错能力。本方法有效地利用了甲基中三个磁等价的氢核,把原本需要四个化学位移各不相同的核自旋构造的二逻辑位的DFS变成了只需两个化学位移各不相同的核自旋体系构造的二逻辑位的DFS,虽然用的核自旋数“更少”,却能避免更多的错误算符。用多量子相干作为量子计算中的量子位,是一种全新的概念,可以充分利用磁等价的原子核自旋来构造多个量子位,从而扩展了可利用的量子位的数目。     

受迫振动的共振现象

对力学中遇到的受迫振动的各类共振现象进行了具体分析和深入讨论 ,给出了相应的共振频率 ,指出了其结论可移植到对应的系统中去     

磁场中导电矩形薄板1∶3内共振下的超谐波动力学响应

针对横向恒定磁场中一边固定三边简支的导电矩形薄板,研究1∶3内共振条件下系统发生超谐波共振时的动力学响应。利用伽辽金法得到两自由度非线性振动微分方程组,并通过数值计算得到系统发生超谐-内联合共振时前两阶模态的响应图。结果表明,内共振的存在使得高阶模态被间接激发,不同参数下系统呈现出混沌、概周期运动等复杂动力学响应,可以通过调节磁场强度控制系统振动。     

A CRISPR/Cas12a-empowered surface plasmon resonance platform for rapid and specific diagnosis of the Omicron variant of SARS-CoV-2

The outbreak of the COVID-19 pandemic was partially due to the challenge of identifying asymptomatic and presymptomatic carriers of the virus, and thus highlights a strong motivation for diagnostics with high sensitivity that can be rapidly deployed. On the other hand, several concerning SARS-CoV-2 variants, including Omicron, are required to be identified as soon as the samples are identified as ‘positive’. Unfortunately, a traditional PCR test does not allow their specific identification. Herein, for the first time, we have developed MOPCS (Methodologies of Photonic CRISPR Sensing), which combines an optical sensing technology-surface plasmon resonance (SPR) with the ‘gene scissors’ clustered regularly interspaced short palindromic repeat (CRISPR) technique to achieve both high sensitivity and specificity when it comes to measurement of viral variants. MOPCS is a low-cost, CRISPR/Cas12a-system-empowered SPR gene-detecting platform that can analyze viral RNA, without the need for amplification, within 38 min from sample input to results output, and achieve a limit of detection of 15 fM. MOPCS achieves a highly sensitive analysis of SARS-CoV-2, and mutations appear in variants B.1.617.2 (Delta), B.1.1.529 (Omicron) and BA.1 (a subtype of Omicron). This platform was also used to analyze some recently collected patient samples from a local outbreak in China, identified by the Centers for Disease Control and Prevention. This innovative CRISPR-empowered SPR platform will further contribute to the fast, sensitive and accurate detection of target nucleic acid sequences with single-base mutations.     

试论男高音训练中的几个重要环节

在声乐教学中 ,我们发现大部分男声是男高音 ,但真正唱得好的男高音却寥寥无几。唱高音一定要有方法和技巧。首先要正确地打开喉咙 ,让声音自然、通畅。歌唱时气息支持 ,除用横隔膜力量向下推压向外扩以外 ,后背的肌肉力量对高音的支持也同样重要。更多地运用共鸣 ,细心唱好“过渡”音是高音的必由之路。头腔共鸣是男高音的重要共鸣腔体。为了保持高音的灵活性 ,每天要练习各种音阶     

Neumann展开Monte Carlo随机无网格伽辽金法的镗刀位移变异分析

本文用Neumann展开Monte Carlo随机无网格伽辽金法（NMC—SEFGM）进行了随机结构分析。在随机无网格伽辽金法中，所求解问题的域由分布的节点表示，并采用移动最小二乘函数近似试函数以及用罚函数法施加本质边界条件。同时利用Neumann展开法，建立了随机结构分析的Neumann展开Monte Carlo随机无网格伽辽金法，并应用于镗刀杆工作位移的变异分析。数值实例表明Neumann展开Monte Carlo随机无网格伽辽金法适用于材料变异系数大和要求精度高的随机结构分析。     

两参数随机过程的可测性

给出了两参数随机过程的可测性及循序可测性的条件.     

Study of clinical features of amyloid angiopathy hemorrhage and hypertensive intracerebral hemorrhage

Objective: The purpose of this study was to differentiate between cerebral amyloid angiopathy (CAA) and hypertension (HTN) based on hemorrhage pattern interpretation. Methods: From June 1994 to Oct., 2000, 83 patients admitted to our service with acute intracerebral hemorrhage (ICH) were investigated retrospectively; 41 patients with his-tologically proven diagnosis of cerebral amyloid angiography and 42 patients with clear history of hypertension were investigated. Results: Patients with a CAA-related ICH were significantly older than patients with a HTN-related ICH (74.0 years vs 66.5 years, P<0.05). There was a significantly higher number of hematomas>30 ml in CAA (85.3%) when compared with HTN (59.5%). No basal ganglional hemorrhage was seen in CAA, but in 40.5% in HTN. In CAA-related ICH, su-barachnoid hemorrhage (SAH) was seen in 26 patients (63.4%) compared to only 11 patients (26.2%) in HTN-related ICH. Intraventricular hemorrhage was seen in 24.4% in CAA, and in 26.2% in HTN. Typical features o