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الثقة في النظرية : نجاح لنظام التنمية (البديل) الخاص بالصين
جاء هذا الكتاب تحت عنوان «الثقة في النظرية : نجاح لنظام التنمية \"البديل\" الخاص بالصين» وهو من تأليف (مايا غيو) وترجمة عبد الرحمن النجار. يبحث الكتاب في التطور الصيني السريع خلال الستة عقود الماضية، والدور الذي لعبه الحزب الشيوعي الصيني في تحويل الصين إلى دولة اشتراكية حديثة مزدهرة وقوية وديمقراطية ومتطورة ثقافيا ويستكشف ويستكشف فيما إذا كان صعود الصين يهدد نموذج التنمية الغربي وخاصة بعد أن أضحى صعود الصين حقيقة لا جدال فيها. يعتبر هذا الكتاب من أنجح الكتب التي نشرت عن الصين اليوم. فهو يقدم حججا مقنعة حول نهوض الصين. وتستند الآراء المعبر عنها في الكتاب ليس فقط إلى 60 عاما من تاريخ جمهورية الصين الشعبية وإنجازاتها الملحوظة في العقود الثلاثة الماضية، ولكن أيضا على تاريخها الحديث منذ عام 1840، وتاريخها الذي دام 2000 عام كدولة موحدة، وحضارتها ذات ال 5000 سنة. وتعكس المقابلات التي أجرتها المؤلفة \"مايا غيو\" مراقبتها الدقيقة للصين اليوم. إذ تضمنت أشخاصا من دوائر مختلفة، تشمل مجالات خبرتهم السياسة والاقتصاد والمجتمع والوضع الوطني وتاريخ دبلوماسية الحزب الشيوعي الصيني والاستراتيجية العسكرية وإدارة ممتلكات الدولة والرعاية الصحية والأعمال التجارية الخاصة. وتختلف موضوعات المقابلات على نطاق واسع؛ فمن النظم والنظرية والتطوير والإصلاح، إلى نوعية الحياة والاستراتيجية والدبلوماسية وجميع من كان فيها يؤيدون التعلم من الحضارات الإنسانية، ولكنهم يصرون في الوقت نفسه على ضرورة اتخاذ مسار يناسب الصين بدلا من استنساخ النموذج الغربي. يأتي هذا الكتاب من ضمن سلسلة تتألف من ثلاثة كتب وهي : الثقة في المسار : نموذج جديد لقوة صاعدة، الثقة في النظرية : فلسفة الصين لنظام دولي جديد، والثقة في النظام : نجاح نظام التنمية \"البديل\" في الصين. بما يوفر للقارئ مقاربة نظرية وواقعية لمسار الصين ونظريتها ونظامها، ويشرح أسباب ثقة الدولة الصينية في خياراتها.
Book
Mechanical stress determines the configuration of TGFβ activation in articular cartilage
Our incomplete understanding of osteoarthritis (OA) pathogenesis has significantly hindered the development of disease-modifying therapy. The functional relationship between subchondral bone (SB) and articular cartilage (AC) is unclear. Here, we found that the changes of SB architecture altered the distribution of mechanical stress on AC. Importantly, the latter is well aligned with the pattern of transforming growth factor beta (TGFβ) activity in AC, which is essential in the regulation of AC homeostasis. Specifically, TGFβ activity is concentrated in the areas of AC with high mechanical stress. A high level of TGFβ disrupts the cartilage homeostasis and impairs the metabolic activity of chondrocytes. Mechanical stress stimulates talin-centered cytoskeletal reorganization and the consequent increase of cell contractile forces and cell stiffness of chondrocytes, which triggers αV integrin–mediated TGFβ activation. Knockout of αV integrin in chondrocytes reversed the alteration of TGFβ activation and subsequent metabolic abnormalities in AC and attenuated cartilage degeneration in an OA mouse model. Thus, SB structure determines the patterns of mechanical stress and the configuration of TGFβ activation in AC, which subsequently regulates chondrocyte metabolism and AC homeostasis.
The functional relationship between subchondral bone and articular cartilage is unclear. Here, the authors show that transforming growth factor-beta propagates the mechanical impact of subchondral bone on articular cartilage through αV integrin–talin mechanical transduction system in chondrocytes.
Journal Article
Realization of a crosstalk-avoided quantum network node using dual-type qubits of the same ion species
Generating ion-photon entanglement is a crucial step for scalable trapped-ion quantum networks. To avoid the crosstalk on memory qubits carrying quantum information, it is common to use a different ion species for ion-photon entanglement generation such that the scattered photons are far off-resonant for the memory qubits. However, such a dual-species scheme can be subject to inefficient sympathetic cooling due to the mass mismatch of the ions. Here we demonstrate a trapped-ion quantum network node in the dual-type qubit scheme where two types of qubits are encoded in the
S
and
F
hyperfine structure levels of
171
Yb
+
ions. We generate ion photon entanglement for the
S
-qubit in a typical timescale of hundreds of milliseconds, and verify its small crosstalk on a nearby
F
-qubit with coherence time above seconds. Our work demonstrates an enabling function of the dual-type qubit scheme for scalable quantum networks.
In ion-photon quantum network platforms, usually memory qubits and communication qubits are encoded in ions of different species. Here, instead, the authors show how to realise ion-photon entanglement within the same-species-dual-encoding scheme.
Journal Article
A site-resolved two-dimensional quantum simulator with hundreds of trapped ions
A large qubit capacity and an individual readout capability are two crucial requirements for large-scale quantum computing and simulation
1
. As one of the leading physical platforms for quantum information processing, the ion trap has achieved a quantum simulation of tens of ions with site-resolved readout in a one-dimensional Paul trap
2
–
4
and of hundreds of ions with global observables in a two-dimensional (2D) Penning trap
5
,
6
. However, integrating these two features into a single system is still very challenging. Here we report the stable trapping of 512 ions in a 2D Wigner crystal and the sideband cooling of their transverse motion. We demonstrate the quantum simulation of long-range quantum Ising models with tunable coupling strengths and patterns, with or without frustration, using 300 ions. Enabled by the site resolution in the single-shot measurement, we observe rich spatial correlation patterns in the quasi-adiabatically prepared ground states, which allows us to verify quantum simulation results by comparing the measured two-spin correlations with the calculated collective phonon modes and with classical simulated annealing. We further probe the quench dynamics of the Ising model in a transverse field to demonstrate quantum sampling tasks. Our work paves the way for simulating classically intractable quantum dynamics and for running noisy intermediate-scale quantum algorithms
7
,
8
using 2D ion trap quantum simulators.
In this work, stable trapping of a two-dimensional Wigner crystal of above 500 ions is achieved, and the quantum simulation of 300 ions with individual state detection demonstrated.
Journal Article
Unmasking chloride attack on the passive film of metals
Nanometer-thick passive films on metals usually impart remarkable resistance to general corrosion but are susceptible to localized attack in certain aggressive media, leading to material failure with pronounced adverse economic and safety consequences. Over the past decades, several classic theories have been proposed and accepted, based on hypotheses and theoretical models, and oftentimes, not sufficiently nor directly corroborated by experimental evidence. Here we show experimental results on the structure of the passive film formed on a FeCr
15
Ni
15
single crystal in chloride-free and chloride-containing media. We use aberration-corrected transmission electron microscopy to directly capture the chloride ion accumulation at the metal/film interface, lattice expansion on the metal side, undulations at the interface, and structural inhomogeneity on the film side, most of which had previously been rejected by existing models. This work unmasks, at the atomic scale, the mechanism of chloride-induced passivity breakdown that is known to occur in various metallic materials.
Collecting experimental evidence of chloride ion attack on protective passive metallic films due to corrosion remains challenging. Here, the authors show that the boundaries between nanocrystals and amorphous regions in the passive film ease chloride transport even as they do not coincide with areas of high chloride concentration.
Journal Article
Realizing coherently convertible dual-type qubits with the same ion species
Trapped ions constitute one of the most promising systems for implementing quantum computing and networking
1
,
2
. For large-scale ion-trap-based quantum computers and networks, it is critical to have two types of qubit: one for computation and storage, and another for auxiliary operations such as qubit detection
3
, sympathetic cooling
4
–
7
and entanglement generation through photon links
8
,
9
. Although the two qubit types can be implemented using two different ion species
3
,
10
–
13
, this approach introduces substantial complexity into creating and controlling each qubit type
14
,
15
. Here we resolve these challenges by implementing two coherently convertible qubit types using one ion species. We encode the qubits into two pairs of clock states of the
171
Yb
+
ions, and achieve microsecond-level conversion rates between the two types with one-way fidelities of 99.5%. We further demonstrate that operations on one qubit type, including sympathetic laser cooling, single-qubit gates and qubit detection, have crosstalk errors less than 0.06% on the other type, which is below the best-known error threshold of ~1% for fault-tolerant quantum computing using the surface code
1
,
16
. Our work establishes the feasibility and advantages of using coherently convertible dual-type qubits with the same ion species for large-scale quantum computing and networking.
Quantum computing with trapped ions requires qubits that can store and manipulate quantum information, and others that can be used for destructive incoherent operations. Different states of ytterbium-171 ions can be used to realize both qubit types
Journal Article
Agyrotropic Electron Distributions in the Terrestrial Foreshock Transients
Agyrotropic electron distributions are frequently taken as an indicator of electron diffusion regions of magnetic reconnection. However, they have also been found at electron‐scale boundaries of the non‐reconnecting magnetopause and are generated by the electron finite gyroradius effect. Here, we present magnetospheric multiscale observations of agyrotropic electron distributions in the foreshock region. These distributions are generated by the electron finite gyroradius effect after magnetic curvature scattering at a thin electron‐scale boundary. Meanwhile, the signatures of magnetic reconnection are absent at this boundary. The test‐particle simulation is adopted to verify the generation of the agyrotropic electron distributions by assuming one‐dimensional magnetic geometry. These observations suggest that agyrotropic electron distributions can be more widely formed at electron‐scale boundaries in space plasma environment. Plain Language Summary The agyrotropic electron distributions, which could be unstable to generate high frequency electrostatic waves, reveal valuable information of electron dynamics at electron scales. However, due to electron's small mass, the related observational study becomes only possible with the high‐resolution magnetospheric multiscale data. In this study, we show that the agyrotropic electron distributions can be also formed in the foreshock transients such as inside an hot flow anomaly, suggesting that agyrotropic electron distributions are ubiquitous in space plasma. Key Points We present the first magnetospheric multiscale observations of agyrotropic electron distributions in the foreshock transients Accompanied with the agytropic electron distributions, clear signatures of magnetic reconnection are absent The agytropic electron distributions are formed by the electron finite gyroradius effect at electron‐scale boundaries
Journal Article
Quantum interference in heterogeneous superconducting-photonic circuits on a silicon chip
Quantum information processing holds great promise for communicating and computing data efficiently. However, scaling current photonic implementation approaches to larger system size remains an outstanding challenge for realizing disruptive quantum technology. Two main ingredients of quantum information processors are quantum interference and single-photon detectors. Here we develop a hybrid superconducting-photonic circuit system to show how these elements can be combined in a scalable fashion on a silicon chip. We demonstrate the suitability of this approach for integrated quantum optics by interfering and detecting photon pairs directly on the chip with waveguide-coupled single-photon detectors. Using a directional coupler implemented with silicon nitride nanophotonic waveguides, we observe 97% interference visibility when measuring photon statistics with two monolithically integrated superconducting single-photon detectors. The photonic circuit and detector fabrication processes are compatible with standard semiconductor thin-film technology, making it possible to implement more complex and larger scale quantum photonic circuits on silicon chips.
Scaling photonic quantum information processing approaches remains challenging for integrated quantum optics. Here, Schuck
et al.
develop a hybrid superconducting-photonic circuit system to show how quantum interference and single-photon detectors can be combined in a scalable fashion on a silicon chip.
Journal Article
Dependence of mechanical properties of trabecular bone on plate–rod microstructure determined by individual trabecula segmentation (ITS)
Individual trabecula segmentation (ITS) technique can decompose the trabecular bone network into individual trabecular plates and rods and is capable of quantifying the plate/rod-related microstructural characteristics of trabecular bone. This novel technique has been shown to be able to provide in-depth insights into micromechanics and failure mechanisms of human trabecular bone, as well as to distinguish the fracture status independent of area bone mineral density in clinical applications. However, the plate/rod microstructural parameters from ITS have never been correlated to experimentally determined mechanical properties of human trabecular bone. In this study, on-axis cylindrical trabecular bone samples from human proximal tibia (n=22), vertebral body (n=10), and proximal femur (n=21) were harvested, prepared, scanned using micro computed-tomography (µCT), analyzed with ITS and mechanically tested. Regression analyses showed that the plate bone volume fraction (pBV/TV) and axial bone volume fraction (aBV/TV) calculated by ITS analysis correlated the best with elastic modulus (R2=0.96–0.97) and yield strength (R2=0.95–0.96). Trabecular plate-related microstructural parameters correlated highly with elastic modulus and yield strength, while most rod-related parameters were found inversely and only moderately correlated with the mechanical properties. In addition, ITS analysis also identified that trabecular bone at human femoral neck had the highest trabecular plate-related parameters while the other sites were similar with each other in terms of plate–rod microstructure.
Journal Article
