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The purpose of this paper is to understand whether the personal capital of the entrepreneur positively or negatively affects outcomes from self-employment.

Data from the UK’s longitudinal household surveys (BHPS, UKLHS) between 1991 and 2014 were analysed. Relationships between age, education, health and family status, income earned and hours worked were tested.

Entrepreneurs with higher levels of personal capital enjoyed higher incomes. However, those with lower levels of personal capital were more likely to have negative returns from self-employment, and so experience it as “self-exploitation”.

A basis for understanding different outcomes from self-employment was developed and tested.

Specific characteristics of continuing and new entrepreneurs were identified that are positively associated with beneficial outcomes from self-employment.

Positive and negative outcomes from self-employment are explained. The notion of personal capital is developed as an explanatory framework for variable outcomes from self-employment.

The purpose of this paper is to investigate the determinants of self-employment, using data from the British Household Panel Survey.

Using the maximum likelihood estimation, the authors estimate the Probit models via disaggregation of the sample by male and female, and inclusion of regional and industrial controls.

This paper finds that the intergenerational links in self-employment run significantly through father-son, and mother-daughter. In addition, the authors find that lump-sum endowment, aspiration, marriage and education attainment are all significant and positive determinants for female self-employed while insignificant for male self-employed. Variables including number of children, health of the individual, and age effect are more important determinants for male than for female self-employed.

The findings show that there are significant differences between male and female self-employed. Future studies on self-employment should therefore distinguish the two genders in their econometric models.

The authors reinforce and add to the exiting literature on gender differences in the determinants of self-employment. The authors disaggregate the data by gender, and introduce some important variables for empirical studies, such as father self-employed, mother self-employed, aspiration, health of the individual, and age effect.

This study aims to accurately simulate the tilting separation process of mask projection stereolithography (MPSL) and verify the tilting theory.

The finite element separation models of MPSL 3D printing process were established. The established models simulated both tilting and pulling-up separation process by changing the constraints and boundary conditions. The bilinear cohesive curves were used to define the separation interface. The stress distribution of the cured part and FEP film at different times during the whole separation process was extracted. Different orientations of pulling-up and tilting were also compared for stress distribution. The stress change was analyzed for the center and edge points of the upper surface of cured part.

The results showed that the stress increased with the separation speed, and the stress at the edge position of exposure area was greater than the internal position. The tilting traction stress distribution was affected by the exposure area function and the velocity distribution. Alternation of the exposure area function changed the cohesive stiffness. The non-coincidence of the calculated traction stress with the input bilinear cohesive curve reflected the influence of the material properties and the separation methods. The high-speed side of tilting had fast separation and high traction stress.

This study proposes a technical method for simulation tilting separation and verified the tilting theory. The cohesive zone model was proved applicable to the tilting traction stress calculation.

This study aims to develop a multi-material stereolithography (MMSL) technique to directly fabricate a biphasic osteochondral scaffold.

A bespoke prototype MMSL system was developed based on a bottom-up mask projection approach. The system was controlled by a multi-material fabrication algorithm with minimum number of switching cycles during fabrication. A variable-power light source was used to fabricate materials with significantly different curing characteristics. The light-curable poly(ethylene glycol) diacrylate (PEGDA) hydrogel and beta-tricalcium phosphate (β-TCP) ceramic suspension were used for fabricating the biphasic osteochondral scaffold.

The bonding strength of the multi-material interface is shown to be mainly affected by the type of photopolymer, rather than the switching of the materials in MMSL. Lighting power densities of 2.64 and 14.98 mW/cm2 were used for curing the PEGDA hydrogel and the ß-TCP ceramic suspension, respectively. A biphasic osteochondral scaffold with complex interface was successfully fabricated.

This study proposes a potential technical method (MMSL) for manufacturing a complex biphasic osteochondral scaffold composing a PEGDA hydrogel/ß-TCP ceramic composite in a time-efficient and precise manner. The designed bone-cartilage scaffold interface and the surface of the cartilage scaffold can be precisely manufactured.

This study aims to systematically investigate the tribological behaviors of metal and polyethylene using lubricants composed of four synovial fluid (SF) components. In addition, the changes in protein conformation during wear were analyzed to establish the correlation between protein conformation and tribological properties.

A pin-on-disk tester with multidirectional sliding motion was used for tribological properties observation between metal and polyethylene pairs. Simulated SFs with four main constituents were used as the testing lubricants. Differential scanning calorimetry and Raman were used to characterize the changes in protein conformation during wear.

The coupling of lipids and hyaluronic acid further suppressed protein denaturation. The protein structures of the adsorption film and the ensnared protein chains in the friction zone were maintained to a certain extent, thus improving the friction and wear of polyethylene.

These findings established the correlation between protein conformation and friction and wear, promoting the understanding of the lubrication mechanism of artificial joints.

The purpose of this paper is to fabricate and characterize osteochondral beta‐tricalcium phosphate/collagen scaffold with bio‐inspired design by ceramic stereolithography (CSL) and gel casting.

Histological analysis was applied to explore the morphological characteristics of the transitional structure between the bone and the cartilage. The acquired data were used to design biomimetic biphasic scaffolds, which include the bone phase, cartilage phase, and their transitional structure. The engineered scaffolds were fabricated from β‐TCP‐collagen by CSL and gel casting. The cartilage phase was added to the ceramic phase by gel‐casting and freeze drying.

The resulting ceramic scaffolds were composed of a bone phase with the following properties: 700‐900 μm pore size, 200‐500 μm interconnected pores size, 50‐65 percent porosity, fully interconnected, ∼12 Mpa compressive strength. A suitable binding force between cartilage phase and ceramic phase was achieved by physical locking that was created by the biomimetic transitional structure. Cellular evaluation showed satisfactory results.

This study is the first try to apply CSL to fabricate biological implants with β‐TCP and type‐I collagen. There are still some defects in the composition of the slurry and the fabrication process.

This strategy of osteochondral scaffold fabrication can be implemented to construct an osteochondral complex that is similar to native tissue.

The CSL technique is highly accurate, as well as biologically secure, when fabricating ceramic tissue engineering scaffolds and may be a promising method to construct hard tissue with delicate structures. The present strategy enhances the versatility of scaffold fabrication by RP.

The purpose of this paper is to propose strategies for satellite cluster non‐coplanar orbit transfer to reduce fuel cost of formation maintenance and orbit maneuver.

This research tries to use geometric method model to describe the relative motion of satellites in the cluster non‐coplanar orbit transfer, and genetic algorithm (GA) to optimize the proposed maneuver strategies.

Compared with the C‐W equations, the geometric method model is found to be more precise. Three strategies are proposed and optimized to maintain the relative orbit and a strategy of indefinite phase and non‐synchronous costs least fuel.

Geometric method model can be used to describe the relative motion of satellite cluster, especially on elliptical orbits considering the effects of perturbation, with a simple form and good accuracy. Fuel cost minimization is one of the most important issues in formation flight mission.

This paper provides dynamics analysis about formation non‐coplanar orbit transfer, which is involved in minor researches.

This study aims to understand the epistemic foundation of the classification applied in the first Chinese library catalogue, the Seven Epitomes (Qilue).

Originating from a theoretical stance that situates knowledge organization in its social context, the study applies a multifaceted framework pertaining to five categories of textual data: the Seven Epitomes; biographical information about the classificationist Liu Xin; and the relevant intellectual, political, and technological history.

The study discovers seven principles contributing to the epistemic foundation of the catalogue's classification: the Han imperial library collection imposed as the literary warrant; government functions considered for structuring texts; classicist morality determining the main classificatory structure; knowledge perceived and organized as a unity; objects, rather than subjects, of concern affecting categories at the main class level; correlative thinking connecting all text categories to a supreme knowledge embodied by the Six Classics; and classicist moral values resulting in both vertical and horizontal hierarchies among categories as well as texts.

A major limitation of the study is its focus on the main classes, with limited attention to subclasses. Future research can extend the analysis to examine subclasses of the same scheme. Findings from these studies may lead to a comparison between the epistemic approach in the target classification and the analytic one common in today's bibliographic classification.

The study is the first to examine in depth the epistemic foundation of traditional Chinese bibliographic classification, anchoring the classification in its appropriate social and historical context.

The purpose of this paper is to analyze the mechanism and filter efficacy of accumulation generation operator (AGO)/inverse accumulation generation operator (IAGO) in the frequency domain.

The AGO/IAGO in time domain will be transferred to the frequency domain by the Fourier transform. Based on the consistency of the mathematical expressions of the AGO/IAGO in the gray system and the digital filter in digital signal processing, the equivalent filter model of the AGO/IAGO is established. The unique methods in digital signal processing systems “spectrum analysis” of AGO/IAGO are carried out in the frequency domain.

Through the theoretical study and practical example, benefit of spectrum analysis is explained, and the mechanism and filter efficacy of AGO/IAGO are quantitatively analyzed. The study indicated that the AGO is particularly suitable to act on the system's behavior time series in which the long period parts is the main factor. The acted sequence has good effect of noise immunity.

The AGO/IAGO has a wonderful effect on the processing of some statistical data, e.g. most of the statistical data related to economic growth, crop production, climate and atmospheric changes are mainly affected by long period factors (i.e. low-frequency data), and most of the disturbances are short-period factors (high-frequency data). After processing by the 1-AGO, its high frequency content is suppressed, and its low frequency content is amplified. In terms of information theory, this two-way effect improves the signal-to-noise ratio greatly and reduces the proportion of noise/interference in the new sequence. Based on 1-AGO acting, the information mining and extrapolation prediction will have a good effect.

The authors find that 1-AGO has a wonderful effect on the processing of data sequence. When the 1-AGO acts on a data sequence X, its low-pass filtering effect will benefit the information fluctuations removing and high-frequency noise/interference reduction, so the data shows a clear exponential change trends. However, it is not suitable for excessive use because its equivalent filter has poles at the non-periodic content. But, because of pol effect at zero frequency, the 1-AGO will greatly amplify the low-frequency information parts and suppress the high-frequency parts in the information at the same time.

The purpose of this paper is to provide a foundational reference and practical guidance for modelling small and poor data with incomplete information.

The definitions of four basic models of GM(1, 1), such as Even Grey Model (EGM), Original Difference Grey Model (ODGM), Even Difference Grey Model (EDGM) and Discrete Grey Model (DGM), are put forward. The properties and characteristics of different models are studied and their equivalence are proved. The suitable sequences of different models are studied by simulation and analysis with homogeneous exponential sequences, nonhomogeneous exponential increasing sequences and vibration sequences.

The main conclusions have been obtained as follows: first, the three discrete models of ODGM, EDGM and DGM are suitable for homogeneous exponential sequences or sequences which close to a homogeneous exponential sequence; and second the EGM are suitable for nonhomogeneous exponential increasing sequences and vibration sequences.

The outcome obtained in this paper can be consulted for model selection in the course of practical modelling.

This paper systematically defined the four basic forms of model GM(1, 1) and studied their properties and characteristics, especially their suitable sequences. Although significant progress has been made in this field, such a systematic study on these models and their suitable sequences is still missing as far as we know. It can provide reference and basis for people to choose the correct model in the actual modelling process.